JP2001293806A - Air permeable laminated sheet and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air permeable laminated sheet comprising lightweight high strength laminated cloth generating no shift of mesh, capable of easily setting and altering air penneability corresponding to a purpose and having light transmissivity and heat insulating properties or shading properties if desired. SOLUTION: The air permeable laminated sheet 1 is obtained by providing a laminate layer 5, which comprises polyolefin and has omitted parts 6 formed thereto in a sea-island state by a foaming extrusion lamination method, on the surface of a texitile fabric 4 comprising polyolefin stretched yarn such as flat yarn 2 or a monofilament 3 formed under a specific stretching condition and suitably used as an agricultural heat insulating or shading sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a breathable laminated sheet and its use. It is suitably used as a heat insulating sheet for agricultural use, a light shielding sheet, and the like.

[0002]

2. Description of the Related Art Conventionally, forcing cultivation in a house (greenhouse) or a tunnel in cultivation of fruits, flowers and the like has been widely performed, and as a covering material for these houses and tunnels, polyvinyl chloride, polyethylene, ethylene- A film or laminate cloth made of a vinyl acetate copolymer or the like is widely used because it has excellent mechanical properties and also has excellent properties such as light transmission and heat retention. However, agricultural houses coated with this type of coating tend to have too large a daytime temperature or humidity rise due to the lack of ventilation of the coating. There was a problem such as sometimes exceeding.

In order to alleviate such rapid changes in temperature, humidity, etc., air-permeable sheets made of synthetic fiber woven or knitted fabric or net fabric are used. It is not preferable to increase the weaving density too much in order to maintain the air permeability, and the filler is not usually filled. As a result, these sheets are misaligned due to stretching work, causing fluctuations in heat retention and light-shielding properties, making it difficult for crops to maintain an appropriate temperature and appropriate light-shielding properties, and sometimes resulting in mechanical properties such as breakage. There is a problem that causes a decrease in

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a lightweight, high-strength laminate cloth which does not cause misalignment.
It is an object of the present invention to provide a gas-permeable laminated sheet having a light-transmitting property, a heat-retaining property, or a light-blocking property as desired, wherein the gas permeability can be easily changed according to the purpose, and a use thereof.

[0005]

Means for Solving the Problems As means for solving the above problems, the breathable laminated sheet of the present invention comprises at least a woven or knitted fabric made of a drawn polyolefin yarn having a tensile strength of 3 cN / dt or more by uniaxial drawing. One side is provided with a laminate layer having a sea-island-shaped defect formed by a foamed extrusion lamination method made of polyolefin.

In the above breathable laminated sheet, the width of the drawn polyolefin yarn used for the warp constituting the woven or knitted fabric is ₁ mm, the width of the drawn polyolefin yarn used for the weft is W ₂ mm, and the driving density of the warp is Is M _{1 /} 2.54c
m, when the implantation density of the weft was _{M 2} present per 2.54 cm, is better to satisfy the following (1) to (3) simultaneously. (1) A = W ₁ × M ₁ ≦ 30 and B = W ₂ × M ₂ ≦
30 (2) A + B ≦ 50 (3) 0.1 ≦ W ₁ and W ₂ ≦ 8

In the above-mentioned air-permeable laminated sheet, one of the warp and the weft constituting the woven or knitted fabric is a polyolefin flat yarn and / or a polyolefin monofilament, and the other is a polyolefin monofilament and / or a polyolefin multifilament. Can be.

[0008] The air-permeable laminated sheet having a structure in which the woven or knitted fabric and the laminate layer have a light-transmitting property can be suitably used as a heat insulating sheet for agriculture using this as a base material.

Further, a breathable laminated sheet having a structure in which carbon black is blended in the woven or knitted fabric and / or the laminate layer can be suitably used as a light-shielding sheet using this as a base material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The breathable laminated sheet of the present invention has a configuration in which a woven or knitted fabric made of a drawn yarn made of polyolefin is provided with a laminate layer made of polyolefin on at least one surface.

