JPS6338061B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a foamable resin composition having good heat resistance. Conventionally, the well-known styrene resin foam has excellent heat insulation properties and has been used as covers for water and hot water pipes and other insulation materials. However, styrene resin foam has poor heat resistance, so it is It could not be used in applications that require heat resistance higher than the softening temperature of styrene resins, such as heat insulation for water piping. Therefore, in order to take advantage of the foam moldability of polystyrene resin and obtain a heat-resistant foam,
For example, it is possible to use a blend with a heat-resistant polymer such as high-density polyethylene or crystalline polypropylene as the base resin, but in this case, it is difficult to mix with styrenic resin and the retention of volatile blowing agents is poor. There are many problems such as poor moldability or failure to obtain a good quality foam due to unfavorable conditions. In addition to these resins, styrene and
An example of improving heat resistance using a maleic anhydride copolymer has been introduced (Japanese Unexamined Patent Publication No. 47-39186), but the production of this copolymer particle requires the unique reactivity of maleic anhydride. Therefore, it is pointed out in Japanese Patent Publication No. 47-49831 that a very complicated suspension polymerization step is required and a large amount of maleic anhydride is required, which is not economical. In addition, a foamable resin composition using a resin containing methyl methacrylate as a main component and α-methylstyrene as a secondary component has been proposed, but in this case, because the reactivity of α-methylstyrene is low, the third component is It is necessary to synthesize the suspension polymerization using a vinyl compound in combination at a high temperature of 95 to 130°C for about 20 hours (Japanese Patent Publication No. 182334/1983), which is economical because the polymerization temperature is high and takes a long time. Not. The present invention solves these problems and provides a foamable resin composition using a novel polymer. That is, the present invention provides a foamable resin composition comprising a polymer and a blowing agent, wherein the polymer is tricyclo[5.2.1.0 ^2,6 ]dec-8 methacrylate.
-yl and/or tricyclo[5.2.1.0 ^2,6 ]dec-8-yl acrylate as a constituent component.
It relates to a foamable resin composition containing up to 100% by weight. The polymer in the present invention is tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate (hereinafter referred to as monomer A) or tricyclo[5.2.1.0 ^2,6 ]dec-8-yl acrylate (hereinafter referred to as monomer A). Monomer B
), copolymers thereof, monomer A and/or monomer B, and at least one polymer selected from other polymerizable monomers, in which monomer A and/or At least 5% by weight of monomer B as a constituent
included. Monomer A and/or Monomer B
If it is less than 5% by weight as a constituent component in the polymer, the heat resistance of the foam will decrease. Monomer A and/or monomer B are preferably contained in the polymer in an amount of 10 to 100% by weight, particularly preferably 30 to 100% by weight. Examples of polymerizable monomers that can be copolymerized with monomer A and monomer B include styrene monomers such as styrene, vinyltoluene, isopropylstyrene, α-methylstyrene, nuclear-substituted methylstyrene, chlorostyrene, and tertiary-butylstyrene. , alkyl acrylates such as butyl acrylate, ethyl acrylate, methyl acrylate, alkyl methacrylates such as butyl methacrylate, ethyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, acrylonitrile, vinyl acetate, Examples include α-methylethylene and diethyl maleate, and mixtures thereof may also be used. The types and amounts of these ingredients should be determined to suit the final purpose. As other polymerizable monomers, monomers having two or more polymerizable double bonds such as divinylbenzene may be used, but in this case, 0 to 5% by weight based on the total amount of monomers. % or less. When the amount of such monomers increases, foaming properties tend to deteriorate. The polymer of the present invention can be obtained by any method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. Examples of the polymerization initiator used in the polymerization include monofunctional organic peroxides such as benzoyl peroxide, lauroyl peroxide, tertiary butyl perbenzoate, and tertiary butyl perpivalate, and 1,1-di-t- butylperoxy 3,3,5-trimethylcyclohexane,
Organic peroxides such as difunctional organic peroxides such as di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxytrimethyladipate, di-t-butylperoxyisophthalate, azobisisobutyl Azo compounds such as lonitrile and azobisdimethylvaleronitrile are used. The polymerization initiator may be added before adding the monomer into the polymerization container, after adding the monomer, or added together with the monomer. The polymerization initiator is preferably used in an amount of 0.01 to 10% by weight based on the total amount of monomers. The polymerization temperature is appropriately selected between 0 and 200°C. During polymerization, monomer A, monomer B and other polymerizable monomers may be polymerized. These polymers may be present in any manner such as dissolving them in monomers or impregnating them with monomers. Other polymers include polyphenylene ether, polybutylene terephthalate, and the like. Suspending agents used during suspension polymerization include:
Suspending agents that have been widely used in the past can be used, including water-soluble polymers such as polyvinyl alcohol, methylcellulose, and polyacrylamide, and sparingly soluble inorganic substances such as calcium phosphate and magnesium pyrophosphate. be. The water-soluble polymer is 0.03 to 1% of the total amount of monomers.
