JPS606371B2 - New impact-resistant thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an impact-resistant material comprising a styrene copolymer composition reinforced with a rubbery polymer and containing Q,8-unsaturated carboxylic acid anhydride as a copolymer component, and polyamide. The present invention relates to a thermoplastic resin composition.

A-mo resin (acrylonitrile-styrene-phthalene copolymer), impact-resistant polystyrene (rubber-reinforced polystyrene), etc. have high impact resistance, good dimensional accuracy, and excellent moldability. For this reason, it is widely used as a molding material, but 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, polyamide has the drawbacks of large shrinkage during molding, easy occurrence of so-called sink marks or 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 impact resistance of polyamide, ABS
A mixed resin composition with resin has been proposed (Japanese Patent Publication No. 38
-23476), ABS resin and polyamide scratches have poor eye solubility, exhibiting a non-uniform dispersion state as shown in the electron micrograph in Figure 2, and delamination state appears in molded products.
In addition, it has major drawbacks such as a significant decrease in mechanical strength and is not a good molding material.

In addition, the present inventors previously discovered Q, 8 as a material that has the excellent performance of both polystyrene and polyamide.
We proposed a new copolymer in which a styrene copolymer chain containing a monounsaturated carboxylic acid anhydride as a copolymerization component and a polyamide chain are chemically bonded (Tokugan Sho 54-12729).
No. 8, Japanese Patent Application No. 129467/1983).

This new copolymer is a molding material with good dimensional accuracy and moldability, as well as excellent wear resistance, chemical resistance, and heat resistance.
The impact strength is still unsatisfactory. The inventors
The present invention was developed as a result of intensive research to develop a material that has the excellent properties of both polystyrene and polyamide and also has excellent impact resistance.

The present invention provides an impact-resistant thermoplastic resin composition comprising polyamide and a styrene copolymer composition reinforced with a rubbery polymer and containing Q,B-unsaturated carboxylic acid anhydride as a copolymerization component. It is something to do.

The resin composition of the present invention has excellent impact resistance, showing particularly high values in measured notched Izod impact strength,
Furthermore, it is a molding material with excellent dimensional accuracy, molded products, abrasion resistance, chemical resistance, and heat resistance.

As mentioned above, a mixed resin composition of A resin and polyamide has been proposed in order to improve the impact strength of polyamide, but due to its poor compatibility, delamination occurs in molded products. It is difficult to put it to practical use as a molding material because of its poor mechanical strength.

Below, in order to better explain the resin composition of the present invention, it will be compared with a mixed resin composition of ABS resin and polyamide. Particularly striking differences are seen in electron micrographs.

FIG. 1 shows an electron micrograph of a resin composition comprising a rubber-reinforced styrene-maleic anhydride copolymer and polycaprolactam, which is an example of a preferred embodiment of the present invention. In this photograph, uniformly dispersed rubber particles are observed, whereas in the electron micrograph of the mixed resin composition of ABS resin and polycaprolactam shown in Figure 2, the rubber particles are markedly non-uniform. Dispersion and ABS
Significant delamination between the resin phase and the polycaprolactam phase is observed, and a very large difference is seen between the two. Also, when viewed as a molding material, a mixed resin composition of ABS resin and polyamide exhibits a phenomenon of delamination in molded products made by a molding method such as injection molding, and good molded products cannot be obtained.

In the case of the resin composition of the present invention, such a phenomenon is not observed and good molded products can be obtained. Furthermore, the resin composition of the present invention is far superior in mechanical strength such as rigidity and impact resistance. Here, to describe in detail a preferred embodiment of the resin composition of the present invention, the rubber-reinforced styrene copolymer composition containing Q,8-unsaturated carboxylic acid anhydride as a copolymerization component used in the present invention. The mixing ratio of polyamide can be in a wide range of 1 to 99:99 to 1, but is particularly preferably 20 to 99 in terms of dimensional accuracy, abrasion resistance, chemical resistance, heat resistance, etc. of the resulting resin composition.
80: in the range of 80-20.

