JPS60106846A - Polyethylene composition - Google Patents

Abstract

PURPOSE:A composition having excellent nerve and transparency and suitable as a film, comprising a specified combination of polyethylene, a copolymer of ethylene with an alpha-olefin or vinyl acetate, an ionomer, and Mg or Ca salt of a sulfonic acid. CONSTITUTION:A polyethylene composition comprising 70-95pts.wt. polyethylene or ethylene-alpha-olefin copolymer ( I ) having the following properties a density of 0.94g/cm<3> or higher, a melt flow index by ASTM-D-1238E of 1g/10min or lower, and a ratio of the melt flow index by ASTM-D-1238E to that by ASTM-D-1238F of 40 or smaller, 5-30pts.wt. one or more of a high-pressure low-density polyethylene, an ethylene-vinyl acetate copolymer, an ionomer, and an ethylene-alpha-olefin copolymer having a density of 0.935g/cm<3> or lower (II) ( I +II=100pts.wt.), and 0.01-5pts.wt. one or more of Mg and Ca salts of an alkylsulfonic acid and those of an alkylbenzenesulfonic acid (III).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene composition suitable for use in films that are strong and have excellent transparency.

Among polyethylenes, high-density polyethylene has a high degree of crystallinity, so a film with high rigidity and stiffness can be obtained, but its transparency is poor and its use as a packaged product is limited. On the other hand, low-density polyethylene has a lower crystallinity than high-density polyethylene, so it has excellent transparency, but it lacks rigidity and is difficult to make thin when molded into a film. In recent years, the wave of resource and energy conservation has been reflected in the packaging industry, and strong, thin films with excellent transparency are now being used for packaging.

This demand is particularly high for polyethylene, which has a large impact on film applications, and resin manufacturers are conducting research to meet this demand.

However, as mentioned above, both high-density polyethylene and low-density polyethylene have their own problems, and it is difficult to provide polyethylene having the properties that are highly desired.

The present invention provides a type of polyethylene that satisfies such needs, and particularly relates to a polyethylene suitable for the field of air-cooled blown films.

That is, the present invention provides (1) the following +A1~? Ethylene polymer or ethylene/α-olefin polymer having a+ properties 70 to 9
5 parts by weight, (B) Melt flow index based on the measurement method of ASTM D 1238 is Ig 710 min or less, (
0) Melt flow index based on ASTM D 1258H measurement method and ASTM D 1'21F'
Ratio HL of melt flow index based on the measurement method of
M-work/M-work is 40 or less, (It) 5 to 30 parts by weight of at least one selected from the group consisting of low density polyethylene, ethylene/vinyl acetate copolymer, ionomer, and ethylene/α-olefin copolymer. (However, 1 Togawa is 100 parts by weight.) (1) 0.01 to 5 parts of at least one magnesium salt or calcium salt of a sulfonic acid selected from alkyl sulfonic acids and alkylbenzene sulfonic acids; Accordingly, there is provided a polyethylene composition comprising 0.05 to 0.5 parts by weight of at least one selected from dibenzylidene sorbitol or its nuclear substituted product.

The first component of the present invention has a density of 0.94 g/Cm or more, preferably 0.95 g/Cm or more, and a melt flow index (hereinafter abbreviated as M1) of Ig710mi.
n or less, preferably 0.8 g710 min or less, H
Ethylene homopolymer or ethylene and carbon with LM/M of 40 or less, preferably 35 or less and α of 5 to 12
-Olefins, such as propylene, 1-butene, 1-
Copolymers with pentene, 6-methyl-1-'7'tene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene are preferred. Density is ASTM D1
505, measured by the density gradient tube method, M work is AS
TM D12! +8E (temperature 190°C 1 load 2.16
kti), and HLM machining/M machining is A.
STM D 125BF (temperature 190℃, load 21.6
It was determined by comparing the HLM process determined by measurement at kQ) and the above M process.

Ethylene homopolymer or ethylene α outside the above range
- Even if an olefin copolymer is used, a polyethylene composition with excellent rigidity, stiffness, and pulp stability during inflation molding cannot be obtained.

The second component of the present invention compensates for the shortcomings of the first component, such as impact strength and transparency, and is a compound having a lower melting point, better compatibility, and similar refractive index than the first component, Specifically, the density is 0.955g/C1n or less, M work 5. Og
/ High pressure process low density polyethylene for 10 min or less, vinyl acetate content 20% by weight or less, M process 5 g/'10 m
Ethylene-vinyl acetate copolymer, ionomer or density 0.85 to 0.955 g7'CM
.

M-engineer 5. At least one compound selected from copolymers of ethylene of 0g/10'min or less and a small proportion of α-olefin having 6 to 18 carbon atoms can be selected.

Among these, ethylene/α-olefin copolymers are preferred, especially those with a density of 0.85 to C1.91 g/el.
l, M Eng 5. A copolymer of ethylene and α-olefin with a crystallinity of 20% or less by X-rays is preferred, and a copolymer of ethylene and an α-olefin having 6 to 16 carbon atoms is more preferred. The ethylene content is 75 to 95 mol%, the density is 0.85 to 0.91 F, / 10 min, M engineering 4.0
g / 10 min or less, the ratio of the average molecular weight of 11 to several thousand ω molecular weight Mn by the aPO method M W2N n is 4 or less, and the crystallinity by X-ray is 20% or less. Ethylene α-
Olefin copolymers are preferred in this invention. The blending ratio of these above-mentioned polymers is such that the second component is 5.
-50 parts by weight, and the total of the first and second components■
1 to 100 parts by weight.

