JPS6047304B2 - New thermoplastic resin composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a new thermoplastic resin composition.

Specifically, a copolymer formed by bonding a styrene copolymer chain portion containing an α,β monounsaturated carboxylic acid anhydride as a copolymerization component and a polyamide chain portion, a resin composition comprising a styrene polymer and a polyamide. The present invention relates to a resin composition characterized in that the dispersed state of a polymer dispersed phase in the resin composition is extremely fine. Polystyrene, styrene-acrylonitrile copolymer, ABS resin, etc.
Although it is widely used as a molding material due to its good dimensional accuracy and excellent moldability, there is a need for improved chemical resistance, heat resistance, and abrasion resistance.

Polyamide is also widely used as a molding material because of its excellent chemical resistance, heat resistance, and abrasion resistance. However, polyamides have the drawbacks of large shrinkage during molding, easy formation of so-called whiskers and warpage in molded products, high hygroscopicity, large decrease in mechanical strength due to moisture absorption, and large dimensional changes. be.
In order to improve the hygroscopic properties of polyamide, it has been proposed to melt-mix polystyrene and a styrene-acrylonitrile copolymer (Japanese Patent Publication No. 7384-1973).
These are compatible with polyamide. It is known that the molded product exhibits a delaminated state, and has major drawbacks such as a significant decrease in mechanical strength, and is not a good molding material.

Furthermore, in order to improve the compatibility between polyamide and polystyrene, it has been proposed to add a small amount of a low molecular weight (molecular weight 1000 to 3000) styrene-maleic anhydride water copolymer when mixing polystyrene and polyamide. (U.S. Patent No. 396,683 Eel). The addition of this low molecular weight styrene-maleic anhydride copolymer has slightly improved the compatibility of polyamide and polystyrene4, but it is still not sufficient and the dispersion state is coarse, making it difficult to form complex shapes during injection molding. When a molded product is molded, peeling occurs, resulting in unfavorable mechanical strength. The present inventors have arrived at the present invention as a result of intensive studies aimed at developing a material that has the excellent properties of both polystyrene and polyamide.

The present invention provides a resin composition in which a styrene polymer and a polyamide form a finely dispersed state of 15 microns or less. When the resin composition forms a finely dispersed state of 15 microns or less, no peeling occurs even when molded products with complex shapes are molded by injection molding, making it a desirable molding material. It is what it is. The resin composition provided by the present invention was previously proposed by the present inventors (Japanese Patent Application No. 54-127298, Japanese Patent Application No. 54-129).
No. 467) Contains at least 1% by weight of a novel copolymer formed by chemically bonding a styrene copolymer chain portion 5 containing α,β monounsaturated carboxylic acid anhydride as a copolymerization component and a polyamide chain portion Furthermore, it is composed of styrene polymer and polyamide.

The presence of the above-mentioned new copolymer in the resin composition provides a fine dispersion state, and the dispersion state depends on the content of the new copolymer in the resin composition and the styrene polymer content. By reducing the size of the dispersed particles to 15 microns or less, which is greatly influenced by the composition of
A molding material that does not cause delamination of the molded product, has excellent mechanical strength, has good dimensional accuracy and moldability, and has excellent abrasion resistance, chemical resistance, and heat resistance can be obtained. The content of the new copolymer in the resin composition of the present invention is 15% in the dispersion state.
The amount may be less than microns, but preferably 1% by weight or more, and as the content of the new copolymer increases, the dispersion becomes finer and a more preferable molding material can be obtained.

The parts other than the new copolymer in the resin composition are composed of styrene polymer and polyamide, but the ratio of styrene polymer to polyamide is 0 as long as a fine dispersion state of 15 microns or less is obtained. ~100:100~0
and can be adopted in a wide range. The new copolymer used in the present invention is described in detail in Japanese Patent Application Nos. 127298-1982 and 129467-1980, but α,
It can be easily produced by melt-kneading a polyamide and a styrene copolymer containing a β-unsaturated carboxylic acid anhydride as a copolymerization component.

As stated in the above-mentioned earlier application, in order to produce a preferable new copolymer, α in the styrene copolymer used must be
, the content of β-monounsaturated carboxylic acid anhydride is important;
The content is preferably 2 to 30% by weight, more preferably 40 to 95% by weight of styrene, 2 to 3% by weight of maleic anhydride, and 2 to 3% by weight of methacrylic ester. Styrene-anhydrous male! Inic acid-methacrylic acid ester copolymers, styrene-maleic anhydride copolymers consisting of 80 to 98% by weight of styrene and 2 to 20% by weight of maleic anhydride, and the like are used. In addition, the polyamides used in the production of the new copolymer are polycaprolactam (nylon-6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sebaamide (nylon-6,10), 6, 6/6-nylon copolymer, etc. The ratio of the styrene copolymer chain portion to the polyamide chain portion in the new copolymer is not particularly limited as long as it provides a preferable resin composition of the present invention, but if one of them becomes extremely large or small, It is preferable to avoid such a ratio since it cannot have a favorable effect on dispersibility.

