KR20050026176A - Transparency thermoplastic resin and method for preparing a dry powder thereof - Google Patents

Abstract

Provided is a transparent thermoplastic resin which decreases difference of refractive index between conjugated diene rubber latex and compounds mixed with the conjugated diene rubber latex, therefore it minimizes residual of unreacted monomers through spray drying to improve transparency. The transparent thermoplastic resin comprises the components of: 5-60wt% of conjugated diene rubber latex which is possibly styrenes resin showing 800-4000Å in diameter, 60-95% in content for gel and 12-40 in a swelling index; 30-70wt% of methacrylic alkyl ester compounds or acrylic alkyl ester compounds; 8-50wt% of aromatic vinyl compounds; 1-20wt% of vinyl cyan compounds; and 0.05-2wt% of a reactive emulsifier.

Description

Transparency Thermoplastic Resin and Method for Preparing a Dry Powder

The present invention relates to a transparent thermoplastic resin and a method for producing the dried powder thereof. More specifically, a transparent thermoplastic resin suitable for spray drying is prepared by using a reactive emulsifier in graft copolymerization of a mixture of conjugated diene rubber latex, a methacrylic acid alkyl ester compound, an aromatic vinyl compound, and a vinyl cyan compound, and spraying To prepare a dry powder through drying to reduce the residual amount of the unreacted monomer, to reduce the difference in the refractive index of the conjugated diene rubber latex and the mixture graft copolymerized therein to provide a transparent thermoplastic resin with increased transparency and a dry powder thereof It is about.

Transparent ABS resin is made of polybutadiene rubber latex or polystyrene-butadiene rubber latex by graft copolymerization of methacrylic acid alkyl ester compound, aromatic vinyl compound, vinyl cyan compound, etc. It is a thermoplastic resin with excellent processability and excellent mechanical rigidity and transparency.

Most of these transparent ABS resins are produced by emulsion polymerization. The final product is obtained by manufacturing the transparent ABS latex through emulsion polymerization and by pressing and ejecting the dried powder obtained through the dry powder through the coagulation, drying and dehydration processes. The flocculation and dehydration process to obtain the dry powder in the series of processes requires a considerable investment of equipment, there is a problem that there is a large amount of waste water generated, which may cause environmental pollution problems, and the yield is lowered.

Another method for obtaining a dry powder is to spray-dry the latex in a hot wind. This spray drying method has significant advantages in plant and waste water problems and yield problems and can minimize the monomers remaining in the dry powder. If unreacted monomers remain, surface gloss is poor at the time of injection, lowering the transparency of the final product, and adversely affects the human body due to the toxicity of the monomers.

Spray drying can minimize these residual monomers. However, in spite of these various advantages, since there is no dehydration process, most of the emulsifiers used in the reaction remain, and the remaining emulsifiers have a problem of significantly deteriorating the thermal stability of the final product.

In Korean Patent Application No. 2001-0065640, a powder was prepared by emulsion polymerization of an impact modifier and spray drying. Since the impact modifier uses less than 10% of the final product, the thermal stability of the dry powder does not appear to decrease the thermal stability of the final product.However, in the case of ABS resin or transparent ABS resin, the dry powder is not less than 40 and up to 100%. Because of its use, the thermal stability of the final product has a significant adverse effect.

In Japanese Patent Laid-Open No. 2000-072882, this problem has been significantly improved by using various heat stabilizers, but there is a problem in economics at the cost of the stabilizer. In Japanese Patent Laid-Open No. 2002-226595, overheating in place of hot air in the spray drying process is disclosed. The use of water vapor eliminates the problem of automatic oxidation and ignition during drying, but there is a problem that does not solve the thermal stability of the underlying dry powder.

In order to solve the above problems, an object of the present invention is to provide a transparent thermoplastic resin suitable for spray drying excellent in thermal stability and improved transparency and a method for producing the dried powder thereof.

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

The present invention to achieve the above object,

5 to 60 parts by weight of a conjugated diene rubber latex, 30 to 70 parts by weight of an alkyl methacrylate compound or an acrylic acid lacyl ester compound, 8 to 50 parts by weight of an aromatic vinyl compound, 1 to 20 parts by weight of a vinyl cyan compound, and a reactive emulsifier 0.05 It provides a transparent thermoplastic resin, characterized in that consisting of to 2 parts by weight.

