JPS63309539A - Production of crosslinked ethylene polymer - Google Patents

Abstract

PURPOSE:To produce the title noncolored polymer excellent in mechanical strengths and heat-resistant rigidity, by melt-kneading a specified ethylene polymer with a zinc salt of a carboxylic acid, a phenolic antioxidant and a radical generator. CONSTITUTION:100pts.wt. ethylene polymer [e.g., (non)crystalline ethylene/ propylene copolymer] (A) containing at least 5ppm Ti component as a catalyst residue or at least 0.5ppm V component as a catalyst residue and having an ethylene content >=50wt.% is mixed with 0.01-1pt.wt. zinc salt of a carboxylic acid (B) (e.g., zinc acetate), 0.01-1pt.wt. phenolic antioxidant (C) (e.g., 2,6-di-t- butyl-p-cresol) and 0.001-0.5pt.wt. radical generator [e.g., 2,5-dimethyl-2,5-di-(t- butylperoxy)hexane], and the mixture is melt-molded at 150-300 deg.C.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing a crosslinked ethylene polymer.

More specifically, (1) the titanium content of the catalyst residue is reduced to 5 ppp.
A specific amount of a phenolic antioxidant and a zinc salt of carboxylic acid are added to an ethylene polymer containing 0.5 ppm or more of vanadium or a vanadium content of 0.5 ppm or more.

) and a radical generator at a temperature of 150°C to 30°C.
(2) blending specific amounts of a phenolic antioxidant and a radical generator into the ethylene polymer at a temperature of 150°C to 30°C;
A specific amount of carboxylic acid zinc salt (hereinafter referred to as compound A) is added to a crosslinked ethylene polymer that has been melt-kneaded at 0'C.
A method for producing a crosslinked ethylene polymer is provided, which is characterized by blending and melt-kneading the mixture at a temperature of 150°C to 300°C.

[Prior Art] Generally, ethylene polymers are relatively inexpensive and have excellent mechanical properties, so they are used to manufacture various molded products such as injection molded products, blow molded products, films, sheets, and fibers. There is. However, ethylene polymers are molded at temperatures above the melting point of the ethylene polymer, but they undergo oxidative deterioration due to the heat during melt-kneading, causing problems with coloration and odor. There are also problems with thermal stability.

For this reason, in order to prevent thermal oxidative deterioration during melt-kneading, 2,6-di-t-butyl-ρ-cresol (B
) IT) is a low molecular weight phenolic acid inhibitor such as
In addition, high molecular weight phenolic antioxidants are widely used to provide thermal stability during practical use. The phenolic antioxidant is oxidized to form a phenoxy coordination complex by a titanium or vanadium complex compound that is a catalyst residue in the ethylene polymer, or the phenolic antioxidant is oxidized to produce a quinone compound, resulting in ethylene. Problems such as coloring of the system polymer occur. For this reason, a polyolefin composition in which a zinc salt of an organic acid is blended with a polyolefin (Plastics Age, Vol. 33, No. 1, 152)
~159 pages (1987 edition) [Plastics
age, Vol, 33°NQ 1. p,]52-
159 (1987)) and zinc salts of carboxylic acids with the aim of obtaining greater resistance to yellowing and a higher stabilizing effect in concentrations comprising phenolic antioxidants. A stabilizer system and a stabilized polymer composition containing this stabilizer system (JP-A-62-43437) have been proposed.

In addition, in order to improve the mechanical strength and heat-resistant rigidity of ethylene-based polymers, ethylene-based polymers are melt-kneaded in the presence of radical generators or irradiated with high-energy rays such as electron beams, X-rays, and radiation. The method of crosslinking ethylene polymers by carrying out this process is well known. In addition, amorphous ethylene-α-olefin copolymer or amorphous ethylene-α-olefin copolymer using a transition metal salt of an organic carboxylic acid as a vulcanization accelerator
- Vulcanization or crosslinking methods for olefin-nonconjugated polyene copolymers have been proposed (JP-A-49-131237 and JP-A-50-41946).

In the process of researching the coloring properties of ethylene polymers containing a large amount of titanium or vanadium as catalyst residues, the present inventors discovered that ethylene polymers containing large amounts of titanium or vanadium as catalyst residues Even if the above-mentioned phenolic antioxidant is blended and melt-kneaded, coloring does not occur to the extent that it becomes a practical problem.
It has been found that when crosslinked by melt-kneading in the presence of a radical generator, the resulting crosslinked ethylene polymer is significantly colored. This phenomenon is described in the above-mentioned Plastics Age, Vol. 33, No. 1, pp.]52-59 (1987 edition).
, JP-A-62-43437, JP-A-49-131
No. 237 and Japanese Unexamined Patent Publication No. 50-41946 do not contain any description, and there is no description even suggesting the above phenomenon. In view of the above problems, the present inventors have developed a method that does not have coloring first. For the purpose of obtaining a crosslinked ethylene polymer, a polyol or a partial ester of a polyol and a fatty acid and a phenolic antioxidant are blended into the ethylene polymer and subjected to fI4I4 edge treatment in the presence of a radical generator. Manufacturing method for combination (patent application 1986/
No. 155599) was proposed.

[Problems to be Solved by the Invention] The present inventors were not satisfied with the method for producing a crosslinked ethylene polymer previously proposed in Japanese Patent Application No. 155599/1982, and so In order to improve the mechanical strength and heat-resistant rigidity of an ethylene-based polymer containing a large amount of ethylene-based polymer mixed with a phenolic antioxidant, it is cross-linked by melt-kneading in the presence of a radical generator. We also conducted further research into methods for obtaining crosslinked ethylene polymers without coloration. the result,
(1) A specific amount of a phenolic antioxidant and a zinc salt of carboxylic acid (hereinafter referred to as compound A) are added to an ethylene polymer containing 5 ppm or more of titanium or 0.59 p or more of vanadium in the catalyst residue. ) and a radical generator, and melt-kneading the mixture at a temperature of 150°C to 300°C, and (2) blending a specific amount of a phenolic antioxidant and a radical generator into the ethylene polymer, and A specific amount of carboxylic acid zinc salt (hereinafter referred to as compound A) was blended into a crosslinked ethylene polymer that had been melt-kneaded at 150°C to 300°C, and the mixture was heated at a temperature of 15°C.
We discovered that a crosslinked ethylene polymer without coloring can be obtained by melt-kneading it again at 0°C to 300°C.
The present invention was completed based on this knowledge.

