JPS6017451B2 - Glass fiber reinforced styrenic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass fiber-reinforced styrenic resin composition that has excellent heat resistance and impact resistance, and improved moldability.

BACKGROUND ART Conventionally, it is well known that glass fibers are blended into a thermoplastic resin as a base material in order to improve the mechanical properties and dimensional stability of the thermoplastic resin. However, in the case of a styrene-based glass reinforced composition using a styrene-acrylonitrile copolymer, mechanical properties such as bending strength and rigidity and heat deformation resistance are improved by adding glass fibers, but the heat deformation resistance is Some types of molded products are still unsatisfactory, and improvements in impact resistance are desired. Furthermore, when reinforcing thermoplastic resins with glass fibers, the method of blending the glass fibers affects the physical properties.

In other words, compositions produced by a dry blend method in which glass fibers are directly mixed with thermoplastic resins cause bridging of the glass fibers during injection molding, which significantly impairs workability.
The resulting molded product has extremely poor dispersion of glass fibers, the surface condition of the molded product is extremely poor, and its physical properties tend to be non-uniform. On the other hand, when a thermoplastic resin is mixed with glass fibers and kneaded into pellets using an extruder, the glass fibers are broken during extrusion and kneading, which reduces the impact resistance of the molded product.

In order to solve the above problems, as described in JP-A-51-37141, a vinyl compound monomer is polymerized in the presence of glass fibers, and the glass fibers are coated with a vinyl compound. A method of blending a glass fiber-containing resin with other reinforcing resins, or a method of bulk polymerizing vinyl compound monomers in the presence of glass fibers as described in Tokubatsu No. 561-38343, followed by suspension polymerization. Methods have been proposed to improve the dispersibility of glass fibers and prevent the glass fibers from being cut during hair training by polymerizing and producing granular polymers in which glass fibers are dispersed. Since monomers are polymerized in the presence of fibers, the manufacturing process is complicated, and this is by no means preferable as an industrial manufacturing method.

As a result of research into reinforcing unsaturated dicarboxylic anhydride-modified styrenic resins with glass fibers with the aim of improving these drawbacks, the present invention unexpectedly found that silane-based reinforcement of unsaturated dicarboxylic anhydride-modified styrenic resins with rubber reinforcement By mixing glass fibers that have been surface treated with a surface treatment agent and melting and kneading them using an extruder, the glass fibers are well dispersed, heat resistance and rigidity are high, and impact resistance is improved rather than reduced. It was discovered that a composition with well-balanced physical properties could be obtained, and the present invention was completed.

That is, the present invention provides a mixed component 10 consisting of 70 to 95 parts by weight of 01 vinyl aromatic compound, 5 to 3 parts by weight of [2] unsaturated dicarboxylic acid anhydride, and 0 to 2 parts by weight of rigid and other vinyl compounds. [41 Conjugated Jene Copolymer 1 to 4]
Copolymer resin 10 consisting of 70 to 95% by weight of a graft copolymer or (1') vinyl aromatic compound and 5 to 3% by weight of an unsaturated dicarboxylic acid anhydride obtained by polymerization in the presence of parts by weight of (2) 95-6% by weight of a mixture of 90-1% by weight of the graft copolymer resin and 5-4% by weight of glass fibers surface-treated with a silane-based surface treatment agent. Heat resistant, characterized by being made by melt-kneading,
This is a glass fiber reinforced styrenic resin composition with excellent impact resistance and improved moldability.

In addition to the high heat deformation resistance characteristic of the rubber-reinforced unsaturated dicarboxylic anhydride-modified styrenic resin, the composition according to the present invention has excellent rigidity and impact resistance and improved moldability due to the inclusion of glass fiber. .

Furthermore, as mentioned above, in the case of the styrene-acrylonitrile-butadiene graft copolymer, the impact strength significantly decreases when glass fiber is added, whereas the rubber-reinforced unsaturated dicarboxylic anhydride-modified styrenic resin of the present invention In the case of , even though the base material contains a conjugated gene-based polymer, the unexpected effect of further improving the impact resistance due to the inclusion of glass fibers can be obtained.

That is, when a styrene-acrylonitrile-butadiene copolymer is used as the base resin, the impact strength decreases from 20k9/skin to 5.0k9/skin, for example, by incorporating 20% by weight of glass fiber. In the case of the rubber-reinforced maleic anhydride-modified styrene resin of the present invention, by blending the same amount of glass fiber, the impact strength is improved from 4.0 kg/kg to 8.9 kg/kg, for example, and the impact resistance is significantly improved. The effect was achieved.

