CA2026383A1

CA2026383A1 - Impact modified thermoplastic polyurethane-polyester molding materials and preparation thereof

Info

Publication number: CA2026383A1
Application number: CA 2026383
Authority: CA
Inventors: Dietrich Lausberg; Rolf Steinberger
Original assignee: Individual
Current assignee: BASF SE
Priority date: 1989-09-28
Filing date: 1990-09-27
Publication date: 1991-03-29
Also published as: DE3932360A1; EP0420017A3; JPH03166257A; EP0420017A2; FI904688A0

Abstract

- 28 - O.Z. 0050/41134 Abstract of the Disclosure: Impact modified thermoplastic polyurethane-polyester molding materials containing, based on 100 parts by weight of (A) to (C), A) from 30 to 90 parts by weight of at least one thermoplastic polyurethane elastomer, B) from 5 to 65 parts by weight of at least one thermo-plastic polyester, preferably a polyalkylene tereph-thalate, and C) from 5 to 30 parts by weight of at least one ethylene copolymer preferably based on Ca) ethylene Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl (meth)-acrylate, and Cc) at least one further monomer which contains a group which is reactive toward the thermo-plastic polyurethane elastomer (A) or the thermoplastic polyester (B) and D) from 0 to 63 % by weight of at least one fibrous or particulate filler and E) from 0 to 10 % by weight of at least one assistant, the weight percentages being based on the weight of (A) to (C), are prepared by homogenizing the formative components at 190-250°C.

Description

:- ` ` 2026383 O.Z. 0050/41134 mpact modLfied thermopla~tic polyurethane-~olYe~ter molding material~ and ~reparation thereo~
The present invention relates to Lmpact modified thermoplastic polyurethane-polyester molding materials which contain A) at least one thermoplastic polyurethane elastomer, hereinafter abbreviated to TPU, B) at least one thermoplastic polyester, hereinafter abbreviated to PES, and C) at least one ethylene copolymer advantageously based on Ca) ethylene, Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl ~meth)-acrylate, and Cc) at least one further monomer which contains a group which is reactive toward the TPU (A) or PES (B), and optionally D) fillers and/or E) assistant~.
Thermoplastic molding materials from TPU and PES
are known.
Materials of improved low temperature impact toughnes~ as described in ~E-A-26 46 647 (GB 1 513 197) consist of an intimate mixture of from 50 to 75 part~ by weight of TPU and from 25 to 50 % by weight of a poly-butylene terephthalate, also known as PBT. CA-A-l 111 984 likewise de~cribes TPU/PBT materials which, however, based on the total weight, con~ist of from 5 to 95 ~ by weight of TPU and from 95 to 5 % by weight of PBT. The~e TPU/PBT molding materials, however, have the disadvantage of inadequate notched impact strength and insufficient multiaxial toughness, in particular at low temperatures.
TPU mixtures which contain processing aids and are composed of from 40 to 100 % by weight of TPU, from 0 to 60 % by weight of a thermoplastic polymer selected 202~83 - 2 - O.Z. OOgO/41134 from the group consisting of polycarbonates, polyoxy-methylenes, acrylonitrile-butadiene-styrene graftcopoly-mers, PBT, polyethylene terephthalate and mixture~
thereof, and from 0.5 to 10 % by weight, based on the S total weight of TPU and the other thermoplastic polymer, of a polyacrylate-based processing aid selected from the group consisting of a methyl methacrylate homopolymer, a methyl methacrylate/n-butyl methacrylate or methyl methacrylate/ethyl acrylate copolymer and a terpolymer of methyl methacrylate, n-butyl acrylate and styrene are known from US-A-4 179 479. However, these materials based on TPU, PBT or polyethylene terephthalate and the essen-tially linear (meth)acrylate homopolymer or copolymer possess unsatisfactory toughness at low temperatures and are difficult to process.
It is an ob~ect of the present invention to remove the aforementioned disadvantages as completely as possible and to develop TPU/PES molding materials which possess a distinctly improved low temperature toughness and are easy to process into shaped articles.
We have found, surprisingly, that this ob~ect is achieved by introducing at least one ethylene copolymer (C) having a specific structure into TPU/PES molding materials of defined composition.
The present invention accordingly provides impact modified thermoplastic polyurethane-polyester molding materials which contain or preferably consist of, based on 100 parts by weight of (A) to (C), A) from 30 to 90 parts by weight, preferably from 40 to 80 parts by weight, of at least one TPU (A), B) from 5 to 65 parts by weight, preferably from 10 to 60 parts by weight, of at least one P~S (B) and C) from 5 to 30 parts by weight, preferably from 8 to 25 parts by weight, of at least one ethylene copoly-mer (C) and also, ba~ed on the total weight of (A) to (C), D) from 0 to 60 % by weight, preferably from 2 to 50 %

