JPS6042441A - Polyethylene composition - Google Patents

Abstract

PURPOSE:To provide a carbon black-contg. polyethylene having improved heat resistance, by blending carbon black, a kindered phenol, a thiodipropionate ester compd. and a hindered amine compd. with polyethylene. CONSTITUTION:Carbon black, a hindered phenol compd. whose skeleton is composed of isocyanuric acid, a thiodipropionate ester or pentaerythritol tetrakis (beta-alkylthiopropionate)ester (wherein alkyl groups have 10-20 carbon atoms and may be the same or different groups) and a hindered amine compd. are blended with polyethylene. Examples of polyethylene are ethylene homopolymer and copolymers. Pref. said copolymers have an ethylene content of at least 50wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene composition containing carbon black and having excellent heat resistance and weather resistance.

Conventionally, carbon black has been blended into polyethylene for various purposes. These are mainly used as pigments or fillers used to improve ultraviolet ray deterioration and thermal oxidative deterioration of polyethylene. However, thermal oxidative deterioration cannot be significantly improved unless carbon black and further stabilizers are added, such as thiobisphenol compounds, hindered phenol compounds, sulfur compounds, or hindered phenol compounds. It is used in combination with sulfur-based compounds and sulfur-based compounds.

However, although the improvement effect of carbon black and these stabilizers alone or in combination has been observed,
It was not always sufficient in terms of long-term heat oxidation deterioration resistance.

The present invention was made for the purpose of further improving the heat resistance of conventionally known polyethylene containing carbon black, and the polyethylene composition of the present invention comprises polyethylene containing (a) carbon black, (b) Hindered phenol compound with isocyanuric acid as a skeleton (C)
Thiodipropionic acid ester compound or pentaerythritol-tetrakis (β-1 alkylthiobrobionic acid ester) (however, alkyl has 10 to 20 carbon atoms and may be the same or different) and ( d) a hindered amine compound.

The polyethylene used in the present invention is an ethylene homopolymer or ethylene copolymer that can be produced by a high-pressure method or a low-pressure method, such as ethylene and propylene, 1-butene, 1-pentene, 1-heptene, 1-octene, α having 3 to 20 carbon atoms such as decene, 4-methyl-1-pentene, etc.
-Copolymers with olefins, vinyl acetate, acrylic esters, etc. can be mentioned. Ethylene copolymer is
Although two or more types of comonomers may be used, it is preferable that the ethylene content is 50% by weight or more. The density of these polyethylenes is at least [L 85 f/
cc or more, preferably α90 to α979/cc, but it may be larger if it can be molded. In addition, melt index (temperature 19 according to JIS K 6760)
Measured under the conditions of 0S load 2.16 and 9, hereinafter referred to as MI)
is 0.05 to 50 f/10 min, preferably 11 to 10
It is 9/10 minutes. These polyethylenes may be used alone or in a mixture, and other olefin elastomers such as ethylene-propylene rubber, ethylene-1-butene rubber, butyl rubber, polyisobutylene rubber, butadiene rubber, styrene-butadiene rubber,
Ethylene-propylene-dieneta polymer, etc. may be mixed. Among the above polyethylenes, high density polyethylene, low density polyethylene, linear low density polyethylene and the like are preferred.

Any type of carbon black may be used in the present invention, such as channel black,
Furnace black, 1 seteren black, etc. can be increased. Further, it can be used whether it is conductive or non-conductive. The average particle diameter of carbon black is preferably 1000A or less, preferably 550A or less, in order to improve dispersibility in the composition.

Among these, Farne Subrac is preferred.

Examples of the Lardphenol compound (hereinafter referred to as compound (I)) having isocyanurate as its core used in the present invention include tris(3,5-di-t-butyl-4-hydroxy benzyl) isocyanurate, tris[β-(5,5-di-butyl-4-hydroxyphenyl)propionyl-oxyethyl]isocyanurate, 1,5.5-tris(4-1lkyl-5-hydroxy-26-dimethyl) benzyl) isocyanurate (wherein the alkyl is a branched 11-lekyl group of Cs''-Cx*), etc. Among these, 1.3.
5-Tris(4-1-butyl-6-hydroxy-2,
6-dimethylbenzyluneate is preferred.

The esters of thiodipropionic acid (hereinafter referred to as compounds) used in the present invention include dilaurylthiodipropionate, dilaurylthiodipropionate, dimyrist! Rethiodipropionate, lauryl steari! Rethiodiprobionate, dibutyltheodipropionate, dinonylthiodipropionate, diheptylthiodipropionate, diocti J rethiodipropionate, dinonylthiodipropionate, didecylthiodipropionate, dipentadecyl Examples include theodiprobionate, dicetylthiodipropionate, diheptadecyltheopropionate, etc. In addition, as pentaerythritol-tetrakis (β-1-rukylpropionatene (hereinafter referred to as compound (III)), 1-rukyl is an 11-rekyl group with 10 to 20 carbon atoms, and those that are the same or different from each other are can give.

