JPS6059257B2 - Glass fiber reinforced resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a glass fiber reinforced resin composition.

More specifically, a copolymer formed by chemically bonding a styrene copolymer chain portion containing α,β monounsaturated carboxylic acid anhydride as a copolymerization component and a polyamide chain portion, or a copolymer containing the same. Glass fibers are added to the resin composition in an amount of 5 to 5%. This article relates to a glass fiber reinforced resin composition that has good paintability and high heat resistance.
Conventionally, glass fiber reinforced styrene resins have been widely used as useful molding materials because they have excellent dimensional accuracy, dimensional stability, and rigidity, and are also inexpensive. When a cal molded product is painted, it has the disadvantage that a good appearance cannot be obtained, and furthermore, it has poor thermal properties. Furthermore, although glass fiber reinforced polyamide resin has excellent heat resistance and the appearance of molded products is good, it has major drawbacks such as significant deterioration of physical properties and dimensional changes due to moisture absorption.

In addition, 10 to 40% of polyamide mixed with glass fiber
Japanese Patent Publication No. 48-13944 describes an example in which dimensional change due to moisture absorption of polyamide is improved by incorporating a thermoplastic resin.

However, as stated herein, a major drawback is that when 40% or more of thermoplastic resin is mixed in, the toughness decreases. The present inventors investigated to obtain a glass fiber-reinforced resin that has high heat resistance, good appearance after painting, and excellent coating adhesion, and found that α,β-monounsaturated carboxylic acid anhydride Resin of styrene copolymer and polyamide contained as polymerization components 40-95% by weight and glass fiber 60-5%
It has been found that a glass fiber-reinforced resin composition obtained by melt-mixing % by weight gives very favorable results.

The styrene copolymer used in the present invention has α as a copolymer component.
, β-monounsaturated carbonic acid anhydride.

As shown in Japanese Patent Application No. 54-127298 and No. 54-129467, styrene copolymer chains and polyamide chains are chemically bonded by reacting α,β monounsaturated carboxylic acid anhydride with polyamide while melt-kneading. A new bonded copolymer is produced, resulting in a molding material with excellent mechanical properties, heat resistance, and other performance. The object of the present invention is achieved by combining glass fiber with a novel copolymer in which styrene copolymer chains and polyamide chains are chemically bonded. Furthermore, the present invention can also be achieved by compounding a resin composition comprising the novel copolymer described above and a styrene copolymer and/or polyamide containing α,β monounsaturated carboxylic acid with glass fiber. It was found that the objective was achieved. α
, a copolymer consisting of a styrene copolymer chain portion containing a β-unsaturated carboxylic acid anhydride and a polyamide chain portion, or a resin composition containing the copolymer. Tree. The fat composition gives a molded product a good appearance, and when painted, a desirable appearance can be obtained.

Further, the glass fiber reinforcement significantly improves heat resistance and mechanical properties, and even if the content of the styrene copolymer increases, the mechanical properties do not deteriorate significantly. Against this. do,
When using a resin composition consisting of polystyrene or styrene-methyl methacrylate copolymer and polyamide that does not contain A, β-monounsaturated carboxylic acid anhydride, a peeling state occurs in the molded product and a desirable appearance cannot be obtained. Moreover, it is also inferior in terms of mechanical properties. The copolymer forming the styrene copolymer chain portion of the present invention is a monomer that can be copolymerized with a styrene monomer and an α,β monounsaturated carboxylic acid anhydride, or if necessary with both. It can be obtained by copolymerizing with the addition of

As the styrene monomer, styrene, α-methylstyrene, p-methylstyrene, etc. can be used alone or in combination, and as the α,β monounsaturated carboxylic acid anhydride, maleic anhydride, methylmaleic anhydride, chloro Maleic anhydride and the like are used. Examples of monomers that can be copolymerized with both include methacrylic ester, acrylic ester, acrylonitrile, and the like. Preferred styrene copolymers include styrene-maleic anhydride copolymers,
Examples include styrene-maleic anhydride-methyl methacrylate copolymer. Regarding the composition in the styrene copolymer, it is preferable that the content of α,β monounsaturated carboxylic acid anhydride in the copolymer is 2 to 30 mol%, and if the content is too small, It is unfavorable in terms of heat resistance, mechanical strength, and appearance of the molded product, and if the content is too large, it is unfavorable in terms of moldability.

