JP2000233460A - Condensationproof, waterproof and lightproof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a sheet, which is equipped with a waterproofness and a lightproofness, prevents dropwise condensation from developing and makes recyclable by a method wherein a reversibly humidity absorbable and releasable fiber hygroscopic woven fabric and a waterproof and lightproof layer are laminated onto each other. SOLUTION: A reversibly humidity absorbable and releasable hygroscopic woven fabric 2 and a waterproof and ligthtproof layer 3 are laminated to each other. As the hygroscopic woven fabric 2, polyolefin multifilaments, which are easily fiber formable and low in cost, are preferable and especially, polypropylene multifilaments excellent in mechanical characteristics are preferable. As the waterproof and lightproof layer 3, a polyolefin layer equipped with a waterproofness and a polyolefin layer including colored pigments having a lightproofness are preferable. As the colored pigments, light reflective pigments such as white ones, silver ones or the like and/or light absorbent pigments such as black ones or the like are employed. Or, the waterproof and lightproof layer 3 is produced by forming a polyolefin layer 5 through are extrusion laminating method for a propylene-ethylene random copolymer added with metallic aluminum powder on the surface of a polyolefin layer 4 equipped with waterproofness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet having a dew condensation preventing property, a waterproof property and a light shielding property.

[0002]

2. Description of the Related Art Conventionally, sheets such as cargo sheets such as trucks and outdoor covers such as agricultural products are required to have a light-shielding property in the daytime and a waterproof property in the case of rainy weather, as well as a dew-condensing property. It had been. This is because a waterproof layer is provided to impart waterproofness, and the air containing moisture inside covered with the waterproof layer does not ventilate with the outside,
Dew condensation on the inside of the seat due to temperature drop at night etc.
This is because there is a problem that the coating is damaged by the dew water.

In order to improve the dew condensation preventing property, a sheet obtained by integrating a water-absorbing polymer into a sheet is often used. However, a sheet using a water-absorbing polymer has a large water absorption per unit area. The water that has once absorbed water is strongly bonded to the water-absorbing polymer by chemical bonding or the like with the water-absorbing polymer. I had to dispose everything.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a waterproof property and a light-shielding property, and can prevent dew condensation due to a decrease in temperature by absorbing moisture. It is an object of the present invention to provide a dew-preventing waterproof light-shielding sheet which can be reversibly released and dried to regenerate.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a structure in which a moisture-absorbent woven knitted fabric made of fiber capable of reversibly absorbing and releasing moisture and a waterproof light-shielding layer are laminated. The above problem is solved by providing a dew condensation preventing waterproof light-shielding sheet characterized by the following.

[0006] The moisture-absorbing woven or knitted fabric is preferably a woven or knitted fabric composed of polyolefinic multifilaments, and the waterproof light-shielding layer is preferably a polyolefin layer containing a light-shielding colored pigment.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The moisture-absorbent woven knitted fabric made of fibers capable of reversibly absorbing and releasing moisture according to the present invention is a woven knitted fabric obtained by weaving and knitting using fibers as weft yarns. The bond is not due to a chemical bond or the like, but is a bond due to affinity, and moisture absorption and release can be easily performed reversibly. As this moisture-absorbing woven knitted fabric, specifically, a woven or knitted fabric having hygroscopicity due to water permeation based on a capillary phenomenon into a fiber gap of a hydrophobic synthetic fiber woven or knitted fabric, or a hydrophilic natural fiber or synthetic fiber It is a woven or knitted fabric or felt formed using fibers. Among these, a woven knitted fabric made of a synthetic fiber woven knitted fabric is preferable.

The woven knitted fabric made of the hydrophobic synthetic fiber woven knitted fabric is a woven knitted fabric formed by weaving and knitting multifilaments made of polyolefin such as polyethylene and polypropylene, polyester, polyamide and the like. Of these, polyolefin multifilaments that are easy to form fibers and are inexpensive are preferable, and polypropylene multifilaments excellent in mechanical properties are particularly preferable.

