JPS63175049A - Production of crosslinked ethylenic polymer - Google Patents

Abstract

PURPOSE:To obtain a crosslinked polymer having improved mechanical strength, heat resistance, rigidity, etc., without coloring, by blending an ethylenic polymer containing Ti or V which is a catalyst residue with specific amounts of a hindered amine based compound, phosphorus based antioxidant and radical former and melt kneading the resultant blend. CONSTITUTION:(A) 100pts.wt. ethylenic polymer containing >=5ppm Ti or >=0.5ppm V which is a catalyst residue is blended with (B) 0.05-5pts.wt. hindered amine based compound having no hydroxyl group, e.g. tetrakis(2,2,6,6- tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, (B) 0.01-1pt.wt. phospho rus based antioxidant, e.g. bis(2,4-di-tert-butylphenyl)-pentaerythritol diphosphite and (C) 0.001-0.5pt.wt. radical former and the resultant blend is melt kneaded at 150-300 deg.C, preferably 180-270 deg.C. The amounts of the blended components are preferably 0.1-1pt.wt. component (A), 0.05-0.5pt.wt. component (B) and 0.01-0.2pt.wt. component (C).

Description

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

More specifically, a hindered amine compound (hereinafter referred to as "compound") which does not have a specific h1 phenolic hydroxyl group in an ethylene polymer containing 5 ppm or more of titanium or 0,5 ppm or more of vanadium in the catalyst residue. ), relates to a method for producing a crosslinked ethylene polymer, characterized in that a phosphorus antioxidant and a radical generator are blended and melt-kneaded 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. . However, although ethylene polymers are molded at temperatures above the melting point of the ethylene polymer, they undergo oxidative deterioration due to the heat during melt-kneading, causing problems with coloration and odor, and are not suitable for practical use. There are also problems with thermal stability over time. For this reason, for the purpose of preventing thermal oxidative deterioration during melt-kneading, 2,6-di-L-butyl-p-cresol (
Low molecular weight phenolic antioxidants such as BHT) are widely used, and high molecular weight phenolic antioxidants are widely used to provide thermal stability in practical use.

However, when melt-kneading the ethylene polymer containing the above-mentioned phenolic antioxidant, the itaphenol-based antioxidant is oxidized during melt-kneading by a complex compound of titanium or vanadium, which is a catalyst residue in the ethylene-based polymer. This causes problems such as the formation of a quinone compound and the coloring of the ethylene polymer. 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 into the coalescence and melt-kneaded, coloring will not occur to the extent that it becomes a practical problem. They discovered that when crosslinked by melt-kneading in the presence of ethylene, the resulting crosslinked ethylene polymer becomes discolored. Method for producing a crosslinked ethylene polymer by blending and melt-kneading a radical generator (Japanese Patent Application No. 61-15
No. 5599) was proposed.

In addition, in order to improve the mechanical strength and heat-resistant rigidity of ethylene polymers, ethylene polymers are crosslinked by melt mixing or electron beam irradiation treatment in the presence of a radical generator. The method is well known.

[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. 61-155599, and the titanium content or vanadium content as a catalyst residue was Further intensive research was carried out on a method for obtaining a crosslinked ethylene polymer without coloration by melt-blending a ethylene polymer containing a large amount of (f) in the presence of a radical generator.

As a result, a hindered amine compound (hereinafter referred to as "compound A") containing no phenolic hydroxyl group, which is specific to ethylene polymers containing catalyst residue with a titanium content of 5 ppm or more or a vanadium content of 0.5 ppm or more, was found. ), a phosphorus-based antioxidant and a radical generator are blended and melt-kneaded to produce cross-linked ethylene that is free from coloration and has practically satisfactory thermal oxidative deterioration prevention properties during melt-kneading and thermal stability during practical use. It was discovered that a system/R combination could be obtained, and the present invention was completed based on this knowledge.

As is clear from the following description, the object of the present invention is to add Compound A1, a phosphorus antioxidant, and an ethylene polymer containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue. It is an object of the present invention to provide a method for producing a crosslinked ethylene polymer without coloration by blending a radical generator and performing a melt-kneading treatment.

[Means to solve the problem 1 The present invention has the following configuration.

