KR20020045937A - Method for preparing styrene resin having macromolecule weight - Google Patents

Abstract

PURPOSE: A method for preparing a styrene-based resin is provided, to increase the molecular weight, to widen the distribution of molecular weight and to reduce the amount of the remaining impurities. CONSTITUTION: The method comprises the steps of mixing 85-95 wt% of a vinyl monomer and 5-15 wt% of a reaction medium to prepare a reaction mixture; adding 0.05-0.1 parts by weight of an organic peroxide initiator selected from the group consisting of organic peroxides having bifunctional group, organic peroxides having tetrafunctional group and their mixtures, to 100 parts by weight of the obtained reaction mixture; and mass polymerizing the mixture. Preferably the mass polymerization is carried out at a temperature of 110-160 deg.C for 4-8 hours.

Description

Manufacturing method of styrene resin having high molecular weight {METHOD FOR PREPARING STYRENE RESIN HAVING MACROMOLECULE WEIGHT}

[Industrial use]

The present invention relates to a method for producing a styrene resin having a high molecular weight, and in particular, to a styrene resin having a high molecular weight comprising the step of bulk polymerization by adding a peroxide initiator to a reaction mixture of a vinyl monomer and a reaction medium. It relates to a manufacturing method.

[Prior art]

Common methods for producing styrene resins include emulsion polymerization, suspension polymerization, and bulk polymerization. In addition, there are a radical polymerization method and an ionic polymerization method depending on the starting method in the polymerization reaction. The radical polymerization method can be prepared simply by simply heating the styrene monomer and the styrene system, the ion polymerization method to produce a styrene resin by heating the styrene monomer and the reaction compound made by adding an initiator such as an organic peroxide or azo compound to the styrene can do.

In view of recent demand trends, the mechanical strength and the heat resistance strength of styrene resins are required to increase, and high molecular weight styrene resins are required to meet such demands. One of the methods for obtaining the high molecular weight styrene resin is a method of increasing the average molecular weight of the styrene resin, which is a high productivity because there is a relationship between the polymerization rate and the average molecular weight of the polymer produced It is difficult to produce styrene resin of high molecular weight. In addition, since styrene resin having a high molecular weight is difficult to process due to poor melt flowability, research on a styrene resin having a high molecular weight and a wide molecular weight distribution is required to improve this.

Due to the above demands, there have been many efforts for the preparation of styrene resin having a high molecular weight, and examples thereof include US Patent Nos. 5,990,255, 4,833,233, 4,137,388, and Korean Patent Registration No. 1984-0001710.

U.S. Patent No. 5,990,255 discloses polymerization of a vinyl acid monomer having a sulfur or phosphorus molecule by mixing with a styrene monomer, or by mixing a peroxide initiator with the vinyl acid monomer and a styrene monomer and then polymerizing a high molecular weight styrene derivative. It was. However, in the case of the former, a styrene resin having a very high weight average molecular weight is manufactured, but because of poor workability, there is a disadvantage in that low molecular weight and high molecular weight must be continuously made to have a bimodal molecular weight distribution. In the latter case, a styrene resin having an appropriate weight average molecular weight is prepared, but there is a problem in that the molecular weight distribution is too narrow and the conversion rate is low compared to the polymerization time.

U.S. Patent No. 4,833,223 is a method of preparing an emulsion polymerization method by mixing a monomer having a multifunctional group with a styrene monomer, and having a weight average molecular weight of about 400,000 to about 900,000, but a molecular weight distribution of 7 to 14 is too wide. There is a problem that seems.

US Pat. No. 4,137,388 discloses a styrene resin prepared by suspension polymerization by mixing organic peroxide-based initiators having different half-lives with styrene monomers, and the styrene resin thus produced showed a weight average molecular weight of about 200,000 to 400,000. However, the method prepared by the suspension polymerization method is required to remove the monomers and reaction medium, organic and inorganic substances other than the initiator added during the polymerization process, and the styrene resin prepared by the above method has a residual impurities of 2000 to 4000 ppm. There is a problem that there are many residual impurities.

Korean Patent Registration No. 1984-0001710 is a method of polymerizing a styrene monomer or a styrene monomer containing a rubbery polymer in a dissolved state by using an organic peroxide as a catalyst, and is prepared by using an organic peroxide having a di- or tri-functional group as an initiator. It was. However, the resin produced by the above method has a problem that the conversion rate is low to 50% by weight or less.

An object of the present invention is to provide a method for producing a styrene resin having a high molecular weight in consideration of the problems of the prior art.

