DE2363512A1 - MODIFIED ELASTOMER SEGMENTED MIXED POLYESTERS - Google Patents

Description

Pv / GW 509 Leverkusen. Bayerwerk

Dec. 19, 1973

Modified elastomeric segmented mixed polyesters

The present application relates to blends of elastomers segmented mixed polyesters and linear thermoplastic polyesters.

Thermoplastically processable elastomers of various degrees of hardness based on segmented mixed polyesters are known from numerous publications (DOS 2 035 333, 2 210 119,

2,213,128,240,801,2263,046, U.S. Patents 2,720,502, 3,023,192,

3,651,014; G.K. Hoeschele, W.K. Witsiepe, Angew. Macromolecule. Chemie, 267 (1973)) · According to these publications, dialkyl terephthalate with lower and higher molecular weight is used Glycols in varying proportions. Alkanediols are used as low molecular weight glycols, as higher molecular weight Glycols Polyalkylene oxide glycols with a molecular weight of about 1000-2000 are used. In this reaction, higher molecular weight arises Polyalkylene terephthalate high molecular weight plastics, which consist of different segments. The so-called hard segments are the high-melting crystalline polyterephthalate units formed by transesterification of the dialkyl terephthalate with the low molecular weight glycols, the so-called. Soft segments the low-melting polyalkylene oxide units; both segments are linked to form a block copolymer. Such Mixed polyesters are characterized by excellent mechanical properties, such as high tear resistance, good

Le A 15 436 - 1

509827/0742

Flexural strength, high specific resistance.

Both segments are responsible for the properties of these plastics determining: the proportion of highly crystalline rigid hard segments causes the hardness, the proportion of the low-melting soft segments the elasticity. By varying the proportions of hard and Soft segments can accordingly be adjusted to the desired hardness and elasticity of the products.

The disadvantage of this method of regulating hardness and elasticity is obvious: even minor changes in properties require the disproportionate effort of a modified polycondensation, so that with the variety of through the Modifications due to various uses due to the amount of mixed polyesters to be produced becomes unprofitable.

The object of the invention was therefore to segment the elastomeric ones To modify mixed polyesters to new substances that meet the various requirements in terms of hardness and Elasticity without meeting the disadvantages mentioned above.

Surprisingly, it has now been found that when blending elastomeric segmented mixed polyesters A with thermoplastic linear polyester B molding compounds can be produced, which have a significantly higher tensile strength - characterized by flexural or tensile modulus - without the elongation at break decreasing to the same extent. the modified segmented mixed polyesters according to the invention combine one in unexpectedly fortunate combination high impact resistance, even at low temperatures, with the known good properties of thermoplastic polyesters, e.g. good heat resistance, good solvent resistance, low water absorption. The disadvantages of the usual elastomer-thermoplastic blends such as splicing,

Le A 15 436 - 2 -

509827/0742

Segregation, poor breaking behavior, are completely avoided.

The present application therefore relates to thermoplastics Molding compositions, the 5-99 wt .-% of an elastomer segmented Mixed polyester A and 95-1% by weight of a linear thermoplastic Contain polyester B, characterized in that one component of the mixed polyester A and the Polyester B from the same ester units. exist and that the other component of the mixed polyester A in the copolymer is largely amorphous and has a glass transition temperature of <0 ° C.

As elastomeric segmented copolyester A commercially available products are suitable according to the above on page 1 literature with 40 - 70 wt -.% Hard segment content and 60 - 30 wt .-% of soft segment ratio, the molecular weight of these copolyesters is generally 15000 -'70000, preferably 20 000-40,000, the block length - expressed as molecular weight - 800-3000, preferably 950-2000.

The elastomeric copolyesters A used according to the invention advantageously contain, as soft segments, polyethers whose alkylene groups consist of 3 to 6, preferably 4 or 5, methylene groups. The ether bonds can be replaced by ester bonds up to 100%. Polyalkylene terephthalate sequences which are chemically largely identical to the added component B are suitable as hard segments of the mixed polyester. Due to the limited block length and the interaction with the soft segments, the melting point (- conveniently measured by differential thermal analysis -) can be reduced in comparison to pure polyalkylene terephthalate to 20 to 8O ⁰ C.

