KR101549731B1 - (meth)acrylic copolymer, method for preparing the same and article comprising the same - Google Patents

Abstract

상기 화학식 1에서, R₁은 수소 원자 또는 메틸기이고, R₂는 치환 또는 비치환된 탄소수 1 내지 20의 탄화수소기이고, R₃ 및 R₄는 각각 독립적으로 치환 또는 비치환된 탄소수 6 내지 20의 환형 탄화수소기이며, m은 1 내지 10의 정수이고, n은 0 내지 5의 정수이다.The (meth) acrylic copolymer of the present invention is a copolymer of a monomer mixture containing a phosphorus-based (meth) acrylic monomer represented by the following formula (1) and a monofunctional unsaturated monomer. The (meth) acrylic copolymer has improved refractive index and has excellent flame retardance, transparency, scratch resistance and environment friendliness.
[Chemical Formula 1]

Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, and R ₃ And R ₄ are each independently a substituted or unsubstituted cyclic hydrocarbon group having 6 to 20 carbon atoms, m is an integer of 1 to 10, and n is an integer of 0 to 5.

Description

TECHNICAL FIELD [0001] The present invention relates to a (meth) acrylic copolymer, a method for producing the same, and a molded article comprising the same. METHOD FOR PREPARING THE SAME AND ARTICLE COMPRISING THE SAME [0002]

The present invention relates to a (meth) acrylic copolymer, a process for producing the same, and a molded article comprising the same. More specifically, the present invention relates to a (meth) acrylic copolymer having improved refractive index and excellent flame retardancy, transparency, scratch resistance and environment friendliness by introducing a high refractive index (meth) acrylic monomer and a high refractive index phosphorus (meth) A production method thereof, and a molded article comprising the same.

The thermoplastic resin has a lower specific gravity than glass or metal and is excellent in properties such as moldability and impact resistance. In recent years, with the trend of low cost, large size, and light weight of electric and electronic products, plastic products using thermoplastic resin are rapidly replacing the area where conventional glass or metal was used and widening the use area from electric and electronic products to automobile parts. In particular, demand for transparent resins is increasing due to thinning of electrical and electronic products and changes in design concept. Accordingly, there is a growing demand for functional transparent materials that impart functionality such as scratch resistance and flame retardancy to existing transparent resins.

As a conventional transparent scratch material, there is an acrylic resin represented by polymethyl methacrylate (PMMA). The PMMA is excellent in transparency, weather resistance, mechanical strength, surface gloss and adhesive force, and particularly has excellent scratch resistance, but has a very weak impact resistance and flame retardancy.

In order to increase the impact resistance while maintaining excellent transparency of the PMMA, there is a method of using an acrylic impact modifier having the same refractive index as that of PMMA. However, the acryl-based impact modifier has a lower impact efficiency than the butadiene-based impact modifier and has a disadvantage that it does not have sufficient impact resistance. Further, there is a method of adding a flame retardant agent to reinforce the flame retardancy of PMMA, but it is difficult to obtain sufficient flame retardancy by the above method, and the physical properties such as heat resistance and impact property may be deteriorated. There is a problem of deterioration. Accordingly, until now, there has been no report of softening of the transparent acrylic resin alone.

In order to overcome the above problems, a method of copolymerizing a flame-retardant high-refractive monomer with PMMA resin was developed. However, conventionally developed copolymers having a flame retardant high refractive monomer introduced therein have a limitation in increasing the refractive index, and it is difficult to exhibit flame retardancy by adding a small amount of a flame retardant, and the mechanical properties including heat resistance are deteriorated when the flame retardant is added .

An object of the present invention is to provide a (meth) acrylic copolymer having a high refractive index and excellent flame retardancy, a process for producing the same, and a molded article comprising the same.

Another object of the present invention is to provide an environmentally friendly flame retardant (meth) acrylic copolymer excellent in transparency, scratch resistance and impact resistance, a process for producing the same, and a molded article comprising the same.

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

One aspect of the present invention relates to a (meth) acrylic copolymer. The (meth) acrylic copolymer is a copolymer of a monomer mixture comprising a phosphorus-based (meth) acrylic monomer represented by the following formula (1) and a monofunctional unsaturated monomer:

[Chemical Formula 1]

Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, and R ₃ And R ₄ are each independently a substituted or unsubstituted cyclic hydrocarbon group having 6 to 20 carbon atoms, m is an integer of 1 to 10, and n is an integer of 0 to 5.

