JPH0214371B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to crosslinkable polyolefin compositions. More details: polyolefin, xylene
α,α′-diyl-bis[3,5-di-(2-propenyl)-1,3,5-triazine-2,4,6
-(1H,3H,5H)-trione] and an organic peroxide, the present invention relates to a polyolefin composition with excellent crosslinking speed and crosslinking effect. Cross-linked polyolefin maintains the original excellent properties of polyolefin, such as electrical properties and mechanical strength, while improving heat resistance, chemical resistance, environmental stress cracking resistance, and elastic modulus, making it suitable for heat-resistant insulation for power supplies and cables. It is widely used in the fields of pipes, tubes, and films, as well as packing and gaskets. In general, known crosslinking methods for polyolefins include a crosslinking method using an organic peroxide, such as that found in polyethylene, and a crosslinking method using water after grafting a silane compound. Furthermore, as a crosslinking method for ethylene-propylene copolymer, chlorinated polyethylene, ethylene-vinyl acetate copolymer, etc., a polyfunctional compound having two or more unsaturated groups in one molecule is used in combination with an organic acid peroxide. There are also known methods. Polyolefins are inherently difficult to crosslink, and it is difficult to quickly obtain a crosslinked product with a high crosslink density using organic peroxides. In order to obtain a high crosslink density, a long reaction time is required, and if the reaction is attempted to proceed quickly, the result is a crosslinked product containing a non-uniform gel. In addition, molecular chain scission occurs, resulting in an increase in by-products. In the method of grafting a silane compound, the crosslinking rate is slow, and in order to increase the internal crosslinking density in particular, it is necessary to immerse the material in water for a long time or at a high water temperature for a long time. In addition, in the combination of organic peroxide and polyfunctional compound, acrylic ester, methacrylic ester, diallyl phthalate, triallyl isocyanurate, etc. are usually used as the polyfunctional compound, but these substances Since it is liquid at room temperature and has poor compatibility with polyolefin, it has poor dispersibility during kneading and is difficult to uniformly disperse. Further, after kneading, a phenomenon called so-called bleed or blooming occurs in which the polyfunctional compound oozes out onto the surface of the kneaded material over time. These things are extremely unfavorable in obtaining a uniform crosslinked product. The present inventors completed the present invention as a result of research to solve the above-mentioned drawbacks. That is, the gist of the present invention is that polyolefin, xylene-α,α'-diyl-bis[3,5-di-(2-propenyl)-1,3,5
-Triazine-2,4,6-(1H,3H,5H)-
Trion] and an organic peroxide. In the above xylene derivative, the xylene derivative is o-xylene-α,α′-diyl-bis[3,5-
di-(2-propenyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione], m
-xylene-α,α′-diyl-bis[3,5-di-(2-propenyl)-1,3,5-triazine-
2,4,6-(1H,3H,5H)-trione] and p-xylene-α,α′-diyl-bis[3,5-
di-(2-propenyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione] can be applied. Examples of the polyolefin of the present invention include the following polymers. That is, thermoplastic polymers generally called polyolefins can be used, ranging from crystalline to non-crystalline types. Also included are polyolefin derivatives obtained by chemically or physically treating polyolefin. Specific examples include high-pressure polyethylene, low-pressure polyethylene, medium-low-pressure polyethylene, isotactic polypropylene, syndiotactic polypropylene, atactic polypropylene, polybutene, 4-methylpentene-1, and other α-olefin polymers. Other examples include chlorinated polyethylene, chlorosulfonated polyethylene, halogenophosphorized polyethylene, and grafted modified polyethylene obtained by grafting maleic anhydride, fumaric acid, acrylic acid, methacrylic acid, etc. onto polyethylene. Also included are olefin copolymers described below. Namely, random copolymers of ethylene and α-olefin, block copolymers of ethylene and α-olefin, copolymers of ethylene or α-olefin and other vinyl monomers, ethylene or α-olefin and conjugated dienes. Examples include alternating copolymers with Specifically, ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-propylene stereoblock copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene- Examples include methyl methacrylate copolymer, propylene-butadiene alternating copolymer, ethylene-diallyl ester copolymer, and the like. As an organic peroxide, the 1-minute half-life temperature is approximately 160°C.
-240°C is particularly preferred, such as t-butyl peroxyisopropyl carbonate, di-t-butyl diperoxy phthalate,
t-butylperoxyacetate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxylaurate, t-butylperoxymale acid, t-butylperoxybenzoate, Examples include methyl ethyl ketone peroxide, dicumyl peroxide, cyclohexanone peroxide, cyclohexanone peroxide, and t-butyl dicumyl peroxide. Two or more of these organic peroxides may be used in combination. Also, the amount of these additions is per 100 parts by weight of polyolefin.
The amount is 0.001 to 0.02 mol, preferably 0.005 to 0.01 mol. Xylene-α,α′-diyl-bis[3,5-di-(2-propenyl)-1,3,5-triazine-
2,4,6-(1H,3H,5H)-trione] is added in an amount of 0.5 to 10 parts by weight, preferably 3 to 8 parts per 100 parts by weight of polyolefin. The composition of the present invention is produced by kneading at room temperature or under heating using a commonly used mixer such as a mixing roll, calendar roll, kneader, or extruder. There is no problem in using additives such as pigments, fillers, lubricants, process oils, heat stabilizers, antioxidants, and ultraviolet absorbers during kneading. The composition of the present invention can be rapidly crosslinked by heating to 150 to 180°C, and can provide a crosslinked polyolefin with a high crosslink density. Generally, when crosslinking polyolefins with organic peroxides, polyfunctional compounds such as trimethylolpropane trimethacrylate, triallyl isocyanurate, triallyl cyanurate, 1,2
It is known that polybutadiene and the like are used as crosslinking aids;
3,5-triazine-2,4,6-(1H,3H,
The fact that a polyolefin containing 5H)-trione has a specifically high crosslinking rate and a large crosslinking effect was revealed for the first time by the present inventors. Although it is not clear why the polyolefin composition of the present invention has a fast crosslinking rate and excellent crosslinking effect,
di-(2-propenyl)1,3,5-triazine-2,4,6-(1H,3H,5H)-trione] has better compatibility with polyolefins than conventional polyfunctional compounds. This is presumed to be because homogeneous kneading and crosslinking became possible. Next, the present invention will be explained using the present example. In the examples, "part" means part by weight, and "%" means weight %. Example 1 and Reference Example 1 Polyethylene (MI=2.0) was kneaded at 135°C for 5 minutes after adding organic peroxide using a Prabender plasticorder with the formulation shown in Table 1.
Thereafter, a sheet with a thickness of 2 mm was produced by pressure molding at 180°C. 0.1g of the obtained cross-linked polyethylene
ml Erlenmeyer flask, add 100 ml of toluene, attach a backflow condenser, boil for 8 hours on a hot plate, then take out the contents, air dry, vacuum dry at 50°C, and measure the toluene insoluble area as gel fraction. did. Table 2 shows the relationship between crosslinking time and gel fraction.

