JPS59217750A - Production of flame-retardant cross-linked moldings - Google Patents

Abstract

PURPOSE:A compound of a silyl-modified polyolefin and a flame-retardant is extruded and the product is brought into contact with a siloxane condensation catalyst and water, thus permitting sufficient kneading and giving moldings with increased crosslinking degree and good appearance. CONSTITUTION:A polyolefin is allowed to react with a mixture of a silane and a radical initiator with heat and the resultant silyl-modified polyolefin is mixed with a flame-retardant. Then, the compound is subjected to extrusion molding and the products are brought into contact with a siloxane condensation catalyst and water. As the polyolefin, is used polyethylene or ethylene-vinyl acetate copolymer; as a silane, vinyltrimethoxysilane and as the condensation catalyst, dibutyltin dilaurate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a flame-retardant crosslinked molded article.

The conventionally proposed method for producing flame-retardant crosslinked molded products using the silane craft water crosslinking method involves extrusion molding of high-concentration flame retardant master nototsuchi containing silyl-modified polyolefin pellets, a siloxane condensation catalyst, and a flame retardant. 1 to 2, a crosslinked molded article imparted with flame retardance is obtained by contacting with water.

However, according to this method, there is a problem that the base polymer of the master layer containing a high flame retardant concentration eventually becomes a non-crosslinked component 9, resulting in a decrease in the degree of crosslinking.

The present invention solves the problems of the prior art described above, and aims to provide a method for producing a flame-retardant crosslinked molded article that can increase the degree of crosslinking.

That is, the present invention involves extrusion molding a silyl-modified polyolefin obtained by heating a mixture of a polyolefin, a silane compound, and a radical generator, mixed with a flame retardant. It is characterized in that it is cross-linked by contacting with water and water.

In the present invention, polyolefins include polyethylene, ethylene-vinyl acetate copolymer, ethylene-copolymer with acrylic acid or its ester, ethylene-propylene (17'cUJ monomer) copolymer, ethylene-vinyl acetate copolymer,
Examples include butylene copolymers, halogenated polyolefins, and those obtained by graft polymerization of vinyl chloride monomers.

Examples of silane compounds include vinyltrimethoxysilane and vinyltriethoxy/ran; examples of radical generators include dicumyl ξ-oxide, isbenzoyl peroxide, and toca such as nochlorobenzoyl peroxide; and butyltin as a lanol condensation catalyst. Examples include dilaurate and dibutyltin diacetate.

Further, as the flame retardant, additive flame retardants such as halogen flame retardants, phosphorus flame retardants, and inorganic flame retardants are preferable, but are not limited thereto.

In the present invention, different types of polymers, antioxidants, stabilizers, flame retardant aids, fillers, colorants, weatherability imparting agents, heat exchangers or electrical conductivity agents, etc. may be added as necessary. There is no problem in adding it.

Examples of the present invention will be described below.

Density 0.93 g/ctrl, melting index tsg/l
To 100 parts by weight of pellets of ethylene-ethyl acrylate copolymer (DPDJ6182 manufactured by Nippon Unicar Co., Ltd.), 15 parts by weight of vinyltrimethquine, 15 parts by weight of dicumylno ξ-oxyro, ts, 3 ,5-di-tert-butyl-4hydroxy)hi1:''
After mixing 1 part by weight of Ro/Nnamate 0, the mixture was charged into a 100 m/m single-screw extruder and granulated while undergoing a heating reaction to produce a silyl-modified polyethylene casing. Magnesium hydroxide and stearic acid were added to 100 parts by weight of Beretsu 1-1 in the amounts shown in Table 1 for winter, kneaded with rolls, taken out in the form of a sheet, and pelletized using a pelletizer.

Next, this was fed to the barrel ξ- of a ]00 m/m single screw extruder, and the temperature of barrel zones 1 to 3 = 160 °C,
Diameter 30m under crosshead temperature = 170℃
An electric wire was obtained by extrusion coating the outer periphery of the cable core with an insulator having a thickness of 1.0 mm.

The wire was immersed in an emulsion of water and dibutyltin dilaurate (temperature = 80° C.) for 24 hours to crosslink the insulator.

The evaluation results of the insulator thus obtained are as shown in the lower column of the first coat, and it is clear that a sufficient degree of crosslinking can be achieved even when a large amount of flame retardant is filled.

The xylene-insoluble matter was extracted in xylene at 110° C. for 24 hours, thoroughly dried, and then measured. Moreover, the maximum smoke density was measured using NBS Smoke Char/Nono-.

Table 1 5- As mentioned above, in the present invention, since no siloxane condensation catalyst is present during extrusion molding, sufficient crosstalk is possible, the dispersibility of additives is improved, the extruded appearance is excellent, and a large amount of flame retardant is mixed. This makes it possible to obtain a molded article with excellent flame retardancy.

Note that the present invention is not limited to the manufacture of electric wires,
It can also be applied to manufacturing tubes, pipes, sheets, etc.

6- Procedural Amendment I, Indication of Case 1982 Patent Application No. 92950
No. 2 Title of the invention Method a for producing a flame retardant crosslinked molded product
Address of the person making the amendment: 2-1-2-4 Marunouchi, Chiyoda-ku, Tokyo; Agent address: 100 Address: Tokyo (2-1-2, Marunouchi, Daita-ku; Subject of amendment (1): Details of the invention in the specification explanation.

Contents of the amendment (1) "Ethylene" on page 4, line 5 of the specification is corrected to "olefin."

that's all 2-

Claims (1)

[Claims] ■ A flame retardant is mixed with a silyl-modified polyolefin obtained by subjecting a mixture of a polyolefin, a silane compound, and a radical generator to a thermal reaction, and a compound is extruded, and a siloxane condensation catalyst and moisture are added to the extruded product. A method for producing a flame-retardant crosslinked molded article, the method comprising contacting the flame-retardant crosslinked molded article.