20263~3 - 3 - O.Z. 0050/41134 by weiqht, of at least one fibrous or particulate filler and E) from 0 to 10 % by weight, preferably from 0 to 5 by weight, of at least one assistant.
The present invention further provides a proce~
for preparing the TPU/PES molding materials accordLng to the present invention by homogenizing the formative components at 190-250C in a suitable mixing apparatus.
As mentioned, the TPU/PES molding materials according to the present invention have very good low temperature toughness. The increased fluidity also appreciably improves their processibility, so that the molding materials are easily convertible into shaped articles by the in~ection molding technique. Further lS advantageous properties are for example: short cycle times in the production of shaped articles, their good demoldability and excellent resistance to organic sol-vents.
The TPUs (A) usable for preparing the TPU/PES
molding materials according to the present invention correspond to the prior art and can be prepared by reacting a) organic, preferably aromatic, diisocyanates, in particular 4,4'-diphenylmethane diisocyanate, with b) polyhydroxy compounds, preferably e~sentially linear polyhydroxy compounds, having molecular weights of from 500 to 8000, in particular polyalkylene glycol polyadipate~ having from 2 to 6 carbon atoms in the alkylene moiety and molacular weights of from 500 to 6000 or hydroxyl-containing polytetrahydrofuran having a molecular weight of from 500 to 8000, and c) diol~ a~ chain extender~ having molecular weights of from 60 to 400, in particular 1,4-butanediol, in the presence of d) catalystY and optionally e) aids and/or f) additive~

- 4 ~ O.Z. 0050/41134 at elevated temperatures.
The TPU-forming components (a) to (d) and option-ally (e) and/or (f) may be described in detail as follows:
a) Suitable organic diisocyanate~ (a) are for example aliphatic, cycloaliphatic and preferably aromatic diisocyanateR. Specific examples are: aliphatic diiso-cyanates such as 1,6-hexamethylene diisocyanate, 2-methyl-1,5-pentamethylene dii~ocyanate, ~-ethyl-1,4-butylene diisocyanate and mixtures of at least two ofsaid aliphatic diisocyanates, cycloaliphatic diisocyan-ates such as isophorone diisocyanate, 1,4-cyclohexane diisocyanate, l-methyl-2,4-cyclohexane diisocyanate and l-methyl-2,6-cyclohexane dii~ocyanate and the correspond-ing isomeric mixtures, 4,4'-, 2,4'- or 2,2~-dicyclohexyl-methane diisocyanate and the correQponding isomeric mixtures and preferably aromatic diisocyanates such a~
2,4-toluylene diisocyanate, mixtures of 2,4- and 2,6-toluylene diisocyanate, 4,4'-, 2,4'- and 2,2'-diphenyl-methane diisocyanate, mixtures of 2,4'- and 4,4~-di-phenylmethane diisocyanate, urethane-modified liquid 4,4~- and/or 2,4'-diphenylmethane diisocyanates, 4,4'-diisocyanato-1,2-diphenylethane, mixtures of 4,4'-, 2,4'-and 2,2~-diisocyanato-1,2-diphenylethane, preferably those having a 4,4'-diisocyanato-1,2-diphenylethane content of at least 95 % by weight, and 1,5-naphthylene diisocyanate. Preference is given to using diphenyl-methane diisocyanate i omer mixture~ having a 4,4'-diphenylmethane diisocyanate content of greater ~han 96 %
by weight and in particular essentially pure 4,4'-di-phenylmethane diisocyanate.
The organic diisocyanates may be replaced to a minor extent, for example in an amount of up to 3 mol %, preferably up to 1 mol %, based on the organic diisocyan-ate, by a trifunctional or more highly functional poly-isocyanate, the amount of which, however, must be limited in such a way a~ to produce a still thermoplastic poly-2026~3 O.Z. 0050/41134 urethane. A ma~or amount of such tri- or more highly functional isocyanates is advantageously balanced by the inclusion of less than difunctional compounds having reactive hydrogen atoms, in order that excessive chemical crosslinking of the polyurethane may be avoided. Example~
of more than difunctional isocyanates are mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates, so-called crude MDI, and liquid 4,4~-and/or 2,4'-diphenylmethane diisocyanate modified with isocyanurate, urea, biuret, allophanate, urethane and/or carbodiimide groups.
Suitable monofunctional compounds having a reactive hydrogen atom which are also usable as molecular weight regulators are for example: monoamines such as butylamine, dibutylamine, octylamine, stearylamine, N-methylstearylamine, pyrrolidone, piperidine and cyclo-hexylamine and monoalcohols such as butanol, amyl alcohol, 1-ethylhexanol, octanol, dodecanol, cyclohexanol and ethylene glycol monoethyl ether.
b) Preferred polyhydroxy co~pounds (b) having molecular weights of from 500 to 8000 are polyetherols and in particular polyesterols. However, it is also possible to u~e other hydroxyl-containing polymers containing ether or ester group~ as bridge members, for example polyacetals, such as polyoxymethylenes and in particular water-insoluble formals, eg. polybutanediol formal and polyhexanediol formal, and polycarbonates, in particular those formed from diphenyl carbonate and 1,6-hexanediol, prepared by transesterification. The poly-hydroxy compound~ must be at least predominantly linear,ie. difunctional within ths meaning of the i~ocyanate reaction. The polyhydroxy compound~ mentioned may be used as individual components or in the form of mixtures.
Suitable polyetherols can be prepared from one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene moiety in a conventional manner, for example by anionic polymerization with alkali metal hydroxide~, 20263~3 - 6 - O.Z. OOSO/41134 such as sodium hydroxide or pota3sium hydroxide, or alkali metal alcoholates, ~uch as sodium methoxide, sodium ethoxide, potassium ethoxide or potassium isoprop-oxide, as catalysts and in the presence of at least one initiator molecule which contains 2 or 3, preferably 2 reactive hydrogen atoms, or ~y cationic polymerization with Lewi~ acids, such as antimony pentachloride, boron fluoride etherate, etc. or bleaching earth, as catalysts.
Preferred alkylene oxides are for example tetra-hydrofuran, 1,3-propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide and in particular ethylene oxide and 1,2-propylene oxide. The alkylene oxides may be used indi-vidually, alternately in succession or as mixtures.
Suitable initiator molecules are for example: water, organic dicarboxylic acids, such as succinic acid, adipic acid and/or glutaric acid, alkanolamines, such as ethan-olamine, N-alkylalkanolamines, N-alkyldialkanolamines, eg. N-methyl- and N-ethyl-diethanolamine, and preferably dihydric alcohols which may contain ether linkages, eg.
ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butane-diol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, 2-methyl-1,5-pentanediol and 2-ethyl-1,4-butanediol. The initiator molecules may be used individually or as mixtures.
Preference is given to using polyetherols from 1,2-propylene oxide and ethylene oxide in which more than 50 %, preferably from 60 to 80 ~, of the OH groups are primary hydroxyl groups and where at lea~t some of the ethylene oxide units are present a~ a terminal block.
Such polyethero}~ can be obtained by, for example, polymerizing onto the initiator molecule fir~t the 1,2-propylene oxide and then the ethylene oxide, or first the entire 1,2-propylene oxide mixed with ~ome of the ethyl-ene oxide and then the remainder of the ethylene oxide, or step by step first some of the ethylene oxide, then the entire 1,2-propylene oxide and then the remainder of tha ethylene oxide.

