JPS593482B2 - Manufacturing method of guard-resistant resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an impact-resistant styrenic resin that has good heat resistance, an excellent balance between impact resistance and fluidity, and particularly excellent impact strength.

Styrenic resins are hard and brittle, so impact-resistant styrenic resins are produced by blending rubber-like elastic bodies and styrene-based resins, or by polymerizing styrene monomers in the presence of rubber-like elastic bodies. It has been improved by methods.

Usually, impact-resistant styrene resin is used in industrial fields such as light electrical equipment, office equipment, and miscellaneous goods, specifically in the housings of televisions, radios, cleaners, air conditioners, etc. by injection molding. .

Recently, in the field of injection molding, especially in the field of large molded products, a high quality balance is required for impact-resistant styrenic resins, such as heat resistance, good flowability, and high impact resistance. There have been various proposals for improving the individual properties of styrenic resins, but none of them are necessarily satisfactory as a method to obtain impact-resistant styrenic resins with a good balance of quality and quality. Ta.

As is well known, to improve the impact resistance of styrene resin,
This can be obtained by increasing the content of rubbery elastic material, but as the content of rubbery elastic material increases, the viscosity of the styrenic monomer solution gradually increases significantly, making it difficult to stir the polymerization solution in industrial production. Or it is unfavorable from the point of view of transportation.

Moreover, when producing by a bulk-suspension polymerization method, it is not preferable because the dispersion stability during suspension polymerization is inhibited. In addition, from the viewpoint of physical properties, impact-resistant styrene-based resins with a high content of rubber-like elastic material have significantly lower rigidity, that is, tensile strength and bending strength, resulting in weak resins, so the balance of physical properties is difficult. Up,
Undesirable. In addition, in order to improve moldability, it is well known to add internal lubricants such as white mineral oil, esters such as butyl stearate, stearyl stearate, etc., but if a large amount of these is added, heat resistance A decline in sexuality is inevitable. The present invention aims to solve these drawbacks by using a specific rubbery polymer and an organic peroxide initiator selected from two specific groups.
The polymer obtained by adding it at the appropriate polymerization time has a high balance of physical properties in terms of impact resistance, heat resistance, fluidity, and moldability, and is an impact-resistant styrene with particularly excellent impact resistance. The purpose of the present invention is to provide a method for producing a resin-based resin.

That is, in the present invention, 2 to 20 parts by weight of polybutadiene having 90 mol% or more of cis-1,4 bonds is dissolved in 80 to 98 parts by weight of a styrene monomer, (100 parts by weight) When polymerizing this, 1 part of the organic peroxide represented by the following structural formula (1X2) (3) was added until the polymerization rate of styrene monomer reached 25 (:! and one or more organic peroxides selected from group (4) below, and then, when the polymerization rate of the styrenic monomer is between 5 and 40%, the following structural formula (2) is added. )
It is characterized in that at least one bifunctional organic peroxide represented by (3) is added and polymerized. However, in the formula, R1 and R2 are the same or different methyl groups, ethyl groups, or phenyl groups, R3 and R4 are the same or different alkyl groups, R5 is an alkylene group, and R6 is an alkoxycarbonyl group.

(Group A) Tertiary butyl peroxyacetate,
Ditertiary butyl peroxy azelate, ditertiary butyl peroxy isophthalate, 1,4 bis(
tertiary-butylperoxycarbonyl) cyclohexane, tertiary-butylperoxy-3,5,5-trimethylhexanoate, and tertiary-butylperoxybenzoate.

The present invention will be explained in more detail below.

In the present invention, polybutadiene having 90 mol % or more of cis 1,4 bonds (hereinafter referred to as high cis polybutadiene) is used as the rubbery polymer.

In general, polybutadiene is preferable because it provides an impact-resistant styrenic resin with excellent low-temperature impact resistance compared to styrene-butadiene copolymer rubber used for the same purpose. However, if polybutadiene with a low cis-1,4-bond is used, and the moldability is at the same level,
Impact resistance is poor, and if the impact resistance is the same, the physical properties are unbalanced, such as poor moldability. In the present invention, the high cis polybutadiene is 2 to 20 parts by weight, preferably 4 to 1 part by weight.
0 parts by weight are dissolved in a styrene monomer and distributed so that the total amount is 100 parts by weight to obtain a polymerization raw material.

If the amount of polybutadiene is less than 2 parts by weight, practically satisfactory impact resistance cannot be obtained, and if it exceeds 20 parts by weight, the viscosity increases as described above, causing problems in production. As the styrenic monomer to be used for polymerization by dissolving the polybutadiene, styrene α-methylstyrene, vinyltoluene, t-butylstyrene, etc. may be used alone or in mixtures, and acrylonitrile, methyl methacrylate, etc. Mixtures of styrenic monomers and copolymerizable monomers may also be used.

