KR100877581B1 - Scratch-resistant flame retardant thermoplastic resin composition - Google Patents

Abstract

A scratch-resistant flame retardant thermoplastic resin composition is provided to improve the commercial availability of a methacrylate-based resin and a polycarbonate-based resin and to reduce an injection weld line. A scratch-resistant flame retardant thermoplastic resin composition comprises a base resin 100.0 parts by weight, a flame retardant 1-50 parts by weight and an aromatic vinyl resin 1-30 parts by weight containing rubber component 0-15 weight%. The base resin compises (A) a polycarbonate-based resin 40-90 parts by weight and (B) a methacrylate-based resin 10-60 parts by weight. The flame retardant is a phosphate-based flame retardant or halogen-based flame retardant.

Description

[0001] Scratch-Resistant Flame Retardant Thermoplastic Resin Composition [

FIG. 1 (a) is a transmission electron microscope (TEM) photograph of the specimen prepared in Example 1, and FIG. 1 (b) is a transmission electron microscope (TEM) photograph of the specimen prepared in Comparative Example 1.

Field of invention

The present invention relates to a flame retardant thermoplastic resin composition having excellent scratch resistance. More specifically, the present invention relates to a thermoplastic resin composition having excellent scratch resistance and flame retardancy, including a flame retardant and an aromatic vinyl resin, with respect to a base resin comprising a polycarbonate resin and a methacrylate resin.

BACKGROUND OF THE INVENTION

Electrical and electronic products are demanding various characteristics of resin in accordance with the tendency of enlargement, specialization, and weight reduction. In particular, since the appearance of exterior materials is more important, the scratch resistance of the resin body is one of the important performances as a high gloss material is required. In recent years, there has been a growing demand for flame retardancy due to stability problems with fire.

Methods that can be accessed to simultaneously achieve scratch resistance and flame retardancy include polystyrene (PC) resins and methacrylate resins, and more preferably polymethylmethacrylate (PMMA).

Polycarbonate resin is excellent in mechanical strength and is excellent in transparency, thermal stability, self-extinguishing property and dimensional stability, and is widely used in electrical and electronic products and automobile parts. In addition, since flame retardancy due to chemical structure can be easily achieved, excellent flame retardancy can be achieved with a small amount of flame retardant as compared with general-purpose polymers. However, since the scratch resistance of the polycarbonate itself is not so good as the pencil hardness B, there is a problem that satisfactory scratch resistance can not be achieved with polycarbonate resin alone. On the other hand, in the case of the polymethyl methacrylate resin having excellent scratch resistance, the pencil hardness of the resin itself is very good to about 3H, but it has a drawback that it is very difficult to achieve flame retardancy with the conventional flame retardant. Therefore, it is possible to complement the scratch resistance and flame retardancy characteristics mutually problematic by blending PC resin and PMMA resin.

However, since PC and PMMA resins are incompatible with each other, they are separated into respective phases even if they are melt-kneaded at a high temperature. In addition, since the refractive index of PC is 1.59 and the refractive index of PMMA is 1.49, it is difficult to color the PC and PMMA because of the scattering of light by pearl light and color with high chromaticity, and the fusion bonding line is very visible It has disadvantages. When the conventional phosphorus flame retardant is injected into the PC and the PMMA, the compatibility of the polycarbonate and the methacrylate resin tends to be partially improved owing to the plasticizing effect of the phosphorus flame retardant, but the shear force and temperature during the extrusion and injection processes There is a problem that phase separation occurs. Therefore, it is very difficult to apply PC and PMMA as a jacket of electrical and electronic products substantially.

Korean Patent Publication No. 2004-0079118 discloses a method for improving the compatibility by lowering the molecular weight of the polycarbonate during the kneading process using a metal stearate ester. However, this method has the disadvantage that the mechanical properties are drastically lowered.

U.S. Patent No. 5,280,070 discloses a transparent PC / PMMA blend prepared by using syndiotactic polymethylmethacrylate on polycarbonate, but it is difficult to commercially produce syndiotactic polymethylmethacrylate resin.

In addition, U.S. Patent No. 4,027,073 discloses a method of coating a surface of a resin to improve scratch resistance, but it has a disadvantage that it must be further processed.

Accordingly, in order to solve the above problems, the present inventors have found that the addition of an aromatic vinyl resin to a base resin composed of a polycarbonate resin and a methacrylate resin significantly improves the compatibility and prevents phase separation, It has been possible to develop a thermoplastic resin composition which not only remarkably reduces the weld line at the time but also can easily color the high-chromium resin.