It is preferable to add the slightly soluble inorganic substance in an amount of 0.05 to 0.5 weight %. Further, as a suspending agent, an anionic surfactant such as sodium dodecylbenzenesulfonate can be added, and this is preferably used in combination when a sparingly soluble inorganic substance is used as a suspending agent. The amount used is preferably 0.001 to 0.02% by weight based on the total amount of monomers. In addition, during suspension polymerization, in order to adjust the particle size of the obtained polymer, sodium sulfate,
Electrolytes such as common salt, acidic sodium sulfite, etc. can be added to the aqueous medium. The amount of electrolyte used is preferably 0.0005 to 3% by weight based on the total amount of monomers. Further, a polymer of at least one monomer among the above monomer A, monomer B and other polymerizable monomers or another polymer is dispersed in advance, and monomer A and monomer in which a polymerization initiator is dissolved are dispersed. At least one monomer among B and other polymerizable monomers may be added continuously or intermittently for polymerization. In this case, the content of monomer A and/or monomer B is adjusted to be 5% by weight or more as a constituent component of the obtained polymer. When solution polymerization is employed, benzene, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, dichloroethylene, etc. can be used as the solvent. The polymer in the present invention may be a mixture of two or more polymers obtained from at least one of monomer A, monomer B, and other polymerizable monomers. Alternatively, a mixture of such a polymer and polyphenylene ether, polybutylene terephthalate, etc. may be used. The more the polymer in the present invention contains monomer A and/or monomer B as its constituent components, the more the heat resistance of the foam improves, and the foam becomes less foamable. In order to obtain a foam with higher foaming capacity, as a constituent component of the polymer in the present invention,
It is particularly preferable to increase the proportion of styrenic monomer. As the blowing agent in the present invention, an easily volatile organic compound that is liquid or gaseous at room temperature and pressure and does not dissolve the above polymer can be used. Examples of such substances include aliphatic hydrocarbons such as propane, butane, pentane, hexane, and petroleum ether, cyclic hydrocarbons such as cyclohexane, and halogenated aliphatic hydrocarbons such as methylene chloride, trichlorotrifluoroethane, and dichlorodifluoroethane. can be mentioned. The amount of these blowing agents used is preferably in the range of 1 to 20 parts by weight per 100 parts by weight of the polymer, depending on the content of monomer A and monomer B in the polymer and the desired expansion ratio. can be selected. Particularly preferably, it is used in an amount of 2 to 12 parts by weight per 100 parts by weight of the polymer. A plasticizer can be present during impregnation of the polymer with the blowing agent. As the plasticizer, an organic solvent capable of dissolving or swelling the polymer can be used, and one whose boiling point is preferably at least about 10°C lower than the softening point of the polymer and at most 150°C. Plasticizers include aromatic hydrocarbons such as ethylbenzene, toluene, styrene, benzene, and xylene;
1.2-dichloropropane, trichlorethylene,
Examples include halogenated hydrocarbons such as perchlorethylene. The plasticizer is preferably used in an amount of 0 to 5% by weight based on the polymer, and when used, it is preferably 0.5% by weight or more based on the polymer. In addition, as a blowing agent, N ₂ gas,
Pyrolytic chemical blowing agents that generate gases such as CO ₂ gas may also be used. These include azodicarbonamide, azobisisobutyronitrile, diazoaminobenzene, N,N'-dinitrolipentamethylenetetramine, benzenesulfonylhydrazide, trihydrazinotriazine, and the like. Such blowing agents are 0.5~
