JPH0225931B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a resin composition obtained from a polyamide and an unsaturated carboxylic acid ester copolymer containing an imide compound of an α,β-unsaturated dicarboxylic acid as a copolymerization component. Specifically, the present invention provides a bond between a polymer chain portion composed of an unsaturated carboxylic acid ester copolymer containing an imide compound of α,β-unsaturated dicarboxylic acid and a polymer chain portion composed of polyamide. The present invention relates to a method for producing a resin composition containing a novel copolymer. Polymethyl methacrylate, methyl methacrylate-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, etc. are widely used as molding materials because of their good dimensional accuracy and excellent moldability. However, there is a demand 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 a large shrinkage during molding, causing "sink marks" on molded products.
It is prone to warping and is highly hygroscopic.
It has the drawbacks of a large decrease in mechanical strength due to moisture absorption and a large dimensional change. In order to improve the hygroscopic properties of polyamide, it was proposed to melt-mix polystyrene and styrene-acrylonitrile copolymer (Japanese Patent Publication No. 40-7380).
However, it is known that these materials have major drawbacks such as poor compatibility with polyamides, molded products exhibit delamination, and mechanical strength is significantly reduced, so they are not good molding materials. ing.
In addition, in order to improve the compatibility between polyamide and polystyrene, when mixing polystyrene and polyamide, a small amount of low molecular weight (molecular weight 1000 to 3000)
It has been proposed (US Pat. No. 3,966,839) to add a styrene-maleic anhydride copolymer.
Although the addition of this low molecular weight styrene-maleic anhydride copolymer improves the compatibility between polyamide and polystyrene, it is still not sufficient, and when molded products with complex shapes are molded by injection molding. Peeling occurs, resulting in unfavorable mechanical strength. In addition, low molecular weight (molecular weight ~ 1500) styrene-
The reaction between a maleic anhydride copolymer and an alkylamine is shown in US Pat. Nos. 3,365,399 and 3,444,151. However, the product is a low molecular weight compound and is only used as an additive, a dispersant, etc., and there is no example of its use as a molding material. Furthermore, in the reaction of polymer compounds,
It is generally well known that the reactions of low molecular weight compounds cannot be directly applied to high molecular weight compounds due to their low reactivity and the tendency for crosslinking reactions to proceed. Furthermore, for the purpose of improving the impact resistance of polyamides, it has been often proposed to incorporate carboxyl group-containing olefin polymers or copolymers of olefins and acrylic esters into polyamides. However, in such cases, as stated in Japanese Patent Publication No. 42-12546, the terminal groups of polyamide and acid groups do not cross-bond or graft, but ionic hydrogen bonds occur. believed to be an interaction. The present inventors also obtained a molding material with excellent mechanical strength by combining a styrene-methacrylic acid copolymer or a styrene-methyl methacrylate copolymer containing a carboxyl group in the copolymer with a polyamide. I couldn't do it. Furthermore, from the results of analytical experiments, it has been found that a copolymer formed by bonding a styrene-methacrylic acid copolymer chain portion and a polyamide chain portion, or a copolymer formed by bonding a styrene-methyl methacrylate copolymer chain portion and a polyamide chain portion. No formation of a copolymer was observed. The present inventors have arrived at the present invention as a result of intensive studies aimed at developing a material that has the excellent performance of both unsaturated carboxylic acid ester polymers and polyamides. The resin composition provided by the present invention is a molding material that is thermoplastic and has good moldability, and has excellent mechanical strength, dimensional accuracy, abrasion resistance, chemical resistance, and heat resistance. Furthermore, when a copolymer of a long-chain alkyl ester such as butyl acrylate is used as the unsaturated carboxylic acid ester, a resin composition with flexibility and excellent impact strength can be obtained. That is, the present invention