KR0161504B1 - Thermoplastic resin compositions - Google Patents

Abstract

The present invention relates to a thermoplastic resin composition, and more particularly, it is made of a graft copolymer having a rubbery particle size of an optimum physical property, a copolymer obtained by bulk copolymerization of an aromatic vinyl compound and a vinyl cyanide compound, a polyol, and the like. The present invention relates to a thermoplastic resin composition having excellent gloss and whiteness.

Description

Thermoplastic resin composition

The present invention relates to a thermoplastic resin composition, and more particularly, a graft copolymer having a rubbery particle size of an optimum physical property, a copolymer obtained by bulk copolymerization of an aromatic vinyl compound and a vinyl cyanide compound, and a polyol. The present invention relates to a thermoplastic resin composition having improved gloss and whiteness.

In general, in the housing and automotive parts of household electrical appliances, a resin having a good appearance such as surface gloss and impact resistance is required. Until now, acrylonitrile-butadiene-styrene resin (hereinafter referred to as ABS resin) is mainly used. come. However, in recent years, the use of these resins is diversified and should be used for molded articles of complex shapes, and high-quality products require high whiteness and sharpness of resins. Accordingly, in order to obtain a white resin, a natural pigment, that is, a resin is prepared by adding a white pigment to an uncolored resin, but a decrease in physical properties occurs due to an excessive addition of an inorganic pigment, and the sharpness is lowered to obtain a high white resin. it's difficult. Therefore, methods for producing resins having high gloss characteristics without deterioration of physical properties have been studied. As examples, Japanese Patent Publication Nos. 62-59726 and 61-203158 disclose a bulk polymerization method for the production of ABS resins. To improve the whiteness. However, the physical properties of the prepared resin, in particular, impact strength and glossiness is reduced, because it is difficult to control the particle size of the rubber. In addition, Japanese Patent Publication No. 50-17227 used an emulsification polymerization service to improve the impact strength and attempted a bulk polymerization method as a polymerization method, but the impact strength was slightly improved, but the physical properties of the resin rather than the ABS resin produced by general emulsion polymerization. This was degraded. In addition, oxidative stabilizers were added before extrusion to improve thermal stability, but this could not be a fundamental solution. In Japanese Patent Application Laid-Open No. 62-201959, the emulsion-polymerizing method minimizes the particle size of the rubbery polymer to give glossiness of appearance, and then provides impact resistance by changing the composition of the graft copolymer or the gel content and composition of the rubbery elastomer. However, the thermoplastic resin produced by such a method imparts the impact resistance of the appearance according to the manufacturing method, but the thermoplastic resin produced by such a method according to the manufacturing method, the gloss and mechanical properties of the appearance, in particular impact resistance and Improvement effects such as formability are insufficient. In addition, the above-mentioned thermoplastic resin composition had a severe change in physical properties by adding an additive during the copolymerization.

Therefore, the present inventors have made efforts to solve the problems of physical properties and gloss of the conventional thermoplastic resins as described above, through the graft copolymer, the bulk polymerization by adjusting the particle size distribution of the rubber during the manufacture of the rubber polymer graft body The resin composition of the present invention was developed to have a natural color whiteness and glossiness by using a diffuse reflection of light due to a difference in refractive index between the resin and a polyol by adding a copolymer of a prepared aromatic vinyl compound and a vinyl cyanide compound.

An object of the present invention is to provide a thermoplastic resin composition having excellent overall physical properties including impact strength and improving whiteness and glossiness.

Hereinafter, the present invention will be described in detail.

In the thermoplastic resin composition,

(A) 40 to 70% by weight of the graft copolymer of conjugated diene rubber, aromatic vinyl compound and vinyl cyanide compound,

(B) 30 to 60 wt% of the copolymer of the aromatic vinyl compound and the vinyl cyanide compound, and 100 parts by weight of the copolymer mixture of (a) and (b)

(C) 0.1 to 2.0 parts by weight of a polyol having a molecular weight of 2,000 to 4,000 and

(D) It is characterized by consisting of 0.01 to 2.0 parts by weight of an oxidation stabilizer.

In addition, the graft copolymer (A) has a particle size distribution of 0.15 ~ 0.40 ㎛ 70 ~ 90% conjugated diene rubber 30 to 70% by weight, aromatic vinyl compound 20 to 40% by weight and vinyl cyanide compound 10-30 Characterized in that weight percent.

In addition, the copolymer (b) of the present invention is characterized in that it is prepared by bulk polymerization of 70 to 80% by weight of aromatic vinyl compound and 20 to 30% by weight of vinyl cyanide compound.

Referring to the present invention in more detail as follows.

The present invention relates to a thermoplastic resin composition having high impact and high gloss, wherein the thermoplastic resin composition of the present invention is not mixed with additives during polymerization, but with additives mixed with each polymer after preparing the polymer.

