KR100385368B1 - Styrene-based thermoplastic composite material with improved impact strength - Google Patents

Abstract

PURPOSE: A styrene-based thermoplastic composite material is provided, to improve impact strength and mechanical strength by enhancing the interface adhesive strength of a matrix resin and a reinforcing agent. CONSTITUTION: The styrene-based thermoplastic composite material comprises 1-50 parts by weight of the modified vinyl aromatic graft copolymer obtained by melting and mixing 0.01-2 parts by weight of an organic peroxide and 0.1-10 parts by weight of a reactive monomer containing an unsaturated carboxylic acid or its anhydride with 100 parts by weight of the graft copolymer obtained by graft polymerizing 20-99 parts by weight of an aromatic vinyl-based monomer to 50-95 parts by weight of a styrene-based thermoplastic resin, 5-50 parts by weight of an inorganic reinforcing agent and 1-80 parts by weight of a rubbery polymer. Preferably the inorganic reinforcing agent is selected from the group consisting of glass bubble, glass bead, carbon fiber, talc, silica, mica, alumina and a silane sheaving agent-chopped glass fiber.

Description

Styrene-based thermoplastic composites with improved impact strength

The present invention, in the styrene-based thermoplastic composite material reinforced with glass fibers, by using a modified vinyl aromatic graft copolymer for the styrene resin and glass fibers, the interfacial adhesion between the resin of the matrix and the glass fibers of the reinforcing material is improved and the impact strength And a styrene-based thermoplastic composite having improved mechanical strength.

In general, the thermoplastic resin has a disadvantage in that it is insufficient to be used as a material for parts requiring high strength and precision because of low dimensional stability, creep resistance, heat resistance, and rigidity. In order to solve this problem, a method of manufacturing a thermoplastic composite material using an inorganic filler such as glass fiber as a reinforcing material has been proposed. One of the most important techniques in such a method is to increase the interfacial bonding force between the reinforcing material and the resin. . This is because when the interfacial bonding force between the resin and the reinforcing material is lowered, the stress applied to the thermoplastic composite material acts on the interface between the resin and the reinforcing material, so that the fracture progresses around the interface, and thus the desired rigidity increase effect cannot be obtained. Therefore, a method of coating the surface of the reinforcement with a material containing a reactive group capable of reacting with the resin in order to improve the interfacial adhesion between the resin and the reinforcement has been reported in US Pat. No. 3,671,378 and US Pat. No. 4,405,727. However, these methods are excellent in the case of the polyamide resin, the polyester resin, and the polycarbonate resin in which the matrix resin contains the reactivity, but the mechanical properties are improved when the non-reactive styrene resin is used as the matrix. There is a disadvantage that is difficult to expect.

As another example, PCT patent application WO86 / 05445 has an interface between a resin and a reinforcing material by coating a reinforcing material with a rubbery intermediate layer containing a reactor capable of reacting the reinforcing glass fiber with the reinforcing glass fiber, and having a reactor capable of reacting with the reinforcing glass fiber. Although a method of improving the bonding force has been proposed, this method has the inconvenience of coating the glass fiber with a rubbery polymer through a separate process. European Patent No. 485793 does not coat the surface of the reinforcing material through a separate process, but adds a rubbery graft copolymer including a tertiary alkyl ester group to improve the interfacial adhesion between the styrene resin and the reinforcing material. Researchers have been made to improve the physical properties of composite materials by improving the interfacial adhesion between resin and glass fiber, such as a composite material using acrylonitrile-butadiene-styren ecopolymer (ABS) resin as a matrix resin. It's going on.

When the modified vinyl aromatic graft copolymer is used in the styrene-based thermoplastic composite material, the inventors have found that the interface adhesion between the resin and the reinforcing material can be improved to produce a styrene-based thermoplastic composite material having improved impact strength.

That is, the present invention improves the interfacial bond between the resin constituting the matrix and the glass fiber as the reinforcing material by using the modified vinyl aromatic graft copolymer to provide a styrene-based thermoplastic composite material having improved impact strength and mechanical strength.

The present invention relates to 100 parts by weight of a graft copolymer obtained by graft polymerization of 20 to 99 parts by weight of an aromatic vinyl monomer to 50 to 95 parts by weight of a styrene thermoplastic resin, 5 to 50 parts by weight of an inorganic reinforcing material and 1 to 80 parts by weight of a rubbery polymer. Styrene-based thermoplastic composite comprising 0.01 to 2 parts by weight of an organic peroxide and 0.1 to 10 parts by weight of a reactive monomer containing an unsaturated carboxylic acid or an anhydride thereof and 1 to 50 parts by weight of a modified vinyl aromatic graft copolymer subjected to grafting reaction. It is about the material.

Hereinafter, the present invention will be described in more detail.

Styrene-based thermoplastic resin used in the present invention is 50 to 95 parts by weight, polystyrene, high impact polystyrene (HIPS), polychlorostyrene, polyalpha-methylstyrene, polyt-butylstyrene and the like and copolymers thereof alone Or a mixture of two or more thereof, and it is preferable to use double polystyrene or high impact polystyrene. The molecular weight of the styrene resin is also not particularly limited, but considering the thermal stability and workability of the resin composition, the weight average molecular weight is preferably 20,000 to 50,000.