202~3~3 - 7 - O.Z. 0050/41134 Other preferred possibilitie~ are the hydroxyl-containing polymerization products of tetrahydrofuran.
The essentially linear polyetherols have mole-cular weights of from 500 to 8000, preferably from 600 to 6000, in particular from 800 to 3500, the polyoxytetra-methylene glycols preferably having molecular weights of from 500 to 2800. They can be used not only individually but also in the form of mixtures with one another.
Suitable polyesterols may be prepared for example from dicarboxylic acids of from 2 to 12, preferably from 4 to 6, carbon atoms and polyhydric alcohols. Suitable dicarboxylic acids are for example: aliphatic dicar-boxylic acids, such as succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid and ~ebacic acid, and aromatic dicarboxylic acids, such a~ phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used individually or as mixtures, for example in the form of a mixture of succinic acid, glutaric acid and adipic acid. To prepare the poly-esterols it may be advantageous to use instead of the dicarboxylic acids the corresponding dicarboxylic acid derivatives, such as dicarboxylic monoesters or diesters having from 1 to 4 carbon atoms in the alcohol moiety, dicarboxylic anhydrides or dicarbonyl dichlorides.
Examples of polyhydric alcohol~ are glycols of from 2 to 10, preferably from 2 to 6, carbon atoms, such as ethyl-ene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-di-methylpropane-1,3-diol, 1,3-propanediol and dipropylene glycol. Depending on the properties which are desired, the polyhydric alcohols may be used alone or optionally mixed with one another.
It i8 also possible to use esters of carbonic acid with the diols mentioned, in particular those having from 4 to 6 carbon atoms, such as 1,4-butanediol and/or 1,6-hexanediol, condensation products of ~-hydroxycar-boxylic acids, eg. w-hydroxycaproic acid, and preferably - 8 - o.z 0050/41134 polymer~zation produ~tY of lactones, for example ~ubsti-tuted or unsubstituted ~-caprolactone~.
Preferred polyesterols are ethanediol poly-adipates, 1,4-butanediol polyadipates, ethanediol/1,4-butanediol polyadipates, 1,6-hexanediol/neopentylglycol polyadipates, 1,6-hexanediol/1,4-butanediol polyadipates and polycaprolactones.
The polyesterols have molecular weights of from 500 to 6000, preferably from 800 to 3500.
c) Suitable chain extenders (c) having molecular weights of from 60 to 400, preferably from 60 to 300, are preferably aliphatic diols of from 2 to 12 carbon atoms, preferably of 2, 4 or 6 carbon atoms, eg. ethanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol and in particular 1,4-butanediol. However, it is also pos-sible to use diesters of terephthalic acid with glycols of from 2 to ~ carbon atoms, eg. bisethylene glycol terephthalata, 1,4-butanediol terephthalate, and hydroxy-alkylene ethers of hydroquinone, eg. 1,4-di-(~-hydroxy-ethyl)-hydroquinone, and also polytetramethylene glycols having molecular weights of from 162 to 378.
To ~et the hardne3s and the melt flow index, the formative components can be varied within relatively wide molar ratios bearing in mind that the hardness and melt viscosity increase with an increasing level of chain extenders (c) while the melt flow index decrea3es.
To prepare relatively soft TPUs (A), for example those having a Shore A hardnes~ of less than 95, prefer-ably from 95 to 75, it is advantageous for exhmple to use the es~entially difunctional polyhydroxy compounds (b) and the diols (c) in a molar ratio of from 1:1 to 1:5, preferably from 1:1.5 to 1:4.5, 80 that the resulting mixture3 of (b) and (c) have a hydroxy equivalent weight of greater than 200, in particular from 230 to 450, while harder TPU8 (A), for example those having a Shore A
hardnes~ of greater than 98, preferably from 55 to 75 Shore D, are prepared u~ing molar ratios of (b):(c) _ g _ O.Z. 0050/41134 within the range from 1:5.5 to 1:15, preferably from 1:6 to 1:12, so that the re~ulting mixtures of (b) and (c) have a hydroxy equivalent weight of from 110 to 200, preferably from 120 to 180.
d) Suitable catalysts, in particular for the reac-tion between the NCO groups of the diisocyanates (a) and the hydroxyl groups of the formative components (b) and (c), are the customary tertiary amines, such as triethyl-amine, dimethylcyclohexylamine, N-msthylmorpholine, N,N~-dimethylpiperazine, diazabicyclo[2.2.2]octane and the like, and in particular organic metal compounds such as titanic esters, iron compounds, tin compounds, eg. ~in diacetate, tin dioctanoate, tin dilaurate or the tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate, dibutyltin dilaurate and the like.
The catalysts are customarily u~ed in amounts of from 0.001 to 0.1 part by weight per 100 parts by weight of the mixture of polyhydroxy compounds (b) and diols (c).
In addition to catalysts, the formative compo-nents may also contain aids (e) and/or additives (f).
Examples are lubricants, inhibitors, stabili~ers against hydrolysis, light, heat or discoloration, flame retar-dants, dyes, pigments, inorganic and/or organic fillers and reinforcing agents.
The aids (e) and/or additives (f) may be intro-duced into the formative components or into the reaction mixture for preparing the ~PUs (A). Alternatively, the aids (e) and/or additives (f), which may be identical to the assistant (E), may be mixed with the TPU (A), the PES
(B) and/or the ethylene copolymer (C) and then melted, or they are incorporated directly into the melt of com-ponents (A), (B) and (C). The latter method is also adopted in particular for incorporating the fibrous and/or particulate fillers (D).
Whera, in what follows, no details are provided concerning the usable aids or additives, they can be gathered from the relevant technical literature, for - 10 - O.Z. 0050/41134 example J.H. Saunders and K.C. Frisch's monograph, High Polymers, volume XVI, Polyurethanes, parts 1 and 2 (Interscience Publishers 1962 and 1964 respectively), Kunststoff-Handbuch, volume 7, Polyurethane~, 1st and 2nd editions (Carl Hanser Verlag 1966 and 1983 respectively), or DE-A-2,901,774.
To prepare the TPUs (A), the formative components (a), (b) and (c) are made to react in the presence of a catalyst (d) and in the presence or absence of aids (e) and/or additives (f) in such amounts that the equivalence ratio of the diisocyanate NCO groups to the total number of hydroxyl groups of components (b) and (c) is from 0.95 to 1.10:1, preferably 0.98 to 1.08:1, in particular approximately 1.0 to 1.05:1.
