WO2004078844A1

WO2004078844A1 - Polyester blends with improved flexural rigidity

Info

Publication number: WO2004078844A1
Application number: PCT/EP2004/001674
Authority: WO
Inventors: Harald KRÖGER; Hans-Peter Vollmann
Original assignee: Basf Aktiengesellschaft
Priority date: 2003-03-04
Filing date: 2004-02-20
Publication date: 2004-09-16
Also published as: DE10309564A1

Abstract

The invention relates to thermoplastic moulding materials containing: between 0.1 and 50 wt. %, (in relation to the total weight of the components i) to ii)), of at least one aliphatic polyester or a polyester based on aliphatic and aromatic dicarboxylic acids and an aliphatic dihydroxy compound; ii) between 50 and 99.9 wt. %, (in relation to the total weight of the components i) to ii)) of at least one polyester based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compounds; and iii) in addition between 0 and 80 wt. %, (in relation to the total weight of the components i) and ii)) of conventional additives. The invention also relates to a method for producing thermoplastic moulding materials, to the use of thermoplastic moulding materials for producing blends, moulded parts, films, bristles, filaments, monofilaments, or fibres in addition to blends, moulded parts, films, bristles, filaments, monofilaments, or fibres containing thermoplastic moulding materials. The invention further relates to brushes, paintbrushes, cosmetic brushes, brooms, scrubbing brushes or toothbrushes comprising bristles, obtained from the thermoplastic materials and to filters, webs, braided fabric, yarns or textile fabric comprising filaments, monofilaments or fibres, obtained from said thermoplastic materials. The invention also relates to the use of aliphatic polyesters or polyesters based on aliphatic and aromatic dicarboxylic acids and an aliphatic dihydroxy compound for improving the flexural rigidity of polyesters based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compounds.

Description

Polyester blends with improved bending stiffness

description

The present invention relates to thermoplastic molding compositions containing

i) 0.1 to 50 wt .-%, based on the total weight of components i) to ii), of at least one aliphatic polyester or a polyester based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compound and

ii) 50 to 99.9% by weight, based on the total weight of components i) to ii) of at least one polyester based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compound and

iii) moreover 0 to 80% by weight, based on the total weight of components i) and ii), of conventional additives.

Furthermore, the present invention relates to processes for the production of thermoplastic molding compositions, the use of thermoplastic molding compositions for the production of blends, moldings, foils, bristles, filaments, monofilaments or fibers, and blends, moldings, foils, bristles, filaments, monofilaments or fibers containing thermoplastic molding compositions. Furthermore, the present invention relates to brushes, color brushes, cosmetic brushes, brooms, brushes or toothbrushes, including bristles, obtainable from the thermoplastic molding compositions, and also filters, tapes, braids, threads or fabrics, including filaments, monofilaments or fibers, obtainable from the thermoplastic molding compositions , Furthermore, the present invention relates to the use of aliphatic polyesters or polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compounds to improve the bending stiffness of polyesters based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compounds.

Thermoplastic molding compositions for the production of, for example, molded parts, films or fibers for a very wide variety of applications are known. Depending on the desired field of application, the properties of these molding compositions can be varied within a wide range by selecting different polymers or suitable additives. For example, it is desirable to produce blends, molded parts, foils, bristles, filaments, monofilaments or fibers from thermoplastic molding materials, the bending stiffness of which can be adjusted in a targeted manner with regard to the desired application and is as constant as possible under changing parameters during the desired application remains.

For example, for the manufacture of toothbrush bristles, for example those sold by the DuPont company under the Tynex ^® brand, molding compositions based on polyamides made from hexamethylene diamine and dodecanedioic acid, so-called PA 6.12, are used. However, the bristles produced from such molding compositions show a strong dependence of the bending stiffness on the amount of water absorbed during use.

Molding compositions based on polybutylene terephthalate, which are likewise used for the production of toothbrush bristles, have a bending stiffness which is almost independent of the water content, but this is undesirably high; that is, the bristles are stiffer than bristles from PA 6.12.

The present invention is therefore based on the object of providing thermoplastic molding compositions from which blends, moldings, foils, bristles, filaments, monofils or fibers can be produced, which have a bending stiffness which can be set in a targeted manner and is more independent of the water content than those which can be produced from known molding compositions Blends, molded parts, foils, bristles, filaments, monofilaments or fibers.

This object is achieved by the thermoplastic molding compositions defined at the outset, which are described in more detail below.

In principle, all aliphatic homo- and copolyesters and all polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compound can be considered as component i) for the production of the thermoplastic molding compositions according to the invention. Mixtures of several such polyesters are of course also suitable as component i).

Examples of suitable aliphatic polyesters i) from which the thermoplastic molding compositions according to the invention can be obtained are homopolymers of aliphatic hydroxycarboxylic acids, for example polylactides, or lactones, but also copolymers or block copolymers of different hydroxycarboxylic acids or lactones or mixtures thereof. These aliphatic polyesters can also contain diols and / or isocyanates as building blocks. In addition, the aliphatic polyesters can also contain building blocks which are derived from trifunctional or multifunctional compounds such as epoxides, acids or triols. The latter building blocks can be used individually or there several of them or together with the diols and / or isocyanates can be contained in the aliphatic polyesters.

Methods for producing aliphatic polyesters are known to the person skilled in the art. The aliphatic polyesters generally have molecular weights Mn in the range from 1,000 to 100,000 g / mol.

Polycaprolactone is one of the particularly preferred aliphatic polyesters.

Poly-3-hydroxybutanoic acid esters and copolymers of 3-hydroxybutanoic acid or their mixtures with 4-hydroxybutanoic acid and 3-hydroxyvaleric acid, in particular up to 30% by weight, preferably up to 20% by weight, of the latter acid are particularly preferred aliphatic polyesters. Suitable polymers of this type also include those with an R-stereospecific configuration, as are known from WO 96/09402. Polyhydroxybutanoic acid esters or their copolymers can be produced microbially. Methods for the production from various bacteria and fungi are e.g. Chem Tech. Lab. 39, 1112-1124 (1991), a method for producing stereospecific polymers is known from WO 96/09402.