Among these compounds (II) and (III), pentaerythritol-tetrakis (β-lauryl propionate) is preferred.

The hindered amine compound (hereinafter referred to as compound (iv)) used in the present invention preferably has a high molecular weight, such as bis(2,2,6.6-tetramethyl-4-piperidyl) sebacate, 4-benzoyl Oxy-2,2,6,6-tetramethylbiperidine, succinic acid and N-(2-hydroxyethyl)-2,2,6,6-
condensate with tetramethyl-41 hydroxypiperidine,
1.2,5.4-tetra(2,2,6,6tetramethyl-4-piperidyl)-butanetetracarboxylate,
1,4-di(2,2,6,6-tetramethyl-4-piperidyl)-293-butanedione, Pol C(6-(1
,1,5゜6-tetramethylbutyl)imino] -1,
3,5-triazine-2,4-diyl](,4-(2,
2,6,6-tetramethylpiperidyl)imino]hexamethylene-(4-(2,2,6,6-tetramethylpiperidyl)imino), bis(1,2,2,6,6-bentamethyl-4-piperidyl) ) Separate, G (2, 2,
6,6-tetramethyl-4-piperidyl and 1-(5,
5-di-t-butyl-4-hydroxyphenyl-methyl)-1,1-pentanedicarboxylate, bisC1
,2,6,6-bentamethyl-4-piperidyl)-2-
Normal-butyl-2-(3,5-di-t-butyl-4
-hydroxybenzyl) malonate, 1,6-bis(2
,2,6,6-tetramethyl-4-piperidylamino)
Hexane and 2,4-di-halo loaf morpholino-i
, condensate with 6,5-triazine, poly[6-morpholino-1,3,5-triazine-2,4-diyl][4-
(2,2,6,6-titramethylbiperidyl]imino]
6, such as hexamethylene-(4-(2,2,6,6-tetramethylpiperidyl)imino). Among these, poly[('!l = (1111313-tetramethylbutyl)imino]-1, 3,5-triazine-3
,4-diyl) [4-(2,2,6,6-tetramethylpiperidyl)imino]hexamethylene-(4-(2,
2,6,6-tetramethylpiperidyl)imino], succinic acid and N-(2-hydroxyethyl)-2,2,6,
A condensate with 6-tetramethyl-4-hydroxypiperidine is preferred.

The above carbon black and stabilizer (I) or ■
) is added to polyethylene in an amount of 10
．． Carbon black is 0.1 to 0.1 to part Oli.
10 parts by weight, preferably 0.2 to 5 parts by weight, of compound (I
) is 0.01 to 1.0 parts by weight, preferably 0.02 to 0
．． 6 parts by weight, compound (II) and/or (ill)
is from 0.01 to parts by weight, preferably from 0.02 to 0.6 parts by weight.
parts by weight and the compound (TV) is from 0.01 to 2.0 parts by weight, preferably from 0.02 to 1.0 parts by weight. If the amount of carbon black is less than 0.1 parts by weight, there is no improvement in heat resistance and ultraviolet light shielding, and if it exceeds 10% by weight, the mechanical strength of the polyethylene will be lost and it is also economically unfavorable.

Further, if the amount of the stabilizer added is less than 0.01 part by weight, there is no improvement effect on thermal oxidative deterioration, and if it exceeds the upper limit, a plate-out phenomenon occurs, which is not preferable.

Although compounds containing stabilizer compounds (1) to (■) in addition to carbon black exhibit sufficient heat-oxidation resistance, they also contain an organic phosphite compound (hereinafter referred to as compound (V)) per 100 parts by weight of polyethylene. or an organic phosphonite compound (hereinafter referred to as compound (vi)) o,
By adding o i to tO parts by weight, preferably α02 to 0.3 parts by weight, thermal stability during processing (pelletization) is further increased and molding processability is improved. however,
It is not preferable that the zero-loading lid exceeds 1.0 part by weight because it causes a plate-out phenomenon.

The above compound (V) is, for example, 4,4'-buteridine-bis(6-methyl-6-t-butylphenyl-
di-tridecyl) phosphite, 1.1.3-tris(2-methyl-4-di-tridecyl) phosphite-5
-t-butylphenyl butane, distearyl pentaerythritol diphosphite, trisnonylphenyl phosphite, bis(2,4-di-t-butylphenyl)
Pentaerythritol diphosphite, tris(2,4
-di-t-butylphenyl) phosphite and the like. Further, as the compound (Vl), for example, tetrakis(2,4-di-t-butylphenyl)4,4'-biphenylene diphosphonite can be mentioned. These compounds (
Among V) and (vi), tris(2,4-di-
t-butylphenyl) phosphite, tetrakis(2,
4-di-t-butylphenyl) 4.4'-biphenylene diphosphonite and the like are preferred.

