DE3031491A1 - Aromatic polyester with improved melt flow - comprises polyester prepd. from isophthalic and (or) terephthalic acid and aromatic di:hydroxy cpd. and pentaerythritol tetra:stearate - Google Patents

Abstract

An aromatic polyester compsn. with improved flow properties comprises 97-99.99 wt.% thermoplastic polyester (I) prepd. from aromatic dihydroxy cpds., isophthalic- and/or terephthalic acid, chain terminating agents and opt. branching agents and 0.01-3 wt. % pentaerythritol tetrastearate (II) as flow agent. Up to 45 mol.% of the ester gps. in (I) can be substd. by carbonate gps. (II) improves the melt flow of (I) without effecting transparency and colour of (I) and with substantially less deterioration of strength and heat deformation resistance of (I). The compsn. is used for mouldings e.g. injection mouldings on semi-finished extruded articles.

Description

Aromatic polyesters with improved flowability

The invention relates to thermoplastic aromatic polyesters which to improve the flowability in the melt pentaerythritol tetrastearate contain.

Aromatic polyesters are known (W.M. Eareckson, J. Polym. Sci. XL, 399-406 (1959); Andre Conix, "Thermoplastic Polyesters from Bisphenols," Ind. Eng Chem., Vol. 51, No. 2, 147-150, Feb. 1959; FR 1 177 517, US 3 351 624, DE-AS 1 445 385). They are everywhere because of their excellent properties used where high heat resistance and toughness are required.

Although the aromatic polyesters meet most of the requirements, which the professional world puts on them, one is interested in the fluidity of the Melt still to improve. Various measures have already been proposed for this purpose been: On the one hand, there is the problem of alloying with ABS resins (JP-OS 73/25 053), polyethylene tere- phthalate (DE-OS 23 33 017, JP-OS 74/23 844, US 39 46 091) polyethylene hydroxibenzoate (JP-OS 75/5443, US 38 84 990), polytetrafluoroethylene (JP-OS 75/5444), copolyesters of ethylene glycol, terephthalic and p-hydroxybenzoic acid (JP-OS 75/64 351), aliphatic or aromatic polyesters (JP-OS 75/96 652) and polyamides (DE-OS 26 46 728) tried to solve, but then not only the heat resistance and the mechanical properties of the obtained Alloys left some wishes unfulfilled, but transparency was also lost.

On the other hand, it has also been suggested that the flowability be more aromatic To increase polyester by adding the following low molecular weight auxiliaries: trialkyl phosphates (JP-OS 74/34 546), diphenyl sulfoxide (JP-OS 74/86 433), esters of aromatic phosphonic acids (JP-OS 76/37 145) and esters of aromatic carboxylic acids (JP-OS 76/37 146). Because of the High vapor pressure of these compounds must be considered in view of the high processing temperatures aromatic polyester with evaporation losses and even with self-ignition Calculate flow aids.

According to JP-OS 74/129 747, esters or partial esters are more saturated aliphatic C12-C30 monocarboxylic acids and saturated aliphatic <C30 monocarboxylic acids or polyalcohols, e.g. ethylene glycol melissinate, as mold release agents for aromatic Polyester used. We have now found that these mold release agents also Increase fluidity, that, surprisingly, pentaerythritol tetrastearate the toughness and heat resistance of aromatic polyesters are significantly less impaired than other esters.

The invention relates to mixtures containing A) 97 to 99.99, preferably 98 to 99.9% by weight, based on the sum of A and B, more thermoplastic Polyesters made from aromatic dihydroxy compounds and iso- and / or terephthalic acid, Chain terminators and optionally branching agents, with up to 45 mol% of the Ester groups can be replaced by carbonate groups, and B) 0.01 to 3, preferably 0.1 to 2.% by weight, based on the sum of A and B, flow aid, thereby characterized in that the flow aid is pentaerythritol tetrastearate.

Another object of the invention is the production of thermoplastic aromatic polyesters, characterized in that A and B are known per se Way mixes with each other.

The invention also relates to the use of these mixtures for the production of moldings.

The aromatic polyesters A generally have relative solution viscosities from 1.18 to 2.0, preferably from 1.2 to 1.5 (measured with a solution of 0.5 g substance in 100 ml CH2Cl2 solution at 250C).

Preferred diphenols for the production of the aromatic polyesters are compounds of the formula HO - Z - OH (I) in which Z is a divalent mono- or Polynuclear aromatic radical with 6-30 C atoms means, where Z is built in this way is that the two OH groups are directly attached to a carbon atom of an aromatic system are bound.

Particularly preferred diphenols are compounds of the formula in which Y is a single bond, an alkylene or alkylidene radical with 1 - 7 carbon atoms, a cycloalkylene or cycloalkylidene radical with 5 - 12 carbon atoms, -O-, -S-, means, as well as their nucleus alkylated and nucleus halogenated derivatives, eg

Hydroquinone, resorcinol, Dihydroxidiphenyls, bis (hydroxiphenyl) -alkane bis (hydroxiphenyl) cycloalkanes, bis (hydroxiphenyl) sulfides, bis (hydroxiphenyl) ethers, Bis (hydroxiphenyl) ketones, bis (hydroxiphenyl) sulfoxides, bis (hydroxiphenyl) sulfones and α, α'-bis (hydroxiphenyl) -diisopropylbenzenes and their nucleus alkylated and nuclear halogenated compounds, in particular e.g. bisphenol A = 2,2-bis (4-hydroxyphenyl) propane, Tetramethylbisphenol A, 1,1-bis- (4-hydroxiphenyl) -isobutane, 1,1-bis- (4-hydroxiphenyl) -cyclohexane, 4,4'-dihydroxidiphenyl sulfide, 4, O'-dihydroxidiphenyl, 4,4'-dihydroxidiphenyl sulfone and their di- and tetrahalogenated derivatives. Bisphenol is particularly preferred A. Any mixtures of the aforementioned diphenols can also be used.