Examples of the styrene polymer used in producing the resin composition of the present invention include polystyrene, styrene-acrylonitrile copolymer, styrene-methacrylate copolymer, high-impact polystyrene, ABS resin, MI3S resin, etc. Polymers used as materials can be used. In addition, in order to obtain a finer dispersion state in the resin composition, α, β monounsaturated carboxylic acid or α
, styrene polymers containing β-monounsaturated carbonic anhydride as a copolymerization component, such as styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer, styrene-maleic anhydride copolymer, styrene-maleic anhydride - Methacrylic acid alkyl ester copolymers and their rubber-reinforced resins are used.

The styrene polymers mentioned above can be used alone or as a mixture. The polyamide used in producing the resin composition of the present invention includes polycaprolactam (nylon-6).
, polyhexamethylene adipamide (nylon-6,6)
, polyhexamethylene sebaamide (nylon-6,10
) 6, 6/6 nylon copolymer itself, etc.

The mixing ratio of the novel copolymer, styrene polymer, and polyamide in the resin composition of the present invention can be freely selected as long as a preferable dispersion state can be obtained. If the amount is too small, it will be difficult to obtain a finely dispersed state, so it is preferable that the new copolymer is contained in the resin composition in an amount of 1% or more by weight.

Further, in order to obtain a finer dispersion state in the resin composition, the content of the new copolymer may be increased. Furthermore, the state of dispersion of the resin composition also varies depending on the type of styrene polymer in the resin composition. The average particle size of the dispersed phase may vary depending on the purpose, but is usually 10 microns or less, preferably 5 microns or less, more preferably 3 microns or less, and most preferably 1 micron or less. The resin composition of the present invention is produced by producing a new copolymer from polyamide and a styrene copolymer containing α,β-monounsaturated carbonic acid anhydride as a copolymerization component, and combining the obtained new copolymer with styrene. It can be carried out by melt-mixing a polymer and polyamide, or by melt-mixing a styrene copolymer, polyamide, or styrene polymer containing α,β-monounsaturated carboxylic acid anhydride as a copolymerization component. It is also possible to obtain the resin composition of the present invention at the same time as producing the new copolymer.

The new thermoplastic resin composition provided by the present invention has much better chemical resistance, heat resistance, and abrasion resistance than styrene resins, and has better shrinkage during molding than polyamide resins. It is a molding material suitable for large molded products, precision molded products, etc. because it has a much smaller amount of water, the degree of moisture absorption has been greatly improved, and it has good dimensional accuracy.

Furthermore, it has improved melt strength compared to polyamide, making it suitable for extrusion molding and blow molding, and can also be used for films, sheets, bottle laminates, wire 5 coatings, etc. It is also preferred as a material for foams and fibers. Pigments, dyes, heat stabilizers, ultraviolet absorbers, plasticizers, nucleating agents, and the like can be added to the resin composition of the present invention. Furthermore, it can be used as a composite material by adding fibrous reinforcing agents such as glass fiber, carbon fiber, aromatic polyamide fiber, and asbestos fθ, and inorganic fillers such as calcium carbonate, talc, zinc oxide, and silica. In particular, when combined with glass fiber, a molding material with markedly improved heat resistance and good mechanical properties can be obtained. A further desirable feature is that it has much better paintability than glass fiber-reinforced polyamide and glass fiber-reinforced styrene resin. In addition, the glass fiber reinforced resin composition of the present invention does not cause warping of molded products as seen in glass fiber reinforced polyamides, and is suitable for the fields of large molded products such as automobile parts and home appliance parts, and precision molded products. This makes it an unprecedentedly suitable molding material. The content of glass fiber in the glass fiber reinforced resin composition of the present invention is 5
The content is preferably from 60% by weight; if it exceeds this amount, the moldability deteriorates, and if it is less than that amount, a sufficient reinforcing effect cannot be obtained.

When carrying out the present invention, it is also possible to produce a resin composition first, blend the resin composition and glass fibers, and melt-mix them using an extruder to obtain a glass fiber reinforced resin composition.

