JPS58147435A - Foamable styrene resin composition - Google Patents

Abstract

PURPOSE:To prepare a foamable styrene resin composition having excellent heat resistance, by mixing a foaming agent with a styrene resin containing more than specific amount of a halogenated styrene as a polymer component. CONSTITUTION:A styrene resin containing >=50wt% halogenated styrene (e.g. monochlorostyrene) as a polymer component, is impregnated with 1-20wt% (based on the styrene resin) of a foaming agent (e.g. propane), and if necessary, mixed with a pigment, a flame retardant, an antioxidant, etc. to obtain the objective foamable styrene resin composition. The styrene resin used as the starting raw material can be prepared, e.g. by the aqueous suspension polymerization of a halogenated styrene and a monomer copolymerizable therewith (e.g. styrene). USE:Heat insulation material for solar energy equipment, heat-insulation and structural material for automobile, etc.

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 volatile blowing agents such as pentane, methyl chloride, and dichlorofluoromethane are known as expandable styrenic resins. This expandable styrene resin can be extruded and foam-molded using an extruder, or the particulate resin can be heated with steam to form pre-expanded particles.
It has excellent features such as being able to easily produce a foamed styrenic resin molded body with a gap of 9 by filling the gold layer of the closed layer and heating and foaming it. The molded foam made in this way is used for food containers, slowing materials, insulation materials, floats, etc. However, because the main component is polystyrene resin, it has poor heat resistance and can withstand temperatures of over 100 degrees Celsius. If you keep it for a long time, it will shrink and will not be able to maintain its original shape. Various attempts have therefore been made to improve heat resistance. For example, blends with heat-resistant polymers (lVI
M Publication No. 54-63195, Japanese Unexamined Patent Publication No. 54-63194
Publication No., JP-A No. 52-101268 1% open 185
No. 4-6316@), Improving heat resistance of polymers by non-equimolar copolymerization with maleic anhydride C JP-A-46-55
43, JP 55-112242, JP 55-11540'7, JP 1111855-11
0131 publication, 41I Kaisho 55-112213 publication,
Japanese Unexamined Patent Publication No. 55-115411 1% Unexamined Publication No. 55-117
Publication No. 633).

Use of silicone oil (Japanese Patent Application Publication No. 54-50074)
, addition of a crosslinking agent, etc. However, the foamable resin compositions produced by these methods have drawbacks such as a low expansion ratio, insufficient heat resistance, and a tendency to adhere to equipment.

The present invention solves these problems. That is, 1. the present invention is a foamable styrene-based resin composition comprising a styrene resin and a blowing agent, wherein the #styrenic resin is a component containing 50 weight or more of halogenated styrene. The present invention relates to a resin composition.

The styrenic resin in the present invention is a polymer of halogenated styrene or a copolymer containing halogenated styrene as a main component. Here, halogenated styrene refers to chlorostyrenes such as monochlorostyrene, dichlorostyrene, and trichlorostyrene, bromostyrenes such as monobromostyrene, dipromostyrene, and tribromostyrene, and bromochlorostyrenes such as monobromomonochlorostyrene. Styrene chains, etc. Other polymers that can be copolymerized with halogenated styrene include styrene or α-methylstyrene, substituted styrenes such as vinyltoluene, vinyl cyanide compounds such as acrylonitrile, methyl acrylate, ethyl acrylate, butyl acrylate, and hydroxyl. One or two of acrylic esters such as ethyl acrylate, methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and hydroxyethyl methacrylate, unsaturated carboxylic acid anhydrides such as maleic anhydride, and their mono- or dialkyl esters. The above are used. In addition, in the present invention, the styrenic resin is a polymeric component containing 50 weight or more of halogenated styrene from the viewpoint of the heat resistance 9 surface appearance of the foam, the manufacturing cycle, and the expansion ratio of the foamable styrene resin composition. There is.

The heat resistance of the foam molded article increases as the content of halogenated styrene increases. In addition, in the case of a styrene-chlorostyrene copolymer, if it contains polystyrene and chloromethyl 50 to 0 weight, the temperature is 1O to ls℃.
, 1s~ when containing 70 weight or more of chlorostyrene
20°C heat resistance is improved. Even if the weight of chlorstyrene sO is lower than that of chlorstyrene, the heat resistance properties will improve depending on the proportion, but the difference from polystyrene is not significant. The range in which the heat resistance of the foam is clearly superior to that of polystyrene is when the halogenated styrene content is 50% by weight, and the difference in properties is particularly significant when it exceeds 70% by weight.