As thermoplastic polyesters B are polyalkylene terephthalates with an intrinsic viscosity of 20 to 180 ml / g, preferably of 60 to 130 ml / g, measured at 25 ° C according to the method given in Example 1

Le A 15 436 - 3 -

5 0 9827/0742

given method, suitable whose terephthalic acid residues up to 10 mol% due to phthalic acid, isophthalic acid, hexahydrophthalic acid residues or can be replaced by aliphatic dicarboxylic acid radicals having 3 to 6 carbon atoms. A further one Replacement of the terephthalic acid residues is not recommended because of the softening point of the elastomeric segmented mixed polyester A would be inexpediently greatly reduced as a result. The glycol components of the polyalkylene terephthalates contain 2 to 6, preferably 2 to 4, methylene groups.

Molding compositions with an elastomeric character, but with a significantly increased tensile strength compared to the pure component A one in the range above 40 wt .-%, preferably between 60 and 95 wt .-%, of component A. Compared with the pure Component A, by adding component B, a substantial increase in the modulus of elasticity and a - comparatively small - decrease in elongation at break. In the area mentioned there is even a composition with a maximum Tear resistance.

Thermoplastic products with only slightly reduced tensile strength compared to the pure component B, with high impact strength even at temperatures below 0 ° C. and with good heat resistance are obtained in the range of 5-40% by weight, preferably 10-30% by weight, of the component A. Compared with the known -Good properties of pure linear thermoplastic polyester B, the admixture brings the component a to increase the impact and notched impact strength, - percentage terms ¹ - is far greater than the drop in the elastic modulus and heat resistance.

The present invention enables by mere mixing of components A and B a continuous transition from elastomer to thermoplastic properties and thus opens up the new possibility 'by varying tensile strength as required,

Le A 15 436 - 4 -

509827/0742 - * ■■■■ ':

Heat resistance and hardness on the one hand and impact or Notched impact strength, elasticity and tear strength on the other hand the products can be easily adapted to the respective purpose and molded parts and foils that can withstand high thermal loads with very good impact resistance. - "

The mixtures according to the invention are preferably reinforced with the usual inorganic or organic fillers. In general, the reinforcing filler accounts for 5-60% by weight, preferably 20-50% by weight of the reinforced filler Mass - in particular - as fillers, glass fibers, micro glass beads, Asbestos or carbon fibers, potassium hexatitanate fibers, calcium silicate fibers, kieselguhr, kaolin, clays, Calcium carbonates aluminum oxide, polyester fibers or a Combination of these substances use.

If flame-retardant products are required, 2 to 20% by weight, based on the molding compound, flame retardants known per se, such as tetrabromophthalic anhydride, hexabromocyclododecane, Tetrachloro- and tetrabromobisphenol A, tris (nonylphenyl) phosphite, bis-polyoxyethylene hydroxymethylphosphonate, tris (2,3-dichloropropyl) phosphate, be added alone or in combination with antimony trioxide.

Processing aids such as nucleating agents can also be used and mold release aids, can be used in an effective amount. as Additions of 0.1-1% by weight proved to be particularly suitable Talc as a nucleating agent and / or 0.1-3% by weight of a sodium montanate as a mold release aid.

Furthermore, the novel molding materials may contain up to 3 w G _e .-% stabilizers and anti-aging agents. Suitable as such are phenols and phenol derivatives, preferably sterically hindered phenols which contain alkyl substituents with 1-6 carbon atoms in both o-positions to the phenolic hydroxyl group, and amines, preferably secondary arylamines, and their derivatives. Specific examples are 4,4'-bis- (2,6-di-tert-butyl-

Le A 15 436 - 5 - ■

50 9827/0742

phenol), 1,3,5-trimethyl-2,4,6-tr.is- (3,5-di-tert-butyl-butyl-4-hydroxy-benzyl) benzene, 4,4 '- -Butylidene-bis- (6-tert-butyl-mcresol), 3,5-di-tert-butyl-4-hydroxy-benzyl-phosphonic acid diethyl ester, N, N'-bis (ß-naphthyl) -p- phenylenediamine, N, N ¹ -bis- (1-methylheptyl) -p-phenylenediamine, phenyl-ß-naphthylamine.

4,4'-bis (#, cK-dimethylbenzyl) -diphenylamine is particularly preferred or 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy-hydrocinnamoyl) hexahydro-s-triazine is used.

To achieve color effects, colorants, such as carbon black, titanium dioxide, cadmium or iron pigments, can be added to the mixtures according to the invention. In general, amounts of up to 5 % by weight are sufficient.

