TWI596120B - (meth)acrylate-styrene based copolymer, composition thereof and molding product thereof - Google Patents

Description

(Meth)acrylate-styrene copolymer and its composition and molded article

The present invention relates to a copolymer, and more particularly to a (meth) acrylate-styrene copolymer, a composition thereof, and a molded article.

Polymethyl methacrylate has good performance in formability, physical properties and mechanical properties. The obtained molded article has good appearance, light transmittance of up to 92%, superior to glass and low refraction, and is currently the most One of the excellent polymer transparent materials. Polymethyl methacrylate, also known as "plexiglass", is often used as a variety of optical components or consumer goods, such as camera lenses, lenses, automotive taillights, billboards, and the like. However, although polymethyl methacrylate has excellent optical properties and process formability, it has high hygroscopicity.

Although polystyrene has good low hygroscopicity and process formability, it is poor in weather resistance, and coloring or mechanical properties are lowered under long-time illumination.

Methyl methacrylate-styrene copolymer obtained by polymerizing styrene and methyl methacrylate as main raw materials, combined with the advantages of polystyrene and polymethyl methacrylate, although partially improved Disadvantages of polymers, however, in recent applications of various optical products (for example, LCD light guide plates), as the size is increased, the optical properties (for example, chromaticity) and hygroscopic properties of the resin molded article are The requirements are more stringent. Based on this, the aforementioned methyl methacrylate-styrene copolymer still cannot meet this requirement.

The present invention provides a (meth) acrylate-styrene copolymer which has the advantages of both polystyrene and polymethyl methacrylate, and has low yellowness and low hygroscopicity, and is therefore suitable for use in It is formed into a copolymer composition of a molded article.

The (meth) acrylate-styrene copolymer of the present invention comprises 10% by weight to 75% by weight of a (meth) acrylate monomer unit, and 25% by weight to 90% by weight of a styrene monomer. The unit wherein the content of pentamer to undepolymer in the (meth) acrylate-styrene copolymer ranges from 500 ppm to 2000 ppm.

In one embodiment of the present invention, the content of the (meth) acrylate monomer unit is in the range of 10% by weight to 60% by weight, and the content of the styrene monomer unit is in the range of 40% by weight to 90% by weight. .

In one embodiment of the present invention, the content of the (meth) acrylate monomer unit is in the range of 10% by weight to 50% by weight, and the content of the styrene monomer unit is in the range of 50% by weight to 90% by weight. .

In one embodiment of the invention, the pentamer to decamer content ranges from 500 ppm to 1800 ppm.

In one embodiment of the invention, the above pentamer to undepolymer is present in an amount ranging from 500 ppm to 1500 ppm.

In one embodiment of the present invention, the content of the dimer to trimer in the (meth) acrylate-styrene copolymer is in the range of 100 ppm to 3000 ppm.

The (meth) acrylate-styrene copolymer composition of the present invention includes the (meth) acrylate-styrene copolymer as described above.

In one embodiment of the present invention, the (meth)acrylate-styrene copolymer composition further includes an antioxidant, and the total weight of the (meth)acrylate-styrene copolymer is 100. The content of the antioxidant ranges from 0.005 parts by weight to 2 parts by weight in parts by weight.

In one embodiment of the present invention, the (meth)acrylate-styrene copolymer composition further includes a slip agent, and the total weight of the (meth)acrylate-styrene copolymer is 100. The content of the slip agent ranges from 0.03 parts by weight to 5 parts by weight.

The molded article of the present invention is formed of the (meth) acrylate-styrene copolymer composition as described above.

Based on the above, the (meth) acrylate-styrene copolymer of the present invention transmits 10% by weight to 75% by weight of (meth) acrylate monomer units and 25% by weight to 90% by weight of styrene. It is a monomer unit and includes a pentamer to an unpolymer in a content ranging from 500 ppm to 2000 ppm, thereby making not only the advantages of polystyrene and polymethyl methacrylate, but also low length. Light path yellow index (YI) value and low moisture absorption.

The above described features and advantages of the present invention will be more apparent from the following description.

In the present specification, the range represented by "a value to another value" is a schematic representation that avoids enumerating all the values in the range in the specification. Therefore, the recitation of a particular range of values is intended to include any value in the range of values and the range of values defined by any value in the range of values, as in the specification. The scope is the same.

Further, herein, (meth)acrylate means acrylate and/or methacrylate. Herein, a monomer unit means a structural unit formed by polymerization of a monomer.

The (meth) acrylate-styrene copolymer according to an embodiment of the present invention includes 10% by weight to 75% by weight of (meth) acrylate type monomer unit, and 25% by weight to 90% by weight Styrene monomer unit. In detail, in the present embodiment, the content of the (meth) acrylate monomer unit ranges from 10% by weight to 75% by weight, that is, the content of the styrene monomer unit ranges from 25 parts by weight. Between % and 90% by weight, the (meth) acrylate-styrene copolymer has low hygroscopicity, whereby the dimensional stability of the subsequently obtained molded article is good; if the content of the styrene monomer unit is The range is between 25% by weight and 90% by weight, that is, the content of the (meth) acrylate monomer unit ranges from 10% by weight to 75% by weight, and the (meth) acrylate-styrene system The long optical path (YI) value of the copolymer is low, whereby the subsequently obtained molded article is less prone to yellowing under long-time illumination.

Further, in one embodiment, the (meth) acrylate-styrene copolymer preferably includes 10% by weight to 60% by weight of the (meth) acrylate monomer unit, and 40% by weight to 90% by weight. The styrene monomer unit of %, more preferably 10% by weight to 50% by weight of the (meth) acrylate monomer unit, and 50% by weight to 90% by weight of the styrene monomer unit.