The styrenic resin of the present invention can be produced using a widely known polymerization method for vinyl polymers. Komude polymerization method pE', turbid polymerization, bulk polymerization.

Solution polymerization etc. are optional. For example, when using an aqueous suspension polymerization method, the method generally used to produce expandable polystyrene particles can be applied as is.

Suitable polymerization initiators include benzoyl peroxide, dipropenzoyl oxide, dicumyl peroxide, di-tertiary
-butyl peroxide, 25-di(peroxybenzoate)hexyne-3゜1,3-bis(13butylperoxyisoglobil)benzene, lauroyl peroxide, tertiary
-butyl peracetate, λ5-dimethyl-λ5-di(
137'Tylperoxy)hexane-3,215-dimethyl-45-di(tert-butylperoxy)hexane and tert-butylpapene/ate.

There are organic compounds such as methyl ethyl lactone peroxide and methyl cyclohexanone peroxide, and system compounds such as azobis-isobutyronitrile and dimethylazodiinobutyrate, and one or more of these may be used.

The amount used is determined depending on the type of polymerization component and the desired molecular weight of the resulting polymer, but preferably αl-4,0 weight S is used based on the polymerization component.

In the case of aqueous suspension polymerization, S* phosphates, water-soluble polymeric protective colloids, etc. are added to the polymerization system as a dispersant. -Soluble phosphates include tricalcium phosphate and calcium phosphate. Examples of polymeric preservative colloids include water-soluble cellulose derivatives such as boribicellulose and hydroxyalkyl cellulose cellulose, and sodium polyacrylate. -Soluble phosphoric acid- is preferably Fi, α01 based on the amount of substance present in the polymerization system.
In terms of weight, the water-soluble polymeric protective colloid preferably has:
It is used in a range of 0.01-1 weight. In addition, it is possible to add an anionic surfactant and a water-filled inorganic material to the polymerization system.

As a polymerization operation, a polymer prepared in advance may be dissolved in a monomer and then one polymerization may be started.

Particularly in the case of aqueous suspension polymerization, the polymer particles may be suspended in advance, and the monomers may be added to impregnate the particles before being combined. In these cases,
t-2 tylstyrene.

As a polymerization component for polymerization or coalescence, or as a component for nanatsumer.

Based on the total amount of polymer and monomer, it is sufficient to use 50% or more by weight of 0 polymer or □ monomer.

Polymers of monomers that can be used and obtained as raw materials for resins that do not need to be contained in only one of them.
is a copolymer.

Since the blowing agent used in the present invention has the property of not dissolving the styrene resin or only slightly swelling it, its boiling point is lower than the softening point of the polymer produced in 1 above, which is normal. Liquid or gaseous materials 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 1 to 20% heavier than the styrene resin.
Preferably ti3-15 wt. is used. When one of the above blowing agents, pronoin and butane, cannot be used alone or in combination, it is preferable to use a small amount of a solvent necessary to soften the styrene resin to some extent. Examples of such solvents include ethylbenzene, benzene, and toluene. The amount used is α compared to styrene resin.
1 to 4 weights are preferred.

How to impregnate styrene resin with a blowing agent.

Particles of the styrene resin (nine obtained by Jl turbidity polymerization)
or pelletize and suspend 94 in an aqueous medium, and add 9 to this.
Methods include a method of press-injecting a blowing agent, a method of kneading the above styrene resin and a blowing agent, and a method of immersing the styrene resin described in J1' in a blowing agent (liquid). (9) When the above-mentioned styrene resin is obtained by suspension polymerization, a blowing agent can be press-injected during the polymerization, preferably when the polymerization conversion rate is 50% or more and 70% or more.

Here, the 1 polymerization conversion rate is the ratio of the total amount of polymerized styrene resin and monomer to the total amount of styrene resin and monomer at the time of charging (weight). ) means.

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

The foam molded product obtained from the expandable styrenic resin composition according to the present invention has excellent heat resistance. The reason for this is that the thermal softening temperature of the polymer increases due to the use of styrenes.

Although the heat resistance of the foam molded product made from the foamable styrenic resin composition according to the present invention varies slightly depending on the expansion ratio, when compared with molded products using conventional foamable styrene resin, the heat resistance is 9. It has excellent performance in terms of performance.

Applications of the foam obtained from the composition of the present invention include solar insulation materials, automobile insulation structural materials, hot water tank insulation materials, metal tile underlay materials, insulation materials for school lunch containers, insulation materials for vehicles and ships, Hot water pipe insulation material, near conditioner wind body, sun zinc board. Possible options include metal co-formed panels.

“Next, examples of the present invention will be shown.

