JP3401106B2 - Polyolefin yarn fabric - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to a polyolefin yarn woven fabric,
More specifically, the present invention relates to a polyolefin yarn woven fabric useful as a protective sheet for columnar objects such as columnar mechanical parts, tree trunks, and underground cylindrical buried objects.

[0002]

2. Description of the Related Art When transporting a columnar mechanical part such as a metal shaft, the shaft is made of a polyolefin yarn woven fabric such as polyethylene filament in order to avoid direct contact between the metal shaft and the obstacle when the shaft collides with the obstacle. A polyethylene yarn woven fabric obtained by plain weaving is used for protection.

When the shaft is protected by a polyolefin yarn woven fabric and conveyed, the direction in which the obstacles collide is substantially constant with respect to the polyolefin yarn woven fabric. Therefore, it is required that the polyolefin yarn woven fabric has sufficient damage resistance in that direction.

On the other hand, the polyolefin yarns that make up the polyolefin yarn woven fabric, including the polyethylene yarn woven fabric obtained by plain weaving, generally have the same number of warp yarns and weft yarns. The sexes are almost the same. Therefore, when a large damage resistance is required only in a specific direction, it is dealt with by using the polyolefin yarn woven fabric in multiple layers. This approach is not very economical as it is reinforced to the extent that less damage resistance is required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyolefin yarn woven fabric which can meet the demand at low cost when damage resistance is required in a specific direction. .

[0006]

The above objects and advantages of the present invention include a polyolefin single yarn having a strength of 6 to 10 g / denier, a tensile breaking strength Sm in the direction having the highest tensile breaking strength and a direction perpendicular to the direction. The tensile breaking strength St of S satisfies the following formulas (1) and (2) Sm ≧ 100 kg / inch (1) Sm / St ≧ 1.5 (2) It is achieved by a polyolefin yarn woven fabric for a protective sheet for a columnar object .

The polyolefin yarn woven fabric provided by the present invention should be used such that the direction in which damage resistance is most required at the time of its use is perpendicular to the direction in which the polyolefin yarn woven fabric has the highest tensile breaking strength Sm. Thus, for example, it functions sufficiently as a protective sheet and is low in cost.

Hereinafter, the present invention will be described in detail, by which other objects, configurations, advantages and effects of the present invention will be apparent.

The polyolefin yarn woven fabric of the present invention is composed of a single polyolefin yarn. As the polyolefin, a polyethylene resin such as high-density polyethylene, medium-density polyethylene, or low-density polyethylene (L-LDPE, LDPE); polypropylene, propylene, ethylene, 1-butene or the like having 1 to 10 carbon atoms other than propylene
Of a polypropylene-based resin such as a propylene random copolymer obtained by copolymerizing a small amount of α-olefin, a block copolymer of the above α-olefin and propylene; and a polybutene-based resin and a poly-4-methyl-1-pentene-based resin. Can be illustrated.

Among them, polyethylene resin is preferable,
In particular, high density polyethylene having a density of 0.95 or more is preferable. Then, the melt flow rate of the polyethylene resin (ASTM D1238, temperature 190 ° C., load 2.16)
(measured in kg) is preferably 0.05 to 50.

The above-mentioned polyolefins may be used alone or in combination to form a polyolefin single yarn. If desired, the polyolefin may contain known antioxidants, light stabilizers, colorants, lubricants, antistatic agents, flame retardants, fillers and the like.

Titanium oxide, zinc titanate, zirconium oxide, zinc sulfide, antimony oxide, and the like can be used as fillers.
Examples include zinc oxide, lithopone, magnesium oxide, alumina, calcium carbonate, talc, kaolin, clay, mica, silica, quartz powder, diatomaceous earth, barium sulfate, pumice powder, wood powder, bamboo powder, cork powder and carbon black. be able to.

The polyolefin is a thermoplastic resin such as polystyrene resin, polyvinyl chloride resin, polyamide resin, polyester resin, polyacetal resin or polycarbonate resin, SBR, IR, BR, NB.
R, natural rubber, a diene rubber exemplified by EPR, E
It may contain a small amount of olefinic rubber exemplified by PPM, for example, 10% by weight or less.