Of the above polyolefins, the polyolefin used for the drawn yarn is preferably a polyolefin having a drawing effect and a high strength.
Linear low-density polyethylene, polypropylene, and the like.

As the form of the drawn yarn, monofilaments formed by extruding from a die and subjected to uniaxial drawing, multifilaments obtained by bundling a plurality of monofilaments of low fineness, and a flat film obtained by subjecting a formed film to slitting followed by uniaxial drawing. Any of yarns, split yarns obtained by subjecting flat yarns to splitting treatment, and the like can be used.

It is important that the drawn yarn has a tensile strength of 3 cN / dt or more (centinewton per decitex).
It is preferably cN / dt or more. If the tensile strength is less than 3 cN / dt, the strength is insufficient for the use of the present invention, which is not preferable. The fineness of the drawn yarn is 100-3000 dtex (hereinafter, referred to as
dt) is preferably used.

The stretching method is not particularly limited.
With a device such as a hot plate contact type, a hot roll type, or a hot air oven type, a drawn yarn that has been drawn in one axis direction is formed through a single-stage or multi-stage drawing process. It is important that the stretching ratio is 4 to 12 times, more preferably 6 to 10 times. If the stretching ratio is less than 4 times, the tensile strength becomes insufficient and it becomes difficult to achieve the object of the present invention. If the stretching ratio exceeds 12 times, productivity is lowered due to breakage in stretching and the like, which is not preferable. The stretching treatment is performed at a temperature lower than the melting point of the polyolefin and higher than the softening point. As a heating method, any method such as a hot roll method, a hot plate method, an infrared method, and a hot air method can be adopted. The formula is preferred in terms of stretching efficiency, high-speed productivity, and stability. The formed undrawn yarn is heated and drawn by the peripheral speed difference between the front and rear rolls.

As the weaving structure of the woven or knitted fabric, various structures such as plain weave, twill weave, entangled weave, and mosaic weave are used.
As the knitting structure, warp knitting, weft knitting and the like are appropriately used. The woven or knitted fabric may have a configuration in which monofilaments, multifilaments, flat yarns, split yarns, and the like are independently disposed as warps and / or wefts, or may have a configuration in which two or more types are appropriately combined and interwoven.

In the woven or knitted fabric, the width (or diameter) of the drawn polyolefin yarn used for the warp is W ₁ mm, and the width (or diameter) of the drawn polyolefin yarn used for the weft is W ₂ mm.
And then, the warp of the implantation density _{M 1} present per 2.54 cm, when the implantation density of the weft was _{M 2} present per 2.54 cm, the ventilation of the following (1) to (3) are simultaneously satisfied It is preferable in maintaining the properties. (1) A = W ₁ × M ₁ ≦ 30 and B = W ₂ × M ₂ ≦
30 (2) A + B ≦ 50 (3) 0.1 ≦ W ₁ and W ₂ ≦ 8

By satisfying the expression (1), even though the warp or the weft is almost densely arranged, by satisfying the expression (2), either the warp or the weft is coarsely arranged. That is, a void is formed at the intersection of the warp and the weft to maintain air permeability. The woven knitted fabric having such a configuration is densely woven and knitted and has no voids in plan, but has voids because the warp yarns three-dimensionally intersect with a thickness at intersections of the warp yarns. It covers everything from knitted fabrics to moderately coarse nets.

In the case where a flat yarn or a split yarn of a flat yarn is interwoven with a monofilament or a multifilament of a filament yarn,
Flat yarn width W ₁ mm, filament diameter W ₂ m
m, the warp driving density is ₁ flat yarn M / 2.54 cm,
Filament yarn m _{1 /} 2.54 cm, weft driving density: flat yarn M ₂ / 2.54 cm, filament yarn m ₂ /
When it is set to 2.54 cm, it is preferable that the following expressions (3) to (5) are simultaneously satisfied. (3) 0.1 ≦ W ₁ and W ₂ ≦ 8 (4) C = W ₁ × M ₁ + W ₂ × m ₁ ≦ 30 and D = W
₁ × M ₂ + W ₂ × m ₂ ≦ 30 (5) C + D ≦ 50