The multifilament preferably has a single yarn fineness of 0.1 to 20 denier (hereinafter abbreviated as d), more preferably 0.5 to 10 d. Single yarn fineness is 0.1d
If it is less than 20%, the fiber-forming property is difficult. Further, the total fineness is preferably from 200 to 3000 d, more preferably from 300 to 1500 d. The multifilament may be subjected to a surfactant treatment.

The above-mentioned multifilament is woven and knitted using a warp and / or a weft to form a hygroscopic woven knitted fabric.
As the moisture-absorbing woven or knitted fabric, multifilaments may be used alone, but filaments having other yarn forms may be mixed by twisting, interlacing, interlacing, interlacing or the like. When filaments having other yarn forms are mixed, the use ratio of the multifilament is preferably at least 50% by weight. As a specific example of the mixing, there is a plain woven fabric using a polypropylene flat yarn as a warp and a polypropylene multifilament as a weft.

The natural fibers having hydrophilicity include cotton spun yarn, silk spun yarn, wool spun yarn and rayon spun yarn, and the hydrophilic synthetic fibers include fibers made of polyacrylonitrile, polyvinyl alcohol and the like. No. Of these, cotton spun yarn is preferred from the viewpoint of water retention, low cost, and the like. Examples of the felt include a woven felt and a compressed felt made of a natural fiber, and a needle felt obtained by needle punching a web made of short fibers.

[0012] The synthetic fiber and the natural fiber are intertwisted, interwoven,
Mixing by mixing and knitting is acceptable.

The basis weight of the hygroscopic woven or knitted fabric is 50 to 500 g /
m ² is preferable, 100 to 300 g / ^{m 2} is more preferable.

The waterproof light-shielding layer of the present invention is a layer in which a water-resistant polyolefin layer contains a coloring pigment having a light-shielding property, or a layer in which an aluminum layer is laminated on a polyolefin layer. Among these, a polyolefin layer containing a coloring pigment is preferable.

The coloring pigment is not particularly limited, but a light-reflective pigment such as white or silver and / or a light-absorbing pigment such as black is used. The content of the coloring pigment is preferably from 0.1 to 5% by weight, more preferably from 0.5 to 2% by weight. When the light-reflective pigment and the light-absorbing pigment are used in combination, it is preferable to use the polyolefin layer containing the light-reflective pigment on the surface layer and the polyolefin layer containing the light-absorbing pigment on the back layer. preferable.

The method for providing the aluminum layer is not particularly limited, and a method in which an aluminum vapor-deposited film or aluminum foil and a polyolefin layer are laminated by a sandwich lamination method can be used.

The waterproofing light-shielding sheet for preventing condensation of the present invention is formed by laminating the above-mentioned moisture-absorbent woven knitted fabric and a waterproof light-shielding layer. As a lamination method, a hygroscopic woven knitted fabric and a previously formed polyolefin film may be laminated using an adhesive or the like, but a method of providing a polyolefin layer on one surface of the hygroscopic woven knitted fabric by a known extrusion lamination method is used. preferable. As a method for containing a light-shielding colored pigment in the polyolefin layer, a polyolefin containing the colored pigment may be laminated by an extrusion laminating method. An aluminum vapor-deposited layer may be provided on a polyolefin layer laminated on one side by an extrusion laminating method by a known aluminum vapor-depositing method.

In the present invention, a woven or knitted fabric sheet for reinforcement may be laminated and used as necessary. The reinforcing woven or knitted fabric sheet is a woven fabric obtained by using thermoplastic resin fibers as warp yarns. As the thermoplastic resin, nylon, polyester, polyolefin, and the like having excellent fiber-forming properties are used.Polyolefin excellent in moldability and inexpensiveness is suitably used, and particularly, polypropylene which is lightweight and has high strength is preferable. . As the fiber form, any of monofilaments, multifilaments obtained by bundling low fineness monofilaments, tape-shaped flat yarns, split yarns obtained by subjecting flat yarns to splitting, and the like can be formed by a known molding method. Among these, a flat yarn which is flexible and has excellent laminate forming properties is preferable.