The rubber-reinforced styrene copolymer composition containing Q,8-unsaturated carboxylic acid anhydride as a copolymerization component used in the present invention is a rubber having appropriate compatibility with the styrene copolymer. Although a reinforced resin composition can be used by mixing the components, it is particularly preferable to use a styrenic compound and a Q,6-unsaturated carboxylic acid anhydride in the presence of a rubbery polymer, and if necessary, these. A pinyl-based graft copolymer composition obtained by polymerizing a mixture of monomers copolymerizable with is used. The vinyl graft copolymer composition used in the present invention can be manufactured by a well-known manufacturing method for manufacturing currently commercially available high-impact polystyrene, ABS resin, and the like. For example, it can be produced by bulk polymerizing or bulk suspension polymerizing a solution obtained by dissolving a rubbery polymer into a monomer mixture while heating. The rubbery polymer used here includes polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer,
Acrylic acid ester polymers, etc. are suitable. As the monomer, styrene, Q-methylstyrene, or various nuclear-substituted styrene derivatives such as methylstyrene, butylstyrene, and chlorostyrene are suitable as the styrene compound, and maleic anhydride as the Q,8-unsaturated carboxylic acid anhydride. acid, methyl maleic anhydride, chloromaleic anhydride, citraconic anhydride, butenyl succinic anhydride, tetrahydrophthalic anhydride, and the like. Furthermore, a comonomer copolymerizable with a styrene compound and Q,8-unsaturated carboxylic acid anhydride can be used as a third component,
Specific examples include unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; alkyl methacrylates such as methyl methacrylate and butyl methacrylate; alkyl acrylates such as methyl acrylate and butyl acrylate; and methacrylic acid, acrylic acid, and the like. These comonomers can be used alone or as a mixture. Particularly preferred monomers as the third component are Q,8-unsaturated carboxylic acid esters such as methyl methacrylate and butyl acrylate, and Q,8-unsaturated carboxylic acid esters are introduced into the styrene copolymer. By doing so, good results can be obtained in that the appearance of the molded product of the resin composition with the polyamide provided by the present invention is improved and the flowability during molding is improved. Although it is not clear what causes this, the introduction of Q,6-unsaturated carboxylic acid ester as a third component into the styrene copolymer improves the compatibility between the styrene copolymer and polyamide. It is presumed that the reaction between the styrene copolymer and the polyamide is improved, and the reaction between the styrene copolymer and the polyamide is uniformly carried out, resulting in a more preferable resin composition. Further, the content of the rubbery polymer in the rubber-reinforced styrene copolymer composition used in the present invention is preferably 2 to 6% by weight.

If the content of the rubbery polymer is too low, the impact strength of the resulting resin composition will be unfavorably improved; if the content of the rubbery polymer is too high, the vinyl graft copolymer composition is difficult to manufacture industrially. Furthermore, in the case of a copolymer consisting of a styrene compound and Q,8-unsaturated carboxylic acid anhydride, the proportion of monomers constituting the styrene copolymer component is 80%
~9% by weight, preferably 88-95% by weight, Q,8-
20-2% by weight of unsaturated carboxylic acid anhydride, preferably 1
2 to 5% by weight, and in the case of a copolymer consisting of a styrene compound, a Q,B-unsaturated carboxylic acid anhydride, and a Q,8 monounsaturated carboxylic acid ester, the styrene compound is 40 to 95% by weight. , Q,8-unsaturated carboxylic acid anhydride 2
~30% by weight, preferably 5-20% by weight, Q,8-unsaturated carboxylic acid esters 2-5% by weight, preferably 5
~5% by weight.

The particularly important structural units in the styrene copolymer component are:
It is the content of Q,8-unsaturated carboxylic acid anhydride and has a great influence on the reactivity with polyamide. A content within the above range provides particularly preferable results in terms of moldability, mechanical strength, and delamination of molded products of the resin composition provided by the present invention. If the content of Q,8-unsaturated carboxylic acid anhydride is too high, the quality of the molded product will deteriorate; if it is too low, the mechanical strength will decrease and delamination of the molded product will occur. It looks undesirable. Suitable examples of the rubber-reinforced styrene copolymer used in the present invention include rubber-reinforced styrene-maleic anhydride copolymer,
Styrene-maleic anhydride-acrylonitrile copolymer, styrene-maleic anhydride-methyl methacrylate copolymer, styrene-maleic anhydride-butyl acrylate copolymer, styrene-maleic anhydride-methacrylic acid copolymer, etc. From the viewpoint of the rigidity of the resin composition with the polyamide provided by the present invention and the fluidity during molding, a rubber-reinforced styrene-maleic anhydride-methyl methacrylate copolymer is particularly preferred. Polyamides used in the present invention include polycaprolactam (nylon-6), polyhexamethylene adipamide (nylon-6,
6), polyhexamethylene sebaamide (nylon-6),
10), 6,6/6,10-nylon copolymer, 6,6
/6-nylon copolymer, etc.

The resin composition of the present invention can be produced by melt-mixing a polyamide and a rubber-reinforced styrene copolymer containing Q,8-unsaturated carboxylic acid anhydride as a copolymerization component.