Any known method can be used to uniformly mix the above-mentioned carbo black and stabilizer compound into polyethylene. Examples include a method in which each component is premixed using a ribbon blender, Henschel mixer, etc., and then pelletized using an extruder, or a method is melt-mixed using a Banbury mixer, kneader, etc., and then pelletized using an extruder. It will be done. In this case, in order to mix carbon black uniformly, a masterbatch is prepared by blending carbon black with a polyethylene dispersion medium at a high concentration, as is often done in the past when blending sunset scenery components, and this is mixed in a predetermined amount. It is convenient to blend it into polyethylene so that d[.

In addition to the above-mentioned compounds, the polyethylene composition may further contain ultraviolet absorbers, neutralizers, pigments, fillers, lubricants, surfactants, nucleating agents, and the like, if necessary.

As described above, the composition of the present invention can be molded into various shapes by commonly used molding methods such as extrusion molding, blow molding, press molding, and injection molding. In addition, this composition has excellent heat resistance and weather resistance, and does not cause the plate-out phenomenon, so it is suitable for applications used in particularly harsh environments, such as steel pipe coatings, solar water heater heat collectors, and automobile interiors and exteriors. It is suitable as a material for products, pallets, etc.

The present invention will be explained in more detail below using Examples. The trial sales method t1 in the example is as follows.

(1) Tensile strength, tensile elongation ASTM D<538, measured at a tensile rate of 50/min.

(2) Heat Resistance Test After 200 hours of ultraviolet irradiation with a sunshine weather meter (66°C), after heating in an air constant temperature bath at 126°C, tensile strength and tensile elongation were measured, with the initial value before heating being 100. It was expressed as the retention rate.

(3) Plate-out property After heat resistance test (after 20 days), no stabilizer is observed on the surface of the test piece: ◎, and very little stabilizer is observed: ○
, those with a small amount of plate-out were designated as ×, and those with a large amount of plate-out were designated as XX.

Example High density polyethylene (MI=0.2F/10min, density=
IJ, 955 r/cc, hereinafter referred to as HDPE) 1
ooMfA part was blended with 3 parts of stabilizer and neutralizer (calcium stearate) in the proportions shown in Table 1, premixed in a Henschel mixer, and then melted in an extruder at 200'C. The mixture was kneaded and pelletized.

Carbon black masterbatch (HDPE'75) containing this pellet trap furnace black type carbon black (Cabot M VULCAN 9i2)
HD
Carbon black was premixed in an amount of 2 parts by weight with respect to 100 parts by weight of PE, and the mixture was mixed at t-2oo<0>C to pelletize the composition.

The pellets obtained here were put into a press molding machine at 120°C.
A dumbbell-shaped test piece (No. 2 dumbbell) was completely molded. Using this test piece, the tensile strength and tensile strength before and after the heat resistance test, the tensile elongation, and the plateout of the stabilizer after the heat resistance test were evaluated, and the results are shown in Table 1.

For comparison, test pieces were similarly molded and evaluated for those that did not use the stabilizer combination of the present invention.
The results are also listed in Table-1.

Compound (I) Al; 1,3.5-1-lis(4-t-butyl-3-
Hydroxy-2,6-dimethylbenzyl)isocyanurate A2; tris(6,5-di-t-butyl-4-hydroxybenzylene isocyanurate compounds (11) and (111,) B,; distearyl theodibro Pionate B2; pentaerythritol tetrakis (β-lauryl-propionate compound (ff) UV, ; bix (2,2,6,6-f tramethyl-4
-piperidyl) sebacate U, V; succinic acid and N-(2-hydroxyethyl)
-Condensate with 2,2,6,6tetramethyl-4-hydroxypiperidine [Jv, ; poly((6-(L1t3t'-tetramethylbutyl)imino)-1,3,5-triazine-2,
4-diyl) (4-(2+2t't6-titramethylpiperidyl)imino]hexamethylene-[4-(2,2
,6,6-titramethylpiperidyl)imino] Compounds (V) and (VI) Pl; Tetrakis(2,4-di-t-butylphenyl)
4.4'-biphenylene diphosphonite P! ; tris(2,4-di-t-butylphenyl)phosphite thiobisphenol compound C,; 4,4' thiobis(6-mether-6-t-butylphenol) C2; tetrakis[methylene-5-(3', 5'-G-
t-Butyl-4'-hydroxyphenyl)-propionate] methane agent 1) Akira agent Ryo Hagihara -

Claims (1)

[Claims] To polyethylene, (a) carbon black, (b) a hindered phenol compound having an isocyanuric acid skeleton, (C) a thiodipropionic acid ester compound or pentaerythritol-tetrakis (β-alkylthiopropion ester) (however, Alkyl has 10 to 2 carbon atoms
0 and may be the same or different) and (
d) A polyethylene composition blended with a hindered amine compound.