Another object of the present invention is to provide a styrene resin having a high molecular weight, a wide molecular weight distribution, and low residual impurities.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a method for producing a styrene resin comprising the step of polymerizing by adding a peroxide initiator to the reaction mixture of the vinyl monomer and the reaction medium, a mixture of the vinyl monomer and the reaction medium A method of preparing a styrene-based resin having a high molecular weight by the step of bulk polymerization of the mixture by adding an organic peroxide having a bifunctional group, an organic peroxide having a tetrafunctional group, or a mixed organic peroxide initiator thereof to the reaction mixture. To provide.

Hereinafter, the present invention will be described in detail.

[Action]

The present invention relates to a method for preparing a styrene resin prepared by adding a peroxide initiator to a reaction mixture obtained by mixing a vinyl monomer and a reaction medium, and then subjecting the reaction mixture to a mixture of a vinyl monomer and a reaction medium. Styrene resin having high molecular weight, wide molecular weight distribution and low residual impurity by preparing styrene resin by mixing and adding organic peroxide having zero difunctional group, organic peroxide having tetrafunctional group, or mixed organic peroxide thereof and then mass polymerization It provides a method for producing a resin.

In the present invention, in the method for producing a styrene resin comprising the step of polymerization by adding a peroxide initiator to the reaction mixture of the mixture of the vinyl monomer and the reaction medium,

a) mixing the vinyl monomer and the reaction medium to produce a reaction mixture;

b) adding an organic peroxide initiator selected from the group consisting of an organic peroxide having a bifunctional group, an organic peroxide having a tetrafunctional group, and a mixed organic peroxide thereof to the reaction mixture of step a); And

c) bulk polymerizing the mixture of step b)

It provides a method for producing a styrene resin having a high molecular weight comprising a.

More specifically,

The reaction mixture of step a)

V) 85 to 95% by weight of vinyl monomers; And

Ii) 5 to 15% by weight of reaction medium

The organic peroxide initiator of step b) is mixed in a weight ratio of to provide a method for producing a styrene-based resin having a high molecular weight is added to 0.05 to 0.1 parts by weight based on 100 parts by weight of the reaction mixture of step a).

The bulk polymerization of step c) is to perform polymerization at a temperature of 110 to 160 ° C. for 4 to 8 hours, more specifically, to perform polymerization at a temperature of 110 to 140 ° C. for 2 to 4 hours, and then to 120 to 160 It consists of two stages which carry out further polymerization for 2 to 4 hours at a temperature of ℃.

The a) iii) vinyl monomers are styrene, α-methylstyrene, and derivatives having one or more additional substituents in the benzene nucleus (p-bromostyrene, p-methylstyrene, p-chlorostyrene, o-bromostyrene It is preferable to select at least 1 type from the group which consists of

The a) ii) reaction medium may be at least one selected from the group consisting of ethylbenzene, toluene, and xylene, preferably ethylbenzene.

The organic peroxide having the bifunctional group in step b) is 1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane, 1,1-bis (t-butyl peroxy) cyclo It is preferable to select at least one member from the group consisting of hexane and 1,1-bis (t-butyl peroxy) 2-methyl cyclohexane.

The organic peroxide having the tetrafunctional group in step b) is preferably 2,2-bis (4,4-di-t-butyl peroxy cyclohexyl) propane.

In the present invention, an organic peroxide initiator selected from the group consisting of an organic peroxide having a bifunctional group, an organic peroxide having a tetrafunctional group, and a mixed organic peroxide thereof is added to a reaction mixture obtained by mixing a vinyl monomer and ethyl benzene, and then 110 to 140 ° C. The mass polymerization was carried out for 2 to 4 hours at a temperature of 2 to 4 hours, and then further mass polymerization for 2 to 4 hours at a temperature of 120 to 160 ° C. to prepare a styrene resin having a high molecular weight, a wide molecular weight distribution, and low residual impurities. can do.

Styrene-based resin prepared through the production method of the present invention preferably has a high molecular weight of 400,000 or more, the molecular weight distribution is 2.4 or more and the amount of residual impurities is 1000 ppm or less.

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

EXAMPLE

Example 1

In a 1 L batch reactor, 95% by weight of styrene monomer and 5% by weight of ethylbenzene as reaction medium are mixed, and 1,1-bis (t-butyl peroxy) -3, an organic peroxide having a bifunctional group as an initiator, 3,5-trimethyl cyclohexane was added at 0.05 parts by weight based on 100 parts by weight of the reaction mixture. The reaction mixture was bulk polymerized for 2 hours at a temperature of 110 ° C., and further bulk polymerized for 2 hours at a temperature of 140 ° C. to prepare a styrene resin.

Example 2

1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane which is an organic peroxide having a bifunctional group as an initiator and 2,2-bis (4,4- which is an organic peroxide having a tetrafunctional group A styrene resin was prepared in the same manner as in Example 1, except that di-t-butyl peroxy cyclohexyl) propane was added in an amount of 0.05 parts by weight based on 100 parts by weight of the mixture by mixing 67% by weight and 33% by weight, respectively. It was.