provides an unsaturated carboxylic acid ester copolymer comprising an α,β-unsaturated carboxylic acid ester, an imide compound of an α,β-unsaturated dicarboxylic acid, and a monomer copolymerizable with both. It is a combination, and each component contains X mole, Y mole, and Z mole, respectively, and the relationship between X, Y, and Z is formula (1), formula (2), and formula (3). Mol% (1) Y/X + Y + Z x 100 = 1 to 30 mol% (2) Z/X + Y + Z x 100 = 0 to 49 mol% (3) Unsaturated carboxylic acid ester copolymer and polyamide having the following composition The present invention provides a method for producing a resin composition obtained by melt-kneading the following. Below, in order to better explain the new copolymer contained in the resin composition obtained by the production method of the present invention, a comparison will be made with a mixture of a methyl methacrylate copolymer and a polyamide (hereinafter referred to as a mixture). I will explain. First of all, when solvent fractionation (cresol/methyl ethyl ketone system) is performed, the mixture completely separates into methyl methacrylate copolymer and polyamide, whereas the novel copolymer of the present invention can be fractionated. This indicates that the unsaturated carboxylic acid ester copolymer containing the imide group of dicarboxylic acid and the polyamide are chemically bonded to each other. Next, looking at the electron micrograph, the resin composition of the present invention contains a novel copolymer in which an unsaturated carboxylic acid ester copolymer chain portion containing an imide group of dicarboxylic acid and a polyamide chain portion are bonded. In the photograph, fine particles of 5 microns or less are observed, whereas in the photograph of the mixture of methyl methacrylate-styrene copolymer and polyamide, coarse particles of 10 microns or more are observed. , the difference is remarkable. As a result of studying the remarkable difference in the dispersion state described above, the present inventors found that a polymer chain consisting of an unsaturated carboxylic acid ester copolymer and a polymer chain consisting of polyamide are chemically bonded to each other. The resin composition containing the copolymer exhibits a finely dispersed state in which the average particle size of the dispersed phase is 5 microns or less, but in the case where no reaction between polymers occurs, and when the styrene-acrylonitrile copolymer and polyamide, It has also been found that when the reaction between polymers in combinations such as methyl methacrylate-styrene copolymer and polyamide does not occur, only a coarse dispersion state in which the average particle size of the dispersed phase is greater than 5 microns can be obtained. Also, when viewed as a molding material, if no reaction occurs between polymers, for example, resin mixtures obtained by melt-kneading styrene-acrylonitrile copolymer and polyamide, methyl methacrylate-styrene copolymer and polyamide, etc. In resin mixtures obtained by melt-kneading with
The mechanical strength of the molded product is also poor, making it impossible to obtain a good molded product. On the other hand, in the case of a resin composition containing a new copolymer in which an unsaturated carboxylic acid ester copolymer chain portion obtained by causing an intermolecular reaction and a polyamide chain portion are bonded, The molded product obtained by the injection molding method does not exhibit delamination phenomenon and can be a good molded product with excellent mechanical strength. The composition of the unsaturated carboxylic acid ester copolymer containing an imide compound of α,β-unsaturated dicarboxylic acid as a copolymerization component used in the present invention is as follows:
α,β-unsaturated carboxylic acid ester 50-99 mol%, imide compound of α,β-unsaturated dicarboxylic acid 1-30 mol%, α,β-unsaturated carboxylic acid ester and α,β-unsaturated dicarboxylic acid The monomer copolymerizable with the imide compound is preferably selected from the range of 0 to 49 mol%. Particularly important is the imide group content of the dicarboxylic acid, which has a large effect on the reactivity with polyamide. A content within the above range gives particularly preferable results in terms of the mechanical strength of the resin composition of the present invention. The unsaturated carboxylic acid ester copolymer can be produced by conventional bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization techniques that utilize radical polymerization, as described in Canadian Patent No. 847,437.