As is clear from the above description, the purpose of the present invention is (1)
Specified amounts of a phenolic antioxidant, a zinc salt of carboxylic acid (hereinafter referred to as compound A), and a radical are added to an ethylene polymer containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue. (2) blending a specific amount of a phenolic antioxidant and a radical generator into the ethylene polymer and melt-kneading the mixture at a temperature of 150°C to 300°C; A specific amount of zinc salt of carboxylic acid (hereinafter referred to as compound A) was blended into a crosslinked ethylene polymer that had been melt-kneaded at ~300°C, and the mixture was heated to 150°C.
It is an object of the present invention to provide a method for producing a crosslinked ethylene polymer without coloration by melting and milling it again at ~300°C.

[Means for solving problems] The present invention has the following configuration.

(1) Zinc salt of carboxylic acid (hereinafter referred to as compound A) and phenolic oxidation are added to 100 parts by weight of an ethylene polymer containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue. 0.01 to Ili parts of the inhibitor and 0.00 part of the radical generator, respectively.
1. A method for producing a crosslinked ethylene polymer, comprising blending 1 to 0.5 parts by weight and melt-kneading the mixture at 150°C to 300°C.

(2) 0.01 to 1 part by weight of phenolic antioxidant and radical Generating agent 0.001
A zinc salt of carboxylic acid (hereinafter referred to as compound A) was added to the crosslinked ethylene polymer which was blended with ~0.5 parts by weight and melt-kneaded at 150°C to 300°C.
A method for producing a crosslinked ethylene polymer, which comprises blending 0.01-1 parts by weight to 11 parts of 001t and melt-kneading the mixture at 150°C to 300°C.

The ethylene polymer used in the production method of the present invention has a catalyst residue with a titanium content of 5 ppm or more or a vanadium content of 0.
．． Ethylene-based materials containing 5 ppm or more, for example, obtained by solution polymerization using a saturated hydrocarbon solvent, bulk polymerization, gas phase polymerization, or a polymerization method combining bulk polymerization and gas phase polymerization. It is a polymer. In the production method of the present invention, the content of titanium in the catalyst residue is less than 5 ppph 1, or the content of vanadium is 0.5.
There is no problem even if less than ppm of the ethylene polymer is used, but in this case, even if the above-mentioned compound A is not blended, the resulting crosslinked ethylene polymer will not be colored to the extent that it becomes a practical problem. 0 The ethylene polymer used in the present invention is an ethylene polymer containing 5 ppm+ or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue, an ethylene homopolymer, or an ethylene polymer with an ethylene component of 50 wt. % or more of ethylene and propylene, butene-1, pentene-1,4-methyl-pentene 11
1 of α-olefins such as hexene-11 octene-1
Crystalline, low-crystalline or amorphous copolymers with a species or two or more species, amorphous ethylene-propylene-nonconjugated diene copolymers, copolymers of ethylene with vinyl acetate or acrylic esters, or Examples include saponified copolymers, copolymers of ethylene and unsaturated carboxylic acids or their anhydrides, and reaction products of these copolymers with metal ion compounds. Not only can they be used alone, but also two or more ethylene polymers can be used in combination. In addition, the above-mentioned polymers and various synthetic rubbers (e.g. polybutadiene, polyisoprene, polychloroprene, chlorinated polyethylene,
Chlorinated polypropylene, fluororubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer ,
(styrene-propylene-butylene-styrene block copolymers, etc.) or thermoplastic synthetic resins (e.g., polyolefins other than ethylene polymers such as polypropylene, polybutene, poly-4-methylpentene-1, polystyrene, styrene-acrylonitrile copolymers) It is also possible to use a mixture of acrylonitrile-butadiene-styrene copolymer, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinyl chloride, fluororesin, etc.). Ethylene homopolymer, crystalline or amorphous ethylene-propylene copolymer, crystalline ethylene-butene-1 copolymer, crystalline ethylene-propylene-butene-1 ternary copolymer, crystalline ethylene-pentene-1 Particularly preferred are copolymers, crystalline ethylene-hexene-1 copolymers, and mixtures of two or more of these, including ethylene polymers containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue. preferable.

