JPS58147437A - Foamable styrene resin composition - Google Patents

Abstract

PURPOSE:To prepare the titled composition giving a foamed article having excellent heat resistance, by using a styrene resin containing t-butylstyrene as a polymer component. CONSTITUTION:The objective foamable resin composition is composed of a styrene resin containing >=50wt% of t-butylstyrene as a polymer component and 1-20wt%, preferably 3-15wt% (based on the resin) of a foaming agent (e.g. propane, cyclobutane, etc.). The difference of the heat resistance of the foamed article from that of foamed polystyrene becomes remarkable when the t-butylstyrene-content of the composition is >=70wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foamable styrenic resin composition with excellent heat resistance.

Conventionally, propane and butane were used for styrene resin.

Those containing easily volatile blowing agents such as pentane, methyl chloride, and dichlorofluoromethane are known as expandable styrenic resins. This foamable styrene-based resin can be extruded and foam-molded using an extruder, and one particle can be heated with steam, made into pre-expanded particles, and filled into a mold of a closing machine and heated. It has excellent features such as being able to easily produce molded cellular styrenic resin products. Nine molded foams made in this way are used as food containers, cushioning materials.

It is used for insulation materials, floats, etc., but because the main component is polystyrene resin, it has poor heat resistance.

If kept at a temperature of 100°C or higher for a long time, it will shrink and will not be able to maintain its original shape. Therefore, various attempts have been made to improve heat resistance. For example, blends with heat-resistant polymers (% Japanese Patent Application Laid-open No. 54-63195,
01268, JP-A-54-6316), improvement of heat resistance of polymers by non-equimolar copolymerization with maleic anhydride (% JP-A-46-5543).

JP-A-55-112242, JP-A-55-115
407, JP 55-110131, JP 55-112213, JP 55-11541
1 Publication, 41 Publication No. 117633/1983), Use of silicone oil (41 Publication No. 54-50074), 1
1) Addition of a bridging agent causes problems. .

However, Marumi foaming resin compositions made using these methods,
It has disadvantages such as insufficient heat resistance, inability to increase the expansion ratio (9), and easy adhesion to gold (11).

The present invention solves these problems.

That is, the present invention provides a foamable styrenic resin composition comprising a styrene resin and a blowing agent, in which the styrenic resin contains t-butylstyrene as a polymerization component.
The present invention relates to a foamable styrenic resin composition containing at least 0% by weight.

The styrenic resin in the present invention is polyt-7'f
It is a copolymer whose main component is t-butylstyrene or t-butylstyrene. Other monomers copolymerizable with t-butylstyrene include:

Substituted styrene of styrene mataha α-methylstyrene vinyl toluenate, vinyl cyanide compounds such as acrylonitrile, methyl acrylate, ethyl acrylate,
Butyl acrylate.

Acrylic acid esters such as hydroxyethyl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, unsaturated carboxylic acid anhydrides such as maleic anhydride, mono- or dialkyl esters thereof, or one type thereof; Two or more types are used.

In the present invention, the styrene resin has a heat resistance of 9.
In view of the surface appearance, production cycle, and expansion ratio of the expandable styrenic resin composition, it is necessary to contain 50 weight or more of t-butylstyrene in the polymerization component.

No literature has been found that discloses the use of a styrenic resin containing one polymeric component t-butylstyrene gold as a resin component of a foamable styrenic resin composition in order to obtain a foam with excellent heat resistance. For example, as a raw material for the resin component of a foamable styrenic resin composition, "nuclear alkylated styrene" (Publication No. 41-24267) and "styrene derivative" (Publication No. 49-19106) are used.

(Japanese Patent Publication No. 49-19107), "vinyl aromatic monomer" (% Kokai No. 55-115406 1% Kokai No. 55-115406)
5-115407), etc., but
These documents do not specifically exemplify t-butylstyrene, and furthermore, there is no disclosure regarding the heat resistance of st-butylstyrene and foam.

The present invention relates to a foamable styrenic resin composition that uses such a t-butylstyrene polymer or a copolymer containing t-butylstyrene as a main component and can be made into a round foam with excellent heat resistance. .

Is the heat resistance of foam molded products due to t-butyl styrene in styrene resin? ! It increases as the content increases. For example, in the case of a styrene-1-butylstyrene polymer combination, when it contains polystyrene and a ratio of 50 to 70% by weight of t-butylstyrene, the temperature is 10 to 15℃.
When it contains 1i1* or more, the heat resistance at 15 to 20°C is improved. Even if the amount of t-butylmethylphate is less than 50% by weight, the heat resistance properties will improve depending on the ratio, but the difference from polystyrene is not significant. The heat resistance properties of the foam are clearly superior to those of polystyrene when the t-butylstyrene content is 50i1i1% or more, and the difference in properties is particularly remarkable when the content is 70wtcs or more.