The titanium content of the catalyst residue is 5 ppm or more, or the vanadium content is 0,5 ppli or more.
[To 100 parts by weight of the combined substance, 005 to 5'+H parts of a hindered amine compound (hereinafter referred to as a compound) having no phenolic hydroxyl group, and 0.01 to 1 part by weight of a phosphorus antioxidant l- , radical generator from 0.001 to
1. A method for producing a crosslinked ethylene polymer, which comprises blending 0.5 parts by weight and melt-kneading the mixture at 150°C to 300°C.

The ethylene polymer used in the production method of the present invention includes high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, etc., and contains 5 ppm or more of titanium or vanadium in the catalyst residue. 0
, 5 ppm or more, such as a solution polymerization method using a saturated hydrocarbon solvent, a bulk polymer, or a gas phase polymerization method, such as a combination of a bulk polymerization method and a gas phase polymerization method. This is an ethylene-based polymer obtained by a polymerization method using a polymerization method. In the production method of the present invention, there is no problem in using an ethylene polymer in which the titanium content (rAt) of the catalyst residue is less than 5 ppm or the vanadium content '+t is less than 0.5 ppm.The present invention The ethylene polymer to be used is an ethylene polymer containing 5 ppm or more of titanium or 0.5 ppm or more of vanadium in the catalyst residue, such as ethylene autopolymer, ethylene and propylene, butene -1, pentene-1,4-
Crystalline or non-crystalline copolymer with one or more α-olefins such as methyl-pentene-1, hexene-1, octene-1, amorphous ethylene-propylene-nonconjugated diene 1 polymer , copolymers of ethylene and vinyl acetate, acrylic esters, etc. or saponified products of these copolymers, copolymers of ethylene and unsaturated carboxylic acids and their anhydrides, and copolymers of ethylene and metal ion compounds. For example, these ethylene polymers can be used alone or in combination of two or more ethylene polymers. In addition, the above-mentioned ethylene polymers and various synthetic rubbers (e.g. polybutadiene, polyisoprene, chlorinated polyethylene, chlorinated polypropylene, styrene-butadiene rubber, styrene-
Butadiene-styrene block copolymer, styrene-isoprene-styrene block polymer, styrene-ethylene-butylene-styrene block copolymer, styrene block [l pyrene-butylene-styrene block] (polymer) or thermoplastic synthetic resins (e.g. polyolefins excluding ethylene polymers such as polypropylene, polybutene, poly-4-methylpentene-1, polystyrene, styrene-acrylonitrile consortium, acrylonitrile-butadiene-styrene copolymer, polyamide) , polyethylene terephthalate, polybutylene terephthalate, amorphous ethylene-propylene(5) ethylene polymer, ethylene-butene-1 copolymer, crystalline ethylene-propylene-butene-13-substituted ITi combination, crystalline ethylene-pene A ten-l covalent polymer, a crystalline ethylene-hexene-1j14 polymer, or a mixture of two or more of these, in which the titanium content of the catalyst residue is 5 ppm or less, or the vanadium content is 0 or 5 ppm or more. Ij″
Particularly preferred are ethylene polymers.