Used in the present invention (i Compound A is zinc acetate, n-
Zinc propionate, n-zinc butyrate, n-valerate, n
-Zinc hexanoate, zinc n-octoate, zinc 2-ethylhexanoate, zinc n-decanoate, zinc laurate, zinc myristic, zinc palmitate, zinc stearate, zinc oleate, zinc linoleate, lylunic acid Zinc fatty acids such as zinc, zinc behenate, zinc erucate, zinc lignocerate, zinc cerotate, zinc montanate, zinc triphenylacetate, zinc oxalate, zinc malonate, zinc succinate, zinc glutarate, zinc adipate. Zinc aliphatic dicarboxylate, zinc naphthenate, zinc benzoate, etc.
Zinc 0-toluate, so-called zinc toluate, zinc p-toluate, zinc pt-butylbenzoate, zinc 0-methoxybenzoate, zinc methoxybenzoate, zinc anisate, zinc phthalate, isophthalic acid. Zinc aromatic carboxylates such as zinc acid and zinc terephthalate can be exemplified, and zinc fatty acids such as zinc 2-ethylhexanoate, zinc stearate and zinc montanate are particularly preferred. Of course, zinc salts of these carboxylic acids can be used alone. However, zinc salts of two or more carboxylic acids can also be used together. Examples of phenolic antioxidants include 2,6-di-t-butyl-p-cresol, 2-t-butyl-4,6-dimethylphenol, and 2-t-butyl-p-cresol.
, 6-di-t-butyl-4-ethylphenol, 2,6
-di-t-butyl-4-n-butylphenol, 2,6
-di-i-butyl-4-n-butylphenol, 2,6
-di-cyclopentyl-4-methylphenol, 2-(
α・Methylcyclohexyl') -4,6-dimethylphenol, 2,6-di-octadecyl-4-methylphenol, 2,4.6-)dicyclohexylphenol, 2,6-di-t-butyl-4- Methoxymethylphenol, n-octadecyl-β-(4'-hydroxy-3
',5'-di-t-butylphenyl)propionate,
2,6-diphenyl-4-octadecyloxyphenol, 2,4.6-)lis(3',5'-di-t-butyl-4'-hydroxybenzylthio)-1,3,5-triazine, 2,6-di-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone, 2,
5-di-t-amylhydroquinone, 2,29-thio-
Bis-(6-t-butyl-4-methylphenol), 2
゜2'-thio-bis-(4-octylphenol), 2
．． 2'-thio-bis-(6-t-butyl-3-methylphenol), 4,4'-thio-bis-(6-t-butyl-2-methylphenol), 2,2'-methylene-bis -(6-t-butyl-4-methylphenol), 2,2
'-methylene-bis-(6-t-butyl-4-ethylphenol), 2.2'-methylene-bis-[4-methyl-6-(α-methylcyclohexyl)-phenol],
2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis-(
6-nonyl-4-methylphenol), 2,2'-methylene-bis-[6-(α・methylbenzyl)-4-nonylphenol], 2,2'-methylene-bis-[6-(
α,α-dimethylbenzyl)-4-nonylphenol]
, 2,2'-methylene-bis-(4,6-di-t-butylphenol), 2,2'-ethylidene-bis-(4,
6-di-t-butylphenol), 2,2'-ethylidene-bis-(6-t-butyl-4-1-butylphenol), 4,4'-methylene-bis-(2,6-di-t.
butylphenol), 4,4'-methylene-bis-(6
-t-butyl-2-methylphenol>, 4,4'-butylidene-bis-(6-t-butyl-2-methylphenol), 4,4'-butylidene-bis-(6-t-butyl-3 -methylphenol), 4,4'-butylidene-
Bis-(2,6-di-t-butylphenol), 4,4
'・Butylidene-bis-(3,6-di-t-butylphenol), 1,1-bis-(5-t-butyl-4-hydroxy-2-methylphenyl)-butane, 2,6-di-
(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,! , 1.3-tris-(
5-tert-butyl-4-hydroxy-2-methylphenyl)-butane, bis[3,3-bis(4'-hydroxy-
3″-t-butylphenyl)butyric acid] ethylene glycol ester, di(3-t-butyl-4-
hydroxy-5-methylphenyl)-dicyclopentadiene, di[2-(3'-t-butyl-2'-hydroxy-5' methylbenzyl)-6-t-butyl 4-methylphenyl] terephthalate, 3,9-bis[1,l
-dimethyl-2-(β-(3-t-butyl-4-hydroxy・5-methylphenyl)probionyloxy)ethyl] -2,4,8,10-tetraoxaspiro[5,
5-oundecane, 3,9-bis[1,1-dimethyl-2
-(β-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl] -2,4,8
, 10-tetraoxaspiro[5,5]undecane, 3
,9-bis[1,1-dimethyl-2-(β-(3,5-
diphenyl-4-hydroxyphenyl)propionyloxy)ethyl-2.4,8.10-tetraoxaspiro[5,5-oundecane, 3.9-bis[1,1-dimethyl-2-(β-(3,5- dicyclohexyl-4-hydroxyphenyl)propionyloxy)ethyl]-2
．． 4,8.10-tetraoxaspiro[5,5]undecane, 1,3.5-)dimethyl-2,4,'6'-tris(3,5-di-t-butyl-4-hydroxybenzyl) Benzene, 1,3.5-tris-(3,5-di-t
-butyl-4-hydroxybenzyl)isocyanurate, 1,3.5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,
1,3,5-tris-[(3,5-di-t-butyl-4
-hydroxyphenyl)propionyloxyethyl]isocyanurate and tetrakis[methylene-3-(3
An example is ',5'-di-t-butyl-4'-hydroxyphenyl)propionate comethane. These phenolic antioxidants can of course be used alone, and two or more types of phenolic antioxidants can also be used in combination. The compounding ratio of the compound is 0.01 to 1 part by weight, preferably 0.05 to 0.00 parts by weight, per 100 parts by weight of the ethylene polymer.
5 parts by weight. If the content is less than 0.01 part by weight, the coloring prevention effect of the crosslinked ethylene polymer will not be sufficiently exhibited, and although it is OK to exceed 1 part by weight, no further improvement in the coloring prevention effect can be expected and in practice Not only is it unsuitable, but it is also uneconomical. The blending ratio of the phenolic antioxidant is 0.01 to 100 parts by weight of the ethylene polymer.
1 part by weight, preferably 0.05 to 0.5 part by weight.

If the amount is less than 0.01 part by weight, the effect of preventing thermal oxidative deterioration of the crosslinked ethylene polymer will not be sufficiently exhibited, and although it may be more than 1 part by weight, the effect of preventing further thermal oxidative deterioration will not be exhibited. Not only is it impractical as no improvement can be expected, but it is also uneconomical.