The styrenic resin of the present invention can be produced by any method such as widely known solution polymerization. Even if an aqueous suspension polymerization method is used, the general method for producing expandable polystyrene particles can be applied as is.

Suitable polymerization initiators include bency peroxide K, A
Dichlorobenzoyl llide, dicumyl peroxide, di-tert-butyl peroxide.

2.5-di(peroxybenzoate)hexyne-3,
1,3-bis(tert-butylberoxifisoglobil)benzene, lauroyl peroxide, tert-butyl peracetate, λ5-dimethyl-λ5-di(tert-butylperoxy)hexyne-3, s-5-dimethyl-&5 - Di(tert-butylperoxy)hexane and 1113-butyl perbenzoate, organic compounds such as methyl ethyl ketone peroxide, methylcyclohexanone peroxide, and azo compounds such as azobis-isobutyronitrile and dimethylazodiisobutyrate. , one or more of these can be used. The amount to be used is determined depending on the type of polymerization component and the desired molecular weight of the resulting polymer, but is preferably 0.1 to
ζO weight is used.

In the case of aqueous suspension polymerization, 1 dispersant is 1 soluble/
Add acid salts, water-soluble polymer protective colloids, etc. to the polymerization system. - Examples of soluble phosphates include tricalcium phosphate and magnesium phosphate. Polyvinyl alcohol, alkyl cellulose, ? These include water-soluble cellulose derivatives such as nitroxyalkylcellulose and carboxyalkylcellulose, and sodium polyacrylate. The soluble phosphate salt is preferably used in an amount of 0.01 weight or more, and the water-soluble polymeric colloid is preferably used in an amount of 0,000 to 1 weight, based on the total amount of substances present in the polymerization system. Other breast ionic surfactants.

Water-soluble inorganic groups can be added to the polymerization system.

As a polymerization operation, a pre-produced polymer is used as a polymer! The zero polymerization may be started after the polymerization is completed.

In order to carry out aqueous suspension polymerization, the polymer particles may be suspended in advance, and a monomer may be added to impregnate the core particles with the monomer, followed by polymerization. In these cases,
t-butylstyrene.

The polymerization component of the polymer is used as a component of nanatsuma.

It is sufficient that it is used in an amount of 50% or more based on the total amount of the polymer and monomer, and it does not need to be contained in only either the polymer or the monomer. It should be noted that the polymer here refers to a heptad polymer or copolymer that can be used as a raw material for the styrene resin of the present invention.

The blowing agent used in the present invention is a round one that does not dissolve the styrene resin or slightly swells the styrene resin.
Those having a boiling point lower than the softening point of the above-mentioned produced polymer and which are normally liquid or gaseous can be used. For example, propane.

These include aliphatic hydrocarbons such as butane and pentane, and cyclic aliphatic hydrocarbons such as cyclobutane and cyclopentane. The blowing agent is used in an amount of 1 to 20% by weight, preferably 3 to 15% by weight, based on the styrene resin. Among the above-mentioned blowing agents, when Gropa/and butane are used alone or in combination, it is preferable to use a small amount of a solvent necessary to soften the styrenic resin to some extent. As such solvent N! Examples include d-ethylbenzene, benzene, and toluene. The amount used is 0.1 to 4 per styrene resin.
Light weight is preferred.

How to impregnate styrene resin with a blowing agent.

A method of suspending particles (obtained by suspension polymerization) or pellets of the styrenic resin in an aqueous medium and pressurizing a blowing agent into the suspension; a method of kneading the above styrenic resin and a blowing agent. There is a method in which the above styrene resin is immersed in a foaming agent (liquid). Further, when the above-mentioned styrene resin is obtained by suspension polymerization, a blowing agent can be press-injected during the polymerization, preferably at a point when the polymerization conversion rate is 50 or more, particularly 7096 or more. When monomers are polymerized in the presence of styrene resin, it means the ratio of the total amount of styrene resin and monomer other than polymerization to the total amount of styrene resin and monomer at the time of charging (weight 916). do.

Note that the resin particles according to the present invention may contain known additives such as pigments, fuel agents, antioxidants, and antistatic agents.

The foam molded article obtained from the expandable styrenic resin composition according to the present invention has excellent heat resistance. The reason for this is the rounding off of the increase in the thermal softening temperature of the polymer due to the use of [-butylstyrene.

The heat resistance of the foamed molded product made from the foamable styrenic resin composition according to the present invention differs depending on the expansion ratio, but compared to molded products made using conventional foamable styrene resin. case.

It has excellent heat resistance and excellent performance.

The uses of the foam discovered by the composition of the urine invention include solar power, heat insulating materials, insulation structural materials between automobiles,
Insulation materials for hot water tanks, metal tile underlay materials, insulation materials for school lunch containers, insulation materials for wheeled vessels, insulation materials for hot water pipes, near-conditioner wind barrels, cylindrical boards.Metal simultaneous molding panels, etc. can be considered. ``'Next, examples of the present invention will be shown.