In an embodiment, the content of the phosphorus-containing (meth) acrylic monomer is 1 to 50% by weight, and the content of the monofunctional unsaturated monomer is 50 to 99% by weight.

In an embodiment, the monofunctionally unsaturated monomer is an alkyl (meth) acrylate having 1 to 8 carbon atoms; Unsaturated carboxylic acids containing (meth) acrylic acid; Acid anhydrides including maleic anhydride; (Meth) acrylate containing a hydroxy group; (Meth) acrylamide; Unsaturated nitrile; Allyl glycidyl ether; Glycidyl methacrylate; And an aromatic vinyl-based monomer.

In an embodiment, the (meth) acrylic copolymer may have a weight average molecular weight of 5,000 to 500,000 g / mol.

In an embodiment, the (meth) acrylic copolymer may have a refractive index of 1.490 to 1.590 at a thickness of 2.5 mm.

In the specific examples, the (meth) acrylic copolymer is a specimen having a thickness of 3.2 mm and the flame retardancy measured according to UL94 may be V2 or more.

In the specific examples, the (meth) acrylic copolymer is a specimen having a thickness of 2.5 mm, and the total light transmittance measured according to ASTM D1003 may be 90% or more.

In an embodiment, the (meth) acrylic copolymer may be selected from the group consisting of flame retardants, surfactants, nucleating agents, coupling agents, fillers, plasticizers, impact modifiers, lubricants, antibacterial agents, release agents, heat stabilizers, antioxidants, light stabilizers, An antistatic agent, a pigment, and a dye.

Another aspect of the present invention relates to a process for producing the (meth) acrylic copolymer. The production method comprises the step of adding a polymerization initiator to a monomer mixture containing a phosphorus-containing (meth) acrylic monomer represented by the formula (1) and a monofunctional unsaturated monomer, and polymerizing.

In an embodiment, the polymerization initiator is a radical polymerization initiator, and the polymerization may be a suspension polymerization.

Preferably, the suspension polymerization can be carried out in the presence of a suspension stabilizer and a chain transfer agent.

In an embodiment of the present invention, it is preferable to add a flame retardant, a surfactant, a nucleating agent, a coupling agent, a filler, a plasticizer, an impact modifier, a lubricant, an antibacterial agent, a releasing agent, a heat stabilizer, an antioxidant, a light stabilizer, a compatibilizer, It is possible to further polymerize by adding at least one kind of dye.

Another aspect of the present invention relates to a molded article. The molded article is formed from the (meth) acrylic copolymer.

The present invention has the effect of providing an environmentally friendly flame retardant (meth) acrylic copolymer having a high refractive index and excellent flame retardancy, and excellent in transparency, scratch resistance and impact resistance, a method for producing the same, and a molded article comprising the same.

Hereinafter, the present invention will be described in detail.

The (meth) acrylate copolymer according to the present invention is a copolymer of a monomer mixture comprising a phosphorus-based (meth) acrylic monomer represented by the following formula (1) and a monofunctional unsaturated monomer.

[Chemical Formula 1]

Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, for example, a substituted or unsubstituted C1-C20 (having 1 to 20 carbon atoms) linear , A branched or cyclic alkylene group, a substituted or unsubstituted C6-C20 arylene group, preferably a substituted or unsubstituted C1-C10 linear, branched or cyclic alkylene group, a substituted or unsubstituted C6-C10 An arylene group, more preferably a C1-C4 linear alkylene group. R ₃ And R ₄ are each independently a substituted or unsubstituted cyclic hydrocarbon group having 6 to 20 carbon atoms, for example, a substituted or unsubstituted C6-C20 cycloalkyl group or an aryl group, preferably a substituted or unsubstituted C6 C10 < / RTI > m is an integer of 1 to 10, and n is an integer of 0 to 5. When n is 0, it represents a single bond, and the phosphorus containing heterocyclic group forms a hexagonal ring.

"(Meth) acrylic" means "acrylic" and "methacrylic" are both possible unless otherwise specified herein. For example, "(meth) acrylate" means that both "acrylate" and "methacrylate" are possible. Refers to a linear, branched or cyclic, saturated or unsaturated hydrocarbon group wherein the hydrogen atom in the compound is a halogen atom (F, Cl, Br, I), a hydroxy group, a nitro group, , An amino group, an azido group, an amidino group, a hydrazino group, a hydrazino group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C1-C20 alkoxy group, a C6-C30 aryl group, a C6-C30 aryloxy group, C30 cycloalkenyl group, a C3-C30 cycloalkynyl group, or a combination thereof.

