JPS60137952A - Production of flame-retardant transparent resin composition for radiation crosslinking - Google Patents

Abstract

PURPOSE:To provide the titled composition giving a crosslinked article having excellent flexibility, transparency and flame-retardancy, by compounding a polyurethane with a polyfunctional monomer and a polyvinylidene fluoride resin at specific ratios. CONSTITUTION:(A) A polyurethane is mixed with (B) a polyfunctional monomer (e.g. acrylate, dimethacrylate, etc.). 20-80pts.wt. of the above mixture is compounded with (C) 80-20pts.wt. of a polyvinylidene fluoride resin, and the obtained composition is formed and crosslinked by ionizing radiation such as electron ray. The amount of the component B is preferably 0.5-15wt% based on the sum of A and C.

Description

Detailed Description of the Invention [Background and Objectives of the Invention] The present invention relates to a method for producing a flame-retardant transparent resin composition capable of obtaining a crosslinked molded product having excellent flexibility, transparency, and flame retardancy. It is something.

For example, when using heat-shrinkable tubes to connect internal wiring in equipment or to process terminals, it is recommended to use highly transparent tubes so that the condition of the connections can be visually checked, and highly flexible tubes for ease of handling. It is being Furthermore, it is required to be flame retardant in case of fire.

Therefore, polyvinyl chloride resin compositions that have excellent transparency and flame retardancy have been used for applications in this field, but these have an IF flexibility agent added to give them flexibility. Flexible agents often seep into the equipment and contaminate the surface of the equipment, or migrate to the insulated wires that the tube is attached to.
There has been a desire for a non-IIJ plastic type heat shrinkable tube that does not use an IF flexure agent.

However, polyethylene, which is a non-plastic type resin, or a copolymer mainly composed of ethylene has poor flame retardancy, and when a flame retardant is added to make it flame-resistant, transparency is impaired. Furthermore, although polyvinyritine fluoride resin has excellent flame retardancy and transparency, it is hard and therefore not suitable for use in moving parts.

The present invention is based on the above, and proposes a method for producing a flame-retardant transparent resin composition that can realize a crosslinked molded product having excellent flexibility, transparency, and flame retardancy. be.

[Summary of the invention]

The manufacturing method of the present invention is characterized in that 80 to 20 parts by weight of a polyvinylidene butrate resin and 1 part are mixed with 20 to 80 parts by weight of a mixture of polyurethane and a polyfunctional monomer.

In the present invention, the mixing ratio of the mixture of polyurethane and polyfunctional monomer and polyfluorinylidene resin is limited because sufficient -il flexibility can be obtained when the mixture of polyurethane and polyfunctional monomer is 20 parts by weight or less. Moreover, if it exceeds 80 parts by weight, it becomes easily flammable.

In the present invention, a polyfunctional monomer is added to improve the crosslinking efficiency of the molded article. Since polyfunctional monomers do not disperse uniformly in polyvinylidene fluoride resin, the polyfunctional monomers are kneaded into polyurethane and mixed uniformly, and then mixed uniformly with polyvinylidene fluoride resin in a mixer such as a tumbler. I will do it.

The amount of the polyfunctional monomer added is determined by the desired degree of crosslinking and is not particularly limited, but is generally 0.5 to 0.5 to the total amount of polyurethane and polyvinylidene fluoride resin.
15% by weight is suitable.

Examples of polyfunctional monomers include acrylates (diethylene glycol diacrylate, etc.), dimethacrylates (
Diethylene glycol dimethacrylate, dipropylene gelicol dimethacrylate-1;>, triacrylates (trimethylolethane triacrylate, trimethylolpropane triacrylate, etc.), trimethacrylate m() trimenaloethane trimethacrylate tri methylolpropane trimeta gamma acrylate, etc.),
Examples include triallyl cyanurate, triallyl in cyanurate, diallyl malate, and the like.

The thus obtained mixture containing polyurethane, polyfunctional monomer and polyvinylidene fluoride is molded into a predetermined shape using an extruder, and then crosslinked by irradiation with ionizing radiation such as an electron beam to obtain a crosslinked molded product. can.

The resin composition obtained by the present invention can be applied to the production of various molded objects, but is particularly suitable for the production of heat-shrinkable chicoop.

Heat-shrinkable tubes are manufactured by expanding the tube above its softening point or melting point and then cooling it. However, at temperatures below the softening point or melting point, the resin used melts, so the tube cannot be expanded. I can't.

Therefore, crosslinking is achieved to prevent the tube from melting. This crosslinking method includes chemical crosslinking, radiation crosslinking, etc. However, in chemical crosslinking, there is no peroxide that can withstand the molding temperature of polyvinylidene butylene resin. By using the resin composition, it becomes possible to easily produce a heat-shrinkable tube with excellent flexibility, transparency, and flame retardancy.

[Embodiments of the invention]

A resin composition containing various components as shown in Table 1 was prepared. In this case, the polyurethane and the polyfunctional monomer (trimethylolpronotrimethacrylate, triallyl isocyanurate) were mixed uniformly, and then mixed with the polyvinylidene butylene resin.

The resin composition thus obtained was press-molded into a sheet and irradiated with an electron beam accelerator.

The il'F 4 song results for each side composition sheet are i
It is as shown in the lower column of table f.

The evaluation was based on the following.

Combustion test: 1.5 MeV on a 2 + nm thick sheet. After 5 Mrad irradiation with IE particle accelerator, ASTMD
Tested based on 635.

Transparency: thickness Q, 1.5 N on a 5 mm sheet
After 5 Mrad irradiation with a cV electron beam accelerator, the judgment was made visually.

'T flexibility (scant modulus) thickness Q, 5 m
5 m sheet with a 1.5 M e V electron beam accelerator
After M r'ad irradiation, it was tested according to UL224.

The judgment was based on the UL224 flexible type judgment criteria.

[Effect of investigation]

As is clear from the above description, by using the resin composition obtained by the present invention, it is possible to obtain a molded article with excellent flexibility, transparency, and flammability.

Procedural amendments (side) 1. Indication of the incident 1979 Request for permission No. λyo2o7fu No. 2 Name of Geshuヅη方人a Representative of the person making the correction Water Ryo Tokugobu 9th Literary Person〒100 4, 腓'ko#'If:Inel Karikato 7 叡ψ' rEh Meat 2 Mariruju no J, SuJ,
shi 179 now 811 go

Claims (1)

[Claims] (1) Mixture of polyurethane and polyfunctional monomer 20-8
80 to 20 parts by weight of polyvinylidene resin
A method for producing a flame-retardant resin composition for irradiation crosslinking, the method comprising mixing parts by weight.