Preferably, it is contained in an amount of 5% by weight. In order to impregnate a readily volatile organic compound into a polymer, when suspension polymerization is adopted as the polymer production method, the easily volatile organic compound is added to the polymerization system (preferably by press injection) in the latter half of the polymerization. This can be done by doing. Here, the latter half of polymerization means that the polymerization conversion rate is 50% by weight or more, preferably 70% by weight or more. Another method is to suspend spherical or pellet-like particles of the polymer of the present invention in an aqueous medium and add a readily volatile organic compound thereto. Impregnation in suspension is preferably carried out at 90-130°C. Alternatively, the polymer of the present invention and the easily volatile organic compound may be melt-mixed. In this case, extruders are mainly used. When a thermally decomposable blowing agent is used, it is melt-mixed with the polymer of the present invention at a temperature below the decomposition temperature of the blowing agent. Also at this time, an extruder is mainly used. Note that the foamable resin composition according to the present invention may contain known additives such as pigments, flame retardants, antioxidants, and antistatic agents. Foaming of the foamable resin composition according to the present invention involves heating,
This is done using methods such as depressurization. As the method, the foaming and molding methods of styrenic resin, which are widely used industrially, can be applied as they are. For example, if the resin is in the form of particles, it can be pre-foamed with steam and then further steam-foamed in a molding machine to obtain a molded product. Moreover, a foam can also be obtained using an extrusion foaming machine. The expansion ratio of the foamable resin composition according to the present invention is
The magnification can be arbitrarily selected from low magnification to high magnification. Applications of the foam obtained from the foamable resin composition of the present invention include solar-related insulation materials, hot water tank insulation materials, metal tile underlay materials, insulation materials for school lunch containers, insulation materials for vehicles and ships, and hot water insulation materials. Possible materials include pipe heat insulation materials, air conditioner windshields, sizing boards, automobile-related structural materials, and metal simultaneous molding panels. Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, hereinafter, "parts" and "%" are based on weight. In addition, physical properties were measured according to the following method. <Glass transition temperature> Dissolve 1 g of the polymer in 10 ml of chloroform, dry under reduced pressure and heat, and use a film with a thickness of 0.3 mm as a sample.
Measurements were made using a TM-1500 thermomechanical testing machine manufactured by Shinku Riko Co., Ltd. <Production of pre-foamed product> Pre-foamed particles are obtained by heating expandable polymer particles having a particle diameter of 0.5 to 1.2 mm with steam at 115°C for 3 minutes. After aging this at room temperature for 24 hours, the pre-foamed particles were placed in a graduated cylinder No. 1, and the apparent foam density (g/) was determined. <Molding of foam> The above pre-foamed particles were filled into a mold with dimensions of 300 mm long, 400 mm wide, and 10 mm thick, and heated to 0.6 Kg/cm ² G (113°C), 0.8 Kg in a table autoclave. /
cm ²・G (116℃), 1.0Kg/cm ²・G (120℃), 125Kg/
cm ²・G (123℃), 1.50Kg/cm ²・G (127℃), 1.75
After heating with steam of Kg/cm ² ·G (130° C.) and 2.0 Kg/cm ² (133° C.) for 60 seconds and 120 seconds, the foam was cooled to produce a foam. <Evaluation of Heat Resistance> When molding in a table-type autoclave, the pressure and number of seconds at which shrinkage starts due to steam were measured. <Water method shrinkability> A molded product with good internal fusion and external finish of the foam was cut into test pieces of 100 x 100 x 10 mm, dried at 50°C for one day and night, and then tested at 100°C, 105°C, 110°C, and 115°C. , left unloaded in a constant temperature dryer set at a temperature of 120°C.