In addition, the composition of the present invention has high rigidity at high temperatures, and has high heat deformation resistance that does not cause deformation of molded products at temperatures around 100 to 120 °C, which cannot withstand general styrene resins. It is a feature.

Furthermore, as an effect of containing the conjugated gene-based copolymer, the difficulty in releasing the molded product from the mold during injection molding can be significantly improved.

For example, the length is 50cm, the width is 5cm, the depth is 6cm and the thickness is 2cm.
When molding a box-shaped molded product with a single taper, the maleic anhydride-modified styrene resin containing 2% by weight of glass fiber is overpacked by approximately 1.8%, making it difficult to remove the molded product from the mold. However, the rubber-reinforced maleic anhydride-modified styrenic resin of the present invention containing the same amount of glass fibers has approximately 2.
Even with a 4% overpack, the molded product can be easily removed from the mold. The rubber-reinforced unsaturated dicarboxylic anhydride-modified styrenic resin of the present invention contains a vinyl aromatic compound, an unsaturated dicarboxylic anhydride, and optionally a vinyl compound copolymerizable with these in the presence of a conjugated polymer. Alternatively, it can be obtained by copolymerization by bulk-suspension polymerization.

Vinyl monomers copolymerizable with vinyl aromatic compounds and unsaturated dicarboxylic acid compounds include acrylonitrile,
methacrylonitrile, acrylic acid and its esters,
Examples include methacrylic acid and its esters. Styrene is suitable as the vinyl aromatic compound, and maleic anhydride is suitable as the unsaturated dicarboxylic anhydride. The rubber-reinforced unsaturated dicarboxylic anhydride-modified styrenic resin of the present invention contains 70 to 95 parts by weight of an aromatic pinyl compound, 5 to 3 parts by weight of an unsaturated dicarboxylic anhydride, and optionally a copolymerizable vinyl monomer. It is composed of 100 parts by weight of a mixed component consisting of 0 to 2 parts by weight and 1 to 4 parts by weight of a conjugated gene copolymer.

That is, in the composition of the vinyl monomer, the content of unsaturated dicarboxylic acid anhydride is 5 to 3% by weight, preferably 5% by weight.
~2G% by weight.

When the content of unsaturated dicarboxylic acid anhydride is less than 5% by weight, the improvement in heat deformation resistance of the finally obtained resin composition is small, and conversely, when the content is more than 3% by weight, the finally obtained resin composition impact resistance does not improve much. Further, the amount of the conjugated gene-based copolymer is 1 to 4 parts by weight, preferably 3 to 15 parts by weight. By containing 1 part by weight or more of the conjugated gene-based copolymer, the release of the molded product from the mold during injection molding of the composition is improved, and when the content is up to 4 parts by weight, the composition Improving impact resistance without adversely affecting heat deformation resistance. The base resin of the composition of the present invention includes not only the above-mentioned rubber-reinforced unsaturated dicarboxylic acid-modified styrenic resin (2), but also the rubber-reinforced unsaturated dicarboxylic acid anhydride-modified styrenic resin and the unsaturated dicarboxylic acid anhydride-modified styrenic resin. Blend resins with modified styrene resins can also be used.

Such an unsaturated dicarboxylic acid-modified styrenic resin contains a monomer consisting of 70 to 95% by weight of a vinyl aromatic compound, 5 to 3% by weight of an unsaturated dicarboxylic anhydride, and, if necessary, a vinyl compound that can be polymerized with these. It is obtained by bulk or bulk-suspension polymerization of a solid mixture. In this case as well, styrene is preferred as the vinyl aromatic compound, and maleic anhydride is preferred as the unsaturated dicarboxylic anhydride. Copolymerizable vinyl monomers include acrylonitrile, methacrylonitrile, acrylic acid and its esters, and methacrylic acid and its esters. As the glass fibers used in the present invention, microfibers having a diameter of 10 to 13 mm are suitable, and are surface-treated with a silane-based surface treatment agent.

A strand in which tens to hundreds of such microfibers are assembled and has a fiber length of 1 to low/m is suitable. As the silane-based glass fiber treatment agent, acrylic silane-based, epoxy silane-based, aminosilane-based and the like are preferred. The amount of glass fiber incorporated in the composition of the invention is between 5 and 4% by weight, preferably between 10 and 3% by weight. If it is less than 5% by weight, the effect of improving rigidity, heat resistance and impact resistance will be small, so the objective will not be achieved;
If the amount is more than 20% by weight, it is not preferable because not only will it become difficult to mix the moat, but the efficiency of adding glass fiber for improving physical properties will be reduced.

The melting and thickening step for obtaining the composition of the present invention can be carried out using a conventional extruder.

