KR20140039546A - Polycarbonate resin composition having good scratch resistance and transparency - Google Patents

Abstract

Disclosed are a high hardness transparent polycarbonate resin composition having excellent surface hardness and optical properties without an additional secondary process by using a methacrylic copolymer resin which has specific properties to a high hardness transparency polycarbonate material and a molded article manufactured by using the same. The present invention provides a polycarbonate resin composition which comprises 50-90 wt% of a polycarbonate resin and 10-50 wt% of a methacrylic copolymer resin, and the methacrylic copolymer resin has weight-average molecular weight of not less than 2000 and not greater than 3000 and a product manufactured by using the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate resin composition having excellent scratch resistance and transparency,

The present invention relates to a polycarbonate resin composition, and more particularly, to a polycarbonate resin composition comprising a polycarbonate as a base resin and a high refractive index methacrylic copolymer.

Polycarbonate resin is excellent in impact resistance and mechanical properties, and exhibits high transparency, excellent dimensional stability, and broad coloring property. Recently, as a result of cost reduction, enlargement, and weight reduction of electric and electronic products, plastic products using polycarbonate resin The area of glass or metal material is rapidly replacing, and the range of use is expanded to electric and electronic products as well as automobile parts. As a result, functions and appearance performance as exterior materials have become more important than existing materials, and the performance of scratches caused by external impacts has been increasing.

In general, in order to improve the scratch resistance of plastics, a surface of a final molded resin is coated with an organic-inorganic hybrid material and subjected to chemical treatment such as UV curing or thermosetting, or physical treatment such as plasma assisted deposition . However, if the secondary process is carried out, the cost of the additional process increases, the process time becomes longer, and environmental pollution occurs due to secondary treatment. Therefore, in recent years, there has been an increasing demand for unpainted resins capable of exhibiting scratch resistance without hard coating. In the case of blending polymers having a high scratch resistance of plastics, it is necessary to use a polycarbonate unique There is a problem in that the transparency of the film is easily lost and the surface quality is deteriorated.

To solve such a problem, a resin composition in which a polycarbonate resin and a methacrylic resin are mixed is disclosed. As described above, in the case of a polycarbonate resin having excellent physical properties, since the scratch resistance is not as good as the pencil hardness of 2B, the methacrylic resin having excellent scratch resistance with pencil hardness of 3H to 4H is mixed and used. However, Problems arise.

US Patent Publication No. 2012-0121845 has attempted to improve the surface hardness by applying silicon dioxide nanoparticles to a polycarbonate substrate. However, due to the secondary processing for the coating, process cost is increased, process time is long, .

U.S. Patent No. 8,088,849 discloses a technique using an ether phosphoric acid compound and a halogen compound to maintain the surface hardness, flame retardancy, and transparency of a polycarbonate substrate. However, when a halogen compound is used, .

Korean Patent Laid-Open No. 2009-0039612 attempts to improve the scratch resistance by using a methacrylic copolymer resin composition, but it has a problem of high haze and low transparency.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a high hardness transparent polycarbonate material having a high hardness and transparency A polycarbonate resin composition and a molded article produced using the same.

In order to solve the above-described problems, the present invention provides a resin composition comprising 50 to 90% by weight of a polycarbonate resin; And 10 to 50% by weight of a methacrylic copolymer resin, wherein the methacrylic copolymer resin has a weight average molecular weight of 2,000 or more and less than 3,000.

In addition, the methacrylic copolymer resin has a refractive index of 1.52 to 1.58.

Also, the methacrylic copolymer resin is a copolymer of 10 to 100% by weight of an aliphatic or aromatic methacrylate represented by the following formula (1) and 0 to 90% by weight of a monofunctional unsaturated monomer: do.

[Chemical Formula 1]

(Wherein m is an integer of 0 to 10, and X is a methyl group, a phenyl group, a cyclohexyl group, a methylphenyl group, a methylethylphenyl group, a propylphenyl group, a methoxyphenyl group, a cyclohexylphenyl group, a chlorophenyl group, Or a benzylphenyl group)

The haze of the specimen obtained by extruding the polycarbonate resin and the methacrylic copolymer at a weight ratio of 7: 3 and having a thickness of 3.0 mm according to the ASTM evaluation method D1003 was 0.8% or less, and according to ASTM evaluation method D1003 And a transmittance (TT) of 90% or more.

In order to solve the above-mentioned problems, the present invention provides a product manufactured using the polycarbonate resin composition.