Compounds that may be used in the present invention include 4-human[lquin-2,2,6,6-tetramethylpiperidine, 1-allyl-4-human[lquin-2,2°6.6-tetramethylpiperidine] Methylpiperidine, l-bensyl-4-human [Tsukino 2.
2,6.6-tetramethylpiperidine, 1-(4-t-
butyl-2-butenyl)-4-human[lquin-2,2,
6,6-tetramethylpiperidine, 4-stearoyl oxine-2,2,6,6-tetramethylpiperidine, 4-
methacryloyloxy-1,2,2,6,6-bentamedylpiperidine,
, 6,6-tetramethyl-4-piberinyl) adipate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(2,2,6,6-titramedyl-4-piperidyl) fumarate, Bis (1, 2, 3,
6-thitramedyru 2.6-siethyl-4-piperidyl) sebacate, bis(■-allyru 2.2,6.ll+
-tetramedyl-4-piperidyl) phthalate, bis(
1,2,2,6,6-pentamethyl-4-piperinol)
Sebacate, ■-Propargy-4-β-cyanoethyloxo-2,2,6,6-titramedylbiperidine, ■-
Acederu 2.2,6゜6-tetramethyl-4-piperidyl-acetate, trimellitic acid tri-(2,2
,6,6-tetramethyl-4-piperidyl) ester,
1-acryloyl-4-pendyluoquine-2,2゜6.
6-tetramethylpiperidine, His(+, 2゜2, G,
6-bentamedyl-4-biperinyl)dibutylmalonate, bis(1,2,2,6,6-bentamedyl-4-piperidyl)dibenzyl-malonate, bis(1,2,3
,6-titramethyl-2,6-danityl-4-piperidyl)dibenzyl-ma[1 nate, hexane-1'6'
-bis-4-carbamoyloxy-1-n-butyl-2
, 2゜6.6-tetramethylpiperidine), toluene-
2',4'-bis-(4-carbamoyloxy-1-〇-butyl-2.2.6.6-titramethyl-biperinone), dimedyrubis(2,2,6゜6-tetramethylpiperidine-4- (oxy)-furan, phenyl-tris-
C2,2,6,G-tetramethylpiperidine-4-okyne)-butane, tris-(1-propyl-2,2,6,
6-titramedyl-4-piperidyl)-phosphite, tris-(+-propyl-2,2,6,6-tetramethyl-4-piperidyl)-phosphate, phenyl-
[, bis-(+, 2,2,6.6-pentamethyl=4-
piperidyl)-phosphate, tetrakis(2,2,
6,6-titramethyl-, 1. piperidyl) 1.2.3
．． 4-Butanetetracarboxylate, tetrakis(1
,2,2゜6.6-pentamethyl-4-piperidyl)1
, 2゜3.4-butanetetracarboxylate, di(tridecyl) bis(2,2,6,6-tetramethyl-4
-piperidyl) 1,2,3,4-butanetetracarboxylate, di(tridecyl) bis(1,2,2,6,
6-pentamethyl-4-piperidyl)1,2,3.4-
Butanetetracarboxylate, 2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro l-
5,1,11,2]heneicosan-21-one, 3,
9-bis[1,l-dimethyl-2-(tris(2,2,
6,6-titramedyl-4-piveridyloxycarponyl)butylcarbonyloxy)ethyl]-2,4,8°! 0-tetraoxaspiro[5,5]undecane, 3.
9-bis[1,1-dimethyl-2-(tris(+,2,
2,6.6-pentamethyl-4-piperidyloxycarbonyl)butylcarbonyloxy)ethyl]-2,4,
8,10-tetraoxaspiro[5,5]undecane,
dimethyl succinate-2-(4-hyperoxidase 2.2
, 6.6-titramedylbiperidyl) ethanol condensate, poly[hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl)imino-]], poly[ethylene [(2,2 ,6,6-nadramethyl-4-piperidyl)
imino]hexamethylene[(2,,2,6,6-tetramethyl-4-piperidyl)imino]], poly[[6-[
(], ]1.3.3-tetramethylbutylamino 1-1
．． 3.5-triazine-2,4-diyl E [(2,
2,e,e-tetramethyl-4-piperidyl)imino 1
hexamethylene [(2,2,6,6-tetramethyl-4
-piperidyl)imino]], poly1-[6-morpholino-1,3,5,-trianone-2,1-noyl]
[(2,2,6,6-tetramethyl-4-piperidyl)
imino 1 hexamethylene [(2,2゜6.6-tetramethyl-4-piperidyl)imino] 1, poly[[6-4
(Edylacetyl)aminoj-1,3,5-triazine-2,4-diyl][(2,2゜6.6-titramedyl-4-piperidyl)imino1hexamethylene[(2,2
,6,6-tetramethyl-4-piperidyl)iminoco]
, #≠poly[[6-[(2,2,6,6-titramedy-4-piperidyl)butylamino]-1,3,5-trianone-2,4-diyl] [(2,2,6,6 −
Examples include tetramethyl-4-piperidyl)imino1hexamethylenel(2,2,6,6-tetramethyl-4-piperidyl)imino] and mixtures of two or more thereof. In particular, tetrakis (2,2,6゜6-tetramethyl-
4-piperidyl) 1.2.34-butanetetracarboxylate, 3.9-bis[1,l-dimethyl-2-(tris(+,22,6.6-bentamedyl-4-piperidyloxycarbonyl)butylcarbonyloxy) ) ethyl]-2,4,8,10-tetraoxaspiro "5゜5"
Undecane, poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2
,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl)imino1hexamethylene[(2,2
,6,6-tetramethyl-4-piperidyl)imino]]
, poly[[6-morpholino-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperinor)imino]hexamethylene[(2,2
,6,6-tetramethyl-4-piperidyl)imino]]
Or a mixture of two or more of these is preferred. In addition, as phosphorus antioxidants, distearyl pentaerythritol diphosphite, tetrakis (2,4-di-t
-butylphenyl)-4,4'biphenylene-diphosphonite, bis(2,4-di-t-butylphenyl)-pentaerythritol-siphosphite, bis(
2,6-di-butyl-4-methylphenyl)-pentaerythritol-diphosphite, bis(2,6-
di-t-butyl-4-n-octadecyloxylponyledylphenyl)-pentaerythritol-diphosphite, tris(2,4-di-L-butylphenyl)phosphite and mixtures of two or more thereof. I can give an example. The blending ratio of the compound A is 1 part ethylene polymer
0.05 to 5 parts by weight, preferably 0.00 parts by weight
．． 1 to I heavy fit part. If the amount is less than 0.05 parts by weight, the thermal stability of the crosslinked ethylene polymer in practical use will be unstable. Not only is it impractical as no improvement in stability can be expected, but it is also uneconomical. The blending ratio of the phosphorus antioxidant is 0.01-1 parts by weight, preferably o, os to o, to 111 parts of the ethylene polymer +00.
5! nit club teal. If the amount is less than 0.01 part by weight, thermal oxidative deterioration during melt-kneading of the crosslinked ethylene polymer can be prevented.
The effect is not fully demonstrated, and it is one more thing! Although it is acceptable to exceed 1 part, it is not only impractical but also uneconomical since no improvement in the effect of preventing thermal oxidative deterioration of 1 ton can be expected.