Specific examples of the phosphorus (meth) acrylic monomers used in the present invention include 9,10-dihydro-9-oxa-10-phosphaphene-10-oxymethyl (meth) But is not limited to.

The refractive index of the phosphorus (meth) acrylic monomer may be, for example, 1.550 to 1.690, preferably 1.590 to 1.660. Within the above range, a (meth) acrylic copolymer having a high refractive index can be obtained.

The content of the phosphorus (meth) acrylic monomer in the total monomer mixture is 1 to 50% by weight, preferably 5 to 40% by weight. Within the above range, a (meth) acrylic copolymer having excellent flame retardancy can be obtained without deteriorating other physical properties.

The monofunctional unsaturated monomer used in the present invention is a monomer containing one unsaturated group, for example, an alkyl (meth) acrylate having 1 to 8 carbon atoms; Unsaturated carboxylic acids containing (meth) acrylic acid; Acid anhydrides including maleic anhydride; (Meth) acrylate containing a hydroxy group; (Meth) acrylamide; Unsaturated nitrile; Allyl glycidyl ether; Glycidyl methacrylate; Aromatic vinyl monomers, mixtures thereof, and the like. These may be used alone or in combination of two or more.

Non-limiting examples of the monofunctional unsaturated monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2- Acrylic acid, methacrylic acid, maleic anhydride, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, monoglycerol acrylate, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile , Allyl glycidyl ether, glycidyl methacrylate, styrene, alpha-methylstyrene, and the like. Preferably an alkyl (meth) acrylate having 1 to 8 carbon atoms, more preferably an alkyl (meth) acrylate having 1 to 4 carbon atoms. In this case, superior scratch resistance and transparency can be achieved.

In one embodiment, the monofunctional unsaturated monomer may be a mixture of methacrylate and acrylate. In this case, the weight ratio of methacrylate to acrylate (methacrylate: acrylate) may be from 15: 1 to 45: 1. And can have better thermal stability and fluidity in the above range.

The content of the monofunctional unsaturated monomer is 50 to 99% by weight, preferably 60 to 95% by weight, of the total monomers. Excellent balance of scratch resistance, fluidity, transparency and flame retardancy in the above range can be obtained.

The (meth) acrylic copolymer according to the present invention may further contain, if necessary, additives such as a flame retardant, a surfactant, a nucleating agent, a coupling agent, a filler, a plasticizer, an impact modifier, a lubricant, an antibacterial agent, a releasing agent, a heat stabilizer, An additive such as an antioxidant, an inorganic additive, an antistatic agent, a pigment, and a dye. These additives may be added during the polymerization process or may be added to the copolymer in the pelletization process (extrusion process, etc.), but the method and amount thereof are not particularly limited.

Non-limiting examples of the antioxidant include octadecyl 3- (3,5-di-tert-butyl-4-hydrophenyl) propionate, triethylene glycol-bis- Methylphenyl) propionate, 2,6-di-tertiary-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl- Octadecyl-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tri (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, distearyl thiol dipropio Naphthoic acid, methanesulfonic acid, methanesulfonic acid, methanesulfonic acid, methanesulfonic acid, methanesulfonic acid, and the like.

The (meth) acrylic copolymer of the present invention may have a weight average molecular weight of 5,000 to 500,000 g / mol, preferably 10,000 to 250,000 g / mol, more preferably 20,000 to 100,000. The impact resistance can be excellent in the above range.

The (meth) acrylic copolymer may have a refractive index of 1.490 to 1.590, preferably 1.492 to 1.550 at a thickness of 2.5 mm, and a specimen of 3.2 mm may have a flame retardancy of at least V2, for example, V0.

The (meth) acrylic copolymer may have a total light transmittance of 90% or more, preferably 91 to 98%, measured according to ASTM D1003, with a thickness of 2.5 mm.

The (meth) acrylic copolymer according to the present invention can be produced by a conventional polymerization method known in the field of copolymer production, for example, bulk polymerization, emulsion polymerization, suspension polymerization and the like. For example, And then introducing an initiator and polymerizing.

In an embodiment, the polymerization initiator is a radical polymerization initiator, and the polymerization may be a suspension polymerization in consideration of refractive index and the like, and the suspension polymerization may be carried out in the presence of a suspension stabilizer and a chain transfer agent. That is, a radical polymerization initiator and a chain transfer agent are added to the monomer to prepare a reaction mixture, and the resulting reaction mixture is added to an aqueous solution in which the suspension stabilizer is dissolved to prepare the (meth) acrylic copolymer of the present invention . Here, the additive may be further added.