For the radical generator used in the present invention, in order to obtain a uniform composition, it is desirable that the decomposition temperature is not too low.
The temperature for obtaining a half-life of 10 hours is 70°C or higher, preferably 100°C or higher, and benzoyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2,5 -di-methyl-2゜5-di-(benzoylperoxy)hexane, 2,5-di-methyl-2,5-di-(benzoylperoxy)hexyne-3, t-butyl-di-peradipate, t-butylperoxy-3,5
, 5-) dimethylhexanoate, methyl-ethylketone peroxide, cyclohexanone peroxide,
Di-7-butyl peroxide, dicumyl peroxide, 2,5-di-methyl-2,5-di-(t-butylperoxy)hexane, 2,5-di-methyl-2,5-
Di-(t-butylperoxy)hexyne-3,1,3-
Bis-(t-butylperoxyisopropyl)benzene, t-butylcumyl peroxide, 1,1-bis-
(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis-(t-butylperoxy)cyclohexane, 2,2-bis-(t-butylperoxy)butane, p-menthane hydroperoxide,
Di-isopropylbenzene hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, p-cymene hydroperoxide,
Examples include organic peroxides such as 1,1,3.3-tetra-methylbutyl hydroperoxide and 2,5-di-methyl-2,5-di-(hydroperoxy)hexane, particularly 2,5 -di-methyl-2,5-di-(t-butylperoxy)hexane, 2,5-di-methyl-2,
5-di-(1-butylperoxy)hexyne-3 and 1,3-bis=(t-butylperoxyisopropyl)
Benzene is preferred. These radical generators can be used alone, or two or more radical generators can be used in combination. The mixing ratio of the radical generator is usually 0.001 parts to ethylene polymer + 00 fl ffi parts.
-0.5 parts by weight, preferably 0.01-0.2 parts by weight.

The melt-kneading process is carried out at a temperature of 150°C to 300"C5, preferably 180°C to 270°C, using various melt-kneading apparatuses or molding apparatuses described below. was not performed and 300'C
Exceeding this accelerates thermal oxidative deterioration of ethylene polymers
This is not preferable because the ethylene polymer becomes noticeably colored.

In the production method of the present invention, the titanium content of the catalyst residue used is 5 ppm or more, or the vanadium content is 0.5 ppm.
Various additives that are normally added to ethylene polymers, such as thioether-based, phosphorus-based antioxidants, light stabilizers, clarifying agents, nucleating agents, lubricants, antistatic agents, etc. , antifogging agents, anti-blocking agents, dropless agents, pigments, heavy metal deactivators (copper anti-toxic agents), dispersants or neutralizing agents such as metal soaps, inorganic fillers (e.g. talc, mica, clay, Wollastonite, zeolite, asbestos, calcium carbonate, aluminum hydroxide,
Surface treatment agents such as magnesium hydroxide, barium sulfate, calcium silicate, glass fiber, carbon 1a fiber, etc.) or coupling agents (such as silane, titanate, boron, aluminate, zircoaluminate, etc.) The surface-treated inorganic filler or organic filler (
(e.g. wood flour, valves, waste paper, synthetic a-fibers, natural fibers, etc.)
These can be mixed and used within a range that does not impair the purpose of the present invention. In particular, when a phosphorus-based antioxidant is used in combination, a synergistic coloring prevention effect is exhibited, so it is preferable to use them together. Preferred phosphorus antioxidants include distearyl pentaerythritol diphosphite and tetrakis (
2,4-di-t-butylphenyl)-4,4'-biphenylene-diphosphonite, bis(2,4-di-t
-butylphenyl)-pentaerythritol-shiphosphite, bis(2,6-di-t-butyl-4-methylphenyl)-pentaerythritol-shiphosphite and tris(2,4-di-t-butylphenyl) An example is phosphite.

The manufacturing method of the present invention includes (1) reducing the titanium content of the catalyst residue to 5 pl;
) Predetermined amounts of the compound A, a phenolic antioxidant, a radical generator, and the various additives mentioned above that are usually added to ethylene polymers are added to an ethylene polymer containing 1 or more or 0.5 ppm or more of vanadium. Using a normal mixing device such as a Hensel mixer (trade name), a super mixer, a ribbon blender, a panburi mixer, a tumbler, etc., mix at a temperature that does not decompose the blended radical generator to form a mixture. Using various melt kneading devices such as ordinary single screw extruder, twin screw extruder, Brabender or roll, melt kneading temperature is 150℃~300℃.
℃, preferably 180℃ to 270℃ to form pellets, or (2) the titanium content of the catalyst residue is 5 ppm or more or the vanadium content is 0.5p.
Predetermined amounts of a phenolic antioxidant, a radical generator, and the above-mentioned various additives that are normally added to ethylene polymers are added to the ethylene polymer containing pm or more using a conventional mixing device such as a Hensel mixer (trade name), Using a super mixer, ribbon blender, Pan Bali mixer, tumbler, etc., mix at a temperature that does not decompose the blended radical generator to form a mixture. Using various melt-kneading devices such as Brabender or roll, the melt-kneading temperature is 150°C to 300°C.
℃, preferably 180℃ to 270℃ to form pellets, and to the pellets, a predetermined amount of the compound A1, preferably a mixture or pellets containing a high concentration of compound A in an ethylene polymer, in the form of a so-called masterbatch. Compound A is mixed using a conventional heating device such as a Hensel mixer (trade name), a super mixer, a ribbon blender, a panburi mixer, a tumbler, etc., and the mixture is processed using a conventional single-screw extruder, Various melt kneading devices such as twin-screw extruders, Brabenders or rolls,
Or, using various molding equipment such as a spinning machine, a film forming machine, an injection molding machine, or a blow molding machine, the melt-kneading temperature is 150°C or more.
This is carried out by melt-kneading at 300°C, preferably from 180°C to 270°C, followed by pelletizing or molding.

[Function] In the present invention, the phenolic antioxidant acts as a radical chain inhibitor, and the radical generator generates radicals by melt-kneading, that is, heating, and extracts hydrogen atoms from the ethylene polymer. It is well known that it generates radicals and crosslinks ethylene polymers, thereby improving mechanical strength, heat-resistant rigidity, etc.