Using the styrene monomer solution of high cis polybutadiene thus obtained as a raw material, polymerization is carried out by a bulk polymerization method, a bulk suspension polymerization method, a solution polymerization method, or the like.

In the present invention, at this time, at a specific polymerization time,
First, one or more organic peroxides selected from structural formulas (1), (2), and (3) and one or more organic peroxides selected from group A are added, and then, the structural formula (2X3 ) One main feature is the addition of at least one difunctional organic peroxide selected from the following. The organic peroxides of the structural formulas (1), (2), and (3) and (to) group are used at the initial stage of polymerization, that is, when the polymerization rate of the styrenic monomer is 0 to 25%, preferably 5 to 1%.
Add between 0%. If added after the polymerization rate exceeds 25%, the resulting resin will not have sufficient impact resistance. On the other hand, the bifunctional organic peroxides represented by structural formulas (2) and (3) include ditertiary butyl peroxide, dicumyl peroxide, ditertiary amyl peroxide, and organic peroxides represented by structural formula (1). peroxide, tert-butyl cumyl peroxide, etc., and organic peroxides represented by structural formula (2) include 2,2 di-tert-butyl peroxybutane, 2,2 di-tert-butyl peroxide, etc. 4-methylpentane, 3,3 ditertiary butyl peroxyheptane, 2,2 ditertiary butyl peroxyoctane, etc., and the organic peroxide of structural formula (3) is 4,4 ditertiary butyl peroxyheptane. Peroxyvaleric acid normal butyl ester, 3,
3-ditertiary butyl peroxybutyl acid ethyl ester and the like. The polymerization rate of the styrenic monomer is between 5 and 40 (: fl), preferably between 15 and 30%,
Add at least one of them.

If it is added before it reaches 5%, the impact strength, especially the falling weight strength, will be weak and if it is added after it exceeds 40%, the fluidity will decrease, so the balance between impact resistance and fluidity that is the objective of the present invention will not be met. Excellent styrenic impact resistant resin cannot be obtained.

In the present invention, structural formula (1) (2X3) and (AWf
The organic peroxide of structural formula (2
Add the difunctional organic peroxide of X3).

If the organic peroxides of structural formulas (2) and (3) are added first, a styrenic impact-resistant resin with excellent impact strength cannot be obtained. The amount of these organic peroxides to be added is 3.times.10@-5 to 6.times.10@-4 mol, preferably 6.times.10@-5 to 3.times.10@-4 mol, based on the styrene monomer.

If the amount is less than 3 x 10-5 mol, the substantial addition effect will be poor, and if it exceeds 6 x 10-4 mol, the polymerization rate will become excessive and control of the reaction will become difficult.

In the present invention, the polymerization temperature is preferably in the range of 80 to 150 DEG C. If it is less than 80 DEG C., it will take a long time to obtain the desired styrenic impact resistant resin with an excellent balance of physical properties. If the temperature exceeds 150°C, the reaction rate becomes excessive and it becomes difficult to control the polymerization in a circular manner.

As explained above, the present invention polymerizes a styrene monomer solution in which a specific rubber polymer is dissolved by adding a specific organic peroxide in portions at specific polymerization times, thereby improving heat resistance and impact resistance. It is characterized by producing an impact-resistant styrenic resin with an excellent balance of physical properties such as elasticity and fluidity.As mentioned above, in order to improve one of these physical properties, white mineral oil, etc. Methods in which excessive amounts of plasticizers or molecular weight regulators such as mercaptans were added impair the balance of the physical properties described above, but the method of the present invention can improve the It is of course possible to use conventional amounts of additives, for example, for the same heat resistance, it is possible to use impact-resistant styrenic resins that have a better balance of other physical properties such as fluidity and impact resistance than conventional methods. is obtained.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 25 kg of a styrene solution in which 1.75 kg of high-cis polybutadiene (trade name: "Ube Ball BRl5" manufactured by Ube Industries, Ltd., 97.5% of cis-1,4 bonds) was dissolved in an autoclave with a capacity of 30 j and 2,2 ditercia 7.59 g of l-butyl peroxybutane and 5 g of cyclohexane were added and stirred at 180 rpm.

After replacing the inside of the autoclave with nitrogen gas, the autoclave was sealed and the temperature was raised. After polymerizing at 100° C. for 4 hours, the mixture was cooled to complete the preliminary polymerization.