As the polymerization initiator, a conventional radical polymerization initiator known in the polymerization field can be used. Examples of the polymerization initiator include octane oleyl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, monochlorobenzoyl peroxide, But are not limited to, benzoyl peroxide, p-methylbenzoyl peroxide, tert-butyl perbenzoate, azobisisobutyronitrile and azobis- (2,4-dimethyl) -valeronitrile . These may be used alone or in combination of two or more. The polymerization initiator may be included in an amount of 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, based on 100 parts by weight of the monomer mixture.

The chain transfer agent can be used for controlling the weight average molecular weight of the (meth) acrylate copolymer and improving the thermal stability. The weight average molecular weight can be controlled by the content of the polymerization initiator contained in the monomers. However, when the polymerization reaction is stopped by the chain transfer agent, the end of the chain becomes the second carbon structure. This is stronger than the end of a chain having a double bond generated when a chain transfer agent is not used. Therefore, the addition of the chain transfer agent can improve the thermal stability and, ultimately, improve the optical properties of the (meth) acrylate copolymer.

The chain transfer agent may be a conventional chain transfer agent known in the polymerization field, and examples thereof include n-butylmercaptan, n-octylmercaptan, n-dodecylmercaptan, t-dodecylmercaptan, isopropyl Alkyl mercaptans of the form CH ₃ (CH ₂ ) _n SH (n is an integer from 1 to 20) including mercaptans and n-amyl mercaptans; Halogen compounds including carbon tetrachloride and the like; And aromatic compounds including alpha methyl styrene dimer or alpha ethyl styrene dimer, and the like, but the present invention is not limited thereto. These may be used alone or in combination of two or more. Generally, the amount of the chain transfer agent to be used varies depending on the kind, but 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight, based on 100 parts by weight of the monomer may be used. Within the above range, excellent heat resistance can be obtained, and the molecular weight of the polymer is prevented from being excessively low, so that the mechanical properties are excellent.

In the process for producing the (meth) acrylic copolymer of the present invention, the suspension stabilizer and the conventional suspension stabilizer may be further used.

Examples of the suspension stabilizer include organic suspension stabilizers such as polyalkyl acrylate-acrylic acid, polyolefin-maleic acid, polyvinyl alcohol and cellulose, and inorganic suspension stabilizers such as tricalcium phosphate, but are not limited thereto.

Disodium hydrogenphosphate, sodium dihydrogenphosphate and the like may be used as the suspension stabilizer, and sodium sulfate and the like may be added to control solubility characteristics of the water-soluble polymer and the monomer.

In the production method of the (meth) acrylic copolymer of the present invention, the polymerization temperature and the polymerization time can be appropriately controlled. For example, at a polymerization temperature of 65 to 125 캜, preferably 70 to 120 캜, for 2 to 8 hours.

After the polymerization is completed, the (meth) acrylic copolymer in the form of particles may be obtained through cooling, washing, dehydration and drying processes.

The (meth) acrylic copolymer according to the present invention can form a molded article. As a molding method for producing the molded article, extrusion, injection molding, casting or the like may be applied, but the present invention is not limited thereto. The molding method is well known to those of ordinary skill in the art to which the present invention pertains. For example, after the (meth) acrylic copolymer and the additives are mixed as necessary, they are melt-extruded in an extruder to produce pellets, and the pellets can be used to produce injection molded articles and compression molded articles.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Example

Examples 1-4

(A) 9,10-dihydro-9-oxa-10-phosphaphene-10-oxymethyl methacrylate monomer and monofunctional unsaturated monomer , 0.5 parts by weight of azobisisobutyronitrile as a polymerization initiator and 0.5 part by weight of a polymerization initiator were added to 100 parts by weight of a monomer mixture comprising (b-1) methyl methacrylate monomer and (b-2) methyl acrylate monomer, And 0.5 part by weight of n-octyl mercaptan as a transfer agent were mixed to prepare a monomer mixture solution. Into a stainless steel high-pressure reactor equipped with a stirrer were charged 130 parts by weight of ion-exchanged water, 0.2 parts by weight of polyethyl acrylate-methyl acrylic acid (weight average molecular weight: 1 million or more) as a suspension stabilizer, And 0.5 parts by weight of disodium hydrogenphosphate, sodium sulfate and the like as a suspension auxiliary stabilizer were added and stirred. The monomer mixture solution was added to an aqueous solution in which the suspension stabilizer and the like were dissolved and stirred. The inside of the reactor was filled with an inert gas such as nitrogen and the mixture was polymerized at 72 ° C for 3 hours and at 110 ° C for 2 hours. Respectively. After the reaction was completed, (meth) acrylic copolymer particles were obtained through washing, dehydration and drying. The physical properties of the particles and the particles obtained by extruding or extruding the particles were measured by the following physical property evaluation method. The results are shown in Table 1.