According to the present invention, a methacrylic copolymer resin having a relatively low weight average molecular weight in a polycarbonate resin is melt-extruded from a composition mixed in an optimal range, whereby the methacrylic copolymer imparts excellent moldability A polycarbonate resin composition having improved scratch resistance while maintaining transparency inherent to polycarbonate, and a product using the polycarbonate resin composition can be provided.

Further, by using a methacrylic copolymer having a high refractive index, the phase separation with the polycarbonate is minimized to further prevent the transparency from deteriorating and maintain a good appearance, and also it is possible to operate in the same process facility as the polycarbonate molding, Significant savings can be achieved.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present inventors have found that the transparency of the resin composition is rather reduced due to the methacrylic copolymer resin mixed for improving the scratch resistance of the polycarbonate resin, and the methacrylic copolymer resin having a specific weight average molecular weight and refractive index It is possible to improve the scratch resistance and to dramatically improve the transparency as compared with the conventional resin composition, leading to the present invention.

Accordingly, the present invention provides a resin composition comprising 50 to 90% by weight of a polycarbonate resin; And 10 to 50% by weight of a methacrylic copolymer resin, wherein the methacrylic copolymer resin has a weight average molecular weight of 2,000 or more and less than 3,000. First, components constituting the resin composition according to the present invention will be described in detail.

Polycarbonate resin

The polycarbonate (PC) resin used in the present invention is an amorphous polymer having excellent transparency, excellent impact resistance, self-extinguishing ability, flexibility and processability, excellent weather resistance, long-term high physical properties, excellent heat resistance and cold resistance, Performance can be maintained even with temperature changes.

The polycarbonate resin may be prepared by a conventional method, for example, by reacting a dihydroxy phenol compound with a phosgene in the presence of a molecular weight modifier and a catalyst, or by reacting dihydroxy Can be prepared using an ester interchange reaction of a phenol compound and a precursor obtained by diphenyl carbonate.

Here, as the dihydroxyphenol compound, a bisphenol compound may be used, and bisphenol A (2,2-bis (4-hydroxyphenyl) propane) may be preferably used. At this time, the bisphenol A may be partially or wholly replaced with another kind of dihydroxy phenolic compound. (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis Bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfone, bis Bis (4-hydroxyphenyl) ether, 2,2, -bis (3,5-dibromo-4-hydroxyphenyl) propane and the like.

The polycarbonate resin may be a homopolymer of a dihydroxy phenolic compound, a copolymer of two or more dihydroxy phenolic compounds, or a mixture thereof.

In general, the polycarbonate resin may have the form of a linear polycarbonate resin, a branched polycarbonate resin, a polyester carbonate copolymer resin or the like. As the polycarbonate resin contained in the polycarbonate resin composition used in the present invention, But the linear polycarbonate resin, the branched polycarbonate resin, or the polyester carbonate copolymer resin and the like can be used. As the linear polycarbonate resin, for example, a bisphenol A-based polycarbonate resin may be used. As the branched polycarbonate resin, for example, a polyfunctional aromatic compound such as trimellitic anhydride or trimellitic acid With a dihydroxyphenol compound and a carbonate precursor can be used. As the polyester carbonate copolymer resin, for example, a bifunctional carboxylic acid can be prepared by reacting a dihydroxyphenol compound and a carbonate precursor, May be used.

In the present invention, the polycarbonate resin is used in an amount of 50 to 90% by weight, preferably 50 to 80% by weight, more preferably 50 to 70% by weight, and most preferably 50 to 60% by weight based on the total weight of the polycarbonate resin composition % ≪ / RTI > by weight. If the content of the polycarbonate resin is less than 50% by weight, excellent mechanical properties of the polycarbonate may not be exhibited. If the content of the polycarbonate resin exceeds 90% by weight, improvement in scratch resistance may not be expected.

In the present invention, the polycarbonate resin may have a weight average molecular weight of 10,000 to 200,000, preferably 15,000 to 80,000, and more preferably 20,000 to 50,000.

Methacrylic system  Copolymer resin

The methacrylic copolymer resin used in the present invention has a weight average molecular weight of from 2,000 or more to less than 3,000 and is excellent in compatibility with the polycarbonate resin in the weight average molecular weight range, And a polycarbonate resin composition having particularly excellent properties in terms of fogging property and transparency can be obtained. Further, by using a methacrylic copolymer resin having a high refractive index of 1.52 to 1.58, the haze in the blended molding product with the polycarbonate resin can be maintained to a high transparency of 0.8% or less which is equivalent to that of the polycarbonate. Here, the methacrylic copolymer resin having a high refractive index is a resin modified with an aromatic or aliphatic methacrylate, and can be polymerized by conventional bulk, emulsion and suspension polymerization methods.