Components A and B can be combined in any form, e.g. by homogenizing the melts in an extruder or by intimate mixing of solutions of the two components and subsequent evaporation of the solvent system or precipitation of the polymers.

The molding compositions according to the invention can be injected, pressed or cast in the usual way, for example by means of injection molding machines or extruders at temperatures above the melting point of the molding compositions, preferably between 230 and 280 ^{° C.}

The molding compositions according to the invention can advantageously be used for production are used by heavily used objects, e.g. for power strips, electrical switching elements, ignition distributor components, Covers and bearings for machines, housings for kitchen machines or fan heaters.

Le A 15 436 - 6 -

509827/07 42

Example 1; ■ .... ■■

The following fabrics were dried for 8 hours at 120 ° C:

1 polybutylene terephthalate having an intrinsic viscosity of 120 ml / g, measured in phenol / tetrachloroethane (1: 1) (0.8 ml diameter mm, length 10 cm, flow volume 5) at 25 ⁰ C in an Ubbelohde capillary viscometer

2. Elastomeric segmented mixed polyester (Hytrel 4055 ^ - <

Commercial product of Du having an average molecular weight of 25,000 Pont) - v 30 000 average block lengths: on from 950 to 1,200, expressed as molecular weight, comprising up to about 52 wt .-% of polytetrahydrofuran soft segments (with a glass transition temperature Tempera door position of the mechanical Maximum loss, measured in a torsion pendulum at approx. 1 Hz according to DIN 53 445) of -55 ° C. and approx. 48% by weight from polybutylene tenter hard segments; the melting point of the crystalline fractions was beirul55 ^O C.

3. Elastomeric segmented mixed polyester (Hytrel 5555V_y, commercial product from Du Pont) with an average molecular weight of 25,000-30,000 and average block lengths of 950-1200, indicated as molecular weight, consisting of approx. 39 % by weight of polytetrahydrofuran soft segments with a glass transition temperature (temperature location of the maximum mechanical loss, measured in the torsion pendulum at about 1 Hz according to DIN 53 445) of -55 ° C and about 61 wt -% of PoIybutylenterephthalat hard segments. the melting point of the crystalline fractions was / v206 ° C.

The dried substances 1 and 2 or 1 and 3 were ^{homogenized at 250 °} C. in a 45 mm extruder. The spun off material was granulated and injection molded into test specimens. The results of the technological tests

Le A 15 436 - 7 -

5098 2 7/0 7 42

are summarized in Table 1. Mean:

a _n impact strength at _{± temperature T according to} a _k notched impact strength DIN 53 453

(the specification ng for a and a _k means:
not broken)

Hc ball indentation hardness, measured after 30 seconds. and DIN 53 456

bF

(ZbB ^tzw flexural strength) according to DIN 53 452 f associated deflection)

Modulus of elasticity. according to DIN 53 457

Yield stress)

Tensile strength) according to DIN 53 455 c η elongation at break)

^E train ^E - ^modulus according to DIN 53 457

(ΓSE tension when forming the constriction
/ SE ^to S ^ehöri S ^e stretching
Vicat B heat resistance according to DIN 53 460

Table 1

Technological properties of the blends prepared according to Example 1 of elastomeric segmented copolyesters and Polybutylenterephthalat.Werkzeugtemperaturj 80 ⁰ C, melt temperature 260 ⁰ C.

Le A 15 372 - 8 -

509827/0742

cn ο co oo

Le A 15 Readings 0 Mixed polyester content 2) 6.5 20th 40 - 60 100 salary 10 20th on mixed polyester 3) 60 ' 100 372 A _n (RT) [kJ / mj ¹ n.g. 10- 110 n.g. n.g. n.g. n.g. n.g. n.g. 40 n.g. n.g. a _n (-30) IkJ / m ² ] n.g. 81 n.g. n.g. n.g. n.g. 57 n.g. n.g. n.g. n.g. a _k (RT) | kJ / m ^ | ngng
(4/56> 6.0 15th 24 n.g. n.g. . 6th 11 n.g. n.g. n.g. H _o fi Pal 4.5 2000 80 45 18th 25th 115 100 21 40 18th / TT ₇ , M Pal
[j bF 111 J 135 49 68 50 30th 4.5 83 75 62 40 13th f H 95 43 6.0 6.0 6.0 6.0 6.0 6.0 55 6.0 6.0 I.
VO E _B [Μ Pa] 5.6 27 1640 1160 610 60 2000 1800 6.0 800 185 I. rs L * ^pi 3 2350 11 42 30th 20th 6.8 54 48 1300 28 15th (TSE [j ^P f | 55 110 36 28 19th 6.8 48 40 38 26th 15th isE M 49 2310 28 24 43 44 25th 32 33 45 45 (Tr § ^P 3 26th 167 10 22nd 36 24 22nd 20th 35 46 36 25th 270 410 570 830 82 250 27 550 66C ^E train [? ^P 3 83 1940 I3OO 700 55 232O 2010 380 920 19C Vicat B [ ⁰ CJ 2710 146 103 55 - 172 160 1470 124 72 186 142