Comparative Example  One

A monomer mixture composed of 97.5% by weight of methyl methacrylate monomer (b-1) and 2.5% by weight of methyl acrylate monomer (b-2) was used in place of the monomer mixture and 100 parts by weight of the polymerization initiator (Meth) acrylic copolymer was obtained in the same manner as in Example 1, except that 0.3 part by weight of azobisisobutyronitrile (AIBN) and 0.3 part by weight of n-octylmercaptan were mixed. The physical properties of the particles and the particles obtained by extruding or extruding the particles were measured by the following physical property evaluation method. The results are shown in Table 1.

Comparative Example  2-3

(A) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxymethyl methacrylate monomer instead of (c) diethyl (methacryloyl (Meth) acrylate copolymer particles were obtained in the same manner as in Examples 1 and 4 above, except that the (meth) acrylic copolymer particles were used. The physical properties of the particles and the particles obtained by extruding or extruding the particles were measured by the following physical property evaluation method. The results are shown in Table 1.

Method of sample preparation

100 parts by weight of the (meth) acrylic copolymer particles of Example 1-4 and Comparative Example 1-3 and 0.1 part by weight of a hindered phenol heat stabilizer were added and melted, kneaded and extruded to prepare pellets. In this case, a twin-screw extruder having an L / D of 29 and a diameter of 45 mm was used for the extrusion. The pellets were dried at 80 ° C for 6 hours and then injected in a 6 Oz injector to prepare specimens.

Property evaluation method

(1) Weight average molecular weight (Mw): Measured using GPC (Gel Permeation Chromatography) (unit: g / mol).

(2) Refractive index: Measured at 20 DEG C using a "DR-A1" refractometer manufactured by ATAGO, and the thickness of the specimen was 2.5 mm.

(3) Flame retardancy: A specimen having a thickness of 3.2 mm was prepared and the flame retardancy was measured by the UL94 vertical test method. The results are shown in Table 1.

(4) Transparency: A specimen of an injection molded article having a thickness of 2.5 mm was prepared, and the haze (%) and the light transmittance (%) of the appearance of the injection molded article were evaluated. The transmittance (total transmittance, TT) and haze value of the sample were measured using a haze meter NDH 2000 instrument manufactured by Nippon Denshoku Co. The total transmittance was measured by the sum of diffuse transmission light (DF) and parallel transmission light (PT) And the haze value is calculated by the following equation.

At this time, the higher the total transmitted light (TT) and the lower the haze, the better the transparency.

(5) Scratch resistance: Measured by Ball-type Scratch Profile (BSP) test. L90mm x W50mm x t2.5mm A scratch with a length of 10 to 20 mm was applied to the specimen surface with a load of 1000 g and a scratch speed of 75 mm / min using a spherical metal tip of 0.7 mm in diameter. The profile of the applied scratch was surface-scanned with a metal stylus tip having a diameter of 2 탆 using a contact type surface profile analyzer (XP-1) manufactured by Ambios Co., Ltd. to evaluate a scratch width (탆) as a measure of scratch resistance. At this time, the scratch resistance increases as the measured scratch width decreases.

(6) Impact resistance: A notch was made in a 1/8 "Izod specimen by the evaluation method described in ASTM D256, and the impact strength (Izod, unit: kgf · cm / cm) was evaluated.

division Example Comparative Example One 2 3 4 One 2 3 Monomer
mixture (a) 10.0 20.0 20.0 30 - - - (b-1) 87.5 77.5 77.5 67.5 97.5 87.5 67.5 (b-2) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 (c) - - - - - 10.0 30.0 Properties Mw
(× 1000) 40 40 120 120 130 120 120 Refractive index 1.4931 1.4977 1.4977 1.5032 1.4890 1.4844 1.4752 Flammability V2 V1 V1 V0 Fail Fail V2 Haze 1.3% 1.5% 1.4% 1.2% 1.0% 2.3% 3.1% Electric power
Transmittance 91.1% 91.3% 91.4% 91.7% 92.2% 88.3% 87.2% BSP Width 205 215 220 235 180 200 230 Izod
Impact strength 1.9 1.8 2.8 2.7 3.1 2.8 2.7

From the results shown in Table 1, it can be seen that the (meth) acrylic copolymer (Example 1-4) using the phosphorus-based (meth) acrylic monomer having the structure of the present invention has excellent transparency, a high refractive index of 1.4931 or more, Is higher than V2.