Determine the dimensional changes after 10, 40, 100, and 200 hours,
The critical temperature at which no dimensional change occurs was determined. Example 1 Tricyclo methacrylate [5.2.1.0 ^2,6 ] Deca-8
-yl (monomer A) 350g and styrene 650g
1.71 g of benzoyl peroxide, 0.67 g of 1,1-di-t-butylperoxy 3,3,5-trimethylcyclohexane and 0.5 g of t-butyl perbenzoate are added to a mixed solution of vinyl compounds consisting of
After dissolving the solution, put the solution into 3 autoclaves in which 1200 g of water, 2 g of tricalcium phosphate, 6 g of 0.5% sodium dodecylbenzenesulfonate solution, and 0.75 g of sodium sulfate were dispersed or dissolved.
The autoclave was charged under stirring at 270 rpm, and the atmosphere inside the autoclave was replaced with nitrogen gas. Next, when the temperature was raised to 90°C and stirred at the same temperature for 5 hours, the butane
After that, the mixture was heated to 120° C., heated and stirred at the same temperature for 4 hours, and then cooled to produce expandable polymer particles. After cooling, the expandable polymer particles were taken out, washed with hydrochloric acid, and air-dried. The average particle diameter of the obtained particles was 0.89 mm, and the total amount of volatile components
It was 9.2%. These expandable polymer particles were pre-foamed to obtain pre-foamed particles with an apparent density of 25 g/.
A foamed molded article was obtained using the pre-expanded particles. Table 2 shows the composition of the vinyl compound, the glass transition temperature of the polymer, and the apparent density, heat resistance, and dimensional shrinkage of the foam molded product. Note that the dimensional shrinkage was determined from the dimensional changes at each temperature and each time. The results are shown in Table 1.

[Table] From the dimensional change data in Table 1, the limit temperature for the dimensional shrinkage of this foam molded product is 110
℃. Examples 2 to 4 and Comparative Example 1 Expandable polymer particles were obtained in the same manner as in Example 1 except that the amounts of monomer A and styrene were as shown in Table 2. These expandable polymer particles were pre-foamed and foam-molded in the same manner as in Example 1, and the apparent density, heat resistance, and dimensional shrinkage of the obtained product were measured. The results are shown in Table 2.

[Table] Examples 5 to 8 Expandable polymer particles were produced and tested in the same manner as in Example 1, except that the composition of the vinyl compound in Example 1 was changed as shown in Table 3. Table 3 shows the composition of the vinyl compound, the glass transition temperature of the polymer, and the apparent density, heat resistance, and dimensional shrinkage of the foam molded product.

【table】

【table】

[Table] Example 9 1500g of ion-exchanged water, 4.5g of polyvinyl alcohol (W-24 manufactured by Denki Kagaku Kogyo Co., Ltd.) and polystyrene particles (0.6mm
~0.8mm diameter) was charged and the temperature in the system was raised to 80℃ while stirring. Tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate (monomer A)
125 g of a solution of 500 g and 15 g of toluene was added dropwise three times at 20 minute intervals. Next, add 1,1 to the remaining monomers.
- Dissolve 2.67 g of di-t-butylperoxy 3,3,5-trimethylcyclohexane and 0.5 g of t-butyl perbenzoate, and after the third addition of the solution.
The same addition was made 30 minutes later. After continuing the reaction for an additional 3 hours, 80 g of butane was added and the temperature was raised to 115°C.
Thereafter, stirring was continued for 3 hours while maintaining this temperature.
