KR20110073243A - Thermoplastic resin composition having good scratch resistance and molded article made therefrom - Google Patents

Abstract

PURPOSE: A thermoplastic resin composition is provided to ensure a good balance of various properties such as scratch resistance, impact strength, colorability, gloss, and injection molding properties. CONSTITUTION: A thermoplastic resin composition with scratch resistance comprises: (A) 10-20% by weight of a rubber modified aromatic vinyl graft copolymer resin; (B) 30-50% by weight of polymethylmethacrylate (PMMA) resin; and (C) 40-60% by weight of an aromatic vinyl copolymer resin including about 5 to about 50% by weight of a (meth)acrylate alkyl ester.

Description

Thermoplastic resin composition having good scratch resistance and molded article made therefrom}

The present invention relates to a thermoplastic resin composition having excellent scratch resistance and a molded article manufactured therefrom, and more particularly to a thermoplastic resin composition having excellent physical balance such as impact strength, colorability, glossiness, scratch resistance, and the like and a molded article produced therefrom. It is about.

In general, acrylonitrile-butadiene-based rubber-styrene (ABS) resins have excellent impact resistance and workability, and have good mechanical strength, heat deformation temperature, and glossiness, and thus are widely used in electrical and electronic parts and office equipment. However, ABS resins used in high-end housings such as LCD, PDP TV, audio, etc., are prone to scratches during injection molding or use, and have difficulty in expressing color of high-quality textures.

In order to solve this problem, the surface of the ABS injection molded product has been coated with urethane, UV coating treatment or acrylic resin having excellent scratch characteristics. However, such work is accompanied by the problem of productivity degradation such as the complexity of the work and the increase of the defective rate by the addition of additional post-processing process and the environmental pollution problem due to the painting. Therefore, there is an urgent need for the development of new resins that can improve gloss and impact resistance, facilitate injection molding operations, and improve the scratch characteristics generated during use.

Usually, as the scratch-resistant material which does not apply urethane coating, PMMA resin, acrylic resin, etc. which are excellent in colorability and glossiness are used. However, since PMMA resin is weak in impact resistance and not easy to form, it is difficult to manufacture a molded product through injection. Therefore, a method of attaching the sheet to the surface of a molded product after fabricating an extruded sheet is used. There are disadvantages such as excessive production cost.

In addition to the PMMA resin, methyl methacrylate-acrylonitrile-butadiene-styrene resin may be used as the scratch material, in which case the colorability, gloss, shock resistance, and impact resistance of the present invention are good, but R is an important physical property for scratch properties. -The hardness and the flexural modulus (Modulus) is weak, there is a problem that the curvature decreases and the bending due to the lack of strength during molding.

In addition, the ABS / PMMA alloy has the advantages of impact resistance of the ABS resin, but the colorability is poor and scratch resistance is not good.

An object of the present invention is to provide a thermoplastic resin composition having excellent balance of physical properties such as scratch resistance, impact strength, colorability, glossiness, and the like and high injection molding properties.

Another object of the present invention is to provide a molded article prepared from a thermoplastic resin composition having excellent balance of physical properties such as scratch resistance, impact strength, colorability, glossiness, and the like and having high injection molding properties.

The above and other objects of the present invention can be achieved by the present invention described in detail.

In order to achieve the above technical problem, the present invention (A) rubber modified styrene-based graft copolymer resin 10 to 20% by weight; (B) 30 to 50% by weight of polymethyl methacrylate (PMMA) resin; And (C) 40 to 60% by weight of the styrene-based copolymer resin containing 5 to 50% by weight of the (meth) acrylic acid alkyl ester component; provides excellent scratch resistance thermoplastic resin composition comprising a.

The (A) rubber-modified styrenic graft copolymer resin is specifically, 10 to 60% by weight of a rubbery polymer, 20 to 80% by weight of an aromatic vinyl monomer, and 5 to 45 monomers copolymerizable with the aromatic vinyl monomer. It may consist of weight percent.

The styrene-based copolymer resin containing 5 to 50% by weight of the (C) (meth) acrylic acid alkyl ester component may specifically include methyl methacrylate-acrylonitrile-styrene (MSAN) resin.

