JP3021793B2 - Method for producing net-shaped knitted fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a net-shaped knitted fabric, particularly a net-shaped knitted fabric suitable for use for reinforcing an embankment for civil engineering or improving soft ground.

[0002]

2. Description of the Related Art The laying net method is widely used for improving soft ground and reinforcing embankment. As a laying net used in these methods, a lattice-shaped synthetic fiber knitted fabric made of a bundle of two kinds of synthetic fibers having different melting points and obtained by hot-melting fibers having a lower melting point (Japanese Patent Laid-Open No. 2-229263). Japanese Patent Application Laid-Open No. 62-250243), and a ventilated sheet obtained by coating a mesh-like woven fabric comprising a warp and a weft with a thermoplastic polymer are known.

[0003]

The characteristics required of the laying net for reinforcing the embankment include high resistance to tension and tear, excellent rigidity, and relatively uniform quality.

[0004] The method of using a bundle of two kinds of synthetic fibers having different melting points as described above is characterized in that the low-melting fiber of the yarn constituting the lattice-shaped knitted fabric, ie, the fiber to be melted, is changed to the high-melting fiber, ie, core yarn. Is not completely covered, it is difficult to completely fuse and integrate the intersection of the yarns by melting the low-melting fiber, and there is a problem that the adhesion strength at the intersection becomes insufficient. In addition, since the core yarn is exposed, the corrosion resistance and chemical resistance are insufficient, and even in the portion where the core yarn is coated, the light shielding property of the low melting point fiber on the coating side is insufficient. For this reason, there has been a problem that ultraviolet rays are deteriorated when left for a long time.

[0005] Further, in the method of coating a mesh-like woven fabric comprising a warp and a weft with a thermoplastic polymer, the coating operation is complicated and requires skill, so that it is difficult to uniformly coat the thermoplastic polymer. In addition, there has been a problem that a product having uniform resistance and rigidity to tension and tear cannot be obtained.

[0006] The present invention solves the above problems,
An object of the present invention is to provide a net-like knitted fabric having high resistance to tension and tear, high rigidity, excellent light resistance, uniform quality, and suitable as a net.

[0007]

SUMMARY OF THE INVENTION The present invention provides a coated yarn obtained by completely covering a synthetic fiber yarn with a slit film having a lower melting point than the synthetic fiber yarn and having a light-shielding property. The warp and weft of the base fabric are fused at the intersection of the warp and the weft by knitting or weaving the warp and the weft in a lattice to form a coarse base fabric, and then fusing the slit film. This is a method for producing a net-shaped knitted fabric, which is integrated.

In the present invention, the synthetic fiber yarn has a higher melting point than the slit-like film covering the synthetic fiber yarn, and does not substantially melt at the melting point of the film, that is, does not soften or deform. It is necessary that the difference in melting point is 20 ° C. or more,
In particular, the temperature is desirably 20 to 200 ° C. If the difference in the melting points is less than 20 ° C., a portion that does not melt is generated due to a variation in the heating temperature, or the core yarn is melted, so that the quality tends to vary.

Examples of the combination of the high melting point synthetic fiber and the low melting point slit film include a combination of a polyester fiber and a polyethylene film, a polyester fiber and a polypropylene film, and a combination of a high melting point polyester fiber and a low melting point polyester film. . Here, the low melting point polyester film has a melting point of 160 ° C.
Those having a temperature in the range of -180 ° C are preferred.

[0010] The slit film of the present invention needs to have a lower melting point than the above-mentioned synthetic fiber yarn and have a light shielding property. This light-shielding film has a light transmittance of 30% or less, particularly a light transmittance of 10%.
The following are preferred. Further, the wavelength is 380 μm to 420
It is desirable that the UV cut ratio of μm is 70% or more, particularly 90% or more. When the light transmittance exceeds 30%,
When the net-shaped knitted fabric is used outdoors, the synthetic fiber yarns are lightly degraded with time due to sunlight, and the strength retention is reduced.
Further, even when the ultraviolet ray cut rate is less than 70%, similar light deterioration occurs, and the strength retention rate decreases.

