BACKGROUND OF THE INVENTION

This invention relates to resin compositions, more particularly to polyesters with enhanced flame retardant (FR) properties.

Many applications of engineering plastics require polymers that have flame retardant properties along with other properties such as tensile strength, long-term thermal stability, high heat deflection temperature and chemical resistance.

Saturated aromatic linear polyesters such as polyethylene terephthalate and polybutylene terephthalate are very useful plastic materials for producing shaped articles including films and filaments. These polymers, however, do not have entirely satisfactory thermal stability. For example, when exposed to high temperatures, they tend to decrease in the degree of polymerization and consequently decrease in mechanical strength. These polyesters also are not inherently flame retardant and their compositions commonly include flame retardant additives to render them suitable for many applications.

Many attempts have been made in the past to improve thermal stability, flame retardancy and other properties of these polyesters simultaneously by incorporating various additives, but all of them faced some deficiencies or the other. Usually, an attempt to improve one property resulted in undesirable deterioration in another.

Normally flame retardant properties are achieved by adding large amounts of flame retardant additives to polyester compositions. Due to large amount of FR additives required to achieve the desired FR properties, other properties, in particular impact strength and elongation at break are adversely affected. Important requirements of flame retardant are: pale intrinsic color, sufficient thermal stability for incorporation in thermoplastics, and its efficacy in reinforced and non-reinforced polymers.

The choice of flame retardants used is guided by the degree of flame retardancy required as well as stability and other performance properties of compositions containing thermoplastic resins. As an illustration, nitrogen-containing FR systems, such as melamine cyanurate, has limited efficacy in thermoplastics, e.g. polyamide. In reinforced polyamide, it is effective only in combination with shortened glass fibers. In polyesters, melamine cyanurate alone is not effective. Also, phosphorus-containing FR systems used in isolation, are generally not effective in polyesters. Phosphorus/nitrogen-containing FR systems, e.g. ammonium polyphosphates or melamine phosphates, have disadvantages of thermal instability when used in thermoplastics processed above 200Â° C.

Among the various flame retardants used in polyester compositions, phosphorus based flame retardants are quite popular. Among the phosphorus based flame retardants, phosphinate compounds are more preferred for polyesters. When metal phosphinates are used alone or combined with other flame retardants in some thermoplastics, there is generally some degree of polymer degradation, which has an adverse effect on mechanical properties. Addition of additives intended to counteract polymer degradation brought about by hydrolysis and thermal stress during processing, via chain extension is well known in the art. These additives are known as chain extenders and permit preparation of high-molecular-weight polymers. The use of chain extenders in combination with a phosphinate or phosphorus containing agglomerates is disclosed in U.S. Pat. No. 6,538,054B1, US20050137300A1, and US20050143503A1 where some amount of epoxy compound has been added as an auxiliary additive. The U.S. Pat. No. 4,196,066 teaches the use of an unsaturated additive and an epoxy group to improved cross linking speeds and cross linking densities. Molded objects comprising a polyester containing unsaturated diol or unsaturated diacid components, flame retardants, reinforcing fillers, impact modifiers with better short time deflection temperatures have been disclosed in US Patent 20020180098 A1.

It is known that the mechanical properties, particularly the rigidity, of polyester molding compositions may be improved by the addition of fibers and fillers. It is necessary also to offset the disadvantages to mechanical properties, when flame retardant agents like halogen or phosphorus compounds are added to the reinforced polyester molding compositions. Contact with an open flame leads to the formation of a relatively low viscosity melt, which means that burning material may drip off, possibly to ignite any flammable material present below. Addition of bifunctional epoxide based on bisphenol A and epichlorohydrin to the glass fiber reinforced polymer is disclosed in GB patent GB1525771.

There is a continuing need to make polyesters which are inherently less flammable so that lower loadings of FR additives are sufficient to achieve the desired FR properties simultaneously maintaining the mechanical properties like impact strength and elongation at break at an acceptable level.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment of the present invention a flame retardant resin composition comprising a) a polyester; wherein said polyester comprises from about 1 to about 15 mole percent of an unsaturated diol; b) 1 weight percent to about 40 weight percent based on the total weight of the composition of a flame retardant compound; and c) 0.1 weight percent to about 5 weight percent based on the total weight of the composition an organic compound wherein said organic compound comprises of at least one carboxyl reactive group. In one embodiment the composition further comprises a saturated polyester or a polycarbonate.

In one embodiment of the present invention, is disclosed the method of synthesizing the composition and articles derived from said composition.

Various other features, aspects, and advantages of the present invention will become more apparent with reference to the following description, examples, and appended claims.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included herein. In this specification and in the claims, which follow, reference will be made to a number of terms which shall be defined to have the following meanings.

The singular forms â€œaâ€ , â€œanâ€ and â€œtheâ€ include plural referents unless the context clearly dictates otherwise.

â€œOptionalâ€ or â€œoptionallyâ€ means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

â€œCombinationâ€ as used herein includes mixtures, copolymers, reaction products, blends, composites, and the like.

Other than in the operating examples or where otherwise indicated, all numbers or expressions referring to quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as modified in all instances by the term â€œabout.â€ Various numerical ranges are disclosed in this patent application. Because these ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations

As used herein the term â€œaliphatic radicalâ€ refers to a radical having a valence of at least one comprising a linear or branched array of atoms which is not cyclic. The array may include heteroatoms such as nitrogen, sulfur, silicon, selenium and oxygen or may be composed, exclusively of carbon and hydrogen. Aliphatic radicals may be â€œsubstitutedâ€ or â€œunsubstitutedâ€ . A substituted aliphatic radical is defined as an aliphatic radical which comprises at least one substituent. A substituted aliphatic radical may comprise as many substituents as there are positions available on the aliphatic radical for substitution. Substituents which may be present on an aliphatic radical include but are not limited to halogen atoms such as fluorine, chlorine, bromine, and iodine. Substituted aliphatic radicals include trifluoromethyl, hexafluoroisopropylidene, chloromethyl; difluorovinylidene; trichloromethyl, bromoethyl, bromotrimethylene (e.g. â€”CH₂CHBrCH₂â€”), and the like. For convenience, the term â€œunsubstituted aliphatic radicalâ€ is defined herein to encompass, as part of the â€œlinear or branched array of atoms which is not cyclicâ€ comprising the unsubstituted aliphatic radical, a wide range of functional groups. Examples of unsubstituted aliphatic radicals include allyl, aminocarbonyl (i.e. â€”CONH₂), carbonyl, dicyanoisopropylidene (i.e. â€”CH₂C(CN)₂CH₂â€”), methyl (i.e. â€”CH₃), methylene (i.e. â€”CH₂â€”), ethyl, ethylene, formyl, hexyl, hexamethylene, hydroxymethyl (i.e. â€”CH₂OH), mercaptomethyl (i.e. â€”CH₂SH), methylthio (i.e. â€”SCH₃), methylthiomethyl (i.e. â€”CH₂SCH₃), methoxy, methoxycarbonyl, nitromethyl (i.e. â€”CH₂NO₂), thiocarbonyl, trimethylsilyl, t-butyldimethylsilyl, trimethyoxysilypropyl, vinyl, vinylidene, and the like. Aliphatic radicals are defined to comprise at least one carbon atom. A C₁-C₁₀aliphatic radical includes substituted aliphatic radicals and unsubstituted aliphatic radicals containing at least one but no more than 10 carbon atoms.

