JPS5962655A - Polyethylene composition - Google Patents

Abstract

PURPOSE:To provide a polyethylene composition free from the tendency of surface roughening by extrusion and whitening by drawing at a high draw ratio, and suitable for the monofilament, by adding calcium hydroxystearate in combination with a specific higher fatty acid. CONSTITUTION:100pts.wt. of a polyethylene having a melt flow rate of preferably 0.1-1.0g/10min and a density of preferably 0.945-0.970g/cm<3> is compounded with 0.05-1.5pts.wt., preferably 0.5-1.0pt.wt. of calcium hydroxystearate and 0.01-0.5pt.wt., preferably 0.05-0.3pt.wt. of a 12-16C higher saturated fatty acid. USE:The monofilament prepared from the composition is suitable as a yarn stock of rope, and stock fiber for fishing net and net.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyethylene composition having good extrudability. More specifically, the present invention relates to a polyethylene composition suitable for monofilament, which has a good surface condition and excellent transparency.

Generally, various lubricants are used in thermoplastic resins such as polyethylene to improve fluidity during molding and to reduce friction with extruders and dies. Among them,
Polyethylene, which has a relatively narrow molecular weight distribution, is used for monofilament, which is used as raw material for ropes, fishing nets, insect nets, brushes, textiles (tents, sawcloth), etc., because it is stronger and has better stretchability than before. On the other hand, such polyethylene tends to cause rough skin during extrusion molding, so a lubricant with excellent spreading effect is required.

As such lubricants, metal soaps such as calcium stearate, calcium hydroxystearate, calcium laurate, zinc stearate, and magnesium stearate are often used in polyolefins.

In addition, unlike other uses, monofilaments are usually stretched at a high stretching ratio of 6 to /θ to obtain high strength, so if the surface becomes rough during extrusion, the filament is likely to break during stretching. , under high stretching ratios, extremely small voids (microoids) are created in the filament,
The disadvantage is that the entire filament becomes white L7 and loses its commercial value. The most common method for improving skin roughness during extrusion molding is to add the above-mentioned lubricant, for example,
It has been proposed to add calcium hydroxystearate, hydroxystearic acid and/or stearic acid to polyethylene (Japanese Patent Publication No. 4'9-//1A, No. 2), but it has some effect in improving extrusion pressure. is increasing. However, at present, even such lubricants do not have much of an improvement effect in preventing whitening under high stretching ratios. Therefore, the present inventors investigated the development of a polyethylene composition that not only improves the surface condition but also has excellent transparency (less whitening under high stretching ratios). It was found that the object of the present invention could be achieved by using the above together, and the present invention was completed.

That is, the present invention adds O, OS to 13 parts by weight of calcium hydroxystearate and 0.0 to 0.03 parts by weight of higher saturated fatty acids having a carbon number of /C to /6 to 100 parts by weight of polyethylene. The present invention provides a polyethylene composition.

The polyethylene used in the present invention is generally mel) 70
- L/-t (MFRI ASTM D/, 23g,
E) is θθ/ to yog/ /θmin, preferably 0/y, θg//θm, and the sound density is 09. a homopolymer of ethylene or other α-olefin having a molar ratio of 1.1 liter/ton or less, in the range of n to θ 7 θ1/cnt, preferably θ 113 to θ 011/crl; For example, propylene, l-butene, /-
pentene, /″-hexengumethyl-/-hentea,
It is a copolymer with /-octene, /-decene, etc.

If the MFR is less than θθ/l/lo, the melt viscosity is high and molding is difficult, and the MFFI is less than θlj/10m1y.
If it exceeds r, the mechanical strength is poor. Density is θty3
ri/cr! If it is less than that, the rigidity will decrease and the stretchability will also be poor. If the value exceeds θq7θ, the nodule strength particularly decreases. Further, for monofilaments, those having a molecular weight distribution (weight average molecular weight/number average molecular weight) of 5 or less are preferable because they have excellent mechanical strength.