In the present invention, the synthetic fiber yarn is covered by spirally winding a slit film. In this case, the synthetic fiber yarn is completely covered so that the synthetic fiber yarn does not come out on the surface, and furthermore, the slit film is formed. It is important that the synthetic fiber yarns remain on the surface even after the film is melted. When the synthetic fiber yarn is exposed, the exposed synthetic fiber yarn is lightly degraded over time by sunlight, corroded by alkali, acid, etc. in the soil, and corroded by the action of microorganisms. Retention decreases.

The coated yarn obtained by covering the above-mentioned synthetic fiber yarn with a slit-like film preferably has a denier per yarn within the range of 2,000 to 10,000 denier. If the denier per thread is less than 2000 denier, the tensile strength as a fiber material for civil engineering is insufficient, and if the denier per thread exceeds 10,000 denier, the production becomes extremely difficult. The weight ratio between the synthetic fiber yarn and the slit film is 80:20 to 50: 5.
A range of 0 is desirable. If the weight ratio of the synthetic fiber yarns exceeds 80%, the covering effect by the slit-shaped film becomes insufficient, and if the weight ratio of the synthetic fiber yarns is less than 50%, the coating material increases and is not economical. .

The width of the slit film is 3 to 15 mm.
, Particularly within the range of 5 to 15 mm. If the width of the slit-like film is less than 5 mm, it is difficult to completely cover the synthetic fiber yarn.
If it exceeds mm, it becomes difficult to pass the slit film through a guide or the like of a covering machine used for winding a synthetic fiber yarn.

The coated yarns composed of the synthetic fiber yarns and the slit-like film are drawn together and have a warp density of 40 to 400 yarns / m and a weft density of 40 to 400 yarns as in the prior art.
m, and the obtained coarse base cloth is woven at a temperature of 7.
The slit-shaped film located on the surface of the warp and the weft is melted by heating with a heating roller or an infrared heater at 0 to 200 ° C., and the intersection of the warp and the weft is bonded.

[0015]

The coarse base fabric is woven by using a coated yarn obtained by covering a relatively high melting point synthetic fiber yarn with a relatively low melting point slit film as a warp and a weft. At the intersection, the slit films forming the respective surfaces of the warp and the weft are in contact with each other. Therefore, when the coarse base fabric is heated to melt the slit film, the slit film adheres to the synthetic fiber yarns constituting the core yarns of the warp and the weft to form a molten coating layer. At the same time, the warp and the weft are adhered at the intersection of the two and integrated.

When the obtained net-shaped knitted fabric is used for improving soft ground or reinforcing embankment, the synthetic fiber yarn of the core yarn is covered with a molten coating layer of a slit-like film having light-shielding properties. Therefore, the synthetic fiber yarn is not degraded by sunlight, attacked by alkali or acid in soil, or corroded by microorganisms.

[0017]

The present invention will be specifically described below with reference to examples. (Example 1) As shown in FIG. 1, a 3000 denier polyester multifilament yarn (melting point: 255 ° C.) was used for a relatively high melting point synthetic fiber yarn 1 and a relatively low melting point slit-like film 2 was used. 9mm, light transmittance 28%
Using a polyethylene film (melting point 132 ° C.), a slit film 2 is spirally wound around the synthetic fiber yarn 1 to completely cover the synthetic fiber yarn 1, and the total fineness is 4500.
I made denier yarn 3.