As used herein, the term â€œaromatic radicalâ€ refers to an array of atoms having a valence of at least one comprising at least one aromatic group. The array of atoms having a valence of at least one comprising at least one aromatic group may include heteroatoms such as nitrogen, sulfur, selenium, silicon and oxygen, or may be composed exclusively of carbon and hydrogen. As used herein, the term â€œaromatic radicalâ€ includes but is not limited to phenyl, pyridyl, furanyl, thienyl, naphthyl, phenylene, and biphenyl radicals. As noted, the aromatic radical contains at least one aromatic group. The aromatic group is invariably a cyclic structure having 4n+2 â€œdelocalizedâ€ electrons where â€œnâ€ is an integer equal to 1 or greater, as illustrated by phenyl groups (n=1), thienyl groups (n=1), furanyl groups (n=1), naphthyl groups (n=2), azulenyl groups (n=2), anthracenyl groups (n=3) and the like. The aromatic radical may also include nonaromatic components. For example, a benzyl group is an aromatic radical which comprises a phenyl ring (the aromatic group) and a methylene group (the nonaromatic component). Similarly a tetrahydronaphthyl radical is an aromatic radical comprising an aromatic group (C₆H₃) fused to a nonaromatic component â€”(CH₂)₄^âˆ’. Aromatic radicals may be â€œsubstitutedâ€ or â€œunsubstitutedâ€ . A substituted aromatic radical is defined as an aromatic radical which comprises at least one substituent. A substituted aromatic radical may comprise as many substituents as there are positions available on the aromatic radical for substitution. Substituents which may be present on an aromatic radical include, but are not limited to halogen atoms such as fluorine, chlorine, bromine, and iodine. Substituted aromatic radicals include trifluoromethylphenyl, hexafluoroisopropylidenebis(4-phenyloxy) (i.e. â€”OPhC(CF₃)₂PhOâ€”), chloromethylphenyl; 3-trifluorovinyl-2-thienyl; 3-trichloromethylphenyl (i.e. 3-CCl₃Ph-), bromopropylphenyl (i.e. BrCH₂CH₂CH₂Ph-), and the like. For convenience, the term â€œunsubstituted aromatic radicalâ€ is defined herein to encompass, as part of the â€œarray of atoms having a valence of at least one comprising at least one aromatic groupâ€ , a wide range of functional groups. Examples of unsubstituted aromatic radicals include 4-allyloxyphenoxy, aminophenyl (i.e. H₂NPh-), aminocarbonylphenyl (i.e. NH₂COPh-), 4-benzoylphenyl, dicyanoisopropylidenebis(4-phenyloxy) (i.e. â€”OPhC(CN)₂PhOâ€”), 3-methylphenyl, methylenebis(4-phenyloxy) (i.e. â€”OPhCH₂PhOâ€”), ethylphenyl, phenylethenyl, 3-formyl-2-thienyl, 2-hexyl-5-furanyl; hexamethylene-1,6-bis(4-phenyloxy) (i.e. â€”OPh(CH₂)₆PhOâ€”); 4-hydroxymethylphenyl (i.e. 4-HOCH₂Ph-), 4-mercaptomethylphenyl (i.e. 4-HSCH₂Ph-), 4-methylthiophenyl (i.e. 4-CH₃SPh-), methoxyphenyl, methoxycarbonylphenyloxy (e.g. methyl salicyl), nitromethylphenyl (i.e. -PhCH₂NO₂), trimethylsilylphenyl, t-butyldimethylsilylphenyl, vinylphenyl, vinylidenebis(phenyl), and the like. The term â€œa C₃-C₁₀aromatic radicalâ€ includes substituted aromatic radicals and unsubstituted aromatic radicals containing at least three but no more than 10 carbon atoms. The aromatic radical 1-imidazolyl (C₃H₂N₂â€”) represents a C₃aromatic radical. The benzyl radical (C₇H₈â€”) represents a C₇aromatic radical.

As used herein the term â€œcycloaliphatic radicalâ€ refers to a radical having a valence of at least one, and comprising an array of atoms which is cyclic but which is not aromatic. As defined herein a â€œcycloaliphatic radicalâ€ does not contain an aromatic group. A â€œcycloaliphatic radicalâ€ may comprise one or more noncyclic components. For example, a cyclohexylmethyl group (C₆H₁₁CH₂â€”) is an cycloaliphatic radical which comprises a cyclohexyl ring (the array of atoms which is cyclic but which is not aromatic) and a methylene group (the noncyclic component). The cycloaliphatic radical may include heteroatoms such as nitrogen, sulfur, selenium, silicon and oxygen, or may be composed exclusively of carbon and hydrogen. Cycloaliphatic radicals may be â€œsubstitutedâ€ or â€œunsubstitutedâ€ . A substituted cycloaliphatic radical is defined as a cycloaliphatic radical which comprises at least one substituent. A substituted cycloaliphatic radical may comprise as many substituents as there are positions available on the cycloaliphatic radical for substitution. Substituents which may be present on a cycloaliphatic radical include but are not limited to halogen atoms such as fluorine, chlorine, bromine, and iodine. Substituted cycloaliphatic radicals include trifluoromethylcyclohexyl, hexafluoroisopropylidenebis(4-cyclohexyloxy) (i.e. â€”OC₆H₁₁C(CF₃)₂C₆H₁₁Oâ€”), chloromethylcyclohexyl; 3-trifluorovinyl-2-cyclopropyl; 3-trichloromethylcyclohexyl (i.e. 3-CCl₃C₆H₁₁â€”), bromopropylcyclohexyl (i.e. BrCH₂CH₂CH₂C₆H₁₁â€”), and the like. For convenience, the term â€œunsubstituted cycloaliphatic radicalâ€ is defined herein to encompass a wide range of functional groups. Examples of unsubstituted cycloaliphatic radicals include 4-allyloxycyclohexyl, aminocyclohexyl (i.e. H₂NC₆H₁₁â€”), aminocarbonylcyclopenyl (i.e. NH₂COC₅H₉â€”), 4-acetyloxycyclohexyl, dicyanoisopropylidenebis(4-cyclohexyloxy) (i.e. â€”OC₆H₁₁C(CN)₂C₆H₁₁Oâ€”), 3-methylcyclohexyl, methylenebis(4-cyclohexyloxy) (i.e. â€”OC₆H₁₁CH₂C₆H₁₁Oâ€”), ethylcyclobutyl, cyclopropylethenyl, 3-formyl-2-tetrahydrofuranyl, 2-hexyl-5-tetrahydrofuranyl; hexamethylene-1,6-bis(4-cyclohexyloxy) (i.e. â€”OC₆H₁₁(CH₂)₆C₆H₁₁Oâ€”); 4-hydroxymethylcyclohexyl (i.e. 4-HOCH₂C₆H₁₁â€”), 4-mercaptomethylcyclohexyl (i.e. 4-HSCH₂C₆H₁₁â€”), 4-methylthiocyclohexyl (i.e. 4-CH₃SC₆H₁₁â€”), 4-methoxycyclohexyl, 2-methoxycarbonylcyclohexyloxy (2-CH₃OCO C₆H₁₁Oâ€”), nitromethylcyclohexyl (i.e. NO₂CH₂C₆H₁₀â€”), trimethylsilylcyclohexyl, t-butyldimethylsilylcyclopentyl, 4-trimethoxysilylethylcyclohexyl (e.g. (CH₃O)₃SiCH₂CH₂C₆H₁₀â€”), vinylcyclohexenyl, vinylidenebis(cyclohexyl), and the like. The term â€œa C₃-C₁₀cycloaliphatic radicalâ€ includes substituted cycloaliphatic radicals and unsubstituted cycloaliphatic radicals containing at least three but no more than 10 carbon atoms. The cycloaliphatic radical 2-tetrahydrofuranyl (C₄H₇Oâ€”) represents a C₄cycloaliphatic radical. The cyclohexylmethyl radical (C₆H₁₁CH₂â€”) represents a C₇cycloaliphatic radical.

The present invention describes a flame retardant resin composition comprising a) a polyester; wherein said polyester comprises from about 1 to about 15 mole percent of an unsaturated diol; b) 1 weight percent to about 40 weight percent based on the total weight of the composition of a flame retardant compound; and c) 0.1 weight percent to about 5 weight percent based on the total weight of the composition an organic compound wherein said organic compound comprises of at least one carboxyl reactive group. Surprisingly, the composition of this invention provide improved flammability rating with retention of mechanical properties.

Typically such polyester resins include crystalline polyester resins such as polyester resins derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, containing from 2 to about 10 carbon atoms and at least one aromatic dicarboxylic acid. Preferred polyesters are derived from an aliphatic diol and an aromatic dicarboxylic acid and have repeating units according to structural formula (I) [Image Omitted]
wherein, R¹is independently at each occurrence a monovalent hydrocarbon group, alkyl, aryl, arylalkyl, alkylaryl, or cycloalkyl group and R²is independently at each occurrence comprises a mono-valent hydrocarbon group, alkenyl, allyl, alkyl, aryl, aralkyl, alkaryl, cycloalkyl, alkyne, or alkene group. In one embodiment R²is an alkyl radical compromising a dehydroxylated residue derived from an aliphatic or cycloaliphatic diol, or mixtures thereof, containing from 2 to about 20 carbon atoms and R¹is an aryl radical comprising a decarboxylated residue derived from an aromatic dicarboxylic acid. The polyester is a condensation product where R²is the residue of an aryl, alkane or cycloalkane containing diol having 6 to 20 carbon atoms or chemical equivalent thereof, and R¹is the decarboxylated residue derived from an aryl, aliphatic or cycloalkane containing diacid of 6 to 20 carbon atoms or chemical equivalent thereof. The polyester resins are typically obtained through the condensation or ester interchange polymerization of the diol or diol equivalent component with the diacid or diacid chemical equivalent component.