The reinforcing woven / knitted fabric sheet is used interposed between the moisture-absorbing woven / knitted fabric and the waterproof light-shielding layer. /
It has a configuration of an adhesive laminate layer / a hygroscopic woven knitted fabric.

The thermoplastic resin used in the present invention includes an antioxidant, a lubricant, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent, a pigment within a range not departing from the gist of the present invention depending on the purpose of use. Further, additives such as an inorganic filler, an organic filler, a crosslinking agent, a foaming agent, and a nucleating agent may be blended.

The dew-preventing waterproof light-shielding sheet obtained as described above is cut into a predetermined size and a predetermined shape, subjected to edging and the like, and if necessary, punched with eyelets, etc. It is suitably used for cover sheets and the like.

[0022]

EXAMPLES Polypropylene (MFR = 20 g / 10 mi)
n, density = 0.90 g / cm ³ , Tm = 158.0 ° C.) to form a multifilament having a total fineness of 680 d / 120 f. Using this polypropylene multifilament as the warp yarn, a plain-woven hygroscopic woven knitted fabric 2 having a driving density of 20 × 20 yarns / inch was obtained. The basis weight of the hygroscopic woven knitted fabric 2 was about 125 g / m ² . A propylene-ethylene random copolymer (MFR)
= 20.0 g / 10 min., Density = 0.90 g / c
m ³ ), 0.5% by weight of carbon black was added thereto, and a 50 μm-thick waterproof polyolefin layer 4 was provided by an extrusion lamination method, and the propylene-ethylene random copolymer was coated on the surface of the polyolefin layer 4 with a metal. Addition of 1% by weight of aluminum powder and extrusion lamination
A waterproof light-shielding layer 3 on which a polyolefin layer 5 having a thickness of μm was formed was formed, and a moisture-absorbing woven knitted fabric 2 and a waterproof light-shielding layer 3 were laminated to obtain a dew-prevention waterproof waterproof light-shielding sheet 1. The moisture-absorbing amount of the dew-condensing waterproof light-shielding sheet 1 thus obtained was 80 g / m ^{2. After} absorbing the moisture, the sheet was easily dried by leaving it at 20 ° C. × 40% humidity for 2 hours, and then immediately re-used. It was able to exhibit the initial moisture absorption performance when used.

[0023]

As described above, the present invention has a moisture-absorbing woven knitted fabric made of a fiber capable of reversibly absorbing and releasing moisture and a waterproof light-shielding layer, thereby having a dew condensation preventing property and a waterproof light-shielding property. This is a light-weight, high-strength, dew-proof, waterproof, light-shielding sheet that can easily re-use moisture that has absorbed moisture by drying. This dew-preventing waterproof light-shielding sheet can be suitably used as a load sheet for trucks and the like, and a sheet for outdoor covers of agricultural products and the like.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a dew condensation preventing waterproof light-shielding sheet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waterproof light-shielding sheet with dew condensation prevention property 2 Woven woven knitted fabric 3 Waterproof light-shielding layer 4 Carbon black-containing polyolefin layer 5 Metal aluminum-containing polyolefin layer

Claims (3)

[Claims] An anti-condensation-resistant waterproof light-shielding sheet comprising a layer of a moisture-absorbent woven knitted fabric made of fiber capable of reversibly absorbing and releasing moisture and a waterproof light-shielding layer. 2. The dewatering-preventing waterproof light-shielding sheet according to claim 1, wherein the moisture-absorbing woven knitted fabric is a woven knitted fabric composed of polyolefinic multifilaments. 3. The waterproofing light-shielding sheet according to claim 1, wherein the waterproof light-shielding layer is a polyolefin layer containing a light-shielding colored pigment.