For the radical generator used in the present invention, in order to obtain a uniform composition, it is preferable that the decomposition temperature is not too low, and the temperature to obtain a half-life of 10 hours is 70°C or higher1], preferably 100°C. Z-) benzoyl peroxide, di-butyl perbenzoate, L-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2,5-di-medyl-2,5-di-(benzoyl perbenzoate) oxo)hexane, 2,5-nomethyl-2
,5-di-(benzoylperoxy)hexyne-3,t
-Butyl-di-baradivate, L-butyl peroxy-3,5,5-trimethylhexanoate, medyl-ethyl ketone peroxide, Tsuku [1 hexanone peroxide, no-L-butyl peroxide, Milbar oxide, 2,5-di-methyl-2,5-no (
2-butylperoxy)hexane, 2,5-di-methyl-2,5-di-(butylperoxo)hexane-3
,! , 3-bis-(L-butylperoxyisopropyl)benzene, t-butylcumyl peroxide, 1.
1-bis-(butylperoxy)-3,3,5-trimethylcyclohexanone, 1.1-bis-(1-butylperoxy)cyclohexane, 2.2-bis-=(L
-butylperoxy)butane, p-menthane hydroperoxide, di-isopropylbenzene hydroperoxide, cumenehyde [1 peroxide, di-
Butyl hydroperoxide, p-cymene hydroperoxide, 1,1.3.3-tetramethylbutylhyde [l peroxide or 2,5-di-methyl-2,5-no (hydroveroquine) Examples include white organic peroxides such as hexane. In particular 2,5-di-methyl-2,5-no(t-butylperoxy)hexane, 2,5-di-methyl-2,5-di-(t-butylperoxy)hexane-3 or 1. 3-bis-(L-butylperoxyisopropyl)benzene is preferred. The mixing ratio of the radical generator is usually 10 parts of the ethylene polymer.
The amount is 0.001 to 0.5 ton and 111 parts, preferably 0.01 to 0.2 ton, based on 0 parts by weight.

The melt-kneading process may be carried out at temperatures of 150°C to 300°C, preferably 180°C to 270°C, using various melt-kneading apparatuses described below.
Perform at a temperature of °C. If the melt-kneading treatment temperature is less than 150°C, sufficient crosslinking will not take place, and if it exceeds 300°C, thermal oxidative deterioration of the ethylene polymer will be accelerated and the coloration of the ethylene polymer will become noticeable, which is not preferred.

In the production method of the present invention, the titanium content of the catalyst residue used is 5 ppm or more, or the titanium content is 0.5 ppm or more.
Various additives that are usually added to ethylene-based composites, such as thioether antioxidants, light stabilizers, clarifying agents, nucleating agents, lubricants, antistatic agents, and antifogging agents, are added to ethylene polymers containing ppm or more. , undeblocking agents, dropless agents, pigments, heavy metal leather activators (copper damage inhibitors), dispersants or neutralizing agents for metal soaps, inorganic fillers (e.g. talc, mica, clay, wollastonite, Zeolite, asbestos, calcium carbonate, aluminum hydroxide, magnesium hydroxide, silicon dioxide, titane dioxide, zinc oxide,
Magnesium oxide, zinc sulfide, barium sulfate, calcium silicate, glass fiber, carbon fiber, potassium titanate,
The inorganic filled paper, synthetic fibers, natural fibers, etc. that have been surface-treated with a surface treatment agent such as metal fibers, etc.) or coupling agents (for example, butane-based, titanate-based, boron-based, aluminate-based, zircoaluminate-based, etc.) ) can be used in combination within a range that does not impair the objective of the present invention.