The diacids meant to include carboxylic acids having two carboxyl groups each useful in the preparation of the polyester resins of the present invention are preferably aliphatic, aromatic, cycloaliphatic. Examples of diacids are cyclo or bicyclo aliphatic acids, for example, decahydro naphthalene dicarboxylic acids, norbornene dicarboxylic acids, bicyclo octane dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid or chemical equivalents, and the most preferred is trans-1,4-cyclohexanedicarboxylic acid or a chemical equivalent. Linear dicarboxylic acids like adipic acid, azelaic acid, dodecane dicarboxylic acid, and succinic acid may also be useful. Chemical equivalents of these diacids include esters, alkyl esters, e.g., dialkyl esters, diaryl esters, anhydrides, salts, acid chlorides, acid bromides, and the like. Examples of aromatic dicarboxylic acids from which the decarboxylated residue R¹may be derived are acids that contain a single aromatic ring per molecule such as, e.g., isophthalic or terephthalic acid, 1,2-di(p-carboxyphenyl)ethane, 4,4â€²-dicarboxydiphenyl ether, 4,4â€²-bisbenzoic acid and mixtures thereof, as well as acids contain fused rings such as, e.g. 1,4-, 1,5-, or 2,6-naphthalene dicarboxylic acids. Preferred dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acids, and the like, and mixtures comprising at least one of the foregoing dicarboxylic acids.

Examples of the carboxylic acid include, but are not limited to, an aromatic polyvalent carboxylic acid, an aromatic oxycarboxylic acid, an aliphatic dicarboxylic acid, and an alicyclic dicarboxylic acid, including terephthalic acid, isophthalic acid, ortho-phthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene 2,7-dicarboxylic acid, 5-[4-sulfophenoxy]isophthalic acid, sulfoterephthalic acid, p-oxybenzoic acid, p-(hydroxyethoxy)benzoic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trimellitic acid, trimesic acid, and pyrromellitic acid. These may be used in the form of metal salts and ammonium salts and the like.

Some of the diols useful in the preparation of the polyester resins of the present invention are straight chain, branched, or cycloaliphatic alkane diols and may contain from 2 to 12 carbon atoms. Examples of such diols include but are not limited to ethylene glycol; propylene glycol, i.e., 1,2- and 1,3-propylene glycol; 2,2-dimethyl-1,3-propane diol; 2-ethyl, 2-methyl, 1,3-propane diol; 1,3- and 1,5-pentane diol; dipropylene glycol; 2-methyl-1,5-pentane diol; 1,6-hexane diol; dimethanol decalin, dimethanol bicyclo octane; 1,4-cyclohexane dimethanol and particularly its cis- and trans-isomers; triethylene glycol; 1,10-decane diol; and mixtures of any of the foregoing. In one embodiment the diol include glycols, such as ethylene glycol, propylene glycol, butanediol, hydroquinone, resorcinol, trimethylene glycol, 2-methyl-1,3-propane glycol, 1,4-butanediol, hexamethylene glycol, decamethylene glycol, 1,4-cyclohexane dimethanol, or neopentylene glycol. Chemical equivalents to the diols include esters, such as dialkylesters, diaryl esters, and the like.

Examples of the alcohol include, but are not limited to, an aliphatic polyvalent alcohol, an alicyclic polyvalent alcohol, and an aromatic polyvalent alcohol, including ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanediol, tricyclodecanedimethanol, m-xylene glycol, o-xylene glycol, 1,4-phenylene glycol, bisphenol A, lactone polyester and polyols. Further, with respect to the polyester resin obtained by polymerizing the polybasic carboxylic acids and the polyhydric alcohols either singly or in combination respectively, a resin obtained by capping the polar group in the end of the polymer chain using an ordinary compound capable of capping an end can also be used.

Typically the polyester resin may comprise one or more resins selected from linear polyester resins, branched polyester resins and copolymeric polyester resins. Suitable linear polyester resins include, e.g., poly(alkylene phthalate)s such as, e.g., poly(ethylene terephthalate) (â€œPETâ€ ), poly(butylene terephthalate) (â€œPBTâ€ ), poly(propylene terephthalate) (â€œPPTâ€ ), poly(cycloalkylene phthalate)s such as, e.g., poly(cyclohexanedimethyleneterephthalate) (â€œPCTâ€ ), poly(cyclohexanedimethylenecyclohexanedicarboxylate) (PCCD), poly(alkylene naphthalate)s such as, e.g., poly(butylene-2,6-naphthalate) (â€œPBNâ€ ) and poly(ethylene-2,6-naphthalate) (â€œPENâ€ ). In another embodiment suitable copolymeric polyester resins include, e.g., polyesteramide copolymers, cyclohexanedimethanol-terephthalic acid-isophthalic acid copolymers and cyclohexanedimethanol-terephthalic acid-ethylene glycol copolymers. In one embodiment suitable copolymeric polyester resin include, e.g., cyclohexanedimethanol-terephthalic acid-isophthalic acid copolymers and cyclohexanedimethanol-terephthalic acid-ethylene glycol copolymers.

Preferred polyesters are obtained by copolymerizing a glycol component and an acid component comprising at least about 70 mole %, preferably at least about 80 mole %, of terephthalic acid, or polyester-forming derivatives thereof. The preferred glycol, tetramethylene glycol, component can contain up to about 30 mole %, preferably up to about 20 mole % of another glycol, such as ethylene glycol, trimethylene glycol, 2-methyl-1,3-propane glycol, hexamethylene glycol, decamethylene glycol, cyclohexane dimethanol, neopentylene glycol, and the like, and mixtures comprising at least one of the foregoing glycols. The preferred acid component may contain up to about 30 mole %, preferably up to about 20 mole %, of another acid such as isophthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 4,4â€²-diphenyl dicarboxylic acid, 4,4â€²-diphenoxyethanedicarboxylic acid, sebacic acid, adipic acid, 1,2- or 1,3- or 1,4-cyclohexane dicarboxylic acid or its ester derivatives and the like, and polyester-forming derivatives thereof, and mixtures comprising at least one of the foregoing acids or acid derivatives.

Block copolyester resin components are also useful, and can be prepared by the transesterification of (a) straight or branched chain poly(alkylene terephthalate) and (b) a copolyester of a linear aliphatic dicarboxylic acid and, optionally, an aromatic dibasic acid such as terephthalic or isophthalic acid with one or more straight or branched chain dihydric aliphatic glycols. Especially useful when high melt strength is important are branched high melt viscosity resins, which include a small amount of, e.g., up to 5 mole percent based on the acid units of a branching component containing at least three ester forming groups. The branching component can be one that provides branching in the acid unit portion of the polyester, in the glycol unit portion, or it can be a hybrid branching agent that includes both acid and alcohol functionality. Illustrative of such branching components are tricarboxylic acids, such as trimesic acid, and lower alkyl esters thereof, and the like; tetracarboxylic acids, such as pyromellitic acid, and lower alkyl esters thereof, and the like; or preferably, polyols, and especially preferably, tetrols, such as pentaerythritol; triols, such as trimethylolpropane; dihydroxy carboxylic acids; and hydroxydicarboxylic acids and derivatives, such as dimethyl hydroxyterephthalate, and the like. Branched poly(alkylene terephthalate) resins and their preparation are described, for example, in U.S. Pat. No. 3,953,404 to Borman. In addition to terephthalic acid units, small amounts, e.g., from 0.5 to 15 mole percent of other aromatic dicarboxylic acids, such as isophthalic acid or naphthalene dicarboxylic acid, or aliphatic dicarboxylic acids, such as adipic acid, can also be present, as well as a minor amount of diol component other than that derived from 1,4-butanediol, such as ethylene glycol or cyclohexylenedimethanol, etc., as well as minor amounts of trifunctional, or higher, branching components, e.g., pentaerythritol, trimethyl trimesate, and the like.

The polyesters in one embodiment of the present invention may be a polyether ester block copolymer consisting of a thermoplastic polyester as the hard segment and a polyalkylene glycol as the soft segment. It may also be a three-component copolymer obtained from at least one dicarboxylic acid selected from: aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4-dicarboxylic acid, diphenoxyethanedicarboxylic acid or 3-sulfoisophthalic acid, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid or dimeric acid, and ester-forming derivatives thereof; at least one diol selected from: aliphatic diols such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol or decamethylene glycol, alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol or tricyclodecanedimethanol, and ester-forming derivatives thereof; and at least one poly(alkylene oxide) glycol selected from: polyethylene glycol or poly (1,2- and 1,3-propylene oxide) glycol with an average molecular weight of about 400-5000, ethylene oxide-propylene oxide copolymer, and ethylene oxide-tetrahydrofuran copolymer.

The polyester can be present in the composition at about 20 to about 90 weight percent, based on the total weight of the composition. Within this range, it is preferred to use at least about 25 weight percent, even more preferably at least about 30 weight percent of the polyester such as poly(butylene terephthalate). The preferred polyesters preferably have an intrinsic viscosity (as measured in 60:40 solvent mixture of phenol/tetrachloroethane at 25Â° C.) ranging from about 0.1 to about 1.5 deciliters per gram. Polyesters branched or unbranched generally will have a weight average molecular weight of from about 5,000 to about 150,000, preferably from about 8,000 to about 95,000 as measured by gel permeation chromatography. It is contemplated that the polyesters have various known end groups.

