KR101202053B1 - Method for preparing heat resistant transparent styrene-based resin with high chemical resistance and moisture resistance - Google Patents

Abstract

The present invention provides a method for producing a styrene resin comprising a styrene repeating unit, a (meth) acrylic acid repeating unit, and a cycloalkyl (meth) acrylate repeating unit. According to the present invention, while maintaining properties such as heat resistance, transparency and processability, the chemical resistance and hygroscopicity are remarkably improved to provide a heat-resistant transparent styrene resin suitable for use in optical or display materials.

Styrene-based resin, block polymerization method, chemical resistance, hygroscopicity

Description

METHOD FOR PREPARING HEAT RESISTANT TRANSPARENT STYRENE-BASED RESIN WITH HIGH CHEMICAL RESISTANCE AND MOISTURE RESISTANCE}

The present invention relates to a method for producing a heat-resistant transparent styrene resin suitable for use in optical or display materials by significantly improving chemical resistance and hygroscopicity without impairing properties such as heat resistance, transparency and processability.

Copolymers of styrene-based monomers and methacrylate-based monomers have excellent balance of transparency, processability, and mechanical properties, and are inexpensive than polycarbonate resins and thus belong to one of the most widely used transparent resins.

However, its use has been limited in display materials such as light guide plates and diffusion plates, and materials requiring particularly heat resistance such as lighting devices and optical lenses.

As a method for imparting heat resistance to such copolymers, US Pat. Nos. 4,558,098 and 6,916,951 disclose methods for copolymerizing methyl methacrylate, styrene or alpha methylstyrene, and maleic anhydride.

The method has an effect of increasing the glass transition temperature and the heat distortion temperature, but there is a problem in that discoloration due to heat can easily occur to reduce transparency, and is limited to the composition ratio of a constant methyl methacrylate and styrene.

Japanese Laid-Open Patent Publication No. 2002-328240 discloses a method of copolymerizing methyl methacrylate, styrene or alpha methyl styrene, and maleimide.

However, the method has a difficulty in dealing with the solid raw materials, there is a problem in color.

In addition, Japanese Laid-Open Patent Publication No. 2006-137911 discloses a method for producing a copolymer of styrene, methyl methacrylate and methacrylic acid.

However, the copolymer is poor in workability, and since the foam sheet is prepared by adding a foam, a plasticizer, etc. during post-processing, and used as a food container, there is a problem in that it is limited to use as an optical transparent material. In addition, when copolymerizing methacrylic acid there is a problem in that the appearance physical properties are lowered by forming an insoluble gel by heat in the volatilization process for recovering the unreacted monomer.

Therefore, US Patent 4,195, 169 has proposed a method of adding water, alcohol-based additives, etc. to the volatilizer in order to inhibit the gel formation after copolymerizing methacrylic acid.

However, in order to add water or alcoholic additives to the gasoline, there is a constraint that a separate device must be installed.

In addition, U.S. Patent 4,937,298 said that several reactors were connected in series, and branching of methacrylic acid and polymerization inhibitor into each reactor improved the surface of the injection molding, but this fundamentally solved the problem of gel formation in the volatilizer. It is hard to see.

In order to solve this problem, it was possible to obtain a transparent resin of excellent appearance by the addition of methyl methacrylate, but improved the chemical resistance and hygroscopic resistance.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to significantly improve the chemical resistance and hygroscopic resistance without impairing the properties such as heat resistance, transparency and processability, such as optical or display materials It is to provide a method for producing a heat-resistant transparent styrene resin suitable for use in.

delete

The first aspect of the present invention for achieving the above object, provides a styrene resin comprising a styrene repeating unit, (meth) acrylic acid repeating unit and cycloalkyl (meth) acrylate repeating unit.

A second aspect of the present invention for achieving the above object, characterized in that the continuous bulk polymerization of a mixed solution containing a styrene monomer, a (meth) acrylic acid monomer and a cycloalkyl (meth) acrylate monomer and a solvent Provided are a method for producing a styrene resin.