The unsaturated carboxylic acid ester copolymers used in the present invention include non-rubber-reinforced copolymers and impact-resistant rubber-reinforced copolymers. Examples of the α,β-unsaturated carboxylic acid ester for forming the copolymer used in the present invention include methacrylic acids such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. ester, ethyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, 2-ethyl acrylate
Acrylic esters such as hydroxyethyl or mixtures thereof are used. The imide compound of α,β-unsaturated dicarboxylic acid has the following formula:

It can be represented by the following formula: (wherein R ₁ , R ₂ , and R ₃ represent hydrogen, an alkyl group, an alkenyl group, a cycloalkyl group, a phenyl group, a phenylene group, an alkylene group, etc.). For example,
Maleimide, N-methylmaleimide, N
-Butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N
-(P-methylphenyl)maleimide, N-
(3,5-dimethylphenyl)maleimide,
N-(P-methoxyphenyl)maleimide,
N-benzylmaleimide, N-(1-naphthyl)maleimide, and the like. Monomers that can be copolymerized with α,β-unsaturated carboxylic acid esters and imide compounds of α,β-unsaturated dicarboxylic acids include styrene compounds such as styrene, α-methylstyrene, and vinyltoluene, and acrylonitrile. , α,β-unsaturated nitriles such as methacrylonitrile, α,β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid, monoolefins such as ethylene, propylene, and isobutene, vinyl acetate, and vinyl ether. The rubber-reinforced unsaturated carboxylic acid ester copolymer used in the present invention includes polybutadiene rubber,
Polymerizing the monomer in the presence of a rubbery polymer such as styrene-butadiene rubber, polybutene rubber, hydrogenated styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene rubber, polyacrylate rubber, natural rubber, etc. It is obtained by As the unsaturated carboxylic acid ester copolymer suitable for use in the present invention, methyl methacrylate-N
- phenylmaleimide copolymer, methyl acrylate-N-phenylmaleimide copolymer,
Butyl acrylate-N-phenylmaleimide copolymer, methyl methacrylate-N-phenylmaleimide-styrene copolymer, butyl acrylate-N-phenylmaleimide-styrene copolymer, methyl methacrylate- Examples include N-phenylmaleimide-acrylonitrile copolymer and butyl acrylate-N-phenylmaleimide-acrylonitrile copolymer. Suitable polyamides used in the present invention include nylon 6 (polycaprolactam), nylon 6/6 (polyhexamethylene adipamide), nylon 6/10,
These include nylon-11, nylon-12, a copolymer of terephthalic acid and trimethylhexamethylene diamine (Trogamid T...manufactured by Dynamit Nobel), and the like. The resin composition provided by the present invention contains a novel copolymer formed by bonding an unsaturated carboxylic acid ester copolymer chain portion and a polyamide chain portion as described above, and contains a novel copolymer and a polymer chain portion. It is composed of a mixture of polyamide and an unsaturated carboxylic acid ester copolymer containing dicarboxylic acid imide groups that have not undergone intermolecular reaction. The content of the novel copolymer in the resin composition is 10% by weight or more, preferably 50% by weight or more. The resin composition provided by the present invention is thermoplastic, and has far superior chemical resistance, heat resistance, and abrasion resistance compared to unsaturated carboxylic acid ester polymers, and is far superior to polyamide. The shrinkage during molding is much smaller, the degree of moisture absorption is greatly improved, and the dimensional accuracy is good, making it a suitable molding material in the fields of large molded products and precision molded products. Furthermore, it has improved melt strength compared to polyamide, making it suitable for extrusion molding and blow molding, and can be used for films, sheets, bottles, laminates, wire coatings, etc.
It is also preferred as a material for foams and fibers. Pigments, dyes, heat stabilizers,
It can be used by adding ultraviolet absorbers, plasticizers, nucleating agents, etc. In particular, by adding antioxidants such as bisphenols, propionates, and phosphites, and UV absorbers such as phenyl salicylate, benzophenones, and benzotriazoles, the deterioration of weather resistance of resin compositions can be significantly suppressed. Ru. 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, 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 polymethyl methacrylate. In addition, the composite material using the resin composition of the present invention does not have warpage of molded products, which is a major drawback of glass fiber reinforced polyamide, and can be used for automobile parts, etc.