Examples of the polyolefin single yarn include those produced from the above-mentioned polyolefin by the methods known per se exemplified in the following (a) to (c). (A) Filament yarn: produced by melt spinning and drawing. (B) Tape-shaped yarn (flat yarn): It is obtained by forming a film or sheet by a casting method, an inflation method or the like, slitting the film or sheet, and stretching it. (C) Split yarn (split yarn): Obtained by further splitting the flat yarn.

In the present invention, the strength of the polyolefin single yarn is 6 g / denier or more, preferably 6.5 g / denier or more, and it is recommended to use the polyolefin single yarn having the highest possible strength. Depending on the type of polyolefin used, the upper limit of the strength of the polyolefin single yarn is 8 to 10 g.
/ It is denier. Strength of polyolefin single yarn is 6g /
In order to obtain a denier or more, in the case of the filament yarn, the tape-shaped yarn, and the split yarn described above, the degree of stretching can be adjusted. Although the thickness of the polyolefin single yarn is not particularly limited, it is generally 100 to 5000 denier.

The polyolefin yarn woven fabric of the present invention has a tensile breaking strength Sm of 10 in the direction having the highest tensile breaking strength.
It is 0 kg / inch or more, that is, it satisfies the formula (1), and is preferably 150 kg / inch or more.

The polyolefin yarn woven fabric of the present invention further satisfies the above mathematical expression (2). That is, the tensile breaking strength Sm in the direction having the highest tensile breaking strength is 1.5 times or more the tensile breaking strength St in the direction perpendicular to the direction. Preferably, the following mathematical expression (3) Sm / St ≧ 2 (3) is satisfied. The value of St is preferably 10 kg / inch or more,
It is more preferably 20 kg / inch or more.

Here, the strength of the polyolefin single yarn is J
It is a value measured according to IS L 1013-1992. Further, the tensile breaking strength of the polyolefin-based fabric is
It is a value measured according to JIS L 1096-1990.

The polyolefin yarn woven fabric of the present invention can be obtained by weaving the above-mentioned polyolefin single yarn by a method such as plain weave or twill weave.

Then, for example, in order to make the longitudinal direction the direction having the greatest tensile breaking strength, it is described as follows (a)
The methods of (c) to (c) can be exemplified. (A) Polyolefin single yarn in the longitudinal direction (hereinafter simply referred to as "warp yarn")
In some cases, the number of yarns of the polyolefin single yarn (hereinafter sometimes simply referred to as “weft yarn”) in the transverse direction is set to be larger than the number of yarns of the polyolefin single yarn in the transverse direction. FIG. 1 schematically shows an example in which the number of warp threads 2 is set to 2 every other unit, and the total number of warp threads 2 to be driven is increased by 50% from the total number of weft threads 3 to be driven. Of course, two warp threads may be provided for each unit, and the total number of warp threads to be driven may be twice the total number of weft threads to be driven. FIG. 2 is a diagram schematically showing another example manufactured by the above method (a).

(B) A method of using thick polyolefin single yarn as the warp yarn. That is, it is a method of using a polyolefin single yarn whose thickness is, for example, 1.5 times or more thicker than that of the weft yarn as the warp yarn. In this case, the number of warp threads and the number of weft threads may be the same, or the number of warp threads may be increased.

(C) A method of using a polyolefin single yarn having high strength as the warp yarn. In this method, the warp yarn has a strength per denier of about 1.5 than that of the weft yarn.
This is a method of using double or more polyolefin single yarns. In this case, the number of warp threads and the number of weft threads may be the same, or the number of warp threads may be increased.

The above methods (a) to (c) can be used alone or in combination. Further, the polyolefin single yarns used for the warp yarn and the weft yarn may be different in the type of polyolefin, the shape of the yarn, and the like.

Whichever method is adopted, by carrying out a simulation in advance and confirming experimentally, the direction having the largest tensile breaking strength is defined as the longitudinal direction, and the tensile breaking strength St and the tensile breaking strength in the longitudinal direction are set. The strength Sm can be set to satisfy the above formulas (1) and (2).