Styrene-based resin according to the production method of the present invention is significantly improved in chemical resistance and hygroscopicity without impairing the properties of the styrene-based resin such as heat resistance, transparency and processability is suitable for use in optical or display materials.

Hereinafter, the present invention will be described in more detail.

The first aspect of the present invention relates to a styrene resin comprising a styrene repeating unit, a (meth) acrylic acid repeating unit and a cycloalkyl (meth) acrylate repeating unit.

Here, the content ratio of the repeating unit is a styrene repeating unit: (meth) acrylic acid repeating unit: cycloalkyl (meth) acrylate repeating unit = 70 ~ 90: 5 ~ 15: 5 ~ 15 is preferably 70 ~ 80: 5-10: 5-10 are more preferable. When the content ratio of the repeating unit is in the above range, it may be excellent in chemical resistance and hygroscopic resistance, but also excellent in appearance.

The polymerization form of the styrene resin may include a random copolymer or an alternating copolymer.

It is preferable that the weight average molecular weights of the said styrene resin are 100,000-300,000.

A second aspect of the present invention is a method for producing a styrene resin, characterized in that the bulk mixture of the styrene monomer, the (meth) acrylic acid monomer, the cycloalkyl (meth) acrylate monomer and a mixed solution containing a solvent. It is about.

In the manufacturing method of the styrene resin of this invention, the said continuous block polymerization,

(a) 5 to 15 parts by weight of solvent, based on 100 parts by weight of the mixed solution, 60 to 80 parts by weight of styrene monomer, 5 to 10 parts by weight of (meth) acrylic acid monomer, and 5 to 5 cycloalkyl (meth) acrylate monomers. Preparing a mixed solution including 10 parts by weight; And

(b) It is preferred to include a step of preparing a polymerization solution by adding 0.01 to 0.1 parts by weight of the polymerization initiator and 0.001 to 0.5 parts by weight of the molecular weight regulator based on 100 parts by weight of the mixed solution prepared.

In addition, the continuous block polymerization (c) is carried out polymerization at a reaction temperature of 100 to 200 ℃ while continuously introducing the prepared polymerization solution into one or more reactors at a rate of 5 to 15 L / hr, preferably It is preferable to carry out at the reaction temperature of 130-160 degreeC, in order to obtain the styrene resin of the quality suitable for the objective of this invention.

The method of the step (c) may further comprise the step of recovering the unreacted monomer and the reaction solvent by adding a solution polymerized in 200 to 260 ℃ volatile bath.

In the present invention, the styrenic repeating unit is selected from the group consisting of repeating units derived from styrene, α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene and o-bromostyrene. It is preferable that it is 1 or more types.

In addition, the styrene-based monomers, styrene, α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene or o-bromostyrene may be used alone or in combination of two or more, double Styrene is most preferred.

The amount of the styrene repeating unit or the amount of the styrene monomer is preferably 60 to 80 parts by weight.

In the present invention, the (meth) acrylic acid repeating unit is a collective term for acrylic acid repeating unit and methacrylic acid repeating unit and may be selected from the group consisting of repeating units derived from acrylic acid, methacrylic acid or derivatives thereof. have.

In addition, the said (meth) acrylic acid type monomer is what it means collectively acrylic acid and methacrylic acid, acrylic acid, methacrylic acid, or derivatives thereof can be used individually or in mixture of 2 or more types, and methacrylic acid is the most preferable among these. .

In the present invention, the cycloalkyl (meth) acrylate repeating unit is a collective term for a cycloalkyl acrylate repeating unit and a cycloalkyl methacrylate repeating unit, preferably having 5 to 20 carbon atoms, and 5 carbon atoms. It is more preferable that it is 12 to.

In addition, the said cycloalkyl (meth) acrylate type monomer means cycloalkyl acrylate and cycloalkyl methacrylate collectively, It is preferable that it is C5-C20, It is more preferable that it is C5-C12, Among these, Cyclohexyl methacrylate is most preferred.

In the present invention, the solvent may be used alone or in combination of two or more kinds of toluene, ethylbenzene, or xylene, of which toluene is most preferred. It is preferable that the usage-amount of the said solvent is 5-15 weight part. When the usage-amount of a solvent is the said range, it is easy to adjust the viscosity of a polymerization solution, and productivity is high.