The TPUs (A) which are usable according to the present invention and which customarily contain from 8 to 20 % by weight, preferably from 8 to 16 % by weight, based on the total weight, of urethane groups and have a melt flow index at 210C of from 500 to 1, preferably from 100 to 1, can be prepared by the extruder technique or preferably the belt technique by batchwi~e or con-tinuous mixing of formative components (a) to (d) and optionally (e) and/or (f~, fully reacting the mixture in an extruder or on a support belt at from 60 to 250C, preferably at from 70 to 150C, and then granulating the resulting TPUs (A). It may be advantageous to heat the resulting TPU (A) at from 80 to 120C, preferably at from 100 to 110C, for a period of from 1 to 24 hour3 before further processing into the TPU/PES molding materials according to the present invention.
The TPUs (A) are, as mentioned, preferably prepared by the belt technique. To this end, the forma-tive components (a) to (d) and optionally (e) and/or (f) are continuously mixed with the aid of a mixing head at above the melting point of formative components (a) to (c). The reaction mixture is discharged onto a support, preferably a conveyor belt, for example a metal belt, and 202~383 ~ O.Z. 0050/41134 i~ passed at 1-20 m/min, preferably 4-10 m~min, through a hot zone from 1 to 20 m, preferably from 3 to 10 m, in length. The temperature in the hot zone is 60-200C, preferably 80-180C. Depending on the diisocyanate content of the reaction mixture, the reacSion is con-trolled by cooling or heating in such a way that at least 90 %, preferably at least 98 %, of the isocyanate groups of the diisocyanates react and the reaction mixture solidifies at the chosen reaction temperature. Owing to the free isocyanate groups in the solidified reaction product, which based on the total weight are within the range from O.OS to 1 % by weight, preferably from 0.1 to 0.5 % by weight, the TPUs (A) obtained have a very low melt vi~cosity or a high melt flow index.
B) Formative component (B) of the TPU/PES molding materials according to the present invention comprises, as mentioned, an amount, based on 100 parts by weight of (A), (B) and (C), of from 5 to 65 parts by weight, preferably from 10 to 60 parts by weight, in particular 12 to 50 parts by weight, of one or more thermoplastic polye~ters. Polyesters ~uitable for this purpose are described in the literature. They contain in the ~olycon-den~ate main chain at least one aromatic ring derived from an aromatic dicarboxylic acid. The aromatic ring may also be sub~tituted, for example by halogen, eg. chlorine or bromine, or/and by linear or branched alkyl, prefer-ably of from l to 4 carbon atoms, in particular of 1 or 2 carbon atoms, eg. methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl or tert-butyl.
The polyesters can be prepared by polycondens-ation of aromatic dicarboxylic acids or mixture~ of aromatic and aliphatic and/or cycloaliphatic dicarboxylic acids and the corresponding ester-forming derivatives, for example dicarboxylic anhydrides, monoester~ and/or diester~ having advantageously not more than 4 carbon atoms in the alcohol moiety, with aliphatic dihydroxy compounds at elevated temperature~, for example at from 20263~3 - 12 - O.Z. 0050/41134 160 to 260C, in the presence or absence of e~terifica-tion catalysts.
The preferred aromatic dicarboxylic acids are the naphthalenedicarboxylic acids, i~ophthalic acid and in particular terephthalic acid or mixtures of these dicarb-oxylic acids. Ifmixtures of aromatic and (cyclo)aliphatic dicarboxylic acids are used, up to 10 mol ~ of the aromatic dicarboxylic acids may be replaced by aliphatic and/or cycloaliphatic dicarboxylic acids of advantage-ously 4-14 carbon atoms, eg. succinic, adipic, azelaic, sebacic or dodecanedioic acid and/or cyclohexanedicar-boxylic acid.
The preferred aliphatic dihydroxy compounds are alkanediols of from 2 to 6 carbon atoms and cycloalkane-diols of from 5 to 7 carbon atom~. Specific examples of preferred aliphatic dihydroxy compounds are 1,2-ethane-diol, 1,4-butanediol, 1,6-hexanediol, neopentylglycol and 1,4-cyclohexanediol and mixtures of at least two of said diols.
Particularly suitable PES's (B) are specifically the polyalkylene terephthalates of alkanediols of from 2 to 6 carbon atom~, 80 that polye~hylene terephthalate and in particular polybutylene terephthalate are preferred.
The relative vi~cosity of the PES's (B) is in 2S general within the range from 1.2 to 1.8, measured in a 0.5 ~ strength by weight solution in 1:1 w/w phenol/o-dichlorobenzene at 25C.
C) The TPU/PES molding materials according to the present invention contain one or more ethylene copolymers (C) for improving the impect toughnes~, in particular at low temperatures, and increasing the fluidity as addi-tional formative component in an amount, based on 100 parts by weight of the molding materials consisting of (A), (B) and (C~, of from 5 to 30 parts by weight, especially from 8 to 30 parts by weight, in particular from 10 to 25 parts by weight.
Suitable ethylene copolymers (C) are 202~c~83 - 13 - O.Z. 0050/41134 advantageously ba~ed on Ca) ethylene, Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl (meth)acrylate, and Cc) at least one further monomer which contain~ a ~roup which is reactive towards the TPU (A) or PES (B).
Preference is given to using those ethylene copolymers (C) which based on the total weight contain in polymerized form:
Ca) ethylene units in an amount of from 50 to 98% by weight, preferably from 60 to 95% by weight, Cb) alkyl (meth)acrylate units in an amount of 1 to 45%
by weight, preferably from 10 to 35% by weight, and Cc) an amount of a further comonomer (Cc) having a group which is reactive toward TPU (A) or PES (B) ranging from 0.1 to 40~ by weight, preferably from l to 40%
by weight, in particular from 2 to 20% by weight.
Ca) Ethylene as monomer is sufficiently well known in polymer chemistry enough to make further remarks redundant.
Cb) The (meth)acrylic e~ters used as acrylates and/or methacrylate~ (Cb) having from 1 to 8 carbon atoms, preferably from 2 to 8 carbon atoms, in a linear or branched alkyl moiety are those where, in the ready-prepared ethylene copolymer (C), the ester groups of the polymerizable (meth)acrylate units react essen-tially not at all or only to a minor extent with the TPU (A) or PES (B) under the reaction conditions of formin~ TPU/PES molding material~. Specific examples are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-heptyl and n-octyl acrylates and methacrylates. The alkyl (meth)acrylates can be used indi~idually or in the form of mixtures. Preference is gi~en to using n-butyl and/or 2-ethylhexyl (meth)acrylate.
Cc) Suitable comonomerC (Cc) are olefinically 2026 38~`