It is an unprecedentedly suitable molding material for use in the fields of large molded products such as home appliance parts and precision molded products. Furthermore, the resin composition of the present invention may contain other thermoplastic polymers, polymethyl methacrylate, methyl methacrylate-styrene copolymer, styrene-acrylonitrile copolymer, ABS resin, MBS resin, impact-resistant polystyrene rubber. It is also possible to use a blend of a graft polymer obtained by grafting an α,β-unsaturated carboxylic acid ester onto a polymer. The resin composition of the present invention is produced by reacting an unsaturated carboxylic acid ester copolymer containing an imide compound of an α,β-unsaturated dicarboxylic acid as a copolymerization component with a polyamide during melt-kneading. be able to. The reaction during melt-kneading can be carried out in a kneader, a Banbury mixer, a twin-screw extruder, or other equipment that melts and kneads resin, but melt-kneading must be carried out under a sufficiently high shear force. If the force is weak and melt-kneading is insufficient, reactions between polymers will be less likely to occur. temperature is 220
-330°C, preferably 260-300°C. If the melt-kneading temperature is too low, the reaction will be difficult to occur, and if the temperature is too high, thermal decomposition of the polymer will occur, which is undesirable. The shear force and temperature conditions during melt-kneading are important points in producing the resin composition of the present invention. Furthermore, a reaction promoter may be added to accelerate the reaction during melt-kneading. The content of dicarboxylic acid imide groups in the unsaturated carboxylic acid ester copolymer containing the α,β-unsaturated dicarboxylic acid imide compound used here is important; If it is too large or too small, the reactivity with the polyamide will not be appropriate, and a resin composition with desirable mechanical strength will not be obtained. It is known that a reaction occurs between the polymers when an unsaturated carboxylic acid ester copolymer containing an imide compound of an α,β-unsaturated dicarboxylic acid as a copolymerization component and a polyamide are melt-kneaded. This can also be recognized from the fact that the resin composition of the present invention exhibits a viscosity higher than the melt viscosity and solution viscosity of either the unsaturated carboxylic acid ester copolymer or the polyamide before reaction. On the other hand, a mixture of methyl methacrylate-styrene copolymer and polyamide exhibits a melt viscosity and solution viscosity intermediate between that of the methyl methacrylate-styrene copolymer and polyamide before mixing, and the melt viscosity and solution viscosity Additivity is observed. 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, Comparative Example 1 Polycaprolactam (Amilan CM1017...
Toray) 50 parts by weight and ηsp/C = 0.85 (m-cresol/methyl ethyl ketone = 9/1 mixed solvent, 30
50 parts by weight of methyl methacrylate-N-phenylmaleimide-styrene copolymer (N-phenylmaleimide content 7 mol%, styrene content 20 mol%) [Example 1] or ηsp /C
= 1.05 methyl methacrylate-styrene copolymer (styrene content 20 mol%) 50 parts by weight [Comparative Example 1]
were mixed in the form of pellets, and melt-kneaded using a twin-screw extruder at a temperature of 260°C. The following tests were conducted on the reaction product of polycaprolactam and methyl methacrylate-N-phenylmaleimide-styrene copolymer obtained here, and the mixture of polycaprolactam and methyl methacrylate-styrene copolymer. Ivy. (1) Observation using an electron microscope When observing the reaction product of the methyl methacrylate-N-phenylmaleimide-styrene copolymer of the present invention and polycaprolactam using an electron microscope, fine particles with a size of 2 μm or less are observed. On the other hand, in the mixture of methyl methacrylate-styrene copolymer and polycaprolactam, coarse particles of about 10μ in size were observed.