The thermoplastic resin composition may further include an additive selected from the group consisting of antioxidants, lubricants, impact modifiers, light stabilizers, dyes, pigments, flame retardants, fillers, stabilizers, lubricants, antibacterial agents, mold release agents, plasticizers, and antistatic agents.

In order to achieve the above another technical problem, the present invention provides a molded article prepared according to the thermoplastic resin composition excellent in scratch resistance of the present invention.

The thermoplastic resin composition of the present invention has excellent balance of physical properties such as scratch resistance, impact strength, colorability, glossiness, and the like, and excellent injection molding.

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

(A) Core-shell type rubber modified styrene graft copolymer resin

The core-shell type rubber-modified styrene graft copolymer resin (A) is a graft copolymer of a rubbery polymer, an aromatic vinyl monomer, a monomer copolymerizable with an aromatic vinyl monomer, and a monomer that selectively provides workability and heat resistance. Get it done.

Examples of the rubbery polymer include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene), and acrylic rubbers such as saturated rubbers, isoprene rubbers and polybutylacrylic acid hydrogenated with the diene rubbers. Rubber and ethylene-propylene-diene monomer terpolymer (EPDM); Among these, especially diene rubber is preferable and butadiene rubber is more preferable.

The aromatic vinyl monomer in the graft copolymerizable monomer mixture may include styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, para t-butylstyrene, ethyl styrene, vinyl xylene, monochlorostyrene, dichlorostyrene, Dibromostyrene, vinyl naphthalene, or the like may be used, but is not necessarily limited thereto. Of these, styrene is most preferred.

The rubber-modified styrene graft copolymer resin may be introduced at least one monomer copolymerizable with an aromatic vinyl monomer. As the monomer to be introduced, vinyl cyanide such as acrylonitrile and unsaturated nitrile based compounds such as ethacrylonitrile and methacrylonitrile are preferable, and may be used alone or in combination of two or more thereof.

Examples of the monomer for imparting the processability and heat resistance include acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide.

The method for producing the core-shell type rubber-modified styrene graft copolymer resin will be described as an example. (I) Rubber polymer latex 50- having an average particle diameter of 0.28 to 0.35 µm and a gel content of 75 to 85%. In the 70 parts by weight of 10 to 40% by weight of 50 to 30 parts by weight of the graft monomer mixture consisting of 65 to 85% styrene and 35 to 15% acrylonitrile was added to the reactor, the molecular weight regulator, reducing agent, emulsifier, polymerization initiator and A first step of preparing a first graft copolymer latex so that the reactor is heated while stirring and adding ion-exchanged water, and then a catalyst mixture is added so that the polymerization conversion rate is 90-96%; (2) 90-60% of the remaining graft monomer mixture (B) and the molecular weight regulator are mixed with the first graft copolymer latex, and the second graft air is continuously added for 2 to 5 hours simultaneously with the polymerization initiator. A second step of preparing the coalescing latex, each of which is described in detail in Korean Patent Publication No. 2003-0056087, the contents of which are incorporated herein in its entirety.

(B) polymethyl methacrylate resin

The polymethyl methacrylate resin (B) is obtained by polymerizing methyl methacrylate (MMA), an acrylic resin, which is well known to those skilled in the art and can be easily purchased commercially. .

In the present invention, by adding a polymethyl methacrylate resin (PMMA), it is possible to have a scratch resistance excellent in pencil hardness.

The PMMA resin is included in 30 to 50% by weight. When used in excess of 50% by weight, the impact strength may be lowered, and when used in less than 30% by weight 충분한 not enough scratch resistance properties.

If the manufacturing method of the polymethyl methacrylate resin is described as an example, the reactor is heated while stirring and stirring the deionized water, the crosslinking agent, the emulsifier, the initiator, the methyl methacrylate monomer, and the methacrylate acid, and then the catalyst mixture is added. Polymerize.