Furthermore, block copolymers of the hydroxycarboxylic acids or lactones mentioned, their mixtures, oligomers or polymers can also be used.

Further aliphatic polyesters are those which are composed of aliphatic or cycloaliphatic dicarboxylic acids or their mixtures and aliphatic or cycloaliphatic diols or their mixtures. According to the invention, both statistical and block copolymers can be used.

The aliphatic dicarboxylic acids suitable according to the invention generally have 2 to 10 carbon atoms, preferably 4 to 6 carbon atoms. They can be both linear and branched. The cycloaliphatic dicarboxylic acids which can be used in the context of the present invention are generally those having 7 to 10 carbon atoms and in particular those having 8 carbon atoms. In principle, however, dicarboxylic acids with a larger number of carbon atoms, for example with up to 30 carbon atoms, can also be used.

Examples include: malonic acid, succinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, adipic acid, pimelic acid, acelaic acid, sebacic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid , 1, 3-Cyclohexanedicarboxylic acid, diglycolic acid, itacon acid, maleic acid and 2,5-norbornane dicarboxylic acid, among which adipic acid is preferred.

The ester-forming derivatives of the abovementioned aliphatic or cycloaliphatic dicarboxylic acids, which can also be used, are in particular the di-C 1 -C ₆ -alkyl esters, such as dimethyl, diethyl, di-n-propyl, di-isopropyl, di-n -butyl, di-iso-butyl, di-t-butyl, di-n-pentyl, di-iso-pentyl or di-n-hexyl esters. Anhydrides of the dicarboxylic acids can also be used.

The dicarboxylic acids or their ester-forming derivatives can be used individually or as a mixture of two or more thereof.

Examples of the suitable aliphatic polyesters are aliphatic copolyesters as described in WO 94/14870, in particular aliphatic copolyesters from succinic acid, its diesters or their mixtures with other aliphatic acids or diesters such as glutaric acid and butanediol or mixtures of this diol with ethylene glycol, propanediol or hexanediol or mixtures thereof.

Aliphatic polyesters of this type generally have molecular weights Mn in the range from 1000 to 100000 g / mol.

The aliphatic polyesters can likewise be random or block copolyesters which contain further monomers. The proportion of the other monomers is usually up to 10% by weight. Preferred comonomers are hydroxycarboxylic acids or lactones or mixtures thereof.

Mixtures of two or more comonomers and / or further building blocks, such as epoxides or polyfunctional aliphatic or aromatic acids or polyfunctional alcohols, can of course also be used to prepare the aliphatic polyesters.

Furthermore, the thermoplastic molding compositions according to the invention can be based on partially aromatic polyesters, ie on polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compound, as component i). According to the invention, this should also include polyester derivatives such as polyether esters, polyester amides or polyether ester amides. Suitable partially aromatic polyesters include linear non-chain extended polyesters (WO 92/09654). Chain-extended and / or branched partially aromatic polyesters are preferred. The latter are known from the documents mentioned at the outset, WO 96/15173 to 15176, 21689 to 21692, 25446, 25448 or WO 98/12242, to which explicit reference is made. Mixtures of different partially aromatic polyesters are also possible.

The particularly preferred partially aromatic polyesters include polyesters, which are essential components

A) an acid component

a1) 30 to 99 mol% of at least one aliphatic or at least one cycloaliphatic dicarboxylic acid or its ester-forming derivatives or mixtures thereof

a2) 1 to 70 mol% of at least one aromatic dicarboxylic acid or its ester-forming derivative or mixtures thereof and

a3) 0 to 5 mol% of a compound containing sulfonate groups,

B) a diol component selected from at least one C _{2 to} C ₁₂ alkanediol and at least one C ₅ to C ₁₀ cycloalkanediol or mixtures thereof

and, if desired, furthermore one or more components selected from

C) a component selected from

d) at least one dihydroxy compound of the formula I containing ether functions

HO - [(CH ₂ ) _n -O] _m -H (I)

where n is 2, 3 or 4 and m is an integer from 2 to 250

c2) at least one hydroxycarboxylic acid or formula IIa or IIb

( ^{| l} ) in which p is an integer from 1 to 1500 and r is an integer from 1 to 4, and G represents a radical which is selected from the group consisting of phenylene, - (CH ₂ ) _q -, where q is an integer from 1 to 5, -C (R) H- and -C (R) HCH ₂ , where R is methyl or ethyl

c3) at least one amino-C ₂ -C ₁₂ -alkanol or at least one amino-C ₅ -bis do-cycloalkanol or mixtures thereof

c4) at least one diamino-C to C ₈ alkane

c5) at least one 2,2'-bisoxazoline of the general formula III

where R ^{1 is} a single bond, a (CH ₂ ) _Z alkylene group, with z = 2, 3 or 4, or a phenylene group

c6) at least one aminocarboxylic acid selected from the group consisting of the natural amino acids, polyamides, obtainable by polycondensation of a dicarboxylic acid with 4 to 6 C atoms and a diamine with 4 to 10 C atoms, compounds of the formulas IV a and IVb

(IVa) (IVb) in which s is an integer from 1 to 1500 and 1 is an integer from 1 to 4, and T is a radical which is selected from the group consisting of phenylene, - (CH ₂ ) _U -, where u is an integer from 1 to 12, -C (R ² ) H- and -C (R ² ) HCH ₂ , where R ^{2 is} methyl or ethyl,

and polyoxazolines with the repeating unit V

in which R ^{3 represents} hydrogen, d-Ce-alkyl, Cs-Cs-cycloalkyl, unsubstituted or with C 1 -C ₄ -alkyl groups up to triple-substituted phenyl or tetrahydrofuryl, or mixtures of d to c6

and

D) a component selected from

d1) at least one compound with at least three groups capable of ester formation,

d2) at least one isocyanate

d3) at least one divinyl ether

or mixtures of d1) to d3).

In a preferred embodiment, the acid component A of the partially aromatic polyesters contains from 30 to 70, in particular from 40 to 60 mol% of a1 and from 30 to 70, in particular from 40 to 60 mol% of a2.