The (meth) acrylate monomer used for the polymerization of the (meth) acrylate-styrene copolymer includes, for example but not limited to: (1) a methacrylate compound: methyl methacrylate, Ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, octadecyl methacrylate, phenyl methacrylate, benzyl methacrylate or 2-ethyl methacrylate 2-ethylhexyl methacrylate, etc.; (2) acrylate compound: methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate or 2-ethyl acrylate 2-ethylhexyl acrylate and the like. The (meth) acrylate monomer of the present invention is preferably a methacrylate compound.

The styrene-based monomer used for the polymerization of the (meth) acrylate-styrene-based copolymer includes, for example, but not limited to, styrene or a substituted styrene compound. The substituted styrene compound is, for example, (1) a halogen-substituted styrene compound such as chlorostyrene or bromostyrene; (2) vinyl toluene or α-methylstyrene (α-) Methyl styrene) is an alkyl-substituted styrene compound. The styrene-based monomer of the present invention is preferably selected from the group consisting of styrene and α-methylstyrene.

The monomer for polymerizing a (meth) acrylate-styrene copolymer of the present invention does not significantly impair (methyl) except for the above (meth) acrylate monomer and styrene monomer. Within the range of the effect of the acrylate-styrene copolymer, other copolymerizable monomers may be used as needed. Specifically, the total amount of the other copolymerizable monomer may be from 0% by weight to 30% by weight based on 100% by weight of the total of the (meth) acrylate monomer and the styrene monomer. Other copolymerizable monomers include, for example, but not limited to: (1) unsaturated carboxylic acids or anhydrides thereof: acrylic acid, methacrylic acid, maleic acid or itaconic acid, etc.; (2) Malay醯imino compounds: N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, etc.; (3) hydroxyl group-containing (meth) acrylates Compound: monoglyceride or 2-hydroxyethyl (meth)acrylate; (4) other propylene-containing compounds: acrylamide, acrylonitrile ), allyl glycidyl ether or glycidyl (meth)acrylate.

On the other hand, in the present embodiment, the content of the pentamer to the undepolymer in the (meth) acrylate-styrene copolymer is in the range of 500 ppm to 2000 ppm. In detail, in the present embodiment, if the content of the pentamer to the undepolymer is in the range of 500 ppm to 2000 ppm, the YI value of the (meth) acrylate-styrene copolymer is low. The molded article thus obtained is less prone to yellowing under long-time illumination.

Further, in one embodiment, the content of the pentamer to the undepolymer in the (meth) acrylate-styrene copolymer is preferably in the range of 500 ppm to 1800 ppm, more preferably 500 ppm to 1500. Ppm.

In one embodiment, the pentamer includes, for example, M5, M4S1, M3S2, M2S3, M1S4, S5, or a combination thereof, wherein M represents a (meth) acrylate monomer unit and S represents a styrene monomer unit. That is, the pentamer can include a homopentamer, a heteropentamer, or a combination thereof. From another point of view, the pentamer is, for example, a (meth) acrylate-styrene pentamer. Based on the foregoing description, hexamer, heptamer, octamer, 9-mer, decamer, and 11-mer can also be deduced, and thus will not be described again. The dimers and trimers described later are also the same.

It is worth mentioning that, in the present embodiment, the transmission includes 10% by weight to 75% by weight of the (meth) acrylate monomer unit and 25% by weight to 90% by weight of the styrene monomer unit, and The content of the polymer to the undepolymer is in the range of 500 ppm to 2000 ppm, whereby the (meth) acrylate-styrene copolymer not only combines the advantages of polystyrene and polymethyl methacrylate, It has good processability and thermal stability, and also has a lower long light path YI value and low moisture absorption.

Further, in the present embodiment, the content of the dimer to trimer in the (meth) acrylate-styrene copolymer is preferably 3,000 ppm or less. Specifically, in the present embodiment, when the content of the dimer to the trimer is 3,000 ppm or less, the (meth) acrylate-styrene copolymer has low hygroscopicity. In one embodiment, the range of dimer to trimer is more preferably from 100 ppm to 3000 ppm.

Further, in one embodiment, the method for producing a (meth) acrylate-styrene copolymer includes: after preparing a (meth) acrylate-styrene copolymer precursor, Processing method. Specifically, the method for preparing the (meth) acrylate-styrene copolymer precursor is not particularly limited, and a monomer composed of a styrene monomer and a (meth) acrylate monomer can be used. The mixture is carried out by solution copolymerization or bulk copolymerization with a radical initiator, and is preferably carried out by copolymerization in the presence of a solvent. In the monomer mixture, the content of the styrene monomer is from 25% by weight to 90% by weight, preferably from 40% by weight to 90% by weight, more preferably from 50% by weight to 90% by weight, and (methyl The content of the acrylate monomer is from 10% by weight to 75% by weight, preferably from 10% by weight to 60% by weight, more preferably from 10% by weight to 50% by weight.