It is an object of the present invention to provide an scratch-resistant flame retardant thermoplastic resin composition in which the compatibility of a polycarbonate resin and a methacrylate resin is greatly improved.

Another object of the present invention is to provide an scratch-resistant flame retardant thermoplastic resin composition in which the weld line is remarkably reduced upon injection.

It is still another object of the present invention to provide an scratch-resistant flame retardant thermoplastic resin composition which is easy to color with a high degree of color.

It is still another object of the present invention to provide a thermoplastic resin composition having both mechanical strength and scratch resistance.

It is still another object of the present invention to provide an scratch resistant thermoplastic resin composition excellent in flame retardancy.

Another object of the present invention is to provide an scratch-resistant flame retardant thermoplastic resin composition excellent in transparency and appearance.

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

SUMMARY OF THE INVENTION

(A) 40 to 90 parts by weight of a polycarbonate resin; And (B) 10 to 60 parts by weight of a methacrylate resin, (C) 1 to 50 parts by weight of a flame retardant; And (D) 1 to 30 parts by weight of an aromatic vinyl resin.

The methacrylate resin (B) is a copolymer of 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of monofunctional unsaturated monomer.

The flame retardant (C) is a phosphorus flame retardant or a halogen-based flame retardant.

The aromatic vinyl resin (D) may be prepared by copolymerizing 50 to 100% by weight of an aromatic vinyl compound and from the group consisting of acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, N-substituted maleimide, 0 to 50% by weight of the selected monomer.

The aromatic vinyl resin (D) may further contain a rubber component in a range of 15 wt% or less.

In one embodiment of the present invention, the resin composition may further comprise 1 to 30 parts by weight of the impact modifier (E) based on 100 parts by weight of the base resin.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(A) a polycarbonate resin

The polycarbonate resin (A) can be prepared by reacting a diphenol represented by the following formula (1) with phosgene, halogenformate or carbonic acid diester.

[Chemical Formula 1]

(Wherein A represents a single bond, C ₁ -C ₅ alkylene, C ₁ -C ₅ alkylidene, C ₅ -C ₆ cycloalkylidene, -S- or -SO ₂ -).

Specific examples of the diphenol represented by Formula 1 include hydroquinol, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) 2-methylbutane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane, 2,2-bis- (3-chloro-4-hydroxyphenyl) , 2-bis- (3,5-dichloro-4-hydroxyphenyl) -propane, and the like. Of these, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dichloro- Hydroxyphenyl) -cyclohexane are preferred, and 2,2-bis- (4-hydroxyphenyl) -propane, also referred to as bisphenol-A, is particularly preferred. A polycarbonate resin of the present invention is 10,000 to 200,000 weight-average molecular weight (M _w), and preferably from 15,000 to 80,000.

The polycarbonate resin of the present invention may be a homopolymer using one dihydric phenolic compound or a copolymer using two or more dihydric phenolic compounds or a mixture thereof.

Typically, the polycarbonate resin may have the form of a linear polycarbonate resin, a branched polycarbonate resin, or a polyester carbonate copolymer resin. The polycarbonate resin to be used in the present invention is not limited to a specific form, and a linear polycarbonate resin, a branched polycarbonate resin, or a polyester carbonate copolymer resin may all be used.

As the linear polycarbonate resin, a bisphenol A-based polycarbonate resin may be used, but is not limited thereto. The branched polycarbonate resin may be prepared by adding 0.05 to 2 mol% of a tri- or more polyfunctional compound, for example, a compound having a trivalent or higher phenol group, based on the total amount of diphenols used for polymerization have. For example, those prepared by reacting a polyfunctional aromatic compound such as trimellitic anhydride or trimellitic acid with a dihydric phenolic compound and a carbonate precursor may be used, but the present invention is not limited thereto. As the polyester carbonate copolymer resin, those prepared by reacting a bifunctional carboxylic acid with a dihydric phenol and a carbonate precursor may be used, but the present invention is not limited thereto. The linear polycarbonate resin, the branched polycarbonate resin and the polyester carbonate copolymer resin may be used alone or in combination of two or more.

In the present invention, the polycarbonate resin (A) is used in an amount of 40 to 90 parts by weight, preferably 50 to 85 parts by weight, more preferably 55 to 80 parts by weight. Since the polycarbonate resin has a role of facilitating the impartation of flame retardancy, when the amount is less than 40 parts by weight, flame retardancy and mechanical strength are lowered. When 90 parts by weight or more is applied, it is difficult to expect improvement in scratch resistance.