The inorganic reinforcing material used in the present invention is a glass fiber, glass bubble, glass bead, carbon fiber, talc, silica, mica, alumina, etc. General inorganic filler of 5 to 50 parts by weight is used.

The modified vinyl aromatic graft copolymer used in the present invention has an organic peroxide of 0.01 to 2 based on 100 parts by weight of the graft copolymer obtained by graft polymerization of 20 to 99 parts by weight of an aromatic vinyl monomer to 1 to 80 parts by weight of a rubbery polymer. It is manufactured by melt kneading by kneading reaction with 0.1-10 weight part of reactive monomers containing a weight part and unsaturated carboxylic acid or its anhydride group, and is used in the amount of 1-50 weight part with respect to the whole resin composition. The rubbery polymer may be a ternary copolymer of a diene rubber, an ethylene rubber, and an ethylene / propylene / diene monomer, and an average particle diameter of rubber particles of the rubbery polymer may be 0.02 to 1.0 μ, and preferably 0.05 to 0.5. μ. If the average particle diameter of the rubber particles is 0.02μ or less, it is difficult to prepare a graft copolymer, and if it is 1.0μ or more, the effect of improving compatibility through proper morphology is hardly seen.

Aromatic vinyl monomers include styrene, para t-butylstyrene, alpha-methylstyrene, beta-methyl styrene, p-methylstyrene, vinyltoluene, vinylxylene, monochlorostyrene, dichlorostyrene, dibromostyrene, chlorostyrene, In ethyl styrene, vinyl naphthalene, divinybenzene, etc., Preferably, styrene and alpha-methyl styrene are preferable.

The method for preparing the graft copolymer may be any of emulsion polymerization, suspension polymerization or bulk polymerization. Preferably, the aromatic vinyl monomer is added in the presence of a rubbery polymer and emulsion polymerization is performed by adding a polymerization initiator. Or bulk polymerization is preferable.

Organic peroxides used in the preparation of the modified vinylaromatic copolymer of the present invention include diisopropylbenzenehydroperoxide, di-t-butylperoxide, p-methanehydroperoxide, t-butylcumylperoxide, dicumylperoxide , 2,5-dimethyl 2,5-di (1-butylperoxyhexane, di-t-butyldiperoxyphthalate, succinic acid peroxide, t-butyldiperoxybenzoate, t-butylperoxymaleic acid, t-butyl Peroxyisopropyl carbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, etc. may be used, and these may be used alone or in combination of two or more, and in consideration of double reactivity and processability, dicumyl peroxide is used. It is desirable to.

The organic peroxide is preferably used in an amount of 0.01 to 2 parts by weight, but when mixed at 2 parts by weight or more, the thermal stability and physical properties of the final resin composition are significantly reduced due to decomposition of the resin.

Examples of the reactive monomer containing an unsaturated carboxylic acid or anhydride group thereof used in the preparation of the modified vinyl aromatic graft copolymer of the present invention include maleic anhydride, maleic acid, itaconic anhydride, fumaric acid, acrylic acid, and methacrylic acid esters. Although it can be used, it is preferable to use double maleic anhydride.

Although it does not specifically limit about the method of manufacturing the modified vinyl aromatic graft copolymer which graft-modified the reactive monomer which has the said unsaturated carboxylic acid or its anhydride group, but considering that a working temperature is comparatively high, it is a vinyl aromatic graft air. It is preferable to carry out graft reaction in melt-kneading state using a subvane mixer or a vented extruder incorporating a copolymer, an organic peroxide and a reactive monomer.

The addition amount of the unsaturated carboxylic acid or the reactive monomer having an anhydride group to the vinyl aromatic graft copolymer is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total vinyl aromatic graft copolymer. When the added amount is less than 0.1 part by weight, there is little effect of improving the compatibility of the final resin composition. When the added amount is 10 parts by weight or more, the production process of the modified vinyl aromatic polymer becomes difficult and the compatibility with the matrix decreases, Mechanical properties are significantly lowered.

The modified vinyl aromatic graft copolymer of the present invention is used 1 to 50 parts by weight, preferably 3 to 30 parts by weight. If the amount of the modified vinyl aromatic graft copolymer is 1 part by weight or less, there is little effect of improving the compatibility of the resin composition of the present invention, and if it is 50 parts by weight or more, the heat resistance of the resin composition is lowered.

Although the present invention will be described in more detail with reference to the following examples, the present invention is not limited by the following examples.

Examples 1-4

Styrene resin (A) uses HI-1180, a product of Cheil Industries Co., Ltd., and is an inorganic reinforcing material (B) of chopped glass fiber (10μ diameter, 3mm in length, treated with silicone-based binding agent). glass fiber) was used.