As a chain terminator for aromatic polyesters, their flowability can be improved according to the invention are preferably phenol, alkylphenols with Cl C12-alkyl groups, halogenated phenols, hydroxidiphenyl, naphthols, carbonic acid esters from such phenolic compounds and chlorides of aromatic monocarboxylic acids, which may be substituted by C1-C22-alkyl groups and halogen atoms can, in amounts of 0.1 to 10 mol% (in the case of phenols based on diphenols, in the case of acid chlorides based on acid dichlorides).

As a branching agent for aromatic polyesters, their flowability can be improved according to the invention, preferably three or more functional Carboxylic acid chlorides or 3- and higher-valent phenols in amounts of 0.01 to 1 mol%, based on the dicarboxylic acid chlorides used or the diphenols used In addition, the aromatic polyesters can contain up to 10 mol of acid anhydride groups (based on the sum of carbon ester, carbonate and anhydride groups).

Processes for the production of aromatic polyesters are known: You can from diphenols of is- and / or terephthalic acid, chain terminators and optionally Branching agents after the transesterification process or from diphenols, iso- and / or Terephthalic acid dichlorides, chain terminators and optionally branching agents produced in the melt, in solution or by the interfacial process will; see V.V. Korshak and S.V. Vinogradova, "Polyesters", Pergamon Press, 1965.

The partial replacement of the ester groups by carbonate groups is also known (G.S. Kolesnikow et. Al., J. Polym. Sci.

USSR, Vol. 9, 1967, pp. 1705-1711; U.S. 2,030,331; 3,169,121r 3,409 704, DE-OS 2 714 544, 2 758 030).

The incorporation of the powder to be used according to the invention present flow aid in the aromatic polyester takes place e.g. by Rolling onto the polyester granulate, subsequent homogenization in the extruder and re-granulation.

The flow aid can also be added to the polyesters during production, for example, before the evaporation of their solutions1 are added.

Finally, there is also the rolling up of the powdery flow aid on granules and their immediate processing .to moldings possible.

The addition of the flow aid to be used according to the invention makes noticeable in terms of transparency or color.

The aromatic treated according to the invention with flow aids Polyesters can be stabilizers, mold release agents, plasticizers and fillers, such as. Glass fibers, glass spheres, asbestos and carbon fibers, kieselguhr, kaolin, Contains rock flour and pigments.

They can be molded into molded articles by conventional methods in injection molding machines or processed into semi-finished products in extruders.

Examples In the following examples, the following is more aromatic Polyester used: Polyester A (iso- / terephthalic acid 1: 1 and bisphenol-A) 9.12 kg bisphenol-A, 4.14 kg iso- and 4.14 kg terephthalic acid dichloride and 0.15 kg phenol relative viscosity ml rel = 1.258 (Ubbelohde viscometer, solution of 0.5 g substance in 100 ml dichloromethane solution measured at 25 ° C) notched impact strength ak = 20.2 kJ / m2 (DIN 53 453) heat resistance Vicat B = 190 ° C (DIN 53 460, Method B) Melt index (MFI) = 36 g / 10 min. (DIN 53 735) residual chlorobenzene content = approx. 50 ppm In the aromatic polyester A were in a twin-screw extruder (Screw diameter 32 mm) at approx.

31000 incorporated the esters given in Table 1 and from the Mixtures of standard test specimens produced by the injection molding process.

Table 1: Esters used as flow aids a) pentaerythritol tetrastearate, Melting point 76 "C b) Triglyceride of palmitic, stearic and myristic acid in a molar ratio of 1: 1: 0.1, melting point 48au.

The proportions and the properties determined on the basis of the test specimens of the molding compounds are compiled in Table 2.

The melt index (MFI) was used to assess the flowability.

Table 2: Composition and properties of the molding compounds by-esters made of MFI #rel ak heat resistance Table 1 [g / 10 digkeit Vicat B [KJ / m²] [% by weight] min.] [° C] 1 a 0.2 82 1.251 16.2 185 2 a 0.1 57 1.254 17.8 187 3 a 0.5 132 1.248 14.7 182 Cu03 co> H-5 b 0.5 135 1.245 10.7 178 H h; o on nv it N sr S oD n N tn oo QQ I v tnJ Comparative examples

Claims (4)

Claims mixtures containing A) 97 to 9 ', 99% by weight, based on to the sum of A and B, thermoplastic polyester made from aromatic dihydroxy compounds and iso- and / or terephthalic acid, chain terminators and optionally branching agents, where up to 45 mol% of the ester groups can be replaced by carbonate groups, and B) 0.01 to 3% by weight, based on the sum of A and B, flow aid thereby geken, draws that the flow aid is pentaerythritol tetrastearate. 2. Mixtures according to claim 1, characterized in that they are 98 up to 99.9% by weight A and 0.1 to 2% by weight -90 B contain. 3. Process for the preparation of the mixtures according to claims 1-2, characterized in that A and B are mixed with one another in a manner known per se. 4. Use of the mixtures according to claims 1-2 for the production of molded bodies.