(B) a methacrylate resin

The methacrylate resin (B) in the present invention is a copolymer of 50 to 100% by weight of methyl methacrylate (MMA) and 0 to 50% by weight of monofunctional unsaturated monomer.

At this time, methyl methacrylate (MMA) as a main component preferably retains at least 50% by weight of the total monomers. When the MMA is less than 50% by weight, transparency and mechanical strength of the polymerized methacrylic resin may be lowered.

The monofunctional unsaturated monomer is not particularly limited as a copolymerizable monomer. Examples thereof include methacrylates such as ethyl methacrylate, propyl methacrylate, butyl methacrylate and benzyl methacrylate, phenyl methacrylate and glycidyl methacrylate; Acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; Unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and acid anhydrides such as maleic anhydride; And monofunctional vinyl group-containing monomers such as styrene, acrylonitrile, methacrylonitrile, and the like. These may be used alone or in combination of two or more.

The methacrylate resin (B) may be polymerized by a conventionally known method, and bulk polymerization, emulsion polymerization, suspension polymerization, or the like may be applied, but is not limited thereto.

In order to control the molecular weight and thermal stability of the methacrylate resin (B), a chain transfer agent and an antioxidant may be used, and this is easily performed by a person skilled in the art to which the present invention belongs. .

The methacrylate resin (B) used in the present invention may be used in an amount of 10 to 60 parts by weight, preferably 20 to 50 parts by weight, and more preferably 25 to 45 parts by weight, based on the base resin. When the methacrylate resin (B) is used in an amount of less than 10 parts by weight, it is difficult to impart scratch resistance, and when the amount of the methacrylate resin (B) is more than 60 parts by weight, the flame retardancy is very low and it is difficult to achieve flame retardancy with a phosphorus flame retardant .

(C) Flame retardant

The flame retardant used in the present invention may be a phosphorus flame retardant or a halogen-based flame retardant, preferably a phosphorus-based flame retardant.

Examples of the phosphorus flame retardant include phosphates, phosphonates, phosphinates, phosphine oxides, phosphazenes, and metal salts thereof. It is not. These may be used alone or in combination of two or more.

The halogen-based flame retardant is preferably a halogen-based compound capable of melting at a normal processing temperature, more specifically a compound having a melting point or softening point at 250 캜 or lower.

In the present invention, the flame retardant (C) is used in an amount of 1 to 50 parts by weight, preferably 5 to 30 parts by weight, more preferably 10 to 27 parts by weight based on 100 parts by weight of the base resin. If it exceeds 50 parts by weight, the impact strength and permeability may be lowered.

(D) an aromatic vinyl resin

The aromatic vinyl resin (D) according to the present invention is a polymer comprising 50 to 100% by weight of an aromatic vinyl monomer and 0 to 50% by weight of a monomer copolymerizable with the aromatic vinyl monomer.

Examples of the aromatic vinyl monomer include styrene, alpha-methylstyrene, para-methylstyrene, and the like, but are not limited thereto. These may be used alone or in combination of two or more. Double styrene is most preferred. The aromatic vinyl-based monomer constitutes the main component of the aromatic vinyl-based resin (D) and is used in an amount of 50 to 100% by weight. When used within the above range, the effect of improving the compatibility between the polycarbonate resin and the methacrylate resin is excellent.

Examples of the monomer copolymerizable with the aromatic vinyl monomer include acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, and N-substituted maleimide. These monomers may be used alone or in admixture of two or more.

The aromatic vinyl resin (D) may be incorporated with a rubber component as required. The rubber component is preferably contained in an amount of 0 to 15% by weight. Examples of the rubber include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene), saturated rubbers obtained by hydrogenating the diene rubbers, acrylic rubbers such as isoprene rubbers and poly Rubber and an ethylene-propylene-diene monomer terpolymer (EPDM). These may be used alone or in combination of two or more. Of these, a diene rubber is particularly preferable, and a butadiene rubber is more preferable.

The aromatic vinyl resin (D) can be produced by known polymerization methods such as ordinary emulsion polymerization, suspension polymerization and bulk polymerization, but is not limited thereto.

When a polystyrene resin is applied to a composition containing polycarbonate, a methacrylate resin and a flame retardant, the compatibility between the polycarbonate and the methacrylate resin is remarkably improved so that phase separation does not occur, resulting in good colorability and phase separation It is possible to obtain a resin composition excellent in scratch resistance and flame retardancy.