Further, the radical initiator is not particularly limited, and may be used singly or in combination. Examples of free radical initiators include, but are not limited to: (1) azo compounds: 2,2'-azobis-(isobutyronitrile, AIBN for short), 2 , 2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethyl) (2,2'-azobis-(2,4-dimethyl valeronitrile), abbreviated as ADVN); (2) diacyl peroxide compound: dilauroyl peroxide, Decanoyl peroxide or dibenzoyl peroxide (BPO); (3) dialkyl peroxide compound: 2,5-dimethyl-2,5- 2,5-dimethyl-2,5-di-(t-butyl peroxy)hexane, dicumyl peroxide or 1,3-double (1,3-bis-(t-butyl peroxy isopropyl)benzene, etc.; (4) Peroxyester compound: tertiary butyl peroxidation T-butyl peroxypivalate or 2,5-dimethyl-2,5-di(2-ethylhexyl) (2,5-dimethyl-2,5-di(2-ethyl hexanoyl peroxy)hexane); (5) peroxycarbonate compound: 2-ethylhexyl tertiary Tert-amyl peroxy 2-ethylhexyl carbonate or tert-butyl peroxy 2-ethylhexyl carbonate; (6) peroxydicarbonate (peroxydicarbonate) compound: dimyristyl peroxydicarbonate or di(4-tert-butyl cyclohexyl) peroxydicarbonate; (7) Peroxyketal compounds: 1,1-di(tertiary butyl peroxy)-3,3,5-trimethylcyclohexane (1,1-di(tert-butyl) Peroxy)-3,3,5-trimethyl cyclohexane) or 2,2-di(4,4-di(tri-butylperoxy)cyclohexyl)propane (2,2-di(4,4-di(tert) -butyl peroxy)cyclohexyl)propane); (8) Hydroperoxide compounds: t-butyl hydroperoxide or isopropyl cumyl hydroperoxide (isopropy) l cumyl hydroperoxide); (9) Others: 2,3-dimethyl-2,3-diphenyl butane. The radical initiator is used in an amount ranging from 0.01 part by weight to 1 part by weight, preferably from 0.01 part by weight to 0.5 part by weight, more preferably 0.01% by weight based on 100% by weight based on the total mass of the monomer mixture fed. Parts to 0.1 parts by weight.

Further, the reactor used for the foregoing reaction may be a fully mixed continuous reactor (CSTR), a laminar flow reactor, a plug flow reactor (PFR) or a static hybrid reactor (static One of the mixing reactors or a combination of different kinds. Further, the above reaction can be carried out at normal temperature, and the reaction system can be heated to increase the rate of polymerization. Specifically, the reaction temperature may range from 25 ° C to 200 ° C, preferably from 50 ° C to 180 ° C; the reaction operation time may range from 6 hours to 10 hours; and the reaction pressure may range from 400 torr to 800 torr .

Further, the boiling point of the solvent is preferably similar to the boiling point of the main monomer used for the polymerization reaction, for example, a solvent having a boiling point close to the boiling point of the (meth) acrylate monomer or the styrene monomer, and the solvent is as described above. The mixture formed by the monomer has a narrow boiling point range, which reduces the chance of the mixture mixing with contaminants during recycle, eliminating the need for intermediate fractionation of the mixture. Specifically, the solvent may be a hydrocarbon solvent or an aromatic hydrocarbon solvent having a boiling point ranging from 40 ° C to 225 ° C, preferably from 60 ° C to 180 ° C, and examples thereof include, but are not limited to, hexane , heptane, octane, benzene, toluene, p-xylene, o-xylene, m-xylene, ethylbenzene, cyclohexane, cyclodecane or isooctane, and can be used singly or in combination.

The post-treatment method of the (meth)acrylate-styrene copolymer precursor is not particularly limited, and for example, a solvent treatment method can be used. The solvent treatment method is to control the oligomerization in the (meth) acrylate-styrene copolymer precursor by using different solubility characteristics of the (meth) acrylate-styrene copolymer precursor by different solvents. The (meth) acrylate-styrene copolymer of the present invention was obtained in terms of the content. Specifically, the solvent treatment method includes the following steps: First, the solvent mixture is formulated according to the required solubility, wherein the solvent mixture includes: a solvent having good solubility to the (meth) acrylate-styrene copolymer precursor And a solvent having poor solubility to the (meth) acrylate-styrene copolymer precursor. Solvents having good solubility for the (meth) acrylate-styrene copolymer precursor include, but are not limited to, hexane, heptane, octane, benzene, toluene, chloroform, p-xylene, o-xylene, M-xylene, ethylbenzene, cyclohexane, tetrahydrofuran, cyclodecane or isooctane; and solvents having poor solubility to (meth)acrylate-styrene copolymer precursors include, but are not limited to: acetone , dimethylformamide, methanol, ethanol, cyclohexanone, dimethylacetamide, dimethylhydrazine or 1,4-dioxane. Specifically, the kind and content of the solvent included in the solvent mixture are not particularly limited as long as the desired solubility can be achieved.

Next, the solvent mixture is mixed with the (meth) acrylate-styrene copolymer precursor. In detail, in this step, since the solvent mixture produces a specific solubility to the (meth) acrylate-styrene copolymer precursor, the insoluble portion will precipitate.

Thereafter, the portion precipitated in the previous step is taken out, and the portion is subjected to a devolatilization step via a devolatilizer. In detail, the devolatilization device is, for example, a devolatilization tank with a vacuuming device. The devolatilization tank may be used in one or several series, and the temperature of the devolatilization tank is controlled at 210 ° C to 280 ° C, preferably 220 ° C to 270 ° C, and the vacuum degree of the devolatilization tank is controlled at 100. Below torr, it is preferably 30 torr or less. In addition, the devolatilization device may also be, for example, a uniaxial or biaxial extruder with a devolatilization, a thin film evaporator or the like, and other suitable devolatilizers.

It is worth mentioning that, in the solvent treatment mode, the number of times of performing the above three-step procedure is not particularly limited as long as it is possible to obtain 10% by weight to 75% by weight of (meth) acrylate monomer units and 25% by weight. It is sufficient to use 90% by weight of the styrene monomer unit and the content of the pentamer to the undepolymer in the range of 500 ppm to 2000 ppm of the (meth) acrylate-styrene copolymer.

