JPH0458828B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a P-methylstyrene resin foam. [Prior art] In recent years, foams based on polystyrene have been widely used as tableware containers, cushioning materials, heat insulating materials, etc. Among polystyrene foams, thick foams (approximately 5 mm thick) have been used in recent years. The above) have excellent insulation properties, so they are used in various types of insulation, such as roof base materials used under galvanized iron roofs and insulation and waterproofing materials for rooftops (for example, Utility Model No. 1150, 1983), which are used with a waterproof layer of asphalt on the surface. It is used as a material. [Problems to be solved by the invention] However, polystyrene foam has poor heat resistance, and when used as a roof base material, the roof base material deforms in the summer (under a tin roof in the summer, 80%
High temperatures of ℃ or higher may occur. ) Also, when used as a rooftop insulation and waterproofing material, the foam deforms when asphalt is applied (the temperature when asphalt is applied is over 80℃), and cannot withstand use at high temperatures of around 80℃ or higher. There was a problem. [Means for Solving the Problems] As a result of intensive research in order to solve the above problems, the present inventors found that the density of P-methylstyrene resin having a specific melt flow rate and Vikatsu softening point is used as a base resin. We have completed the present invention by discovering that a foam having a weight of 0.015 to 0.1 g/cm ³ and a thickness of 5 mm or more has excellent flexibility, heat resistance, and heat insulation, is lightweight, and has excellent mechanical strength. The present invention is a foam having a density of 0.015 to 0.1 g/cm ³ and a thickness of 5 mm or more, and the base resin of the foam is
Melt flow rate of 0.1~20g/10min and 110~
The gist of the present invention is a P-methylstyrene resin foam characterized by being a P-methylstyrene resin having a Vikato softening point of 120°C. P- used as base resin in the present invention
The methylstyrene resin used has a melt flow rate (hereinafter abbreviated as MFR) of 0.1 to 20 g/10 min, preferably 0.5 to 10 g/10 min, and a Vicat softening point of 110 to 120°C. MFR is 0.1
If P-methylstyrene resin is used at less than 10 g/10 min, only a stiff foam will be obtained and the MFR will be low.
If more than 20 g/10 minutes of resin is used, the heat resistance of the foam will decrease. Also, the softening point of Vikatsu is 110℃
If a P-methylstyrene resin with a temperature of less than 120° C. is used, the result is a foam with poor heat resistance, whereas if a resin with a temperature of more than 120° C. is used, the result is a hard and inflexible foam, which is not preferable. The above-mentioned P-methylstyrene resin used in the present invention is usually poly-P-methylstyrene, but it does not need to be a homopolymer of P-methylstyrene, and may contain a small proportion of m-methylstyrene. It can be something. Furthermore, other resins such as polystyrene, styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer, etc. A mixture of combinations and the like may be used. In the foam of the present invention, it is necessary to use a P-methylstyrene resin having the above-mentioned MFR and Vikatsu softening point as the base resin, and in order to ensure light weight, excellent heat insulation properties, and mechanical strength, 0.015 to 0.1
It is necessary to have a density of g/cm ³ , particularly preferably 0.02 to 0.05 g/cm ³ and a thickness of 5 mm or more, particularly preferably 10 to 100 mm. The foam of the present invention may further contain a flame retardant if necessary, and examples of the flame retardant include pentabromochlorocyclohexane, decabromodiphenyl oxide, antimony oxide, hexabromocyclohexane, tetrabromodichlorocyclohexane, and hexabromocyclohexane. Bromocyclododecane, pentabromoethylbenzene, 2, 4,
6-tribromophenyl-2-methyl-2,3-
Dibromopropyl ether and the like are used. The amount of flame retardant contained in the foam varies depending on the type of flame retardant, but is usually 0.1 to 5 parts by weight.
Approximately half the amount of flame retardant added in the case of polystyrene foam is sufficient. The blowing agent used in the production of the foam of the present invention is arbitrarily selected from the blowing agents used for ordinary foaming, such as propane, butane, n
- Aliphatic hydrocarbons such as pentane and isopentane, halogenated hydrocarbons such as dichlorodifluoromethane, tetrafluoroethane, trichlorofluoromethane, methyl chloride and ethyl chloride, and ethers such as methyl ether and ethyl ether. It will be done. Among these, mixtures of dichlorodifluoromethane and methane chloride and/or ethyl chloride, mixtures of dichlorodifluoromethane and butane, and mixtures of dichlorodifluoromethane and methyl chloride and/or ethyl chloride are preferred for molding. . [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Examples 1 to 3, Comparative Examples 1 to 5 MFR shown in Table 1 as a base resin, poly-P-methylstyrene having a Vicatto softening point, and methyl chloride and dichlorodifluoromethane for 100 parts by weight of the resin. and a blowing agent in the amount shown in Table 1, which is a mixture of 1:1 weight ratio, were uniformly melted and kneaded in an extruder, and then extruded through a die orifice with a gap of 6 mm (Comparative Example 5 was extruded through a circular die). ) was shaped into a plate using a guider having the height shown in Table 1 to obtain a foam having the density and thickness shown in Table 1. Table 1 shows the results of measuring the physical properties of this foam. Table 1 also shows the physical properties of a commercially available polystyrene foam as a reference example.

〔Effect of the invention〕

The foam of the present invention has a base resin of 0.1 to 20%
By using P-methylstyrene resin, which has an FFR of g/10 minutes and a Vikatsu softening point of 110 to 120°C, it has far superior heat resistance compared to foams based on polystyrene. has. Moreover, the foam of the present invention has a density of 0.015 to 0.1 g/cm ³ and a thickness of 5
mm or more, it is lightweight, has excellent heat insulation properties, mechanical strength, and heat resistance, and also has no risk of deformation like conventional polystyrene foam even when used as a base material for roofs, etc. This makes it an excellent heat insulating material for use at high temperatures. In addition, the foam of the present invention has sufficient flame retardancy even with the addition of about half the amount of flame retardant compared to conventional polystyrene foam, making it possible to provide a flame retardant foam at a low cost. It has the following effects.

Claims (1)

[Claims] 1 A foam with a density of 0.015 to 0.1 g/cm ³ and a thickness of 5 mm or more, and the base resin of the foam is 0.1 to 20
A P-methylstyrene resin foam, characterized in that it is a P-methylstyrene resin having a melt flow rate of g/10 minutes and a Vikato softening point of 110 to 120°C.