- 14 - O.Z. 0050/41134 unsaturated monomers which are copolymerizable with ethylene and alkyl (meth)acrylates and contain a reactive group which, in the ready-prepared ethylene copolymer (C), reacts with the TPU (A) or PES (B) under the reaction conditions for forming TPU/PES
molding materials, the reaction taking place to such an extent that, after the reaction has ended, the degree o~ coupling to the TPU (A) and PES (B) i5 greater than 0.01, preferably within the range from 0.03 to 1, in particular from 0.05 to 0.8, the degree of coupling being defined here as the ratio of ethylene copolymer (C) not extractable with toluene from the TPU/PES molding material to the total amount of ethylene copolymer (C) used.
Examples of groups which are reactive with TPU (A) or PES (B) are sulfo, sulfonyl, oxazoline and epoxy groups, preferably carboxyl, tert~butyl carboxylate and carboxylic anhydride groups.
Suitable comonomers (Cc) for preparing the ethylene copolymers (C) are for example olefinically unsaturated monocarboxylic acids, eg. acrylic acid and methacrylic acid and the corresponding tert-butyl esters, eg. tert-butyl (meth)acrylate, olefinically unsaturated dicarboxylic acids, eg. fumaric acid and maleic acid, and the corresponding mono- and/or di-tert-butyl esters, eg.
mono- and di-tert-butyl fumarate and mono- or di-tert-butyl maleate, olefinically unsaturated dicarboxylic anhydride~, eg. maleic anhydride, sulfo- or sulfonyl-containing olefinically unsaturated monomers, eg. p-styrene~ulfonicacid,2-(meth)acrylamido-2-methylpropene-sulfonic acid or 2-sulfonyl (meth)acrylate, oxazolinyl-containing olefinically unsaturated monomers, eg. vinyl oxazolines and vinyl oxazoline derivatives, and olefini-cally unsaturated monomers which contain epoxy groups, eg. glycidyl (meth)acrylate or allyl glycidyl ether.
Particularly preferred comonomers (Cc) are acrylic acid, methacrylic acid, tert-butyl (meth)acrylate '~02~83 - 15 - O.Z. 0050/41134 and/or in particular maleic anhydride and also glycidyl methacrylate.
Said comonomers (Cc), like the alkyl (meth)acryl-ates, can be used individually or in the form of mixtures for preparing the ethylene copolymer (C).
The ethylene copolymers (C) can be prepared in a conventional manner, preferably by random copolymeriza-tion under high pressure, for example at from 200 to 4000 bar, and at elevated temperature, for example within the range from approximately 120 to 300C. Appropriate techniques are described in literature and patent publi-cation~.
~ he melt flow index of suitable ethylene copoly-mers (C) is advantageously within the range from 1 to 80 g/10 min, preferably from 2 to 25 g/10 min (measured at 190C under a load of 2.16 kg in accordance with German Standard Specification DIN 53 735).
The impact modified thermoplastic TPU/PES molding materials according to the present invention may in addition to the e ~ential components (A), (B) and (C) optionally also contain fibrous and/or particulate fillers (D) and/or assistant3 (E).
D) The proportion of filler (D) is customarily from 0 to 60 % by weight, preferably from 2 to 50 % by weight, in particular from 5 to 30 % by weight, based on the total weight of components (A) to (C).
Suitable particulate fillers are for example:
organic fillers, such a~ carbon black, chlorinated polyethylenes and melamine, and inorganic fillers such as wollastonite, calcium carbonate, magnesium carbonate, amorphous silica, calcium ~ilicate, calcium metasilicate, quartz powder, talc, kaolin, mica, feldspar, glass spheres, silicon nitride, boron nitride and mixtures thereof.
Particularly suitable reinforcing fillers which are therefore preferred are fiber~, for example carbon fibers and in particular gla~s fiber~, with or without an 202~38'~
- 16 - O.Z. 0050/41134 adhesion promoting or/and size finish. Suitable glas~
fibers, which are also for example in the form of glass weaves, mats, webs and/or preferably glass filament rovings or chopped glass filament formed from low-alkali E-glasses from 5 to 200 ~m, preferably from 6 to 15 ~m, in diameter, generally have a mean fiber length of from O.05 to 1 mm, preferably from 0.1 to 0.5 mm, after incorporation into the TPU/PES molding materials.
Of the aforementioned particulate or fibrous reinforcing fillers, glass fibers in particular are advantageous, in particular when a high heat resistance or very high stiffness is required.
E) As mentioned, the TPU/PES molding materials according to the present invention may also contain assistants (E). The assistants can be identical to the customary aids (c) or additives (f) used for preparing TPUs and therefore already be present in the TPU (A). The proportion of assistant tE) is in general from 0 to 10 ~
