JPH06200464A - Moisture-permeable-water-proof non-woven sheet - Google Patents

Abstract

PURPOSE:To provide the moisture-permeable.water-proof non-woven sheet having good mechanical physical properties such as tear strength.tensile strength and excellent in functions such as moisture permeability and water-proofness. CONSTITUTION:The moisture-permeable.water-proof non-woven sheet is characterized by having an apparent density of 0.25-0.90g/cm<3> and a moisture permeability of >=2000g/(cm<2>.24hr), and is characterized in that the upper layer of the non-woven sheet comprises hydrophobic thermoplastic synthetic fibers each having a fineness of 0.1-5 denier and the upper layer comprises synthetic fibers each having a fineness of 2-20 denier, plural single filaments being mutually pressed into film-like shapes in the surface layer of the upper layer, and in the next layer, the plural single filaments are tightly adhered to each other, while the shapes of the single filaments are substantially held.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-woven sheet which can be used for building materials, agricultural materials and the like which require moisture permeability and waterproofness.

[0002]

2. Description of the Related Art Recently, a three-dimensional reticulated fiber non-woven sheet such as registered trademark Tyvek (manufactured by DuPont) obtained by a flash spinning method having excellent moisture permeability and waterproofness has been used as a building material for house wraps and the like. There is. However, since the whiteness is high, the back side cannot be seen, and it is difficult to perform “cutter stop work” and the cost is high.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the non-woven sheet when it is used as a building material, etc., which is shown in the prior art, and improves moisture permeability, waterproofness, workability, and economical efficiency. It is intended to provide an excellent nonwoven sheet.

[0004]

The moisture-permeable and waterproof non-woven sheet according to the present invention has an upper layer made of a thermoplastic synthetic fiber having a hydrophobicity of 0.1 to 5 denier and a lower layer having a fineness of 2 to 5.
It is a laminated non-woven sheet made of synthetic fiber of 20 denier, and the upper surface layer is formed by crushing a plurality of monofilaments to each other into a film shape, and the subsequent layer has a substantially monofilament shape. It is characterized in that monofilaments are closely adhered to each other while being kept at an apparent density of 0.25 to 0.90 g / cm ³ , and a moisture permeability of 2000 g / (m ² · 24 hr) or more.

The thermoplastic synthetic fibers having hydrophobicity of the present invention include polyolefin fibers such as polyethylene, polypropylene and ethylene-propylene copolymer, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate and copolymerized polyester, core-sheath type and the like. A single component or a mixed fiber such as a composite fiber. The cross-sectional shape of the constituent fibers is not particularly limited, such as round shape, flat shape, and irregular shape. The fineness of the non-woven sheet forming the upper layer of the present invention is 0.1 to 5
Denier, preferably 0.5 to 3 denier. When the fineness is 0.1 denier or less, the waterproof property is good, but the moisture permeability is low, and there is a problem in strength such as easy breakage. On the other hand, when it is 5 denier or more, the moisture permeability is high,
Water resistance is insufficient. The use of relatively thin fibers as the fibers forming the upper layer of the present invention is effective for obtaining the high waterproofness aimed at by the present invention.

The synthetic fibers forming the lower layer of the present invention include polyolefin fibers such as polyethylene, polypropylene and ethylene-propylene copolymer, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate and copolymerized polyester, nylon 6, nylon 6 and the like.
It is a single component or a mixed fiber such as a polyamide fiber such as No. 6 and a composite fiber such as a core-sheath. The cross-sectional shape of the constituent fibers is not particularly limited, such as round shape, flat shape, and irregular shape. The non-woven sheet forming the lower layer of the present invention has a fineness of 2 to 20 denier, preferably 5 to 15 denier. When the fineness is 2 denier or less, the waterproof property is good, but in terms of physical properties, problems such as easy breakage occur. On the other hand, when it is 20 denier or more, delamination of the laminated surface is likely to occur, and problems such as high waterproofness cannot be obtained. It is effective to use a relatively thick fiber as the fiber forming the lower layer of the present invention in order to obtain a moisture-permeable and waterproof property, which is the object of the present invention, and to obtain a strong non-woven sheet which is not easily broken. is there.

In the non-woven sheet of the present invention, it is necessary to densify the upper surface layer by thermocompression bonding in order to maintain high moisture permeability and high waterproofness. Therefore, the structure of the upper surface layer is such that a plurality of monofilaments are crushed with each other, and when they are crossed with each other, they are buried in each other, and the buried portion and a portion adjacent to each other are flat in a surface contact fusion state. By converting into a film, a smooth film-like layer having a high fiber density is obtained. Then, the subsequent layers are configured such that the degree to which the single fibers are crushed is gradually small and the single fibers are brought into close contact with each other while substantially maintaining the shape of the single fibers, thereby preventing reduction in tear strength and the like. The ratio of the upper layer fiber and the lower layer fiber constituting the nonwoven sheet of the present invention is 20:80 to 80:20.
Is preferred.