The sixth component of the present invention is a necessary component for improving molding processability during film molding, producing a film with a smooth surface, and resulting in a film with excellent transparency. Specifically, it is a magnesium salt or calcium salt of a sulfonic acid selected from alkylsulfonic acids and alkylbenzenesulfonic acids. The number of carbon atoms in the alkylsulfonic acid is preferably 8 to 0, particularly preferably 10 to 25, while the number of carbon atoms in the alkyl group of the alkylbenzenesulfonic acid is preferably 4 to 60, particularly 8 to 15. When used in the present invention, these sulfonic acid compounds are used in the form of magnesium salt or calcium salt.

Other metal salt forms, such as lithium salt, sodium salt, and potassium salt, are hygroscopic and may cause foaming during molding, resulting in poor molding. The usage ratio of the sixth component of the present invention is 0.01 to 5 parts by weight based on the total amount [100 parts by weight] of the first component and the second component;
Particularly preferred is 0.05 to 2 parts by weight. Use outside the above range may impair bubble stability during inflation molding, or impair printability, heat sealability, and transparency.

In the present invention, in addition to the above (1) to (1), in order to further improve transparency, dibenzylidene sorbitol or its nuclear substituted product may be added as a fourth component. Dibenzylidene sorbitol may be in the 9-form, L-form or 7-form, and the nuclear substituents of dibenzylidene sorbitol include an alkyl group; for example, a methyl group,
Examples include ethyl group, propyl group, isopropyl group, butyl group, and alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, and derivatives in which the nucleus is substituted with fKt with halogen such as chlorine.

In addition, this nuclear-substituted dibenzylidene sorbitol is
It may be substituted at any of the ortho, meta, or para positions. These dibenzylidene sorbitol or its nuclear substituted product may contain one or more of (1)
+(1) 0.01 to 1 part by weight, particularly 0.05 to 0.5 part by weight per 100 parts by weight.

In order to obtain the polyethylene composition of the present invention, the above-mentioned first to fifth components and, if necessary, dibenzylidene sorbitol or its nuclear substituted product are mixed using a ribbon blender, tumble blender, Henschel mixer, etc., or mixed. Examples include a method of melt-mixing using a post-extruder, a Banbury mixer with 1 and 2 rolls, and the like.

In addition, the composition of the present invention may contain various known additives, such as heat stabilizers, weather stabilizers, antistatic agents, antifogging agents, undeblocking agents, pigments, dyes, and inorganic or organic fillers. etc. may also be blended.

The composition of the present invention obtained in this manner has good rigidity and stiffness, excellent impact resistance and moldability, and good transparency, so that it can be made into a thin film and can be packaged. We can expect development in this field.

The content of the present invention will be explained below using Examples E/TJ.
The present invention is not limited to these examples as long as the purpose thereof is not impaired.

Examples 1 to 10 M engineering 0-45g7100-45g7l0 D 1238
K), density 0.965g/Ci” (ASTM D 1
505'), 90 parts by weight of high-density polyethylene of HLM/M 2B, 10 parts by weight of a polymer not shown in Table 1,
The formulations shown in the table were blended, mixed in Henschel Miki@1-, and then granulated in a 20 mmφ extruder. The obtained pellets were prepared with a grip diameter of 75 m1n and a lip clearance of 1.
A film was formed using a 53 mmφ extruder equipped with a 2 mm inflation die at 200"C and an expansion ratio of 4.0, and the folding diameter was 480 mm and each warp was 20 μ.
Obtained. The physical properties of the obtained film are shown in Table 2.

The physical properties Δ(σ) were determined by the method shown below.

Haze: ASTM D 1003 '5
2 (%) Impact strength: Measured using a film impact tester manufactured by Toyo Seiki Seisakusho at 25°C and an impact ball diameter of 1 inch Young's modulus: Average in the vertical and horizontal directions calculated from the initial slope according to JIS K 6781 Value Comparison Example 1 The same procedure as in Example 1 was carried out except that the magnesium hexadecyl sulfonate of Example 1 was not used.

The results are shown in Table 2.

Comparative Example 2 The same procedure as in Example 1 was conducted except that the ethylene-decene-1 copolymer of Example 1 was not used. The results are shown in Table 2.

Comparative Example 6 0.5g of M-work instead of the high-density polyethylene of Example 1
/l 0 min, q degree 0.9 /) 2 g/C
m.

The same procedure was carried out except that HLM/M 60 high-density polyethylene was used. The results are shown in Table 2.

Claims (1)

[Claims] +1) (1) 70 to 95 parts by weight of an ethylene polymer or ethylene/α-olefin copolymer having the following properties (A) to (C), (B) ASTM'D 121E Melt flow index based on measurement method: 1 g/10 m'in or less, (0) Melt flow index based on measurement method of ASTM D 1238E and ASTM D12313F
Ratio HL of melt flow index based on the measurement method of
M work/M work is 40 or less. (1) High pressure low density polyethylene, ethylene/vinyl acetate copolymer, ionomer and density 0.955 g
5 to 60 parts by weight of at least one selected from the group consisting of ethylene/α-olefin copolymers having /C171 or less (however, i+l is 1η0 parts by weight), alkylsulfonic acid or alkylbenzenesulfonic acid 0.01 to 5 parts by weight of at least one magnesium salt or calcium salt of sulfonic acid selected from the following, and if necessary, 0.05 parts of at least one selected from dibenzylidene sorbitol or its nuclear substituted product.
A polyethylene composition comprising from 0 to 5 Mft. (2) [■] Components are ethylene and α having 6 to 16 carbon atoms
- Copolymer with olefin, having an ethylene content of 75 to 95 mol% and a density of o, sp to 0.9 i g
/L11, M work is 4-Og/10 min or less, x
The polyethylene composition according to claim 1, which is an ethylene/α-olefin copolymer having a degree of crystallinity according to i of 20% or less.