The aliphatic or cycloaliphatic acids and the corresponding derivatives a1 are those mentioned above. Adipic acid or sebacic acid or their respective ester-forming derivatives or mixtures thereof are particularly preferably used. Adipic acid or its ester-forming derivatives, such as its alkyl esters or mixtures thereof, are particularly preferably used.

Aromatic dicarboxylic acid a2 generally includes those with 8 to 12 carbon atoms and preferably those with 8 carbon atoms. Examples include terephthalic acid, isophthalic acid, 2,6-naphthoic acid and 1,5-naphthoic acid and ester-forming derivatives thereof. In particular, the di-C-rC ₆ alkyl esters, for example dimethyl, diethyl, di-n-propyl, di-iso-propyl, di-n-butyl, di-isobutyl, di-t- butyl, di-n-pentyl, di-iso-pentyl or di-n-hexyl esters. The anhydrides of dicarboxylic acids a2 are also suitable ester-forming derivatives.

In principle, however, aromatic dicarboxylic acids a2 with a larger number of carbon atoms, for example up to 20 carbon atoms, can also be used.

The aromatic dicarboxylic acids or their ester-forming derivatives a2 can be used individually or as a mixture of two or more thereof. Terephthalic acid or its ester-forming derivatives such as dimethylte- rephthalate.

The compound containing sulfonate groups is usually an alkali metal or alkaline earth metal salt of a sulfonate group-containing dicarboxylic acid or its ester-forming derivatives, preferably alkali metal salts of 5-sulphoisophthalic acid or mixtures thereof, particularly preferably the sodium salt.

According to one of the preferred embodiments, the acid component A contains from 40 to 60 mol% a1, from 40 to 60 mol% a2 and from 0 to 2 mol% a3. According to a further preferred embodiment, the acid component A contains from 40 to 59.9 mol% a1, from 40 to 59.9 mol% a2 and from 0.1 to 1 mol% a3, in particular from 40 to 59.8 mol -% a1, from 40 to 59.8 mol% a2 and from 0.2 to 0.5 mol% a3.

In general, the diols B are selected from branched or linear alkane diols having 2 to 12 carbon atoms, preferably 4 to 6 carbon atoms, or cycloalkane diols having 5 to 10 carbon atoms.

Examples of suitable alkanediols are ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,4-dimethyl-2-ethylhexane-1,3- diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 2,2,4-trimethyl- 1,6-hexanediol, in particular ethylene glycol, 1,3-propanediol, 1,4-butanediol and 2,2-dimethyl-1,3-propanediol (neopentyl glycol); Cyclopentanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol or 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Mixtures of different alkanediols can also be used.

Depending on whether an excess of acid or OH end groups is desired, either component A or component B can be used in excess. According to a preferred embodiment, the molar ratio of the components A to B used can be in the range from 0.4: 1 to 1.5: 1, preferably in the range from 0.6: 1 to 1.1: 1.

In addition to components A and B, the polyesters on which the molding compositions according to the invention are based can contain further components.

The dihydroxy compounds d used are preferably diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol and polytetrahydrofuran (poly-THF), particularly preferably diethylene glycol, triethylene glycol and polyethylene glycol, mixtures of these or compounds having different variables n also being used (see formula I), for example polyethylene glycol, which contains propylene units (n = 3) holds, for example, obtainable by polymerization according to known methods of first ethylene oxide and then with propylene oxide, particularly preferably a polymer based on polyethylene glycol, with different variables n, units formed from ethylene oxide predominating. The molecular weight (M _n ) of the polyethylene glycol is generally chosen in the range from 250 to 8000, preferably from 600 to 3000 g / mol.

According to one of the preferred embodiments, for example from 15 to 98, preferably 60 to 99.5 mol% of the diols B and 0.2 to 85, preferably 0.5 to 30 mol% of the dihydroxy compounds d, based on the molar amount of B and d, can be used for the production of the partially aromatic polyesters.

In a preferred embodiment, the hydroxycarboxylic acid c2) used is: glycolic acid, D-, L-, D-, L-lactic acid, 6-hydroxyhexanoic acid, their cyclic derivatives such as glycolide (1, 4-dioxane-2,5-dione) , D-, L-dilactide (3,6-dimethyl-1, 4-dioxane-2,5-dione), p-hydroxybenzoic acid and their oligomers and polymers such as 3-polyhydroxybutyric acid, polyhydroxyvaleric acid, polylactide (for example as EcoPLA ^® (Carrill)) as well as a mixture of 3-polyhydroxybutyric acid and polyhydroxyvaleric acid (the latter is available under the name Biopol ^® from Zeneca), particularly preferably the low molecular weight and cyclic derivatives thereof for the production of partially aromatic polyester.

The hydroxycarboxylic acids can be used, for example, in amounts of from 0.01 to 50, preferably from 0.1 to 40,% by weight, based on the amount of A and B.

Amino-C ₂ -C ₁₂ -alkanol or amino-C ₅ -C ₁₀ -cycloalkanol (component c3), which should also include 4-aminomethylcyclohexane-methanol, are preferably amino-C ₂ -C ₆ -alkanols such as 2-aminoethanol , 3-aminopropanol, 4-aminobutanol, 5-aminopentanol, 6-aminohexanol and amino-C ₅ -C ₆ -cyloalkanols such as aminocyclopentanol and aminocyclohexanol or mixtures thereof.

The diamino-d-Cs-alkane (component c4) is preferably a diamino-C ₄ -C ₆ -alkane such as 1,4-diminobutane, 1,5-diaminopentane and 1,6-diaminohexane (hexamethylene diamine, "HMD ").

According to a preferred embodiment, from 0.5 to 99.5 mol%, preferably 0.5 to 50 mol%, c3, based on the molar amount of B, and from 0 to 50, preferably from 0 to 35 mol% , c4, based on the molar amount of B, can be used for the production of the partially aromatic polyesters. The 2,2'-bisoxazolines c5 of the general formula III are generally obtainable by the process from Angew. Chem. Int. Edit, Vol. 11 (1972), pp. 287-288. Particularly preferred bisoxazolines are those in which R is a single bond, a (CH ₂ ) ₂ alkylene group with z = ₂ , 3 or 4, such as methylene, ethane-1, 2-diyl, propane-1,3-diyl, propane 1, 2-diyl, or a phenylene group. Particularly preferred bisoxazolines are 2,2'-bis (2-oxazolinyl), bis (2-oxazolinyl) methane, 1,2-bis (2-oxazolinyl) ethane, 1,3-bis (2-oxazolinyl) propane or 1 , 4-bis (2-oxazolinyl) butane, in particular 1,4-bis (2-oxazolinyl) benzene, 1,2-bis (2-oxazolinyl) benzene or 1,3-bis (2-oxazolinyl) benzene.