In the present invention, the methacrylic copolymer resin may be a copolymer of 10 to 100% by weight of aromatic or aliphatic methacrylate and 0 to 90% by weight of monofunctional unsaturated monomer. When the aromatic or aliphatic methacrylate is less than 10% by weight, the average refractive index of the polymerized methacrylic copolymer resin may be less than 1.52. The methacrylic copolymer may be represented by the following general formula (1).

[Chemical Formula 1]

(Wherein m is an integer of 0 to 10, and X is a methyl group, a phenyl group, a cyclohexyl group, a methylphenyl group, a methylethylphenyl group, a propylphenyl group, a methoxyphenyl group, a cyclohexylphenyl group, a chlorophenyl group, Or a benzylphenyl group)

The aromatic or aliphatic methacrylate includes, for example, cyclohexyl methacrylate, 2-ethylphenoxy methacrylate, 2-ethylthio phenyl methacrylate, phenyl methacrylate, Ethylmethacrylate, 3-phenylpropylmethacrylate, 4-phenylbutylmethacrylate, 2,2-methylphenylethylmethacrylate, 2,3-methylphenylethylmethacrylate, 2,4-methylphenylethylmethacrylate Ethyl methacrylate, 2- (4-methylphenyl) ethyl methacrylate, 2- (4-methoxyphenyl) 2- (3-chlorophenyl) ethyl methacrylate, 2- (4-chlorophenyl) ethyl methacrylate, 2- 2- (4-bromophenyl) ethyl methacrylate, 2- (3-phenylphenyl) ethyl methacrylate, 2- There may be mentioned acrylate and the like.

Examples of the monofunctional unsaturated monomer include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, benzyl methacrylate and the like, acrylates such as methyl acrylate, ethyl Unsaturated carboxylic acids such as acrylic acid and methacrylic acid, acid anhydrides such as maleic anhydride and the like, acid anhydrides such as 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, Acrylate, methacrylamide, acrylonitrile, methacrylonitrile, allyl glycidyl ether, glycidyl methacrylate, styrene, acrylonitrile, methacrylonitrile, methacrylonitrile, Alpha methyl styrene, and the like.

In the present invention, the methacrylic copolymer resin is used in an amount of 10 to 50% by weight, preferably 20 to 50% by weight, more preferably 30 to 50% by weight, and most preferably 30 to 50% by weight based on the total weight of the polycarbonate resin composition 40 to 50% by weight. If the content of the methacrylic copolymer resin is less than 10% by weight, improvement in scratch resistance may not be expected. If it exceeds 50% by weight, a flow mark may be formed during molding.

The resin composition according to the present invention may further contain another additive depending on the purpose of use within the scope of the present invention. As additional additives, additives such as a flame retardant, a surfactant, a nucleating agent, a coupling agent, an impact modifier, a heat stabilizer, a releasing agent, an inorganic additive, a UV stabilizer, a dye, a pigment, a compatibilizer, a colorant, a lubricant, Or two or more of them may be further added and may be added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the resin composition.

The resin composition according to the present invention can be prepared by a known method. For example, the polycarbonate resin and the methacrylic copolymer resin may be mixed with other additives at the same time and then melt-extruded in an extruder to produce pellets, and various plastic injection and extrusion molded articles can be manufactured using the pellets . The melt extrusion may be carried out at a screw rotation speed of 50 to 1000 rpm for a retention time of 5 to 90 seconds, preferably at a screw rotation speed of 200 to 800 rpm for a retention time of 10 to 60 seconds. The residence time is preferably 90 seconds or less in order to prevent deterioration of the methacrylic copolymer resin and to improve productivity.

The polycarbonate resin composition prepared according to the present invention was prepared by mixing the polycarbonate resin and the methacrylic copolymer at a weight ratio of 7: 3 and extruding the mixture to a thickness of 3.0 mm. The haze according to ASTM evaluation method D1003 was 0.8 Or less, and a transmittance (TT) of 90% or more according to ASTM Evaluation Method D1003.

Hereinafter, a specific embodiment of the present invention will be described.

Example  One

(H-880, manufactured by Mitsubishi Rayon Co., Ltd.) having a weight-average molecular weight of 2,500 and a refractive index of 1.54 to 1.56 and a 10 wt% A polycarbonate resin composition was produced in a pellet form under extrusion conditions of an extrusion temperature of 270 to 300 ° C and a screw rotation speed of 200 rpm using a twin screw extruder (screw diameter 26 mm, L / D = 40) After drying at 80 ° C for 5 hours, the specimen was molded using a mold for specimen preparation.