【table】

[Table] Example 2 and Reference Example 2 Ethylene-propylene-diene rubber (EPDM)
With the formulation shown in Table 3, the roll size is 20.3
Using a ×45.7cm roll mixer, rotation ratio: 1:
The mixture was kneaded at a temperature of 50±5° C. at a rotation speed of 1.8 rpm and 18 rpm. Table 4 shows the relationship between vulcanization time and physical properties when the material was then vulcanized at 150°C. Measurement of physical properties of vulcanized products is based on JIS
Compliant with K6301.

【table】

[Table] Example 3 and Reference Example 3 Chlorinated polyethylene was kneaded at 60±5°C using the same rolls as in Example 2 with the formulations shown in Table 5. Vulcanization time and JIS when vulcanized at 160℃
Table 6 shows the physical properties of the vulcanizate determined in accordance with K6301.

【table】

[Table] Example 4 and Reference Example 4 Regarding the ethylene-vinyl acetate copolymer, the seventh
A roll similar to Example 2 was used with the formulation shown in the table.
Table 8 shows the vulcanization time when kneaded at 30 to 40°C and vulcanized at 160°C, and the physical properties of the vulcanizate according to JIS K6301.

【table】

[Table] After time aging

Claims (1)

[Scope of Claims] 1 Polyolefin, xylene-α,α'-diyl-bis[3,5-di-(2-propenyl)-1,
3,5-triazine-2,4,6-(1H, 3H,
5H)-trione] and an organic peroxide. 2. In the polyolefin composition according to claim 1, xylene-α,α'-diyl-
Bis[3,5-di-(2-propenyl)-1,3,
5-triazine-2,4,6-(1H,3H,5H)
-trione] is o-xylene-α,α′-diyl-
Bis[3,5-di-(2-propenyl)-1,3,
5-triazine-2,4,6-(1H,3H,5H)
- Trion]. 3. In the polyolefin composition according to claim 1, xylene-α,α'-diyl-
Bis[3,5-di-(2-propenyl)-1,3,
5-triazine-2,4,6-(1H,3H,5H)
-trione] is m-xylene-α,α′-diyl-
Bis[3,5-di-(2-propenyl)-1,3,
5-triazine 2,4,6-(1H,3H,5H)-
Trion] polyolefin composition. 4 In the polyolefin composition according to claim 1, xylene-α,α'-diyl-bis[3,5-di-(2-propenyl)-1,3,5
-Triazine-2,4,6-(1H,3H,5H)-
trione] is p-xylene-α,α′-diyl-bis[3,5-di-(2-propenyl)-1,3,5
-Triazine-2,4,6-(1H,3H,5H)-
Trion] polyolefin composition.