In order to obtain a polyolefin yarn woven fabric in which the direction having the highest tensile breaking strength is the transverse direction, the case where the direction having the highest breaking strength is the longitudinal direction has been described above (a).
In the methods (c) to (c), the method in which the horizontal is replaced by the vertical and the vertical is replaced by the horizontal may be adopted as it is or in combination.

The damage resistance of the above-described polyolefin yarn woven fabric of the present invention against the cutting force applied thereto is maximized in the direction perpendicular to the direction in which the tensile rupture strength of the polyolefin yarn woven fabric is maximized. Therefore, when the polyolefin yarn woven fabric of the present invention is used as a protective sheet, it is used so that the direction in which the greatest cut force is applied to the protective sheet and the direction at which the tensile rupture strength of the woven fabric is maximum coincide with each other. Is highly preferred.

The polyolefin yarn woven fabric of the present invention is used for columnar machine parts, tree trunks, underground cylinders (water pipes, gas pipes).
It can be used as a protective sheet for columnar objects such as.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[Test Method for Cut Resistance (Damage Resistance) of Polyolefin Yarn Woven Fabric] A test is carried out using a test apparatus 31 whose side view is schematically shown in FIG. In the cut resistance tester 31, a scouring shaft (weight: 1.86 kg) 32 having a diameter of 25 mm and a length of 500 mm is placed on a column 33 so that it can be naturally dropped. At this time, the angle formed by the shaft 32 and the horizontal plane is 68 °, and the angle formed by the natural falling direction of the shaft 32 and the horizontal plane is 68 ° in the initial stage when the shaft 32 naturally falls. Shaft 3
As shown in FIG. 4, which is an enlarged schematic view of the tip portion 34 of FIG. 2, the M12 washer 4 is attached to the tip of the shaft 32.
1 is attached. The outer diameter of the washer 41 is about 25
mm, the inner diameter is about 12.5 mm, and the thickness is about 2.3 mm. It should be noted that the shaft 32 is fixed to the support column 33 with a retainer (not shown) or the like before being naturally dropped. The interval between the lowest position 39 of the washer 41 attached to the shaft 32 and the horizontal plane 38 on which the DUT 37 (polyolefin fabric) is placed is 1 m. The horizontal surface 38 is a concrete surface.

In such a test apparatus 31, when the shaft 32 is naturally dropped from the support column 33, the shaft 32 falls along the dotted line 35, and about a point 40 where the vertical line from the lowest position 39 of the washer 41 and the horizontal plane 38 intersect. Since the edge portion of the washer 41 attached to the tip of the shaft 32 collides with the horizontal surface 38 near the position 36 separated by 30 cm, the device under test 37 is placed so that the substantially central portion of the device under test 37 is located at the position 36. Put. When the edge portion of the washer 41 collides with the horizontal surface 38, a stress in the horizontal direction momentarily acts strongly on the DUT 37 placed on the horizontal surface 38.

The test piece (polyolefin yarn woven fabric) 37 is placed in such a direction that the longitudinal direction (longitudinal direction) thereof and the stress generated at the time of collision are substantially at right angles, as schematically shown in FIG. is there. In this way, the degree of the cut caused on the test object due to the natural fall and collision of the shaft 32 is observed. A test is performed 10 times on one polyolefin polyolefin woven fabric, and the following four-stage evaluation is performed. No damage after 4:10 tests. There is damage to one or all of the 3:10 tests, but there is no damage to the back of the fabric. All of them were damaged in 2:10 tests, and less than half of the damages were torn to the back of the fabric. All of them were damaged in the 1:10 test, and more than half of the damages were split to the back of the fabric.

Example 1 Using a 2000-denier polyethylene single yarn (strength: 6.5 g / denier), a plain weave fabric having 45 warps / inch and 15 wefts / inch was prepared. The direction in which this woven fabric has the highest tensile breaking strength is the longitudinal direction, its tensile breaking strength Sm is 580 kg / inch, and the lateral tensile breaking strength St is
Was 190 Kg / inch. The basis weight of this woven fabric was 532 g / m ² . As a result of a cut resistance test performed on this woven fabric, the score was 4.

