JPH0610233A - Ultrahigh molecular weight polyethylene woven fabric - Google Patents

Abstract

PURPOSE:To obtain the title woven fabric having excellent strength and high abrasion resistance by weaving the drawn tapes obtained from the slit films of polyethylene under specific conditions. CONSTITUTION:Polyethylene film of superhigh molecular weight of more than 5dl/g or higher in intrinsic viscosity is slitted and drawn at least 2 draw ratio in at least the longitudinal direction at 100 to 150 deg.C. The resultant drawn tapes are woven or the drawn tapes are cooled down lower than 80 deg.C and opened at an opening ratio of from 0.5 to 4.0 and the split yarns are used for weaving.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ultra high molecular weight polyethylene woven fabric.

[0002]

2. Description of the Related Art Ultra-high molecular weight polyethylene is superior to general-purpose polyethylene in impact resistance, abrasion resistance, chemical resistance, tensile strength, etc., and is expected to be used not only as engineered plastic but also as a fiber material. Has been done.

By the way, this ultra-high molecular weight polyethylene is poor in moldability, and a molding method (extrusion molding, injection molding) carried out in ordinary polyethylene or polypropylene is used.
Molding was difficult.

In view of these points, the present applicants have proposed various techniques for producing ultrahigh molecular weight polyethylene films, stretching techniques, and the like. For example, Japanese Patent Application Laid-Open No. 62-122736 proposes a method for producing a film, and Japanese Patent Application Laid-Open No. 63-203816 proposes a stretching method for this film.

[0005]

By the way, in the above-mentioned prior art, there is no mention of the defibration technique, and it is a technical problem how to defibrate the stretched tape obtained by the above-mentioned conventional technique. Therefore, a split yarn made from ultra-high molecular weight polyethylene has not been realized, and a woven fabric using the split yarn has not been known. Further, although a stretching method for the stretching tape has been proposed, a woven fabric made of the material is not known.

The present invention has been made in view of the above points, and an object thereof is to obtain excellent impact resistance, abrasion resistance, chemical resistance, tensile strength and the like using ultra high molecular weight polyethylene as a raw material. It is to provide technology for realizing woven cloth.

[0007]

According to the present invention, an ultrahigh molecular weight polyethylene film having an intrinsic viscosity (η) of 5 dl / g or more is slit, and the slit film is cut at least in the longitudinal direction at a temperature of 100 ° C to 150 ° C. A woven fabric obtained by weaving a stretched tape (hereinafter, simply referred to as a stretched tape) obtained by stretching the stretched tape by 2 times or more, and after cooling the stretched tape to 80 ° C. or lower, a defibration ratio (roll peripheral speed / tape speed) ) 0.5 ~
A woven fabric obtained by weaving a split yarn obtained by defibration in 4.0 (hereinafter, simply referred to as a split yarn), and a production method thereof.

That is, the woven fabric of the present invention is produced by the steps of producing a stretched tape made of ultra-high molecular weight polyethylene or split yarn obtained by defibrating this, and weaving these. Hereinafter, the present invention will be described in detail.

<1> Ultra High Molecular Weight Polyethylene Used in the Present Invention The ultra high molecular weight polyethylene used in the present invention has an intrinsic viscosity (η) measured at 135 ° C. in a decalin solvent of 5 dl / g or more, preferably 8 to 25 dl. / g and melt flow rate (MFR: ASTM D1238, F) is 0.01 g / 10
A homopolymer of ethylene of min or less or ethylene and other α-olefins such as propylene, 1-butene, 1-
It is a copolymer mainly composed of ethylene such as hexene, 1-octene and 4-methyl-1-pentene, which is crystalline.