The aromatic vinyl resin (D) of the present invention is applied in an amount of 1 to 30 parts by weight based on 100 parts by weight of the base resin. More preferably 5 to 20 parts by weight, and most preferably 6 to 15 parts by weight. When the amount of the polystyrene-based resin is less than 1 part by weight, it does not help commercialization of the polycarbonate and methacrylate. When the amount of the polystyrene-based resin is more than 30 parts by weight, mechanical properties and impact resistance may be lowered.

(E) Impact reinforcement

In the present invention, a graft copolymer or an olefin-based copolymer may be used as an impact modifier.

The graft copolymer is prepared by grafting a monomer capable of graft copolymerization to a rubbery polymer.

Examples of the graft copolymerizable monomers include styrene, alpha-methylstyrene; Alkyl substituted styrenes; Acrylonitrile; Methacrylonitrile; Methyl methacrylate; Maleic anhydride; Alkyl or phenyl nucleus-substituted maleimide, etc. These may be used alone or in admixture of two or more.

The content of the rubbery polymer is preferably 20 to 80% by weight.

The rubbery polymer may be at least one member selected from the group consisting of a diene rubber, an acrylate rubber and a silicone rubber, and more specifically, a diene rubber including butadiene and isoprene; Acrylate systems including methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, hexyl methacrylate, 2-ethylhexyl methacrylate and the like; Hexamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, and the like. Cyclosiloxane, and mixtures thereof. In addition, polyolefin-based rubbers such as ethylene / propylene rubber and terpolymer of ethylene-propylene-diene (EPDM) can be used.

The impact modifier used in the present invention may be selectively applied depending on the application, and is applied in an amount of 1 to 30 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the base resin.

In the method for producing a thermoplastic resin according to the present invention, additives such as antistatic agents such as polytetrafluoroethylene, weathering stabilizers, compatibilizers, antioxidants, plasticizers, heat stabilizers, light stabilizers, pigments, dyes and inorganic additives are added . These may be used alone or in combination of two or more.

The resin composition of the present invention can be produced by a known method for producing a resin composition. For example, the components of the present invention and other additives may be simultaneously mixed and then melt-extruded in an extruder and produced in the form of pellets.

The composition of the present invention can be used for the molding of various products, and is particularly used for the production of electrical and electronic products such as housings for TVs and office automation equipments.

The invention may be better understood by reference to the following examples, which are intended to be illustrative of the invention and are not intended to limit the scope of protection which is defined by the appended claims.

Example

The specifications of each component used in the following examples and comparative examples are as follows.

(A) Polycarbonate resin (PC)

Panlite L-1225 Grade from Teijin Co., Japan was used.

(B) a methyl methacrylate resin

PMMA (IH830 Grade) manufactured by LG MMA was used.

(C) Flame retardant

Bisphenol A diphosphate (CR-741) manufactured by Daihachi Chemical Co., Ltd. was used.

(D) an aromatic vinyl resin

GPPS (HF-2660S Grade), a polystyrene resin manufactured by Cheil Industries, was used.

(E) Impact reinforcement

A methyl methacrylate-butadiene-ethyl acrylate copolymer (Metablen C223-A Grade) from MRC was used.

(F) Polytetrafluoroethylene (PTFE)

Teflon (trade name) 7AJ manufactured by Dupont Co., USA was used.

Example  1-2

The above components were added in the amounts shown in Table 1 and extruded in a conventional twin-screw extruder at a temperature in the range of 220 to 260 DEG C. The pellets were dried at 80 DEG C for 3 hours The test specimens for impact, flame retardancy and pencil hardness were prepared by injection molding at a molding temperature of 250 ° C and a mold temperature of 60 ° C in an 8 oz injection molding machine.

Comparative Example  1-2

Except that the aromatic vinyl resin (D) was not used in Examples 1 and 2, respectively.

How to measure property

(1) Izod impact strength: Measured according to ASTM D-256 standard (kgf · cm / cm) for 1/8 "thick specimens.

(2) Flame retardancy: The flame resistance of the specimens having a thickness of 2.0 mm was measured according to the UL 94 V flame retarding specification.

(3) Pencil hardness: The sample was left to stand at 23 占 폚 relative humidity 50% for 48 hours, and the pencil hardness was measured according to JIS K 5401 standard.