(C) Styrene-based copolymer resin containing 5 to 50% by weight of (meth) acrylic acid alkyl ester component

The styrenic copolymer resin (C) containing 5 to 50% by weight of the (meth) acrylic acid alkyl ester component is prepared by copolymerizing a (meth) acrylic acid alkyl ester compound, an aromatic vinyl compound and a vinyl cyanide compound. At this time, the (meth) acrylic acid alkyl ester compound is preferably 5 to 50% by weight, 30 to 80% by weight of the aromatic vinyl compound and 10 to 40% by weight of the vinyl cyanide compound. More preferably, the (meth) acrylic acid alkyl ester compound may be used in an amount of # 10 to 30% by weight, most preferably 15 to 20% by weight. The prepared transparent resin molecular weight is characterized by having a weight average molecular weight of about 100,000 to 200,000, and more preferably a weight average molecular weight of about 120,000 to 160,000.

In addition to the above components, the thermoplastic resin composition having excellent scratch resistance of the present invention is usually an antioxidant, a lubricant, an impact modifier, a light stabilizer, a dye, a pigment, a flame retardant, a filler, a stabilizer, a lubricant, an antibacterial agent, a mold release agent, a plasticizer, an antistatic agent, and the like. It may further include an additive. As the antioxidant, a hindered phenol-based antioxidant or a phosphite-based antioxidant may be used. As the lubricant, a steramid lubricant or a metal stearate lubricant may be preferably used.

The thermoplastic resin composition having excellent scratch resistance of the present invention is relatively excellent in injection moldability compared to the existing scratch-resistant resin using g-ABS, it is possible to increase the Izod impact strength. In addition, as the scratch resin, physical property balance such as colorability, glossiness, scratch resistance and the like is good.

The thermoplastic resin composition having excellent scratch resistance of the present invention may also have good physical balance without undergoing post-processing processes such as UV coating and acrylic resin film attachment process.

The resin composition of the present invention may be manufactured by injection molding through the usual melt kneading process by adding the above components.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

The components used in the Examples and Comparative Examples of the present invention are as follows.

(A) Core-shell type rubber modified styrene graft copolymer resin

Core-shell type g-ABS air with an average particle diameter of 300 μm prepared by an emulsion graft polymerization method comprising 58 parts by weight of polybutadiene rubber latex having an average particle diameter of 0.3 μm, 35 parts by weight of acrylonitrile, and 65 parts by weight of styrene. Copolymer resin was used.

(B) polymethyl methacrylate resin

PMMA having a weight average molecular weight (Mw) of 85,000 containing 88 parts by weight of methyl methacrylate monomer and 12 parts by weight of methacryl acid as a comonomer was used.

(C) Styrene copolymer resin containing (meth) acrylic acid alkyl ester component

M-SAN copolymer resin having a weight average molecular weight (Mw) of 200,000 parts by weight of methyl methacrylate monomer, 20 parts by weight of acrylonitrile monomer, and 70 parts by weight of styrene monomer was used.

(D) MS resin

(d1) A methyl methacrylate-styrene resin (MS-300) having a methyl methacrylate content of 30% by weight manufactured by Nippon Steel Corporation was used.

(d2) A methyl methacrylate-styrene resin (MS-320XL) having a methyl methacrylate content of 20% by weight manufactured by Nippon Steel Corporation was used.

Example  One

11 wt% prepared graft ABS prepared as described above, 35 wt% PMMA, and 54 wt% MSAN, 0.3 parts by weight of Irganox 1076 (Ciba) as an antioxidant, 0.4 g of ethylene bis-stearamid antioxidant as a lubricant 0.3 parts by weight of magnesium stearate and 0.3 parts by weight of carbon black were used as a weight part and a stabilizer to prepare pellets using a twin screw extruder, and a test piece for measuring physical properties using a injection machine, a thickness of 2.2 mm, a width of 10 mm, and a length of 6 mm. A specimen for measuring the colorability of was prepared.

Example  2 to 4 and Comparative Example  1 to 3

A specimen was prepared in the same manner as in Example 1, except that the composition and content of Table 1 were used.

The physical properties of each of the specimens for measuring the physical properties prepared in Examples and Comparative Examples were evaluated by the following method, and the evaluation results are shown in Table 2.

(1) Notched Izod Impact Strength: Measured based on ASTM D-256 (1/8 inch, kgf · cm / cm).

(2) Fluidity: The fluidity of 10 kg of the specimen at 220 ° C. was measured (g / 10 min) based on ISO1103.