The method for producing the nonwoven sheet of the present invention can be obtained by a known method for producing a non-woven fabric. Although not particularly limited, a spunbond method consisting of a bonding step, which is a web forming step in which a molten polymer is sucked and drawn by a high-speed suction gas to open the fiber, and a bonding step is a simple manufacturing method and a low manufacturing cost, It is also a preferable method because it is excellent. Since the fibers constituting the nonwoven fabric of the present invention are required to have functions such as durability, light resistance, water resistance, and flame retardancy for use in building materials and agricultural materials, the purpose of the present invention is An ultraviolet absorber, an antioxidant, an antistatic agent, a pigment, a flame retardant and the like can be added in appropriate amounts within a range that does not impair.

Next, after the web forming step obtained by the above-mentioned method for producing a non-woven sheet, it is passed between a pair of smooth heating rolls for thermocompression bonding or partial thermocompression bonding, and then divided into two stages with a smooth heating roll for heat treatment. Perform crimping. That is, using a device such as a pair of smooth metal rolls, metal rolls and resin rolls, metal rolls and paper rolls, a temperature of 100 ° C. to 24 ° C.
Thermocompression bonding is performed under conditions of 0 ° C. and linear pressure of 5 to 100 kg / cm. Manufacturing conditions are appropriately selected depending on the basis weight and material of the web. In addition, in order to make one side of the nonwoven sheet of the present invention into a film shape and to substantially retain the fiber shape in the subsequent layer, at the time of thermocompression bonding, for example, 5 ° C. or more between the upper roll and the lower roll. It is preferable to provide a temperature difference of (when relatively thin denier is used, it is easy to collapse even at low temperature).

Since the nonwoven sheet of the present invention is obtained under the above production conditions, the apparent density is as high as 0.25 to 0.90 g / cm ³ , and in particular, the surface layer is densified to form a film. High waterproof property is obtained. If the apparent density is 0.25 g / cm ³ or less, the desired waterproofness cannot be obtained, the rigidity becomes insufficient, and the workability deteriorates. On the other hand, when it is 0.90 g / cm ³ or more, the waterproof property and the rigidity are good, but the moisture permeability is insufficient, and the physical properties such as tear strength are deteriorated. Since the nonwoven sheet of the present invention has a moisture permeability of 2000 g / (m ² · 24 hr) or more, problems such as dew condensation do not occur, and the moisture permeability is 2000 g / (m ² · 2).
If it is less than 4 hours, problems such as easy condensation will occur. The breathability of the nonwoven sheet of the present invention is 0.1 cc / cm ² / sec or more, preferably 0.5 to 100 cc / cm ² / sec. Is.

Water resistance of the nonwoven sheet of the present invention is required to be impermeable to water when it rains, and is 50 or more, preferably 70 or more in JIS-L-1092 water repellency test (spray test). It is preferable that the water resistance of Method A is 50 mmH ₂ O or more. The nonwoven sheet of the present invention preferably has a basis weight of 30 to 200 g / m ² . Further, the non-woven sheet of the present invention, depending on the purpose,
Resin processing, water repellent processing, coloring processing, printing processing, vapor deposition processing,
Functionality such as sputtering processing can be improved.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples. The physical properties shown in the examples were measured by the following methods. (1) Water vapor transmission rate; JIS-Z-0280 (40 ° C-RH90%) (2) Waterproofness; JIS-L-1092 Method A (water pressure resistance) and water repellency test (spray test) (3) Breathability; JIS-L-1096 (Fragur method) (4) Tensile strength; JIS-L-1096 (5) Tear strength; JIS-L-1096 D method (Pendulum method) (6) Apparent density; JIS-L-1096 Unit weight And the thickness. (7) Average fiber diameter; 10 or more fiber diameters were read from a magnified photograph of 500 times (scanning electron microscope) and taken as the average value.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.75 was pulled by an air sucker at a melting temperature of 290 ° C. using a rectangular spinneret having a hole diameter of 0.25 mm and the number of holes was 1000, and the discharge amount and the spinning speed were changed. Each of the upper and lower webs was formed and subjected to partial thermocompression bonding using a hot embossing roll having a temperature of 80 ° C. and a projection occupying area ratio of 12% to obtain an intermediate product. Upper web; fineness 1.2 denier. Unit weight 40g / m ^2. Spinning speed 3000m / min Lower layer web; Fineness 6.0 denier. Fabric weight 30g / m ^2. Spinning speed 3000m / min. Next, the intermediate product is subjected to a linear pressure of 80kg / cm using a pair of paper calenders (upper roll 200 ° C metal roll, lower roll 70 ° C paper roll). The non-woven sheet of the present invention was obtained by thermocompression bonding in Table 1. The characteristics are shown in Table 1. From Table 1, the nonwoven sheet of the present invention is a moisture-permeable and waterproof nonwoven sheet having practical properties such as tear strength and excellent in functionality such as moisture permeability and waterproofness.