Calcium hydroxystearate (hereinafter sometimes referred to as 5t(oH)・Ch) is added to the polyethylene.
Higher fatty acids with a carbon number of 12 to 2 are added together with
A) specifically refers to lauric acid, n-tritesylenic acid,
These include myristic acid, n-pentadecylenic acid, palmitic acid, and the like. Higher saturated fatty acids having a carbon number of /l or less are undesirable because they emit an odor during molding and cause significant dirt around the extruder die. On the other hand, even if higher saturated fatty acids having 17 or more carbon atoms are added, the effect of improving whitening resistance is small.

The polyethylene composition of the present invention includes the polyethylene: 7
00 weight refers to parts, 5t(OH)-Ca is O,OS to 13 weight parts, preferably O,S to /θ weight parts, and the higher saturated fatty acid (A) is Oθ/ to O,S weight. 1 part, preferably 0.3 parts OθS to 0.03 parts. If the amount of 5t(oH)·Cia exceeds 1S parts by weight, the monofilament becomes cloudy and the stability of molding is impaired. If O,OS is less than parts by weight, there is no effect of improving extrusion pressure. Furthermore, if the amount of higher saturated fatty acids exceeds 0.3 parts by weight, the effect of improving transparency tends to be rather reduced, and the extruder die becomes noticeably fouled. If the amount is less than 0.001 parts by weight, the whitening resistance will not be improved.

The polyethylene composition of the present invention contains various compounding agents such as weathering stabilizers, heat stabilizers, antistatic agents, slip agents, pigments, dyes, and nucleating agents, which are usually added to polyolefins for the purpose of the present invention. It may be added as long as it does not cause any damage.

Compared to conventional compositions, the polyethylene composition of the present invention not only has good extrusion pressure, especially when made into monofilament, but also has less whitening phenomenon under high draw ratios, and has a lower maximum draw ratio. Because it can be made higher,
As a high-strength monofilament, it can be used for rope wire, fishing nets, etc.
Suitable for various uses such as yarn for nets.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these examples in any way unless it goes beyond the gist thereof.

Example 1 MFR: o, 3g g//θmin, density: o, qr
sll/d and molecular weight distribution: 3.3 high-density polyethylene: 100'ff (for the band, /, 2-hydroxycalcium stearate (/JOH) St-Oa):
/ parts by weight, lauric acid (La-Ac1d): θO/
Heavy-duty room and heat stabilizer: 0. Composition-1, which was granulated by adding and mixing 1 M part, was processed using lθmm extruder (resin temperature:
After melting at 300υ), nozzle (/mmyJ, land gm
Extrusion from nJ resin temperature = 3θO℃), cooling temperature 2 υ, stretching temperature: 10υ℃, stretching speed (high speed example) = IOθ
A monofilament of 80 denier was obtained under conditions of m1m1n and a stretching ratio of 70 to 73 times. Next, the undrawn yarn (extruded strand) and monofilament were evaluated by the following method.

Appearance of undrawn yarn: Observe the skin condition of undrawn yarn and give a rating in 3 levels.

Rating left (good) ← Rating/(bad) Transparency of monofilament: Visually evaluate the transparency of the drawn yarn and give a rating of S level.

Rating! (Transparent)←→Rating/(Whitening) Tensile test: Based on JIS L 1073.

Between spans: Sθorin Tensile speed: 00mTl/order Test temperature: 23υ The results are shown in Tables 1 and 2.

Example 1.3 In place of lauric acid (La-Aid) used in Example 1, myristyrenic acid (My-Acid) was used, respectively.
The same procedure as in Example 1 was carried out except that palmitic acid (Pa-Ac1c!) and palmitic acid (Pa-Ac1c!) were used. The results are shown in Tables 1 and 2.

Comparative Example/~Da Instead of lauric acid (La-Ac1d) used in Example 1, stearic acid (st-Acid), /
, 2-hydroxystearic acid (/co(oH)st-A
cicl), behenic acid (Be-Ac1d) fc
The same procedure as in Example 1 was carried out except for using. The results are shown in Tables 1 and 2.

Claims (1)

[Claims] (])Polyethylene: Calcium hydroxystearate is added from 00 to 13 times Fd:
part and carbon number /, 2 to /&, higher saturated fatty acid Oθ
1. A polyethylene composition characterized in that the left weight part of / to O is added.