For the preparation of the partially aromatic polyesters, for example from 70 to 98 mol% of B, up to 30 mol% of c3 and 0.5 to 30 mol% of c4 and 0.5 to 30 mol% of c5, in each case based on the sum of the molar amounts of components B, c3, c4 and c5 can be used. According to another preferred embodiment, it is possible to use from 0.1 to 5, preferably 0.2 to 4% by weight of c5, based on the total weight of A and B.

Natural aminocarboxylic acids can be used as component c6. These include valine, leucine, isoleucine, threonine, methionine, phenylalanine, tryptophan, lysine, alanine, arginine, aspartic acid, cysteine, glutamic acid, glycine, histidine, proline, serine, tryosine, asparagine or glutamine.

Preferred aminocarboxylic acids of the general formulas IVa and IVb are those in which s is an integer from 1 to 1000 and t is an integer from 1 to 4, preferably 1 or 2 and T is selected from the group consisting of phenylene and - (CH ₂ ) _U -, where u is 1, 5 or 12.

Furthermore, c6 can also be a polyoxazoline of the general formula V. C6 can also be a mixture of different aminocarboxylic acids and / or polyoxazolines.

According to a preferred embodiment, c6 can be used in amounts of from 0.01 to 50, preferably from 0.1 to 40,% by weight, based on the total amount of components A and B.

Compounds d1 which contain at least three groups capable of ester formation are further components which can optionally be used for the production of the partially aromatic polyesters. The compounds d1 preferably contain three to ten functional groups which are capable of forming ester bonds. Particularly preferred compounds d1 have three to six functional groups of this type in the molecule, in particular three to six hydroxyl groups and / or carboxyl groups. Examples include:

Tartaric acid, citric acid, malic acid; Trimethylolpropane, trimethylolethane; pentaerythritol; polyether triols; glycerol;

trimesic; Trimellitic acid, anhydride; Pyromellitic acid, dianhydride and hydroxyisophthalic acid.

The compounds d1 are generally used in amounts of 0.01 to 15, preferably 0.05 to 10, particularly preferably 0.1 to 4 mol%, based on component A.

One or a mixture of different isocyanates is used as component d2. Aromatic or aliphatic diisocyanates can be used. However, higher functional isocyanates can also be used.

In the context of the present invention, an aromatic diisocyanate d2 includes above all

Toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthylene-1, 5-diisocyanate or xylylene diisocyanate are understood.

Among them, 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanate are particularly preferred as component d2. The latter diisocyanates are generally used as a mixture.

Tri (4-isocyanophenyl) methane is also suitable as the three-core isocyanate d2. The multinuclear aromatic diisocyanates are obtained, for example, in the production of mononuclear or dinuclear diisocyanates.

In minor amounts, for example up to 5% by weight, based on the total weight of component d2, component d2 can also contain urethione groups, for example for capping the isocyanate groups.

In the context of the present invention, an aliphatic diisocyanate d2 is primarily linear or branched alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, e.g. 1, 6-hexamethylene diisocyanate, isophorone diisocyanate or methylene bis (4-isocyanatocyclohexane) understood. Particularly preferred aliphatic diisocyanates d2 are 1,6-hexamethylene diisocyanate and isophorone diisocyanate.

Preferred isocyanurates include aliphatic isocyanurates derived from alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, e.g. Isophorone diisocyanate or methylene bis (4-isocyanatocyclohexane). The alkylene diisocyanates can be linear or branched. Isocyanurates based on n-hexamethylene diisocyanate, for example cyclic trimers, pentamers or higher oligomers of n-hexamethylene diisocyanate, are particularly preferred.

In general, component d2 is used in amounts of 0.01 to 5, preferably 0.05 to 4 mol%, particularly preferably 0.1 to 4 mol%, based on the sum of the molar amounts of A and B.

In general, all customary and commercially available divinyl ethers can be used as the divinyl ether d3. 1,4-butanediol divinyl ether, 1,6-hexanediol divinyl ether or 1,4-cyclohexanedimethanol divinyl ether or mixtures thereof are preferably used.

The divinyl ethers are preferably used in amounts of from 0.01 to 5, in particular from 0.2 to 4,% by weight, based on the total weight of A and B.

Examples of preferred partially aromatic polyesters are based on the following components

A, B, d1

A, B, d2 A, B, d1, d2

A, B, d3

A, B, d

A, B, d, d3

A, B, c3, c4 A, B, c3, c4, c5 A, B, d1, c3, c5 A, B, c3, d3 A, B, c3, d1 A, B, d, c3, d3 A, B, c2

Among them, partially aromatic polyesters based on A, B, d1 or A, B, d2 or on A, B, d1, d2 are particularly preferred. According to another preferred embodiment, the partially aromatic polyesters are based on A, B, c3, c4, c5 or A, B, d1, c3, c5.

The partially aromatic polyesters mentioned are generally biodegradable. The statement "biodegradable" means that the definition given in DIN V 54900 of biodegradability is met.

In general, biodegradability means that the polyesters disintegrate in a reasonable and detectable period of time. The breakdown can take place hydrolytically and / or oxidatively and can be mainly caused by the action of microorganisms such as bacteria, yeasts, fungi and algae. Biodegradability can be determined, for example, by mixing polyester with compost and storing it for a certain time. According to ASTM D 5338, ASTM D 6400 and DIN V 54900, CO ₂ -free air is allowed to flow through, for example, matured compost during composting and is subjected to a defined temperature program. The biodegradability is calculated as the ratio of the net CO ₂ release of the sample (after deduction of the CO ₂ release by Compost without sample) to the maximum CO ₂ release of the sample (calculated from the carbon content of the sample) biodegradability defined. Biodegradable polyesters usually show clear signs of degradation such as fungal growth, cracking and pitting after just a few days of composting.

