JPS6324622B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition comprising polyphenylene oxide, a rubber-modified alkenyl aromatic polymer, and mineral oil. More specifically, the present invention provides a polyphenylene oxide resin composition having well-balanced heat resistance, mechanical properties, and processability by containing specific amounts of a rubber component and mineral oil. Although polyphenylene oxide is a resin with excellent properties such as heat resistance, chemical resistance, and mechanical and electrical properties, it has drawbacks such as poor moldability and low impact resistance. In order to improve moldability in order to improve moldability, a method of blending a compatible rubber-modified alkenyl aromatic polymer with polyphenylene oxide is well known. However, when attempting to greatly improve impact resistance by increasing the rubber content in a composition containing polyphenylene oxide and this rubber-modified alkenyl aromatic polymer, other important properties such as moldability and tensile strength deteriorate. It has become clear that there is a drastic drop in the price. In other words, it has become necessary to balance heat resistance, mechanical properties, and workability. The present inventors conducted extensive studies aimed at improving this point, and found that a resin composition consisting of polyphenylene oxide, a rubber-modified alkenyl aromatic polymer, and mineral oil has excellent properties.
Furthermore, they have discovered that a resin composition with well-balanced physical properties can be obtained by combining the content of the rubber component and the amount of mineral oil, and have arrived at the present invention. That is, the present invention provides a resin composition with improved moldability, which is composed of polyphenylene oxide, a rubber-modified alkenyl aromatic polymer, and mineral oil. In more detail, 8 to 14 with 20 to 80 parts by weight of polyphenylene oxide (A) and a prebutadiene component as a rubber component.
Rubber-modified alkenyl aromatic polymer containing % by weight
(B) In a resin composition consisting of 80 to 20 parts by weight, (B)
The present invention provides a resin composition with improved moldability, characterized in that the component contains 1 to 10% by weight of mineral oil. Regarding the effect of the present invention, the impact resistance is improved when a large amount of rubber is added to improve the impact resistance, but the impact value does not improve with the addition of the rubber content, and the rubber content remains constant. If the amount is exceeded, the shock value becomes insensitive. However, on the other hand, the tensile strength
The gloss and other properties are significantly reduced, and the practical value is reduced. However, when a specific amount of mineral oil was added to a specific amount of rubber, impact resistance was greatly improved, moldability and gloss were also improved, and deterioration in mechanical properties was reduced. It is well known that adding mineral oil to rubber-modified alkenyl aromatic polymers has improved moldability, but this is unexpected as no significant improvement in impact resistance has been observed. be. The specific amount of rubber content/specific amount of mineral oil content provides a resin composition with a balance of polyphenylene oxide and rubber-modified alkenyl aromatic polymer. Hereinafter, embodiments of the present invention will be specifically described. The polyphenylene oxide of component (A) used in the present invention has the general formula

A polymer having a unit structure represented by [Formula] or a copolymer having two or more of the above structural units as long as it does not practically reduce the basic performance of polyphenylene oxide, such as heat resistance and mechanical properties. and n is 50 or more. R ₁ , R ₂ , R ₃ and R ₄ are hydrogen, halogen, a hydrocarbon group or a substituted hydrocarbon group, a hydrocarbon oxy group or a substituted hydrocarbon oxy group. Specific examples of R ₁ , R ₂ , R ₃ and R ₄ include hydrogen, chlorine, bromine, iodine and other halogen atoms; methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, allyl, phenyl, benzyl, methylbenzyl and substituted hydrocarbon groups such as chloromethyl and bromomethyl; hydrocarbon oxy groups such as methoxy, ethoxy, phenoxy and chloroethoxy, and substituted hydrocarbon oxy groups. Specifically, poly-2,6-dimethyl-1,4-phenylene oxide, poly-2,6-diethyl-1,4-
Phenylene oxide, poly-2,6-dipropyl-1,4-phenylene oxide, poly-2-methyl-6-isopropyl-1,4-phenylene oxide, poly-2,6-dimethoxy-1,4- Phenylene oxide, poly-2,6-diphenyl-
1,4-phenylene oxide, poly-2,6-dichloro-1,4-phenylene oxide, poly-
Polymers such as 2,5-dimethyl-1,4-phenylene oxide, 2,6-dimethylphenol and 2,
3,6-trimethylphenol copolymer, 2,
Examples include copolymers such as a copolymer of 6-dimethylphenol and 3-methyl-6-tert-butylphenol. Furthermore, the polyphenylene oxide of the present invention also includes modified products of the above polymers or copolymers. For example, in the presence of an ethylene-propylene-polyene terpolymer, the formula