The melt-mixing can be carried out using a conventional apparatus for melting and thickening resins, such as an extruder, a kneader, or a batho ball mixer. The melt mixing is preferably carried out under a shearing force, and the temperature is 220 to 33,000, preferably 250 to 3,000.
It is 0000. As mentioned in Japanese Patent Application No. 54-127298 and Japanese Patent Application No. 54-129467, when producing the resin composition of the present invention, rubber-reinforced Q,8-unsaturated carboxylic acid anhydride is also used. It is thought that an intermolecular reaction occurs between the styrene copolymer contained as a polymerization component and the polyamide, which is why the uniform dispersion state described above is obtained.

In order to cause such an intermolecular reaction, it is essential that the styrene copolymer contains Q,8-unsaturated carboxylic acid anhydride, and this content will affect the resulting resin composition. has a great influence on the properties of Furthermore, if the styrene copolymer contains Q,8-unsaturated carboxylic acid ester together with Q,3-unsaturated carboxylic acid anhydride, crosslinking reaction during melt kneading is difficult to occur, and production during melt mixing is difficult. It is possible to use a styrene copolymer having a wide range of conditions and a wide range of content of Q,8-unsaturated carboxylic anhydride groups. Moreover, there is a favorable point that the resulting resin composition has good fluidity during molding and the appearance of the molded product is improved. The resin composition provided by the present invention is thermoplastic, and has far superior chemical resistance, heat resistance, and abrasion resistance compared to styrene polymers.
Compared to this, the impact strength, especially the notched Izod impact value, is improved, the shrinkage during molding is much smaller, the degree of moisture absorption is also improved, and the dimensional accuracy is good. It is a suitable molding material in the fields of molded products and precision molded products.

Furthermore, it has improved melt strength compared to polyamide, and can be used in extrusion molding and blow molding, and can be used as films, sheets, bottles, laminates, wire coatings, and foams. Pigments, dyes, heat stabilizers, ultraviolet absorbers, plasticizers, nucleating agents, and the like can be added to the resin composition of the present invention.

In particular, by adding antioxidants such as bisphenols, probionates, and phosphites, and ultraviolet absorbers such as phenyl salicylate, benzophenone, and benzotriazole, weather resistance deterioration is significantly improved. Furthermore, glass fiber, carbon fiber,
It can be used as a composite material by adding aromatic polyamide fibers, fibrous reinforcing agents such as asbestos, and inorganic fillers such as calcium carbonate, talc, zinc oxide, wollastonite, and silica.

In particular, when combined with glass fiber, a molding material with markedly improved heat resistance and good mechanical properties can be obtained. Another desirable feature is that it has much better paintability than glass fiber-reinforced polyamide and glass fiber-reinforced polystyrene. Furthermore, the composite material of the present invention does not cause warping of molded products, which is a major drawback of glass fiber reinforced polyamide, and is an unprecedentedly suitable material for use in the fields of large molded products and precision molded products such as automobile parts and home appliance parts. It becomes a molding material. The glass fiber content in the glass fiber-reinforced resin composition of the present invention is preferably 5 to 6% by weight; if it is more than that, the molding processability is reduced, and if it is less than that, a sufficient reinforcing effect cannot be obtained.

When carrying out the present invention, a styrene copolymer and a polyamide are melt-mixed to obtain a resin composition in the form of a pellet, which is blended with glass fibers, and then melt-mixed in an extruder to form a glass fiber-reinforced resin composition. You can also get

In addition, a pellet-shaped mixture of styrene copolymer, polyamide, and glass fiber is directly put into the hopper of an injection molding machine.
A molded product may be obtained at the same time as the melt-mixing, or a glass fiber-reinforced resin composition may be obtained by melting and thickening the above-mentioned three-way 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, calcium carbonate, talc, titanium oxide, zinc oxide, water, etc. It can also be replaced with an inorganic filler such as magnesium oxide.

Furthermore, the resin composition of the present invention can be blended with other thermoplastic resin compositions.

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. Example 1 A rubber-reinforced styrene-maleic anhydride copolymer (polybutadiene content: 9% by weight, Styrene content: 91% by weight, maleic anhydride content: 9% by weight) 5 parts by weight and polycaprolactam (Amilan CMIO17...manufactured by Toray) 5 parts by weight were mixed in a pellet state, and the temperature was 260%.
Melt kneading was performed using an extruder using CO to obtain a pellet-shaped resin composition.

