KR20090084574A - Transparent thermoplastic resin with high gloss and hardness - Google Patents

Abstract

A thermoplastic resin composition is provided to ensure excellent transparency, black colorability, gloss, hardness, impact strength, processability and scratch resistance, and to be used in appliance housings, especially, TV front and rear panel, etc. A transparent thermoplastic resin composition comprises 1-30 weight% of graft copolymer which graft-polymerizes methacrylic acid ester compound or acrylic acid ester compound, aromatic vinyl compound, and vinyl cyanide compound to a butadiene-based rubber; 10-50 weight% of aromatic vinyl compound-vinyl cyanide copolymer; and 20-70 weight% of polymethylmethacrylate resin. The flow index of the polymethylmethacrylate at 230‹C/3.8kg is 8 - 18.

Description

High gloss, high hardness transparent thermoplastic resin composition {Transparent Thermoplastic Resin with High Gloss and Hardness}

The present invention relates to a high gloss, high hardness transparent thermoplastic resin composition, more specifically butadiene-based graft copolymer; Aromatic vinyl compound-vinyl cyan compound copolymer; And it relates to a transparent thermoplastic resin composition consisting of polymethyl methacrylate resin.

Resins mainly used for products requiring transparency include SAN, PC, GPPS, MS, PMMA, and transparent ABS resins. Among these, the transparent resin having impact properties has transparency because the continuous phase matches the refractive index of the matrix resin with the refractive index of the rubber which is the dispersed phase, thereby minimizing scattering and refraction of light generated at the interface between the dispersed phase and the continuous phase.

Until now, U.S. Patent No. 3,787,522 and Japanese Patent Laid-Open No. 63-42940 disclose a method of imparting impact resistance to a transparent PMMA resin as a technique for producing a transparent resin having excellent transparency and physical properties. It was excellent but the impact resistance was extremely weak, there was a problem in the application limitations. In addition, European Patent No. 0,702,322 discloses a method of imparting transparency to HIPS resin, but this has a problem of lowering chemical resistance and scratch resistance. On the other hand, many studies on the transparent ABS resin having a relatively high chemical resistance and scratch resistance has been progressed, but there is a problem that most of the pencil hardness stays at the level of 2B or 3B.

On the other hand, polymethyl methacrylate resin is a resin that is excellent in transparency as an amorphous resin, commonly referred to as 'acrylic resin', and researched and developed in 1930 and industrialization began. It is the kind of resin that has the oldest history among the existing resins, and is the most transparent and has good weather resistance. Therefore, it is widely used for organic glass, electric parts and building materials.

In addition, acrylonitrile-styrene copolymer has excellent molding processability, transparency, rigidity and chemical resistance by controlling the content of components and molecular weight, and is blended with a product requiring stiffness and transparency or graft ABS plastic resin and chemically resistant. And it is used a lot in the form of processability improvement.

When appropriately kneading and molding the resins having various properties as described above, blend resins of various compositions have been introduced because each of them can give new properties that each resin cannot provide while maintaining the advantages of the components. . However, simple kneading alone does not exhibit new synergistic effects due to poor impact and transparency between ingredients, and only simple mixing properties or rather low properties. Therefore, a method of supplementing the properties of kneading products by adding new ingredients is studied. It is becoming.

In order to supplement the weak impact resistance of PMMA resin, research has been conducted to introduce an elastomer rubber having excellent impact resistance to PMMA. In general, when the rubber is introduced into the PMMA resin, the impact resistance may be improved to a satisfactory level, but a problem of deterioration of transparency, which is the biggest advantage of the PMMA, occurs.

Japanese Patent Publication No. 46-11035, US Patent Registration No. 4,287,315, US Patent Registration No. 3,646,164, Progress in Colloid Polymer Science 90: 227-231 (1992) and Italian Patent Registration No. 47,946 A8 In No. 9, impact-resistant PMMA was prepared using elastomer rubber to impart impact resistance to PMMA. However, the PMMA produced by the conventional method is greatly improved in terms of impact resistance, but has a disadvantage in that it is very inferior in transparency.

