JPH10176078A - Expandable resin particle and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject particle capable of manifesting good expansibility and processability and providing a highly heat-resistant expansion molding product by using a specific (meth)acrylic ester and a polymerizable group- containing silane compound in combination as a monomer component. SOLUTION: This expandable resin particle is produced by impregnating (A) a polymeric particle, prepared by carrying out the suspension polymerization of a monomer component containing (A1 ) 50-95wt.% styrene-based monomer, (A2 ) 5-50wt.% tricyclo[5.2.1.0<2> ,<6> ]dec-8-yl (meth)acrylate and (A3 ) a polymerizable functional group-containing silane [e.g. a compound represented by the formula X-Si-Yn -Zm X is an organic group having a copolymerizable double bond such as 3-methacryloxypropyl; Y is a hydrolyzable group such as methoxy; Z is an inert monovalent organic group; (n) is 1-3; (m) is [3-(n)]}] in an amount of 0.1-5wt.% based on the total amount of the components A1 and A2 with (B) a readily volatile foaming agent (e.g. propane, butane or pentane).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to expandable resin particles from which a foamed article having high heat resistance can be obtained, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, expandable styrene resin particles are often used as expandable plastics suitable for foam molding. However, foamed molded products made from expanded styrene-based resin particles have poor heat resistance, so they are used in applications requiring heat resistance higher than the softening temperature of styrene-based resins, such as hot water insulation materials and metal roof insulation in construction. I couldn't do it.

[0003] Many attempts have been made in the past to improve the heat resistance of foamed molded products, but many of them have been proposed to improve the heat resistance of the foamed molded article by improving the heat resistance of the resin itself. Therefore, the molding temperature and the heat-resistant temperature were close to each other, and it was difficult to impart high foaming properties. Further, each of the proposed heat resistant resins has an inherent problem due to the resin composition. For example, Japanese Patent Application Laid-Open No. 47-39186 proposes a styrene-maleic anhydride copolymer, which requires a complicated suspension polymerization step and a resin component having good adhesiveness to metal. There was a problem with the releasability at the time. Japanese Patent Publication No. 57-182334 proposes a copolymer of methyl methacrylate and α-methylstyrene. However, since the polymerizability of α-methylstyrene is inferior, a long-time polymerization process at a high temperature is required. JP-A-60-20
Nos. 6846, 206847 and 206848 disclose α.
Although copolymers containing methylstyrene and acrylonitrile as main components have been proposed, copolymerization of acrylonitrile lowers the fluidity of the resin, making it difficult to impart high foaming properties. JP 60-115636 Patent styrene and methacrylic acid tricyclo in publication [5,2,1,0 ^2,6] dec-8-yl and / or acrylic acid tricyclo [5,2,1,0 ^2,6] deca A copolymer with -8-yl has been proposed, but is a component for improving heat resistance, tricyclo [5,2,1,0 ^2,6 ] methacrylate-8-yl or tricycloacrylate [5,2,1,0 ^2,6 ] Duka-8-yl is expensive and disadvantageous in terms of cost because it requires approximately 35% by weight or more to give sufficient heat resistance. .

As a method for improving the heat resistance of other expandable styrenic resins, Japanese Patent Publication No. 58-46251 proposes a method of copolymerizing an organic silane compound. Although it was excellent, it was not possible to impart long-term heat resistance that could withstand practical use. Accordingly, the present invention is to provide heat-resistant foamable resin particles having high heat resistance when formed into a foamed product while maintaining high foamability, and having excellent economic efficiency.

[0005]

SUMMARY OF THE INVENTION The present invention can be processed at a lower temperature until the foam molding step, and the crosslinking reaction proceeds by heating in the foam molding step.
The present invention relates to heat-resistant foamable resin particles exhibiting higher heat resistance when formed into a foamed molded product.

[0006] In order to exhibit good moldability, styrene is blended so that the compounding ratio of the component for imparting heat resistance is lower than the target heat-resistant temperature. In addition, a polymerizable functional group-containing silane compound is blended, and after a copolymer is obtained, a silanol group, which is a hydrolyzate of the silane compound, is crosslinked by dehydration condensation in a molding step which is a final step for obtaining a foamed molded article. To obtain a foamed molded product that is more improved than the heat resistance before the molding process, thereby achieving 100%
Even when instantaneously exposed to high temperatures exceeding
An object is to obtain a foam having excellent heat resistance even at a long-term heat resistance at 0 to 100 ° C.