Two of the yarns 3 are drawn to 9000 denier, and the drawn yarns are used for the warp 4 and the weft 5, as shown in FIG. 2, and the warp density is 112 / m and the weft density is 108. / M plain weave fabric, and the base fabric is heated by a hot cylinder under the fusing condition of 165 ° C. × 30 seconds to melt the slit film 2 covering the warp yarns 4 and the weft yarns 5, and And a relatively uniform net-like woven fabric 6 having an average size of 7.9 mm x 8.3 mm.
I got

Next, the adhesive strength at the intersection of the warp and the weft was measured using the net-like woven fabric 6. As shown by a chain line in FIG. 2, one warp 4 is gripped by a chuck 7, and net-like woven fabrics 6 on both sides of the warp 4 are gripped by chucks 8, respectively. The required force was measured. However, randomly select 20 intersections,
The adhesive strength at each point was measured, and the average adhesive strength and the variation (R
= Maximum adhesive strength-minimum adhesive strength). as a result,
The average adhesive strength was 6 kg / piece, and the variation R was 0.5 kg.

Further, this woven fabric 6 was cut into a size of 30 cm × 30 cm, and a light resistance test and a chemical resistance test were performed to evaluate the strength retention. The light resistance test was performed under the test conditions of 83 ° C. × 1000 hours, and the chemical resistance test was performed according to JIS K6.
An alkali resistance test based on the 773 method was performed. The strength retention was determined by taking out a warp and a weft from the samples before and after the light resistance test and the chemical resistance test, respectively, and performing a tensile test using a tensile tester under the conditions of a sample length of 20 cm and a tensile speed of 20 cm / min. The strength retention (%) was calculated as (tensile strength of sample after test / tensile strength of sample before test) ×
Calculated by 100. As a result, no decrease in tensile strength was observed in any of the light resistance test and the chemical resistance test, and the strength retention was 100%.

Example 2 The same procedure as in Example 1 was carried out except that a polyethylene film having a width of 6 mm and a light transmittance of 10% was used as the low-melting point slit film 2, and the average size of the mesh was 8%. A relatively uniform net-like woven fabric 6 of 0.2 mm × 8.5 mm was obtained. Then, in the same manner as in Example 1,
When the adhesive strength at the intersection of the warp and the weft was measured, the result was that the average adhesive strength was 5.8 kg and the variation R was 0.4 kg. Further, a light resistance test and a chemical resistance test were performed in the same manner as in Example 1 to determine the strength retention, and no decrease in tensile strength was observed in any of the light resistance test and the chemical resistance test. The strength retention was 100%.

(Comparative Example 1) The same procedure as in Example 1 was repeated except that a polyethylene film (melting point: 132 ° C) having a width of 6 mm and a light transmittance of 45% was used as the slit film 2 having a low melting point. The average size is 8.2 mm x 8.
A relatively uniform 5 mm net-like woven fabric 6 was obtained. Next, the adhesive strength at the intersection of the warp and the weft was measured in the same manner as in Example 1. As a result, the average adhesive strength was 5.9 kg, and the variation R was 0.3 kg. Further, a light resistance test and a chemical resistance test were carried out in the same manner as in Example 1 to determine a strength retention. The chemical resistance test showed no decrease in tensile strength, and the strength retention was 100%. However, since the light transmittance of the slit film was excessive, the tensile strength was significantly reduced in the light resistance test, and the strength retention was 65%.

(Comparative Example 2) The average size of the mesh was 8.4 mm in the same manner as in Example 1 except that a polyethylene film having a width of 3 mm and a light transmittance of 25% was used as the low melting point slit film 2. A relatively uniform net-shaped woven fabric 6 of 8.8 mm was obtained. However, since the width of the slit film 2 was narrow, the coating was incomplete and the synthetic fiber yarn 1 of the core yarn was partially exposed. In this woven fabric, when the adhesive strength at the intersection of the warp and the weft was measured in the same manner as in Example 1, the average of the adhesive strength was reduced to 3.8 kg, and the variation R was 2.5.
kg. Further, a light resistance test and a chemical resistance test were carried out in the same manner as in Example 1 to determine the strength retention. In both the light resistance test and the chemical resistance test, a decrease in tensile strength was observed. Was 73% in the light resistance test and 65% in the chemical resistance test.