The polymerization rate of the preliminary polymerization solution at this point was 26.2%. Next, the capacity is 501! 25k pure water in autoclave
f1, sodium dodecylbenzenesulfonate 0.25
g, add 200g of tertiary calcium phosphate, 150rp
While stirring at m, add 3,3 ditertiary butyl peroxybutyl acid ethyl ester 2
The above prepolymerization solution to which 7.5f1 had been added was added, the tube was replaced with nitrogen, the tube was sealed, and the temperature was raised. Polymerization was carried out at a temperature of 115.degree. C. for 5 hours and 135.degree. C. for 4 hours, and then cooled.

After neutralization, dehydration, and drying according to a conventional method, the polymer was extruded into a conventional pellet shape to obtain an impact-resistant polystyrene resin. These conditions and physical property measurement results are
Shown in the table. Example 2 The same operations as in Example 1 were performed except for the following points, and the first
The impact-resistant polystyrene resin shown in the table was obtained.

That is, 5 g of ditertiary butyl peroxide instead of 2,2 ditertiary butyl peroxybutane,
Using di-tert-butyl peroxyazelate 7.59 instead of 1,4-bis(tert-butylperoxycarbonyl)cyclohexane, 4
Time prepolymerization was carried out. The polymerization rate was 27.1%. Using this prepolymerization solution, 3,3 ditertiary butyl peroxybutyl acid ethyl ester 12.
Polymerization was carried out using 25 g of 51 and 3,3 ditertiary butyl peroxyheptane at a temperature of 110°C for 5 hours and 135°C for 4 hours. Example 3 In Example 1, 4,4 ditertiary butyl peroxyvaleric acid n-butyl ester 7 was used instead of 2,2 ditertiary butyl peroxybutane.
．． Prepolymerization was carried out at 105° C. for 5 hours using tertiary-butyl peroxyacetate 109 instead of 5 g of 1,4-bis(tertiary-butylperoxycarbonyl)cyclohexane.

The polymerization rate was 28.0%. Using this prepolymerization solution,
Using 30 g of 4,4 ditertiary butyl peroxybutyl acid n-butyl ester instead of 3,3 ditertiary butyl peroxybutyl acid ethyl ester, the temperature was 110°C for 2 hours, and the temperature was 115°C.
The same procedure was followed except that polymerization was carried out for 2 hours and at 135°C for 5 hours. Comparative Example 1 Low cis polybutadiene (trade name Diene 55AS manufactured by Asahi Kasei Corporation, cis 1,4 bond 3) instead of high cis polybutadiene
The same procedure as in Example 1 was carried out except that 2.3%) was used.

Comparative Example 2 The same procedure as in Example 2 was carried out except that only 12.5 g of ditertiary butyl peroxide was used and preheated polymerization was carried out at a temperature of 110° C. for 4 hours to obtain a prepolymerization solution with a polymerization rate of 25.4%. Summer.

Comparative Example 3 Benzoyl peroxide 70 instead of 3,3 ditertiary butyl peroxybutyl acid ethyl ester
9 and tert-butyl peroxybenzoate 7.5
g at 90°C for 5 hours, 115°C for 2 hours, 130
The same procedure as in Example 1 was carried out except that the polymerization was carried out at ℃ for 3 hours.

Claims (1)

[Scope of Claims] 1. When 2 to 20 parts by weight of polybutadiene having 90 mol% or more of cis-1.4 bonds is dissolved in 80 to 98 parts by weight of a styrene monomer and polymerized, the following structural formula (1),
One or more selected from the organic peroxides represented by (2) and (3) and one or more selected from the organic peroxides of group (A) below are polymerized into styrenic monomers. A styrenic impact-resistant material, which is characterized by adding at least one type of organic peroxide represented by the following structural formulas (2) and (3) and polymerizing it. manufacturing method of synthetic resin. Structural formula (1) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ (2)
▲There are mathematical formulas, chemical formulas, tables, etc.▼(3)▲There are mathematical formulas, chemical formulas, tables, etc.▼(However, in the formula, R_1 and R_2
is the same or different methyl group, ethyl group, phenyl group,
R_3 and R_4 are the same or different alkyl groups, B
_5 represents an alkylene group, and R_6 represents an alkoxycarbonyl group. ) (A) Group tert-butyl peroxy acetate, di-tert-butyl peroxy azelate, di-tert-butyl peroxy isophthalate, 1,4 bis (tert-butyl peroxycarbonyl) cyclohexane, tert-butyl peroxy-3, 5,5 trimethylhexanoate, and tert-butyl peroxybenzoate. 2. The method for producing a styrenic impact-resistant resin according to claim 1, wherein the styrenic monomer is styrene. 3. The amount of organic peroxide added is 3 x 10^-^5 mol or more and 6 x 10^-^4 or less, per 1 mol of gas styrene monomer, as described in claim 1 or 2. A method for producing styrenic impact-resistant resin.