In the case of using an elastomer rubber, it is generally known that transparency remains due to the size of the dispersed phase and the difference in refractive index between the dispersed phase and the continuous phase resin. That is, if the size of the dispersed phase resin is much smaller than the wavelength of visible light, light scattering hardly occurs even if the refractive index does not coincide with that of the resin, and transparency is maintained. Even when large, transparency is maintained.

However, it is not easy to uniformly disperse the rubber particles having a size such that light scattering, which is generally known to have a diameter of 100 nm or less, in the PMMA resin is not easy, and thus the degree of impact resistance improvement is insignificant. It has been described in US Patent No. 5,338,804 that the impact resistance is hardly improved when using particles having a diameter of 100 nm or less, and the improvement is very small even if the impact resistance is improved.

In addition, since PMMA resins that form continuous phases are mixed with other acrylate monomers or additives to improve thermal stability, the refractive indices vary slightly depending on the type of product. It is also not easy to make. In this regard, it is described in US Patent No. 5,338,804 that the transparency is lowered if the refractive index difference of the two phase resins is 0.005 or more.

In addition, even if the refractive index of the elastomer rubber is similar to that of PMMA, since the degree of change of the refractive index of each resin constituting the dispersed phase and the continuous phase is different, even if the refractive index is matched at a specific temperature such as room temperature, high transparency can be obtained. Transparency is often reduced at other temperatures, ie high temperatures above room temperature or low temperatures below room temperature.

Ethylene-based copolymer rubber, poly, which is an elastomer rubber, which is disclosed in Japanese Patent Publication No. 46-11035, US Patent Registration No. 4,287,315, and Italian Patent No. 47,946 A89, and which is already known in other literatures. Butadiene, butadiene / alkyl acrylate copolymer, acrylate rubber and the like shows a significant change in refractive index with temperature changes. As an example, when ethylene / vinyl acetate copolymer rubber is used as the impact resistant agent of PMMA, the impact resistance of PMMA is improved and transparent at room temperature, but the transparency changes rapidly with temperature change. In another example, the impact resistance is also increased by using an elastomeric rubber component having a core / shell structure of styrene / butyl acrylate / methyl methacrylate having a refractive index similar to that of PMMA. . On the other hand, the transparency at room temperature is excellent, but has a slight blue light, and also has the disadvantage that the transparency of PMMA greatly decreases when the temperature rises.

It is an object of the present invention to provide a novel transparent thermoplastic resin composition.

Another object of the present invention is to provide a novel transparent thermoplastic resin composition having high gloss and high hardness.

In order to achieve the above object, the transparent thermoplastic resin composition according to the present invention is a graft copolymer 1-30 graft polymerized methacrylic acid ester compound or acrylic acid ester compound, aromatic vinyl compound, vinyl cyan compound to butadiene rubber weight%; 10-50% by weight of an aromatic vinyl compound-vinyl cyan compound copolymer; It consists of 20-70 weight% of polymethylmethacrylate resin.

In the present invention, although not limited in theory, the graft copolymer is used to increase the compatibility of a transparent matrix composed of a polymethylmethacrylate resin and an aromatic vinyl compound-vinyl cyanide compound.

In the present invention, the butadiene-based rubber used in the graft copolymer is a rubber in which a small amount of unsaturated monomer copolymerizable with butadiene or butadiene, such as styrene and acrylonitrile, is copolymerized.

In the present invention, the aromatic vinyl compound is a substituted or unsubstituted styrene monomer, preferably styrene, α-methyl styrene, p-methyl styrene, o-ethyl styrene, p-ethyl styrene or vinyl toluene Styrene is particularly preferred.

In the present invention, the vinyl cyanide compound may be acrylonitrile, methacrylonitrile, ethacrylonitrile, or the like, preferably acrylonitrile.

In the present invention, the methacrylic acid alkyl ester compound or acrylic acid alkyl ester compound is (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, ( It is meta) acrylic acid decyl ester and (meth) acrylic acid lauryl ester, Preferably it is methacrylate.