[0007]

SUMMARY OF THE INVENTION The present invention relates to foamable resin particles obtained by impregnating a polymer particle obtained by suspension polymerization with a volatile foaming agent. The component of the monomer is 50% by weight or more and less than 95% by weight of a styrene-based monomer, tricyclo [5,2,1,0 ^2,6 ] dec-8-yl methacrylate and / or tricyclo [5, 2,1,0 ^2,6 ] duka-8-yl in an amount of 5% by weight or more and less than 50% by weight, and a polymerizable functional group-containing silane compound copolymerizable with styrene or the like, based on the total amount of the above monomers The present invention relates to expandable resin particles having a content of 0.1% by weight or more and 5% by weight or less and a method for producing the same.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to have good foamability and processability, a high styrene ratio is required. In other words, the heat resistance improving component is effectively improved in a smaller amount. It is preferable that the compound is a compound capable of forming tricyclo [5,2,1,0 ^2,6 ] dica-8-methacrylate as such a compound.
Yl and / or tricyclo [5,2,1,0 ^2,6 ] acrylate tecca-8-yl have been found to be effective.

A silane compound having a polymerizable functional group, which can be copolymerized with styrene and is crosslinked in a molding step;
For example, 3-methacryloxyfluorotrimethoxysilane was found to be effective. The copolymerization and cross-linking of the polymerizable functional group-containing silane compound are performed in separate steps using the difference between the polymerization temperature and the molding temperature. The introduction into the polymer main chain becomes possible by performing the synthesis temperature in the polymerization step at 80 ° C. to 105 ° C., and the crosslinking reaction proceeds by performing the molding temperature at 110 ° C. to 125 ° C .; When foamability is obtained and a molded product is obtained, a foam having higher heat resistance can be obtained.

The polymerization of the polymerizable functional group-containing silane compound is carried out by
When the degree of polymerization is 40% to 90%, the polymerization is carried out by introducing the compound into the polymerization system. When the degree of polymerization is less than 40%, the dispersion system becomes unstable, so that it is difficult to control the particle diameter. The crosslinking reaction at the time is not so good. Preferably, when the degree of polymerization is 50 to 70%, the particle size control and the crosslinking reaction proceed stably.

The average particle size of the heat-resistant polymer particles according to the present invention is usually 0.05 to 2.0 mm. If the average particle size is outside this range, it tends to be difficult to obtain a stable particle size by suspension polymerization. In order to more stably copolymerize the polymerizable functional group-containing silane compound, it is preferable to introduce the silane compound into the polymerization system in a state of being emulsified with the surfactant used in the polymerization reaction at the above-mentioned polymerization rate.

Here, the styrene monomer means styrene or styrene as a main component, styrene derivatives such as α-methylstyrene, chlorostyrene and vinyltoluene, and acrylics such as methyl acrylate, ethyl acrylate and butyl acrylate. It is a mixed monomer with acid esters, methacrylic esters such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

A conventionally known method can be applied to suspension polymerization of a styrene monomer. The suspension polymerization of a styrene-based monomer is a method in which a styrene-based monomer in which an organic peroxide is dissolved is dispersed in an aqueous medium containing a dispersant, and radicals are generated to perform polymerization. In the present invention, polymer particles can be obtained in the same manner. As a dispersant used in suspension polymerization, a conventionally known method such as a method using a sparingly soluble inorganic salt and a surfactant in combination or an organic dispersant such as PVA can be applied.

As the organic peroxide according to the present invention, conventionally known compounds having a 10-hour half-decomposition temperature of 50 to 120 ° C. can be applied. For example, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy benzoate, t-butyl peroxy isopropyl carbonate, di-t-butyl peroxy hexahydroterephthalate, di-t-butyl peroxy trimethylcyclohexane, bis (di-t-butyl peroxy) (Cyclohexyl) propane and the like. As the chain transfer agent, conventionally known ones such as octyl mercaptan, dodecyl mercaptan, and α-methylstyrene dimer can be used.

The volatile volatile agent is appropriately selected from aliphatic hydrocarbons such as propane, isobutane, normal butane, isopentane, normal pentane and cyclopentane. Further, as a foaming aid, an alicyclic hydrocarbon such as cyclohexane or an aromatic hydrocarbon can be used in addition to the aliphatic hydrocarbon. The impregnation of the polymer particles with the readily volatile foaming agent can be performed during the polymerization or after the polymerization is completed. The amount of the foaming agent to be contained is 0.1 to the total amount of the monomers.
The content is 1% by weight or more and 5% by weight or less. If the amount is less than 0.1% by weight, it is difficult to impart foaming properties, and a foaming agent exceeding 5% by weight is not required and is not economical.

The expandable resin particles according to the present invention are impregnated with a foaming agent, and after being dehydrated and dried, coated with a surface coating agent. As the coating agent, those applied to expandable polystyrene can be applied as they are. For example, zinc stearate, triglyceride stearate, monoglyceride stearate, hardened castor oil, amide compounds, silicones, antistatic agents and the like.