On the other hand, Comparative Example 1 in which the phosphorus (meth) acrylic monomer is not used has a disadvantage that the refractive index is 1.490 or less, the scratch resistance is lowered, and the flame retardancy is not possessed. Also, in the case of Comparative Examples 2 and 3 using a conventional phosphorus (meth) acrylic monomer different from the structure of the formula (1) of the present invention, the refractive index was not as high as 1.490 or less, and the transparency and flame retardancy It can be seen that there are disadvantages.

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 (13)

A copolymer of a monomer mixture comprising a phosphorus-based (meth) acrylic monomer represented by the following formula (1) and a monofunctional unsaturated monomer,
Wherein the monofunctional unsaturated monomer comprises alkyl methacrylate having 1 to 8 carbon atoms and alkyl acrylate having 1 to 8 carbon atoms in a weight ratio of 15: 1 to 45: 1.
[Chemical Formula 1]

Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrocarbon group having 1 to 20 carbon atoms, R ₃ and R ₄ are each independently a cyclic hydrocarbon group having 6 to 20 carbon atoms, and m is 1 to 10 And n is an integer of 0 to 5.
The (meth) acrylic copolymer according to claim 1, wherein the content of the phosphorus (meth) acrylic monomer is 1 to 50% by weight, and the content of the monofunctional unsaturated monomer is 50 to 99% by weight.
delete The (meth) acrylic copolymer according to claim 1, wherein the (meth) acrylic copolymer has a weight average molecular weight of 5,000 to 500,000 g / mol.
The (meth) acrylic copolymer according to claim 1, wherein the (meth) acrylic copolymer has a refractive index of 1.490 to 1.590 at a thickness of 2.5 mm.
The (meth) acrylic copolymer according to claim 1, wherein the (meth) acrylic copolymer has a thickness of 3.2 mm and a flame retardancy measured according to UL94 of not less than V2.
The (meth) acrylic copolymer according to claim 1, wherein the (meth) acrylic copolymer is a specimen having a thickness of 2.5 mm and has a total light transmittance of 90% or more as measured according to ASTM D1003.
The composition according to claim 1, wherein the (meth) acrylic copolymer is selected from the group consisting of flame retardants, surfactants, nucleating agents, coupling agents, fillers, plasticizers, impact modifiers, lubricants, antibacterial agents, release agents, heat stabilizers, antioxidants, (Meth) acrylic copolymer, which further comprises at least one of an antistatic agent, an additive, an antistatic agent, a pigment and a dye.
(Meth) acrylic monomer represented by the following formula (1), and a monomer mixture containing a monofunctional unsaturated monomer,
Wherein the monofunctional unsaturated monomer comprises alkyl methacrylate having 1 to 8 carbon atoms and alkyl acrylate having 1 to 8 carbon atoms in a weight ratio of 15: 1 to 45: 1.
[Chemical Formula 1]

Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrocarbon group having 1 to 20 carbon atoms, R ₃ and R ₄ are each independently a cyclic hydrocarbon group having 6 to 20 carbon atoms, and m is 1 to 10 And n is an integer of 0 to 5.
The process for producing a (meth) acrylic copolymer according to claim 9, wherein the polymerization initiator is a radical polymerization initiator, and the polymerization is a suspension polymerization.
The process for producing a (meth) acrylic copolymer according to claim 10, wherein the suspension polymerization is carried out in the presence of a suspension stabilizer and a chain transfer agent.
The composition of claim 9, wherein the monomer is selected from the group consisting of flame retardants, surfactants, nucleating agents, coupling agents, fillers, plasticizers, impact modifiers, lubricants, antibacterial agents, release agents, heat stabilizers, antioxidants, light stabilizers, compatibilizers, Wherein at least one of the pigment and the dye is further added and polymerized to polymerize the (meth) acrylic copolymer.
A molded article formed from the (meth) acrylic copolymer according to any one of claims 1, 2 and 4 to 8.