If desired, various stabilizers may be added to the ultrahigh molecular weight polyethylene. Examples of this stabilizer include tetrakis [methylene (3,5-di-t
-Butyl-4-hydroxy) hydrocinnamate] methane, a heat-resistant stabilizer such as distearylthiodipropionate, or bis (2,2 ′, 6,6′-tetramethyl-4-piperidine) sebacate, 2- ( Examples thereof include weathering stabilizers such as 2-hydroxy-t-butyl-5-methylphenyl) -5-chlorobenzotriazole.

An inorganic or organic dry color may be added as a colorant. <2> Stretching Tape and Split Yarn Used for the Woven Fabric of the Present Invention The stretched tape used for the present invention is obtained by stretching the ultra high molecular weight polyethylene by the method described below, and has an intrinsic viscosity (η) of 5 dl. / g or more, preferably 7 to 2
It is a drawn tape of 5 dl / g.

The split yarn used in the present invention is obtained by defibrating the drawn tape by the method described below, and has an intrinsic viscosity (η) of 5 dl / g or more, preferably 7 to 25.
dl / g, tensile strength is 7 g / denier or more, preferably 10 g /
It is a split yarn having a denier or more and usually 30 to 20,000 denier, preferably 100 to 5,000 denier.

The stretched tape used in the present invention is produced by forming a film from the above-mentioned ultrahigh molecular weight polyethylene having an intrinsic viscosity (η) of 5 dl / g or more, then slitting this film, and then 100 ° C to 150 ° C. It can be obtained by stretching the film at least twice in the machine direction at a temperature, preferably 4 to 10 times.

The split yarn used in the present invention has a defibration ratio (roll peripheral speed / tape speed) of 0.5 to 4.0, preferably 1.0 after the drawn tape is cooled to 80 ° C. or lower.
It is obtained by defibrating at about 2.0.

As a method for producing a film used for stretching, there are the following methods. In the first method, an ultrahigh molecular weight polyethylene having an intrinsic viscosity (η) of 5 dl / g or more is used in a screw extruder, preferably a grooved cylinder (barrel).
Melted in a screw extruder equipped with a mandrel which then rotates with the screw rotation of at least L /
D is 5 or more, preferably 10 or more, more preferably 20.
After extruding from a tube die of ~ 70, gas is blown into the inside of the tubular film in a molten state so that the expansion ratio is 1.1 ~.
20 times, preferably 1.5 to 12 times expanded to give a melting point −
A film is obtained which undergoes a heat shrinkage of 10% or more in the transverse direction at a temperature of 5 ° C.

When the intrinsic viscosity (η) is less than 5 dl / g, the mechanical strength such as tensile strength at break, impact strength, etc. is not sufficient, and when heat shrinks, the film softens and loses its shape as a film. Will end up. Further, since the melt viscosity is low, twisting due to co-rotation of the melt of the ultra high molecular weight polyethylene and the mandrel in the tube die and uneven thickness due to bending of the mandrel are likely to occur, resulting in non-uniform moldability.

The melt of ultra-high molecular weight polyethylene has an extremely high viscosity as compared with the melt of general-purpose polyethylene.
Since it is a rubber-like viscous material, a tube die with an L / D of less than 5 does not become a completely homogeneous melt before being extruded from the die, so gas inside the tubular film extruded from the die When blown in, the tube does not swell evenly or breaks, and a good film cannot be obtained.

The tube die mandrel must be rotated as the screw of the extruder is rotated. The rotation speed of the mandrel does not necessarily have to be the same as the rotation speed of the screw.

The gas blown into the tubular film is usually air, but nitrogen or the like may be used. Melting point -5 ° C
A film having a heat shrinkage in the transverse direction of less than 10% at a temperature of 10 can obtain a tensile strength of 7 g / denier or more, but the longitudinal tear strength may be less than 150 g / mm. If the draw ratio is less than 2 times, the tensile strength may not exceed 7 g / denier.

As a method of producing a film used for stretching, a method of continuously cutting with a knife from the outer skin of a round bar obtained by a compression molding method or an extrusion molding method, and a fluidity improving agent such as wax are added. There is a T-die film molding method obtained from the above ultra-high molecular weight polyethylene.