On the other hand, for comparison, a woven fabric in which both warp and weft yarns were 15 / inch was produced using the above polyethylene single yarn (unit weight: 266 g / m ² ), and its cut resistance test was conducted. However, the evaluation was 1. Further, three pieces of this woven fabric were piled up (weight per unit area: 798 g / m ² ) and a cut resistance test was conducted, and the evaluation was 4. The comparative woven fabric (1 sheet) had a tensile breaking strength of 1 in both the longitudinal and transverse directions.
It was 95 kg / inch. The above results are shown in Table 1.

[0034]

[Table 1]

It can be seen from Table 1 that the comparative product has a high damage resistance in the lateral direction of 4 by stacking three sheets, but has a high basis weight of 798 g / m ² and a high cost. In this case, it is clear that a protective sheet having a lower basis weight of 532 g / m ² and a cut resistance equivalent to that of the comparative three-ply laminate can be obtained, so that a protective sheet excellent in lateral damage resistance can be obtained at low cost.

Example 2 A woven fabric having 30 warps / inch and 15 wefts was produced in the same manner as in Example 1. The direction in which this fabric has the highest tensile breaking strength is the longitudinal direction, and its tensile breaking strength Sm is 390 kg /
The transverse breaking strength St was 193 kg / inch, and the basis weight was 355 g / m ² . A damage resistance test was conducted by stacking three sheets of this woven fabric.

On the other hand, as a comparison, a damage resistance test was conducted on six fabrics of the comparative product prepared in Example 1 which were stacked. The above results are shown in Table 2.

[0038]

[Table 2]

From the results shown in Table 2, it can be seen that the product of the present invention can provide a protective sheet with a small basis weight, that is, at a low cost and excellent in lateral damage resistance.

[0040]

The polyolefin yarn woven fabric of the present invention can meet the demand at a low cost when sufficient strength is demanded in a specific direction.

[Brief description of drawings]

FIG. 1 is a schematic view showing one embodiment of a polyolefin yarn woven fabric of the present invention.

FIG. 2 is a schematic view showing one embodiment of the polyolefin yarn woven fabric of the present invention.

FIG. 3 is a schematic side view of a damage resistance test apparatus for a polyolefin yarn woven fabric.

FIG. 4 is a schematic view of a tip portion of a shaft of a damage resistance test device.

FIG. 5 is a plan view schematically showing the positional relationship between the damage resistance test device and the device under test.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Polyolefin yarn woven fabric 2 Warp yarn 3 Weft yarn 11 Polyolefin yarn woven fabric 12 Warp yarn 13 Weft yarn 31 Cut resistance test device 32 Shaft 33 Strut 34 Tip part 35 of shaft 32 Dotted line 36 showing the trajectory of the tip part when the shaft 32 falls naturally 36 Shaft Washer 4 attached to the tip of 32
The position where the edge part of 1 collides with the horizontal surface 38 37 The DUT 38 The horizontal surface 39 The lowest position 40 of the washer 41 The point 41 where the vertical line from the lowest position 39 of the washer 41 and the horizontal surface 38 intersect

Claims (5)

(57) [Claims] 1. A tensile rupture strength Sm in a direction having the highest tensile rupture strength and a tensile rupture strength S in a direction perpendicular to the direction, which consists of a polyolefin single yarn having a strength of 6 to 10 g / denier.
t is the following equation (1) and (2) Sm ≧ 100 kg / inch ····· (1) Sm / St ≧ 1.5 ····· (2) of the columnar body, characterized in that to satisfy the Polyolefin yarn woven fabric for protective sheet . 2. The polyolefin yarn woven fabric according to claim 1, wherein the polyolefin single yarn is a polyethylene resin filament yarn, tape-like yarn or split yarn. 3. The polyolefin yarn woven fabric according to claim 1, wherein the direction having the highest tensile breaking strength is the longitudinal direction. 4. The polyolefin yarn woven fabric according to claim 3, wherein the number of warp yarns is greater than the number of weft yarns. 5. The polyolefin yarn woven fabric according to claim 1, which has a tensile breaking strength St of 10 kg / inch or more.