A state of incompatibility of the polymers is observed. (2) Solvent fractionation experiment Weighed 10 g each of the reaction product from methyl methacrylate-N-phenylmaleimide-styrene copolymer and polycaprolactam and the mixture of methyl methacrylate-styrene copolymer and polycaprolactam, It was dissolved in a mixed solvent of cresol and methyl ethyl ketone (9/1). The solution was added to a large amount of methyl ethyl ketone to completely form a precipitate. Separate the precipitate and use it as a polymer (). In the case of the reaction product, the weight of the polymer () was 8.2 g, and in the case of the mixture, the weight of the polymer () was 5.0 g. The dissolved polymer was recovered from the remaining solution. This is called polymer (). In the case of the reaction product, the weight of the polymer () was 1.6 g, and in the case of the mixture, the weight of the polymer () was 4.6 g. Furthermore, infrared spectrum analysis of Polymer () and Polymer () was conducted. In the case of the reaction products, both Polymer () and Polymer () showed spectra of both methyl methacrylate-N-phenylmaleimide-styrene copolymer and polycaprolactam. On the other hand, in the case of mixtures, the spectrum of polymer () matched that of polycaprolactam, and the spectrum of polymer () matched that of methyl methacrylate-styrene copolymer. From this solvent fractionation experiment, methyl methacrylate-
It is clear that a copolymer in which the N-phenylmaleimide-styrene copolymer and polycaprolactam are bonded is produced. A test piece was made by injection molding from the reaction product and mixture, and the tensile strength, Izot impact strength, and heating deformation temperature were measured using the method described in JIS test method K6871.
According to the method described in ASTM test method D1238 (230℃,
Melt flow index was measured (under 3.8Kg 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 later removing it. Also, the solution viscosity was measured. The results are shown in Table-1. The solution viscosity of the reaction product is significantly increased over both polycaprolactam (ηsp/C=1.25) and methyl methacrylate-N-phenylmaleimide-styrene copolymer. On the contrary, such a phenomenon is not observed in the case of mixtures. Examples 2 to 5 Methyl methacrylate-N-phenylmaleimide copolymer (ηsp/C=0.92, N- phenylmaleimide content 5 mol%), methyl methacrylate-N-phenylmaleimide-acrylonitrile copolymer (ηsp/C=0.96, N-phenylmaleimide content 10 mol%, acrylonitrile content 10 mol) %), methyl acrylate-N-phenylmaleimide copolymer (ηsp/C=0.85, N
-Phenylmaleimide content 7 mol%), butyl acrylate-N-phenylmaleimide-
A styrene copolymer (ηsp/C=0.92, N-phenylmaleimide content 5 mol%, styrene content 20 mol%) was melt-kneaded in the same manner as in Example 1 to form a reaction product. I got something. The solvent fractionation experiment described in Example 1 was carried out, and a copolymer formed by bonding an α,β-unsaturated carboxylic acid ester copolymer chain and a polycaprolactam chain was confirmed in all reaction products. Further, according to electron microscopic observation, fine particle dispersion state of 2μ or less was observed. Example 6 In place of polycaprolactam in Example 1, polyhexamethylene adipamide (Leona
1200S...manufactured by Asahi Kasei) to adjust the melt-kneading temperature.
A reaction product was obtained in the same manner as in Example 1 except that the temperature was 280°C. In this case as well, a copolymer formed by bonding an α,β-unsaturated carboxylic acid ester copolymer chain and a polyhexamethylene adipamide chain was confirmed by a solvent fractionation experiment. The results of the physical property tests are shown in Table-1. Example 7 80 parts of the reaction product obtained in Example 1 and 20 parts of glass fiber
This mixture was put into a vented extruder and kneaded 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. 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℃ and 98%RH.
The molded product was subjected to a 72-hour moisture resistance test as described above. The obtained results are shown in Table 2 together with glass fiber reinforced polymethyl methacrylate and glass fiber reinforced nylon-6. The glass fiber reinforced resin composition of the present invention has high heat resistance, good paintability,
Furthermore, it can be seen that the mechanical properties are also excellent.

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Claims (1)

[Claims] 1 (a) α,β-unsaturated carboxylic acid ester,
imide compound of α,β-unsaturated dicarboxylic acid,
An unsaturated carboxylic acid ester copolymer containing a monomer that can be copolymerized with both,
Contains X moles, Y moles, and Z moles of each component, and the relationships among X, Y, and Z are formulas (1), (2), and (3). Y/X+Y+Z×100=1 to 30 mol% (2) Z/X+Y+Z×100=0 to 49 mol% (3) An unsaturated carboxylic acid ester copolymer having the composition shown below, (b) polyamide and , A method for producing a resin composition by melt-kneading.