A test piece was prepared by injection molding from the resin composition obtained here, and the tensile strength, elongation, Wizodt impact strength, and heating deformation temperature were measured by the method described in IS Test Method K6871, and the melt flow index was determined by ASTM. Measured by the method described in Test Method D1238 (23000, 10 kg load condition). The peeling state of the molded product was visually observed after a peeling test was performed by attaching an adhesive tape to the fractured surface of the test piece and then removing it. Comparative Example 1 5 parts by weight of ABS resin (polybutadiene content 30% by weight, styrene content in styrene copolymer 70% by weight, acrylonitrile content 3% by weight) and polycaprolactam (amilan CMIO17... Manufactured by Toray) 50
Parts by weight were mixed in a pellet form and melt-melted in an extruder at a temperature of 26 psi to obtain a pellet-shaped resin composition.

The test was conducted in the same manner as in Example 1. The results obtained in Example 1 and Comparative Example 1 are shown in Table 1.

Table 1 also shows the properties of the rubber-reinforced styrene-maleic anhydride copolymer and Amo resin used. In the case of the resin composition of Example 1 of the present invention, no peeling was observed in the molded product and it had excellent mechanical properties, whereas the resin mixture of Comparative Example 1 showed significant peeling in the molded product. The mechanical properties are also unfavorable. Table 1 Rubber reinforced ST-MA: Rubber reinforced styrene-maleic anhydride copolymer N-S: Polycaprolactam (nylon-6
) Next, the resins obtained in Example 1 and Comparative Example 1 were observed using an electron microscope, and the photographs are shown in FIG. 1 and FIG. 2, respectively.

In the resin obtained in Example 1, the rubber particles were observed to be uniformly dispersed, whereas in the resin of Comparative Example 1, the rubber particles were significantly non-uniformly dispersed, and the ABS
Significant phase separation is observed between the resin phase and the polycaprolactam phase. There is a big difference between the two electron micrographs. Example 2 Instead of the rubber-reinforced styrene-maleic anhydride copolymer in Example 1, a rubber-reinforced styrene-maleic anhydride-methyl methacrylate copolymer (polybutadiene content 9% by weight, styrene copolymer) produced in the same manner was used. Table 2 shows a resin composition with polycaprolactam (Amilan CMIO17) using styrene content of 71% by weight, maleic anhydride content of 9% by weight, and methyl methacrylate content of 2% by weight. It was manufactured in the same manner as in Example 1 using the blend ratio, and its physical properties were tested.

The results obtained are shown in Table 2. Table 2 Rubber-reinforced ST-MA-MMA: Rubber-reinforced styrene-maleic anhydride-methyl methacrylate copolymer The appearance of the molded product is determined by light, and the extent of flow marks is determined by the naked eye Example 3 Monomer mixture and Rubber-reinforced styrene-maleic anhydride-methyl methacrylate copolymer (styrene-butadiene copolymer) obtained by polymerizing a solution of styrene-butadiene copolymer (styrene content 20% by weight) in a solvent under stress. Rubber reinforced styrene anhydride of Example 1 (Jen copolymer content 20% by weight, styrene content 85% by weight, maleic anhydride content 7% by weight, methyl methacrylate content 8% by weight in the styrene copolymer) A resin composition was produced using this instead of the maleic acid copolymer, and physical property tests were conducted.

The results are shown in Table 3. Example 4 Dilarc #250 (ARCO/Po
A test similar to that in Example 1 was conducted using a rubber-reinforced styrene-maleic anhydride copolymer resin manufactured by Lyme Oresha.

The results are shown in Table 3. Example 5 Same as Example 1 except that polyhexamethylene adipamide (Leona 120, manufactured by Asahi Kasei) was used instead of polycaprolactam in Example 1, and the melt-kneading temperature was set to 280 oo. The test was conducted.

The results are shown in Table 3. Example 6 Rubber-reinforced styrene-anhydrous obtained by polymerizing a solution of ethylene-propylene copolymer rubber (Mitsui EPT4021...manufactured by Mitsui Petrochemicals Co., Ltd.) dissolved in a monomer mixture and a solvent under a sieve. The same procedure as in Example 1 was carried out using 50 parts by weight of maleic acid copolymer (ethylene-propylene copolymer rubber content: 7% by weight, maleic anhydride content: 7% by weight) and 5 parts by weight of polycaprolactam (Amilan CMIO17). The test was conducted.

The results are shown in Table 3. Example 7 Instead of the rubber-reinforced styrene-maleic anhydride copolymer in Example 1, rubber-reinforced styrene-maleic anhydride copolymer was used.
Methyl methacrylate copolymer (polybutadiene content 15% by weight, styrene content in styrene copolymer 6% by weight, maleic anhydride content 22% by weight, methyl methacrylate content 1% by weight) A test similar to that in Example 1 was conducted using the same.