Example 1 1 portion of ion-exchanged water was placed in a 4-ton autoclave with a rotating stirrer.
500) (100 parts by weight), basic calcium sulfate 2
．． 25P (0.15 parts by weight), dodecylbenzenesulfonic acid) IJF α0451P (α003 parts by weight),
Add and distribute evenly.

Subsequently, styrene 45OP (30 parts by weight) and chlorostyrene 1050t (70 parts by weight) were annealed, and then benzoyl peroxide 2.25PC (0.15 parts by weight) and tert-butyl perbenzoate 0.75% were melted. (Dissolve 0.05 parts by weight and add 9 parts by weight.

While stirring, raise the temperature to 80°C to start polymerization.

The reaction was continued for about 3 hours at 7 tft while maintaining the temperature at 80°C.

After confirming that the specific gravity of the copolymer particles was 1.00 or more using the specific gravity liquid method, ethylbenzene 15P (1.0 parts by weight) was added, and after 20 minutes, butane gas 280% was pressurized with nitrogen gas. . After butane gas injection, the temperature begins to rise again.
After 2 hours, the temperature was increased to 125'C, and the temperature was kept at this temperature for 4 hours.
After nine hours of reaction.

The system was cooled to 30° C. and excess gas in the system was discharged.

Thereafter, it was dried separately by F to obtain particles of a zero-expandable styrenic resin composition. The particles contain a5 weight amount of butane, which is a blowing agent. Particle size α8 obtained by sieving these particles
The particles having a size of 4 to 1,68 cm were pre-foamed with steam and expanded to a bulk ratio of 60 times to obtain pre-foamed particles. Furthermore, the pre-expanded particles were filled in a metal mold and molded in a steam molding machine under certain conditions to obtain a molded article with an excellent surface and good welding. Example 2 A heat resistance test was conducted using this molded body. Styrene was 300P (20 parts by weight) and chlorostyrene was 1200? (80 parts by weight) A foamed molded product was obtained using the same formulation and method as in Example 1 except for the ingredients. A heat resistance test was conducted using this molded body.

Example 3 Without using styrene, chlorostyrene was used at 1500PC1
A foamed molded article was obtained using the same formulation and method as in Example 1, except that 0.00 parts by weight) was used. A heat resistance test was conducted using this molded body.

Example 4 Styrene at 150? (10 parts by weight) and chlorostyrene at 1200? (80 parts by weight), and further using 150f (10 parts by weight) of methyl methacrylate, the same formulation and method as in Example 1 except for 9 were used to form a foamed molded product. Using this molded body, conduct a heat resistance test.

Example 5 Styrene 600? Example 1 except that (40 parts by weight) and 4-bromostyrene were used as 900) (60 parts by weight)
A foamed molded article was obtained using the same formulation and method. Six heat resistance tests were conducted using this molded body.

Comparative Example 1 Using styrene without using chlorostyrene (1500) (10
0 parts by weight) ill! A foamed molded product was produced using the same formulation and method as in Example 1, except that the foam was used. A heat resistance test was conducted using this molded body.

Comparative Example 2 A foamed molded product was obtained using the same formulation and method as in Fi Example 1, except that styrene was used at 1200 t (80 parts by weight) and chlorostyrene was used at 300 P (20 parts by weight). A heat resistance test was conducted using this molded article. Comparative Example 3 Foamed using the same formulation and method as in Example 1, except that styrene was used as 900 (60 parts by weight) and chlorostyrene was used as 601- (40 parts by weight). A molded body was obtained. A heat resistance test was conducted using this molding.

Comparative Example 4 Styrene 1050? (70 parts by weight) and 300 parts of chlorostyrene. (20 parts by weight) and methyl methacrylate 15 (1 (10 parts by weight)) to obtain a foamed molded product using the same formulation and method as in Example 1 except for the addition. Using this molded product, a heat resistance test was carried out. I went.

Heat resistance tests conducted in Examples and Comparative Examples.

10 awx 10cm+x 15cIR molded bodies
The samples were left in an air thermostat at 0°C for 1 hour, and the volume change of each sample was calculated using equation (1) and compared. The heat resistance test results Fi are summarized in Table IK.

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 can be molded to any size from low foaming to high foaming.
g and foam magnification can be selected, and the resulting molded product can be processed in the same manner as conventional foamed polystyrene molded products. 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] L A foamable styrenic resin composition comprising a styrene resin and a blowing agent, wherein the #styrenic resin contains 50 weight or more of halogenated styrene as a polymerization component. Styrenic resin composition. 2. The foamable styrenic resin composition according to claim 1, wherein the styrenic resin is polychlorostyrene.