Oxidative polymerization of [Formula], formula in the presence of polystyrene

[Formula] is oxidatively polymerized, styrene is polymerized in the presence of polyphenylene oxide polymer or copolymer, polyphenylene oxide polymer or copolymer and styrene are kneaded together with peroxide in an extruder. Examples include those made by reacting with water. Here, the alkenyl aromatic polymer has the general formula

[Formula] (R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen, halogen, hydrocarbon group or substituted hydrocarbon group, hydrocarbon oxy group, substituted hydrocarbon oxy group, R ₆ is hydrogen, These are polymers and copolymers containing 50% by weight or more of an alkenyl aromatic compound (lower alkyl group having 1 to 4 carbon atoms). Specific examples of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ include hydrogen; halogen atoms such as chlorine, bromine, and iodine; hydrocarbon groups such as methyl, ethyl, propyl, vinyl, allyl, benzyl, and methylbenzyl. ; Substituted hydrocarbon groups such as chloromethyl and bromomethyl; Hydrocarbon oxy groups or substituted hydrocarbon oxy groups such as methoxy, ethoxy, phenoxy, and monochloromethoxy. Further, specific examples of R ₆ include hydrogen; lower alkyl groups such as methyl and ethyl. Specific examples of alkenyl aromatic polymers include polystyrene, polychlorostyrene, polyα-methylstyrene, styrene-acrylonitrile copolymer, styrene-α-methylstyrene copolymer, styrene-4-methylstyrene copolymer, Examples include styrene-maleic anhydride copolymer and styrene-methyl methacrylate copolymer, among which polystyrene is particularly preferred. Component (B) of the present invention is a rubber-modified alkenyl aromatic polymer, that is, a rubber dispersed in an alkenyl aromatic polymer matrix. The rubber used here is polybutadiene. A butadiene-styrene copolymer obtained by copolymerizing a small amount of styrene is also included. The amount of rubber used is 8-14% by weight.
More preferably, it is 8.5 to 12.5% by weight. Various methods are known for dispersing this rubber in an alkenyl aromatic polymer, and any of these methods may be used. For example, there are mechanical mixing methods, solution blending methods, etc., and in particular, a method of dissolving rubber in an alkenyl aromatic monomer and polymerizing it is carried out industrially. The rubber dispersed phase usually has an average particle size of 0.5-5μ.
When using a rubber-modified alkenyl resin with a low rubber content, polybutadiene or a polybutadiene-styrene copolymer may be added. When a rubber-modified alkenyl aromatic polymer containing 8% by weight or less of rubber is used, it is necessary to add rubber to bring the total rubber content to 8 to 14% by weight. Mineral oil, which is the most important component of the present invention, is defined as an organic oily substance, and a useful example thereof is white oil. It is a complex mixture of paraffinic and naphthenic saturated hydrocarbons. A variety of white oils are available with a wide range of viscosities. More preferably Whiterex334
(Mobil oil), CP-50 (Idemitsu Kosan), PO-75 (Union Oil), and H-140 (Union Oil). The content of mineral oil in component (B) is 1 to 10% by weight. More preferably, it is 2 to 8% by weight. If it is less than 1% by weight, the fluidity will not be improved sufficiently and the impact strength will be low. Moreover, if it exceeds 10% by weight, the fluidity will be good, but the tensile yield stress and heat distortion temperature will decrease, making it impossible to obtain balanced quality. Any method can be used to add mineral oil. For example, a method of adding it during the production of a rubber-modified alkenyl aromatic polymer, a method of adding it during the production of polyphenylene oxide, a method of adding it when blending polyphenylene oxide and a rubber-modified alkenyl aromatic polymer, or a method of adding it during the production of polyphenylene oxide and a rubber-modified alkenyl aromatic polymer. Examples include a method in which a so-called masterbatch blend is formed by mixing a large amount of mineral oil with nylene oxide or a rubber-modified alkenyl aromatic polymer, and the mixture is added when blending polyphenylene oxide and the rubber-modified alkenyl aromatic polymer. . In addition to the components (A) and (B) described above, the present invention also includes (a) graft polymerization of an alkenyl aromatic group to a polyolefin, an ethylene-fatty acid vinyl copolymer, or an