In the production method of the present invention, when the above-mentioned compound A is crosslinked by melt-kneading an ethylene polymer stabilized with a phenolic antioxidant in the presence of a radical generator, a titanium or vanadium complex is formed. Although the mechanism of action itself is not clear as to how it acts on the compound, Compound A acts on the complex compound of titanium or vanadium to produce a stable chelate compound, that is, it deactivates the active titanium or vanadium → , and a colored compound formed by a titanium or vanadium complex compound when Compound A crosslinks an ethylene polymer stabilized with a phenolic antioxidant by melt-kneading it in the presence of a radical generator. It is presumed that the compound A acts on the phenoxy coordination complex, and the zinc of the compound A substitutes for titanium or vanadium in the phenoxy coordination complex, producing a colorless phenoxy-zinc coordination complex.

[Effects of the Invention] The crosslinked ethylene polymer obtained by the production method of the present invention is disclosed in the above-mentioned Japanese Patent Application No. 1555/1988 filed by the present inventors.
Compared to the crosslinked ethylene polymer related to No. 99, it is not colored and has improved mechanical strength and heat-resistant rigidity, so it can be used in various methods such as injection molding, transport molding (especially wire coating, foaming), blow molding, etc. It can be suitably used for producing desired molded products by a molding method.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The evaluation method used in Examples and Comparative Examples was as follows.

Colorability: Y I (Yellow
The colorability was evaluated based on the magnitude of this YI value.

The smaller this number is, the less coloring there is.

Examples 1 to 15, Comparative Examples 1 to 7 As an ethylene polymer, old (load 2 at 190°C
．． Powdered Ziegler-Natsuta ethylene homopolymer (titanium content: 8 ppm) 10
0 parts by weight of compound A, zinc 2-ethylhexanoate, zinc stearate, zinc montanate or zinc benzoate, phenolic acid (2,6-di-t as a P inhibitor)
-butyl-p-cresol, tetrakis[methylene-3
-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate comethane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl) −
4-hydroxybenzyl)benzene, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate or n-octadecyl-β-(
4'-hydroxy-3', 5'-di-monobutylphenyl) propionate, 2,5- as a radical generator
The prescribed amounts of di-methyl-2,5-di-(t-butylperoxy)hexane or 1,3-bis-(t-butylperoxyisopropyl)benzene and other additives are shown in Table 1 below. Pour the mixture into a Hensel mixer (trade name) at the listed mixing ratio and stir and mix for 3 minutes.
The mixture was melt-kneaded and crosslinked at 200° C. using a single-screw extruder (mm) to form pellets. Also, as Comparative Examples 1 to 7, the old one is
．． 100 parts by weight of powdered Ziegler-Natsuta ethylene homopolymer (titanium content 8 ppm) at 5 g/10 min were blended with predetermined amounts of each of the additives listed in Table 1 below. A crosslinked pellet was obtained by melt-kneading in accordance with the above.

The obtained pellets were used to evaluate the colorability according to the test method described above. These results are shown in Table 1.

Examples 16 to 30, Comparative Examples 8 to 14 As an engineered ethylene polymer, a powdered Ziegler-Natsuta ethylene-propylene copolymer (3.0 methyl branches/1000 carbons, Titanium content: 8 ppm) 100 parts by weight, 2-
Zinc ethylhexanoate, zinc stearate, zinc montanate or zinc benzoate, 2,6-di-t-butyl-p-cresol, tetrakis[methylene-3-(3',5'- di-t-butyl-
4'-hydroxyphenyl)propionate comethane,
1゜3.5-)Listyl-2,4,6-)Listyl(3,5
-di-t-butyl-4-hydroxybenzyl)benzene, 1,3.5-tris-(3,5-di-t-butyl-4
-hydroxybenzyl)isocyanurate or n-octadecyl-β-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, as radical generator 2,5-di-methyl-2,5- di-t-butylperoxy)hexane or 1,3-bis-(t-
Butylperoxyisopropyl) benzene and other additives in predetermined amounts were put into a Hensel mixer (trade name) at the mixing ratios listed in Table 2 below, and after stirring and mixing for 3 minutes, a single screw extruder with a diameter of 40 m was used. The mixture was melt-kneaded at 200° C. to crosslink and form pellets. In addition, Comparative Example 8~
As for 14, the old one is 0.5g 710 minutes of powdered Ziegler.
Natsuta-based ethylene/propylene copolymer with methyl branch 3
．． 0 pieces/1000 coal industry, titanium content 8 ppw+)
Predetermined amounts of the additives listed in Table 2 below were added to 100 parts by weight, and the mixture was melt-kneaded in accordance with Examples 16 to 30 to obtain crosslinked pellets.

Using the obtained pellets, colorability was evaluated according to the test method described above. These results are shown in Table 2.

Examples 31 to 45, Comparative Examples 15 to 21 As an engineered ethylene polymer, powdered Ziegler Natsuta type ethylene-butene-1 copolymer (ethyl branches 0.014 pieces/10 minutes) 1000 carbon, vanadium content 0.6 ppo+) 100 parts by weight, zinc 2-ethylhexanoate, zinc stearate, zinc montanate or zinc benzoate as compound A, and 2,6-di-t as a phenolic antioxidant. -butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-t.butyl-4'-hydroxyphenyl)propionate comethane, 1.3.5-trimethyl-2,4,6 −
) Lis(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3.5-tris-(3,5-di-
t-Butyl-4-hydroxybenzyl) isocyanurate or n-octadecyl β-(4'-hydroxy-
3',5'-di-t-butylphenyl)propionate, 2,5-di-methyl-2゜5- as a radical generator
di-(t-butylperoxy)hexane or l,3
-Bis-(t-butylperoxyisopropyl)benzene and other additives in predetermined amounts were placed in a Hensel mixer (trade name) at the mixing ratios listed in Table 3 below, and after stirring and mixing for 3 minutes, the caliber 20 with a 40-gu single-screw extruder
The mixture was melt-kneaded at 0° C. to crosslink and pelletize.