Further, although the above embodiment discloses that a (meth) acrylate-styrene copolymer is prepared by subjecting a (meth) acrylate-styrene copolymer precursor to a solvent treatment, the present invention is not limited thereto. this. In another embodiment, the purpose of preparing a (meth) acrylate-styrene copolymer can also be achieved by a method such as a polymerization process, equipment control, enhanced devolatilization, devolatilization, or a combination thereof.

The (meth) acrylate-styrene copolymer composition according to another embodiment of the present invention includes the (meth) acrylate-styrene copolymer in any of the above embodiments. The description of the (meth) acrylate-styrene copolymer has been described in detail in the above embodiments, and thus will not be described again.

In the present embodiment, the (meth) acrylate-styrene copolymer composition can be selectively added in the range of the effect of not significantly impairing the (meth) acrylate-styrene copolymer. An additive, such as, but not limited to, an antioxidant, a slip agent, a processing aid, an ultraviolet absorber, an ultraviolet stabilizer, a charge preventive agent, a filler, a strengthening agent, a colorant, a heat stabilizer, a thermochromic preventive agent, Light diffusing agent, plasticizer, flame retardant, flame retardant, coupling agent or other additives. Further, the timing of the addition of the additive is not particularly limited, and the additive may be added before the polymerization reaction, during the polymerization reaction, or after the polymerization reaction, depending on the actual process.

The antioxidant may be used singly or in combination, and includes, but is not limited to, a phenolic antioxidant, a thioether antioxidant, or a phosphorus antioxidant. The antioxidant is contained in an amount ranging from 0.005 parts by weight to 2 parts by weight based on 100 parts by weight of the total of the (meth) acrylate-styrene copolymer.

Examples of phenolic antioxidants include, but are not limited to, 3-(3,5-ditributyl-4-hydroxyphenyl)propanoic acid n-octadecyl ester, triethylene glycol-bis[3- (3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], tetrakis[methylene-3-(3,5-bis-tertiary butyl-4-hydroxyphenyl) Propionate] methane, 2-tris-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2,2'- Methylene-bis(4-methyl-6-tertiary butyl phenol), 2,2'-thiobis(4-methyl-6-tertiary butyl phenol), 2,2'-thio- Diethylene-bis[3-(3,5-bistris-butyl-4-hydroxyphenyl)propionate] or 2,2'-ethylenediamine-bis[ethyl-3-(3) , 5-bis-tris-butyl-4-hydroxyphenyl)propionate] and the like.

Examples of thioether-based antioxidants include, but are not limited to, distearyl thiodipropionate, dipalmitothio dipropionate, pentaerythritol-tetrakis-(β-dodecyl-thiopropyl) Acid ester) or dioctadecyl sulfide.

Phosphorus-based antioxidants include, but are not limited to, phosphorous acids, phosphoric acids, phosphinic acids, phosphonic acids, phosphites, phosphates, phosphonites, phosphonates, tertiary phosphines, A compound of a triorganophosphate or an acid phosphate. Among the above phosphorus-based antioxidants, a compound of a phosphorous acid, a phosphoric acid, a phosphinic acid, a phosphonic acid, a triorganophosphoric acid ester or an acidic phosphate ester is particularly preferable. Further, in the acidic phosphate compound, the organic group may include a mono-, di- or poly-substitution. The compounds exemplified below may be used singly or in combination.

Examples of triorganophosphate compounds include, but are not limited to, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tridecyl phosphate, tridodecyl Phosphate, trilauryl phosphate, tristearyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, diphenyl cresyl phosphate, diphenyl mono-- Biphenyl phosphate or tris(butoxyethyl) phosphate. Preferably, the triorganophosphate compound is a trialkyl phosphate compound; more preferably, the alkyl group in the trialkyl phosphate compound has a carbon number of 1 to 22; more preferably, The alkyl group in the trialkyl phosphate compound has a carbon number of 1 to 4. In one embodiment, the trialkyl phosphate compound is trimethyl phosphate.

Examples of acidic phosphate compounds include, but are not limited to, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, butoxy ethyl acid phosphate, octyl acid phosphate, thiol acid Phosphate ester, lauryl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonylphenyl acid phosphate, cyclohexyl acid phosphate , phenoxyethyl acid phosphate, alkoxy polyethylene glycol acid phosphate or bisphenol A acid phosphate. Among the above acidic phosphate compounds, a long-chain dialkyl acid phosphate having a carbon number of 10 or more can effectively improve the (meth) acrylate-styrene copolymer composition in addition to high thermal stability. Thermal stability.

Examples of phosphite compounds include, but are not limited to, triphenyl phosphite, tris(nonylphenyl) phosphite, tridecyl phosphite, trioctyl phosphite, three (eighteen Alkyl) phosphite, dimethylphenyl phosphite, dioctylphenyl phosphite, diisopropylphenyl phosphite, butyl diphenyl phosphite, decyl diphenyl Phosphate ester, octyl diphenyl phosphite, tris(diethylphenyl) phosphite, tris(diisopropylphenyl) phosphite, tris(di-n-butylphenyl) phosphite, Tris(2,4-ditributylphenyl)phosphite, tris(2,6-ditributylphenyl)phosphite, distearyl pentaerythritol diphosphite, double (2,4-ditributylphenyl) pentaerythritol diphosphite, bis(2,6-ditributyl-4-methylphenyl)neopentanol diphosphite, Bis(2,6-ditributyl-4-ethylphenyl)neopentitol diphosphite, bis{2,4-bis(1-methyl-1-phenylethyl)phenyl } Pentaerythritol diphosphite, phenyl bisphenol A neopentyl alcohol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite or dicyclohexyl neo Tetraols diphosphite.