In the present invention, the butadiene-based rubber is preferably made of a small particle size and a large particle size, so that the final product can satisfy both high transparency and high gloss and impact resistance.

In the practice of the present invention, the small particle size rubber is preferably in the range of 700-1500 mm diameter, more preferably 800-1200 mm diameter. In addition, the large-diameter rubber is preferably in the range of 2000-4000 mm in diameter, more preferably 2500-3500 mm in diameter. If the size of the small particle rubber is too large, the transparency and glossiness is lowered, if less, the impact strength is lowered. In addition, in the case of large particle size rubber, if the size becomes too large or small, there is a problem in that the impact strength is lowered.

In a preferred embodiment of the present invention, the graft copolymer is 5-25 parts by weight of butadiene rubber having an average particle diameter of 700 ~ 1500 kPa so that the final product can maintain high gloss, high impact characteristics; 20-50 parts by weight of butadiene rubber having an average particle diameter of 2000-4000 mm 3; 20-40 parts by weight of methyl methacrylate; 10-20 parts by weight of styrene; It may consist of 1-10 parts by weight of acrylonitrile.

In the present invention, the graft copolymer is a methacrylic acid alkyl ester, an aromatic vinyl compound and an unsaturated nitrile monomer in a rubber latex mixture (R) made of a diene rubber polymer (R ₁ , R ₂ ) having different particle diameters. It is made by graft polymerization by adding and stirring an emulsifier and a dispersant of the monomer mixture and alkylaryl sulfonate salt comprising a.

In the present invention, the graft copolymer is preferably used in the range of 1-30% by weight, more preferably 5-20% by weight. When the amount of the graft copolymer is increased, transparency and processability are lowered due to an increase in the rubber content, and when the amount of the graft copolymer is decreased, the impact strength is lowered.

In the present invention, the polymethyl methacrylate resin is a homopolymer having methyl methacrylate as a main component; Copolymers containing at least one of an alkylacrylate group or an alkylmethacrylate group.

In the present invention, the polymethyl methacrylate may be prepared by suspension polymerization. In the practice of the present invention, a high molecular weight polymethylmethacrylate is obtained by addition reaction of a methylmethacrylate monomer with a polymerization initiator, and product properties are classified according to molecular weight (viscosity). A flow index (230 ° C / 3.8kg) of between 1 and 25 is possible, but preferably between 8 and 18. More than 18 products have good flow, but impact characteristics are inadequate, and below 8, it is impossible to obtain a good product according to the surface of the molded product and the size of the molded product due to the decrease in flow (viscosity increase).

In the practice of the present invention, the polymethyl methacrylate resin preferably uses high flow polymethyl methacrylate in consideration of moldability and impact strength, more preferably Mw is 60,000-120,000, and even more. Preferably Mw is on the order of 80,000 to 95,000. The polymethylmethacrylate may be commercially available and used by various companies, preferably V-150 (Akema, France).

In the present invention, the polymethyl methacrylate resin is more preferably used 20 to 70% by weight in the resin composition. If the content is less than 20% by weight, it is difficult to obtain desired impact strength, scratch resistance, colorability, and the like. If the content is more than 70% by weight, the moldability is poor, resulting in a defect.

In the present invention, the copolymer of the vinyl cyanide compound and the aromatic vinyl compound may be obtained by copolymerization of the vinyl cyanide compound and the aromatic vinyl compound. Preferably, a bulk polymerized product may be used to increase the transparency of the matrix. .

In the practice of the present invention, the vinyl cyanide compound and the aromatic vinyl compound may be used a commercially available styrene-acrylonitrile copolymer, considering the impact characteristics and fluidity, the molecular weight is 100,000 to 140,000 or less The product is desirable. In a preferred embodiment of the invention, the high molecular weight acrylonitrile-styrene copolymer is SAN-310 grade (Kumho Petrochemical, South Korea). For this reason, it is preferable to use a product having an AN content of 25% by weight or less so as to secure transparency of the final product.

In the practice of the present invention, the acrylonitrile-styrene copolymer is preferably used in the range of 10-50% by weight, preferably 15-45% by weight, more preferably 20-40% by weight.