In addition, as Comparative Examples 15 to 21, powdered Ziegler-Natsuta ethylene-butene-1 copolymer (0.014 ethyl branches/1000 carbon, vanadium content o, epp-) 100 Predetermined amounts of additives listed in Table 3 below were added to the parts by weight, and crosslinked pellets were obtained by melt-kneading according to Examples 31 to 45.

Using the obtained pellets, the colorability was evaluated by the test method described above. These results are shown in Table 3.

Examples 46 to 60, Comparative Examples 22 to 28 Mooney viscosity ML1+4(1
00°C) 25 powdery amorphous ethylene-propylene copolymer (propylene content 25%, vanadium content 0.
6 ppm) 100 parts by weight, zinc 2-ethylhexanoate, zinc stearate, zinc montanate or zinc benzoate as compound A, 2,6-di-t-butyl-p-cresol, tetrakis as a phenolic antioxidant. [Methylene-3-(3',5'-di-t.butyl-4'
-Hydroxyphenyl)propionate comethane, 1,
3゜5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,
1.3.5-tris-(3,5-di-t-butyl-4
-hydroxybenzyl)isocyanurate or n-octadecyl-β-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, 2,5-di-methyl-2,5- di-(t-butylperoxy)hexane or 1,3-bis-(t-
Butylperoxyisopropyl)benzene and other additives in predetermined amounts were put into a Hensel mixer (trade name) at the mixing ratios listed in Table 4 below, and after stirring and mixing for 3 minutes, single-screw extrusion with a diameter of 40m+* was carried out. The mixture was melt-kneaded in a machine at 200°C to crosslink and form pellets. In addition, as Comparative Examples 22 to 28, Mooney viscosity ML1+4 (100°C)
is 25 powdery amorphous ethylene-propylene copolymer (
Propylene content 25%, vanadium content 0.6pp
m) 100 parts by weight were blended with predetermined amounts of each of the additives listed in Table 4 below, and melt-kneaded according to Examples 46 to 60 to obtain crosslinked pellets.

Using the obtained pellets, colorability was evaluated according to the test method described above. These results are shown in Table 4.

Examples 61 to 75, Comparative Examples 29 to 35 As an engineered ethylene polymer, 100 parts by weight of a powdered Ziegler-Natsuta ethylene homopolymer (containing titanium 18 ppm) was added to 1.5 g/10 minutes of phenolic polymer. 2,6-di-t-butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-
t-Butyl-4'-hydroxyphenyl)propionate comethane, 1.3.5-)listyl-2,4,6-)
Lis(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3.5-)lis-(3,5-di-
t-Butyl-4-hydroxybenzyl)isocyanurate or n-octadecyl-β-(4'-hydroxy-
3',5'-di-t-butylphenyl)propionate, 2,5-di-methyl-2゜5- as a radical generator
Di-(t-butylperoxy)hexane or 1.3
-Bis-(t-butylperoxyisopropyl)benzene and other additives in predetermined amounts were put into a Hensel mixer (trade name) at the mixing ratios listed in Table 5 below, and after stirring and mixing for 3 minutes, the caliber 20 with a 40-inch single screw extruder
The mixture was melt-kneaded and crosslinked at 0° C. to obtain pellets (hereinafter abbreviated as pellets ①). Obtained pellets))9
0 parts by weight, 1.5 g/10 min of powdered Ziegler-Natsuta ethylene homopolymer (titanium content: 8 p)
pm) and predetermined amounts of each of zinc 2-ethylhexanoate, zinc stearate, zinc montanate, or zinc benzoate as Compound A in the blending ratios listed in Table 5 below. )put in,
After stirring and mixing for 1 minute, use a single-screw extruder with a diameter of 40 mm to
The pellets are melt-kneaded at ℃ and are hereinafter abbreviated as pellets. ) was obtained. In addition, as Comparative Examples 29 to 35, the former was 1.5 g/10 minutes of powdered Ziegler-Natsuta ethylene homopolymer (titanium content 418 ppm) 100
Add a predetermined amount of each of the additives listed in Table 5 below to 1.1 part in a Hensel mixer (trade name) at the mixing ratio listed in Table 5 below, stir and mix for 3 minutes.
Crosslinked pellets (hereinafter abbreviated as pellets I) were obtained by melt-kneading at 200° C. using a 0 mm single-screw extruder. To 190 parts by weight of the obtained pellet, 1.5 g/g of old was added.
10 parts by weight of a 10-minute powdered Ziegler-Natsuta ethylene homopolymer (titanium content 8 ppm) and predetermined amounts of each of the additives listed in Table 5 below at the blending ratios listed in Table 5 below. Hensel mixer (product name)
After stirring and mixing for 1 minute, melt-kneading was performed at 200°C using a single-screw extruder with a diameter of 40 m+s to form pellets (hereinafter referred to as
Peret) II. ) was obtained.

Using the obtained pellets I and Pellet II, colorability was evaluated according to the test method described above. The results are shown in Table 5.