Example 1 1 part of ion-exchanged water was placed in a 4-ton autoclave with a stirring agitator.
500? (100 weight m, basic calcium phosphate 1
2510.15 parts by weight), sodium dodecylbenzenesulfonate 0.045? (0,003 parts by weight) and uniformly dispersed, followed by Styrene 450F (30 parts by weight) and t-butylstyrene 1050? (70 parts by weight) was dissolved.

Next, benzoyl peroxide & 75fP (0.25 parts by weight), tertiary butyl perpenzoate) (0.75) (
Dissolve O, OS (parts by weight) and add a friend.

While stirring, the temperature was raised to 80-°C to start polymerization.

The reaction continued for about 3 hours while maintaining the temperature at 80°C. After confirming by the specific gravity liquid method that the specific gravity of the copolymer particles was 1.00 or more, ethylbenzene 15% was added. (1.0 parts by weight)
Twenty minutes after the addition, butane gas 280R1 was injected under pressure with nitrogen gas. After the butane gas injection was completed, the temperature began to rise again, and 2
After an hour, the mixture was heated to 125°C and the reaction was continued for 4 hours while maintaining this temperature until 90 days.

After cooling for 30 minutes, excess gas in the system was discharged.

Thereafter, it was dried separately to obtain particles of 9 expandable stibine resin compositions. The particles contain &5% by weight of butane, which is a blowing agent. The particle size obtained by sieving these particles is 0.8
4 to 1.68- were pre-foamed with steam and expanded to a bulk ratio of 60 times to obtain pre-foamed particles. Furthermore, fill the mold with pre-expanded particles.

Molding is performed using a steam molding machine under certain conditions.

A molded article with a beautiful surface and good fusion bonding was obtained. A heat resistance test was conducted using this molded body.

Example 2 A foam molded product was obtained using the same formulation and method as in Example 1, except that styrene was changed to 3002 (20 parts by weight) and 1-butylstyrene was changed to 120 (1 (80 parts by weight)). A heat resistance test was conducted.

Example 3 Without using styrene, t-butylstyrene was added at 150 (1
(100 parts by weight) The same formulation as in Example 1 except that
A foamed molded product was obtained by this method. A heat resistance test was conducted using this molded body.

Example 4 Styrene T-15 (1 (10 parts by weight) and t-butylstyrene T-1200? (80 parts by weight) Toshi.

Furthermore, a foamed molded product was obtained using the same formulation and method as in Example 1, except that methyl methacrylate 151' (10 parts by weight) was used. A heat resistance test was conducted using this molded body.

Comparative Example 1 Styrene was used without using t-butylstyrene (1500) (
A foamed molded article was obtained using the same formulation and method as in Example 1, except that 100 parts by weight) was used.

A heat resistance test was conducted using this molded body.

Comparative Example 2 A foam molded product was obtained using the same formulation and method as in Example 1 except for using 120 (1 (80 parts by weight)) styrene and 300F (20 parts by weight) t-butyl styrene.This molded product A heat resistance test was conducted using

Comparative Example 3 900p (60 parts by weight) of styrene and 600p (60 parts by weight) of t-butylstyrene. A foamed molded product was prepared using the same formulation and method as in Example 1, except that the amount was changed to (40 parts by weight). A heat resistance test was conducted using this molded article.

Comparative Example 4 Styrene 1050? (70 parts by weight) and 300% t-butylstyrene. (20 parts by weight).

Furthermore, methyl methacrylate 1-15 (1 (10 parts by weight)
A foamed molded article was obtained using the same formulation and method as in Example 1, except that f was used. Use this molded body.

9. Perform a heat resistance test.

Nine heat resistance tests were conducted in Example 2 and Comparative Example.

10 equipment x 10 I? The molded tubes of F7IXZSα were left in an air constant temperature bath at 100° C. for one week, and the changes in volume of each sample were determined by formula m and compared. The heat resistance test results are shown in Table 1, labeled as i.

The expandable styrenic resin composition according to the present invention is as follows.

It can be molded in the same way as conventional foamable styrene resin. In other words, it can be molded using conventionally known molding methods, and the expansion ratio can be arbitrarily selected from low foaming to high foaming, and the resulting molded product is similar to conventional foamed polystyrene molded products. It is possible to process In addition, it is stable against heat, and unlike conventional foamed polystyrene resin, it does not shrink even when heated to high temperatures.

Claims (1)

[Scope of Claims] 1. In a foamable styrenic resin composition containing a styrene resin and a foaming agent, a foaming material in which the #styrene resin contains t-butyl styrene/ as a polymerization component at least 50% by weight styrenic resin composition. λ The expandable styrenic resin composition according to claim 1, wherein the styrenic resin is polyt-butylstyrene.