by weight, preferably from 0 to 5 ~ by weight, based on the total weight of formative components (A) to (C). Such assistants are for example: nucleating agents, anti-oxidants, stabilizers, lubricants, demolding agents and dyes.
The nucleating agent used can be for example talc, calcium fluoride, sodium phenylphosphinate, alumi-num oxide or finely-divided polytetrafluoroethylene in an amount of up to S ~ by weight, based on the weight of formative components (A) to (C).
Suitable antioxidants and heat stabilizers which may ~e added to the TPU/PES molding materials are for example halides of metals of group I of the periodic table, for example halides of ~odium, potassium or lithium, alone or combined with copper(I) halides, eg.
chlorides, bromides or iodides, sterically hindered phenols, hydroquinones and also substituted compounds of the3e groups and mixtures thereof, which are preferably used in concentrations of up to 1 % by weight, based on 202~3~3 - 17 - o.z. 0050/41134 the weight of formative components (A) to (C).
Examples of W ~tabilizers are various substitu-ted resorcinols, salicylates, benzotriazoles and benzo-phenones and also sterically hindered amines, which in general are used in amounts of up to 2.0 ~ by weight, based on the weight of formative components (A) to (C).
Lubricants and demolding agents which in general are likewise added in amounts of up to 1 % by weight based on the weight of formative component~ (A) to (C), are Cl2-C3~-fatty acids, for example stearic acid~, fatty alcohol~, eg. stearyl alcohol, fatty acid esters or amides, eg. stearic esters and stearamides, and also the fatty acid esters of pentaerythritol and montan ester waxes.
It is also possible to add organic dyes, eg.
nigrosine, and pigment~, eg. titanium dioxide, cadmium sulfide, cadmium sulfide selenide, phthalocyanines, ultramarine blue or carbon black, in amount~ of for example up to 5 % by weight, based on formative compo-nent~ (A) to (C).
The impact modified thermoplastic TPU/PES molding materials according to the present invention can be prepared by any desired method for forming an essentially homogeneous composition from the TPU (A), the PES (B) and the ethylene copolymer (C) and optionally the fillers (D) and assi~tants (E). For example, the formative components (A) to (C) and optionally (D) and/or (E) can be mixed at from 0 to 150C, preferably at from 15 to 30Co and then melted, or the cGmponents can be mixed directly in the melt, Alternatively, (A) can be mixed with (C) or (B) with (C) and the~e mixtures be incorporated into (B) or (A) respectively, in which case (D) and/or (E) may already be present in one of the formative components (A) to (C) or may be added sub~equently.
The TPU/PES molding materials according to the pre~ent invention are prepared at from l90 to 250C, preferably from 210 to 240C, in the cour~e of a - 18 - O.Z. 0050t41134 residence time of from 0.S to 10 minutes, preferably of from 0.5 to 3 minutes, in for example the fluent, softened or preferably molten state of formative components (A) to (C), for example by ~tirring, rolling, kneading or preferably extruding, u~ing for example customary plasticating apparatus, eg. Brabender or Banbury mills, kneaders and extruders, preferably a twin-screw extruder or a mixing extruder for tran~fer molding.
In the most convenient and therefore preferable method of preparation, the TPU (A), the PES (B) and the ethylene copolymer (C) are mixed with or without (D) and/or (E) and melted together at 190-250C, preferably in an extruder, the melt ha~ incorporated into it any component (D) and/or (E) not introduced earlier and is then cooled, and the resulting TPU/PES molding material is comminuted.
The TPU/PES molding material~ obtained according to the present invention are easy to proces~ into shaped articles possessing good surface properties and improved impact toughness combined with high stiffness, in par-ticular at low temperatures, without separation into components (A) or (B) or (C) occurring in the melt or in the molding.
EXAMPLES
Impact modified thermoplastic TPU/PES molding materials according to the present invention are prepared using the following components:
A) Thermopla~tic polyurethane elastomers Al: TPU having a Shore D hardness of 69 prepared by reaction of a mixture of 0.5 mol of 1,4-butanediol polyadipate of molecular weight 2000 and 5.86 mol of 1,4-butanediol with 4,4'-diphenylmethane diisocyan-ate in an NCOsOH group ratio of l at 80-170C by the belt technique.
A2s TPU having a Shore D hardne~s of 74 prepared in the same way as A1 except that the NCOsOH group ratio used was 1.04.