The scratch resistance is evaluated by 3B, 2B, B, HB, F, H, 2H and 3H according to the pencil hardness results. The higher the H value, the better the scratch resistance. The higher the B value, Respectively.

(4) Transmittance: A 3 mm thick specimen was measured using a Nippon Denshoku permeability meter.

(5) Appearance: The sharpness of the fusion fusion line (the joint surface formed by the two flows at the time of melt injection) was evaluated with the naked eye.

The morphology of the composition of Example 1 and Comparative Example 1 was taken at a magnification of 30,000 times using a transmission electron microscope (TEM) after the specimen was treated with OsO4 and RuO4 each using a second order, Respectively.

As shown in Table 1, in the case of Example 1-2, it was confirmed that both the scratch resistance and the V0 flame retardancy of the pencil hardness F or more and the appearance and the impact strength were good. In general, when polystyrene is added, the impact resistance is lowered. However, in the case of the present composition, the impact strength is rather improved. The reason is shown in the TEM photograph of Example 1 and Comparative Example 1 shown in Fig. The circular dark color particles show rubber particles and the small bright color particle shape of Comparative Example 1 shows a dispersed PMMA phase. This separated PMMA phase has a morphology showing almost complete dispersibility as shown in Example 1 by adding polystyrene. As a result, all of the physical properties such as the impact strength and the appearance and transmittance of the resin were improved.

Disclosure of the Invention An object of the present invention is to provide a polyolefin-based resin composition and a methacrylate-based resin composition which are improved in compatibility with a polycarbonate-based resin and a methacrylate-based resin, exhibit a remarkably reduced weld line during injection, And has an effect of providing the scratch-resistant flame retardant thermoplastic resin composition having excellent flame retardance, transparency and appearance.

 It will be understood by those skilled 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.

Claims (9)

(A) 40 to 90 parts by weight of a polycarbonate resin; And (B) 10 to 60 parts by weight of a methacrylate resin; Based on 100 parts by weight of the base resin, (C) 1 to 50 parts by weight of a flame retardant; And (D) 1 to 30 parts by weight of an aromatic vinyl resin containing 0 to 15% by weight of a rubber component; Wherein the flame retardant thermoplastic resin composition is a thermosetting resin composition. The scratch-resistant flame-retardant thermoplastic resin composition according to claim 1, wherein the methacrylate resin (B) is a copolymer of 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of monofunctional unsaturated monomer. The method according to claim 2, wherein the monofunctional unsaturated monomer is selected from the group consisting of methacrylates including ethyl methacrylate, propyl methacrylate, butyl methacrylate, benzyl methacrylate, phenyl methacrylate and glycidyl methacrylate ; Acrylates including methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; Wherein the thermoplastic resin composition is selected from the group consisting of unsaturated carboxylic acids including acrylic acid, methacrylic acid, maleic anhydride, styrene, acrylonitrile, methacrylonitrile, and mixtures thereof. The scratch-resistant flame retardant thermoplastic resin composition according to claim 1, wherein the flame retardant (C) is a phosphorus-based flame retardant or a halogen-based flame retardant. The phosphorus flame retardant according to claim 4, wherein the phosphorus flame retardant is at least one selected from the group consisting of phosphate, phosphonate, phosphinate, phosphine oxide, phosphazene, By weight of a flame retardant thermoplastic resin composition. The aromatic vinyl resin composition according to claim 1, wherein the aromatic vinyl resin (D) comprises 50 to 100% by weight of an aromatic vinyl compound and at least one member selected from the group consisting of acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, And 0 to 50% by weight of a monomer selected from the group consisting of a mixture of two or more monomers. The resin composition according to claim 1, wherein the resin composition comprises (C) 100 parts by weight of a base resin comprising (A) 55 to 75 parts by weight of a polycarbonate resin and (B) 25 to 45 parts by weight of a methacrylate resin, To 30 parts by weight of a polystyrene resin and (D) 1 to 30 parts by weight of a polystyrene resin. The scratch-resistant flame retardant thermoplastic resin composition according to claim 1, wherein the resin composition further comprises an impact modifier (E) in an amount of 1 to 30 parts by weight based on 100 parts by weight of the base resin. 9. The resin composition according to any one of claims 1 to 8, wherein the resin composition is selected from the group consisting of a dripping inhibitor, an antioxidant, a plasticizer, a heat stabilizer, a light stabilizer, a compatibilizer, a weather stabilizer, a pigment, a dye, Wherein the flame retardant thermoplastic resin composition contains at least one additive.

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