Preferably the amount of catalyst present is less than about 200 ppm. Typically, catalyst may be present in a range from about 20 to about 300 ppm.

In one embodiment the polyester comprises 1 to 15 mole percent of an unsaturated diol. In another embodiment the polyester comprises olefinic or acetylinic covalent bonds introduced by an unsaturated diol. In one embodiment the unsaturated diols comprise structural units of the formula (II). [Image Omitted]
wherein R³, R⁴, R⁵, and R⁶are independently at each occurrence, selected from the group consisting of a hydrogen atom, C₁to C₃₀aliphatic radical, C₃-C₃₀cycloaliphatic radical, and C₃-C₃₀aromatic radical.

In one embodiment the unsaturated diols comprise structural units of the formula (II). [Image Omitted]
wherein R⁷, R⁸, R⁹, R¹⁰, R¹¹and R¹²are independently at each occurrence, selected from the group consisting of a hydrogen atom, C₁to C₃₀aliphatic radical, C₃-C₃₀cycloaliphatic radical, and C₃-C₃₀aromatic radical.

In another embodiment, said unsaturated diol is at least one selected from the group consisting of alkene diols, alkyne diols, and cycloalkene diols. In yet another embodiment, the unsaturated diol is at least one selected from the group consisting of but-2-ene-1,4-diol, hex-2-ene-1,6-diol, hex-3-ene-1,6-diol, pent-2-ene-1,5-diol, 3-methyl-pent-2-ene-1,5-diol. In one embodiment the polyester comprises about 5 to about 12 mole percent of said unsaturated diol. The diols can exist in both cis and trans forms. A typical ratio of cis to trans form is about 95 to about 5 and is not limited to this value. But-2-ene-1,4-diol used for the preparation of the polyester compositions of the invention was purchased from Aldrich Chemicals, USA and had a ratio of cis to trans 95:5.

A preferred polyester can have a number average molecular weight of about 10,000 atomic mass units (AMU) to about 200,000 AMU, as measured by gel permeation chromatography using polystyrene standards. Within this range, a number average molecular weight of at least about 20,000 AMU is preferred. Also within this range, a number average molecular weight of up to about 100,000 AMU is preferred, and a number average molecular weight of up to about 50,000 AMU is more preferred.

In one embodiment, the flame retardant compound comprises a phosphorus containing compound. Non-limiting examples of phosphorus compounds of the phosphine class are aromatic phosphines, such as triphenylphosphine, tritolylphosphine, trinonylphosphine, trinaphthylphosphine, tetraphenyldiphosphine, tetranaphthyldiphosphine and the like. Suitable phosphine oxides are of the formula (IV) [Image Omitted]
wherein R¹³, R¹⁴and R¹⁵are independently at each occurrence, selected from the group consisting of a C₁to C₃₀aliphatic radical, C₃-C₃₀cycloaliphatic radical, and C₃-C₃₀aromatic radical. Examples of phosphine oxides are triphenylphosphine oxide, tritolylphosphine oxide, trisnonylphenylphosphine oxide, tricyclohexylphosphine oxide, tris(n-butyl)phosphine oxide, tris(n-hexyl)phosphine oxide, tris(n-octyl)phosphine oxide, tris(cyanoethyl)phosphine oxide, benzylbis(cyclohexyl)phosphine oxide, benzylbisphenylphosphine oxide and phenylbis(n-hexyl)phosphine oxide. Other suitable compounds are triphenylphosphine sulfide and its derivatives as described above for phosphine oxides and triphenyl phosphate.

Other examples of phosphorus compounds are hypophosphites, e.g. metal hypophosphites where metal is a alkali metal, alkaline earth metal or a transition metal or Al. Ca, Al, Zn, Ti, Mg, Ba and the like and organic hypophosphites, such as cellulose hypophosphite esters, esters of hypophosphorous acids with diols, e.g. that of 1,10-dodecanediol.

In one embodiment the phosphorus compound may be a phosphinate (e.g. A₁,A₂-P(â• O)(OA₃), wherein A₁, A₂and A₃are independently at any occurrence a C₁to C₃₀aliphatic radical, C₃-C₃₀cycloaliphatic radical, and C₃-C₃₀aromatic radical. Examples of phosphinic acids which are suitable constituents of the phosphinates are: dimethylphosphinic acid, ethylimethyphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid), benzene-1,4-(dimethylphosphinic acid), methylphenylphosphinic acid and diphenylphosphinic acid. Other examples of phosphorus compounds are metal salts of the above dialkyl or diaryl or arylalkyl phosphinic acid, where metal is an alkali metal, Li, Na, K and Cs and the like or alkaline earth metal, Be, Ca, Mg, Ba, Sr and the like or a transition metal, Zn, Ti and the like or other main group elements such as Al, Sn, Sb and the like. These phosphinate salts can be monomeric or polymeric in structure. Some of these compounds are inorganic coordination polymers of aryl(alkyl)phosphinic acids, such as poly-Î²-sodium(I)ethylphenylphosphinate, zinc salt of diethyl phosphinic acid, etc.

It is also possible to use substituted phosphinic acids and anhydrides, e.g. diphenylphosphinic acid. Other possible compounds are di-p-tolylphosphinic acid and dicresylphosphinic anhydride. Compounds such as the bis(diphenylphosphinic)esters of hydroquinone, ethylene glycol and propylene glycol, inter alia, may also be used. Other suitable compounds are aryl(alkyl)phosphinamides, such as the dimethylamide of diphenylphosphinic acid, and sulfonamidoaryl(alkyl)phosphinic acid derivatives, such as p-tolylsulfonamidodiphenylphosphinic acid. In one embodiment the flame retardant compound is bis(diphenylphosphinic)esters of hydroquinone and ethylene glycol and of the bis(diphenylphosphinate) of hydroquinone.

Other suitable examples are derivatives of phosphorous acid. Suitable compounds are cyclic phosphonates which derive from pentaerythritol, from neopentyl glycol or from pyrocatechol. In another embodiment other phosphorus based flame retardants are triaryl(alkyl)phosphites, such as triphenyl phosphite, tris(4-decylphenyl)phosphite, tris(2,4-di-tert-butylphenyl)phosphite and phenyl didecyl phosphite. It is also possible to use diphosphites, such as propylene glycol 1,2-bis(diphosphite) or cyclic phosphites which derive from pentaerythritol, from neopentylglycol or from pyrocatechol.

In one embodiment the flame retardant is at least one selected from the group consisting of neopentyl glycol methylphosphonate and methyl neopentyl glycol phosphite, pentaerythritol dimethyldiphosphonate, dimethyl pentaerythritol diphosphate, tetraphenyl hypodiphosphate and bisneopentyl hypodiphosphate.

Other effective phosphorus based flame retardants are particularly alkyl- and aryl-substituted phosphates. Examples of these are phenyl bisdodecyl phosphate, phenyl ethyl hydrogen phosphate, phenyl bis(3,5,5-trimethylhexyl)phosphate, ethyl diphenyl phosphate, 2-ethylhexyl ditolyl phosphate, diphenyl hydrogen phosphate, bis(2-ethylhexyl)p-tolyl phosphate, tritolyl phosphate, bis(2-ethylhexyl)phenyl phosphate, di(nonyl)phenyl phosphate, phenyl methyl hydrogenphosphate, di(dodecyl)p-tolyl phosphate, p-tolylbis(2,5,5-trimethylhexyl)phosphate and 2-ethylhexyl diphenyl phosphate. Particularly suitable phosphorus compounds are those in which each radical is aryloxy. Very particularly suitable compounds are triphenyl phosphate, Bisphenol-A bis (diphenyl phosphate) and resorcinol bis(diphenyl phosphate) and its ring-substituted derivatives of formula (V): [Image Omitted]
wherein R¹⁶to R²⁰are each occurrence aromatic radicals having from 6 to 20 carbon atoms, preferably phenyl, which may have substitution by alkyl groups having from 1 to 4 carbon atoms, preferably methyl, R²²is a bivalent phenol radical, preferably and n is an average value of from 0.1 to 100, preferably from 0.5 to 50, in particular from 0.8 to 10 and very particularly from 1 to 5. It is also possible to use cyclic phosphates like for example diphenyl pentaerythritol diphosphate and phenyl neopentyl phosphate are particularly suitable. Other suitable flame retardants are elemental red phosphorous and also compounds that contain phosphorous nitrogen bonds, such as phosphononitrile chloride, phosphoric acid ester amides, phosphoric acid amides, phosphonic acid amides, phosphinic acid amides, tris(aziridinyl)-phosphinic oxide and tetrakis(hydroxymethyl)phosphonium chloride.