First, the graft copolymer (A) is prepared by graft polymerization of 30 to 70% by weight of conjugated diene rubber, 20 to 40% by weight of aromatic vinyl compound, and 10 to 30% by weight of vinyl cyanide compound. If the amount of each component is out of the above range, the gloss and whiteness, which are mechanical properties and appearance characteristics, are lowered. In particular, when the amount of the vinyl cyanide compound is less than 10% by weight, there is a problem that the chemical resistance is lowered and the gloss is lowered. In this case, a general polymerization method such as emulsion polymerization, suspension polymerization, or bulk polymerization may be used, but preferably, emulsion polymerization method having excellent characteristics and mechanical properties is used. Here, styrene, alphamethylstyrene or vinyl toluene may be used as the aromatic vinyl compound, and acrylonitrile or methacrylonitrile may be used as the vinyl cyanide compound. The emulsifiers used in the graft polymerization are fatty acid alkali metal salts, fatty acid sulfate ester salts or disproportionated alkali metal salts, and can be used as long as they are emulsifiers usually used for emulsion polymerization of vinyl monomers. In addition, any polymerization initiator used in emulsion polymerization can be used without limitation, such as water-soluble or fat-soluble initiator. Water-soluble initiators include potassium persulfate or ammonium persulfate, and redox initiation such as organic hydroperoxide-iron salt. You can use the system. In addition, a small amount of mercaptans, terpenes, and halogen compounds may be used as the polymerization regulator. In addition, the conjugated diene-based rubber used in the present invention is butadiene, 1,3-pentadiene or isoprene, the distribution of rubber particle diameter dispersed in the graft polymer is 0.15 ~ 0.40 ㎛ particles in the total rubber particles 70 to 90% is preferable in terms of mechanical properties and glossiness. If the particle diameter is less than 70% having a particle size of 0.15 ~ 0.40 ㎛ excellent gloss characteristics, but there is a problem that the impact strength is lowered, if more than 90% there is a problem that the fluidity is lowered and the gloss is lowered. The graft copolymer (A) thus prepared contains 40 to 70% by weight of the total thermoplastic resin composition, but if the content is less than 40% by weight, there is a problem that the physical properties are lowered and productivity is degraded, and 70% by weight If exceeded, the surface glossiness is deteriorated and there is a problem in that the high temperature thermal stability is particularly low due to the deterioration of dispersibility.

The copolymer (b) is composed of 70 to 80% by weight of an aromatic vinyl compound and 20 to 30% by weight of a vinyl cyanide compound. The preparation method may be either an emulsion polymerization method or a bulk polymerization method. It's legal. The prepared copolymer should have a yellowness index of 10 or less, and preferably have a value of 6 or less. At this time, if the content of the vinyl cyanide compound is less than 20% by weight, the whiteness is improved, but glossiness or physical properties are lowered, and if it exceeds 30% by weight, the whiteness is sharply reduced. Here, the aromatic vinyl compound and the vinyl cyanide compound to be used are the same as in the preparation of the graft copolymer, the prepared copolymer contains 30 to 60% by weight of the total resin composition. If the content is less than 30% by weight, the impact strength is improved, but there is a problem in that the appearance characteristics, that is, gloss and whiteness are lowered, and when the content exceeds 60% by weight, physical properties such as impact strength are deteriorated.

In addition, in the present invention, 0.1 to 2.0 parts by weight of polyol is added to 100 parts by weight of the copolymer mixture of (a) and (b), wherein the polyol has 2 to 8 functional groups and is polyether polyol and polytetramethylene glycol. , Alkylene oxide glycol, polyester polyol, polycarbonate diol, acryl polyol and polybutadiene diol, and the like, and these may be used alone or in combination of two or more thereof. Although the molecular weights of these polyols are 200-10,000, it is preferable that they are 2000-4000. Here, the polyol has a refractive index different from that of the resin, which causes diffuse reflection of light to improve the whiteness of the appearance. If the addition amount is out of the above range, there is a problem that the resin vents during extrusion. In addition, an oxidative stabilizer is added in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the copolymer mixture of (a) and (b). Phosphorus oxidative stabilizer.

The graft polymer (A) prepared above is prepared in a powder state, and a copolymer (B), a polyol, and an oxide stabilizer are mixed and injected to prepare a thermoplastic resin.

The thermoplastic resin composition of the present invention as described above is a graft copolymer having a rubber particle size of the optimum physical properties compared to the conventional thermoplastic resin composition prepared using only small particle size rubber or the bulk polymerization method has a low impact strength and fluidity By using a copolymer prepared by the bulk polymerization method, the physical properties, glossiness and whiteness were greatly improved. In addition, the addition of polyols having different refractive indices caused diffused reflection of light to improve the whiteness of appearance, and to prevent discoloration of the resin composition by adding an oxidative stabilizer.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited by the Examples.