A preferable combination of the warp and the weft is such that one of the warp and the weft is a polyolefin flat yarn and / or a polyolefin monofilament, and the other is a polyolefin monofilament and / or a polyolefin multifilament. As an example of a preferable specific configuration, a flat yarn or a split yarn of a flat yarn as a warp is 500 to 3000 dt, and a driving density is 3 to 10 yarns / 2.
54 cm, monofilament or multifilament as weft is 100 to 1500 dt and driving density is 3 to 20
Book / 2.54 cm. The weight of the woven or knitted fabric is 50
Preferably ^{~300g / m 2, 100~200g / m} 2
Is more preferred.

A laminate layer made of polyolefin is provided on both sides of the woven or knitted fabric obtained as described above to form a breathable laminated sheet of the present invention. At this time, a foaming agent is mixed with the polyolefin used for the laminate layer, and the mixture is melt-extruded with an extruder, and the foaming state is adjusted by adjusting the type of the foaming agent, the type of the polyolefin, the extrusion temperature, the processing speed, and the like.
A sea-island-shaped defect controlled to a predetermined size is formed in the molten film extruded from the die, and the molten film is laminated on a woven or knitted fabric to form a laminate layer. The shape of the defective portion is generally circular or elliptical due to the effect of the surface tension of the molten resin. Although the size of the defective portion varies depending on the application, the diameter of the defective portion is preferably about 10 to 50 mm, and the area ratio of the defective portion is preferably 20 to 70% of the whole. Further, the thickness of the laminate layer can be arbitrarily set, but is preferably 30 to 150 μm, and 50 to 100 μm.
Is more preferred.

Examples of the foaming agent include organic foaming agents such as azodicarbonamide, azobisisobutyronitrile, N, N'-dinitrosopentamethylenetetramine, benzenesulfonylhydrazide, and propane, butane, pentane and hexane. Inorganic compounds containing water of crystallization, such as low-boiling hydrocarbons, magnesium hydroxide, and aluminum hydroxide, or water are used. The blending ratio of the foaming agent varies depending on the foaming state for controlling the sea-island-shaped defective portion, but usually 0.1 to 10 parts by weight of the foaming agent is preferable for 100 parts by weight of the polyolefin.

Specific examples of the polyolefin used in the laminate layer include low-density polyethylene, linear low-density polyethylene, an ethylene / α-olefin copolymer produced by a metallocene catalyst, an ethylene-vinyl acetate copolymer, Resins usually used in extrusion lamination methods, such as ethylene-alkyl acrylate copolymers, polypropylene, and propylene-ethylene copolymers, may be mentioned.

Among the air-permeable laminated sheets obtained as described above, those in which a drawn color and / or a transparent colorant is added to a drawn yarn and / or a laminate layer without adding a colorant or the like are suitable. It has excellent air permeability and excellent translucency, and is suitably used as an agricultural heat insulating sheet. The translucency is not only necessary for growing the crop, but also has the advantage that the growth state and the like can be observed from outside the house or the like. At this time, the air permeability can be easily adjusted by adjusting the driving density of the warp yarns of the woven or knitted fabric and controlling the sea-island-shaped defective portion of the laminate layer by adjusting the foaming conditions.

[0024] Of the above-mentioned air-permeable laminated sheets, those obtained by blending a drawn yarn and / or a laminating layer with carbon black have an appropriate air-permeability and excellent light-shielding properties, and are suitably used as light-shielding sheets. . The black colored sheet absorbs heat energy at the same time as shading, so if it is not air-permeable, the inside of a house or the like will become hot and it will be unsuitable for plant growth, so it will have a moderate ventilation as a light-shielding sheet Sex is required.

The polyolefin used in the present invention includes:
Within the scope of the present invention, an antioxidant,
UV absorbers, light stabilizers, lubricants, antistatic agents, antifoggants,
Ordinarily used additives such as a flame retardant, an inorganic filler and a nucleating agent may be blended.