In the production method of the present invention, the titanium content of the catalyst residue is reduced to 5 ppm.
J containing vanadium of 0,5 ppm or more, the above-mentioned compound Δ to the ethylene polymer, a phosphorus antioxidant, a radical generator, and various types of 1jq that are usually added to the ethylene polymer. A predetermined amount of the additive is mixed using a conventional mixing device such as Hensel Mixer (trade name), Super Mixer, Ribbon Blender, Pan Bali Mixer, etc. at a temperature that does not decompose the blended radical generator. +'p-screw extruder, twin-screw extruder, Brabender or [1-ru, etc., at a melt-kneading temperature of 1
This is carried out by melt-kneading at 50°C to 300°C, preferably 180°C to 270°C.

1 effect" In the present invention, compound A is described in Plastics, Vol. 35, 1.
No. 1, 44-580 (1984 edition), and aims to improve thermal stability (heat resistance) during practical use. Phosphorous oxidation amount 1
The arsenic is used as a peroxide decomposition agent to prevent thermal oxidative deterioration during melt-kneading, and the radical generator generates radicals during melt-kneading treatment, that is, heating, and extracts hydrogen atoms from ethylene polymers. It is well known that it generates coalescence radicals, crosslinks ethylene polymers, and improves mechanical strength, heat-resistant rigidity, etc.

In the production method of the present invention, the compound mentioned above does not become colored because the compound Δ does not produce color-forming atomic groups such as quinone compounds, which are seen in the antioxidant 11 process of phenolic antioxidants. Conceivable.

[Effect Prefecture 1] The crosslinked ethylene polymer obtained by the production method of the present invention is disclosed in the above-mentioned Japanese Patent Application No. 1555/1989 filed by the present inventors.
Compared to the crosslinked ethylene polymer related to No. 99, there is no coloration and mechanical strength and heat resistance rigidity are improved, so it can be used for injection molding, extrusion molding (especially electric wire coating, foaming), b[l-molding] It can be suitably used to produce molded articles of interest by various molding methods such as.

[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: YT (Yellow
+essIndex) was measured (based on JIS K 7103), and the colorability was evaluated based on the magnitude of this Yl value.

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

Examples 1-16, Comparative Examples 1-3 As the ethylene polymer, Ml (discharge amount of molten resin in 10 minutes when applying a load of 2.16 kg at 190°C) was stabilized at 1.59/10 minutes. Tetrakis (2,2,6,6-tetramethyl-
4-piperinor) 1,2,3,4-butanetetracarboxylate, 3,9-bis[1,1-dimethyl-2-(
tris(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)butylcarbonylokino)ethyl]-2,4,8,10-tetraoxaspiro[5,
5] Undecane, poly[[6-1': (1,1,3,
3-tetramethylbutyl)amino]-], 3.5-
triazine-2,4-diyl][(22,6.6-tetramethyl-4-piperidyl)iminocohexamethylene[
(2,2,6,6-tetramethyl-4-piperidyl)imino]] or poly[[6-morpholino-1,3,
5-triazine-2,4-diyl] [(2,2,6,
6-tetramethyl-4-piperidyl)imino]hexamedylene [(2,2,6,6-tetramethyl-4-piperidyl)imino], bis(2,
4-di-t-butylphenyl)-pentaerythritol-diphosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite or tris(2,4-diphosphite) -butylphenyl) phosphite, 2,5-di-methyl-2,5-di-(t-butylperoxy)hexane or 1,3-bis-(t-butylperoxy) phosphite [J (pill) Benzene and other additives were added to a Hensel mixer (trade name) at the mixing ratios listed in Table 1 below, mixed for 3 minutes, and then mixed using a single screw extruder with a diameter of 40M11. The mixture was melt-kneaded at 200°C to crosslink and form pellets. In addition, as Comparative Examples I to 3, 100 parts by weight of a powdered Ziegler-Natsuta ethylene polymer (titanium content: 8 ppm) with an Ml of 1.5 y/10 min, Predetermined additives were blended and melt-kneaded according to Examples 1 to 16 to obtain crosslinked pellets.