Thereafter, the mixture was cooled to 30° C., excess gas in the system was discharged, and the mixture was dried separately to obtain particles of a foamable polymer composition. These particles were molded according to Example 1. The obtained foamed molded product was used to measure the apparent temperature, heat resistance, and dimensional stability. The results are shown in Table 4. Example 10 500 g of tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate in an autoclave equipped with a rotary stirrer
and 250 g of styrene were added, and while stirring, 250 g of polyphenylene ether (PPO manufactured by Engineering Plastics) was added, and the mixture was completely dissolved in 2 hours while purging with nitrogen gas. After complete dissolution, dissolve 2.3 g of benzoyl peroxide and 1.5 g of t-butyl perbenzoate, then stop stirring, add 2000 g of ion-exchanged water, restart stirring, and dissolve 5 g of tricalcium phosphate and 0.5% sodium dodecylbenzenesulfonate solution. 6g and 0.75g of sodium sulfate were added to start suspension polymerization. The subsequent operations were performed in the same manner as in Example 1 to obtain expandable polymer particles. These particles were molded according to Example 1. The obtained foamed molded product was used to measure its apparent density, heat resistance, and dimensional stability. The results are shown in Table 4. Example 11 1800g of xylol (150 g
parts by weight) and while stirring through an inert gas.
Heat to 100℃ and add 600g (50 parts by weight) of tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate.
and tricycloacrylate [5.2.1.0 ^2,6 ] deca-8-
A mixture of 600 g (50 parts by weight) of azobisisobutyronitrile and 15 g (1.25 parts by weight) of azobisisobutyronitrile was added dropwise over 2 hours. After dropping, the reaction temperature was raised to 120°C, and
After the reaction was allowed to proceed for a certain period of time, it was determined as the end point. Then, the xylene used as a solvent was separated by heating and distillation. After pelletizing the polymer thus produced using a pellet molding machine, 1500 g of ion-exchanged water, 3.0 g of tricalcium phosphate and 10 g of a 0.5% solution of sodium dodecylbenzenesulfonate were added to an autoclave equipped with a rotary stirrer (No. 4). 4.5g of calcium carbonate and 1000g of pellets were charged, and the temperature inside the system was raised to 80℃ while stirring. After heating up, ethylbenzene
15g was added, and 80g of butane gas was also pressurized. Thirty minutes after the butane gas was pressurized, the temperature began to rise again, and after 2 hours, the temperature was raised to 115°C, and stirring was continued for 3 hours while maintaining this temperature. Thereafter, the mixture was cooled to 30° C., excess gas in the system was discharged, and the mixture was dried separately to obtain particles of a foamable polymer composition. These particles were molded according to Example 1. Using the obtained foam molded product, the apparent density,
Heat resistance and dimensional stability were measured. The results are shown in Table 4. Comparative Example 2 In Example 10, monomer A was not used, and polyphenylene ether was added to 750 g of styrene monomer.
A foamable molded product was obtained in the same manner as in Example 10, except that 250 g was dissolved, and its apparent density, heat resistance, and dimensional stability were measured. The results are shown in Table 4.

[Table] As is clear from the above, the foam molded article obtained from the foamable resin according to the present invention has excellent heat resistance.

Claims (1)

[Scope of Claims] 1. A foamable resin composition comprising a polymer and a blowing agent, wherein the polymer is tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate and/or tricyclo[5.2.1.0 2,6]dec-8-yl acrylate. 5.2.1.0 ^2,6 ] A foamable resin composition containing 5 to 100% by weight of dec-8-yl as a constituent component. 2 The polymer contains tricyclo[5.2.1.0 ^2,6 ]dec-8-yl methacrylate and/or
or tricyclo[5.2.1.0 ^2,6 ]decacrylate
5 to 95% by weight of 8-yl, 95% of styrenic monomer
The foamable resin composition according to claim 1, which contains 100% by weight of 5% by weight and 90% to 0% by weight of other components.