- 19 - O. Z . 0050/41134 A3: TPU having a Shore A hardness of 90 prepared in the same way as Al, except that 1.7 mol of 1,4-butane-diol were used.
The above-described TPUS Al to A3 each contain, based on the alkanediol polyadipate welght, 1 % by weight of diisopropylphenylcarbodiimide a~ hydroly~is stabilizer.
A4: TPU having a Shore D hardness of 64 prepared by reaction of a mixture of 1 mol of polytetramethylene glycol of molecular weight lO00 and 3.87 mol of 1,4-butanediol with 4,4'-diphenylmethane dii~ocyanate in an NCO:OH group ratio of 1 a~ 90-170C by the belt technique.
B) Thermoplastic polyesters Bl: Polyethylene terephthalate having a relative visco-sity of 1.38 (measured on a 0.5 % strength by weight solution in 1:1 w/w phenol/o-dichloroben~ene).
B2: Polybutylene terephthalate having a relative visco-sity of 1.4, measured in the same way as B1.
C) Ethylene copolymer Cl: Terpolymer of ethylene, n-butyl acrylate and acrylic acid in a weight ratio of 65:30:5, prepared by high pressure polymerization as described in EP-A-0 106 999. The terpolymer had an NFI of 10 g/10 min, measured at 190C under a load of 2.16 kg in accord-ance with German Standard Specification DIN 53 735.
C2: Terpolymer of ethylene, n-butyl acrylate and maleic anhydride in a weight ratio of 65:35:0.5, prepared in the same way as Cl.
The terpolymer had an MFI of 12 g/10 min, measured at 190C under a load of 2.16 kg.
C3s Terpolymer of ethylene, n-butyl acrylate and gly-cidyl methacrylate in a weight ratio of 67:30:3, prepared as described under C1.
The terpolymer had an MFI of 10 g/10 min, measured at 190C under a load of 2.16 kg.
D) Fillers 202~383 - 20 - o.Z. 0050/41134 E-glass fibers in the form of a roving or in the form of chopped fiber. The gla~s fiber diameter was 10 ~m.
Preparation of the impact modified thermoplastic TPU/PES
molding materials COMPAR~TIVE ExAr~LEs I TO IV
To prepare the TPU/PES molding materials, com-ponents (A), (B) and (C) are intensively mixed at 23 C, the mixture is introduced into a twin-screw extruder and melted at 230C, and the melt i8 homogenized for 2 min-utes and then extruded into a water bath.
If E-glass fibers were used, these were incor-porated into the homogenized melt in the form of chopped fibers or rovings.
Following granulation and drying, the TPU/PES
molding materials were in~ection molded at 230C into test specimens on which measurements were carried out, without further aftertreatment, of the notched impact strength according to German Standard Specification DIN
53 453, the breaking extension according to German Standard Specification DIN 53 455 and the modulu~ of elasticity according to German Standard Specification DIN
53 457.
The identity and quantity of the TPUs (A), PES ' s (B) and ethylene copolymers (C) used and of any reinfor-cing fillers (D) and the mechanical propertie~ measured on the test specimen~ are summarized below in Table~ I
and II.
.

