KR100415151B1 - Transparent high impact polystyrenic resins composition with good mold release and their prodution method - Google Patents

Abstract

The present invention relates to an impact resistant styrene-based transparent resin composition excellent in mold release property and a method for producing the same. The present invention provides for this purpose: a) in the presence of 4 to 10 parts by weight of a styrene-butadiene copolymer which is a block or random copolymer having a styrene skeleton content of 15 to 50%; b) 30 to 60 parts by weight of styrene monomer; c) 40 to 70 parts by weight of (meth) acrylic acid alkyl ester monomer; Claims [1] A thermoplastic transparent resin composition prepared by graft copolymerization of a monomer mixed solution mixed in a weight ratio of graft copolymer in a continuous process including a polymerization initiator, comprising: d) 0.02 to 0.4 parts by weight of a low molecular weight hydrocarbon polymer; Or e) 0.02 to 0.4 parts by weight of a metal salt mixture of a hydrocarbon polymer and a higher fatty acid, and an excellent impact resistance styrene transparent resin composition and a method of manufacturing the same.

The impact-resistant styrene-based transparent resin composition of the present invention is excellent in transparency, impact resistance, processability and hygroscopicity, and in particular, it is excellent in releasability when manufacturing injection molded articles, and thus, it is possible to manufacture injection molded articles having various structures.

Description

Transparent high impact polystyrenic resins composition with good mold release and their prodution method

The present invention relates to a method for producing a rubber-modified styrenic copolymer transparent resin having excellent transparency, impact resistance, processability and mold release property, and in particular, the presence of styrene-butadiene copolymer rubber, which is a block or random copolymer having a styrene skeleton content of 15 to 50%. Graft copolymerization of styrene-based monomers and (meth) acrylic acid alkyl ester-based monomers to produce rubber-modified styrene-based copolymer transparent resins having excellent transparency, impact resistance, processability and hygroscopicity. It is about a method.

Rubber modified styrene resin is a thermoplastic resin obtained by graft copolymerization of styrene monomers in the presence of a rubber polymer, which is one of the disadvantages of styrene resins. Although it has been used in various fields requiring impact resistance as a sheet, the rubber particles dispersed in the resin has lost transparency, which is one of the advantages of the styrene-based resin, and has been limited in its use in transparent applications. Accordingly, a technology for producing rubber-modified styrene resins having excellent transparency for various applications has been studied. Impact-resistant transparent resin produced by this method has recently been increased in the production of complex structural moldings as it is applied to various designs. In recent years, the transparent resin manufacturing methods up to now do not balance the requirements for transparency, impact resistance, mold release and processability, making it difficult to manufacture complex injection molding products, and cracks during mold release after injection molding due to the lack of mold release. Occurs or the shape is deformed. In order to solve these problems, silicone oil and metal salts may be added as a release agent, but when silicone oil and metal salts are added to the transparent resin, the release property is improved, but the transparency is affected and the transparency is reduced. . The present invention is to provide a method for imparting good release properties without affecting the transparency in the production of transparent moldings of various structures.

An object of the present invention is to provide an impact resistant styrene-based transparent resin composition and a method for producing a resin having excellent release properties while maintaining properties such as transparency, impact resistance, and workability in consideration of the problems of the prior art. Another object of the present invention is to provide an impact resistant styrene-based transparent resin composition excellent in transparency, impact resistance, processability, and releasability, and having good gloss, and a method for continuously producing the resin.

The present invention to achieve the above object,

a) 4 to 10 parts by weight of a styrene-butadiene copolymer which is a block or random copolymer having a styrene skeleton content of 15 to 50%;

b) 30 to 60 parts by weight of styrene monomer

c) 40 to 70 parts by weight of (meth) acrylic acid alkyl ester monomer;

In the thermoplastic transparent resin composition prepared by graft copolymerization of the mixed monomer mixture solution in a continuous process including a polymerization initiator,

d) 0.02 to 0.4 parts by weight of low molecular weight hydrocarbon polymer; or

e) It provides a shock-resistant styrene-based transparent resin composition excellent in releasability comprising 0.02 to 0.4 parts by weight of a metal salt mixture of a hydrocarbon polymer and a higher fatty acid.

