CS257485B1 - Thermoplastic polyamide stifeened with silanized glass fibre - Google Patents

Abstract

The thermoplastic polyamide comprises glass fibers silanized with an aromatic disilane of the formula I, where x represents an integer of 0 or 1, R is ethyl or methyl and M is an epoxide residue dian based resin, n = 0 to 1 and / or its with an aminosilane mixture such as gamma-aminopropyltriethoxysilane.

Description

The present invention relates to a silanized glass fiber reinforced thermoplastic polyamide in an amount of 10 to 50% by weight.

Reinforced polyamides have found wide and continually expanding use as a construction material that constantly replaces traditional materials such as wood, spirals and alloys. In the manufacture of these materials, glass fibers are used as reinforcing fillers, whether in the form of mats, fabrics, rovings or chopped fibers. Significant improvements in the mechanical properties of glass-fiber reinforced thermoplastic polyamide were achieved by using silanized glass fibers using substituted trialkoxysilanes, in particular gamma-aminopropyltriethoxysilane, N, β-bis-beta (hydroxyethyl) -gamma-aminopropyltrietoxysilane and gamma-glycysxypropyltrimetil 3 (U.S. Pat. 498,872).

Generally, the glass fibers used for silanization are produced such that the elementary fibers, most often 6 to 18 microns in thickness, are lubricated by sizing into a strand where the number of elementary fibers is most often in the range of 50 to 20000. In the case of indirect lubrication , as a rule, in the form of fabrics, thermally or by washing off the surface of the fibers. Only after this treatment the fibers are silanized, before being used as reinforcement of different plastics and rubbers.

A more economical method of silaneing the fibers is by using direct lubricants which contain silanes in addition to the textile and technological fiber processing agents.

If this type of fiber is used as a polyamide reinforcement, the lubricating film must have a polar character, which can be characterized by a critical surface tension in the range of 39 to 50 mN.m. Some copolymers of vinyl chloride, vinylodene chloride, polyesters and polyurethanes found by the broadest industrial application. Even if this requirement is met, not every silanized fiber imparts the best mechanical properties to the reinforced polyamide.

Although there are various auxiliary criteria, due to the current knowledge of silanized fiber chemistry, it is not possible to accurately identify one or another type of silanized fibers, but only empirically test them for the production of reinforced plastic and their influence on the physico-mechanical properties of the composite. make their selection. In the field of application of various silanized fibers, it has been found that a number of physico-mechanical properties of the reinforced thermoplastic polyamide are improved using the fibers of the invention.

The invention provides a thermoplastic polyamide reinforced with silanized glass fiber in an amount of 10 to 50% by weight. The principle of the invention is that the glass fibers are silanized with an aromatic disilane of the formula I

OH

CH ₂ CHCH ₂ NH (CH ₂ CH ₂ NH) _x (CH ₂ ) ₃ Si (OR-jJ where x is an integer of 0 or 1, R 4 is methyl or ethyl, M is a structure residue

ABOUT

OH

ABOUT

O - ch ₃ ch ₃ n = 0 to 1, and / or a mixture thereof and an aminosilane of formula II nh ₂ (ch ₂ ch ₂ nh) (ch ₂ ) _{3 s} (or ₂ ) ₃ , (II) wherein represents y an integer of 0 or 1, R 4 methyl or ethyl, in an aromatic disilane: aminosilane weight ratio of 1: 0.02 to 10.

The silanized glass fibers according to the invention improve a number of physical-mechanical properties of the reinforced thermoplastic polyamide, in particular the tensile and flexural modulus. In this way, either the application properties of the reinforced polyamide are improved, or it is possible to produce less weight while maintaining their desired mechanical properties.

