DE2509726A1 - POLYESTER MOLDING COMPOUNDS - Google Patents

Description

BASF Aktier * gese31soh.Hft

Our sign; O.Z 3r ^ Mr Kff / τΐΕ

6700 Ludwigshafen, 5 «3« 1975 Polyester molding compounds

The present invention "relates to thermoplastics Polyester molding compounds that stabilize against degradation through heat are.

High molecular weight thermoplastic polyesters such as Polyethylene terephthalate and polybutylene terephthalate are used as IiIm and fiber formers and for the production of molded parts Use. Polybutylene terephthalate in particular is used for the production of molded parts. Because of the excellent Crystallization ability of poly (1,4-butylene terephthalate) become at low mold temperatures and very Short processing cycles Molded parts with excellent toughness obtain.

Polyalkylene terephthalates and especially poly (1,4-butylene terephthalate) however, have the disadvantage that they during processing, e.g. during extrusion, during mixing with Additives and suffer degradation during injection molding. This leads to a lowering of the melt viscosity and a deterioration the physical and mechanical properties. In particular, the impact strength of the molded parts produced in this way is greatly degraded. The stabilizers commonly used for polyester resin compositions, such as sterically hindered phenols, Although aromatic amines and phosphorus compounds improve the long-term oxidation stability of the masses, they have no effect on the stability of the melt during processing.

It has now been found, surprisingly, that said Disadvantages can be avoided by the molding compositions according to the invention.

The invention relates to molding compositions which consist of

ORIGINAL INSPECTED _ ₂ _

809839/0982

- 2 - O.Zo 31 204

2509728

a) a linear thermoplastic polyester and

b) a copolyester from aromatic dicarboxylic acids,

1 to 100 mol $ butene-2-diol-1,4 and 0 to 99 mol $ of an aliphatic diol, this copolyester being produced from the components by polycondensation at temperatures below 230 ^° C., and optionally

c) customary additives such as fillers, pigments and like that.

Particularly suitable as component a) of the molding compositions according to the invention are polyesters made from aromatic dicarboxylic acids and aliphatic and cycloaliphatic diols. These polyesters can also contain small proportions of aliphatic dicarboxylic acids and other groups such as ethers or amides. Mixtures of different dicarboxylic acids and different diols in the polyesters can also be used as component a). The relative viscosity of the polyester is advantageously 1.5-1.7, measured in a 0.5% solution of the polyester in a mixture of phenol / o-dichlorobenzene 3: 2 at 25 ^° C. According to the invention, polyesters are particularly suitable consisting essentially of polybutylene terephthalate.

As component b) are, as already mentioned, copolyesters of aromatic dicarboxylic acids 1-100 Mo1- $ butene-2-diol-1,4, and 0 - 99 1 ° used an aliphatic diol. The preparation of these copolyesters can be prepared by per se conventional procedure, except that the condensation temperatures not exceed 230 ⁰ C. For example, a copolyester from terephthalic acid, 1,4-butanediol and 1,4-butene-2-diol is produced as follows:

In Reaktionaanaatz are dimethyl terephthalate, 1,4-butanediol and 2-butene-1,4-diol and heated for a common transesterification catalyst such as tetrabutyl to about 130 to 140 ⁰ C. The diols can be used in a 1.2 to 2 molar excess. The transesterification reaction begins at temperatures of about 130 ^° C. to 140 ^{° C.}

609839/0982 ~ ³ ~

O.Z. 31 204

2509728

tion. Over the course of 2.5 hours, the temperature is increased to about 190 ^° C., the theoretical amount of methanol being distilled off. The pressure is then continuously reduced to about 0.1 to 0.3 Torr over the course of 1.5 hours, and the temperature is reduced to increased to a maximum of 220 ^° C. At this temperature, the reaction is continued until the desired viscosity of the melt is reached.

It is essential in the production of the copolyesters based on butene-2-diol-1,4-1,4-diol used according to the invention that a temperature of 230 ^° C. is not exceeded during the polycondensation. This means that the polycondensation ^{temperature is less than 230 °} C. and slightly higher temperatures occur at most, for example on the wall of the apparatus, in heat exchangers, pipelines or filters.

The relative solution viscosity of those used in the present invention Copolyester should be 1.3 to 1.8. Copolyesters with relative solution viscosities between 1.5 and 1.7 are advantageous used. For stabilizing poly (1,4-butylene terephthalate) molding compounds Copolyesters with contents of 20 mol- $ to 99 mol- $ butene-2-diol-1,4 and the homopolymeric poly (1,4-butene-2-terephthalate) are preferably suitable. They can be used in amounts of 1 to 30 percent by weight, based on the amount of poly (1,4-butylene terephthalate), be present in the poly (1,4-butylene terephthalate) molding compound.

The molding compositions according to the invention are generally produced by mixing the granulated polyesters and the granulated butene-2-diol-1,4-containing copolyesters immediately before the last processing step, for example before injection molding or extrusion. However, the components can also be mixed in a separate operation, for example on a mixing extruder, and then granulated. When the components are mixed separately, temperatures of 230 ^° C. should only be used for a short time, preferably for less than 5 minutes. In the case of polyester molding compounds with melting temperatures below 230 ° C., the polymeric components can also be mixed in the melt, for example in a polycondensation autoclave, immediately following the polycondensation of the polyesters.