The production of the partially aromatic polyesters is known per se or can be carried out according to methods known per se.

The preferred partially aromatic polyesters are characterized by a molecular weight (M _n ) in the range from 1000 to 100000, in particular in the range from 9000 to 75000 g / mol, preferably in the range from 10000 to 50,000 g / mol and a melting point in the range from 60 to 170 , preferably in the range from 80 to 150 ° C.

The aliphatic and / or partially aromatic polyesters mentioned can have hydroxyl and / or carboxyl end groups in any ratio. The aliphatic and / or partially aromatic polyesters mentioned can also be end group-modified be decorated. For example, OH end groups can be acid-modified by reaction with phthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid or pyromellitic anhydride.

Generally known as components ii) of the thermoplastic molding compositions are polyesters based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compounds.

A first group of preferred polyesters ii) are polyalkylene terephthalates, in particular with 2 to 10 carbon atoms in the alcohol part.

Such polyalkylene terephthalates are known per se and are described in the literature. They contain an aromatic ring in the main chain, which comes from the aromatic dicarboxylic acid. The aromatic ring can also be substituted, for example by halogen such as chlorine and bromine or by C 1 -C ₄ -alkyl groups such as methyl, ethyl, i- or n-propyl and n-, i- or t- butyl groups.

These polyalkylene terephthalates can be prepared in a manner known per se by reacting aromatic dicarboxylic acids, their esters or other ester-forming derivatives with aliphatic dihydroxy compounds.

Preferred dicarboxylic acids are 2,6-naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid or mixtures thereof. Up to 20 mol%, preferably not more than 10 mol%, of the aromatic dicarboxylic acids can be replaced by aliphatic or cycloaliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids and cyclohexanedicarboxylic acids.

Of the aliphatic dihydroxy compounds, diols having 2 to 6 carbon atoms, in particular 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-hexanediol, 1,4-cyclohexanediol, 1 , 4-cyclohexanedimethanol and neopentyl glycol or mixtures thereof are preferred.

Particularly preferred polyesters ii) are polyalkylene terephthalates which are derived from alkanediols having 2 to 6 carbon atoms. Of these, particularly preferred are polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate or mixtures thereof, in particular polybutylene terephthalate. Also preferred are PET and / or PBT, which can also contain up to 1% by weight of 1,6-hexanediol and / or 2-methyl-1,5-pentanediol as further monomer units. The viscosity number of the polyesters suitable as component ii) is generally in the range from 50 to 220 ml / g, preferably from 80 to 160 ml / g (measured in a 0.5% strength by weight solution in a phenol / o-dichlorobenzene mixture (Weight ratio 1: 1 at 25 ° C) according to EN ISO 1628-1.

Furthermore, as component ii) of the molding compositions according to the invention, PET recyclates (also called scrap PET) may be used, if appropriate in a mixture with polyalkylene terephthalates such as PBT.

Recyclates are generally understood to mean:

1) so-called post industrial recyclate: this is production waste from polycondensation or processing e.g. Sprues in injection molding processing, approach goods in injection molding processing or extrusion or edge sections of extruded sheets or foils.

2) Post consumer recyclate: these are plastic items that are collected and processed by the end consumer after use. The most dominant item in terms of quantity are blow-molded PET bottles for mineral water, soft drinks and juices.

Both types of recyclate can either be in the form of regrind or in the form of granules. In the latter case, the pipe cyclates are melted and granulated in an extruder after separation and cleaning. This usually facilitates handling, flowability and meterability for further processing steps.

Recyclates, both granulated and in the form of regrind, can be used, the maximum edge length being 6 mm, preferably less than 5 mm.

Due to the hydrolytic cleavage of polyesters during processing (due to traces of moisture), it is advisable to pre-dry the recyclate. The residual moisture content after drying is preferably <0.2%, in particular <0.05%.

Another group of the compounds suitable as component ii) are fully aromatic polyesters which are derived from aromatic dicarboxylic acids and aromatic dihydroxy compounds. Aromatic dicarboxylic acids which are suitable are the compounds already described for the polyalkylene terephthalates. Mixtures of 5 to 100 mol% isophthalic acid and 0 to 95 mol% terephthalic acid, in particular mixtures of approximately 80% terephthalic acid with 20% isophthalic acid to approximately equivalent mixtures of these two acids, are preferably used for fully aromatic polyesters.

The aromatic dihydroxy compounds preferably have the general formula (VI)

in which Z represents an alkylene or cycloalkylene group with up to 8 C atoms, an arylene group with up to 12 C atoms, a carbonyl group, a sulfonyl group, an oxygen or sulfur atom or a chemical bond, and in which m 'represents Has value 0 to 2. The compounds can also carry C ₁ -C ₆ alkyl or alkoxy groups and fluorine, chlorine or bromine as substituents on the phenylene groups.

Examples of these are the parent bodies of these compounds

dihydroxydiphenyl,

Di (hydroxyphenyl) alkane,

Di (hydroxyphenyl) cycloalkane,

Di (hydroxyphenyl) sulfide,

Di- (hydroxyphenyl) ether, di- (hydroxyphenyl) ketone, di- (hydroxyphenyl) sulfoxide, a, a'-di- (hydroxyphenyl) dialkylbenzene,

Di (hydroxyphenyl) sulfone, di (hydroxybenzoyl) benzene

Resorcinol and hydroquinone and their core alkylated or nuclear halogenated derivatives.

Of these will be

4,4'-dihydroxydiphenyl, 2,4-di- (4'-hydroxyphenyl) -2-methylbutane a, a'-di- (4-hydroxyphenyl) -p-diisopropylbenzene, 2,2-di- (3'- methyl- '-hydroxyphenyl) propane and 2,2-di- (3'-chloro - ^ '- hydroxyphenyl) propane;

as well as in particular

2,2-di- (4'-hydroxyphenyl) propane

2,2-di- (3 ', 5-dichlorodihydroxyphenyl) propane, 1,1-di- (4'-hydroxyphenyl) cyclohexane, 3,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylsulfone and 2,2-di ( 3 ', 5 ^, -dimethyl-4'-hydroxyphenyl) propane

or mixtures thereof are preferred.

