JPH0158223B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition with improved mechanical strength and paintability, and more specifically, the present invention relates to a resin composition with improved mechanical strength and paintability, and more specifically, a thermoplastic resin-based resin composition with chemically modified polyolefin and a filler treated with a specific treatment. The present invention relates to a resin composition with improved properties. Various technologies have been developed for the purpose of improving the mechanical strength of thermoplastic resins and secondary processability such as paintability. 54-124049 etc. are known. For example, it is known to obtain a composition by adding a large amount of inorganic filler or organic filler to thermoplastic resin such as polyolefin, but although this composition improves stiffness and heat resistance, it sex,
The tensile strength, bending strength, and appearance of the molded product are significantly reduced, and in particular, the secondary processability is completely unsuitable for practical use. As a method to improve the above-mentioned method, a polar group has been introduced into polyolefin resin, which is a non-polar thermoplastic resin, by reacting it with maleic anhydride, thereby increasing the compatibility with the filler. There is. However, with this method, it is difficult to introduce polar groups, the reaction rate is low, and the physical properties of the resulting resin composition cannot be sufficiently improved. Therefore, the present inventors have conducted extensive research in order to overcome the drawbacks of the above-mentioned conventional techniques and develop a resin composition with excellent physical properties. As a result, they discovered that the objective could be achieved by adding a specially treated filler and a special chemically modified polyolefin to a thermoplastic resin, leading to the completion of the present invention. That is, the present invention provides 100% by weight of a resin mixture consisting of (A) 98 to 80% by weight of a thermoplastic resin and (B) 2 to 20% by weight of a chemically modified polyolefin obtained by chemically modifying polyolefin with a liquid rubber and an unsaturated carboxylic acid or a derivative thereof. The object of the present invention is to provide a resin composition with improved mechanical strength and paintability, which contains 10 to 250 parts by weight of a filler treated with (C) an unsaturated carboxylic acid per part of the present invention. As the component (A), which is the base of the resin composition of the present invention, that is, a thermoplastic resin, various types can be used depending on the use of the composition, such as high-density polyethylene, medium-density polyethylene, and low-density polyethylene. Examples include polyethylene, stereoregular polypropylene, atactic polypropylene, ethylene-propylene copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), polystyrene, polyvinyl chloride, polyvinylidene chloride, polyamide, and the like. In addition, the chemically modified polyolefin, which is component (B) of the composition of the present invention, contributes to improving the surface properties of the composition and improves coating properties. ) or chemically modified with derivatives thereof are preferably used. As the liquid rubber, terminal hydroxylated polybutadiene is suitable. In producing this chemically modified polyolefin, radicals such as benzoyl peroxide are generated by heating a polyolefin such as polypropylene, liquid rubber, and an unsaturated carboxylic acid or its derivative in a solvent such as xylene, toluene, heptane, or monochlorobenzene. The reaction may be carried out using an agent. Details of the production of this chemically modified polyolefin are disclosed in JP-A No. 124049/1983. Furthermore, various types of filler treated with the unsaturated carboxylic acid, which is the component (C) of the composition of the present invention, can be considered, and there are various manufacturing methods. Examples of fillers that can be used here include carbonates, oxides, hydroxides, sulfates, and the like of metals from Group 3 of the periodic table. Specific examples of these are:
Carbonates such as CaCO ₃ , MgCO ₃ , BaCO ₃ , CaO,
Oxides such as MgO, BaO, Al ₂ O ₃ , TiO ₂ , ZnO,
Possible examples include hydroxides such as Ca(OH) ₂ , Mg(OH) ₂ , Al(OH) ₃ and Ba(OH) ₂ , and sulfates such as CaSO ₄ , MgSO ₄ and BaSO ₄ . Furthermore, in addition to these fillers, various textile compounds such as talc, clay, mica, glass fiber, and metal fiber, as well as organic compounds such as wood flour and cellulose, can also be used. In the composition of the present invention, these fillers treated with an unsaturated carboxylic acid are used as component (C), but various types of unsaturated carboxylic acids can be used as the treating agent. However, it is generally an unsaturated carboxylic acid having 10 or less carbon atoms and having a hydrocarbon moiety having one or more ethylenic double bonds and one or more carboxyl groups, especially acrylic acid and methacrylic acid. It is preferable to use acids such as crotonic acid, cinnamic acid, sorbic acid, maleic acid, maleic anhydride, itaconic acid, glutaconic acid, vinyl acetic acid, etc. alone or in combination. When treating the filler with this unsaturated carboxylic acid, it is usually sufficient to simply mix the filler and the unsaturated carboxylic acid at a temperature of 100 to 150°C. The surface of the filler treated in this way is coated with a chemically active unsaturated carboxylic acid, and there is a strong bond between the filler and the unsaturated carboxylic acid, either chemically or physically. This is what we are doing. Instead of adding a filler treated with an unsaturated carboxylic acid, if you add the filler and the unsaturated carboxylic acid to the resin separately, the surface of the filler will not be coated with the unsaturated carboxylic acid, and the unsaturated carboxylic acid will simply be a lubricant. However, the effect of the present invention cannot be obtained. The composition of the present invention basically consists of