(3) R-hardness: measured on the basis of ASTM D785 conditions.

(4) Flexural modulus and tensile strength: The flexural modulus was measured under ASTM D790 condition (kgf / cm2) and the tensile strength was based on ASTM D638 condition (kgf / cm2).

(5) Pencil hardness: After preparing a specimen with a thickness of 3mm, a length of 10mm, and a width of 10mm at 500 ° C at 23 ° C based on JIS K5401, the degree of scratching was visually determined by applying five times to the surface of the specimen. At the time of occurrence of abnormality, pencil hardness grades of 4B to 7H were determined.

(6) Colorability: L value and b value were measured and evaluated using a color difference machine. In this case, when the L value is in the negative direction, the saturation is increased, and the b value is the color direction of yellow and blue, and in general, the negative direction (blue direction) means the color is better. do.

(7) Glossiness: Measured based on ASTM D523 conditions.

As shown in Table 2, Comparative Example 1 using PMMA is excellent in scratch properties such as pencil hardness and R-hardness, glossiness, colorability, etc., but it is difficult to be applied in actual application due to weak impact resistance and injection resistance. In addition, Comparative Examples 2 and 3 using the MS resin containing methyl methacrylate content of 40% or less, but the impact resistance was secured, but it was difficult to secure scratch resistance such as R-hardness and pencil hardness, and it was confirmed that the colorability was reduced. .

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications are considered to be included within the scope of the present invention.

Claims (9)

(A) 10 to 20% by weight of the rubber-modified styrene graft copolymer resin; (B) 30 to 50% by weight of polymethyl methacrylate (PMMA) resin; And (C) 40 to 60% by weight of a styrene copolymer resin containing 5 to 50% by weight of the (meth) acrylic acid alkyl ester component. The thermoplastic resin composition having excellent scratch resistance.
According to claim 1, wherein the (A) rubber-modified styrenic graft copolymer resin is 10 to 60% by weight rubber-like polymer, 20 to 80% by weight aromatic vinyl monomer, and monomer 5 copolymerizable with the aromatic vinyl monomer The thermoplastic resin composition excellent in the scratch resistance characterized by consisting of -45 weight%.
The rubber polymer according to claim 2, wherein the rubber polymer is a diene rubber, a saturated rubber obtained by adding hydrogen to the diene rubber, isoprene rubber, chloroprene rubber, acrylic rubber, ethylene / propylene / diene monomer terpolymer (EPDM), and A thermoplastic resin composition excellent in scratch resistance, selected from the group consisting of two or more mixtures thereof.
3. The thermoplastic resin composition having excellent scratch resistance according to claim 2, wherein the aromatic vinyl monomer is selected from the group consisting of styrene, α-methylstyrene, nuclear substituted styrene, and a mixture of two or more thereof.
The monomer copolymerizable with the aromatic vinyl monomer is selected from the group consisting of acrylonitrile, methyl methacrylonitrile, methyl methacrylate, N-substituted maleimide, maleic anhydride, and mixtures of two or more thereof. The thermoplastic resin composition excellent in scratch resistance characterized by being selected.
According to claim 1, wherein the (C) styrene-based copolymer resin containing 5 to 50% by weight of the (meth) acrylic acid alkyl ester component is 5 to 50% by weight of the (meth) acrylic acid alkyl ester compound; 30 to 80% by weight aromatic vinyl compound; And 10 to 40% by weight of a vinyl cyanide compound, excellent scratch resistance thermoplastic resin composition.
The styrene-based copolymer resin containing the (C) (meth) acrylic acid alkyl ester component is excellent scratch resistance, characterized in that it comprises 10 to 30% by weight of the (meth) acrylic acid alkyl ester component. Thermoplastic resin composition.
The method of claim 1, wherein the thermoplastic resin composition comprises an additive selected from the group consisting of antioxidants, lubricants, impact modifiers, light stabilizers, dyes, pigments, flame retardants, fillers, stabilizers, lubricants, antibacterial agents, mold release agents, plasticizers, and antistatic agents. It further comprises a thermoplastic resin composition excellent in scratch resistance.
The molded article manufactured from the thermoplastic resin composition excellent in the scratch resistance of any one of Claims 1-8.