Examples 76 to 90, Comparative Examples 36 to 42 Mooney viscosity ML++4 (1
00°C) 25 powdery amorphous ethylene-propylene copolymer with a propylene content of 25% and a vanadium content of 0.
6 ppm) Too many parts by weight of 2,6-di-t-butyl-p-cresol, tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxy) as a phenolic antioxidant. phenyl) propionate comethane, 1,3,5-) listyl-2,4,6-) lys(3
, 5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3.5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate or n
-Tadecyl-β-(4'-hydroxy-3',5''
-di-t-butylphenyl) propionate, 2,5-di-methyl-2,5-di-(t-
butylperoxy)hexane or 1,3-bis-(
t-Butylperoxyisopropyl) benzene and other additives in the proportions shown in Table 6 below were placed in a Hensel mixer (trade name), stirred and mixed for 3 minutes, and then The mixture was melt-kneaded and crosslinked at 200° C. in a screw extruder to obtain pellets (hereinafter abbreviated as pellets I). To 90 parts by weight of the obtained Beret) I was added 10 parts of a powdery amorphous ethylene-propylene copolymer (propylene content FF 125%, vanadium content 0.6 ppm) having a Mooney viscosity ML1+4 (100°C) of 25.
Parts by weight and predetermined amounts of zinc 2-ethylhexanoate, zinc stearate, zinc montanate, or zinc benzoate as compound A are placed in a Hensel mixer (trade name) at the mixing ratios listed in Table 6 below, After stirring and mixing for 1 minute, the mixture was melt-kneaded at 200° C. using a single-screw extruder with a diameter of 40 mm to obtain a pellet (hereinafter abbreviated as pellet ①). Further, as Comparative Examples 36 to 42, a powdery amorphous ethylene-propylene copolymer (propylene content 25%, vanadium content f10.6 ppm) having a Mooney viscosity ML1+4 (100° C.) of 25 was used. Add a predetermined amount of each of the additives listed in Section 6 below to 1 part of the Hensel mixer (trade name) at the mixing ratio listed in Table 6 below.
After stirring and mixing for 3 minutes, the crosslinked pellets were melt-kneaded at 200°C in a single-screw extruder with a diameter of 40 mm.
Hereinafter, it will be abbreviated as Penta)I. ) was obtained. Mooney viscosity ML1+4 (100 parts by weight) was added to 90 parts by weight of the obtained pellet I.
Powdered amorphous ethylene-propylene copolymer (propylene content 25%, vanadium content 0.6
After putting 10 parts by weight of 10 parts by weight of 10 parts by weight of 10 parts by weight of each of the additives listed in Table 6 below into a Hensel mixer (trade name) at the mixing ratios listed in Table 6 below, and stirring and mixing for 1 minute. The pellets were melt-kneaded at 200° C. using a single-screw extruder with a diameter of 40 mm (hereinafter abbreviated as pellets ①).

) was obtained.

Using the obtained pellets I and B, the colorability was evaluated using the test method described above. The results are shown in Table 6.

The compounds and additives shown in Tables 1 to 6 are as follows.

Compound A [-1]; Zinc 2-ethylhexanoate Compound A
[n]; Zinc stearate compound Arm]; Zinc montanate compound A [■]; Zinc benzoate phenolic antioxidant [11; 2,6-di-t-butyl-p-cresol phenolic antioxidant Agent [■]; Tetrakis [methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate comethane phenolic antioxidant [II []; ]1,3.
5-trimethyl-2.46-)lis(3,5-di-t
-butyl-4-hydroxybenzyl)benzenephenolic antioxidant [IV]; 1.3.5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate phenolic antioxidant [ V; n-octadecyl-β
-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate radical generator [11;2,5-di-methyl-2,5-
Di-(t-butylperoxy)hexane radical generator [11]; 1,3-bis-(t-butylperoxyisopropyl)benzenephosphorus antioxidant 1; Tetrakis(2,4-di-t-
butylphenyl) -4,4'-biphenylene diphosphonite phosphorous antioxidant 2; bis(2,4-di-t-butylphenyl)-pentaerythritol-siphosphite polyol compound; pentaerythritol monostear Rate zinc compound phosphate compound (zinc salt of organic phosphoric acid); Zinc stearyl phosphate (mono- and di-mixture) (Sakai Chemical Industry ■
Product name [LBT-1830) Zn○; Zinc oxide Z n S; Zinc sulfide Mg-3t; Magnesium stearate Ca-3t
Calcium Stearate The Examples and Comparative Examples listed in Table 1 are cases where a Ziegler-Natsuta ethylene homopolymer was used as the ethylene polymer. As can be seen from Table 1, in Examples 1 to 15, compound A, a phenolic antioxidant, and a radical generator were added to a Ziegler-Natsuta ethylene homopolymer containing 30 ppm of titanium in the catalyst residue according to the present invention. It is blended, melt-kneaded, and crosslinked. Examples 1 to 15 and Comparative Examples 1 to 2
(Using a phosphorus antioxidant as a coloring inhibitor) and Comparative Example 3 (Patent application filed in 1983, which was previously proposed by the present inventors)
155599, in which a partial ester of a polyol and a fatty acid, a phenolic antioxidant, and a radical generator are blended into an ethylene polymer, melt-kneaded, and cross-linked). It was found that Examples 1 to 15 had little coloration, while Comparative Examples 1 to 2, in which a phosphorous antioxidant was used instead of Compound A, had significant coloration. It can be seen that the coloring prevention property is further improved than that of Comparative Example 3 using the partial ester. Moreover, when comparing Comparative Examples 4 to 7 in which a zinc compound other than Compound A was used instead of Compound A and Examples 1 to 15, Comparative Example 4
It can be seen that the anti-coloring properties of Samples 7 to 7 were hardly improved. Further, in each example, compound A according to the present invention
In Examples 9 and 10, in which a phenolic antioxidant, a radical generator, and a phosphorus antioxidant were mixed and crosslinked by kneading, the excellent coloring prevention effect of Compound A was inhibited compared to Example 6. It can be seen that a remarkable synergistic effect can be observed due to the combined use of phosphorus antioxidants, without any negative effects.

Tables 2 to 4 use Ziegler-Natsuta ethylene-propylene copolymer, Ziegler-Natsuta ethylene-butene-1 copolymer, and amorphous ethylene-propylene copolymer as the ethylene polymers, respectively. The same effects as described above were confirmed for these as well.