The slip agent can be used singly or in combination, and includes but is not limited to: (1) metal soap: calcium stearate, magnesium stearate or lithium stearate; (2) compound: ethylene distearin Amine (ethylene bis (stearamide), referred to as EBS), methylene distearylamine, decyl palmitate, butyl stearate, palmitate stearate, polypropionate tristearate, pentaerythritol stearin Acid ester, n-docosanoic acid, stearic acid or stearyl alcohol; (3) wax: polyethylene wax, octadecanoic acid wax, carnauba wax or petroleum wax; (4) Higher alcohols: stearyl alcohol and the like. The total amount of the (meth) acrylate-styrene copolymer is 100 parts by weight, and the content of the lubricant is in the range of 0.03 part by weight to 5 parts by weight.

The processing aid can improve extrusion moldability and thermoformability, and can use, for example, an acrylate-based processing aid or a core-shell type processing aid having a weight average molecular weight of 500,000 or more. The above processing aids can be used singly or in combination.

The ultraviolet absorber can be used singly or in combination, and includes, but is not limited to, a benzotriazole-based compound, a benzophenone-based compound, a cyanoacrylic acid-based compound, and the like.

The ultraviolet stabilizer can be used singly or in combination, and includes, but is not limited to, a hindered amine compound or the like.

The content of the processing aid, the ultraviolet absorber, and the ultraviolet stabilizer is 0.02 to 2.0 parts by weight, respectively, based on 100 parts by weight of the total of the (meth) acrylate-styrene copolymer.

The charge preventing agent can be used singly or in combination, and includes, but is not limited to, a low molecular weight compound such as a tertiary amine compound or a quaternary ammonium salt compound, or a polymer having a permanent charge prevention property such as polyamine polyether. class.

The fillers can be used singly or in combination, and include, but are not limited to, calcium carbonate, alumina, mica, and the like.

The enhancer can be used singly or in combination, and includes, but is not limited to, glass fibers, carbon fibers, various whiskers, and the like.

The colorant can be used singly or in combination, and includes, but is not limited to, titanium oxide, iron oxide, graphite, phthalocyanine dye, and the like.

The light diffusing agent can be used singly or in combination, and includes but not limited to: (1) inorganic diffusing agent: alumina, cerium oxide, magnesium oxide, iron oxide, titanium oxide, zinc oxide, tin oxide, cerium nitride, nitrogen. Inorganic particles such as aluminum, barium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, calcium citrate, aluminum citrate, zirconium silicate or potassium titanate; (2) organic diffusing agent: epoxy resin, melamine resin, Resins such as urea-based resin, (meth)acrylate-based resin, polyorganosiloxane-based resin, phenolic resin, polyimide-based resin, polyamine-based resin, polyester resin, or Teflon resin particle.

It is worth mentioning that, as mentioned above, the (meth) acrylate-styrene copolymer not only has good processability and thermal stability, but also has a low YI value and low hygroscopicity, thereby The methyl acrylate-styrene copolymer composition also has good processability, thermal stability, low YI value, and low moisture absorption. As described above, the (meth) acrylate-styrene copolymer composition of the present embodiment can be suitably used for the preparation of a molded article, and can be blended with the additive to conform to the properties required for the subsequent preparation of the molded article.

A molded article according to still another embodiment of the present invention is formed from the (meth) acrylate-styrene copolymer composition of any of the above embodiments. The description of the (meth) acrylate-styrene copolymer composition has been described in detail in the above embodiments, and thus will not be described again.

The molded article may be various molded articles obtained by injection molding, compression molding, or various molded articles obtained by extrusion molding, blow molding, thermoforming, vacuum molding, or hollow molding. Specifically, examples of the molded article include, but are not limited to, optical grade sheets (for example, light guide plates, diffusion sheets, and the like), film molded articles, and the like.

It is worth mentioning that, as described above, the (meth) acrylate-styrene copolymer composition of the present invention has a low YI value and low hygroscopicity, whereby the (meth) acrylate system is used. The molded article obtained by the styrene copolymer composition is less prone to yellowing under long-time illumination, and is less susceptible to structural deformation by moisture and moisture. As a result, the molded article of the present embodiment is excellent in service life, storage stability, and dimensional stability, and is particularly suitable as an optical grade sheet.

The features of the present invention will be more specifically described below with reference to Examples 1 to 9 and Comparative Examples 1 to 9. Although the following Examples 1 to 9 are described, the materials used, the amounts and ratios thereof, the processing details, the processing flow, and the like can be appropriately changed without departing from the scope of the present invention. Therefore, the invention should not be construed restrictively by the examples described below. Preparation of styrene-based copolymer composition precursor - Synthesis Examples 1 to 11 comprising a (meth) acrylate

The polymerization apparatus for preparing the composition containing the (meth) acrylate-styrene copolymer precursor of Synthesis Examples 1 to 11 includes a completely mixed reactor, a laminar flow reactor, and a devolatilizer. In order to clearly illustrate the preparation process, the following is described in Synthesis Example 1, and the remaining synthesis examples were prepared in the same manner.

According to the kind and amount of each component listed in Table 1, each component is continuously fed into the fully mixed reactor for continuous solution polymerization, wherein the reaction temperature is maintained at 100 ° C and the pressure is 600 torr. . Each component was thoroughly stirred and mixed in a completely mixed reactor to form a reactant, and after standing for about 3.5 hours, the reactant was continuously fed into the laminar flow reactor. In the laminar flow reactor, a polymer solution was formed after about 5 hours of residence. Next, the polymer solution is sent to the devolatilizer, and the polymer solution is heated to 235 ° C, and then subjected to a devolatilization step under a reduced pressure atmosphere to obtain the inclusion of Synthesis Example 1 ( A composition of a methyl acrylate-styrene copolymer precursor.