In addition, the modified vinylaromatic graft copolymer (C) contains 300 g of polybutadiene latex (based on solids) and 700 g of styrene having a rubber particle diameter of 0.1 µ in a reactor, and 5 g of potassium persulfate 5 g and 5 g of mole are added to the mixture. The graft copolymer was prepared by emulsion polymerization by adding sodium phosphate. The number of such graft copolymers, maleic anhydride and dicumyl peroxide mixed in the composition (unit: parts by weight) shown in Table 1, L / D = 30. Pellets polymers C ₁ , C ₂ , C ₃ , C ₄ were prepared using a single screw extruder having a diameter of 30 mm. At this time, the cylinder temperature was set at 150 to 250 ° C., and the rotation speed of the screw was 100 rpm.

TABLE 1

As shown in Table 2, the above materials were prepared while changing the contents of the composite components (A), (B) and (C) of the present invention.

In order to reduce the cutting of glass fibers, the components (A) and (C) are first mixed with a Henschel mixer, and a twin screw extruder with L / D = 34 and φ = 40 mm is used at a temperature of 220 to 280 ° C. and a screw speed of 200 rpm. In the molten state, the component (B) was introduced into the middle of the extruder to prepare pellets. The pellets were dried at 80 ° C. for 4 hours and then injected into a mold at a molding temperature of 220 to 280 ° C. and a mold temperature of 40 to 80 ° C. in a 60z injection machine.

TABLE 2

TABLE 3

Comparative Examples 1 to 3

As shown in Table 4, one or more components of the thermoplastic composite material components (A), (B) and (C) were excluded or prepared and the composition was changed. At this time, the extrusion, injection and physical property measurement methods are the same as in Example, and 0.2 parts by weight of an antioxidant and a heat stabilizer were respectively added.

TABLE 4

TABLE 5

Property evaluation method

① Tensile strength: measured by ASTM D638.

② Flexural modulus: measured by ASTM D790.

③ impact strength: measured by ASTM D256.

As a result of Table 5, if the glass fiber content is 5 parts by weight or less, there is no reinforcing effect of mechanical strength, and the impact strength is remarkably lowered unless the modified vinyl aromatic graft copolymer is added.

According to the present invention, by using the modified vinyl aromatic graft copolymer in the styrene-based thermoplastic composite material, the interfacial adhesion between the resin and the reinforcing material is improved, thereby obtaining a styrene thermoplastic composite material having improved impact strength.

Claims (7)

50 to 95 parts by weight of the styrene-based thermoplastic resin, 5 to 50 parts by weight of the inorganic reinforcing material and 1 to 80 parts by weight of the graft copolymer obtained by graft polymerization of 20 to 99 parts by weight of the aromatic vinyl monomer to the rubber polymer Styrene-based thermoplastic composite material consisting of 1 to 50 parts by weight of a modified vinylaromatic graft copolymer, which is kneaded by melt kneading and reacting with 0.1 to 10 parts by weight of a reactive monomer containing 0.01 to 2 parts by weight of a peroxide and an unsaturated carboxylic acid or an anhydride thereof. . The method of claim 1, wherein the styrene resin is selected from the group consisting of polystyrene, high impact polystyrene, polychlorostyrene, polyalpha-methylstyrene, polyt-butylstyrene, and copolymers thereof, or a mixture of two or more thereof. Styrene-based thermoplastic composite material. The rubber polymer of the graft copolymer is selected from the group consisting of diene rubber, acrylic rubber and rubber of ternary copolymer of ethylene-propylene-diene monomer, and the average particle diameter of rubber particles is 0.02. Styrene-based thermoplastic composite material, characterized in that from 1.0μ. The method of claim 1, wherein the aromatic vinyl monomer of the graft copolymer is styrene, t-butylstyrene, alpha-methylstyrene, p-methylstyrene, vinyltoluene, monochlorostyrene, dichlorostyrene, dibromostyrene, ethyl Styrene-based thermoplastic composite material, characterized in that selected from styrene, vinyl naphthalene, divinylbenzene. The styrene-based thermoplastic composite material according to claim 1, wherein the reactive monomer containing a carboxylic acid or anhydride group thereof is selected from the group consisting of maleic anhydride, fumaric acid, acrylic acid and methacrylic acid ester. The method of claim 1, wherein the organic peroxide is diisopropylbenze hydroperoxide, di-t- butyl peroxide, p- methane hydroperoxide, t- butyl cumyl peroxide, dicumyl peroxide, 2,5-dimethyl- 2,5 di (t-butylperoxy) hexane, di-tbutylperoxyphthalate, peroxysuccinate, t-butylperoxymaleic acid, t-butylperoxybenzoate, t-butylperoxyisopropylcarbonate Styrene-based thermoplastic composite material, characterized in that selected from the group consisting of methyl ethyl ketone peroxide, cyclohexanone peroxide. The method of claim 1, wherein the inorganic reinforcing material is selected from the group consisting of glass, glass beads, carbon fiber, talc, silica, mica, alumina, glass fiber treated with a silane binding agent, etc. Thermoplastic composite materials.