It is of course also possible to use mixtures of polyalkylene terephthalates and fully aromatic polyesters as component ii). These generally contain 20 to 98% by weight of the polyalkylene terephthalate and 2 to 80% by weight of the fully aromatic polyester.

Of course, polyester block copolymers such as copolyether esters can also be used as component ii). Products of this type are known per se and are described in the literature, for example in US Pat. No. 3,651,014. Corresponding products are also commercially available, for example Hytrel ^® (DuPont).

According to the invention, polyester ii) should also be understood to mean polycarbonates. Suitable polycarbonates are, for example, those based on diphenols of the general formula (VII)

wherein Q is a single bond, a C, ~ to C ₈ alkylene, a C _∑ - to C ₃ alkylidene, a C ₃ - to C ₆ -cycloalkylidene group, a C ₆ - to C ₁₂ -arylene group and -O- , -S- or -SOz- means and n 'is an integer from 0 to 2.

The diphenols may also have substituents such as C ₆ to C alkyl or C1 to C6 alkoxy to the phenylene radicals.

Preferred diphenols of the formula VII are, for example, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,4-bis (4-hydroxyphenyl) 2-methylbutane, 1,1-bis (4-hydroxyphenyl) cyclohexane. 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) cyclohexane, and 1,1-bis (4-hydroxyphenyl) -3,3,5- are particularly preferred. trimethylcyclohexane.

Both homopolycarbonates and copolycarbonates are suitable as component ii); in addition to the bisphenol A homopolymer, the copolycarbonates of bisphenol A are preferred.

The suitable polycarbonates can be branched in a known manner, preferably by incorporating 0.05 to 2.0 mol%, based on the sum of the diphenols used, of at least trifunctional compounds, for example those having three or more than three phenolic compounds OH groups.

Polycarbonates have proven to be particularly suitable which have relative viscosities η _re ι of 1.10 to 1.50, in particular of 1.25 to 1.40. This corresponds to average molecular weights M _w (weight average) of 10,000 to 200,000, preferably from 20,000 to 80,000 g / mol.

The diphenols of the general formula VII are known per se or can be prepared by known processes.

The polycarbonates can be prepared, for example, by reacting the diphenols with phosgene by the interfacial process or with phosgene by the process in a homogeneous phase (the so-called pyridine process), the molecular weight to be set in each case being achieved in a known manner by a corresponding amount of known chain terminators. (With regard to polycarbonates containing polydiorganosiloxane, see, for example, DE-OS 33 34 782).

Suitable chain terminators are, for example, phenol, p-t-butylphenol but also long-chain alkylphenols such as 4- (1,3-tetramethylbutyl) phenol, according to

DE-OS 2842 005 or monoalkylphenols or dialkylphenols with a total of 8 to 20 carbon atoms in the alkyl substituents according to DE-A 35 06 472, such as p-nonylphenyl, 3,5-di-t-butylphenol, pt-octylphenol, p-dodecylphenol , 2- (3,5-dimethylheptyl) phenol and 4- (3,5-dimethylheptyl) phenol.

Amorphous polyester carbonates may be mentioned as further suitable components ii), with phosgene being replaced by aromatic dicarboxylic acid units such as isophthalic acid and / or terephthalic acid units during production. For further details, reference is made to EP-A 711 810. Further suitable copolycarbonates with cycloalkyl radicals as monomer units are described in EP-A 365916.

Bisphenol A can also be replaced by Bisphenol TMC. Such polycarbonates are available under the trademark APEC HT ^® from Bayer AG.

The thermoplastic molding compositions according to the invention usually contain from 0.1 to 50% by weight, preferably from 5 to 40% by weight, particularly preferably from 10 to 20% by weight of component i) and from 50 to 99.9% by weight. %, preferably from 60 to 95% by weight, particularly preferably from 80 to 90% by weight, of component ii), the percentages by weight in each case relating to the total weight of components i) to ii).

The thermoplastic molding compositions according to the invention can contain additives iii) which are incorporated during the polymerization process of components i) and / or ii) in any stage or subsequently, for example into a melt of the polyester, or during the mixing of components i) and ii) can. Stabilizers, neutralizing agents, lubricants and release agents, anti-blocking agents, dyes or fillers are mentioned as examples.

Based on the total weight of components i) and ii), from 0 to 80% by weight of additives can be added. Suitable additives are, for example, fillers, stabilizers or lubricants and mold release agents. Such additives are e.g. described in detail in Kunststoff-Handbuch, Vol. 3/1, Carl Hanser Verlag, Munich, 1992, pp. 24 to 28.

Examples of fillers are particulate substances such as calcium carbonate, clay minerals, calcium sulfate, barium sulfate, titanium dioxide, carbon black, lignin powder, iron oxide, which can also act as coloring constituents, and fiber materials, e.g. Cellulose fibers, sisal and hemp fibers. The proportion of fillers is generally not more than 40% by weight, based on the total weight of the molding composition according to the invention, in particular not more than 20% by weight.

Stabilizers are, for example, tocopherol (vitamin E), organic phosphorus compounds, mono-, di- and polyphenols, hydroquinones, diarylamines, thioethers, melamine or urea. Talc, chalk, mica or silicon oxides can be used as antiblocking agents. Lubricants and mold release agents are generally substances based on hydrocarbons, fatty alcohols, higher carboxylic acids, metal salts of higher carboxylic acids such as calcium or zinc stearate, fatty acid amides such as erucic acid amide and wax types, for example paraffin waxes, beeswax, montan waxes and the like. Preferred release agents are erucic acid amide and / or wax types and particularly preferred preferably combinations of these two types of release agents. Preferred wax types are beeswaxes and ester waxes, in particular glycerol monostearate. The molding compositions according to the invention are particularly preferably equipped with 0.05 to 2.0% by weight erucic acid amide or 0.1 to 2.0% by weight wax types, in each case based on the plastic content of the molding compositions.

The molding compositions according to the invention can be produced from the individual components by known processes. For example, the polyesters which can be used according to the invention as component i) can be introduced into component ii) by various methods. For example, the polyesters i) can be combined with one or more of the monomer components for the preparation of the polyesters ii), e.g. the dicarboxylic acids and / or diols can be admixed during the preparation of component ii). According to another procedure, the polyesters i) can be incorporated into the melt of the fully reacted polyesters ii).