ethylene-unsaturated carboxylic acid ester copolymer. At least one thermoplastic elastomer selected from the group consisting of a block copolymer of a (b)alkenyl aromatic compound and an aliphatic conjugated diene compound, and a hydrogenated product thereof may be added. Examples of polyolefins in (a) include polyalpha-olefins such as polyethylene, polypropylene, and polybutene, ethylene-propylene random copolymers and block copolymers, and ethylene-butene random copolymers and block copolymers. An α-olefin copolymer, an ethylene-propylene-nonconjugated diene terpolymer, or the like is used. Next, as the ethylene-fatty acid vinyl copolymer, one having a fatty acid vinyl content of 60 mol % or less is used. Specific examples of vinyl fatty acids include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate, and the like. Further, as the ethylene-unsaturated carboxylic acid ester copolymer, one having an unsaturated carboxylic acid content of 40 mol % or less is used. Specific examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate,
Examples include acrylic esters such as 2-ethylhexyl acrylate, stearyl acrylate, and glycidyl acrylate; and methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and glycidyl methacrylate. The graft copolymer (a) is obtained by graft polymerizing an alkenyl aromatic compound onto a backbone polymer selected from polyolefins, ethylene-fatty acid vinyl copolymers, and ethylene-unsaturated carboxylic acid ester copolymers. The graft polymerization may be carried out by any of the well-known methods such as suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization (including methods using an extruder in addition to methods using a polymerization tank). It can be manufactured even if In this case, the weight ratio of backbone polymer/alkenyl aromatic compound is preferably used in the range of 1/2 to 20/1. Next, (b) has a structure in which at least one block A consisting essentially of chain units of an alkenyl aromatic compound and at least one block B consisting essentially of chain units of an aliphatic conjugated diene compound are combined and bonded. Any one can be used. In this case, there are no particular limitations on the order of the blocks or the structure, such as linear or star-shaped. Specifically, (AB) _n ,
Examples include those having a linear structure such as (BA) _n , A(BA) _n , and B(AB) _n (m is an integer), and those having a star-shaped structure in which these are combined radially. Examples of the conjugated diene compound constituting B include butadiene, isoprene, 1,3-pentadiene, and the like. (B) also includes those obtained by hydrogenating the rubber portion of this block copolymer. Hydrogenation can be carried out using a hydrogenation catalyst such as nickel or palladium. In addition, in the present invention, commonly used heat stabilizers, flame retardants, pigments, fillers, plasticizers, lubricants,
Additives such as ultraviolet absorbers may be added as long as the physical properties do not change significantly. Furthermore, glass fiber,
Fiber reinforcing agents such as asbestos fibers, carbon fibers, alumina fibers, etc. can also be added. There are no particular restrictions on the blending method, but mechanical mixing using a Banbury mixer, extruder, kneader, roll mill, etc. is suitable. Next, the present invention will be explained using specific examples, but these are illustrative and do not limit the present invention. Examples 1 to 3, Comparative Examples 1 to 2 Concentration in chloroform obtained by oxidative polymerization of 2,6-dimethylphenol: 0.5 g/dl Temperature 25
Polyphenylene oxide, rubber-modified polystyrene, and rubber having a reduced viscosity of 0.59 at °C were granulated at 260 °C using a twin-screw extruder in the proportions shown in Table 1. Injection molding was performed using a Sumitomo Nestal injection molding machine (Neomatsu 47/28) at an injection pressure of 1600 Kg/cm ² and an injection speed.
12 (gauge value) and the cylinder temperature was 260°C (300°C). The characteristics were measured according to the following method. (1)Impact strength (with eyelid notches) ASTM
D256 23℃ (2) Yield strength ASTM D638 23℃ (3) HDT ASTM D648 264psi (18.6Kg/
cm ² ) (4) Gloss ASTM D523-53T 60° (5) Flow length Mold 8 mm wide, 3 mm thick, bar flow mold (mold temperature 80°C) From Table 1, when the mineral oil content is constant, the rubber content is It can be seen that 8 to 14% by weight has high impact and maintains a balance of yield stress, fluidity, and HDT.