[0017]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. Example 1 <Polymerization reaction> In a 16 liter autoclave attached to a stirrer, 6000 g of pure water, 9 g of 3 calcium phosphate, 0.24 g of sodium dodecylbenzenesulfonate, 0.24 g of sodium sulfate
4.2 g was charged and charged while stirring at 200 rpm. Then, while stirring, styrene 4800
g (80 parts by weight), 1,200 g (20 parts by weight) of tricyclo [5,2,1,0 ^2,6 ] tecca-8-yl methacrylate (manufactured by Hitachi Chemical Co., Ltd .: FA-513M), and 24.0 g of benzoyl peroxide. , T-butyl peroxy isopropyl carbonate 3.0
g, 3.0 g of ethylenebisamide and 150 g of toluene were mixed and dissolved. After completion of the charging, the temperature was raised to 90 ° C. Two hours and three hours after the completion of the temperature increase, 3 g and 6 g of 3 calcium phosphate were added, respectively. Subsequently, the temperature was maintained at 90 ° C. for 1.0 hour, and when the conversion reached about 80%, 3-methacryloxyfluorotrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name KBM-5)
03) 120 g (2 parts by weight) were dispersed in 100 g of pure water and 0.6 g of sodium dodecylbenzenesulfonate, and then introduced into an autoclave. Then, at 90 ° C, 2
After keeping the temperature for 100 hours, the temperature was raised to 100 ° C. and further kept for 4 hours to complete the polymerization reaction. <Impregnation of foaming agent> After the polymerization was completed, while keeping the temperature at 100 ° C, 450 g of butane was injected as a foaming agent, and the temperature was further kept for 8 hours. After that, the mixture was cooled to room temperature and taken out of the autoclave. <Post-treatment> After the taken-out slurry was washed, dehydrated and dried, it was passed through 14 mesh and classified with 22 mesh remaining.
Further, the surface was coated with 0.08% by weight of zinc stearate, 0.05% by weight of castor-hardened oil, and 0.02% by weight of dimethyl silicone to obtain heat-resistant foamable styrene resin particles. Table 1 shows the residual monomer content, expandability, heat resistance of molded products, and the like of the obtained expandable styrene resin particles.

Comparative Examples 1 and 2 Suspension polymerization and impregnation with a blowing agent were carried out in the same manner as in Example 1 except for the items shown in Table 1. The test results are shown in Table 1.

[Table 1]

[0019]

According to the present invention, it is possible to provide an expandable resin particle from which an expanded molded article having high heat resistance can be obtained, and an economical production method thereof.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // (C08F 212/08 220: 18 230: 08)

Claims (6)

[Claims] 1. A polymer particle obtained by suspension polymerization,
In the foamable resin particles obtained by impregnating the volatile volatile foaming agent, the component of the monomer used in the production of the particles is 50% by weight or more and less than 95% by weight of a styrene-based monomer, and tricyclo [methacrylate] is used. 5,2,1,0 ^2,6 ] duka-8-yl and / or tricycloacrylate
[5,2,1,0 ^2,6 ] duka-8-yl in an amount of 5% by weight or more and less than 50% by weight,
And foamable resin particles containing a polymerizable functional group-containing silane compound copolymerizable with styrene or the like in an amount of 0.1% by weight or more and 5% by weight or less based on the total amount of the above monomers. 2. The polymerizable functional group-containing silane compound is represented by the following general formula (I): X-Si-Yn-Zm X = organic group having a double bond capable of copolymerization Y = hydrolyzable group The expandable resin particles according to claim 1, wherein Z is an inert monovalent organic group, wherein n is an integer of 1 to 3 and m is an integer of 3 to n. [Chemical formula 1] The expandable resin particle according to claim 2, which is: 4. The foamable resin particles according to claim 1, wherein the volatile volatile foaming agent is propane, butane or pentane. 5. Styrene or a copolymerizable monomer mixture containing styrene as a main component, and tricyclo [5,2,1,0 ^2,6 ] deca-8-yl methacrylate and / or tricyclo [5 acrylate] [2,1,1,0 ^2,6 ] duka-8-yl is polymerized, and when the conversion is 40 to 90%, a polymerizable functional group-containing silane compound is added to the reaction system to complete the polymerization reaction. The method for producing expandable resin particles according to claim 1, 2, 3, or 4, which is obtained. 6. The method according to claim 1, wherein an easily volatile foaming agent is impregnated during or after the suspension polymerization.
5. The method for producing expandable resin particles according to 2, 3, or 4.