In addition, the present invention

a) 4 to 10 parts by weight of a styrene-butadiene copolymer which is a block or random copolymer having a styrene skeleton content of 15 to 50%;

b) 30 to 60 parts by weight of styrene monomer

c) 40 to 70 parts by weight of (meth) acrylic acid alkyl ester monomer;

In the thermoplastic transparent resin composition prepared by mixing a monomer mixed solution mixed in a weight ratio of a polymerization initiator,

d) 0.02 to 0.4 parts by weight of low molecular weight hydrocarbon polymer; or

e) 0.02 to 0.4 parts by weight of a metal salt mixture of a hydrocarbon polymer and a higher fatty acid

It provides a method for producing a shock-resistant styrene-based transparent resin composition excellent in releasability comprising the step of graft copolymerization by continuous solution polymerization including the step of preparing an impact-resistant styrene-based transparent resin.

Hereinafter, the present invention will be described in detail.

The present invention is a rubber-modified styrene system prepared by a method comprising graft copolymerization of a styrene monomer and a (meth) acrylic acid alkyl ester monomer in the presence of a styrene-butadiene block or a styrene-butadiene copolymer rubber which is a random copolymer. In the production of impact-resistant transparent resin in a continuous process, by adding a low molecular weight hydrocarbon polymer or a mixture of a hydrocarbon salt and a metal salt of a higher fatty acid to improve the releasability, it can have excellent releasability while maintaining properties such as transparency and impact resistance It would be. In particular, when a low molecular weight hydrocarbon polymer is used, the release effect can be easily increased without affecting the transparency and impact strength. The present invention provides a transparency and impact resistance comprising graft copolymerization of a styrene monomer with a (meth) acrylic acid alkyl ester monomer in the presence of a styrene-butadiene copolymer rubber, a block or random copolymer having a styrene skeleton content of 15 to 50%. It is applied in the preparation of rubber modified styrene-based copolymer transparent resin having excellent workability and hygroscopicity. Hereinafter, the present invention will be described in detail.

a) 4 to 10 parts by weight of a styrene-butadiene copolymer which is a block or random copolymer having a 5% styrene solution viscosity of 20 to 50cp and a styrene skeleton content of 25 to 50% at 25 ° C,

Ii) 30 to 60 parts by weight of styrene monomer; And

Iii) 40 to 70 parts by weight of (meth) acrylic acid alkyl ester monomer

Preparing a raw material mixed solution by dissolving in 100 parts by weight of a monomer mixed solution mixed in a weight ratio of the mixed solution;

b) graft copolymerizing the mixed solution of step a) at a reactor temperature of 120 to 145 ° C. into a first reactor of a continuous polymerization apparatus in which two or more stirring reactors are connected in series;

c) a copolymerization step of obtaining the final polymer by continuously introducing the copolymer of step b) into two or more in series connected reactors;

d) in the polymer production step of step a) or b) or c)

Iii) a low molecular weight hydrocarbon polymer; or

Ii) adding 0.02 to 0.4 parts by weight of a metal salt mixture of a hydrocarbon polymer and a higher fatty acid;

e) devolatilizing and pelletizing the final copolymer of step c);

To prepare a rubber-modified styrene-based copolymer transparent resin by the method comprising a.

In step a), a) i) styrene-butadiene copolymer preferably has a styrene skeleton content of 15 to 50%. If the styrene skeleton content is less than 15% or more than 50%, transparency and impact resistance are not balanced. In addition, it is preferable in terms of transparency and impact resistance that a 5% styrene solution viscosity of 20 to 50cp at 25 ° C.

The rubber polymer of step a) is preferably 4 to 10 parts by weight in a mixed solution of a) ii) styrene-based monomers and a) iii) (meth) acrylic acid alkyl ester monomers or a solvent. If the rubber polymer of step a) is less than 4 parts by weight, the impact resistance of the produced resin is significantly lowered, and if it exceeds 10 parts by weight, transparency is lowered, which is not preferable.

