JPS60135448A - Preparation of flame-resistant transparent resin composition crosslinkable by irradiation - Google Patents

Abstract

PURPOSE:To obtain the titled polymer composition having excellent flexibility, transparency, and flame-resistance, suitable for the manufacture of heat-shrinkable tubing, by mixing a polyvinylidene fluoride with a mixture of a polyvinyl methyl ether and a polyfunctional monomer. CONSTITUTION:80-20pts.wt. polyvinylidene fluoride resin (A); and 20-80pts.wt. mixture (B) of polyvinyl methyl ether (a) and 0.5-15wt% based on a + A, polyfunctional monomer (b) (e.g. diethylene glycol diacrylate) are mixed uniformly in a mixer such as a tumbling mixer to obtain the titled resin composition. The composition is formed to a specified shape with an extruder, followed by irradiation with ionizing radiation such as electron beams, causing crosslinking thereof to obtain crosslinked moldings.

Description

Detailed Description of the Invention [Background and Objectives of the Invention] The present invention provides 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 related to.

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

Therefore, for applications in this field, transparency is superior to conventional methods.
A flame-retardant polyvinyl chloride plum fat composition is used, but this does not bleed through the plasticizer added to give it flexibility, contaminating the surface of the equipment, or causing damage to the adherends of tubes. Plasticizers often migrate to certain insulated wires, and a non-plastic type heat shrink tube that does not use plasticizers 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 aims 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 8 parts by weight of a mixture of polyvinyl methyl ether and a polyfunctional monomer. be.

In the present invention, the mixing ratio of the mixture of polyvinyl methyl ether and polyfunctional monomer and the polyvinylidene butylene resin is limited because if the mixture of polyvinyl methyl ether and polyfunctional monomer is 20 parts by weight or less, sufficient flexibility is achieved. is not 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 polyvinyl methyl ether and mixed uniformly, and this is uniformly mixed with polyvinylidene butylene resin in a mixer such as a tumbler. It will be mixed with.

The amount of the polyfunctional monomer added is not particularly limited as it is determined by the desired degree of crosslinking, but in general, 0.5 to 16% by weight is appropriate based on the total amount of polyvinyl methyl ether and polybutylated vinylidene plum fat. It is.

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

The thus obtained mixture containing polyvinyl ether, 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 tubes.

Heat-shrinkable tubes are manufactured by expanding the tube above its softening point or melting point and then cooling it, but the tube cannot be expanded above the 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 plumbum 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, polyvinyl ether and polyfunctional monomers (trimethylolbrohant trimethacrylate, triallyl isocyanurate) were mixed uniformly, and then mixed with polyvinylidene butylene resin.

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

The evaluation results for the separate sheets of each example are shown in the lower column of Table 1.

The evaluation was based on the following.

Combustion test: After irradiating a 2 mm thick sheet with 5 Mrad in a 1.5 MeV electron beam accelerator, A S 'I' MD
Tested based on 636.

Transparency was determined by visual inspection after irradiating 5 Mrad on a sheet 1 with a thickness of 0.5 mm using a 1-5 MeV electron beam accelerator.

Flexibility (scant modulus): A 0.5 mm thick sheet 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. This makes it possible to obtain a molded product.

Claims (1)

[Claims] (1) A flame-retardant plum fat composition for irradiation crosslinking, the main feature of which is mixing 80 to 20 parts by weight of a polyvinylidene butylene resin to 20 to 80 parts by weight of a mixture of polyvinyl methyl ether and a polyfunctional monomer. manufacturing method.