In the present invention, it is preferable that the graft copolymer has a refractive index difference of ± 0.005 or less between a mixture of a vinyl cyanide compound-aromatic vinyl compound copolymer and a polymethyl methacrylate to ensure transparency of the final product. Most preferably, the refractive index is the same.

The present invention in one aspect, 1-30% by weight of butadiene-methyl methacrylate-styrene-acrylonitrile copolymer; 10-50% by weight of acrylonitrile-styrene copolymer; It provides an injection molded article made of a thermoplastic composition consisting of 20-70% by weight of polymethyl methacrylate resin.

The injection molded article according to the present invention has high gloss and high transparency, has good scratch resistance, and can be used as a housing for electronic products such as a TV. In particular, it can be used in an unpainted form.

The present invention in one aspect, 1-30% by weight of butadiene-methylmethacrylate-styrene-acrylonitrile graft copolymer; The butadiene-methyl methacrylate-styrene-acrylonitrile copolymer provides a transparent thermoplastic composition comprising 70 to 99% by weight of a transparent resin having a difference in refractive index within ± 0.005.

In the present invention, the graft copolymer is 5-25 parts by weight of butadiene rubber having an average particle diameter of 700 ~ 1500 kPa; 20-50 parts by weight of butadiene rubber having an average particle diameter of 2000-4000 mm 3; 20-40 parts by weight of methyl methacrylate; 10-20 parts by weight of styrene; 1-10 parts by weight of acrylonitrile, methyl methacrylate, styrene, acrylonitrile is grafted to the butadiene rubber, to provide a thermoplastic transparent resin composition excellent in transparency and impact resistance.

In the present invention, the transparent resin kneaded with the graft copolymer may be a common transparent resin, for example, polystyrene, polymethylmethacrylate, polycarbonate, and styrene-acrylonitrile copolymer or mixtures thereof. have. In a preferred embodiment, the transparent resin is a styrene-acrylonitrile copolymer.

In the present invention, in order to provide processability, thermal stability, color, ultraviolet ray characteristics, and the like to the resin, additives such as conventional stabilizers, pigments, plasticizers, ultraviolet absorbers, lubricants, fillers, and the like may be added.

In the present invention, as a method of blending the thermoplastic composition, a resin composition may be prepared using a general mixed melt processing apparatus such as a Banbury mixer or an extruder.

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

According to the present invention, there is provided a high gloss, high hardness transparent thermoplastic resin composition excellent in transparency and excellent in black colorability and excellent in gloss, hardness, impact strength, processability and scratch resistance.

In the case of using the thermoplastic resin composition of the present invention, the front panel of a TV requiring high gloss can be manufactured by unpainting, thereby reducing the manufacturing cost.

Example

Example 1-5

After mixing sufficiently with a small tumble mixer for uniform mixing with the composition ratio as shown in Table 1, the extrusion temperature in the twin-screw extruder with φ = 25mm was extruded in the range of 220-240 ℃, cooled and solidified to form pellets, and then 80 ℃ After drying for 4 hours in the maintained circulating hot air dryer, change the injection temperature to 220-240 ℃ in the 160-ton injection machine, and make the material specimen to see the general properties of the thermoplastic resin composition of the dried pellet at 65 ℃. In addition, color-chip specimens were fabricated to confirm transparency blackness and scratch resistance, and melt flow index was also measured to examine moldability.

After the prepared specimens were allowed to stand for 24 hours, the melt flow index, impact resistance, surface scratch resistance, colorability, and Haze were measured and shown in Table 1 below.

Comparative Example 1-5

Specimens were prepared in the same manner as in the above-described Examples and compositions as shown in Table 1, and the properties were measured and shown in Table 1.

<Test method>

(1) Meltflow Index (g / 10min)

ASTM D1238 was used and was 220 ° C., 1000 g. The liquidity index was determined to be normal by controlling the state and condition of the product during injection molding, which is over 10 based on actual experiments and field experiences.

(2) Impact resistance (kgfcm / cm)

ASTM D256 method was used, and Notched Izod Impact Strength was measured at 3.2 mm at 23 ° C. The impact property was judged to be stable in the product free fall and fall impact test through the actual experiment and field experience.