Furthermore, by introducing methyl methacrylate into the styrene copolymer, favorable effects can be obtained on the moldability of the resulting glass fiber reinforced resin composition and the appearance of the molded product, but the content of methyl methacrylate If the amount is too large, the desirable properties of polystyrene will be lost and the cost will increase, which is not preferable. Particularly preferred examples include a styrene-maleic anhydride copolymer with a maleic anhydride content of 2 to 15 mol%, styrene 40 to 95 mol%, maleic anhydride 2 to 30 mol%, and methyl methacrylate 2 to 58 mol%. % styrene-maleic anhydride-methyl methacrylate copolymer. Suitable polyamides for use in the present invention include polycaprolactam (nylon-6), polyhexamethylene adipamide (nylon-6,6), and polyhexamethylene sebaamide (nylon-6,10).

In addition, in the new copolymer or the resin composition containing the copolymer, which is the base of the present invention, the mixing ratio of the styrene copolymer and polyamide can be varied over a wide range from 1 to 99:99 to 1. However, from the viewpoint of the appearance of the coated product, the adhesion of the coating film, etc., styrene copolymer content of 20 to 8% and polyamide content of 80 to 2% are preferred.

The length of the glass fiber used in the present invention is desirably as long as possible, as long as it is longer than the critical length at which the reinforcing effect appears.
0.4 considering workability during mixing, cutting during molding process, etc.
~6.0TIU! It is preferable that the length of the glass fiber in the final molded product be about 0.2 to 2.0.

There is no need to limit the surface treatment of the glass fibers, and commercially available products that have been subjected to various treatments can be used as they are. Further, the content of glass fiber is preferably 5 to 6% by weight based on the glass fiber reinforced resin composition; if it is more than that, the molding processability decreases, and if it is less than 5% by weight, a sufficient reinforcing effect cannot be obtained. The glass fiber-reinforced resin composition of the present invention has high heat resistance and is a material suitable for painting, and also has remarkable improvement in mechanical properties due to glass fiber reinforcement, and has excellent moldability and dimensional accuracy. Auto parts as large molded products,
It can be widely used in home appliance parts.

In carrying out the present invention, for example, pelletized styrene copolymer and polyamide are mixed in a blender and then melt-mixed through an extruder to obtain pelletized resin.

The obtained resin and glass fibers are mixed in a blender and melt-mixed in an extruder to obtain a glass fiber reinforced resin composition. Alternatively, a pellet-like mixture of styrene copolymer, polyamide and glass fiber may be directly put into the hopper of an injection molding machine to obtain a molded product at the same time as melt-mixing, or the above-mentioned mixture of the three components may be melt-kneaded using an extruder. It is also possible to obtain a glass fiber-reinforced resin composition by carrying out this process. When making a resin composition or a molded article, it is preferable to perform the melt kneading under shearing force, and the temperature is 220 to 3300 C1, preferably 25 C.
0~300'C. The composition of the present invention may be used with additives such as heat or light stabilizers, dyes, pigments, flame retardants, plasticizers, etc., as required. Furthermore, thermoplastic resins that can be mixed with the resin composition of the present invention, such as polystyrene, styrene-acrylonitrile copolymer, and styrene-methyl methacrylate copolymer, to the extent that the performance of the resin composition of the present invention is not significantly impaired. , ABS resin, polycarbonate, polyphenylene ether, etc. can also be blended. In addition, some of the glass fibers in the resin composition of the present invention may be substituted with fibrous reinforcing agents such as asbestos, carbon fibers, aromatic polyamide fibers, potassium titanate fibers, calcium carbonate, talc, titanium oxide, zinc oxide, water, etc. It can also be replaced with an inorganic filler such as magnesium oxide.

Furthermore, in the case of the above-mentioned fibrous reinforcing agent, a molding material with preferable performance can be obtained even if the entire amount is used in place of glass fiber. Next, examples will be shown to explain the present invention in more detail.

Parts indicate parts by weight. Examples 1 to 3, Comparative Example 1 Well-dried nylon-6 (Amiran CMlOl manufactured by Toray)
7) Pellets and styrene-maleic anhydride-methyl methacrylate copolymer (maleic anhydride content 9 mol%,
Methyl methacrylate content 8 mol%) pellets [Example] or polystyrene (Asahi Tau Styron 633) pellets [Comparative Example 1] were mixed in the proportions shown in Table 1,
A pelletized reactant or polymer mixture was obtained through a twin-screw extruder at a temperature of 260°C.