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

Examples 17-32, Comparative Examples 4-6 As ethylene polymer, M I 0.591 I 0
unstabilized powdered Ziegler-Natsuta high-density ethylene-propylene copolymer (30 methyl branches/
1000 carbon, titanium content 8 ppm), tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3.4-butanetetracarboxylate, 3.9- bis[l,1~trimethyl-2-(tris(+,2.2,6.6~pentamethyl-
4-Biberinoloxycarponyl)butylcarbonyloxy)ethyl-]-2,4,8,IO-tetraoxaspiro-C5,5]undecane, poly[[6-[(1
,1,3,3-tetramethylbutyl)amino]-1,3
,5-triazine-2,4-diyl E [(2,2,6
,6-titramedylene-4-piperidyl)imino]hexamethylene[(22,6.6-tetramethyl-4-piperidyl)imino]" or poly[[6-morpholino-
1,3.5-triazine-2,4-diyl]'(2,2
,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-
piperidyl)imino]], bis(2,4-1-t-butylphenyl)-bentaerythritolnow A-sphite, tetrakis(2,4-di-1-butylphenyl)-4, 4'-biphenylene-nophosphonite or tris(2,4-di-t-
--/tylphenyl) phosphite, 2.5-nomethyl-2゜5-no(t-butylperoxy)hexane or 1.3-bis-(L-butylperoxyisopropyl)benzene as a radical generator, and others. A predetermined amount of each of the additives was added to a Hensel mixer (trade name) at the mixing ratio shown in Table 2 below, and after stirring and mixing for 3 minutes, the mixture was melt-kneaded at 200°C using a single-screw extruder with a diameter of 40xz. It was then crosslinked and made into a pellet. Also, Comparative Example 4~
6 as M [0.5 g/10 min. A predetermined amount of each of the additives listed in Table 2 below was blended with O0 weight part, and Examples 17 to 3 were prepared.
A crosslinked pellet was obtained by melt-kneading according to 2.

The obtained pellets were used to evaluate the colorability according to the test method described above. The results are shown in Table 2.

Examples 33 to 48, Comparative Examples 7 to 9 As the ethylene polymer, an unstabilized powdered Ziegler-Natsuta-based high-density ethylene-butene-1 copolymer (ethyl branched 0 .014 pieces/+000 carbon, vanadium containing t7t0.6ppm)
To 100 parts by weight, tetrakis (2,2
,6,6-tetramethyl-4-piperidyl)1,2,3
．． 4-butante) lacarboxylate, 3,9-bis[1,1-dimethyl-2-(1-lis(1,2,2,6
,6-bentamedyl-4-piperidyloxycarbonyl)butylcarbonyloxy)ethyl]-2゜4.8.1
0-tetraoxaspiro[5,5]undecane, polyr
[G-[(+,1,3.3-tetramethylbutyl)amino]-1.3.5-1-riazine-2,4-diylco
"(2,2,6,6-tetramethyl-4-piperidyl)
imino J hexamethylene r (2,2,6,6-tetramethyl-4-piperidyl) imino J ] □L< is poly[1G-morpholino-1,3,5-triazine-2°4-diyl] [( 2,2,6,6-tetramethyl-
4-piperidyl)imino]hexamethylene [(2,2,
6,6-tetramethyl-4-piperinor)imino]1,
Phosphorous antioxidants include bis(2,6-di-L-butyl-4-methylphenyl)-bentaerythritol, tetrakis(2,4-di-t-butylphenyl)-4, 4'-biphenylene diphosphonite or tris(2,4-di-monobutylphenyl) phosphite, 2.5 as a radical generator
-di-methyl-2,5-di-(1°-butylperoxy)hexane or 1,3-bis-(1-butylperoxyisopropyl)benzene and other additives, respectively, as specified in 1 below. The mixture ratios listed in Table 3 were put into a Hensel mixer (trade name), stirred and mixed for 3 minutes, and then melted and kneaded at 200°C in a single-screw extruder with an L1 diameter of 40zx to crosslink and form a beret). did. Also, Comparative Examples 7 to 9
Unstabilized powdered Ziegler-Natsuta high-density ethylene-butene-I copolymer (ethyl branched Q, 4 OI/+000 carbon, vanadium containing (1"+tO, 6ppm) with Ml of 1.09/10 minutes ) A predetermined amount of each of the additives listed in Table 3 below is blended with 100 parts by weight,
Crosslinked pellets were obtained by melt-kneading according to Examples 33-48.