Preparation Example 1: Preparation of Graft Copolymer (A)

After replacing the inside of the reactor equipped with a stirrer with nitrogen, after adding 79 kg of pure water, 0.35 μm of average particle size, and 2.3 kg of polybutadiene latex with a particle size distribution of 0.15 ~ 0.40 μm and a solution of potassium disproportionate, the inside of the reactor was 65 Adjusted to. And the monomer mixture consisting of acrylonitrile and styrene and t-dodecyl mercaptan were added to the reactor over 3 hours. After the addition of the monomer mixture, the polymerization was continued for 3 hours at 88 ° C. As a result, the polymerization rate was 98%. Here, the amount of polybutadiene, styrene and acrylonitrile added is variable as shown in the following table.

Preparation Example 2: Preparation of Copolymer (B)

In the continuous bulk polymerization step, first, t-dodecyl mercaptan was continuously supplied to the first polymerization tank with acrylonitrile, styrene as a monomer, benzoyl peroxide as an initiator, and a molecular weight regulator. When the polymerization rate reached 35% at 130 ° C, the mixture was transferred to a second polymerization tank, where the temperature was raised to 200 ° C, and ethylbenzene was used as a viscosity reducing agent. When the polymerization rate reaches 70%, the residue is transferred to a devolatilization unit to recover residual monomers and viscosity reducing agents. At this time, the polymerization rate becomes 90%. At this time, the viscosity is adjusted by the addition amount of the pressure and the viscosity reducing agent. An oxidation stabilizer is added to the molten resin obtained here to obtain a copolymer through an extruder. Here, the addition amount of styrene and acrylonitrile is variable as shown in the following table.

[Examples 1 to 5 and Comparative Examples 1 to 3]

According to the method of Preparation Example 1, 5.0 parts by weight of electrolytic magnesium sulfate, a coagulant, was added to the graft copolymer radex prepared by varying the content of polybutadiene, styrene, and acrylonitrile, thereby solidifying, washing and Drying gave graft polymer powder. Graft copolymer (A) in the powder of the copolymer prepared by varying the content of styrene and acrylonitrile according to the method of Preparation Example 2 as shown in the following table (b), phenolic antioxidant and molecular weight is 3500 Polybutadiene polyols were added and mixed in a mixing ratio as shown in the following table.

It was then pelletized at 220 ° C. using a 40 ° extruder. Then, the ASTM test piece was molded with a 5 ounce molding machine to measure physical properties under ASTM test conditions, and the results are shown in the following table.

In addition, the pellet was molded into a color chip specimen size of 10 × 5 × 0.32 cm to obtain whiteness, yellowness and glossiness using color computer matching (ccm, product of ACS, model name: ACE 2013 system). It measured, and the result is as shown in the following table.

As shown in the table, it can be seen that the graft copolymer, the styrene-acrylonitrile copolymer, and the thermoplastic resin composed of a polyol and an oxidative stabilizer have excellent impact strength and high whiteness as shown in the present invention.

Claims (5)

(A) 40 to 70% by weight graft copolymer of conjugated diene rubber, aromatic vinyl compound and vinyl cyanide compound, (B) 30 to 60% by weight copolymer of aromatic vinyl compound and vinyl cyanide compound, (A) and ( B) 0.1 to 2.0 parts by weight of a polyol having a molecular weight of 2,000 to 4,000 and (d) 0.01 to 2.0 parts by weight of an antioxidant stabilizer, based on 100 parts by weight of the copolymer mixture of b). According to claim 1, wherein the graft copolymer (A) is 30 to 70% by weight of the conjugated diene rubber having a particle size distribution of 0.15 ~ 0.40 ㎛ 70 ~ 90%, 20 to 40% by weight aromatic vinyl compound and vinyl cyanide Thermoplastic resin composition, characterized in that consisting of 10 to 30% by weight of the compound. The thermoplastic resin composition according to claim 1, wherein the copolymer (b) is prepared by bulk polymerization of 70 to 80 wt% of an aromatic vinyl compound and 20 to 30 wt% of a vinyl cyanide compound. The method of claim 1, wherein the polyol is a thermoplastic, characterized in that the polyether polyol, polytetramethylene glycol, alkylene oxide glycol, polyester polyol, polycarbonate diol, acryl polyol, polybutadiene diol alone or a mixture of two or more thereof Resin composition. The thermoplastic resin composition of claim 1, wherein the oxidative stabilizer is a single or a mixture of two or more selected from a phenolic oxidative stabilizer, an amine oxidative stabilizer, a sulfur oxidative stabilizer, and a phosphorus oxidative stabilizer.