The conjugated diene rubber latex may be a styrene resin having a particle diameter of 800 to 4,000 kPa, a gel content of 60 to 95%, and a swelling index of 12 to 40.

The said methacrylic acid alkyl ester compound or acrylic acid lakyl ester compound is (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid decyl ester , (Meth) acrylic acid lauryl ester, and mixtures thereof.

The aromatic vinyl compound may be selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and mixtures thereof.

The vinyl cyan compound may be selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and mixtures thereof.

The reactive emulsifier is an anionic reactive emulsifier comprising an aryl group, a nonionic reactive emulsifier comprising an allyl group, an anionic reactive emulsifier comprising a (meth) acryloyl group, an anionic reactive including a propenyl group Emulsifiers, and mixtures thereof.

The refractive index difference between the refractive index of the conjugated diene rubber latex and the mixture of the methyl acrylate alkyl ester compound, the acrylic acid alkyl ester compound, the aromatic vinyl compound, and the vinyl cyan compound may be 0.005 or less.

Solid content of the graft copolymer latex may be 40% or more.

Preparation of a transparent thermoplastic resin graft copolymerized with a methacrylic acid alkyl ester compound or an acrylic acid lackill ester, an aromatic vinyl compound, and a vinyl cyan compound using a reactive emulsifier and a manufacturing step of the transparent thermoplastic resin in a conjugated diene rubber latex It provides a dry powder manufacturing method of a transparent thermoplastic resin, characterized in that comprises a dry powder manufacturing step of spray drying the transparent thermoplastic resin.

The conjugated diene rubber latex may be a styrene-based particle size of 800 to 4,000 Pa gel content of 60 to 95%, swelling index of 12 to 40.

The said methacrylic acid alkyl ester compound or acrylic acid lakyl ester compound is (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid decyl ester , (Meth) acrylic acid lauryl ester, and mixtures thereof.

The aromatic vinyl compound may be selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and mixtures thereof.

The vinyl cyan compound may be selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and mixtures thereof.

The reactive emulsifier is an anionic reactive emulsifier comprising an aryl group, a nonionic reactive emulsifier comprising an allyl group, an anionic reactive emulsifier comprising a (meth) acryloyl group, an anionic reactive including a propenyl group Emulsifiers, and mixtures thereof.

The refractive index difference between the refractive index of the conjugated diene rubber latex and the mixture of the methyl acrylate alkyl ester compound, the acrylic acid alkyl ester compound, the aromatic vinyl compound, and the vinyl cyan compound may be 0.005 or less.

Solid content of the graft copolymer latex may be 40% or more.

It provides a dry powder of a transparent thermoplastic resin produced by the above production method.

Hereinafter, the present invention will be described in detail.

5 to 60 parts by weight of conjugated diene rubber latex (based on solids), 20 to 70 parts by weight of an alkyl methacrylate compound or an acrylic acid alkyl ester compound, 8 to 50 parts by weight of an aromatic vinyl compound, and 1 to 20 parts by weight of a vinyl cyan compound Copolymerize. The conjugated diene rubber latex used is a common butadiene rubber latex or styrene-butadiene copolymer rubber latex, and graft copolymerization is prepared by emulsion polymerization method.

The refractive index of the monomer mixture used at this time absolutely affects the transparency, and this refractive index is controlled by the amount of the monomer used and the mixing ratio. That is, in order to have transparency, the refractive index of the conjugated diene compound used as a seed for grafting should be similar to the refractive index of the entire grafted component, and the refractive index of the conjugated diene compound and the entire grafted component coincide. good. If the difference in refractive index between the conjugated diene rubber latex refractive index and the entire compound grafted thereto is not more than 0.005, it is not suitable for the present invention.

Generally, the refractive index of the monomer used is butadiene 1.518, methyl methacrylate is about 1.49, styrene is 1.592, acrylonitrile is about 1.52, the refractive index of the grafted polymer can be calculated as follows.