Using the obtained pellets, colorability was evaluated according to the test method described above. The results are shown in Table 3.

Examples 49 to 64, Comparative Examples 1O to 12 Mooney viscosity M11+4 (1
00°C) 25 unstabilized powdered amorphous ethylene-propylene copolymer (propylene content 1-25%)
, vanadium-containing (i'+ko, 6ppm) IOQ weight tl
Tetrakis (2,2,6,6-
1,2,3,4-butanetetracarboxylate, 3,9-bis-[1,1-
Dimethyl-2-(tris(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)butylcarbonyloxy)ethyl]-2,,4,8,10-tetraoxaspiro[5,5]undecane , poly[[6-[
(+,1,3.3-tetramethylbutyl)aminoco-1
,3,5-triazine-2,4-diyl][(2,2,
6,6-titramedylene-4-piperidyl)imino]hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl)imino]] or poly[[6-morpholino-1,3,5-triazine-2 ,4-diyl] [
(2,2,6゜6-tetramethyl-4-piperidyl)imino]hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl)iminococo, bis(2,6 -not-t-butyl-4-methylphenyl)-pentaerythritol-diphosphite, tetrakis(2,4-not-butylphinyl)-i4'
- biphenylene-nophosphonite or tris(2,4-di-butylphenyl)phosphite,
As a radical generator, 2,5-nomethyl-2,5-no (L-butylperoxy)hexane is 1.3
-bis-(L-butylbaroquinoisobrobyl)benzene and other additives, respectively, in the fourth step described below.
Add the blending ratio listed in the table to a Hensel mixer (trade name) and stir and mix for 3 minutes.
The mixture was melt-kneaded using a screw extruder at 200°C to crosslink and form pellets. In addition, unstabilized powdery amorphous ethylene-propylene copolymer with a Mooney viscosity ML1+4 (100°C) of 25 (propylene content 25%, vanadium-containing (T, l' it 0
, 6 ppm) 1 part of IOO, iR, and ji were blended with predetermined t1 of each of the additives listed in Table 4 below, and melt-kneaded according to Examples 49 to 64 to obtain crosslinked pellets. .

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

The various compounds and additives shown in Tables 1 to 4 are as follows. .

Compound A[I]; Tetrakis(2,2,6,6-te1ramethyl-4-piperidyl)1.2.3.4-butanetetracarboxylate Compound Ar1T]: 3.9-bis[1,1 -dimethyl-
2-(tris(+, 2.2.6.6-pentamethyl-4
-piperidyloxycarbonyl)butylcarbonyloxy)ethyl]-2,4゜8,lO-tetraoxaspiro[5,5J undecane compound [:III]; poly[16,-[(1,I,3
．． 3-tetramethylbutyl)aminoco-1,3,5-1
-rianone-2,4-diylco r (2,2,6,6
-tetramethyl-4-piperinor)imino 1 hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl)imino 1" Compound A[]'/F+poly[[6-morpholino-1,
3,5-triazine-2,4-noyl [(22,
6.6-Tetramethyl-4-piperidyl)imino]hexamedylene [(2,2,6,6-tetramethyl-4-piperidyl)iminocholine antioxidant [1], bis(2
,4-di-butylphenyl)-pentaerythritol-diphosphite phosphorus antioxidant cr; Tetrakis(2,4-di-
t-Butylphenyl L-4,4'-biphenylene-di-
Phosphonite phosphorus antioxidant [ITN Nidris (2,4-di-butylphenyl) Phosphite phosphorus antioxidant [■]; Bis(2,6-di-t-butyl-4-methylphenyl) )-Pentaerythritol-diphosphite radical generator [1]; 2,5-di-methyl-2゜5-
Di-(t-butylperoxy)hexane radical generation I
l'FllC111; 1,3-his-(thiobylperoquine isobubil)benzene phenolic antioxidant 1.2,6-di-butyl-p-cresol phenolic antioxidant 2: Tetrakis[methylene -3
-(3',5'-di-butyl-4'-hydroquinphenyl)buCj pionate comethane polyol compound (iTB ester of polyol and fatty acid), pentaerythritol monostearate + 1ALS (with phenolic hydroxyl group) +-[2-43-(3,s-di-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4,-[3-(3,5-no[-butyl- 4-hydroxyphenyl)propionyloxy]-2
, 2,6,6-titramethylbiperidine Ca-5t; Calcium stearate The examples and comparative examples listed in Table 1 are cases where a Ziegler-Natsuta-based high-density ethylene homopolymer is used as the ethylene-based polymer. It is. As can be seen from Table 1, in Examples 1 to 16, the titanium content of the catalyst residue according to the present invention was 8 p.
Compound A, a phosphorus-based antioxidant, and a radical generator are blended into an ethylene homopolymer containing PM, and the mixture is melt-kneaded and crosslinked. Examples 1 to 16 and Comparative Example 1 (
Patent application No. 61, -155599 previously proposed by the present inventors
A method for producing a crosslinked ethylene polymer for the party appetizer, namely, blending an ethylene polymer with a partial ester of a polyol and a fatty acid, a phenolic antioxidant, and a radical generator.
Example 1
It can be seen that Samples 1 to 16 were less colored than Comparative Example 1, and the coloring and city resistance was improved. Comparing Example 1-16 with Comparative Example 2 in which a hindered amine compound having a phenolic hydroxyl group was used in place of Compound A, Comparative Example 2 was markedly colored, and this coloring was due to the phenol of the hindered amine compound listed above. It can be seen that this is due to the formation of a quinone compound by the hydroxyl group. Furthermore, when comparing Examples 1 to 16 with Comparative Example 3, in which the partial ester of polyol and fatty acid used in Comparative Example 1 was further added to Comparative Example 2, it was found that Comparative Example 3 was similar to Comparative Example I, although the colorability was improved. Example 1~
It can be seen that it is not as high as 16.