In addition, pellets of styrene copolymer containing α,β monounsaturated carboxylic acid anhydride as a copolymerization component, polyamide, a mixture of styrene polymer and glass fiber were directly put into the hopper of an injection molding machine, and melt-mixed. At the same time, a molded product may be obtained, or a glass fiber reinforced resin composition may be obtained by melt-kneading the above-mentioned four-member mixture in an extruder. 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, or calcium carbonate, talc, titanium oxide, zinc oxide, etc. It can also be replaced with an inorganic filler such as magnesium hydroxide.

Furthermore, other thermoplastic polymers may be blended with the resin composition of the present invention.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Examples 1 to 73 Production of new copolymer 50 parts by weight of 8-styrene-maleic anhydride-methyl methacrylate copolymer (maleic anhydride content: 8% by weight, methyl methacrylate content: 2% by weight) Polycaprolactam (
5 parts of amilan [F]CMlOl7 (manufactured by Toray Industries) were mixed in the form of pellets, and melt-kneaded at a temperature of 260°C.

The obtained resin is a new copolymer consisting of a polymer chain consisting of styrene-maleic anhydride/methyl methacrylate copolymer and a polymer chain consisting of polycaprolactam.)
ivy (confirmed using the analytical method described in Japanese Patent Application No. 127298/1983). Production and physical property tests of the resin composition of the present invention The novel copolymer and styrene polymer obtained above [styrene-maleic anhydride-methyl methacrylate copolymer (maleic anhydride content 5% by weight, methacrylic acid Methyl content 2%); Styrene-methacrylic acid copolymer (
methacrylic acid content: 8% by weight); Styrene-methyl methacrylate copolymer (methyl methacrylate content: 2% by weight);
styrene-acrylonitrile copolymer (Tyryl 8783, manufactured by Asahi Tau); A type of ABS resin (Stylack 8301, manufactured by Asahi Tau); polycaprolactam (Amilan 9CM1017, manufactured by Toray) A resin composition of the present invention was obtained by mixing the following materials (manufactured by Akihabara Corporation) in the proportions shown in Table 1 and melt-kneading the mixture at a temperature of 260°C.

A test piece was made by injection molding from the obtained resin composition, and JI
The tensile strength, Izod impact strength, and heating deformation temperature were measured according to the ASTM test method Dl.
Melt flow and index were measured by the method described in 238 (under 230°C110k9 load condition). The dispersion state of the polymer in the resin composition was observed using an electron microscope, and the peeling state of the molded product was determined with the naked eye after a peel test was performed by attaching an adhesive tape to the fractured surface of the test piece and later removing it. Observed at. The results are shown in Table 1. Comparative Examples 1-3 Polycaprolactam (Amilan/1CM1017) 50
Weight parts and styrene polymer [styrene-methyl methacrylate copolymer (methyl methacrylate content 20% by weight)]
); styrene-acrylonitrile copolymer (Tyryl Kino 783); A type of ABS resin (Stylac Kino 301)] were mixed and melt-kneaded at a temperature of 260'C to form a resin composition. Obtained.

Table 2 shows the results of the same test as in Example 1.
Compared to the resin compositions of the present invention described in Examples 1 to 7, in the resin compositions of Comparative Examples 1 to 3, the dispersion state of the polymer was significantly coarser, and a peeling state was observed in the molded product.

The resin composition of the present invention also has better mechanical strength. Examples 8 to 13 Production of new copolymers A styrene-maleic anhydride copolymer (maleic anhydride content: 5% by weight) was used instead of the styrene-maleic anhydride-methyl methacrylate copolymer of Example 1. A new copolymer was produced in the same manner as in Example 1.

Production and physical property tests of the resin composition of the present invention As described above, the novel copolymer, styrene polymer [styrene-maleic anhydride copolymer (maleic anhydride content: 5% by weight)]
); Styrene-methacrylic acid copolymer, *polymer (methacrylic acid content 8% by weight); Styrene-acrylic acid copolymer (acrylic acid content 8% by weight): Polystyrene (Styron 8683...Asahi Tau ); a type of impact-resistant polystyrene (STYRON 8492...manufactured by Asahi Tau), polycaprolactam (Amylan[F]CMlOl);
7) in the proportions shown in Table 3 and melt-kneaded at a temperature of 260°C to obtain a resin composition of the present invention.

Tests were conducted in the same manner as in Example 1, and the results are shown in Table 3.

Examples 14 and 15 Instead of the styrene-maleic anhydride-methyl methacrylate copolymer of Example 1, styrene-maleic anhydride-
A new copolymer was produced in the same manner as in Example 1 using an acrylonitrile copolymer (maleic anhydride content: 6% by weight, acrylonitrile 20% by weight).