The results are shown in Table 3. Table 3 Table 3 (continued) N-6,6: Polyhexamethyleneazibamide (nylon-6,6) Comparative example 2 Substitute for the rubber-reinforced styrene-maleic anhydride copolymer in Example 1. Using a rubber-reinforced styrene-maleic anhydride copolymer with a high maleic acid content (polybutadiene content 15% by weight, styrene content 75% by weight in the styrene copolymer, maleic anhydride content 25% by weight), When melt-kneading with polycaprolactam was performed in the same manner as in Example 1, a significant increase in melt viscosity was observed during the process, and a good thermoplastic resin could not be obtained.

Finally, data on the abrasion resistance and chemical resistance of the rubber-reinforced styrene-maleic anhydride copolymer used in Example 1 and the resin composition of the present invention obtained in Example 1 are shown in Table 4. Abrasion resistance is indicated by the amount of wear (female) determined by a taper abrasion tester, and chemical resistance is indicated by the critical strain (%) at which cracks occur when in contact with the chemical. Furthermore, Table 5 shows the shrinkage rates of the polycaprolactam used in Example 1 and the resin composition of the present invention obtained in Example 1 during injection molding.

The shrinkage rate was measured using a flat plate with 3 side thickness and 15 ribs on each side. Table 6 shows the water absorption rates of polycaprolactam and the resin composition of Example 1. The water absorption rate was measured from the weight increase after the injection molded specimen was immersed in 80 qo warm water for 40 minutes. Fourth
Table 5 Table 6 Example 8, Comparative Examples 3, 4 Resin composition 8 obtained in Example 1 Foundation part [Example 8] or rubber reinforced styrene-maleic anhydride copolymer used in Example 1 8 anchors [Comparative Example 3] or the polycaprolactam 8 mm [Comparative Example 4] used in Example 1 and 2 anchors of glass fiber were mixed, this mixture was put into a pent extruder, and 250 ~
The mixture was strained at a temperature of 27,000 to obtain a pellet-shaped glass fiber reinforced resin composition.

Physical property tests and paintability tests were conducted. 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 performed at 50°C and 98% RH.
The tests were conducted on molded products after conducting a 7-bait-hour moisture resistance test. The results obtained are shown in Table 7. 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. Table 7

[Brief explanation of the drawing]

FIG. 1 shows an electron micrograph of a rubber-reinforced resin composition of the present invention comprising a styrene-maleic anhydride copolymer and polycaprolactam. FIG. 2 shows an electron micrograph of a resin composition consisting of Amo resin and polycaprolactam. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. 1 to 99 parts by weight of a styrene copolymer composition reinforced with a rubbery polymer and containing an α,β-unsaturated carboxylic acid anhydride as a copolymer component and 99 to 1 part by weight of a polyamide. An impact-resistant thermoplastic resin composition consisting of. 2. The styrene copolymer composition comprises 40 to 98% by weight of a monomer mixture containing a styrene compound and an α,β-unsaturated carboxylic acid anhydride in the presence of 60 to 2% by weight of a rubbery polymer. The resin composition according to claim 1, which is a vinyl-based kraft copolymer composition obtained by polymerization. 3 A styrene compound in which the styrene copolymer component in the styrene copolymer composition is 80 to 98% by weight;
% by weight of an α,β-unsaturated carboxylic acid anhydride. 4 A styrene compound containing 40 to 95% by weight of the styrene copolymer component in the styrene copolymer composition;
% by weight of α,β-unsaturated carboxylic acid anhydride;
3. The resin composition according to claim 1 or 2, comprising % by weight of α,β-unsaturated carboxylic acid ester. 5. The resin composition according to claim 4, wherein the styrene copolymer component is a styrene-maleic anhydride-methyl methacrylate copolymer. 6. The resin composition according to any one of claims 1 to 5, wherein the rubbery polymer is a rubbery polymer mainly composed of conjugated diolefin. 7. The resin composition according to any one of claims 1 to 5, wherein the rubbery polymer is a rubbery polymer mainly composed of ethylene and propylene. 8 Impact resistance consisting of 1 to 99 parts by weight of a styrene copolymer composition reinforced with a rubbery polymer and containing α,β-unsaturated carboxylic acid anhydride as a copolymerization component and 99 to 1 part by weight of polyamide A resin composition characterized in that the plastic resin composition further contains glass fiber. 9. The resin composition according to claim 8, wherein the glass fiber content accounts for 5 to 60% by weight of the total composition.