Refractive Index of Transparent Thermoplastic Resin = Wt _A × RI _A + Wt _S × RI _S + Wt _M × RI _M

Wt _A = weight percent of vinyl cyan compound, RI _A = refractive index of vinyl cyan polymer (1.52)

Wt _S = weight percent of the aromatic vinyl compound,

RI _S = refractive index of aromatic vinyl polymer (1.592)

Wt _M =% by weight of alkyl acrylate or alkyl methacrylate compound

RI _M = refractive index of alkyl acrylate or alkyl methacrylate compound (1.49)

Examples of the aromatic vinyl compound used in the present invention include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and the like. In particular, styrene is preferable, and the vinyl cyan compound is preferably acrylonitrile or methacrylonitrile. As a (meth) acrylic-acid alkylester compound, (meth) acrylic-acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid decyl ester, (meth) Acrylic acid lauryl ester and the like, and methyl methacrylate, which is (meth) acrylic acid methyl ester, is most preferred.

As an emulsifier to be used in the present invention, a reactive emulsifier is prepared by mixing one or two or more kinds. When non-reactive emulsifiers such as sulfonated alkyl esters, fatty acid soaps, and alkali salts of rosin acids are generally used, the thermal stability of the dry powder is reduced after spray drying.

 Unlike the non-reactive emulsifier, the reactive emulsifier is directly connected to the main chain of the polymer, thereby minimizing thermal stability by the emulsifier and reducing the amount of antifoaming agent added, thereby reducing the degree of transparency decrease. In addition, since it is bonded to the polymer backbone, it is possible to improve impact resistance, heat colorability, and moist heat resistance.

The reactive emulsifier used in the present invention includes an anionic reactive emulsifier including an allyl group, a (meth) acryloyl group, and a propenyl group and a nonionic reactive emulsifier which is an ethylene oxide adduct. For example, commercially available is the ADEKA REASOAP SETM series (product of Asahi Denka) which is a sulfonic acid ester of polyoxyethylene allylglycidyl nonylphenyl ether, an anionic reactive emulsifier containing an allyl group.

Commercially available nonionic reactive emulsifiers containing allyl groups include the ADEKA REASOAP NETM series (manufactured by Asahi Denka), which is a polyoxyethylene allylglycidyl nonylphenyl ether. An example of an anionic reactive emulsifier containing a (meth) acryloyl group is ELEMINOL RSTM series (manufactured by Sanyo Kasei).

HITENOL HSTM series (product of Daiichi Kogyo Seiyaku Co., Ltd.), which is an ammonium salt of sulfonic acid ester of polyoxyethylene nonyl propenyl ether, an anionic reactive emulsifier containing propenyl group, is commercialized. Reactive emulsifiers used in the present invention are not limited to the above-mentioned products and include all reactive emulsifiers including double bonds capable of participating in the reaction during polymerization.

In addition, the amount of the reactive emulsifier to be used is preferably 0.05 to 2 parts by weight based on 100 parts by weight of the copolymerized monomer mixture. If the content of the reactive emulsifier is less than 0.05 parts by weight, there is a problem that a sufficient latex stability can not be obtained. If the content of the reactive emulsifier exceeds 2 parts by weight, the latex stability is excellent, but it is present on the latex without binding to the polymer main chain and then spray dried. The thermal stability of the dry powder obtained falls.

The solids content of the graft copolymers in the present invention should be at least 40% and more preferably at least 45%. The method of obtaining dry powder using spray drying is related to the amount of evaporated water, and the amount of evaporated water is directly related to the amount of energy used, for example, the amount of power. If the solids content is low, the amount of water to be evaporated increases, leading to an increase in power. In addition, the rate of loading of the latex is reduced due to the increase in the amount of water to be evaporated. This leads to a decrease in productivity. Solid content below 40% is undesirable due to increased power and reduced productivity.

After the completion of the polymerization, the polymerization conversion rate of the latex was 98% or more, and an antioxidant and a stabilizer were administered to the latex to obtain a dry powder using a spray drying apparatus, and the dry powder was prepared as a final product through extrusion. When manufacturing a dry powder by spray drying with the latex described in this patent, a dry powder having excellent thermal stability can be obtained with a higher yield and improved productivity in a shorter time than a dry powder through agglomeration, dehydration and a drying process. In addition, it is possible to solve the environmental problems caused by the waste water, the content of the unreacted monomer remaining in the powder can be lowered below 500ppm, preferably below 100ppm.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