The new copolymer obtained above, styrene polymer* [styrene-acrylonitrile copolymer (Tyryl (base) 783
); ABS resin (Stylac Co., Ltd. 301)] and polycaprolactam (Amilas KCMlOl7) are mixed in the proportions shown in Table 4, and the resin composition of the present invention is prepared by melt-kneading at a temperature of 260°C. I got it.

Tests were conducted in the same manner as in Example 1, and the results are shown in Table 4. Finally, the abrasion resistance of the styrene-acrylonitrile copolymer used in Example 4 and the resin composition of the present invention obtained in Example 4,
Chemical resistance data is shown in Table 5.

Wear resistance is measured by wear A loss (Mg) measured using a taper abrasion tester.
The chemical resistance is expressed as the critical strain (%) at which cracks occur when the chemical is in contact with the material. Also, polycaprolactam used in Example 4.

Table 6 shows the shrinkage rate of the injection molding mouth of the resin composition of the present invention obtained in Example 4. Is the shrinkage rate 3? Thickness, side: 150mg
Measured on a flat plate. Table 7 shows the water absorption rates of polybuprolactam and the resin composition of Example 4. The water absorption rate was measured from the weight increase after the injection molded specimen was immersed in 80°C hot water for 41 hours. The glass fiber reinforced resin composition of the present invention has excellent heat resistance, good paintability, and has mechanical properties similar to those of Example 16. Comparative Examples 4 and 5 8 parts of the resin composition obtained in Example 4 [Example 16], or the styrene used in Example 4
80 parts by weight of acrylonitrile copolymer [Comparative Example 4] or 8 parts by weight of polycaprolactam used in Example 4 [Comparative Example 5] and 20 parts by weight of glass fiber are mixed, and this mixture is put into a vent-type extruder. Then, kneading was performed at 250 to 270'C to obtain a glass fiber reinforced resin composition in the form of pellets.

Physical property tests and paintability tests were conducted. For paintability, after painting the molded product with acrylic paint, its appearance was judged with the naked eye, and for the paint film adhesion test, the molded product was subjected to a 72-hour moisture resistance test at 50°C and 98% RH. It was carried out in The results obtained are shown in Table 8. I can see that it is excellent.

Claims (1)

[Scope of Claims] 1 (a) A polymer chain portion composed of a styrene copolymer containing α,β-unsaturated carboxylic acid anhydride as a copolymerization component and a polymer chain portion composed of polyamide. A copolymer consisting of at least 10% by weight of (b) a styrene copolymer and (c) a polyamide, in which the dispersed phase has a finely dispersed state in which the average particle size of the dispersed phase is 15 microns or less. A resin composition comprising: 2. The resin composition according to claim 1, having an average particle size of 10 microns or less. 3. The resin composition according to claim 2, having an average particle size of 5 microns or less. 4. The resin composition according to claim 3, having an average particle size of 3 microns or less. 5. The resin composition according to claim 4, having an average particle size of 1 micron or less. 6 The styrene copolymer chain portion in copolymer (a) is 80
Styrene-maleic anhydride copolymer consisting of ~98% by weight styrene and 2-20% by weight maleic anhydride or 4
It is characterized by being composed of a styrene-maleic anhydride-methacrylic ester copolymer consisting of 0 to 95% by weight of styrene, 2 to 30% by weight of maleic anhydride, and 2 to 58% by weight of methacrylic ester. A resin composition according to claim 1. 7. Claim 1, wherein the styrene polymer b is one or more selected from the group consisting of styrene-maleic anhydride copolymer and styrene-maleic anhydride-methyl methacrylate copolymer. 6. The resin composition according to item 6. 8. Claims 1 or 6, characterized in that the styrene polymer b is one or more selected from the group consisting of styrene-methacrylic acid copolymers and styrene-acrylic acid copolymers. resin composition. 9. Claim 1 or 6, characterized in that the styrene polymer b is one or more selected from the group consisting of polystyrene, styrene acrylonitrile copolymer, and styrene-methyl methacrylate copolymer. The resin composition described in . 10. Claim 1 or 6, characterized in that the styrene polymer b is one or more selected from the group consisting of ABS resin, MBS resin, and high-impact polystyrene.
The resin composition described in . 11. The resin composition according to any one of claims 1 to 10, which is further reinforced with glass fiber. 12. The resin composition according to claim 10, wherein the content of glass fibers is 60 to 5% by weight of the total composition.