Component i) can also be introduced into the polyester ii) previously prepared by known processes and with the aid of known mixing devices (see, for example, Saechtling, Kunststoff-Taschenbuch, Hanser Verlag, Munich, Vienna, edition 26, 1995, pages 191 to 246). Component i) can, for example with the help of a screw machine, e.g. of an extruder, either in pure form or as a so-called "masterbatch", are mixed in component ii).

In general, these masterbatches are special molding compositions in which the required additives or additives, for example also component i), are embedded in a matrix of, for example, thermoplastic polymer, for example component ii), but the additive content compared to usual additive molding compositions is significantly higher, for example in the range from 10 to 70% by weight. By adding appropriate amounts of a masterbatch to a non-additive thermoplastic, for example, molding compositions can then be produced with conventional additive contents.

Components i) and ii) can also be produced independently of one another and, for example, in granulate form either separately from one another or after prior mixing of the granules by known processes using known mixing and processing devices directly to give blends, moldings, foils, bristles, filaments, monofilaments or Fibers are processed. In this embodiment of the invention, the molding compositions according to the invention are only produced in the tool used, for example, for fiber production. The thermoplastic molding compositions according to the invention are particularly suitable for the production of blends, moldings, foils, bristles, filaments, monofilaments or fibers. The preparation can be carried out according to methods known to the person skilled in the art.

A particular field of application of the molding compositions according to the invention relates to the use for the production of bristles, in particular those bristles which are used for the production of brushes, paint brushes, cosmetic brushes, brooms, brushes and, particularly preferably, toothbrushes.

Another particular field of application of the molding compositions according to the invention relates to the use for the production of filaments, monofilaments or fibers, in particular those filaments, monofilaments or fibers which are used for the production of filters, ribbons, braids, twists or fabrics.

The diameter of the bristles, filaments, monofilaments or fibers that can be produced from the molding compositions according to the invention can generally be varied within a wide range and is, for example, in the range from 0.05 to 4.0 mm, preferably from 0.1 to 1.5 mm. The diameter of the toothbrush bristles that can be produced from the molding compositions according to the invention is generally in the range from 0.1 to 0.9 mm, preferably from 0.15 to 0.25 mm.

The length of the bristles, filaments, monofilaments or fibers that can be produced from the molding compositions according to the invention is not essential to the invention and can be varied within wide ranges.

With the aid of the thermoplastic molding compositions according to the invention, polymer compositions are made available from which blends, molded parts, foils, bristles, filaments, monofilaments or fibers can be produced, which have a bending stiffness that can be specifically set and is more independent of the water content than the blends, molded parts that can be produced from known molding compositions , Foils, bristles, filaments, monofilaments or fibers.

Examples:

Application measurements:

The molecular weight M _{n of} the polymers was determined as follows: 15 mg of the polymers were dissolved in 10 ml of hexafluoroisopropanol (HFIP). In each case 125 μl of this solution were analyzed by means of gel permeation chromatography (GPC). The measurements were carried out at room temperature. HFIP + 0.05% by weight trifluoroacetic acid Ka salt was used for the elution. The elution rate speed was 0.5 ml / min. The following column combination was used (all columns manufactured by Showa Denko Ltd., Japan): Shodex ^® HFIP-800P (diameter 8mm, length 5 cm), Shodex ^® HFIP-803 (diameter 8mm, length 30 cm), Shodex ^® HFIP-803 (diameter 8mm, length 30 cm). The polymers were detected using an Rl detector (differential refractometry). The calibration was carried out using narrowly distributed polymethyl methacrylate standards with molecular weights from M _n = 505 to M _n = 2,740,000. Elution ranges outside this interval were determined by extrapolation.

The melting temperatures of the polymers were determined by DSC measurements using an Exstet DSC 6200R from Seiko:

10 to 15 mg of the respective samples were heated from -70 ° C. to 200 ° C. under a nitrogen atmosphere at a heating rate of 20 ° C./min. The peak temperatures of the melting peak observed were given as the melting temperatures of the samples. An empty sample pan was used as a reference.

The bending stiffness of the monofilaments was determined as follows:

a) Pretreatment:

All measurements were carried out in a standard climate for the testing of textiles according to DIN 53802 at constant climate (20 ± 2) ° C and (65 ± 2)% relative humidity at 860 to 1060 mbar air pressure and max. 1 m / s air speed performed.

To determine the bending stiffness dry, the bristle samples were stored in this constant climate for 14 days before the measurement.

To determine the flexural rigidity, the bristle samples were stored in demineralized water at (20 ± 2) ^C C for 14 days before the measurement. Immediately before the measurement, the surface moisture was removed with a soft cloth.

b) Measuring the diameter of the bristles:

The diameter of the bristle samples was measured on 10 pieces using a thickness measuring device (measuring range 0-10 mm; measuring accuracy 0.001 mm). For this, the bristle pattern to be measured was placed under the stamp of the thickness measuring device and rotated on one side around the longitudinal axis. The lowest and the highest diameter values were read from the device display and noted. This procedure was repeated for each piece of bristle, so that 20 values (10 min. And 10 max.) held. The mean value was then calculated from these 20 values.

c) Measuring the bending force:

Using a Lorentzen & Wettre Elektronics bending stiffness tester, the stiffness of 10 test pieces each of the bristle patterns was determined in accordance with DIN 53121 (determination of the bending stiffness according to the beam method, testing of paper, cardboard and cardboard) or ISO 2493 (paper and board - determination of resistance to bending) measured in cN. For this purpose, 50 mm long bristle patterns were clamped in the jaws, the force measuring sensor was placed and adjusted at a distance of 1 mm from the clamp. The bristle was bent to an angle of 30 ° and back to 0 ° at constant speed and the maximum force F in cN was measured.

d) Calculation of the bending stiffness:

The bending stiffness in N / mm2 was calculated using the formula: B = F * L / D3, with B = bending stiffness F = bending force at a bending angle of 30 ° L = distance between clamp and force measuring sensor D = diameter of the bristle

Starting Materials:

Component i):

Pi-1: To prepare the polyester Pi-1, 87.3 kg of dimethyl terephthalate, 80.3 kg of adipic acid, 117 kg of 1,4-butanediol and 0.2 kg of glycerol were mixed together with 0.028 kg of tetrabutyl orthotitanate (TBOT), the molar ratio between alcohol components and acid component was 1.30. The reaction mixture was heated to a temperature of 180 ° C. and reacted at this temperature for 6 hours. The temperature was then raised to 240 ° C. and the excess dihydroxy compound was distilled off under vacuum over a period of 3 hours. 0.9 kg of hexamethylene diisocyanate were then slowly metered in at 240 ° C. over the course of 1 hour.