R 0 9 8 3 9/0 PR? ~ ⁴ ~

- 4 - O ₀ line 31 204

250972S

It should be particularly noted that the polyester molding compositions ₉ additives color pigments fillers ₅ flame retardants and the like may contain according to the invention as ₅ RuS ₅ plasticizers, fluidity improvers ;, stabilizers ^ Ultraviolettabsorptionsmittelj dyes ",,

The molding compositions according to the invention preferably contain reinforcing agents effective fillers. The proportion of filler can be 1 to about 80 parts by weight, based on 100 parts by weight of the polyester resin component and the filler. In general, any reinforcing agent can be used, such as fibers, whiskers, glass spheres, ceramic materials such as glass fibers, talc, chalk, titanate hair crystals, Quartz and the like. The preferred reinforcing fillers essentially include soda-free glass fibers and glass balls.

The particular advantage of the polyester molding compositions according to the invention is that they can be processed at higher temperatures and finished parts with excellent Properties, especially with high toughness and strength.

The particular advantage of the polyester molding compositions according to the invention is shown very clearly in the case of complex or thin-walled ones Prefabricated parts with long flow paths, for the production of which increased processing temperatures are absolutely necessary are.

In particular, the filler-containing polyester molding compounds According to the invention, the conventional filled polyester compositions are clearly superior, since these due to the occurring Shear forces and the required processing temperatures show a particularly strong reduction during processing and sometimes only achieve unsatisfactory finished part properties. The molding compositions according to the invention lead even at elevated processing temperatures to produce finished parts with excellent properties.

609839/0982

- 5 - O.Z. 51 204

Examples

TJnverstärktes poly (I ^ - "butylene terephthalate) having a relative viscosity of 1.66 dl / g was mixed with the stated in the following table copolyesters in the form of granules were prepared by an injection molding machine at melt tempera doors of 240, from the mixtures 260 and 280 ⁰ C. and an ambient temperature of 60 C. Rods with the dimensions 4 × 6 50 mm were produced to test the processing stability in all tests, the relative solution viscosity was measured after processing.

Since the impact strength is very sensitive to a reduction of the molecular weight was the hole notched impact strength of the moldings at 23 ⁰ C measured in accordance with DIN 53 453rd Since the test specimens with a standard notch in the impact strength test with a pendulum impact device in the test according to DIN 53 453 do not show any great differentiation in the measured values, the test was modified in such a way that a hole with a 3 mm diameter was drilled and a double notch was obtained. The notch impact strength a, ^. measured in kilojoules / m. It is struck in the longitudinal direction of the hole; the notch effect occurs on both sides. This test allows a very precise differentiation in the values of the impact strength of the test specimens.

The values given in the following were the relative solution viscosity of 0.5 #igen Löswqgai the polyester in a mixture of phenol / o-dichlorobenzene having the mixing ratio of 3: 2 obtained at 25 ⁰ G.

-6- 609839/0982

Copolyester

composition
in mol- #

Weight ant. Mass temp.
in the o ~

% _rel mixture OZ 31 204

250972S

Molded body ³ LK

30 butene-2-diol-1.4 1.53 10 70 butanediol 1.4
100 terephthalic acid

40 butene-2-diol-1,4 1.58 5 60 butanediol 1,4
100 terephthalic acid

40 butene-2-diol-1,4 1.58 10 60 butanediol 1,4
100 terephthalic acid

50 butene-2-diol-1,4 1.62 5 50 butanediol 1,4
-100 terephthalic acid

50 butene-2-diol-1,4 1.62 10 50 butanediol 1,4 100 terephthalic acid

70 butene-2-diol-1.4 1.56 20 30 butanediol 1.4 100 terephthalic acid

240
260
280 1,585
1.575
1.515 44
46
34 240
260
280 1.623
1.63
1.61 52
55
48 240
260
280 1.65
1.65
1.64 55
54
50 240
260
280 1.663
1.68
1.63 56
58
52 240
260
280 1.615
1.635
1.625 50
54
51 240
260
280 1.672
1.680
1, 61 61
63
50 240
260
280 1.643
1.652
1.61 52
56
48

609839/0982 -7-

Claims (6)

- 7 - 0.Z0 31? S 0 9 7? S claims 1. Thermoplastic molding compound, consisting of - a) a linear thermoplastic polyester b) a copolyester of aromatic dicarboxylic acids, 1 to 100 Kol-fo butenediol-1,4, and 0 to 99 mole # of an aliphatic diol, said copolyester is prepared from the components by polycondensation at temperatures below 230 ⁰ C. 2. Molding composition according to claim 1, characterized in that the copolyester is contained in amounts of 1 to 30 parts by weight, based on 100 parts of the molding composition. 3. Molding composition according to claim 1 and 2, characterized in that the linear thermoplastic polyester a) is a thermoplastic polyester composed of aromatic dicarboxylic acids or mixtures thereof and aliphatic or cycloaliphatic diols or diol mixtures. 4. Molding composition according to claims 1 to 3, characterized in that the copolyester b) consists of terephthalic acid, 1,4-butanediol and 1,4-butene-2-diol. 5. Molding composition according to claims 1 to 4, characterized in that it consists of poly (1,4-butylene terephthalate) and a copolyester of 1,4-butene-2-diol. 6. Molding composition according to claims 1 to 5, characterized in that it additionally contains reinforcing fillers. BASF Aktiengesellschaft 609839/0982 _ _n ORIGINAL INSPECTED