JPS5982406A - Polyolefin yarn - Google Patents

Abstract

PURPOSE:To provide a polyolefin yarn composed of a linear low-density polyethylene and a crystalline polyolefin at a specific ratio, having excellent strength, drawability, high-speed formability, apearance, and flexibility, and useful for knit or woven fabric, bag, container, rope, etc. CONSTITUTION:A polyolefin yarn such as monofilament, split yarn, slit yarn, flat yarn, stretch tape, etc. composed of a polyolefin composition consisting of (A) 60-90wt% of a linear low-density polyethylene having a density of 0.89-0.94 g/cc (preferably a copolymer of 60-95mol% of ethylene and 5-40mol% of a 3-11C alpha-olefin and having a melt index of 0.5-7g/10min and an N value of 1.3-2.7) and (B) 10-40wt% of a crystalline polyolefin (preferably a high-density polyethylene having a density of 0.945-0.97g/cc and a melt index of 3-10g/ 10min).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flexible and strong polyolefin yarn, more specifically (a) linear low-density polyethylene with a density of 0.89-0.94 g/cc, 60-90% by weight; (b) Concerning a polyolefin thread consisting of a polyolefin composition containing 10 to 40% by weight of crystalline polyolefin.

Conventionally, crystalline polyolefins such as high-density polyethylene and polypropylene have been used because they have excellent properties such as heat resistance, cold resistance, water resistance, chemical resistance, impact resistance, abrasion resistance, and environmental stress cracking resistance. Polyolefin yarns such as monofilament yarns and tape yarns made of crystalline polyolefins are widely used in various applications such as ropes, fishing nets, and industrial weavers.

However, due to the high crystallinity of polyolefin yarns made of crystalline polyolefins that have such excellent properties, they cause stretching unevenness and whitening phenomenon during stretching, reducing the physical properties of the monofilament and reducing its commercial value. It not only reduces flexibility, high-speed formability,
It is inferior in appearance etc. Further, when weaving these polyolefin threads, vertical cracks occur, often causing trouble in stopping the loom.

Therefore, in order to improve these drawbacks, attempts have been made to mix low density polyethylene, rubber, or a small amount of filler with the amount of conventional crystalline polyolefin spun alone, but these efforts have resulted in a significant decrease in linear strength, knot strength, etc. Unavoidable disadvantages such as Furthermore, at present, sufficient flexibility and high-speed moldability have not been obtained.

The present invention was made as a result of intensive studies to overcome the above problems, and it has excellent stretchability, high-speed formability, and
The purpose of the present invention is to provide a polyolefin yarn with excellent appearance and flexibility.

That is, the present invention provides a polyolefin yarn comprising (a) a polyolefin composition of 60 to 90% by weight of linear low-density polyethylene having a density of 0.89 to 0.94 a/cc and (b) 10 to 40% by weight of crystalline polyolefin. It is.

The linear low density polyethylene of the present invention having a density of 0.89 to 0.94 g/cc generally means 60 to 95 mol%.
A copolymer consisting of ethylene and 5 to 40 mol% of an α-olefin having 3 to 12 carbon atoms, such as ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer Copolymers, ethylene-4-methylpentene-1 copolymers, ethylene-octene-1 copolymers, etc. may be mentioned, but copolymers with α-olefins having 4 to 10 carbon atoms are particularly preferred. Moreover, these copolymers may be those copolymerized with two or more types of α-olefins. The method for producing these copolymers is not particularly limited, and may include a high pressure method, a gas phase method using a medium or low pressure method, a slurry method, a solution method, and the like.

The density of the above linear low density polyethylene is 0.89 to 0.9
4 gloC, but if the density of linear low density polyethylene is 0.139 g/cc without swirling, the strength will decrease, and if it exceeds 0.94 g/cc, the flexibility and texture of the fiber will decrease. Alternatively, high-speed moldability etc. may be impaired.

Furthermore, the melt index (hereinafter simply referred to as Ml) of the linear low density polyethylene is 0.2 to 15 g/10 min, preferably 0.5 to 7 g/10 min, and the N value is 1.2 to 3.01.
Preferably, the range is 1.3 to 2.1.

On the other hand, the crystalline polyolefin of the present invention has a density of 0.
945 or more, preferably 0.945 to 0.97 (]
/CC ethylene homopolymer or copolymer with α-olefin mainly composed of ethylene, or homopolymer of α-olefin such as crystalline polypropylene, polybutene-1, poly-4-methylpentene-1, or copolymers containing α-olefins thereof as a main component, and mixtures thereof. The melt index of the above-mentioned crystalline polyolefin is not particularly limited, but generally, for example, for high density polyethylene and polypropylene, a range of 0.3 to 10 o/10 min is preferable.

In the present invention, the mixing ratio of linear low-density polyethylene and crystalline polyolefin is important, and the crystalline polyolefin should be mixed at a ratio of 10 to 40% by weight to 60 to 90% by weight of the linear low-density polyethylene. is necessary. The mixing ratio of the above crystalline polyolefin is 10% by weight
If it is less than that, the stretchability and rigidity will be poor;
If it exceeds 40% by weight, the drawdown properties will be reduced, the high-speed moldability will be poor, and the flexibility of the fiber will be impaired. Additionally, there is a risk that vertical cracking may occur during weaving.

Note that the melt index of the mixture of crystalline polyolefin and linear low density polyethylene is not particularly limited;
When mixing, care must be taken to avoid crosstalk.