That is, the rubber-reinforced resin pellet of the present invention and glass fiber are blended, then melt-kneaded using an extruder under normal extrusion conditions to extrude a strand, and after cooling, a glass fiber-reinforced composition in the form of cut pellets is obtained. The composition of the present invention can be easily molded into a desired shape using a common plastic molding machine, such as an injection molding machine or an extrusion molding machine, and has high impact resistance, rigidity, and heat deformation resistance, and can be molded with an excellent appearance. Goods can be obtained. The present invention will be described below with reference to Examples.

Example 1 and Comparative Example 1 10 parts by weight of a vinyl monomer consisting of 85% by weight of styrene and 15% by weight of maleic anhydride was grafted onto 15 parts by weight of a Gen-based elastomer primary mirror, and 8% by weight of a copolymer resin was mixed with acrylic. Glass fibers surface-treated with silane and concentrated with vinyl acetate resin-based concentration agent (diameter 13A, fiber length 6/
m) 2% by weight was incorporated.

This mixture was melt-kneaded using a four-arm extruder to form pellets, which were then molded using a screw-type injection molding machine to prepare test pieces and various physical properties were measured. For comparison, we also measured the appearance of a resin that did not contain glass fiber.

The physical property values are shown in Table 1. Comparative Example 2 8% by weight of a copolymer resin consisting of 85% by weight of styrene and 15% by weight of maleic anhydride and glass fiber (acrylic silane surface treatment, styrene-based concentration agent, 13 mm, fiber length: 6 skin) 2
% by weight was blended, and melt kneading, test piece molding, and physical property measurements were carried out in the same manner as in Example 1.

The test results are shown in Table 1. Comparative Examples 3 and 4 Copolymer resin 8 in which 100 parts by weight of a vinyl monomer polymer consisting of 7 box weight % styrene and 2 weight % acrylonitrile was grafted onto 30 parts by weight Jen-based elastomer main chain.
2% by weight of glass fibers (diameter: 13 mm, fiber length: 6 skins/kite) that had been surface-treated with acrylic silane and bundled with an acetic acid concentration agent was added to the weight percent of .

Melt kneading and test piece molding were performed in the same manner as in Example 1.

Table 1 shows the physical property measurement results.

The physical properties of the resin without glass fiber were also measured. Example 2 670 parts by weight of a copolymer resin consisting of 85% by weight of styrene and 15% by weight of maleic anhydride and 100 parts by weight of a monomer consisting of 85% by weight of styrene and 15% by weight of maleic anhydride.
80% by weight of a mixed composition of 3 parts by weight of a graft copolymer resin grafted onto 5 parts by weight of a Gen-based elastomer primary mirror was subjected to an acrylic silane surface treatment, and glass fibers (diameter 13r, fiber length 6m/w) 2% by weight was blended.

Melt kneading and test piece molding were performed in the same manner as in Example 1. The physical property measurement results are shown in Table 1. Table 1 Physical properties were measured as follows.

Flexural modulus: Measured based on ASTM-D790 Izod impact strength: Measured based on ASTM-D256 Heat distortion temperature: Measured based on ASTM-D648 Furthermore, using the composition of Comparative Example 2, injection molding was performed to obtain When molding a box-shaped molded product with a depth of 60 cm/w, a thickness of 2 kites/skin, and a punch taper of 1 degree, the molded product will break when removed from the mold due to an overpack of approximately 1.8%. However, it can be seen that when the compositions of Examples 1 and 2 were used, the molded product was easily taken out even at approximately 2.4% overback, and the mold release properties were improved. .

Comparative Example 5 A test piece was prepared using the same machine as in Example 1, except that 2 parts by weight of glass fiber without surface treatment was used in place of the glass fiber surface-treated with acrylic silane used in Example 1. Table 2 shows the results of measuring the physical properties.

Table 2

Claims (1)

[Claims] 1 (1) 70 to 95 parts by weight of vinyl aromatic compound, (2
) 5 to 30 parts by weight of unsaturated dicarboxylic anhydride and (3)
A graft copolymer (A
) or (1') 10 to 90% by weight of a copolymer resin consisting of 70 to 95% by weight of a vinyl aromatic compound and 5 to 30% by weight of an unsaturated dicarboxylic acid anhydride; and (2') the above graft copolymer resin (A). Glass fiber 5 surface-treated with 95-60% by weight of a mixture of 90-10% by weight and a silane-based surface treatment agent
A glass fiber-reinforced styrenic resin composition having excellent heat resistance and impact resistance and improved moldability, characterized by being formed by melt-kneading 40% by weight of