Further, the Examples and Comparative Examples listed in Table 5 are cases where a Ziegler-Natsuta ethylene homopolymer was used as the ethylene polymer. As can be seen from Table 5, in Examples 61 to 75, the titanium content of the catalyst residue related to the present invention was 3
A phenolic antioxidant and a radical generator are blended into a Ziegler-Natsuta ethylene homopolymer containing 0 ppm, and compound A is blended into a crosslinked ethylene polymer that is melt-kneaded and then melt-kneaded again. be. Comparing Examples 61 to 75 and Comparative Examples 29 to 35 (using a phosphorous antioxidant, a partial ester of polyol and fatty acid, or a zinc compound other than Compound A in place of Compound A), Example 61 It can be seen that although the coloring of the pellets (2) of No. 75 is significant, the coloring of the pellets (2) obtained by using compound A is significantly improved. In contrast, Comparative Examples 29 to 35
Co-coloring of pellets) I and pellets ■ is remarkable, especially pellets ■ obtained by using a phosphorus-based acid inhibitor, a partial ester of a polyol and a fatty acid, or a zinc compound other than compound A in place of compound A. It can be seen that not only the coloring prevention property was not improved, but also that the material was significantly colored due to being subjected to two melt-kneading treatments, that is, heat history.

In Table 6, an amorphous ethylene-propylene copolymer was used as the ethylene polymer, and the same effects as in Table 5 were confirmed for this as well.

Therefore, it can be seen that the crosslinked ethylene polymer obtained by the production method of the present invention is free from coloration and has improved mechanical strength, heat-resistant rigidity, and the like.

Therefore, the crosslinked ethylene polymer obtained by the production method of the present invention is prepared by blending a compound with a conventionally known anti-coloring effect and a phenolic antioxidant, and melt-kneading the mixture in the presence of a radical generator. A compound that has a conventionally known anti-coloration effect is blended with a crosslinked ethylene polymer that has been crosslinked with a phenolic antioxidant, and is crosslinked by melt-kneading in the presence of a radical generator. It was found that the coloring prevention property was significantly superior to that obtained by melt-kneading, confirming the remarkable effects of the present invention.

that's all

Claims (10)

[Claims] (1) Ethylene polymer 1 containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue
00 parts by weight, 0.01 to 1 part by weight of a zinc salt of carboxylic acid (hereinafter referred to as compound A) and a phenolic antioxidant, and 0.001 to 1 part by weight of a radical generator.
A method for producing a crosslinked ethylene polymer, comprising blending 0.5 parts by weight and melt-kneading the mixture at 150°C to 300°C. (2) The method for producing a crosslinked ethylene polymer according to claim (1), wherein one or more compounds selected from zinc fatty acids and zinc aromatic carboxylates are blended as compound A. (3) 2,6-di-t- as a phenolic antioxidant
Butyl-p-cresol, tetrakis[methylene-3-
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4
-hydroxybenzyl)benzene, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate and n-octadecyl-β-(4
The crosslinked ethylene polymer according to claim (1), which contains one or more selected from '-hydroxy-3',5'-di-t-butylphenyl) propionate. manufacturing method. (4) 2,5-di-methyl-2, as a radical generator
5-di-(t-butylperoxy)hexane, 2,5-
Contains one or more selected from di-methyl-2,5-di-(t-butylperoxy)hexyne-3 and 1,3-bis-(t-butylperoxyisopropyl)benzene. A method for producing a crosslinked ethylene polymer according to claim (1). (5) Ethylene homopolymer, crystalline or amorphous ethylene-propylene copolymer containing 50% by weight or more of ethylene component, crystalline ethylene-propylene copolymer as the ethylene polymer
Butene-1 copolymer, crystalline ethylene-propylene-butene-1 tertiary copolymer, crystalline ethylene-pentene-1
One or more selected from copolymers and crystalline ethylene-hexene-1 copolymers, with a titanium content of 5 ppm or more or a vanadium content of 0 in the catalyst residue.
．． The method for producing a crosslinked ethylene polymer according to claim (1), using a polymer containing 5 ppm or more. (6) Ethylene polymer 1 containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue
0.0 parts by weight of phenolic antioxidant
1 to 1 part by weight and 0.001 to 0.00 parts by weight of the radical generator.
5 parts by weight of a crosslinked ethylene polymer was melt-kneaded at 150°C to 300°C, and 0.5 parts by weight of zinc salt of carboxylic acid (hereinafter referred to as compound A) was added to 100 parts by weight of the ethylene polymer. 01 to 1 part by weight,
A method for producing a crosslinked ethylene polymer, comprising melt-kneading at 150°C to 300°C. (7) The method for producing a crosslinked ethylene polymer according to claim (6), wherein one or more compounds selected from zinc fatty acids and zinc aromatic carboxylates are blended as compound A. (8) 2,6-di-t- as a phenolic antioxidant
Butyl-p-cresol, tetrakis[methylene-3-
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4
-hydroxybenzyl)benzene, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate and n-octadecyl-β-(4
The crosslinked ethylene polymer according to claim (6), which contains one or more selected from '-hydroxy-3',5'-di-t-butylphenyl) propionate. manufacturing method. (9) 2,5-di-methyl-2, as a radical generator
5-di-(t-butylperoxy)hexane, 2,5-
Contains one or more selected from di-methyl-2,5-di-(t-butylperoxy)hexyne-3 and 1,3-bis-(t-butylperoxyisopropyl)benzene. A method for producing a crosslinked ethylene polymer according to claim (6). (10) Ethylene homopolymer as the ethylene polymer,
Crystalline or amorphous ethylene-propylene copolymer, crystalline ethylene-butene-1 copolymer, crystalline ethylene-propylene copolymer containing 50% by weight or more of ethylene component
Butene-13 element copolymer, crystalline ethylene-pentene-
1 copolymer and crystalline ethylene-hexene-1 copolymer, containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue. A method for producing a crosslinked ethylene polymer according to claim (6).