In the present invention, the polymerization initiator serves to initiate the polymerization reaction, specifically t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3 , 5-trimethyl cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -2-methyl cyclohexane or 2,2-bis (4,4 -Di-t-butylperoxy cyclohexyl) propane can be used alone or in combination of two or more thereof. The amount of the polymerization initiator used is preferably 0.01 to 0.1 parts by weight, more preferably 0.01 to 0.05 parts by weight based on 100 parts by weight of the mixed solution. When the amount of the polymerization initiator used is within the above range, the viscosity does not increase significantly, so that the process is stable and the polymerization proceeds easily and the physical properties of the resin do not decrease.

In the present invention, the molecular weight regulator serves to control the viscosity of the resin, specifically, may be used a thiol-based compound such as t-dodecyl mercaptan and n-octyl mercaptan. The amount of the molecular weight modifier used is preferably 0.001 to 0.5 parts by weight, and more preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the mixed solution. When the usage-amount of a molecular weight modifier is the said range, a viscosity does not rise significantly and a process is stable, but the physical property of resin does not fall.

Another aspect of the present invention relates to a styrene resin produced by the above production method.

The styrene resin according to the present invention preferably has a Haze range of 0.01% to 0.5% when evaluating transparency according to ASTM 1003 method, and a moisture absorption rate of 0.01% to 0.30% when evaluating moisture absorption rate according to ASTM D570.

In addition, the styrene resin according to the present invention has a glass transition temperature of 110 ~ 140 ℃ range, Melt Index (Melt Index) is 10 ~ 30 g / 10 minutes range, the weight average molecular weight is preferably 100,000 to 300,000. .

Hereinafter, preferred examples will be described to aid in understanding the present invention. The following examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

The physical property evaluation method in this invention is as follows.

Glass transition temperature (Tg): measured using a Pyris 6 DSC (Differential Scanning Calroimeter) from Perkin Elmer.

Transparency (Haze): Measured according to ASTM 1003 method.

Appearance characteristics: Injection specimens were measured based on visual discrimination. (○: Good, △: Normal, ×: Poor)

-Hygroscopicity: measured after standing for 48 hours at room temperature according to ASTM D570 method.

-Chemical resistance: Raise the specimen on Jig, dropping a certain amount of methyl alcohol, and then collect the specimen after 24 hours and perform Tensile Test. (○: Good-early tensile strength retention of 80% or more based on initial tensile strength, △: Normal-early tensile strength retention of less than 80% based on initial tensile strength, ×: broken on Jig)

-Fluidity: According to ASTM D1238 method, the number of g of the resin discharged after measuring for 10 minutes at 10 degreeC loads 220 degreeC was measured.

<Examples>

Example  One

1,1-bis (t-butylperoxy) -3 as an organic peroxide initiator in 100 parts by weight of a mixture of 78 parts by weight of styrene, 6 parts by weight of methacrylic acid, 6 parts by weight of cyclohexyl methacrylate, and 10 parts by weight of toluene. A polymerization solution was prepared by adding 0.03 parts by weight of 3,5-trimethyl cyclohexane and 0.02 parts by weight of n-dodecyl mercaptan as a molecular weight regulator.

The prepared polymerization solution was polymerized at a temperature of 140 ° C. while being charged into a 26 L reactor at a rate of 12 L / hr, and then unreacted monomers and reaction solvents were removed at a temperature of 230 ° C. in a volatilization tank to form a heat-resistant transparent copolymer in the form of pellets. Resin was prepared. The physical properties of the resin thus prepared were measured, and the results are shown in Table 1.

Example  2

In preparing the polymerization solution, the same procedure as in Example 1 was carried out except that 74 parts by weight of styrene, 6 parts by weight of methacrylic acid, 10 parts by weight of cyclohexyl methacrylate, and 10 parts by weight of toluene were used, and the results are shown in Table 1. .