Example 2 Using a rectangular spinneret having a hole diameter of 0.3 mm and a number of holes of 1000, polypropylene of MFR40 was pulled by air sucker at a melting temperature of 230 ° C., and the discharge amount and the spinning speed were changed to obtain upper and lower layers. Each of the webs was formed and subjected to partial thermocompression bonding using a hot embossing roll having a temperature of 130 ° C. and an occupation area ratio of convex portions of 4% to obtain an intermediate product. Upper layer; fineness of 1.6 denier. Unit weight 40g / m ^2. Spinning speed 4000m / min Lower layer; Fineness 10.0 denier. Unit weight 60g / m ² Spinning speed 3000m / min Next, the intermediate product is a pair of smooth metal rolls, upper roll temperature 180 ℃ / lower roll temperature 120 ℃, linear pressure 35kg / cm
The nonwoven fabric of the present invention was obtained under the conditions described in Table 1 below, and its characteristics are shown in Table 1.

Example 3 Polyester fiber composed of a composite fiber web having an average fineness of 1.8 denier in the upper layer of polyethylene terephthalate and a sheath of polyethylene (weight per unit area: 40 g / m ² ) and a lower layer of polyethylene terephthalate having an average fineness of 5 denier. A laminated web was formed by laminating a web (Basis weight: 40 g / m ² ) and partially thermocompressed using a hot embossing roll having a temperature of 140 ° C. and an occupied area ratio of convex portions of 12% to obtain an intermediate product. Next, a pair of smooth metal rolls was used to obtain the nonwoven fabric of the present invention under the conditions of an upper roll temperature of 135 ° C./a lower roll temperature of 160 ° C. and a linear pressure of 35 kg / cm. The characteristics are shown in Table 1.

[0016] Example -4 polyester staple fibers having a fineness of 1.5d, fiber length 51 mm, and the card web having a basis weight 70 g / m ^2, fineness 15d, fiber length 51
mm, weight 80g / m ² weight of card web is laminated, needle 40,
An intermediate product was obtained under a needle punching condition with a depth of 15 mm and a punching frequency of 120 times / cm ² . (Comparative Example-1) Next, with a pair of smooth metal rolls, the upper roll temperature 22
Thermocompression bonding was performed under the conditions of 5 ° C./lower roll temperature of 235 ° C. and linear pressure of 35 kg / cm. Table 1 shows the characteristics.

Comparative Example-1 The intermediate product of Example-4 before thermocompression bonding was used as a comparative example. Table 1
The characteristics are shown in. From the results of Table 1, the intermediate product which is not subjected to thermocompression bonding has a low apparent density and inferior waterproof property, and does not exhibit the physical properties of the non-woven sheet intended by the present invention.

[0018]

[Table 1]

[0019]

EFFECTS OF THE INVENTION According to the present invention, an inexpensive sheet having excellent moisture permeability and waterproof property, and excellent strength and the like can be obtained since it is obtained by the spunbond method or the like. Therefore, if it is used as a dew condensation prevention sheet in a residential building, the function and characteristics of the non-woven sheet, that is, the moisture permeability and water resistance are good, so it is excellent in preventing rainwater from entering the exterior wall and preventing dew condensation after moving in. A sense of residence can be obtained. Further, since it is a non-woven sheet of the spunbond method, it has the above-mentioned transparency, and as a result, the tacker workability is good. When used as a multi-sheet for fruit trees, root vegetables, etc., it can be used for agricultural materials having effects such as increasing the sugar content without passing rainwater, keeping it warm, and suppressing the growth of weeds.

Claims (1)

[Claims] 1. The upper layer is composed of a thermoplastic synthetic fiber having a hydrophobicity of 0.1 to 5 denier and the lower layer is 2 to 2 in fineness.
A laminated non-woven sheet made of 0 denier synthetic fiber,
In the upper surface layer, a plurality of monofilaments are crushed into each other to form a film, and in the subsequent layer, the monofilaments are adhered to each other while substantially maintaining the shape of the monofilaments, and the apparent density is 0.25 to 0.90 g / cm ³ , moisture permeability of 200
A moisture-permeable and waterproof non-woven sheet characterized by having 0 g / (m ² , 24 hr) or more.