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Claims

1. An impact modified thermoplastic polyurethane-polyester molding material containing, based on 100 parts by weight of (A) to (C), A) from 30 to 90 parts by weight of at least one thermoplastic polyurethane elastomer (A), B) from 5 to 65 parts by weight of at least one thermo-plastic polyester (B) and C) from 5 to 30 parts by weight of at least one ethy-lene copolymer (C) and also, based on the total weight of (A) to (C), D) from 0 to 60 % by weight of at least one fibrous or particulate filler and E) from 0 to 10 % by weight of at least one assistant.

2. An impact modified thermoplastic polyurethane-polyester molding material consisting of A) from 30 to 90 parts by weight of at least one thermoplastic polyurethane elastomer (A), B) from 5 to 65 parts by weight of at least one thermo-plastic polyester (B) and C) from 5 to 30 parts by weight of at least one ethy-lene copolymer (C), the proportions by weight of (A) to (C) adding up to 100 parts by weight, and also, based on the total weight of (A) to (C), D) from 0 to 60 % by weight of at least one fibrous or particulate filler and E) from 0 to 10 % by weight of at least one assistant.

3. An impact modified thermoplastic polyurethane polyester molding material as claimed in claim 1, wherein the thermoplastic polyurethane elastomer (A) is prepared by reaction of a) an aromatic diisocyanate with b) a polyhydroxy compound having a molecular weight of from 500 to 8000 and c) a diol having a molecular weight of from 60 to 400 in an equivalence ratio of NCO groups of organic diiso-cyanate (a) to the total number of hydroxyl groups of - 24 - O.Z. 0050/41134 components (b) and (c) of from 0.95:1.0 to 1.1:1Ø

4. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the thermoplastic polyurethane elastomer (A) is prepared by reaction of a) 4,4'-diphenylmethane diisocyanate with b) an essentially linear polyhydroxy compound, prefer-ably a polyalkylene glycol polyadipate, having from 2 to 6 carbon atoms in the alkylene moiety and a molecular weight of from 500 to 6000 or a hydroxyl-containing polytetrahydrofuran having a molecular weight of from 500 to 8000, and c) 1,4-butanediol.

5. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim l, wherein the thermoplastic polyurethane elastomer (A) has a hardness within the range from Shore A 75 to Shore D 75 and is prepared by the belt technique.

6. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the thermoplastic polyester (B) has a relative viscosity within the range from 1.2 to 1.8, measured in a 0.5 %
strength by weight solution in 1:1 w/w phenol/o-dichloro-benzene at 25°C, and is prepared by polycondensation of an aromatic dicarboxylic acid with an alkanediol having 2 to 6 carbon atoms in the alkylene moiety.

7. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the thermoplastic polyester (B) is polyethylene tereph-thalate or preferably polybutylene terephthalate.

8. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the ethylene copolymer (C) is based on Ca) ethylene, Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl (meth)acrylate, and - 25 - O.Z. 0050/41134 Cc) at least one further monomer which contains a group which is reactive towards the thermoplastic polyure-thane elastomer (A) or the thermoplastic polyester (B).

9. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the ethylene copolymer (C) is based on Ca) ethylene, Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl (meth)acrylate, and Cc) at least one further monomer selected from the group consisting of the olefinically unsaturated monocar-boxylic acids and the corresponding tert-butyl esters, olefinically unsaturated dicarboxylic acids and the corresponding tert-butyl esters, olefini-cally unsaturated dicarboxylic anhydrides, sulfo-and sulfonyl-containing olefinically unsaturated monomers, oxazolinyl-containing olefinically un-saturated monomers and olefinically unsaturated monomers having epoxy groups.

10. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the ethylene copolymer (C) is based on Ca) ethylene, Cb) at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tart-butyl (meth)acrylate, and Cc) at least one further monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid and the tert-butyl esters of the aforementioned monocarboxylic and dicarboxylic acids and in particular maleic anhydride and also glycidyl methacrylate.

11. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the ethylene copolymer (C) is based on - 26 - O.Z. 0050/41134 Ca) from 50 to 98% by weight of ethylene, Cb) from 1 to 45% by weight of at least one alkyl (meth)acrylate having from 1 to 8 carbon atoms in a linear or branched alkyl moiety, but not tert-butyl (meth)acrylate and Cc) from 0.1 to 40% by weight of at least one further monomer which contains a group which is reactive towards the thermoplastic polyurethane (A) or the thermoplastic polyester (B) and is selected from the group consisting of the olefinically unsaturated monocarboxylic acids and the corresponding tert-butyl esters, olefinically unsaturated dicarboxylic acids and the corresponding tert-butyl esters, olefinically unsaturated dicarboxylic anhydrides, sulfo- and sulfonyl-containing olefinically un-saturated monomers, oxazolinyl-containing olefini-cally unsaturated monomers and olefinically un-saturated monomers having epoxy groups, the weight percentages being based on the total weight of monomers (Ca), (Cb) and (Cc) and always adding up to 100%
by weight.

12. An impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 1, wherein the ethylene copolymer (C) is based on Ca) from 50 to 98% by weight of ethylene, Cb) from 1 to 45% by weight of n-butyl (meth)acrylate and/or 2-ethylhexyl (meth)acrylate and Cc) from 0.1 to 40% by weight of (meth)acrylic acid, maleic anhydride and/or tert-butyl (meth)acrylate, the weight percentages being based on the total weight of monomers (Ca), (Cb) and (Cc) and always adding up to 100%
by weight.

13. A process for preparing an impact modified thermoplastic polyurethane polyester molding material, which comprises homogenizing, based on 100 parts by weight of (A) to (C), A) from 30 to 90 parts by weight of at least one - 27 - O.Z. 0050/41134 thermoplastic polyurethane elastomer (A), B) from 5 to 65 parts by weight of at least one thermo-plastic polyester (B) and C) from 5 to 30 parts by weight of at least one ethy-lene copolymer (C) and also, based on the total weight of (A) to (C), D) from 0 to 60 % by weight of at least one fibrous or particulate filler and E) from 0 to 10 % by weight of at least one assistant in a suitable mixing apparatus at 190-250°C for 0.5-10 minutes.

14. A process for preparing an impact modified thermoplastic polyurethane-polyester molding material as claimed in claim 13, wherein components (A) to (C) and optionally (D) and/or (E) are homogenized in a twin-screw extruder at 190-250°C for 0.5-10 minutes.