Example 1

In a nitrogen-substituted polymerization reactor, 15 parts by weight of ion-exchanged water and HITENOL HS-10TM (manufactured by Daiichi Kogyo Seiyaku) were emulsified in 15 parts by weight of a rubber latex having a gel content of 70% having an average particle diameter of 0.3 μm. Furnace 0.3 parts by weight, methyl methacrylate 54 parts by weight, styrene 21 parts by weight, acrylonitrile 5 parts by weight, tertiary dodecyl mercaptan 0.5 parts by weight, sodium pyrophosphate 0.096 parts by weight, dextrose 0.024 parts by weight, sulfur 0.002 parts by weight of ferrous topicate and 0.08 parts by weight of cumene hydroperoxide were continuously administered at 75 ° C. for 5 hours to react. After the reaction, the temperature was raised to 80 ° C., and aged for 1 hour to terminate the reaction. At this time, the polymerization conversion rate was 99% and the solidified content was 0.3%. The solids content of the latex prepared was 50%.

The latex was sprayed with an antioxidant and stabilizer to spray dry at a spray drying apparatus (Mobile Minor 2000 Model E of Niro, Japan) at 220 ° C., 1 bar, and a latex feed rate of 70 g / min to obtain dry particles. The analysis was carried out according to the following test method. After the antioxidant and stabilizer were added to the obtained dry particles, pellets were prepared using a twin screw kneader at 200 ° C. to 230 ° C., and the pellets were injected again to measure physical properties according to the following test methods. Indicated.

Comparative Example 1

An antioxidant and a stabilizer were administered to the latex obtained after the polymerization in the same manner as in the above-described embodiment, and then agglomerated with an aqueous calcium chloride solution at a temperature of 80 ° C. or higher, followed by dehydration and drying to obtain a powder. The obtained powder was subjected to extrusion injection in the same manner as in Example 1, and physical properties were measured.

Comparative Example 2

In Example 1, 200 parts by weight instead of 100 parts by weight of ion-exchanged water was used to change the solids content of the latex to 33.3%.

Comparative Example 3

Polymerization was carried out using potassium salt of oleic acid instead of HITENOL HS-10TM (manufactured by Daiichi Kogyo Seiyaku, Ltd.) used as an emulsifier in Example 1 above.

[Comparative Examples 4 and 5]

In Example 1 described above, the amount of the emulsifier HITENOL HS-10TM (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was polymerized using 0.03 parts by weight and 3 parts by weight, respectively, instead of 0.3 parts by weight.

Test Items

* Residual monomer: Dissolve the dry powder in methanol to extract residual monomer. The methanol solution from which the residual monomers were extracted was measured using GC.

* Moisture content: After drying the dried particles for one day completely at 80 ℃ as a way to determine how much moisture in the dried particles, the change in moisture before and after complete drying.

Moisture content = (mass before complete drying-mass after complete drying) / (mass after complete drying)

If the moisture content is high, it is difficult to feed during extrusion, which may cause discoloration.

Haze Value: ASTM D1003

* Retention thermal stability

After leaving the obtained dry polymer for 10 minutes in the injection molding machine of the molding temperature of 250 degreeC, the grade discolored by the following formula with respect to the molded test piece is shown in Table 1.

Here, ΔE is an arithmetic mean value of Hunter Lab values before and after retention, and the closer to 0, the better retention thermal stability.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Residual Monomer (ppm) 80 1050 180 70 80 Moisture content (%) 0.7 1.1 7.5 0.8 0.8 Haze 1.5 1.8 1.6 2.1 1.8 ΔE 3.3 3.0 3.7 6.7 7.1

When manufacturing a dry powder through a flocculation process as in Comparative Example 1, there is a high possibility of problems such as mold corrosion when used for a long time due to the large amount of residual monomer. As shown in Comparative Example 2, when the solid content of the polymerized latex was low, the water content of the dry powder was increased, resulting in discoloration during extrusion.

On the other hand, when spraying latex with low solid content, the temperature is increased in order to lower the moisture content, or when the drying rate is lowered, there is a disadvantage in that productivity is lowered. Comparing Example 1 with Comparative Examples 3 and 5, the retention thermal stability was good when the reactive emulsifier was used in an appropriate amount. In the case of Comparative Example 4, the polymerization failed due to the decrease in stability by using a small amount of an emulsifier.