(Comparative Example 3) A net-like woven fabric of Comparative Example 3 was manufactured by the method using the bundled yarns of two kinds of synthetic fibers having different melting points described in the above prior art. That is, a 3000 denier polyester multifilament yarn is used as the high melting point fiber, and a 150 denier is used as the low melting point fiber.
Using a 0 denier polyolefin sliver, these were bundled to form a bundled yarn of 4500 denier, and two 9000 denier aligned yarns obtained by aligning the two yarns were used for warp and weft, respectively. A woven fabric having the same structure and density as in Example 1 is woven and heated under the conditions of 140 ° C. × 60 seconds, the intersection of the warp and the weft is heat-fused, and the average size of the mesh is 8.3 mm × 8.7 mm. A net uniform woven fabric 6 was obtained.

Next, the adhesive strength at the intersection of the warp and the weft was measured in the same manner as in Example 1. As a result, the average adhesive strength was 4.3 kg, and the variation R was 1.7 kg. Further, a light resistance test and a chemical resistance test were carried out in the same manner as in Example 1 to determine the strength retention. In both the light resistance test and the chemical resistance test, a decrease in tensile strength was observed. Was 75% in the light resistance test and 55% in the chemical resistance test.

(Comparative Example 4) A net-like woven fabric of Comparative Example 4 was produced by the coating method described in the prior art. That is, two polyester multifilament yarns of 4500 denier were aligned and the obtained 9000 denier aligned yarns were used for warp and weft, respectively, and woven in the same manner as in Example 1. Is impregnated, dried and the average size is 8.2 mm x
An 8.5 mm net-shaped woven fabric 6 was obtained.

The net-shaped woven fabric 6 was curved in appearance, had a noticeable variation in size, and had a poor appearance. When the adhesive strength at the intersection of the warp and the weft was measured in the same manner as in Example 1, the average adhesive strength was 6.3 kg, but the variation R was large and 1.9 kg. In addition, when a light resistance test and a chemical resistance test were performed in the same manner as in Example 1 to determine the strength retention, no decrease in tensile strength was observed in both the light resistance test and the chemical resistance test.
The strength retention was 100%.

[0028]

According to the present invention, there is provided a net-shaped knitted woven fabric using a coated yarn obtained by covering a relatively high-melting synthetic fiber yarn with a relatively low-melting light-shielding slit film as a warp and a weft. Is a method of fusing the slit-shaped film and heat-fusing the intersections of the warp and the weft, so that the net has a large adhesive strength at the intersection of the warp and the weft, and has a uniform appearance and a good appearance. A woven knitted fabric is obtained. In addition, since the synthetic fiber yarn which bears the tensile strength of the net-shaped knitted fabric is covered with a slit-shaped film having light-shielding properties, it is not affected by chemicals such as sunlight, acids, alkalis, etc. The above-mentioned net-shaped knitted fabric is suitable for reinforcing the embankment and improving soft ground.

[Brief description of the drawings]

FIG. 1 is a front view of a coated yarn composed of a synthetic fiber yarn and a slit film.

FIG. 2 is a plan view of a net-like woven fabric.

[Explanation of symbols]

 1: relatively high melting point synthetic fiber yarn 2: relatively low melting point slit film 3: coated yarn 4: warp 5: weft 6: net-like fabric 6 7: chuck 8: chuck

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI D03D 15/00 D03D 15/00 GZ (56) References JP-A-62-250243 (JP, A) JP-A-2-229263 (JP, A) JP-A-2-258657 (JP, A) JP-A-57-147291 (JP, U) JP-A-50-24873 (JP, U) JP-B-38-21845 (JP, B1) 40-31742 (JP, Y1) 10-17448 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06C 3/00-29/00 D03D 1/00- 27/18 D02G 1/00-3/48

Claims (1)

(57) [Claims] 1. A synthetic fiber yarn is completely covered with a slit film having a lower melting point than that of the synthetic fiber yarn and having a light-shielding property, and the obtained coated yarn is used for a warp and a weft. By knitting or weaving in a lattice form to form a coarse base cloth, and then fusing the slit film, the warp and weft of the base cloth are fused and integrated at the intersection of both. Method for producing net-shaped knitted fabric