each of the components (A), (B) and (C), and is usually prepared by heating and melting and mixing these components. During such mixing, the active groups of the unsaturated carboxylic acid coating the filler and the active groups of the chemically modified polyolefin act synergistically on the thermoplastic resin that is the base of the composition, resulting in (A), ( B) and (C) The compatibility and dispersibility of each component are improved, and as a result, a composition with excellent mechanical strength and molded appearance can be obtained. It is also believed that when this composition is molded, the above-mentioned reactive groups are extruded onto the surface of the molded product, and the resulting molded product can form a strong chemical bond with the paint. In the composition of the present invention, the blending ratio of each component (A), (B), and (C) varies depending on the purpose of use of the composition and other conditions, and cannot be unambiguously determined. Filler 10 treated with unsaturated carboxylic acid to 100 parts by weight of a resin mixture consisting of ~80% by weight and 2-20% by weight of chemically modified polyolefin
It is preferable to mix it in a proportion of ~250 parts by weight. If the blending ratio of chemically modified polyolefin and filler to the thermoplastic resin is outside the above range,
The improvement in mechanical strength and paintability of the composition is not sufficient, and it is difficult to say that it is preferable. In addition to the above components (A), (B), and (C), the composition of the present invention may optionally contain a radical generator such as an organic peroxide, an azo compound, an inorganic peroxide, or an organic tin compound. It is also effective to add various additives such as stabilizers, plasticizers, lubricants, crosslinking agents, pigments, flame retardants, and antistatic agents. The composition of the present invention thus obtained not only has excellent rigidity and heat resistance, but also has high tensile strength and
Various mechanical strengths such as tensile modulus, bending strength, flexural modulus, and impact strength are greatly improved compared to conventional compositions, and the molded products obtained by molding this composition have a beautiful appearance. In addition, its paintability is extremely excellent. Therefore, the composition of the present invention can be effectively and widely used in members that require strength such as light electrical appliances, automobile parts, and audio products, or in coated products such as furniture and lacquerware. Next, the present invention will be explained in more detail with reference to Examples. Examples 1 to 20 and Comparative Examples 1 to 18 (1) Production of filler treated with unsaturated carboxylic acid. After mixing 10 kg of the specified filler and 100 g of the specified unsaturated carboxylic acid kept at 40 to 50°C for 30 minutes in a stainless steel container at a temperature of 120 to 140°C, the resulting suspension is washed with methanol. The filler was further dried at 80° C. to obtain a filler treated with an unsaturated carboxylic acid, component (C) of the present invention (hereinafter referred to as "treated filler"). (2) Production of chemically modified polyolefin. 100 parts by weight of polypropylene (melt index 8 g/10 minutes, density 0.91 g/cm ² , trade name: J700G, manufactured by Idemitsu Petrochemical Co., Ltd.) was placed in a three-neck separable flask with an internal volume of 5 and equipped with a stirring blade and a reflux device. 1,4-polybutadiene with terminal hydroxylation (number average molecular weight 3000, product name: Poly bd
R45HT, manufactured by ARCO chem.Div.), 20 parts by weight of maleic anhydride, 1.72 parts by weight of dicumyl peroxide, and 600 parts by weight of xylene.
The mixture was heated in an oil bath using an immersion heater and reacted with stirring at 120°C for 1 hour, and then continued at 140°C for 3 hours. After the reaction is completed, cool
The mixture was precipitated into a large excess of acetone, filtered under suction, and dried (at 70°C for 50 hours) to obtain a white powder. Subsequently, this powder was placed in a Soxhlet extractor and extracted with acetone for 16 hours to remove unreacted polybutadiene and maleic anhydride to obtain a chemically modified polyolefin, which is component (B) of the present invention. (3) Manufacture of resin composition. The prescribed thermoplastic resin, the chemically modified polyolefin obtained in (2) above, and the treated filler obtained in (1) above were kneaded for 5 minutes at a resin temperature of 230°C using a Banbury mixer to determine the resin composition. I got something. (4) Molding of resin compositions and measurement of physical properties of molded products. The resin composition obtained in (3) above was heated to 210℃ using an injection molding machine (Niigata Iron Works, SN160).
ASTM standard specimens were prepared by molding at a mold temperature of 50°C, and the physical properties of these specimens were measured. The results are shown in the table.

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Claims (1)

[Scope of Claims] 1. A resin mixture consisting of (A) 98 to 80% by weight of a thermoplastic resin and (B) 2 to 20% by weight of a chemically modified polyolefin obtained by chemically modifying a polyolefin with a liquid rubber and an unsaturated carboxylic acid or a derivative thereof. (C) Filler treated with unsaturated carboxylic acid 10 per 100 parts by weight
-250 parts by weight of a resin composition with improved mechanical strength and paintability. 2 (A) The thermoplastic resin is high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, ethylene-propylene copolymer, acrylonitrile-butadiene-styrene copolymer,
The composition according to claim 1, which is polystyrene, polyvinyl chloride, polyvinylidene chloride or polyamide. 3 The unsaturated carboxylic acid used to treat the filler is acrylic acid, methacrylic acid, crotonic acid, cinnamic acid,
The composition according to claim 1, which is sorbic acid, maleic acid, maleic anhydride, itaconic acid, glutaconic acid or vinyl acetic acid or a mixture thereof.