In one embodiment the flame retardant may be a halogenated flame retardant. The examples of halogenated flame retardants where brominated flame retardants are preferred are tetrabromobisphenol A derivatives, including bis(2-hydroxyethyl)ether of tetrabromobisphenol A, bis(3-acryloyloxy-2-hydroxypropyl)ether of tetrabromobisphenol A, bis(3-methacryloyloxy-2-hydroxypropyl)ether of tetrabromobisphenol A, bis(3-hydroxypropyl)ether of tetrabromobisphenol A, bis(2,3-dibromopropyl)ether of tetrabromobisphenol A, diallyl ether of tetrabromobisphenol A, and bis(vinylbenzyl)ether of tetrabromobisphenol A; brominated polycarbonates, tetrabromobisphenol A polycarbonate oligomer, brominated polyacrylate such as polypentabromobenzyl acrylate; brominated polystyrenes, such as polydibromostyrenes and polytribromostyrenes; brominated BPA polyepoxides, tetrabromocyclooctanes; dibromoethyldibromocyclohexanes such as 1,2-dibromo-4-(1,2-dibromoethyl)-cyclohexane; ethylene-bis-tetrabromophthalimide; hexabromocyclododecanes; tetrabromophthalic anhydrides; brominated diphenylethers such as decabromodiphenyl ether; poly(2,6-dibromophenylene ether); and tris(2,4,6-tribromophenoxy-1,3,5-triazine etc.

Flame retardance may also be imparted to the compositions by the inclusion of brominated thermosetting resins, for example a brominated poly(epoxide), or a poly(arylene ether) having a phosphorous-containing moiety in its backbone.

The organic compound comprising at least one carboxyl reactive group is selected from the group consisting of aliphatic or aromatic compounds. The functional group is selected from the group consisting of epoxy, carbodiimide, orthoesters, anhydrides, oxazoline, imidazoline, isocyanates. In a preferred embodiment the functional group is selected from the group consisting of epoxy, carbodiimide, and orthoester.

According to an embodiment, the organic compound comprising at least one carboxyl reactive group may include multifunctional epoxies. In one embodiment the stabilized composition of the present invention may optionally comprise at least one epoxy-functional polymer. One epoxy polymer is an epoxy functional (alkyl)acrylic monomer and at least one non-functional styrenic and/or (alkyl)acrylic monomer. In one embodiment, the epoxy polymer has at least one epoxy-functional (meth)acrylic monomer and at least one non-functional styrenic and/or (meth)acrylic monomer which are characterized by relatively low molecular weights. In another embodiment the epoxy functional polymer may be epoxy-functional styrene (meth)acrylic copolymers produced from monomers of at least one epoxy functional (meth)acrylic monomer and at least one non-functional styrenic and/or (meth)acrylic monomer. As used herein, the term (meth)acrylic includes both acrylic and methacrylic monomers. Non limiting examples of epoxy-functional (meth)acrylic monomers include both acrylates and methacrylates. Examples of these monomers include, but are not limited to, those containing 1,2-epoxy groups such as glycidyl acrylate and glycidyl methacrylate. Other suitable epoxy-functional monomers include allyl glycidyl ether, glycidyl ethacrylate, and glycidyl itaconate.

Epoxy functional materials suitable for use as the carboxyl reactive group contain aliphatic or cycloaliphatic epoxy or polyepoxy functionalization. Generally, epoxy functional materials suitable for use herein are derived by the reaction of an epoxidizing agent, such as peracetic acid, and an aliphatic or cycloaliphatic point of unsaturation in a molecule. Other functionalities which will not interfere with an epoxidizing action of the epoxidizing agent may also be present in the molecule, for example, esters, ethers, hydroxy, ketones, halogens, aromatic rings, etc. A well known class of epoxy functionalized materials are glycidyl ethers of aliphatic or cycloaliphatic alcohols or aromatic phenols. The alcohols or phenols may have more than one hydroxyl group. Suitable glycidyl ethers may be produced by the reaction of, for example, monophenols or diphenols such as bisphenol-A with epichlorohydrin. Polymeric aliphatic epoxides might include, for example, copolymers of glycidyl methacrylate or allyl glycidyl ether with methyl methacrylate, styrene, acrylic esters or acrylonitrile.

Specifically, the epoxies that can be employed herein include glycidol, bisphenol-A diglycidyl ether, tetrabromobisphenol-A diglycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, epoxidized soybean oil, butadiene diepoxide, tetraphenylethylene epoxide, dicyclopentadiene dioxide, vinylcyclohexene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.

According to an embodiment, such additional carboxyl reactive groups may include reactive oxazoline compounds, which are also known as cyclic imino ether compounds. Such compounds are described in Van Benthem, Rudolfus A. T. et al., U.S. Pat. No. 6,660,869 or in Nakata, Yoshitomo et al., U.S. Pat. No. 6,100,366. Examples of such compounds are phenylene bisoxazolines, 1,3-PBO, 1,4-PBO, 1,2-naphthalene bisoxazoline, 1,8-naphthalene bisoxazoline, 1,11-dimethyl-1,3-PBO and 1,11-dimethyl-1,4-PBO.

In another embodiment, the carboxyl reactive group can be oligomeric copolymer of vinyl oxazoline and acrylic monomers. Specific examples of preferable oxazoline monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-5,5-dihydro-4H-1,3-oxazoline, 2-isopropenyl-2-oxazoline, and 4,4-dimethyl-2-isopropenyl-2-oxazoline. Particularly, 2-isopropenyl-2-functional materials suitable for use herein are derived by the reaction of an epoxidizing agent, such as peracetic acid, and an aliphatic or cycloaliphatic point of unsaturation in a molecule. Other functionalities which will not interfere with an epoxidizing action of the epoxidizing agent may also be present in the molecule, for example, esters, ethers, hydroxy, ketones, halogens, aromatic rings, etc. A well known class of epoxy functionalized materials are glycidyl ethers of aliphatic or cycloaliphatic alcohols or aromatic phenols. The alcohols or phenols may have more than one hydroxyl group. Suitable glycidyl ethers may be produced by the reaction of, for example, monophenols or diphenols such as bisphenol-A with epichlorohydrin. Polymeric aliphatic epoxides might include, for example, copolymers of glycidyl methacrylate or allyl glycidyl ether with methyl methacrylate, styrene, acrylic esters or acrylonitrile.

Specifically, the epoxies that can be employed herein include glycidol, bisphenol-A diglycidyl ether, tetrabromobisphenol-A diglycidyl ether, diglycidyl ester of phthalic acid, diglycidyl ester of hexahydrophthalic acid, epoxidized soybean oil, butadiene diepoxide, tetraphenylethylene epoxide, dicyclopentadiene dioxide, vinylcyclohexene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.

According to an embodiment, such additional carboxyl reactive groups may include reactive oxazoline compounds, which are also known as cyclic imino ether compounds. Such compounds are described in Van Benthem, Rudolfus A. T. et al., U.S. Pat. No. 6,660,869 or in Nakata, Yoshitomo et al., U.S. Pat. No. 6,100,366. Examples of such compounds are phenylene bisoxazolines, 1,3-PBO, 1,4-PBO, 1,2-naphthalene bisoxazoline, 1,8-naphthalene bisoxazoline, 1,11-dimethyl-1,3-PBO and 1,11-dimethyl-1,4-PBO.

In another embodiment, the carboxyl reactive group can be oligomeric copolymer of vinyl oxazoline and acrylic monomers. Specific examples of preferable oxazoline monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-5,5-dihydro-4H-1,3-oxazoline, 2-isopropenyl-2-oxazoline, and 4,4-dimethyl-2-isopropenyl-2-oxazoline. Particularly, 2-isopropenyl-2-oxazoline and 4,4-dimethyl-2-isopropenyl-2-oxazoline are preferable, because they show good copolymerizability. The monomer component may further include other monomers copolymerizable with the cyclic imino ether group containing monomer. Examples of such other monomers include unsaturated alkyl carboxylate monomers, aromatic vinyl monomers, and vinyl cyanide monomers. These other monomers may be used either alone respectively or in combinations with each other. Examples of the unsaturated alkyl carboxylate monomer include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, iso-butyl(meth)acrylate, t-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, iso-nonyl(meth)acrylate, dodecyl(meth)acrylate, and stearyl(meth)acrylate, styrene and Î±-methyl styrene.

In one embodiment the organic compound comprising at least one functional group is selected from the group consisting of epoxy and orthoester. In one embodiment the organic compound comprising at least one functional group is of the formula (VI) [Image Omitted]
wherein R²¹, R²², R²³are independently at any occurrence an alkyl, alkoxy, aromatic, aryloxy, hydroxy, or hydrogen. In yet another embodiment the organic compound containing at least one functional group is of the formula (VII)
wherein R²⁴, R²⁵are independently at each occurrence selected from the group consisting of alkyl, aromatic, hydrogen and R²⁶is an aromatic radical.

The epoxy functionalized materials are added to the thermoplastic blend in amounts effective to improve compatibility as evidenced by both visual and measured physical properties associated with compatibility. A person skilled in the art may determine the optimum amount for any given epoxy functionalized material. Generally, from about 0.01 to about 10.0 weight parts of the epoxy functional material should be added to the thermoplastic blend for each 100 weight parts thermoplastic resin. Preferably, from about 0.05 weight parts to about 5.0 weight parts epoxy functional material should be added.