As described above, the present invention has the effect of providing a transparent thermoplastic resin suitable for spray drying and excellent thermal stability by using a reactive emulsifier during graft copolymerization, and has a refractive index of a conjugated diene rubber latex and a mixture polymerized thereto. By reducing the difference and spray drying to minimize the residual amount of the unreacted monomer has the effect of increasing the transparency.

While the invention has been described in detail above with reference to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope and spirit of the invention, and such variations and modifications are within the scope of the appended claims. It is natural to belong.

Claims (17)

5 to 60 parts by weight of a conjugated diene rubber latex, 30 to 70 parts by weight of an alkyl methacrylate compound or an acrylic acid lacyl ester compound, 8 to 50 parts by weight of an aromatic vinyl compound, 1 to 20 parts by weight of a vinyl cyan compound, and a reactive emulsifier 0.05 Transparent thermoplastic resin, characterized in that comprises from 2 parts by weight. The method of claim 1, The conjugated diene rubber latex is a transparent thermoplastic resin, characterized in that the styrene resin having a particle size of 800 to 4,000 Å, gel content of 60 to 95%, swelling index of 12 to 40. The method of claim 1, The said methacrylic acid alkyl ester compound or acrylic acid lakyl ester compound is (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid decyl ester , (Meth) acrylic acid lauryl ester, and a mixture thereof. The method of claim 1, And said aromatic vinyl compound is selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and mixtures thereof. The method of claim 1, The vinyl cyan compound is selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and mixtures thereof. The method of claim 1, The reactive emulsifier is an anionic reactive emulsifier comprising an aryl group, a nonionic reactive emulsifier comprising an allyl group, an anionic reactive emulsifier comprising a (meth) acryloyl group, an anionic reactive including a propenyl group A transparent thermoplastic resin, characterized in that it is selected from the group consisting of emulsifiers, and mixtures thereof. The method of claim 1, And a refractive index difference between the refractive index of the conjugated diene rubber latex and the mixture of the methylacrylic acid alkyl ester compound, the acrylic acid alkyl ester compound, the aromatic vinyl compound, and the vinyl cyan compound is 0.005 or less. The method of claim 1, Transparent thermoplastic resin, characterized in that the solid content of the graft copolymer latex is 40% or more. Preparing a graft copolymer latex which graft copolymerizes a methacrylic acid alkyl ester compound or an acrylic acid laalkyl ester, an aromatic vinyl compound, and a vinyl cyan compound to a conjugated diene rubber latex using a reactive emulsifier; And A dry powder manufacturing step of spray-drying the graft copolymer latex prepared in the manufacturing step of the graft copolymer latex; Dry powder manufacturing method of a transparent thermoplastic resin, characterized in that comprises a. The method of claim 9, The conjugated diene rubber latex has a particle diameter of 800 to 4,000 Å gel content of 60 to 95%, swelling index of 12 to 40, characterized in that the dry powder manufacturing method of a transparent thermoplastic resin. The method of claim 9, The said methacrylic acid alkyl ester compound or acrylic acid lakyl ester compound is (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid decyl ester , (Meth) acrylic acid lauryl ester, and a mixture thereof. The method of claim 9, And said aromatic vinyl compound is selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, and mixtures thereof. The method of claim 9, The vinyl cyan compound is selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and mixtures thereof. The method of claim 9, The reactive emulsifier is an anionic reactive emulsifier comprising an aryl group, a nonionic reactive emulsifier comprising an allyl group, an anionic reactive emulsifier comprising a (meth) acryloyl group, an anionic reactive including a propenyl group Method for producing a dry powder of a transparent thermoplastic resin, characterized in that selected from the group consisting of emulsifiers, and mixtures thereof. The method of claim 9, The dry powder of the transparent thermoplastic resin characterized in that the refractive index difference of the mixture which the refractive index of the said conjugated diene rubber latex and the said methyl acrylate alkylester compound, the acrylic acid alkylester compound, the aromatic vinyl compound, and the vinyl cyan compound mixed is 0.005 or less. Manufacturing method. The method of claim 9, Method for producing a dry powder of a transparent thermoplastic resin, characterized in that the solid content of the graft copolymer latex is 40% or more. The dry powder of the transparent thermoplastic resin manufactured by any one of Claims 9-16.