Further, other commonly used additives such as antioxidants, ultraviolet inhibitors, antistatic agents, coloring pigments, etc. may be appropriately added to the polyolefin composition of the present invention.

The polyolefin yarn of the present invention is a monofilament yarn obtained by melt-spinning and drawing the above-mentioned polyolefin composition, or a split formed by producing a film from the above-mentioned composition, splitting the film into a ribbon shape, and axially stretching it. yarn,
Alternatively, it includes common yarns such as slit yarns, flat yarns, stretched tapes, continuous yarns, and the like.

The fineness of the polyolefin yarn is generally selected in the range of 30 to io, ooo deniers, particularly in the range of 300 to 3,000 deniers for commonly used ropes, fishing nets, cloths, and the like.

One of the most notable features of the polyolefin yarn of the present invention is that it has the advantage of being able to continuously obtain ultrafine yarns of around 50 denier at high speed due to its good high-speed moldability. Producing thin threads by performing such high-speed forming reduces knot strength, linear strength, etc., and it has not been possible to obtain strong threads.

Another feature of the present invention is that it eliminates the vertical crack edges that occur when using tape yarns with a high fineness of 2,000 denier or more, so they can be folded double or triple for use. Since the weaving density can be greatly increased and the Young's modulus is low, it is possible to provide knitted fabrics etc. that are strong and highly flexible.

As mentioned above, by using a specific composition, the polyolefin yarn of the present invention has great flexibility, has excellent strengths such as knot strength and linear strength, and has good high-speed moldability, so it has high productivity. It has no surface roughness and has an excellent appearance, and is widely used in many fields such as various knitted fabrics, bags, containers, robes, and core materials for belts.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these unless it departs from the gist thereof.

High-density polyethylene (manufactured by Yagoku Kagaku Co., Ltd., Stafrene E71)
0, melt index 0.85, density 0.956
) and linear low-density polyethylene (manufactured by Yasseki Kagaku Co., Ltd., Linirex AF2320, melt index 1.0, density 0
．． 922) in the proportions shown in Table 1, and then spun into monofilament 1 of 400 denier using a 40 mm extruder manufactured by Modern Co., Ltd. under conditions of a resin temperature of 280° C. near the spinneret. Table 1 shows the linear strength and elongation, knot strength and elongation, Young's modulus, and drawability of this monofilament that was stretched 8.0 times at a water temperature of 97°C. The linear strength and elongation, knot strength and elongation, and Young's modulus were measured according to JIS-L1073, and the drawability was expressed as the draw ratio when the monofilament whitened under the above drawing conditions.

In addition, when keeping the distance 111i (air gap) between the spinneret and the water surface of the cooling water tank, the extrusion amount, and the water temperature of the cooling water tank constant, and smoothly increasing the take-up speed of the undrawn yarn, it is possible to The resin finally breaks. The maximum take-off speed at this time is shown in Table 1 as a measure of high-speed formability or fine denier.

For comparison, high-density polyethylene (manufactured by Yasoku Kagaku Co., Ltd., Stafrene E
710. Melt index 0.85, density 0.956
) to high-pressure low-density polyethylene (manufactured by Yasseki Kagaku Co., Ltd., Rexron F22, melt index 1.1, density 0.92
2) was mixed, monofilament was spun in the same manner, and 11 similar measurements were carried out.The results are shown in Table 1. As a result, it has poor stretchability, high-speed formability, straightness and knot strength.

Example 3 High-density polyethylene (Meltoidtex 7.0, density 0.962) and linear low-density polyethylene (melt index 0.62, density 0.922) were pellet-blended in the proportions shown in Table 1. A monofilament was obtained by spinning in the same manner as in Example 1.

This monofilament was measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 Isotactic polypropylene (manufactured by Yasseki Kagaku Co., Ltd., Nisseki Polypro FH-G, melt index 4.0) and linear low-density polyethylene (manufactured by Yasseki Kagaku Co., Ltd., Linirex A)
F2320, Mel [~index 1.0, density 0.9
22) were pellet-blended in the proportions shown in Table 1, and then spun in the same manner as in Example 1 to obtain monofilaments.

This monofilament was measured in the same manner as in Example 1, and the results are shown in Table 1.

High-density polyethylene (manufactured by Yasseki Kagaku Co., Ltd., used in Example 1)
A monofilament was obtained by spinning in the same manner as in Example 1 using only Stafrene E710 (melt index: 0.85, density: 0.956).

This monofilament was measured in the same manner as in Example 1, and the results are shown in Table 1. As a result, flexibility and high-speed moldability were poor.

Using only the polypropylene used in Kukko Kanto Example 4, Example 1
Measurements were carried out in the same manner as above, and the results are shown in Table 1. As a result, the flexibility and stretchability were poor.

This 11L using only the linear low density polyethylene used in Example 1,
Measurements were carried out in the same manner as in Example 1, and the results are shown in Table 1. As a result, the knot strength and stretchability were poor.

Claims (1)

[Claims] 1. From a polyolefin composition (a>60 to 90% by weight of linear low density polyethylene with a density of 0.89 to 0.94 g/cc, (b) 10 to 40% by weight of crystalline polyolefin) 2. The linear low density polyethylene is ethylene-butene-
1. The polyolefin yarn according to claim 1, which is a copolymer. 3. The crystalline polyolefin has a density of 0.945 (1/
The polyolefin yarn according to claim 1 or 2, which is high-density polyethylene of CC or higher. 4. The polyolefin thread according to claim 1 or 2, wherein the crystalline polyolefin is polypropylene.