DE1920043B2 - HOMOGENOUS MIXTURES OF POLYAMIDES AND SAPAPONIZED AETHYLENE-VINYL ACETATE COPOLYMERS - Google Patents

Description

I. OH I.
C—
ι C-- I.
H H

exists, and has a molecular weight in the range from 10 ⁴ to 10 ⁵ , and wherein the homogeneous sprayable mixture has a relative solution viscosity (measured on a solution of 1 g of the mixture in 100 ml of m-cresol at 25 ⁰ C in an Ubbelohde viscometer) of at least 2.0.

2. Process for the production of homogeneous injectable mixtures of polyamides and polyolefins, characterized in that the polyamide-forming starting materials are added before the polycondensation or the polyamides during or after the polycondensation a saponified ethylene Vinyl acetate copolymer added.

3. The method according to claim 2, characterized in that polyamide-forming monomers in Presence of the saponified ethylene-vinyl acetate copolymer polycondensed at temperatures of 100-300 ° C.

4. The method according to claim 3, characterized in that one is used as the polyamide-forming monomers Caprolactam used.

5. The method according to claim 2, characterized in that the polyamide with the ethylene-vinyl acetate CopoIymerisat mixed and then extruded.

The present invention relates to new homogeneous injectable mixtures of polyamides and saponified Ethylene-vinyl acetate copolymers and a process for their preparation.

Polyamides, such as polycaprolactam, are characterized by high tensile strength, toughness and rigidity. However, a disadvantage for some uses is the decrease in flexibility at low temperatures.

In order to obtain more flexible polyamides even at lower temperatures, attempts have been made to use polyamides To mix polymers that have a very low glass transition temperature. The properties of such Mixtures, for example of polyamide and polyethylene, are not very satisfactory, since polyamides with other polymers are incompatible and the polymers are therefore difficult to disperse in the polyamide permit.

The dispersibility of polyolefins in polyamides can be increased by adding dispersing agents Preparation of the blends or grafting of polyolefin and polyamide can be improved

It is also known that products with improved Notched impact strength at lower temperatures can be obtained when the polyamides on carboxyl groups Copolymers of ethylene contain grafted polyamide side chains.

It has now been found that mixtures of polyamides and saponified ethylene-vinyl acetate copolymers are obtained like less crystalline polyamide types due to improved flexibility at low temperatures distinguish. At the same time, they show an improved behavior similar to that of the more crystalline types Processing like good demouldability

So there have been found homogeneous injectable mixtures of polyamides and polyolefins the end

a) 70-99.9 wt. ^c / o of a polyamide and

b) 0.1-30% by weight of a saponified copolymer of ethylene and vinyl acetate, 10-40% by weight from recurring units of the formula

H OH

y y —C — c — h

I I

H H

exists, and has a molecular weight in the range from 10 ⁴ to 15 ⁵ , and wherein the homogeneous sprayable mixture has a relative solution viscosity (measured on a solution of 1 g of the mixture in 100 ml of m-cresol at 25 ° C in an Ubbelohde viscometer) of at least 2.0.
In the context of this invention, polyamides are understood to mean those high molecular weight polyamides which are derived from a monoamino monocarboxylic acid having at least 6 carbon atoms or from a salt of a dicarboxylic acid and a diamine. The polycaprolactam is preferably used.

The mixtures should consist of 70-99.9% by weight of polyamide.

The modified polyamides can be produced by hydrolytic polymerisation of the aminocarboxylic acids or their derivatives or the salts of diacarboxylic acids and diamines in the presence of the Copolymers at temperatures of 100-300 ° C. The copolymers can be used together with the polyamide-forming Starting materials are added to the reaction apparatus. However, it has proven to be advantageous Dosing of the copolymers into the slightly viscous polyamide melt at a later point in time proven.

The homogeneous, injectable mixtures can continue to be intensively mixed with the polyamides the copolymers and then extruding this mixture.

The products are molded by z. B. injection molding odei extrusion processed.

example 1

ε-caprolactam is polymerized with 9% by weight of t-aminocaproic acid and 0.09% by weight of glacial acetic acid for 1 hour at 200 ^° C. with stirring in a nitrogen atmosphere. The temperature is then increased to 270 ° C. One hour after this temperature has been reached, 0.1; 1.0 and 5.0% by weight of one

saponified copolymers of ethylene and vinyl acetate with a molecular weight of 20,000 and an OH number of 255 are given. After a further 6 hours, the melt in the form of a bristle is spun in a water bath and gehäckselL The chopped material is extracted four times each 3 times with water of 95 ° C and 24 hours in a vacuum oven at 100 ⁰ C dried the granules are molded to form molded bodies, to which the mechanical properties of the products are measured. The data are compiled in the following table. Number 4 is a comparative product made from pure polycaprolactam.

Serial
No. Content of
Polyolefin, ReL Lsgs.
viscosity Bending bending clamping kp / cm ²
at room at -20 ° C E-Modu] from the
kp / cm ² Bending test, % By weight *? re / (l g / lOöml temp. at room at -20 ° C m-cresol at temp. 25 "C) 1520 1 0.1 3.58 1160 1520 24 400 27 500 2 1.0 3.47 1140 1475 24 500 27 900 3 5.0 3.07 1000 1600 24,000 25 600 4th 0 3.1 1190 24 300 29 800

Example 2

9.5 kg of polycaprolactam with a relative solution viscosity of 3.1, measured on a 1% solution in m-cresol at 25 ° C, with 0.5 kg of a saponified molecular weight of 20,000 and with an OH number of 255 intensely mixed. This mixture is extruded, chopped up and injected into moldings. the Product are characterized by good demoldability and

Copoiymeren from ethylene and vinyl acetate from 25 improved flexibility at low temperatures.

Claims (1)

Patent claims: 1. Homogeneous injectable mixture of polyamide and polyolefin consisting of _a ) 70-99.9% by weight of polyamide and b) 0.1-30% by weight of a saponified copolymer from ethylene and vinyl acetate, from] 0-40% by weight from recurring units the formula