With regard to a practical combination of notched impact strength, The mixture of 20% by weight mixed polyester 3) and 80 proved to be tensile strength and heat resistance % By weight polybutylene terephthalate as excellent.

Example 2:

The following substances were dried for ^{8 hours at 120 ° C.:}

1), 2) and 3) as in Example 1;

4) polybutylene terephthalate containing 30% by weight of glass fibers.

The dried fabrics were, as described in Example 1, mixed so that the end products have variable proportions of mixed polyesters, but a constant glass fiber content of Possessed 18 wt%. The results of the technological tests are summarized in Table 2.

Table 2

Technological properties of the glass fiber reinforced blends of elastomeric segmented mixed polyesters and polybutylene terephthalate produced according to Example 2; Glass fiber content 18 wt .-%, mold temperature: 80 ⁰ C, melt temperature: 260 ⁰ C

Le A 15 372 - 10 -

5 0 9 8 27/0742

CJI O CD OO

VJI VjJ

Readings salary on mixed polyester 2) 40 % Content of Mixed polyester 3) a _n (RT) [kJ / m ² ] O 20th 60 20th 40 a _n (-3O ⁰ C) [kJ / m ^] 23 44 64 . 42 52 a, (RT) IkJ / rn ² "! 24 34 24 26th 38 H _c | MPä | 5.5 13th 42 9 13: J- _bF or, (T _bB | M Pa] 175 100 75 110 72 f [mnt 155 120 6.0 125 100 E _B | MPa] 3.4 4.7 7th
1900 4.4 6.0 (J * M Pa
ol_ I 4500 3400 56 3500 ' 2600 (Ta ₁ , \ k Pa]
oü LJ - 75 - 84 69 ^ R [m Paj - - 55 -, ■, - ■ C _R [%] 100 75 13.0 82 67 ^ train ü ^P 3 3.0 6.0 3500 5.3 10.0 Vicat B [ ^o c] 6200 4800 100 5100 4000 207 170 195 173

CD OO CJI

In this case, the blends with the mixed polyester turned out to be 2) as excellent; it was possible to achieve practically the same results as with the mixed polyester - ^) - mixtures are, however, already with half the amount of component A required in Example 1.

Le A 15 572 - 12 -

Claims (4)

Patent claims: Contains% of a linear thermoplastic polyester B, characterized in that the one component of the copolyester Ä and the linear thermoplastic polyester - 1. A thermoplastic molding material containing 5 - 99 wt .-% a, there elastomeric segmented copolyester A and 95-1 wt. B consist of the same ester units and that the other component of the mixed polyester A is largely amorphous in the copolymer and has a glass transition temperature of <0.degree. 2. Thermoplastic molding composition according to claim 1, characterized in that it is a product with 40-70 wt .-% polyethylene terephthalate or polybutylene terephthalate hard segments and 60-30 wt. -% polytetrahydrofuran soft segments and as linear thermoplastic polyester B polyethylene terephthalate or polybutylene terephthalate with an intrinsic viscosity between Contains 20 and 180 ml / g. 3 · Process for the production of a thermoplastic molding compound according to claim 1, characterized in that 5 - 99 wt .-% of the elastomeric segmented mixed polyester A and 95-1% by weight of the linear thermoplastic polyester B per se known way intimately mixed with one another. 4. Use of the thermoplastic molding composition according to claim 1 for the production of highly stressed molded parts such as plug strips, electrical 'switching elements, ignition distributor components, Covers and bearings for machines, housings for kitchen machines, fan heaters etc. Le A 15 372 - 13 - 50 9 827/0 742