Further, a (parts by weight) in Table 1 is 100 parts by weight based on the total weight of the monomer mixture; b (parts by weight) is 100 based on the total weight of the (meth) acrylate-styrene copolymer Parts by weight. Table 1 <TABLE border="1"borderColor="#000000"width="85%"><TBODY><tr><td></td><td> Synthesis example</td></tr><tr ><td> 1 </td><td> 2 </td><td> 3 </td><td> 4 </td><td> 5 </td><td> 6 </td><Td> 7 </td><td> 8 </td><td> 9 </td><td> 10 </td><td> 11 </td></tr><tr><td> Body mixture</td><td> styrene monomer (parts by weight)^a</td><td>styrene</td><td> 89 </td><td> 80 </td><td> 70 </td><td> 60 </td><td> 55 </td><td> 50 </td><td> 40 </td><td> 30 </td><td> 26 </td><td> 20 </td><td> 95 </td></tr><tr><td> (meth)acrylate monomer (parts by weight) ^a</td><td> Methyl methacrylate</td><td> 11 </td><td> 20 </td><td> 30 </td><td > 40 </td><td> 45 </td><td> 50 </td><td> 60 </td><td> 70 </td><td> 74 </td><td> 80 </td><td> 5 </td></tr><tr><td> Solvent (parts by weight)^a</td><td>Ethylbenzene</td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td><td> 10 </td></tr><tr><td> Free radical initiation Agent (parts by weight)^a</td><Td>1,1-di(tri-butylperoxy)-3,3,5-trimethylcyclohexane</td><td> 0.03 </td><td> 0.03 </td><td > 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td></tr><tr><td> slip agent (parts by weight)^b</td><td > octadecyl alcohol</td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td><td > 0.05 </td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td><td> 0.05 </td></tr><tr><td> Antioxidant (parts by weight)^b</td><td> 3-(3,5-ditributyl-4-hydroxyphenyl)propanoic acid Octadecanol ester</td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td > 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td><td> 0.03 </td></tr></TBODY></TABLE> Example 1 Preparation of ( meth ) acrylate - styrene copolymer composition

100 parts by weight of the composition containing the (meth) acrylate-styrene copolymer precursor of Synthesis Example 1 was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 600 parts by weight of acetone, and stirred. well mixed. Next, a portion which was not dissolved in the solvent mixture and precipitated was taken out by filtration. Thereafter, the taken-out portion was sent to a devolatilizer, heated to 235 ° C, and subjected to a devolatilization step under a reduced pressure atmosphere (30 torr) to obtain the (meth)acrylic acid of Example 1. An ester-styrene copolymer composition. Example 2 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 2 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 2 was 100 parts by weight of the synthesis of Synthesis Example 2 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of cyclohexane and 500 parts by weight of methanol. Example 3 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 3 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 3 was 100 parts by weight of Synthesis Example 3 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of toluene and 500 parts by weight of dimethylformamide. Example 4 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 4 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 4 was 100 parts by weight of the synthesis of Synthesis Example 4 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of octane and 400 parts by weight of dimethyl hydrazine. Example 5 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 5 was prepared in accordance with a preparation procedure similar to that of Example 1, and the difference was mainly in that Example 5 was carried out using 100 parts by weight of the synthesis of Synthesis Example 5 ( The composition of the methyl acrylate-styrene copolymer precursor is subjected to two solvent treatment methods, wherein the first solvent treatment method uses a solvent mixture composed of 100 parts by weight of ethylbenzene and 300 parts by weight of acetone. A second solvent treatment method uses a solvent mixture composed of 100 parts by weight of cyclohexane and 400 parts by weight of methanol. Example 6 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 6 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 6 was 100 parts by weight of the synthesis of Synthesis Example 6 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 450 parts by weight of acetone. Preparation of styrene-based copolymer composition - Example 7 (meth) acrylate-based embodiment

The (meth) acrylate-styrene copolymer composition of Example 7 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 7 was 100 parts by weight of the synthesis of Synthesis Example 7 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 450 parts by weight of acetone. Example 8 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 8 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 8 was 100 parts by weight of the synthesis of Synthesis Example 8 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 500 parts by weight of acetone. Example 9 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Example 9 was prepared according to a preparation procedure similar to that of Example 1, and the difference was mainly that Example 9 was 100 parts by weight of the synthesis of Synthesis Example 9 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 550 parts by weight of acetone. Comparative Example 1 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Comparative Example 1 was prepared according to a preparation procedure similar to that of Example 1, except that Comparative Example 1 was used in 100 parts by weight of Synthesis Example 1 ( The composition of the methyl acrylate-styrene copolymer precursor is subjected to four solvent treatment methods, wherein the first solvent treatment method uses a solvent mixture composed of 100 parts by weight of ethylbenzene and 350 parts by weight of acetone. The second solvent treatment method uses a solvent mixture composed of 100 parts by weight of cyclohexane and 300 parts by weight of methanol, and a third solvent treatment method using 100 parts by weight of toluene and 400 parts by weight of dimethylformamidine. A solvent mixture composed of an amine and a fourth solvent treatment method used a solvent mixture composed of 100 parts by weight of octane and 400 parts by weight of dimethylarylene. Comparative Example 2 Preparation of ( meth ) acrylate - styrene copolymer composition

The (meth) acrylate-styrene copolymer composition of Comparative Example 2 was prepared in accordance with a preparation procedure similar to that of Example 1, except that Comparative Example 2 was obtained by combining 100 parts by weight of Synthesis Example 10 ( The composition of the methyl acrylate-styrene copolymer precursor was added to a solvent mixture composed of 100 parts by weight of ethylbenzene and 550 parts by weight of acetone. Comparative example 3