Example  3

In preparing the polymerization solution, the same procedure as in Example 1 was carried out except that 76 parts by weight of styrene, 6 parts by weight of methacrylic acid, 8 parts by weight of cyclohexyl methacrylate, and 10 parts by weight of toluene were used, and the results are shown in Table 1. .

Comparative example  One

When preparing the polymerization solution, it was carried out in the same manner as in Example 1 except that 84 parts by weight of styrene, 6 parts by weight of methacrylic acid and 10 parts by weight of toluene were used, and the results are shown in Table 1.

Comparative example  2

When preparing the polymerization solution, it was carried out in the same manner as in Example 1 except that 64 parts by weight of styrene, 6 parts by weight of methacrylic acid, 20 parts by weight of cyclohexyl methacrylate, and 10 parts by weight of toluene were used, and the results are shown in Table 1. .

Comparative example  3

When preparing the polymerization solution, it was carried out in the same manner as in Example 2 except that 10 parts by weight of methyl methacrylate was used, and the results are shown in Table 1.

[Table 1]

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tg (℃) 122 123 122 124 119 122 Haze (%) 0.3 0.3 0.3 3.1 0.6 0.3 Appearance characteristics ○ ○ ○ × △ ○ Chemical resistance ○ ○ ○ ○ △ × Hygroscopicity (%) 0.14 0.21 0.18 0.11 0.30 0.37 liquidity
(g / 10 min) 25 23 24 32 35 20

As shown in Table 1, Examples 1 to 3 prepared by adding 6 to 10 parts by weight of cyclohexyl methacrylate showed excellent appearance characteristics compared to Comparative Example 1 without using cyclohexyl methacrylate. . However, in the case of Comparative Example 2 using an excessive amount of cyclohexyl methacrylate, there was a problem in appearance characteristics and chemical resistance under the influence of residual cyclohexyl methacrylate. In addition, Comparative Example 3 prepared by adding methyl methacrylate was excellent in appearance characteristics, but significantly lowered in chemical resistance and moisture absorption rate.

Claims (19)

delete delete delete delete delete delete Continuous mass polymerization of a mixture containing a styrene monomer, a (meth) acrylic acid monomer and a cycloalkyl (meth) acrylate monomer and a solvent, The continuous block polymerization, (a) a mixed solution containing 60 to 80 parts by weight of a styrene monomer, 5 to 10 parts by weight of a (meth) acrylic acid monomer, and 5 to 10 parts by weight of a cycloalkyl (meth) acrylate monomer, in 5 to 15 parts by weight of a solvent. Manufacturing step; (b) t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3,5-trimethyl cyclohexane, 1,1-bis (t) t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) -2-methyl cyclohexane, and 2,2-bis (4,4-di-t-butylperoxy cyclohexyl) propane 0.01 to 0.1 parts by weight of one or more polymerization initiators selected from the group consisting of t-dodecyl mercaptan, and 0.001 to 0.5 parts by weight of one or more molecular weight regulators selected from the group consisting of n-octyl mercaptan. Preparing a; And (c) polymerizing at a reaction temperature of 100 to 200 ° C. while continuously introducing the prepared polymerization solution into at least one reactor at a rate of 5 to 15 L / hr; Method for producing a styrene-based resin comprising a. delete delete The method for producing a styrene resin according to claim 7, wherein the reaction temperature is 130 to 160 ° C. The method of claim 7, wherein the styrene monomer is one or more selected from the group consisting of styrene, α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene, and o-bromostyrene The manufacturing method of styrene resin characterized by the above-mentioned. The method for producing a styrene resin according to claim 7, wherein the (meth) acrylic acid monomer is at least one member selected from the group consisting of acrylic acid, methacrylic acid and derivatives thereof. The method for producing a styrene resin according to claim 7, wherein the cycloalkyl (meth) acrylate monomer has 6 to 20 carbon atoms. The method for producing a styrene resin according to claim 7, wherein the cycloalkyl (meth) acrylate monomer is cyclohexyl methacrylate. The method of claim 7, wherein the solvent is at least one selected from the group consisting of toluene, ethylbenzene, and xylene. delete delete delete delete