Tables 2 to 4 show, as ethylene polymers, Degla-Natsuta high-density ethylene-propylene copolymer, Ziegler-Natsuta high-density ethylene-butene-l copolymer, and non-grade ethylene polymer [1]. A pyrene copolymer was used, and the same effects as described above were confirmed with these 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.

From this, the crosslinked ethylene polymer obtained by the production method of the present invention is obtained by blending a conventionally known compound with a discoloration prevention effect and melt-kneading it in the presence of a radical promoter to crosslink it. It was found that the anti-coloration property was significantly better than that of the original, confirming the remarkable effect of the present invention.

that's all

Claims (5)

[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, 0.05 to 5 parts by weight of a hindered amine compound having no phenolic hydroxyl group (hereinafter referred to as compound A), and 0.01 to 1 part by weight of a phosphorus antioxidant.
1. A method for producing a crosslinked ethylene polymer, comprising blending 0.001 to 0.5 parts by weight of a radical generator and melt-kneading the mixture at 150°C to 300°C. (2) As compound A, tetrakis (2,2,6,6-
tetramethyl-4-piperidyl) 1,2,34-butanetetracarboxylate, 3,9-bis[1,1-dimethyl-2-{tris(1,22,6,6-pentamethyl-4-piperidyloxycarbonyl) ) butylcarbonyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, poly[[6-[(1,1,
3,3-tetramethylbutyl)amino]-1,3,5-
triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)
imino]], poly[[6-morpholino-1,3,5-
triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)
The method for producing a crosslinked ethylene polymer according to claim (1), wherein a mixture of two or more of these is blended. (3) As a phosphorus antioxidant, bis(2,4-di-t
-butylphenyl)-pentaerythritol-diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)-pentaerythritol-diphosphite, tetrakis(2,4-di-t-butylphenyl) -4
, 4-biphenylene-di-phosphonite, tris(
2,4-di-t-butylphenyl) phosphite or a mixture of two or more thereof is blended in the method for producing a crosslinked ethylene polymer according to claim (1). (4) As a radical generator, 2,5-di-methyl-2
, 5-di-(t-butylperoxy)hexane, 2,5
-di-methyl-2,5-di-(t-butylperoxy)
The method for producing a crosslinked ethylene polymer according to claim (1), which comprises blending hexyne-3 or 1,3-bis-(t-butylperoxyisopropyl)benzene. (5) As the ethylene polymer, ethylene homopolymer,
Amorphous ethylene-propylene copolymer, crystalline ethylene-butene-1 copolymer, crystalline ethylene-propylene-butene-1 ternary copolymer, containing ethylene as the main component;
A crosslinked ethylene polymer according to claim (1), which uses a crystalline ethylene-pentene-1 copolymer, a crystalline ethylene-hexene-1 copolymer, or a mixture of two or more thereof. Production method.