Example  2

A specimen was formed in the same manner as in Example 1, except that the polycarbonate resin and the methacrylic copolymer resin were mixed at a ratio of 80 wt% and 20 wt%, respectively.

Example  3

A specimen was formed in the same manner as in Example 1 except that the polycarbonate resin and the methacrylic copolymer resin were mixed at a ratio of 70% by weight and 30% by weight, respectively.

Example  4

A specimen was formed in the same manner as in Example 1 except that the polycarbonate resin was mixed at a ratio of 60 wt% of the polycarbonate resin and 40 wt% of the methacrylic copolymer resin in Example 1.

Example  5

A specimen was formed in the same manner as in Example 1, except that the polycarbonate resin and the methacrylic copolymer resin were mixed at a ratio of 50 wt% and 50 wt%, respectively.

Comparative Example  One

A specimen was formed in the same manner as in Example 1, except that the methacrylic copolymer resin was not mixed in Example 1 but made of 100 wt% of polycarbonate resin.

Comparative Example  2

A specimen was formed in the same manner as in Example 2, except that a methacrylic copolymer resin having a weight average molecular weight of 3,500 was used in Example 2.

Comparative Example  3

A specimen was formed in the same manner as in Example 2, except that a methacrylic copolymer resin having a weight average molecular weight of 5,500 was used in Example 2.

Comparative Example  4

A specimen was formed in the same manner as in Example 2 except that a methacrylic copolymer resin having a weight average molecular weight of 8,500 was used in Example 2.

The composition of the resin compositions prepared according to the above Examples and Comparative Examples is shown in Table 1 below.

Test Example

In order to evaluate the physical properties, optical characteristics and scratch resistance of the resin composition according to the present invention, the specimens prepared according to the above Examples and Comparative Examples were measured according to the following methods, and the results are shown in Table 2 below.

[How to measure]

(1) glass transition temperature

ASTM evaluation method D3418.

(2) melt index

And measured according to ASTM Evaluation Method D1238.

(3) Cloudiness

ASTM evaluation method D1003.

(4) Transmittance

ASTM evaluation method D1003.

(5) Scratch resistance

It was measured according to ASTM Evaluation Method D3363.

Referring to Table 2, first, in the case of the test piece made of the resin composition using the methacrylic copolymer resin having the component composition range and the weight average molecular weight range according to the present invention, the change in haze was within 0.2% It can be seen that the scratch resistance is improved in a highly transparent state in which there is little change.

On the other hand, in the case of the test piece (Comparative Example 1) made only of a pure polycarbonate resin without using the methacrylic copolymer resin according to the present invention, the scratch resistance was not good, and in order to improve the scratch resistance, In the case where the weight average molecular weight exceeds a certain range (Comparative Examples 2 to 4), even when the cohesive resin is used, the haze and the transmittance are significantly different from the case of using the methacrylic copolymer resin having the weight average molecular weight according to the present invention , Respectively.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (5)

50 to 90% by weight of polycarbonate resin; And 10-50 wt% of methacrylic copolymer resin; wherein the methacrylic copolymer resin has a weight average molecular weight of 2,000 or more and less than 3,000. The method of claim 1,
Wherein the methacrylic copolymer resin has a refractive index of 1.52 to 1.58. 3. The method according to claim 1 or 2,
Wherein the methacrylic copolymer resin is a copolymer of 10 to 100% by weight of an aliphatic or aromatic methacrylate represented by the following formula (1) and 0 to 90% by weight of a monofunctional unsaturated monomer.
[Chemical Formula 1]

(Wherein m is an integer of 0 to 10, and X is a methyl group, a phenyl group, a cyclohexyl group, a methylphenyl group, a methylethylphenyl group, a propylphenyl group, a methoxyphenyl group, a cyclohexylphenyl group, a chlorophenyl group, Or a benzylphenyl group) 3. The method according to claim 1 or 2,
The haze of the specimen obtained by extruding the polycarbonate resin and the methacrylic copolymer at a weight ratio of 7: 3 by weight and extruding the specimen to a thickness of 3.0 mm was 0.8% or less according to ASTM Evaluation Method D1003, and the transmittance according to ASTM Evaluation Method D1003 TT) of the polycarbonate resin composition is 90% or more. A product produced by using the polycarbonate resin composition of any one of claims 1 to 3.