However, the method of cutting with a blade cannot obtain an unfixed length of the raw material for stretching. Further, the T die film molding method has complicated molding steps. Therefore, the raw material used for the stretched tape is preferably a tubular film in terms of economy.

In the defibration process, if defibration is performed under a temperature condition of higher than 80 ° C., defibration becomes difficult and defibration or uneven defibration may occur. If the defibration ratio is smaller than the above value, the fiber becomes rough,
When it is large, the mesh is fine, and it tends to be feather-like, and the strength tends to decrease.

The defibration process is performed with a porcupine cutter, a spiral cutter, or the like. Here, the stretched tape of ultra-high molecular weight polyethylene obtained in the above step has high strength, and therefore, defibration treatment with a porcupine cutter is preferable.

At this time, it is preferable that the porcupine needles are staggered or screwed in the flow direction at intervals of 0.5 to 2 mm in the width direction and 1 to 10 mm in the flow direction. The needle tip length is preferably 1 to 10 mm.

<3> Ultra High Molecular Weight Polyethylene Woven Fabric The woven fabric of the present invention can be obtained by weaving the above stretched tape or split yarn as a material.

Further, these may be mixed with a stretched tape or split yarn made of, for example, general-purpose polyethylene or polypropylene as a raw material. When the split yarn is used as the material, the fibers forming the warp yarns and the weft yarns may be used as a bundle, or the stretched tape may be used in the disentangled tape form.

The weaving method is not particularly limited, and a plain weave, a twill weave, a satin weave, or a pile weave, a double weave, a pattern weave or the like in which these are combined or changed can be adopted as the weave structure. In order to obtain a product with sufficient strength and wear resistance, the number of warp threads and weft threads should be 5 /
It is preferably at least inches.

The woven fabric obtained as described above can be used as a filter having excellent heat resistance, cold resistance and chemical resistance. For example, it is suitable as a member that requires heat resistance during use as well as chemical resistance, such as a diaphragm of a battery. Further, it is also suitable as a filter for preventing freezing of platelets by taking advantage of the cold resistance characteristic.

Furthermore, since it is particularly excellent in strength and abrasion resistance, it can be widely used as a woven fabric.
For example, canvas, explosion-proof sheet, protective clothing for preventing cuts, cloth such as safety gloves, various heavy cloths, electric cables, tension members and the like can be exemplified.

The woven fabric of the present invention can also be used as one material constituting a composite material. For example, sports equipment such as helmets, sailboards, skis, acoustic materials such as speaker diaphragms, industrial materials such as industrial helmets, construction civil materials such as building material reinforcement materials, automobiles, armor boards, transportation equipment such as ship members, It can be used as a material for a telecommunication member such as a radar dome.

[0031]

EXAMPLES Next, the present invention will be explained based on examples, but it goes without saying that the present invention is not limited to the following examples without departing from the gist thereof. <Production process of ultra high molecular weight polyethylene film> Ultra high molecular weight polyethylene powder ((η): 13.8 dl / g, MF
R: less than 0.01 g / 10 min, melting point: 136 ° C., bulk density: 0.45 g / cc), an outer die / mandrel = 20/17 mmφ, a 30 mmφ extruder connected to a cylinder temperature of 280 ° C. Die temperature 170 ℃, screw speed 15rpm, pinch roll 1.
While pulling at a speed of 2 m / min, compressed air was blown from a gas flow passage of 6 mmφ extending inside the screw and inside the mandrel of the tube die to expand the tube to a size that contacts the cooling ring inner diameter 82 mmφ ( An ultrahigh molecular weight polyethylene film having a swelling ratio of 4.1), a folding width of 128 mm and a thickness of 60 μm was produced. The heat shrinkage percentage at 131 ° C. of this film was 20.4% in the lateral direction and 10.6% in the longitudinal direction.