100 parts by weight of the composition containing the (meth) acrylate-styrene copolymer precursor of Synthesis Example 5 was directly placed in a vacuum oven, and was carried out under the conditions of a vacuum of 1000 Pa and a temperature of 250 ° C. After the treatment for 1 hour, the (meth) acrylate-styrene copolymer composition of Comparative Example 3 was obtained. Comparative example 4

The (meth) acrylate-styrene copolymer composition of Comparative Example 4 was a composition containing a (meth) acrylate-styrene copolymer precursor of Synthesis Example 1 without any treatment. . Comparative Example 5

The (meth) acrylate-styrene copolymer composition of Comparative Example 5 is a composition containing a (meth) acrylate-styrene copolymer precursor of Synthesis Example 9 which was used without any treatment. . Comparative Example 6

The (meth) acrylate-styrene copolymer composition of Comparative Example 6 was a composition containing a (meth) acrylate-styrene copolymer precursor of Synthesis Example 10 without any treatment. . Comparative Example 7

The (meth) acrylate-styrene copolymer composition of Comparative Example 7 was a composition containing a (meth) acrylate-styrene copolymer precursor of Synthesis Example 11 which was used without any treatment. . Comparative Example 8

Unlike Examples 1 to 9 and Comparative Examples 1 to 7, Comparative Example 8 did not directly prepare a (meth)acrylate-styrene copolymer composition, but directly used a commercially available product TX-800LF (purchased) Since the electric chemical company). Comparative Example 9

Unlike Examples 1 to 9 and Comparative Examples 1 to 7, Comparative Example 9 was not a self-prepared (meth)acrylate-styrene copolymer composition, but was directly used as a commercially available product MS-500 (purchased) Since the Nippon Steel Corporation).

Thereafter, the (meth) acrylate-styrene copolymer composition of Examples 1 to 9 and Comparative Examples 1 to 9 was subjected to a monomer unit of a (meth) acrylate-styrene copolymer. The content was measured, the content of the oligomer in the (meth) acrylate-styrene copolymer was measured, the yellow index (YI) was measured, and the hygroscopicity was measured. The descriptions and evaluation criteria of the above respective measurements are as follows, and the results of the measurements and the evaluation results are shown in Table 2. <Content Determination of Monomer Units>

First, the (meth)acrylate-styrene copolymer compositions of Examples 1 to 9 and Comparative Examples 1 to 9 were respectively measured by nuclear magnetic resonance (NMR) analysis to obtain nuclear magnetic resonance. Hydrogen spectrum. Next, the content of the (meth) acrylate monomer unit and the styrene monomer unit was calculated from the area ratio of the specific peak in the nuclear magnetic resonance spectrum. The (% by weight) in Table 2 is based on the total weight of the (meth) acrylate-styrene copolymer. <Measurement of oligomer content>

A gas chromatograph (manufactured by Agilent Co.; No. 7890) having a flame ionization detector (FID) and a liquid chromatography mass spectrometer (manufactured by Agilent Co., Ltd.; No. G2246A) were respectively used for Example 1 The composition of the (meth) acrylate-styrene copolymer of ~9 and Comparative Examples 1 to 9 was analyzed and quantified. (ppm) in Table 2 is based on the total weight of the (meth) acrylate-styrene copolymer. < Measurement of Yellowness (YI) of Changguang Road >

The (meth)acrylate-styrene copolymer compositions of Examples 1 to 9 and Comparative Examples 1 to 9 were each formed into a test piece having a size of 220 mm × 20 mm × 3 mm, and then split by a long light path. The test piece was subjected to measurement of the YI value by a color meter (manufactured by Nippon Denshoku Industries Co., Ltd.; model: NIPPON DENSHOKU ASA-1). The evaluation criteria are as follows: ○..YI <5.50; △..5.50 ≦ YI <7.50; ×..YI ≧ 7.50. <Measurement of hygroscopicity>