Example 3

1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane which is an organic peroxide having a bifunctional group as an initiator and 2,2-bis (4,4- which is an organic peroxide having a tetrafunctional group A styrene resin was prepared in the same manner as in Example 1, except that di-t-butyl peroxy cyclohexyl) propane was mixed at 50% by weight and 50% by weight, respectively, and added at 0.05 part by weight based on 100 parts by weight of the reaction mixture. It was.

Example 4

1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane which is an organic peroxide having a bifunctional group as an initiator and 2,2-bis (4,4- which is an organic peroxide having a tetrafunctional group A styrene resin was prepared in the same manner as in Example 1, except that di-t-butyl peroxy cyclohexyl) propane was mixed at 33 wt% and 67 wt%, respectively, and added at 0.05 wt part based on 100 wt part of the reaction mixture. It was.

Example 5

Example 1 except that 2,2-bis (4,4-di-t-butyl peroxy cyclohexyl) propane, an organic peroxide having a tetrafunctional group as an initiator, was added in an amount of 0.05 parts by weight based on 100 parts by weight of the reaction mixture. In the same manner as in the styrene resin was prepared.

The molecular weight and powder distribution of the styrene resins obtained in Examples 1 to 5 were measured, and the results are shown in Table 1 below.

TABLE 1

division Example 1 Example 2 Example 3 Example 4 Example 5 Number average molecular weight 159,227 160,131 157,014 159,318 161,502 Weight average molecular weight 407,988 410,533 431,745 455,313 489,129 Molecular weight distribution 2.56 2.56 2.75 2.86 3.03 Yield (wt%) 85.6 89.3 71.7 78.6 73.5 Residual impurities (ppm) 770 780 910 830 810

Through Table 1, it was confirmed that the styrene resins of Examples 1 to 5 manufactured by the production method of the present invention have a high molecular weight of 400,000 or more, a molecular weight distribution of 2.4 or more, and an amount of residual impurities of 1000 ppm or less.

In the production method of the present invention, a styrene-based resin having a high molecular weight and having a wide molecular weight distribution and low residual impurities can be prepared.

Claims (10)

In the method for producing a styrene resin comprising the step of polymerization by adding a peroxide initiator to the reaction mixture of the vinyl monomer and the reaction medium, a) mixing the vinyl monomer and the reaction medium to produce a reaction mixture; b) adding an organic peroxide initiator selected from the group consisting of an organic peroxide having a bifunctional group, an organic peroxide having a tetrafunctional group, and a mixed organic peroxide thereof to the reaction mixture of step a); And c) bulk polymerizing the mixture of step b) Method for producing a styrene resin having a high molecular weight comprising a. The method of claim 1, The reaction mixture of step a) V) 85 to 95% by weight of vinyl monomers; And Ii) 5 to 15% by weight of reaction medium Method for producing a styrene resin having a high molecular weight mixed in a weight ratio of. The method of claim 1, The organic peroxide initiator of step b) is a method for producing a styrene resin having a high molecular weight added to 0.05 to 0.1 parts by weight based on 100 parts by weight of the reaction mixture of step a). The method of claim 1, The mass polymerization of step c) has a high molecular weight styrene-based polymerization to perform polymerization for 4 to 8 hours at a temperature of 110 ~ 160 ℃. The method of claim 1, The bulk polymerization of step c) After the polymerization is carried out for 2 to 4 hours at a temperature of 110 to 140 ℃, the method of producing a styrene resin having a high molecular weight to further polymerize for 2 to 4 hours at a temperature of 120 to 160 ℃. The method according to claim 1 or 2, Styrene) having a high molecular weight selected from the group consisting of styrene α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene and o-bromostyrene Method for producing a resin. The method according to claim 1 or 2, And a) ii) a method for producing a styrene resin having a high molecular weight selected from the group consisting of ethylbenzene, toluene and xylene. The method according to any one of claims 1 to 3, The organic peroxide having the bifunctional group in step b) is 1,1-bis (t-butyl peroxy) -3,3,5-trimethyl cyclohexane, 1,1-bis (t-butyl peroxy) cyclo A method for producing a styrene resin having a high molecular weight selected from the group consisting of hexane and 1,1-bis (t-butyl peroxy) 2-methyl cyclohexane. The method according to any one of claims 1 to 3, The method for producing a styrene resin having a high molecular weight, wherein the organic peroxide having the tetrafunctional group in step b) is 2,2-bis (4,4-di-t-butyl peroxy cyclohexyl) propane. The method of claim 1, The styrene resin has a high molecular weight of 400,000 or more, a molecular weight distribution of 2.4 or more, and an amount of residual impurities of 1000 ppm or less.