JPS60152531A - Production of radiation-crosslinkable flame-retarding transparent resin composition - Google Patents

Abstract

PURPOSE:To produce the titled resin composition which can give a crosslinked molding excellent in flexibility, transparency and flame retardancy, by mixing a mixture of an ethylene/acrylic acid copolymer and a polyfunctional monomer with a polyvinylidene fluoride resin. CONSTITUTION:20-80pts.wt. mixture of an ethylene/acrylic acid copolymer and a polyfunctional monomer is mixed with 80-20pts.wt. polyvinylidene fluoride. In the above mixture, the polyfunctional monomer is added for the purpose of improving the crosslinking efficiency of a molding. Because the polyfunctional monomer can not be uniformly dispersed in polyvinylidene fluoride resin, it is uniformly mixed by milling with the ethylene/acrylic acid copolymer, and the resulting mixture is uniformly mixed with the polyvinylidene fluoride resin in a mixer such as a tumbler. Although the amount of the polyfunctional monomer added depends on the aimed degree of crosslinking, it is generally 0.5-15wt% based on the total weight of the ethylene/acrylic acid copolymer and the polyvinylidene fluoride resin.

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 they do not ooze out the plasticizer added to give them flexibility. In many cases, the plasticizer contaminates the surface of the equipment or migrates to the insulated wire that the tube adheres to, so a non-plastic heat shrinkable tube that does not use a plasticizer has been desired.

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 retardant, transparency is impaired. Furthermore, although polyvinylidene butylene 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 an object of the present invention is to provide a method for producing a flame-retardant transparent resin composition that can realize a crosslinked molded product having excellent flexibility, transparency, and flame retardancy.

[Summary of the Invention] The production method of the present invention is characterized in that 80 to 20 parts by weight of a polyvinylidene butylene resin is mixed with 20 to 80 parts by weight of a mixture of an ethylene-acrylic acid copolymer and a polyfunctional monomer. It is something.

In the present invention, the mixing ratio of the mixture of the ethylene-acrylic acid copolymer and the polyfunctional monomer and the polyvinylidene butylene resin is limited because the mixture of the ethylene-acrylic acid copolymer and the polyfunctional monomer is 20 parts by weight or less. If it is, sufficient flexibility cannot be obtained, and 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 butylene resin, the polyfunctional monomers are kneaded into the ethylene-acrylic acid copolymer and mixed uniformly, and this is mixed together with polyvinylidene butylene resin in a tumbler, etc. Mix it evenly with a mixer. - The amount of the polyfunctional monomer added is not particularly limited as it is determined by the desired degree of crosslinking, but is generally 0.5 to 15% based on the total amount of the ethylene-acrylic acid copolymer and polyvinylidene butylene resin. Weight % is appropriate.

Examples of polyfunctional monomers include acrylates (diethylene glycol diacrylate, etc.), dimethacrylates (
diethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, etc.), triacrylates (trimethylolethane triacrylate, trimethylolpropane triacrylate, etc.), trimethacrylates (trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate) etc)
, triallyl cyanurate, triallyl isocyanurate, diallyl maleate, and the like.

The thus obtained mixture containing the ethylene-acrylic acid copolymer, polyfunctional monomer, and polyvinylidene fluoride is molded into a predetermined shape using an extruder, and then cross-linked by irradiation with ionizing radiation such as an electron beam. You can get a body. ' The resin M1 composition obtained according to the present invention can be applied to the production of various molded articles, but is particularly suitable for the production of heat-shrinkable tubes.

Heat-shrinkable tubes are manufactured by expanding the tube above its softening point or melting point and cooling it, but the tube cannot be expanded above its softening point or melting point because the resin used melts. .

Therefore, crosslinking is achieved to prevent the tube from melting. This crosslinking method includes chemical crosslinking, radiation crosslinking, etc., but chemical crosslinking does not include peroxides that can withstand the molding temperature of polyvinylidene fluoride resin.

Therefore, by using the resin composition obtained by the present invention that can be crosslinked by radiation, it becomes possible to easily produce a heat-shrinkable tube with excellent flexibility, transparency, and flame retardancy.

[Examples of the Invention] Resin compositions containing various components as shown in Table 1 were prepared. In this case, the ethylene-acrylic acid copolymer and the polyfunctional monomer (trimethylolpropane trimethacrylate, 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.

Evaluation results for sheets of composition on each side (as shown in the lower column of Table 1).

The evaluation was based on the following.

Combustion test: 5 Mradj] i! on a 2 mm thick sheet using a 1.5 MeV electron beam accelerator. After shooting, ASTMD63
Tested based on 5.

Transparency: After irradiating a sheet with a thickness of 0.5 nm with 5 Mrad using a 1.5 MeV electron beam accelerator, the transparency was determined visually.

Flexibility (scant modulus): A sheet with a thickness of 0.5 mrn was irradiated with 5 Mrad using a 1.5 MeV electron beam accelerator, and then tested based on UL224.

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

Table 1 (Amounts are in parts by weight) [Effects of the invention] As is clear from the above explanation, by using the resin composition obtained by the present invention, excellent flexibility, transparency, and flame retardance can be achieved. It becomes possible to obtain a molded product.

Claims (1)

[Claims] (1) A flame-retardant transparent material for crosslinking, characterized by mixing 80 to 20 parts by weight of a polyvinylidene butylene resin to 20 to 80 parts by weight of a mixture of an ethylene-acrylic acid copolymer and a polyfunctional monomer. Method for producing acid products by resin.