The preparation of the reinforced polyamide can be carried out using known methods and equipment. Polyamide melt sheathing of continuous glass fibers is most commonly used. After cooling the melt or removing the solvent, the endless string is granulated. In this case, the length of the granule is most often 5 to 12 mm. Most often, the chopped fibers, typically 4 to 8 mm in length, are mixed with the polyamide melt either in a screw extruder, kneader or calendered together. In addition to these known technologies, the preparation can also be accomplished by anionic polymerization of lactams in the presence of silanized glass fibers.

The invention is further illustrated by way of example.

Example

To prepare the composition! polyamide-6 and chopped glass fibers with a length of 6 mm and an average thickness of 15 microns in a concentration of 30% by weight were used. The polyamide-6 used was dried at 90 ° C for 24 h before mixing with the fiber. The fiber-polymer blend was homogenized on a kneader-granulator at a melt temperature of 247 ° C. The prepared granulate was processed at 260 ° C in an injection molding machine to standard test bodies. Samples of reinforced polyamide-6 were conditioned by the procedure according to ČSN 64 3610. As reinforcement was used glass fiber unsilanized, silanized according to pat. No. 3,498,872 and the fiber of the invention.

A - unsilanized fiber

B-gamma-aminopropyltriethoxysilane

C-cyclohexanylethyltriethoxysilane

D - aromatic disilane having an average molecular weight of 822, of the formula (I), wherein x is 0 and is ethyl

E - composition containing 30% by weight gamma-aminopropyltriethoxysilane and 70% by weight aromatic disilane D

F-composition comprising 50% by weight of N-beta-aminoethyl-gamma-aminopropyltrimethoxysilane and 50% by weight of aromatic disilane with an average molecular weight of 824. of formula (1), wherein x is 1 and is methyl

The silanized fibers used were prepared by applying a composition consisting of 10% by weight of polyurethane dispersion (dry matter 33% by weight), 0.5% silanes, which were hydrolyzed in the presence of 0.2% by weight of acetic acid, to the filament glass fibers. 5% by weight of aminoamide acetate, 0.3% by weight of lithium chloride and the remainder to 100% by weight of water. Unsilanized fiber was prepared by treating the fibers with the composition without the addition of silane. The treated fibers, after drying at 125 ° C for 6 h, were cut to a length of 6 mm. The achieved physical-mechanical properties of the reinforced polyamide-6 are shown in the table.

table

Glass fiber A B C D E F tensile strength (MPa) 39.4 60.6 43.8 61.1 60.6 65.7 elongation (%) 26 27 16 24 21 24 bending strength (MPa) 53.7 75.1 6.2,7 75.7 79.9 82.5 modulus of elasticity in turn (MPa) 3 205 3 163 3 432 3 213 3 912 4 210 modulus of elasticity in bend 4MPa) 2 335 2 608 2 561 2 756 2 784 3 012 notch toughness (Kj / m) 9.6 12.7 7.7 10.8 13,9 ' 10.4 ball hardness (N / mm ² ) 64.2 72.9 59.6 76.7 64.4 65.7

Evaluation of mechanical properties was performed using the following methods. Tensile strength and elongation according to ČSN 64 0605, flexural strength according to ČSN 64 0607, flexural modulus according to ČSN 64 0614, notch toughness according to Charpy method according to ČSN 64 0612 and hardness according to ČSN 64 0619.

Claims (1)

Thermoplastic polyamide reinforced with silanized glass fiber in an amount of 10 to 50% by weight, characterized in that the glass fibers are silanized with an aromatic disilane of the general formula OH ch ₂ chch ₂ nh (ch ₂ ch ₂ nh) _χ (ch ₂ ) ₃ Si (OR-J ₃ where x is an integer of 0 or 1, R 4 is methyl or ethyl, M is a structure residue CH, OH CH, ch ₃ n = 0 to 1, and / or a mixture thereof with an aminosilane of general formula nh ₂ (ch ₂ ch ₂ nh) _y (ch ₂ ) _{3 s} (or ₂ ) ₃ , where y is an integer of 0 or 1, R ₂ methyl or ethyl in an aromatic disilane: aminosilane weight ratio of 1: 0.02 to 10.