The ratio of reactants in the composition of the present invention is important. In one embodiment the polyester is present in a range from about 10 to about 90 weight percent. In one embodiment, the composition comprises the polyester in the range of from about 35 weight percent to about 60 weight percent. Typically, the organic compound comprising at least one carboxyl reactive compound is present in a range of from about 0.1 weight percent to about 5 weight percent based on the total weight of the composition. In another embodiment the carboxyl reactive compound is present in a range of from about 0.15 weight percent to about 2.5 weight percent based on the total weight of the composition. In yet another embodiment the carboxyl reactive compound is present in a range of from about 0.2 weight percent to about 1.5 weight percent based on the total weight of the composition. In one embodiment of the present invention the flame retardant is present in the range of from about 0.1 weight percent to about 40 weight percent based on the total weight of the composition. In another embodiment, the flame retardant is present in the range of from about 5 weight percent to about 15 weight percent based on the total weight of the composition.

The polyester composition of the present invention may further comprise a nitrogen compound. The nitrogen compound used in the invention is not particularly limited as long as it is an organic or inorganic compound containing nitrogen. In one embodiment the nitrogen compound may be an optional component of the polyester composition. Non-limiting representative examples of the nitrogen compound may be nitrogen-containing compounds, such as amines, amides, azo compounds, compounds having a triazine ring, salts formed by ionic bonding of a plurality of the same or difference compounds selected from the aforementioned triazine ring compounds, compounds formed through condensation of a plurality of the same or different compounds selected therefrom, and the like. Compounds having triazine rings may be, for example, cyanuric acid, 2-methyl-4,6-diamino-triazine, 2,4d-dimethyl-6-amino-triazine, 2-methyl-4,6-dihydroxy-triazine, 2,4-dimethyl-6-hydroxy-triazine, trimethyl triazine, tris(hydroxymethyl)triazine, tris(1-hydroxyethyl)triazine, tris(2-hydroxyethyl)triazine, isocyanuric acid, tris(hydroxymethyl)isocyanurate, tris(1-hydroxyethyl)isocyanurate, tris(2-hydroxyethyl)isocyanurate, triallyl isocyanurate, and the like.

Besides, melamine and the like are also included in the nitrogen compounds. The melamine and the like refer to melamine, melamine derivatives, compounds having a similar structure to that of melamine, condensates of melamine, and the like. For example, melamine, ammeride, ammerine, benzoguanamine, acetoguanamine, formoguanamine, guanyl melamine, cyanomelamine, aryl guanamine, melam, melem, melon, succinoguanmine, adipoguanamine, methylglutaroguanamine, melamine phosphate, and the like. The nitrogen compound used in the invention is preferably cyanuric acid, isocyanuric acid, melamine, melamine cyanurate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine formaldehyde and the like. In one embodiment the amount of nitrogen compound is in the range of between about 0 to about 20 weight percent based on the total weight of the composition.

In one embodiment of the present invention the thermoplastic resin composition may optionally comprise stabilizing additives. In another embodiment the stabilizing additives, called quenchers are used in the present invention to stop the polymerization reaction. Quenchers are agents that inhibit activity of any catalysts that may be present in the resins to prevent an accelerated interpolymerization and degradation of the thermoplastic. The suitability of a particular compound for use as a stabilizer and the determination of how much is to be used as a stabilizer may be readily determined by preparing a mixture of the polyester resin component and the polycarbonate and determining the effect on melt viscosity, gas generation or color stability or the formation of interpolymer. In one embodiment of the quenchers are for example of phosphorous containing compounds, boric containing acids, aliphatic or aromatic carboxylic acids i.e., organic compounds the molecule of which comprises at least one carboxy group, anhydrides, polyols.

The choice of the quencher is essential to avoid color formation and loss of clarity of the thermoplastic composition. In one embodiment of the invention, the catalyst quenchers are phosphorus containing derivatives, examples include but are not limited to diphosphites, phosphonates, metaphosphoric acid; arylphosphinic and arylphosphonic acids; polyols; carboxylic acid derivatives and combinations thereof. The amount of the quencher added to the thermoplastic composition is an amount that is effective to stabilize the thermoplastic composition. In one embodiment the amount is at least about 0.001 weight percent, preferably at least about 0.01 weight percent based on the total amounts of said thermoplastic resin compositions. The amount of quencher used is thus an amount which is effective to stabilize the composition therein but insufficient to substantially deleteriously affect substantially most of the advantageous properties of said composition.

The composition of the present invention may include additives which do not interfere with the previously mentioned desirable properties but enhance other favorable properties such as anti-oxidants, flame retardants, reinforcing materials, colorants, mold release agents, fillers, nucleating agents, UV light and heat stabilizers, lubricants, and the like. Additionally, additives such as antioxidants, minerals such as talc, clay, mica, and other stabilizers including but not limited to UV stabilizers, such as benzotriazole, supplemental reinforcing fillers such as flaked or milled glass, and the like, flame retardants, pigments or combinations thereof may be added to the compositions of the present invention.

The compositions may, optionally, further comprise a reinforcing filler. The fillers may be of natural or synthetic, mineral or non-mineral origin, provided that the fillers have sufficient thermal resistance to maintain their solid physical structure at least at the processing temperature of the composition with which it is combined. Suitable fillers include clays, nanoclays, carbon black, wood flour either with or without oil, various forms of silica (precipitated or hydrated, fumed or pyrogenic, vitreous, fused or colloidal, including common sand), glass, metals, inorganic oxides (such as oxides of the metals in Periods 2, 3, 4, 5 and 6 of Groups Ib, IIb, IIIa, IIIb, IVa, IVb (except carbon), Va, VIa, VIIa and VIII of the Periodic Table), oxides of metals (such as aluminum oxide, titanium oxide, zirconium oxide, titanium dioxide, nanoscale titanium oxide, aluminum trihydrate, vanadium oxide, and magnesium oxide), hydroxides of aluminum or ammonium or magnesium, carbonates of alkali and alkaline earth metals (such as calcium carbonate, barium carbonate, and magnesium carbonate), antimony trioxide, calcium silicate, diatomaceous earth, fuller earth, kieselguhr, mica, talc, slate flour, volcanic ash, cotton flock, asbestos, kaolin, alkali and alkaline earth metal sulfates (such as sulfates of barium and calcium sulfate), titanium, zeolites, wollastonite, titanium boride, zinc borate, tungsten carbide, ferrites, molybdenum disulfide, asbestos, cristobalite, aluminosilicates including Vermiculite, Bentonite, montmorillonite, Na-montmorillonite, Ca-montmorillonite, hydrated sodium calcium aluminum magnesium silicate hydroxide, pyrophyllite, magnesium aluminum silicates, lithium aluminum silicates, zirconium silicates, and combinations comprising at least one of the foregoing fillers. Suitable fibrous fillers include glass fibers, basalt fibers, aramid fibers, carbon fibers, carbon nanofibers, carbon nanotubes, carbon buckyballs, ultra high molecular weight polyethylene fibers, melamine fibers, polyamide fibers, cellulose fiber, metal fibers, potassium titanate whiskers, and aluminum borate whiskers.

Alternatively, or in addition to a particulate filler, the filler may be provided in the form of monofilament or multifilament fibers and may be used either alone or in combination with other types of fiber, through, for example, co-weaving or core/sheath, side-by-side, orange-type or matrix and fibril constructions, or by other methods known to one skilled in the art of fiber manufacture. Suitable cowoven structures include, for example, glass fiber-carbon fiber, carbon fiber-aromatic polyimide(aramid) fiber, and aromatic polyimide fiberglass fiber or the like. Fibrous fillers may be supplied in the form of, for example, rovings, woven fibrous reinforcements, such as 0-90 degree fabrics or the like; non-woven fibrous reinforcements such as continuous strand mat, chopped strand mat, tissues, papers and felts or the like; or three-dimensional reinforcements such as braids.

Optionally, the fillers may be surface modified, for example treated so as to improve the compatibility of the filler and the polymeric portions of the compositions, which facilitates deagglomeration and the uniform distribution of fillers into the polymers. One suitable surface modification is the durable attachment of a coupling agent that subsequently bonds to the polymers. Use of suitable coupling agents may also improve impact, tensile, flexural, and/or dielectric properties in plastics and elastomers; film integrity, substrate adhesion, weathering and service life in coatings; and application and tooling properties, substrate adhesion, cohesive strength, and service life in adhesives and sealants. Suitable coupling agents include silanes, titanates, zirconates, zircoaluminates, carboxylated polyolefins, chromates, chlorinated paraffins, organosilicon compounds, and reactive cellulosics. The fillers may also be partially or entirely coated with a layer of metallic material to facilitate conductivity, e.g., gold, copper, silver, and the like.