The styrene monomers of a) ii) include alkyl styrenes such as styrene, α -methyl styrene, o -methyl styrene, p -methyl styrene, m -methyl styrene, ethyl styrene, i -butyl styrene and t -butyl styrene; And halogenated styrenes such as o -bromo styrene, p -bromo styrene, m -bromo styrene, o -chloro styrene, p -chloro styrene, m -chloro styrene, and the like. It is styrene.

The a) iii) (meth) acrylic acid alkyl ester monomers are one from the group consisting of methyl methacrylate, ethyl methacrylate, n -butyl methacrylate, 2-methyl hexyl acrylate and 2-ethyl hexyl acrylate. The above may be selected, and preferably, a mixture of methyl methacrylate and n -butyl acrylate is used.

In the present invention, the weight ratio of a) ii) styrene monomer and a) iii) (meth) acrylic acid alkyl ester monomer in the monomer mixed solution is preferably 30 to 60:40 to 70. In addition, it is important from the viewpoint of transparency to determine two types of monomer composition such that the refractive index of the rubber polymer and the refractive index of a) ii) styrene monomer and a) iii) (meth) acrylic acid alkyl ester monomer copolymer are identical.

In addition, the average particle diameter of the rubber particles in the rubber-modified styrene-based copolymer transparent resin prepared by the above manufacturing method was excellent in transparency when the particle size is 1.0 μm or less, and in terms of transparency and impact resistance, the average particle diameter is preferably 0.3 to 0.8 μm. to be.

The low molecular weight hydrocarbon polymer used in step d) improves releasability without affecting the transparency and impact resistance of the transparent resin. The low molecular weight hydrocarbon polymer used in the present invention preferably has a viscosity average molecular weight of about 500 to 3000. If the average molecular weight is less than 500 or more than 3000, transparency and releasability cannot be balanced. In other words, when the average molecular weight is less than 500, it does not show any effect on the improvement of releasability, and when 3000 or more, the releasability is improved, but the transparency of the transparent resin copolymer of the present invention is greatly reduced. As addition amount, 0.02-0.4 weight part is preferable. If the amount exceeds 0.4 parts by weight or more, the release effect is increased, but the transparency is significantly lowered, which is not preferable, and at 0.02 parts by weight or less, it does not help to improve releasability. It is also possible to use mixtures of metal salts of the hydrocarbon polymer of ii) with higher fatty acids to enhance the releasability. When the metal salt mixture of the hydrocarbon polymer and the higher fatty acid is used, the metal salt of the higher fatty acid may be zinc stearate or magnesium stearate. It is also preferable to add 0.02-0.4 weight part at this time. However, considering the transparency and impact resistance, it is very good to use a low molecular weight hydrocarbon alone. The low molecular weight hydrocarbon polymer used in the present invention may be used in two processes, that is, in addition to the final polymer, but it is very desirable and effective to directly add during the polymerization process in consideration of transparency, release property, and addition amount.

In the production method of the present invention, a rubber-modified styrenic copolymer resin can be prepared by adding a polymerization initiator, a mercaptan-based chain transfer agent, a solvent, a plasticizer, an antioxidant, or an ultraviolet absorber used in a conventional polymer polymerization.

Specifically, the mercaptan-based chain transfer agent used in the present invention may be selected from the group consisting of n -octyl mercaptan, n -dodecyl mercaptan, t -dodecyl mercaptan and α-methyl styrene dimer.

Further, as the polymerization initiator, peroxy ketals such as 1,1-bis ( t -butyl peroxy) -3,3,5-trimethyl cyclohexane; Dialkyl peroxides such as di- t -butyl peroxide and 2,5-dimethyl-2,5-di (t-butyl peroxy) hexane; Diacyl peroxides such as dibenzoyl peroxide; peroxy esters such as t -butyl peroxy isopropyl carbonate; Kenon peroxides, such as a cyclohexanone peroxide; And an azo compound such as 2,2′-azobisisobutylonitrile and the like, and an organic peroxide capable of increasing the graft efficiency and reducing the average particle diameter of the rubber particles is preferable.

The polymerization solvent may be used to lower the viscosity of the polymerization solution, and may be used in an amount of 10 to 25 parts by weight based on 100 parts by weight of the raw material monomer, for example, one or more selected from the group consisting of toluene, ethylbenzene, and xylene. have.