[Table] Examples 4 to 7, Comparative Examples 3 to 4 Polyphenylene oxide (same as Example 1),
Rubber modified polystyrene, rubber, mineral oil, _TiO2CB
(Carbon Black) was granulated at 260°C using a twin-screw extruder at the ratio shown in Table 2. This product was injection molded in the same manner as in Example 1 using a test piece manufacturing mold.

[Table] From Table 2, when the rubber content is constant, the mineral oil content is 1~
It is found that 10% by weight provides a high impact composition while maintaining a balance of yield stress, HDT, fluidity, and gloss. Example 8, Comparative Example 5 Polyphenylene oxide (same as Example 1) 50
50 parts of rubber-modified polystyrene with different mineral oil contents were granulated at 260°C using a twin-screw extruder. This product was injection molded. The results are shown in Table 3.

[Table] Rubber modified polystyrene formulation (1) Rubber content 11.8% (2) Rubber type Trans type (uses diene NF-35A) (3) Rubber particle size 2.5μ (4) Gel content 21.0% (5) PS [η] 0.76 dl/g Mineral oil (White Rex 334) was placed in rubber-modified polystyrene in advance. Looking at the examples and comparative examples, when the amount of mineral oil is too large, the yield stress and HDT decrease significantly, resulting in a decrease in practical value. Example 9 Polyphenylene oxide (same as Example 1),
Rubber-modified polystyrene and various additives were granulated at 260°C using a twin-screw extruder, and then injection molding was evaluated. The results are shown in Table 4. Formula of rubber modified polystyrene (1) Rubber content 9.3% (2) Rubber type cis type (3) Rubber particle size 2.5 μ (4) Gel content 20.7% (5) PS [η] 0.08 dl/g (6) Mineral oil 4.4%

[Table] Example 14 Composition of 70-30% by weight of polyphenylene oxide (same as used in Example 1) and 30-70% by weight of rubber-modified polystyrene (same as used in Examples 10-13) 1.5 parts of polyethylene per 100 parts of
When 1 to 10 parts of triphenyl phosphate was added as a flame retardant, a flame-retardant composition with well-balanced physical properties was obtained. Example 15 When 10 to 30 parts of glass fiber was further added in Example 14, a glass fiber reinforced composition with well-balanced physical properties was obtained.

Claims (1)

[Claims] 1 Rubber modified alkenyl aromatic polymer (B) containing 20 to 80 parts by weight of polyphenylene oxide (A) and 8 to 14% by weight of polybutadiene component as rubber components 80
A resin composition with improved moldability, characterized in that component (B) contains 1 to 10% by weight of mineral oil in the resin composition comprising 1 to 20 parts by weight.