In a preferred embodiment, the reinforcing filler comprises glass fibers. For compositions ultimately employed for electrical uses, it is preferred to use fibrous glass fibers comprising lime-aluminum borosilicate glass that is relatively soda free, commonly known as â€œEâ€ glass. However, other glasses are useful where electrical properties are not so important, e.g., the low soda glass commonly known as â€œCâ€ glass. The glass fibers may be made by standard processes, such as by steam or air blowing, flame blowing and mechanical pulling. Preferred glass fibers for plastic reinforcement may be made by mechanical pulling. The diameter of the glass fibers is generally from about 1 to about 50 micrometers, preferably from about 1 to about 20 micrometers. Smaller diameter fibers are generally more expensive, and glass fibers having diameters from about 10 to about 20 micrometers presently offer a desirable balance of cost and performance. The glass fibers may be bundled into fibers and the fibers bundled in turn to yarns, ropes or rovings, or woven into mats, and the like, as is required by the particular end use of the composition. In preparing the molding compositions, it is convenient to use the filamentous glass in the form of chopped strands of about one-eighth to about 2 inches long, which usually results in filament lengths from about 0.0005 to about 0.25 inch in the molded compounds. Such glass fibers are normally supplied by the manufacturers with a surface treatment compatible with the polymer component of the composition, such as a siloxane, titanate, or polyurethane sizing, or the like.

When present in the composition, the reinforcing filler may be used at an amount ranging from about 0 to about 50 weight percent, based on the total weight of the composition. Within this range, it is preferred to use at least about 20 weight percent of the reinforcing filler. Also within this range, it is preferred to use up to about 50 weight percent, more preferably up to about 40 weight percent, of the reinforcing filler.

The flame retardants are typically used with a synergist, particularly inorganic antimony compounds, especially when halogenated flame-retardants are used. Such compounds are widely available or can be made in known ways. Typical, inorganic synergist compounds include Sb₂O₅, SbS₃, sodium antimonate and the like. Especially preferred is antimony trioxide (Sb₂O₃). Synergists such as antimony oxides, are typically used at about 0.1 to 10 by weight based on the weight percent of resin in the final composition. Also, the final composition may contain polytetrafluoroethylene (PTFE) type resins or copolymers used to reduce dripping in flame retardant thermoplastics. Also other halogen-free flame retardants than the mentioned P or N containing compounds can be used, non limiting examples being compounds as Zn-borates, hydroxides or carbonates as Mg- and/or Al-hydroxides or carbonates, Si-based compounds like silanes or siloxanes, Sulfur based compounds as aryl sulphonates (including salts of it) or sulphoxides, Sn-compounds as stannates can be used as well often in combination with one or more of the other possible flame retardants. Synergists may also include charring polymers such as polyetherimide, polyphenyleneoxide, polyethersulfone, polyphenylene sulfone, polyphenylene sulfide, NOVOLACÂ® resins, and the like.

Other additional ingredients may include antioxidants, and UV absorbers, and other stabilizers. Antioxidants include i) alkylated monophenols, for example: 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(alpha-methylcyclohexyl)-4,6 dimethylphenol, 2,6-di-octadecyl-4-methylphenol, 2,4,6-tricyclohexyphenol, 2,6-di-tert-butyl-4-methoxymethylphenol; ii) alkylated hydroquinones, for example, 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4octadecyloxyphenol; iii) hydroxylated thiodiphenyl ethers; iv) alkylidene-bisphenols; v) benzyl compounds, for example, 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene; vi) acylaminophenols, for example, 4-hydroxy-lauric acid anilide; vii) esters of beta-(3,5-di-tert-butyl-4-hydroxyphenol)-propionic acid with monohydric or polyhydric alcohols; viii) esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid with monohydric or polyhydric alcohols; vii) esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, e.g., with methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris(hydroxyethyl)isocyanurate, thiodiethylene glycol, N,N-bis(hydroxyethyl)oxalic acid diamide. Typical, UV absorbers and light stabilizers include i) 2-(2â€²-hydroxyphenyl)-benzotriazoles, for example, the 5â€²methyl-,3â€²5â€²-di-tert-butyl-,5â€²-tert-butyl-,5â€²(1,1,3,3-tetramethylbutyl)-,5-chloro-3â€²,5â€²-di-tert-butyl,5-chloro-3â€²tert-butyl-5â€²methyl-,3â€²sec-butyl-5â€²tert-butyl-,4â€²-octoxy,3â€²,5â€²-ditert-amyl-3â€²,5â€²-bis-(alpha, alpha-dimethylbenzyl)-derivatives; ii) 2.2 2-Hydroxy-berizophenones, for example, the 4-hydroxy-4-methoxy-,4-octoxy,4-decloxy-,4-dodecyloxy-,4-benzyloxy,4,2â€²,4â€²-trihydroxy- and 2â€²hydroxy-4,4â€²-dimethoxy derivative, and iii) esters of substituted and unsubstituted benzoic acids for example, phenyl salicylate, 4-tert-butylphenyl-salicilate, octylphenyl salicylate, dibenzoylresorcinol, bis-(4-tert-butylbenzoyl)-resorcinol, benzoylresorcinol, 2,4-di-tert-butyl-phenyl-3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate.

The composition can further comprise one or more anti-dripping agents, which prevent or retard the resin from dripping while the resin is subjected to burning conditions. Specific examples of such agents include silicone oils, silica (which also serves as a reinforcing filler), asbestos, and fibrillating-type fluorine-containing polymers. Examples of fluorine-containing polymers include fluorinated polyolefins such as, for example, poly(tetrafluoroethylene), tetrafluoroethylene/hexafluoropropylene copolymers, tetrafluoroethylene/ethylene copolymers, polyvinylidene fluoride, poly(chlorotrifluoroethylene), and the like, and mixtures comprising at least one of the foregoing anti-dripping agents. A preferred anti-dripping agent is poly(tetrafluoroethylene). When used, an anti-dripping agent is present in an amount of ranging from about 0.02 to about 2 weight percent, and more preferably from about 0.05 to about 1 weight percent, based on the total weight of the composition.

Dyes or pigments may be used to give a background coloration. Dyes are typically organic materials that are soluble in the resin matrix while pigments may be organic complexes or even inorganic compounds or complexes, which are typically insoluble in the resin matrix. These organic dyes and pigments include the following classes and examples: furnace carbon black, titanium oxide, zinc sulfide, phthalocyanine blues or greens, anthraquinone dyes, scarlet 3b Lake, azo compounds and acid azo pigments, quinacridones, chromophthalocyanine pyrrols, halogenated phthalocyanines, quinolines, heterocyclic dyes, perinone dyes, anthracenedione dyes, thioxanthene dyes, parazolone dyes, polymethine pigments and others.

The compositions may, optionally, further comprise other conventional additives used in polyester polymer compositions such as non-reinforcing fillers, stabilizers, mold release agents, plasticizers, and processing aids. Other ingredients, such as dyes, pigments, anti-oxidants, and the like can be added for their conventionally employed purposes.

The compositions can be prepared by a number of procedures. In an exemplary process, the polyester composition, optional amorphous additives, impact modifier and filler and/or reinforcing glass is put into an extrusion compounder with resinous components to produce molding pellets. The resins and other ingredients are dispersed in a matrix of the resin in the process. In another procedure, the ingredients and any reinforcing glass are mixed with the resins by dry blending, and then fluxed on a mill and comminuted, or extruded and chopped. The composition and any optional ingredients can also be mixed and directly molded, e.g., by injection or transfer molding techniques. Preferably, all of the ingredients are freed from as much water as possible. In addition, compounding should be carried out to ensure that the residence time in the machine is short; the temperature is carefully controlled; the friction heat is utilized; and an intimate blend between the resin composition and any other ingredients is obtained.

Preferably, the ingredients are pre-compounded, pelletized, and then molded. Pre-compounding can be carried out in conventional equipment. For example, after pre-drying the polyester composition (e.g., for about four hours at about 120Â° C.), a single screw extruder may be fed with a dry blend of the ingredients, the screw employed having a long transition section to ensure proper melting. Alternatively, a twin screw extruder with intermeshing co-rotating screws can be fed with resin and additives at the feed port and reinforcing additives (and other additives) may be fed downstream. In either case, a generally suitable melt temperature will be about 230Â° C. to about 300Â° C. The pre-compounded composition can be extruded and cut up into molding compounds such as conventional granules, pellets, and the like by standard techniques. The composition can then be molded in any equipment conventionally used for thermoplastic compositions, such as a Newbury type injection molding machine with conventional cylinder temperatures, from about 230Â° C. to about 280Â° C., and conventional mold temperatures ranging from about 55Â° C. to about 95Â° C. The compositions provide an excellent balance of impact strength, and flame retardancy.