As the manufacturing process used in the present invention, continuous or batch bulk polymerization, solution polymerization or block-suspension polymerization is possible, and continuous bulk polymerization or solution polymerization is preferable in that there is no problem of productivity and quality uniformity and water pollution. .

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

[Examples and Comparative Examples]

Example 1

7.0 parts by weight of styrene-butadiene block copolymer rubber (25 ° C., 5% styrene solution viscosity 39cp, styrene skeleton content 40%), styrene 33.0 parts, methyl methacrylate 32.0 parts, n- butyl acrylate 3.0 parts and ethyl After preparing a monomer solution consisting of 25.0 parts by weight of benzene, 0.02 parts by weight of 1,1-bis ( t -butyl peroxy) -3,3,5-trimethyl cyclohexane was added thereto as a polymerization initiator. The mixed solution was introduced into a continuous polymerization apparatus in which four stirred reactors were connected in series and subsequently graft copolymerized. 0.3 parts by weight of a low molecular weight hydrocarbon polymer (viscosity average molecular weight 900) was introduced into the polymer during the polymerization step. The temperature at the inlet of the polymerization apparatus was 125 ° C and the temperature at the outlet was 140 ° C. The final copolymer mixed solution was sent to a devolatilization tank to remove unreacted monomers and solvents at 230 ° C. and 20 torr, and then pelletized to obtain a final rubber-modified styrene copolymer transparent resin. After the injection molding of the resin obtained as described above to measure the physical properties as shown in Table 1 below.

Haze: An injection test piece having a thickness of 3 mm was prepared and measured according to ASTM 1003.

-Total light transmittance: Measured in accordance with ASTM 1003 by making an injection test piece of thickness 3㎜.

-Izod impact strength: 12.7 × 64 × 6.4 mm injection test specimen was produced and measured in accordance with ASTM D256.

- releasing property: the ejection pins when the cup Extrusions are taken out of the molding conditions of 3.0 ounce cup mold (Ø = 58mm, H = 100mm ) by using a injection molding machine with an injection temperature of 210 ℃, 5kg / cm ^2, a mold temperature of 60 ℃ of Evaluated by measuring the pressure applied.

The release property is better the lower the measured value.

Example 2

It was carried out in the same composition as in Example 1, and prepared with an amount of release agent of 0.15 parts by weight.

Example 3

It was carried out in the same composition as in Example 1, and was used as a release agent using a metal salt mixture of a hydrocarbon polymer and a higher fatty acid. A hydrocarbon polymer and zinc-stearate were mixed at 0.15 parts by weight to prepare a total dosage of 0.3 parts by weight.

Comparative Example 1

The same composition as in Example 1 was carried out, and a mold release agent was not added to prepare a styrene-based copolymer transparent resin.

Comparative Example 2

It was carried out in the same composition as in Example 1, and prepared with an amount of release agent of 0.5 parts by weight.

Comparative Example 3

It is the same as Example 1 except that the viscosity average molecular weight of the hydrocarbon polymer which is a release agent used is 450.

Comparative Example 4

It is the same as Example 1 except that the viscosity average molecular weight of the hydrocarbon polymer which is a mold release agent used was 4000.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Haze 4.8 4.8 4.8 4.7 9.3 4.9 11.2 Total light transmittance 89.9 89.9 89.8 89.8 87.9 89.8 88.0 Izod impact strength 5.6 5.5 5.5 5.4 5.6 5.4 5.7 Dysplasia 1,250 1,430 1,390 2,400 1,150 2,150 1,470

The impact resistant styrene-based transparent resin composition of the present invention exhibits balanced physical properties in transparency, impact resistance, processability, and the like, and is particularly advantageous in producing molded injection molding having various structures due to its excellent release property.