The polyester Pi-1 thus obtained had a melting temperature of 119 ° C. and a molecular weight (M _n ) of 23,000 g / mol.

Components ii): The following were used as component ii):

P-ii-1: Polybutylene terephthalate (PBT) Ultradur B4500 ^® from BASF Aktiengesellschaft with a density of 1.3 g / cm ³ (measured according to ISO 1183) and a viscosity number of 130 ml / g (VN measured in 0.05 wt. -% solution of phenol / o-dichlorobenzene, 1: 1 mixture, at 23 ° C according to ISO 307).

Other components:

The following were used as components for the production of molding compositions not according to the invention:

P-V-1: A polyamide made from hexamethylene diamine and dodecanedioic acid (PA 6.12).

Production of the molding compositions according to the invention:

To produce the molding compositions according to the invention, the starting materials listed in Table 1 were mixed in granular form in a tumble mixer at room temperature for 10 minutes, and further processed into monofilaments as described below.

Table 1 :

Monofilherstellung:

From the molding compositions F-1, F-V1 and F-V2, a melt was produced at 240 to 260 ° C in a 45 mm extruder with a length / diameter ratio of 26, at 260 ° C with a 20cm3 gear pump dispensed through a 40-hole nozzle (hole diameter 0.7 mm) and cooled by a water bath at 55 ° C for F-1 and F-V1, or 20 ° C for F-V2. The drawing of the 40 filaments was first carried out in hot air at 180 ° C. to a factor of 3.1 and then in hot air at 210 ° C. to a factor of 4.7 in total. The filaments were subsequently relaxed at 210 ° C. shrunk back so that after relaxation there was a stretching by a factor of 4.3.

The filaments were wound on reels, bundled in strands and cut into 1.5 m long bristle bundles.

The monofilaments had the bending stiffness shown in Table 2.

Table 2:

*: Comparative experiment, not according to the invention

Compared to the molding compounds F-V1 and F-V2, monofilaments with a comparatively low bending stiffness that is independent of the water content could be produced from the molding compound F-1.

Claims

claims

1. Thermoplastic molding composition containing

2. Thermoplastic molding composition according to claim 1, wherein the polyester i) is composed of:

A) an acid component

a3) 0 to 5 mol% of a compound containing sulfonate groups,

where the molar percentages of components a1) to a3) together give 100% and

B) a diol component from at least one C _{2 to} C ₁₂ alkanediol or a C ₅ to C ₁₀ cycloalkanediol or mixtures thereof

and, if desired, one or more components selected from a component selected from

d) at least one dihydroxy compound of the formula I containing ether functions

HO - [(CH ₂ ) _n -Oj _m -H (I) in which n is 2, 3 or 4 and m is an integer from 2 to 250,

c2) at least one hydroxycarboxylic acid of the formula IIa or IIb

(IIb) in which p is an integer from 1 to 1500 and r is an integer from 1 to 4, and G represents a radical which is selected from the group consisting of phenylene, - (CH ₂ ) _q -, where q a whole

Number from 1 to 5 means -C (R) H- and -C (R) HCH ₂ , where R is methyl or ethyl

c3) at least one amino-C ₂ to C ₁₂ -alkanol or at least one amino-C _{5 to} C ₁₀ -cycloalkanol or mixtures thereof

c4) at least one diamino-Cr to C ₈ alkane

c5) at least one 2,2'-bisoxazoline of the general formula III

wherein R ^{1 is} a single bond, a (CH ₂ ) ₂ alkylene group, with z = 2, 3 or 4, or a phenylene group

( ^{| Va} ) (IVb) in which s is an integer from 1 to 1500 and t is an integer from 1 to 4, and T is a radical which is selected from the group consisting of phenylene, - (CH ₂ ) _U -, where u is an integer from 1 to 12, -C (R ² ) H- and -C (R ² ) HCH ₂ , where R ^{2 is} methyl or ethyl,

and polyoxazolines with the repeating unit V

in which R ^{3 represents} hydrogen, d-Ce-alkyl, C ₅ -C ₈ cycloalkyl, unsubstituted or with C 1 -C ₄ -alkyl groups up to triply substituted phenyl or tetrahydrofuryl,

or mixtures of d) to c6)

and

D) a component selected from

d2) at least one isocyanate

d3) at least one divinyl ether

or mixtures of d1) to d3).

3. Thermoplastic molding composition according to claims 1 to 2, wherein component ii) is at least one polyalkylene terephthalate.

4. Thermoplastic molding composition according to claims 1 to 3, wherein component ii) is polybutylene terephthalate.

5. A process for the production of molding compositions according to claims 1 to 4, characterized in that components i) to iii) are mixed.

6. Use of the molding compositions according to claims 1 to 4 for the production of blends, moldings, foils, bristles, filaments, monofilaments or fibers.

7. blends, moldings, foils, bristles, filaments, monofilaments or fibers, obtainable from the molding compositions according to claims 1 to 4.

8. Brushes, color brushes, cosmetic brushes, brooms, brushes or toothbrushes, including bristles, obtainable from the molding compositions according to claims 1 to 4.

9. Filters, ribbons, braids, threads or fabrics, comprising filaments, monofilaments or fibers, obtainable from the molding compositions according to claims 1 to 4.

10. Use of aliphatic polyesters or polyesters based on aliphatic and aromatic dicarboxylic acids and aliphatic dihydroxy compounds to improve the bending stiffness of polyesters based on aromatic dicarboxylic acids and aliphatic or aromatic dihydroxy compounds.