The resin pellets and glass fibers obtained here are mixed in a ratio that will give the glass fiber content shown in Table 1, and this mixture is put into a vented extruder and heated to 250 to 270°C to form glass fiber reinforced pellets. A resin composition was obtained. A test molded article was molded from this composition using an injection molding machine. JIS
Tensile strength, Izod impact strength, and heat deformation temperature were measured according to ASTM test method D79 using the method described in Test method K687l.
Bending strength and bending elastic modulus were measured by the method described in Section 2.
Regarding paintability, after painting the molded product with acrylic paint, its appearance was judged with the naked eye, and the adhesion test of the paint film was conducted at 50°C, 198% RH or higher, and a moisture resistance test for 7 days. This was carried out on a later molded product. The results obtained are shown in Table 1 together with glass fiber reinforced polystyrene and glass fiber reinforced nylon-6. It can be seen that the glass fiber reinforced resin composition of the present invention has high heat resistance, good paintability, and excellent mechanical properties. Examples 4 and 5 Well-dried nylon-6 (Amiran CMlOl manufactured by Toray)
7) Pellets 5 and styrene-maleic anhydride-methyl methacrylate copolymer (maleic anhydride content 9 mol%, methyl methacrylate content 8 mol%) pellets (
Part (a) was mixed and passed through a twin-screw extruder at 260°C to obtain resin pellets.

The pelletized resin and glass fiber obtained here were mixed in a proportion that would give the glass fiber content shown in Table 2, and this mixture was put into a vented extruder and heated at 250 to 270'C.
A pelletized glass fiber reinforced resin composition was obtained. Physical property tests were conducted in the same manner as in Example 1. The results are shown in Table 2.
As the glass fiber content increases, the physical properties significantly improve.
Example 6 In place of the styrene-maleic anhydride-methyl methacrylate copolymer in Example 2, a styrene-maleic anhydride copolymer (maleic anhydride content: 10 mol%) was used, and a glass fiber reinforced resin was similarly prepared. A composition was manufactured and physical property tests were conducted.

The results are shown in Table 2. Example 7 Nylon-6 was used instead of nylon-6 in Example 2.
, 6 (manufactured by Asahi Kasei: Leona 1300S), a similar test was conducted.

The results are shown in Table 2. Furthermore, the paintability of the molded products obtained by injection molding of the glass fiber reinforced resin compositions obtained in Examples 4 to 8 was tested in the same manner as in Example 1. As a result, both the appearance of the painted products and the adhesion of the coating film were excellent. Got the results.

The composition of Example 2 of the present invention was also measured for hygroscopicity, dimensional change due to moisture absorption, molding shrinkage rate, and warpage of the molded product.
Hygroscopicity and dimensional changes due to moisture absorption are 72% when heated to 60°C water.
I Terama, by measuring the weight increase and dimensional change after immersing the test piece.

Claims (1)

[Claims] 1. Resin 40 of styrene copolymer and polyamide containing α,β-unsaturated carboxylic acid anhydride as a copolymerization component
A glass fiber reinforced resin composition obtained by melt-mixing -95% by weight and 60-5% by weight of glass fibers. 2. The glass fiber reinforced resin composition according to claim 1, wherein the resin component comprises 20-80% by weight of styrene copolymer and 80-20% by weight of polyamide. 3. The glass fiber reinforced resin composition according to claim 1, wherein the styrene copolymer is a styrene copolymer containing 2 to 30 mol% of α,β-unsaturated carboxylic acid anhydride as a copolymer component. . 4. The glass fiber reinforced resin composition according to claim 1, wherein the styrene copolymer is a styrene-maleic anhydride copolymer consisting of 85 to 98 mol% styrene and 2 to 15 mol% maleic anhydride. . 5 Styrene containing 40 to 96 mol% of styrene copolymer,
2-30 mol% maleic anhydride and 2-58 mol%
Styrene consisting of methacrylic acid alkyl ester of
The glass fiber reinforced resin composition according to claim 1, which is a maleic anhydride-methacrylic acid alkyl ester copolymer.