[0026]

As described above, the breathable laminated sheet of the present invention can be obtained by a foam extrusion lamination method comprising a polyolefin drawn yarn uniaxially drawn under specific drawing conditions and at least one surface of a woven or knitted fabric comprising a polyolefin. It is composed of a configuration in which a laminated layer formed by forming a defective portion in a sea-island shape is provided, and the woven and knitted fabric has a moderately breathable property and can be easily laminated by laminating a laminated layer having a defective portion in a sea-island shape It is possible to control the air permeability and to perform the sealing process at the intersections of the warp yarns, so that it is suitably used as a lightweight and high-strength agricultural heat insulating sheet or light shielding sheet.

In particular, when a filament yarn is used as the warp or weft, the filament yarn is thicker than the flat yarn, so that voids are likely to be formed at the intersections of the warp yarns. It has the advantages of being difficult to get stuffy, stuffy, easy to penetrate rainwater and irrigation water, and has a reduced translucent area with the flat yarn used for the warp or weft, increasing the translucency and improving the lighting. There are advantages, such as promoting the development of.

When a multifilament is used for a warp or a weft, when moisture evaporated from the ground surface adheres to the sheet surface, it is difficult for the multifilament surface to become water droplets due to a capillary phenomenon, and the yarn is alternately turned upside down due to the characteristics of the woven fabric. Since they are arranged side by side, the moisture absorbed by the multifilament has an advantage of dew condensation prevention, such as being transferred to the surface and discharged to the outside.

[0029]

EXAMPLES Example 1: High density polyethylene (MFR =
(0.7 g / 10 min, density = 0.957 g / cm ³ ), and was extruded into a film by a T-die method, and was cooled by water cooling to form a film. This film was drawn at a draw ratio of 6 times by a hot plate contact drawing method to form a flat yarn 2 having a fineness of 550 dt, a yarn width of 2.2 mm and a thickness of 0.02 mm. The tensile strength of the flat yarn 2 was 4.2 cN / dt. In addition, high-density polyethylene (MFR = 1.1 g)
/ 10 min, density = 0.951 g / cm ³ ), and stretched at a stretch ratio of 9 times, with a fineness of 330 dt and a diameter of 0.2 m.
m monofilaments 3 were formed. The tensile strength of the monofilament 3 was 5.4 cN / dt. The flat yarn 2 is used for the warp, the monofilament 3 is used for the weft, and the driving density is 10 × 8 / 2.5 as the warp.
4 cm, a plain woven fabric 4 having a basis weight of 33 g / m ² was obtained. At this time, C in the above-described equations (3) to (5)
= 22 <30, D = 1.6 <30, C + D = 23.6 <5
0, which is a configuration capable of maintaining appropriate air permeability. On one side of the woven fabric 4, low-density polyethylene (MFR
= 8.0 g / 10 min, density = 0.917 g / cm ³ )
On the other hand, a composition containing 5.0% by weight of azodicarbonamide as a foaming agent and 3% by weight of a white pigment was overfoamed at an extrusion temperature of 290 ° C. using an extruder to form a sea-island-shaped defect 5
Was extruded, and a laminating layer 6 having a defect 5 with a thickness of 60 μm was formed on one surface of the woven fabric 4 by extrusion lamination to obtain a breathable laminated sheet 1. The diameter of the defective part was 20 mm on average, and the area ratio of the defective part was 50%. The air-permeable laminated sheet obtained in this manner had a suitable air permeability and excellent light-transmitting properties, and was suitably used as an agricultural heat insulating sheet.