The molten mixture of the thermoplastic resin composition is formed into particulate form, example by pelletizing or grinding the composition. The composition of the present invention can be molded into useful articles by a variety of means by many different processes to provide useful molded products such as injection, extrusion, rotation, foam molding calender molding and blow molding and thermoforming, compaction, melt spinning form articles. The thermoplastic composition of the present invention has additional properties of good mechanical properties, color stability, oxidation resistance, good flame retardancy, good processability, i.e. short molding cycle times, thermal properties. Non limiting examples of the various articles that could be made from the thermoplastic composition of the present invention include electrical connectors, electrical devices, computers, building and construction, outdoor equipment. The articles made from the composition of the present invention may be used widely in houseware objects such as food containers and bowls, home appliances, as well as films, electrical connectors, electrical devices, computers, building and construction, outdoor equipment, trucks and automobiles.

Typically the additive is generally present in amount corresponding from about 0 to about 1.5 weight percent based on the amount of resin. In another embodiment the additive is generally present in amount corresponding from about 0.01 to about 0.5 weight percent based on the amount of resin.

The polyester composition of the present invention can be blended with conventional thermoplastics. Examples of materials suitable for use as thermoplastic material that can be blended with the polyester composition include, but are not limited to, amorphous, crystalline, and semi-crystalline thermoplastic materials such as: polyolefins (including, but not limited to, linear and cyclic polyolefins and including polyethylene, chlorinated polyethylene, polypropylene, and the like), polyesters (including, but not limited to, virgin polyethylene terephthalate, polyethylene terephthalate recycled from bottle scrap, polybutylene terephthalate, polycyclohexylmethylene terephthalate, poly(cyclohexanedimethylene cyclohexanedicarboxylate) and the like), polyamides, polysulfones (including, but not limited to, hydrogenated polysulfones, and the like), polyimides, polyether imides, polyether sulfones, polyphenylene sulfides, polyether ketones, polyether ether ketones, ABS resins, polystyrenes (including, but not limited to, hydrogenated polystyrenes, syndiotactic and atactic polystyrenes, polycyclohexyl ethylene, styrene-co-acrylonitrile, styrene-co-maleic anhydride, and the like), polybutadiene, polyacrylates (including, but not limited to, polymethylmethacrylate (PMMA), methyl methacrylate-polyimide copolymers, and the like), polyacrylonitrile, polyacetals, polycarbonates, polyphenylene ethers (including, but not limited to, those derived from 2,6-dimethylphenol and copolymers with 2,3,6-trimethylphenol, and the like), ethylene-vinyl acetate copolymers, polyvinyl acetate, liquid crystal polymers, ethylene-tetrafluoroethylene copolymer, aromatic polyesters, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene chloride, and tetrafluoroethylenes (e.g., Teflons) and mixtures, copolymers, reaction products, blends and composites comprising at least one of the foregoing polymers. In one embodiment, the polymer resin can be homopolymers or copolymers of one of polyolefins, polycarbonates, polyesters, polyphenylene ethers and styrenic polymers, or a mixture thereof. In another embodiment, the polymer resin comprises a polyolefin selected from the group consisting of polyethylene, polypropylene, polybutylene, homopolymers, copolymers and mixtures thereof. In yet another embodiment of the present invention, the polymer resin comprises polycarbonate and mixtures, copolymers, reaction products, blends and composites comprising polycarbonate.

In one embodiment, the method of incorporation of the unsaturation in the composition of the invention can be through either a masterbatch approach wherein the unsaturated diol content does not exceed 30 mole percent. In another embodiment, incorporation of unsaturation in the composition is through preparation of polyester by using required ratio of unsaturated diol to diols other than unsaturated diol, wherein the amount of unsaturated diol does not exceed 15 mole percent.

The method of blending can be carried out by conventional techniques. The production of the compositions may utilize any of the blending operations known for the blending of thermoplastics, for example blending in a kneading machine such as a Banbury mixer or an extruder. To prepare the resin composition, the components may be mixed by any known methods. In one embodiment of the present invention the thermoplastic composition could be prepared by a solution method. The solution method involves dissolving all the ingredients in a common solvent (or) a mixture of solvents preferably an organic solvent, which is substantially inert towards the polymer, and will not attack and adversely affect the polymer and either precipitation in a non-solvent or evaporating the solvent either at room temperature or a higher temperature. Some suitable organic solvents include ethylene glycol diacetate, butoxyethanol, methoxypropanol, the lower alkanols, chloroform, acetone, methylene chloride, carbon tetrachloride, tetrahydrofuran, and the like. In one embodiment of the present invention the non solvent is at least one selected from the group consisting of mono alcohols such as ethanol, methanol, isopropanol, butanols and lower alcohols with C1 to about C12 carbon atoms.

EXAMPLES

The following examples are included to provide additional guidance to those skilled in the art in practicing the claimed invention. The examples provided are merely representative of the work that contributes to the teaching of the present application. Accordingly, these examples are illustrative and are not intended to limit the invention, as defined in the appended claims, in any manner.

Preparation and Testing Procedures

The thermoplastic resin compositions were compounded at a temperature in the range of about 250-270Â° C. on a WP25 mm co-rotating twin screw extruder, yielding a pelletized composition. Compounding was carried out at a feed rate of about 15 kilogram per hour and a screw speed of about 300 rotations per minute. Flame bars were molded on 85T L&T Demag injection molding machine and tested in accordance with UL94 test at 0.8 mm thickness. The polymer samples were then tested for various properties like flammability and mechanical properties. The flame properties were also tested on 1 mm thick samples using the UL94 test procedure. The tensile modulus, strength and elongation at break of the samples were determined in accordance with ISO 527 test protocol. The formulation components are given in Tables below.

Materials

TABLE 1Details of ingredients used examplesAbbreviationPBTPolybutyleneterephthalatePBT-B1Polybutyleneterephthalate with 6% butenediolPBT-B2Polybutyleneterephthalate with 8% butenediolExolit OP950Zinc diethylphosphinate from ClariantMC-25Melamine cyanurate from DSM MelampurADR4368Epoxy compound from Johnson PolymersTSANAntidrip from GE Advanced MaterialsIrganox 1010Antioxidant from Ciba Speciality Chemicals

Formulations Tested/Results and Comparative Examples

The actual compositions used and the comparative examples along with the results are shown below in Tables 2 and 3.

TABLE 2C. Ex. 1C. Ex. 2C. Ex. 3Ex. 1Ex. 2PBT (%)45.8545.6000PBT-B1(%)00045.60PBT-B2(%)0045.85045.85ADR 4368(%)00.2500.250.25Exolit OP950(%)13.513.513.513.513.5MC(%)1010101010Glass Fiber(%)3030303030Antidrip(%)0.50.50.50.50.5Antioxidant(%)0.150.150.150.150.15Rating UL94 @ 1 mmNRV2V1V1V0Tensile Modulus (GPa)10.210.6â€”10.3â€”Tensile Strength (MPa)85.383.6â€”81.0â€”Elongation at break(%)1.731.64â€”1.16â€”
NR = no rating

As seen in Table 2, replacement of regular PBT with an unsaturated PBT i.e butenediol modified PBT improves the flame resistance or flame retardant property of the polyester composition with retention of mechanical properties (Ex. 1 and C. Ex. 1 and C. Ex. 2). Addition of the organic compound containing at least one carboxyl reactive group to PBT-B1 enhances the flame resistance property (Ex. 2 and C. Ex. 3).

TABLE 3C. Ex. 4C. Ex. 5C. Ex. 6Ex. 3PBT57.6557.400PBT-B1 (6% butene)0057.6557.4ADR 436800.2500.25Brominated PC8.58.58.58.5Sb2O33.23.23.23.2Glass Fiber30303030Antidrip0.50.50.50.5Antioxidant0.150.150.150.15Rating UL94 @ 1 mmV2V2V0V0Rating UL94 @ 0.8 mmV2V2V2V0Tensile Modulus (GPa)9.9109.610.1Tensile Strength (MPa)133139140145Elongation at break (%)2.62.52.52.5

From Table 3 it can be seen that an improvement in flame resistance performance both at 1 mm and 0.8 mm was obtained with retention of mechanical properties, when a combination of polyester containing unsaturation and the carboxyl reactive epoxy compound is employed, see Ex. 3. Addition of carboxy reactive organic compound (an epoxy compound) to a polyester having no unsaturation does not result in improvement of the flame resistance property (C. Ex. 4 and C. Ex. 5). However, it is noticed that addition of unsaturation to polyester improves flame performance at 1 mm (C. Ex. 4 and C. Ex. 6).

While the invention has been illustrated and described in typical embodiments, it is not intended to be limited to the details shown, since various modifications and substitutions can be made without departing in any way from the spirit of the present invention. As such, further modifications and equivalents of the invention herein disclosed may occur to persons skilled in the art using no more than routine experimentation. All Patents and published articles cited herein are incorporated herein by reference.