Claims (9)

a) 4 to 10 parts by weight of a styrene-butadiene copolymer which is a block or random copolymer having a styrene skeleton content of 15 to 50%; b) 30 to 60 parts by weight of styrene monomer c) 40 to 70 parts by weight of (meth) acrylic acid alkyl ester monomer; In the thermoplastic transparent resin composition prepared by graft copolymerization of the mixed monomer mixture solution in a continuous process including a polymerization initiator, 0.02 to 0.4 parts by weight of a low molecular weight hydrocarbon polymer; or An impact resistant styrene-based transparent resin composition having excellent release property comprising 0.02 to 0.4 parts by weight of a metal salt mixture of a low molecular weight hydrocarbon polymer and a higher fatty acid. The styrene-butadiene copolymer according to claim 1, wherein the styrene-butadiene copolymer has a 5% styrene solution viscosity of 20 to 50 cps (centipoise) at 25 ° C. The method according to claim 1 or 2, Styrene-based monomers include alkyl styrenes such as styrene, α- methyl styrene, o -methyl styrene, p -methyl styrene, m -methyl styrene, ethyl styrene, i -butyl styrene and t -butyl styrene; And halogenated styrenes such as o -bromo styrene, p -bromo styrene, m -bromo styrene, o -chloro styrene, p -chloro styrene, and m -chloro styrene, The (meth) acrylic acid alkyl ester monomer is at least one member selected from the group consisting of methyl methacrylate, ethyl methacrylate, n -butyl methacrylate, 2-methyl hexyl acrylate and 2-ethyl hexyl acrylate. Impact resistant styrene-based transparent resin composition excellent in the releasability. 3. The impact resistant styrene of claim 1, wherein the low molecular weight hydrocarbon polymer has a viscosity average molecular weight of 500 to 3000 and the metal salt of the higher fatty acid is zinc-stearate or magnesium-stearate. System transparent resin composition. a) preparing a raw material mixed solution by dissolving a styrene-butadiene copolymer rubber, a block or random copolymer having a styrene skeleton content of 15 to 50%, in a mixed solution of a styrene monomer and an (meth) acrylic acid alkyl ester monomer; b) graft copolymerizing the mixed solution of step a) into a first reactor of a continuous polymerization apparatus in which two or more stirred reactors are connected in series; c) graft copolymerizing the copolymer of step b) into a second or more reactor; d) devolatilizing and pelletizing the copolymer of step c); And e) during the polymerization process after step a) or b) or c) or c) i) a low molecular weight hydrocarbon polymer; Or ii) introducing a metal salt mixture of a hydrocarbon polymer and a higher fatty acid; Method for producing a shock-resistant rubber-modified styrene-based copolymer transparent resin composition excellent in release properties comprising a. The method of claim 5, wherein the low molecular weight hydrocarbon polymer has a viscosity average molecular weight of 500 to 3000, the metal salt of the higher fatty acid is zinc- stearate or magnesium- stearate, the release agent is added directly in the polymerization process at 0.02 to 0.4 parts by weight. Method for producing an impact resistant styrene-based transparent resin composition excellent in releasability. The method of claim 5, The styrene-butadiene copolymer has a 5% styrene solution viscosity of 20 50 cps (centipoise) at 25 ° C. Styrene-based monomers include alkyl styrenes such as styrene, α -methyl styrene, o -methyl styrene, p -methyl styrene, m -methyl styrene, ethyl styrene, i -butyl styrene and t -butyl styrene; And halogenated styrenes such as o -bromo styrene, p -bromo styrene, m -bromo styrene, o -chloro styrene, p -chloro styrene, and m -chloro styrene. The (meth) acrylic acid alkyl ester monomer is at least one member selected from the group consisting of methyl methacrylate, ethyl methacrylate, n -butyl methacrylate, 2-methyl hexyl acrylate and 2-ethyl hexyl acrylate. A method of producing an impact resistant styrene-based transparent resin composition excellent in releasability. The method according to claim 5, wherein the polymerization method of the rubber-modified styrenic copolymer transparent resin is selected from the group consisting of continuous or batch bulk polymerization, solution polymerization and mass-suspension polymerization, impact resistance styrenic copolymer transparent with excellent releasability Method for producing a resin. The method for producing an impact resistant styrene transparent resin having excellent releasability according to any one of claims 5 to 8, wherein the average particle diameter of the rubber particles dispersed in the rubber modified styrene transparent resin is 1.0 µm or less. .