<Production of Ultra High Molecular Weight Polyethylene Stretched Tape> The above film was slit in the longitudinal direction with a width of 30 mm and used as a raw fabric. Next, this raw fabric was stretched 6 times (1 stage stretch) in an air oven stretching tank at 140 ° C.

<Disentangling Treatment of Stretched Tape> The stretched tape obtained above was cooled, the temperature of the stretched tape itself was set to 80 ° C. or lower, and then disintegrated by a porcupine cutter.

The characteristics of the split yarn thus obtained are shown in Table 1 together with other comparative examples.

[0035]

[Table 1]

As is clear from these results, the drawn tape and split yarn made from ultra-high molecular weight polyethylene are much superior in tensile strength to those made from general-purpose polyethylene.

<Manufacture of Woven Fabric> (Manufacturing Example 1) First, the stretched tape obtained as described above was woven using a Sruzer loom. The woven fabric thus obtained has a rougher texture than that of a material made of split yarn, but is more excellent in tensile strength.

(Production Example 2) Next, an example of production of a woven fabric in which split yarns are used as warp yarns and weft yarns will be shown. 1000d split yarns were woven using a Sruzer loom.

(Manufacturing Example 3) A manufacturing example using a tape-shaped split yarn obtained by defibrating a stretched tape is shown in FIG. This was woven using both warp and weft threads of 1000d.

Table 2 shows the strengths of the woven fabrics of the above Production Examples 1 and 2 and the woven fabric using polypropylene defibrated yarn as a comparative product.

[0041]

[Table 2]

[0042]

The ultrahigh molecular weight polyethylene woven fabric of the present invention is particularly excellent in strength and abrasion resistance. Further, it has excellent low-temperature characteristics, and its strength is extremely large especially at low temperatures. According to the present invention, it is possible to provide a woven fabric having good chemical resistance and sliding characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a woven fabric in which warp yarns and weft yarns are plain-woven with a disentangled stretched tape as a unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location D02J 1/22 J (72) Inventor Takeshi Shiraki 6-1-2 Maki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Iwakuni Polymer Research Institute, Ishi Oil Chemical Co., Ltd.

Claims (4)

[Claims] 1. A film of ultra-high molecular weight polyethylene having an intrinsic viscosity (η) of 5 dl / g or more is slit, and 100 ° C. to 1 ° C.
An ultrahigh molecular weight polyethylene woven fabric obtained by weaving a stretched tape obtained by stretching this slit film at least twice in the machine direction at a temperature of 50 ° C. 2. A film of ultra-high molecular weight polyethylene having an intrinsic viscosity (η) of 5 dl / g or more is slit, and 100 ° C. to 1 ° C.
After the drawn tape obtained by stretching the slit film at least twice in the machine direction at a temperature of 50 ° C. is cooled to 80 ° C. or less, the defibration ratio (roll peripheral speed / tape speed)
An ultra high molecular weight polyethylene woven fabric obtained by weaving split yarn obtained by defibrating at 0.5 to 4.0. 3. An ultrahigh molecular weight polyethylene film having an intrinsic viscosity (η) of 5 dl / g or more is slit, and 100 ° C. to 1 ° C.
A method for producing an ultra-high molecular weight polyethylene woven fabric, comprising the steps of stretching the slit film at least twice in the machine direction at a temperature of 50 ° C. to obtain a stretched tape, and weaving the stretched tape. 4. A film of ultra-high molecular weight polyethylene having an intrinsic viscosity (η) of 5 dl / g or more is slit, and 100 ° C. to 1 ° C.
A step of stretching this slit film at least twice in the longitudinal direction at a temperature of 50 ° C. to obtain a stretched tape, and cooling the stretched tape to 80 ° C. or lower, and then defibration ratio (roll peripheral speed / tape speed) A method for producing an ultra-high molecular weight polyethylene woven fabric, comprising the step of defibrating at 0.5 to 4.0, and the step of weaving the split yarn obtained by the defibrating.