Example 2: High density polyethylene (MFR =
0.7 g / 10 min, density = 0.957 g / cm ³ ), and 3% by weight of carbon black.
The film was extruded by a T-die method and cooled by a water cooling method to form a film. This film is drawn at a draw ratio of 6 times by a hot plate contact drawing method, and has a fineness of 1000 dt and a yarn width of 5 m.
m, a flat yarn having a thickness of 0.018 mm was formed.
The tensile strength of this black flat yarn was 4.5 cN / dt. The flat yarn having a fineness of 550 dt used in Example 1 was used as a warp, the black flat yarn having a fineness of 1000 dt was used as a weft, and the driving density was 10 × 3 yarns / warp.
A plain woven fabric having a basis weight of 24 g / m ² was obtained with a width of 2.54 cm. At this time, A = 22 <30, B = 15 <30, A + B = 37 <in the above equations (1) to (3).
50, which is a configuration capable of maintaining appropriate air permeability. On one side of the woven fabric, low density polyethylene (MFR
= 8.0 g / 10 min, density = 0.917 g / cm ³ )
Laminating was performed in the same manner as in Example 1 except that 3% by weight of carbon black was blended. The air-permeable laminated sheet thus obtained had a moderate air-permeability, an excellent light-shielding property with a light-shielding rate of 98%, and was suitably used as a light-shielding sheet.

Example 3 Fineness 550 dt used in Example 1
Flat yarn of warp and polypropylene (MFR
= 20 g / 10 min) using a total fineness of 680.
dt / 120f, 0.3mm diameter multifilament
Tensile strength of 5.2 cN / dt) as weft
10 × 8 yarns / 2.54 cm as yarn, with a basis weight of 4
5g / m ²Was obtained. At this time, the above equation
C = 22 <30, D = 2.4 in (3) to (5)
<30, C + D = 24.4 <50, moderate ventilation
It has a configuration that can maintain the performance. One side of the woven fabric
Lamination was performed in the same manner as in Example 1. Like this
The obtained air-permeable laminated sheet has a moderate air permeability,
Agriculture with excellent translucency and anti-condensing properties
It was suitably used as a thermal insulation sheet.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a breathable laminated sheet according to Example 1 of the present invention.

FIG. 2 is an explanatory diagram illustrating a state of a sea-island-shaped defect in the laminate layer according to FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Breathable laminated sheet 2 Flat yarn 3 Monofilament 4 Woven knitted fabric 5 Laminating layer 6 Missing part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B32B 27/32 B32B 27/32 E D03D 15/00 D03D 15/00 DF term (Reference) 2B024 DA03 DA07 DB02 DB02 DB07 EA01 2B029 EB03 EB08 EB09 EB12 EC02 EC12 4F100 AA37A AA37B AA37C AK03A AK03B AK03C AK05A AK06B AK06C BA02 BA03 BA06 BA10B BA10C BA16 CA01B CA01C CA13B CA13C DG12A DG13A DG17A DJ01B DJ01C EH23 EH23B EH23C EJ37A GB01 JA13A JD02 JK02A JN30 YY00A 4L048 AA15 AB10 AB28 AC09 BA01 BA02 CA11 CA15 DA29

Claims (5)

[Claims] 1. A laminating layer formed by forming a sea-island defective portion on at least one surface of a woven or knitted fabric made of a drawn polyolefin yarn having a tensile strength of 3 cN / dt or more by uniaxial drawing by a foamed extrusion lamination method made of a polyolefin. A breathable laminated sheet provided with. Wherein in the textile fabric, width W ₁ mm polyolefin drawn yarn used in the warp, the width of the polyolefin drawn yarn used in the weft and W ₂ mm, the implantation density of warp M ₁ lines / 2. 54 cm, the density of weft threading is M ₂ pieces / 2.5.
The air-permeable laminated sheet according to claim 1, wherein the following formulas (1) to (3) are satisfied at the same time when the length is 4 cm. (1) A = W ₁ × M ₁ ≦ 30 and B = W ₂ × M ₂ ≦
30 (2) A + B ≦ 50 (3) 0.1 ≦ W ₁ and W ₂ ≦ 8 3. The breathable laminated sheet according to claim 1, wherein one of the warp and the weft is a polyolefin flat yarn and / or a polyolefin monofilament, and the other is a polyolefin monofilament and / or a polyolefin multifilament. . 4. The agricultural heat insulating sheet based on the air-permeable laminated sheet according to claim 1, wherein the woven and knitted fabric and the laminate layer have a light-transmitting property. 5. The light-shielding sheet according to claim 1, wherein carbon black is blended in the woven or knitted fabric and / or the laminate layer.