(3) surface scratch resistance

The scratches, R-hardness and pencil hardness of plastic products are related. Scratch resistance was determined to be more than Rockwell Hardness 116 and pencil hardness (500g load) H through actual experiments and field experience.

(4) Blackness

Each raw material has a limit to produce black. In particular, in order to produce black on transparent materials, it is necessary to select an appropriate raw material. Based on actual experiments and field experience, it was determined that the L value was 25 or less. Tester: D65

(5) Haze

This test was used to determine the transparency of the resin. This is a necessary requirement where product transparency is required. Based on actual experiments and field experience, Haze 5 or less was determined to be stable.

Table 1

     Item       Example Comparative Example One 2 3 4 One 2 3 4 5 6 Composition (% by weight) A Low viscosity 40 Midpoint 40 40 45 40 20 60 80 50 B High viscosity 40 Midpoint 40 45 40 40 60 20 80 50 C 20 15 15 20 20 20 20 20 20 Antioxidant Pigment Lubricant ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ characteristic Formability MI (220 ℃ / 10kg) 12 14 10 18 5 20 5 25 3 15 Impact (kgfcm / cm) 12 10 10 10 13 10 11 10 11 2 Scratch Resistance Pencil Hardness (500g Load) H H H H H F 2H HB 2H 3H Colorability L 24.5 24.7 24.4 24.5 24.8 26.0 24.4 26.5 23.8 25.0 Haze 2 5 5 2 8 37 18 50 20 One A) Polymethyl methacrylate (medium viscosity: V-150, low viscosity: VH, Akema) B) acrylonitrile-styrene copolymer (KKPC Bulk SAN) (medium viscosity: SAN-310, 326, 330, High Viscosity: SAN-350, 360) C) g-MABS copolymer (KKPC M-560), small particle rubber and large particle rubber mixed small particle rubber: 800-1200 Å (transparent, glossy) Large particle rubber: 2500-3500 Å (to ensure impact)

As shown in Table 1, in Examples 1-4, scratch resistance, black colorability, and basic physical properties are generally better than those of the comparative example, and when the A content is high, scratch resistance and colorability are good. On the other hand, moldability and impact resistance are lowered. In addition, a resin having a good Haze (refractive index) within an appropriate range can be obtained.

Claims (7)

1 to 30% by weight of a graft copolymer obtained by graft polymerization of a butadiene rubber with a methacrylic acid ester compound, an acrylic acid ester compound, an aromatic vinyl compound, and a vinyl cyan compound; 10-50% by weight of an aromatic vinyl compound-vinyl cyan compound copolymer; Transparent thermoplastic resin composition consisting of 20-70% by weight of polymethyl methacrylate resin. The method of claim 1, wherein the polymethyl methacrylate is a transparent thermoplastic resin composition, characterized in that the flow index of 8-18 at 230 ℃ / 3.8kg conditions. 3. The transparent thermoplastic resin composition according to claim 2, wherein the polymethyl methacrylate has a Mw of 60,000-120,000. The transparent thermoplastic resin composition of claim 1, wherein the acrylonitrile-styrene copolymer has an AN content of 25% or less. The method of claim 1, wherein the graft copolymer is 5-25% by weight of small particle rubber of 700-1500 A; 20-50% by weight of large particle rubber of 2000-4000 A; 20-40% by weight methylmethacrylate, 1020% by weight styrene; A thermoplastic resin composition, characterized in that polymerized at 1-10% by weight of acrylonitrile. 5-25% by weight of small particle rubber of 700-1500 A, 20-50% by weight of large particle rubber of 2000-4000 A, 20-40% by weight of methyl methacrylate, 1020% by weight of styrene, and acrylonitrile 1-10 1-30 wt% of graft copolymer consisting of wt%; And 70-99 wt% of transparent resin, The difference in refractive index between the graft copolymer and the transparent resin is ± 0.005 or less, the thermoplastic resin composition. Unpainted TV panel made of the thermoplastic resin composition of claim 1.