The test pieces obtained by performing the YI measurement were weighed separately to obtain a weight value W1. Next, the test pieces were left to stand in water at 60 ° C for 24 hours, and then taken out and dried with a dust-free cloth. Then, the test pieces were weighed again to obtain a weight value W2. The hygroscopicity was obtained by the following formula, and the evaluation criteria were as follows: Hygroscopicity (%) = [(W2-W1) / (W1)] × 100% ○: hygroscopicity < 1.5%; △: 1.5% ≦ hygroscopicity <5%; ×: hygroscopicity ≧ 5%. Table 2         <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> Example</td></tr><tr>< Td> 1 </td><td> 2 </td><td> 3 </td><td> 4 </td><td> 5 </td><td> 6 </td><td> 7 </td><td> 8 </td><td> 9 </td></tr><tr><td> Styrene monomer unit (% by weight) </td><td> 89 < /td><td> 80 </td><td> 70 </td><td> 60 </td><td> 55 </td><td> 50 </td><td> 40 </td ><td> 30 </td><td> 26 </td></tr><tr><td> (meth)acrylate monomer unit (% by weight) </td><td> 11 < /td><td> 20 </td><td> 30 </td><td> 40 </td><td> 45 </td><td> 50 </td><td> 60 </td ><td> 70 </td><td> 74 </td></tr><tr><td> pentamer to elevenmer (ppm) </td><td> 1945 </td> <td> 1750 </td><td> 1320 </td><td> 1098 </td><td> 568 </td><td> 1237 </td><td> 1264 </td><td > 1563 </td><td> 1885 </td></tr><tr><td> Dimer to trimer (ppm) </td><td> 2687 </td><td> 2568 </td><td> 2455 </td><td> 2306 </td><td> 1253 </td><td> 2387 </td><td> 2478 </td><td> 2345 </ Td><td> 2553 </td></tr><tr><td> Long light path yellowness</td><td> ○ </td><td> ○ </td><td> </td><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </ Td></tr><tr><td> hygroscopicity</td><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </td ><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </td><td> ○ </td></tr></TBODY>< /TABLE>Table 2 (continued)         <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> Comparative example</td></tr><tr>< Td> 1 </td><td> 2 </td><td> 3 </td><td> 4 </td><td> 5 </td><td> 6 </td><td> 7 </td><td> 8 </td><td> 9 </td></tr><tr><td> Styrene monomer unit (% by weight) </td><td> 89 < /td><td> 20 </td><td> 55 </td><td> 89 </td><td> 26 </td><td> 20 </td><td> 95 </td ><td> 56 </td><td> 52 </td></tr><tr><td> (meth)acrylate monomer unit (% by weight) </td><td> 11 < /td><td> 80 </td><td> 45 </td><td> 11 </td><td> 74 </td><td> 80 </td><td> 5 </td ><td> 44 </td><td> 48 </td></tr><tr><td> pentamer to eleven (ppm) </td><td> 352 </td> <td> 1978 </td><td> 2285 </td><td> 5911 </td><td> 2290 </td><td> 2351 </td><td> 6358 </td><td > 2180 </td><td> 4174 </td></tr><tr><td> Dimer to trimer (ppm) </td><td> 1625 </td><td> 2857 </td><td> 150 </td><td> 8671 </td><td> 3297 </td><td> 3133 </td><td> 8963 </td><td> 5592 </ Td><td> 10435 </td></tr><tr><td> Long light path yellowness</td><td> △ </td><td> ○ </td><td> × </td><td> × </td><td> × </td><td> × </td><td> × </td><td> × </td><td> × </ Td></tr><tr><td> hygroscopicity</td><td> ○ </td><td> × </td><td> ○ </td><td> △ </td ><td> △ </td><td> × </td><td> △ </td><td> △ </td><td> × </td></tr></TBODY>< /TABLE>

As is apparent from the above Table 2, the (meth) acrylate-styrene copolymer compositions of Examples 1 to 9 were excellent in yellowness and hygroscopicity in the long light path. This result confirmed that the pass includes 10% by weight to 75% by weight of the (meth) acrylate monomer unit and 25% by weight to 90% by weight of the styrene monomer unit, and the pentamer to the undepolymerized The content ranges from 500 ppm to 2000 ppm, whereby the (meth) acrylate-styrene copolymer composition can have both a low YI value and a low hygroscopicity.

Further, as is clear from the above Table 2, the content of the dimer to trimer in the (meth) acrylate-styrene copolymer composition of Examples 1 to 9 was 3,000 ppm or less.

Further, as is clear from the above Table 2, the content of the pentamer to the undepolymer in the (meth)acrylate-styrene copolymer composition of Comparative Example 1 was much lower than 500 ppm, and the YI value was high.

Further, as apparent from the above Table 2, although the content of the pentamer to the undepolymer in the (meth) acrylate-styrene copolymer composition of Comparative Example 2 was in the range of 500 ppm to 2000 ppm, However, since the content of the (meth) acrylate-based monomer unit is more than 75% by weight, the (meth) acrylate-styrene-based copolymer composition has poor hygroscopicity.

Further, as apparent from the above Table 2, the (meth) acrylate-styrene copolymer composition of Comparative Example 3 which was subjected to vacuum heat treatment during the preparation to adjust the oligomer content, although dimer to trimer thereof The content of the body is low, but the content of pentamer to decamer is still higher than 2000 ppm, which makes the YI value high.

The present invention has been disclosed in the above embodiments, but it is not intended to limit the invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

no.

no.

Claims (10)

A (meth) acrylate-styrene copolymer comprising: 10% by weight to 75% by weight of a (meth) acrylate monomer unit; and 25% by weight to 90% by weight of a styrene monomer The unit wherein the content of pentamer to undepolymer in the (meth) acrylate-styrene copolymer ranges from 500 ppm to 2000 ppm. The (meth) acrylate-styrene copolymer according to claim 1, wherein the (meth) acrylate monomer unit is contained in an amount ranging from 10% by weight to 60% by weight. The content of the styrene monomer unit ranges from 40% by weight to 90% by weight. The (meth) acrylate-styrene copolymer according to claim 1, wherein the (meth) acrylate monomer unit is contained in an amount ranging from 10% by weight to 50% by weight. The content of the styrene monomer unit ranges from 50% by weight to 90% by weight. The (meth) acrylate-styrene copolymer according to claim 1, wherein the pentamer to the undepolymerized content is in the range of 500 ppm to 1800 ppm. The (meth) acrylate-styrene copolymer according to claim 1, wherein the pentamer to the undepolymerized content is in the range of 500 ppm to 1500 ppm. The (meth) acrylate-styrene copolymer according to claim 1, wherein the (meth) acrylate-styrene copolymer is a dimer to a trimer. The content ranges from 100 ppm to 3000 ppm. A (meth) acrylate-styrene copolymer composition, which comprises the (meth) acrylate-styrene copolymer according to any one of claims 1 to 6. The (meth) acrylate-styrene copolymer composition according to claim 7, further comprising an antioxidant, and the total of the (meth) acrylate-styrene copolymer The weight is 100 parts by weight, and the antioxidant is contained in an amount ranging from 0.005 parts by weight to 2 parts by weight. The (meth) acrylate-styrene copolymer composition according to claim 7, further comprising a lubricant, and the total of the (meth) acrylate-styrene copolymer The weight of the slip agent ranges from 0.03 parts by weight to 5 parts by weight, based on 100 parts by weight. A molded article formed of the (meth) acrylate-styrene copolymer composition according to any one of claims 7 to 9.