JPH0397970A - Waterproofing coating cloth having humidity-absorbing and releasing property - Google Patents

Abstract

PURPOSE:To obtain a waterproofing coating cloth having humidity-absorbing and releasing properties exhibiting specific frictional voltage resistance, moisture permeability and resistance to hydraulic pressure with keeping its characteristics even after high degree of washing by forming a film of polyurethane-based resin having specific physical properties on the surface of fibrous base cloth. CONSTITUTION:A film mainly composed of polyurethane resin having characteristics such as water-absorbing property of 0.5-50 times of its own weight, <=50 times volume expansion at maximum water-absorption and <=30min water-releasing property is formed on a surface of fibrous base cloth such as woven and knit fabric, etc., composed of synthetic or natural fiber to afford the aimed waterproofing coating cloth with humidity-absorbing and releasing properties having dewing-preventing property, antistatic property, moisture permeability, waterproofing property and water-repelling property with durability such as >=50min dewing initiating time of the coating layer, <=500V frictional voltage resistance, 2000-8000g/cm<2> 24hr moisture permeability, 500-3000mmH2O resistance to hydraulic pressure and able to keep >=80% of said properties even after 45 times of washing according to JIS L-1042-83 G method.

Description

[Detailed description of the invention] 2. 1. Industrial Application Fields> The present invention has durable anti-condensation and anti-static properties. This invention relates to a moisture absorbing and desorbing waterproof coated fabric that has moisture permeability, waterproofness, and water repellency.

Prior Art Various types of waterproof coated fabrics have been known. For example, waterproof coated fabrics coated with natural rubber, synthetic rubber, or synthetic resin have been put to practical use in products such as waterproof clothing such as raincoats and windbreakers, and waterproof sheets for use in tents, turbolins, truck hoods, cargo seats, etc. There is.

However, in waterproof clothing, the resin skin PLA layer has low moisture permeability, and when the inside of the clothing becomes hot and humid due to discomfort due to stuffiness during serving or sweating, water vapor condenses inside the clothing (hereinafter referred to as condensation). This caused the wearer to noticeably deteriorate the feeling of wearing. As a solution to the discomfort of wearing waterproof clothing due to high internal humidity, for example, there is a high-density fabric that emphasizes breathability and is treated with water repellent treatment, but its water resistance depends on the structure, density, and fineness of the fabric used. It is determined by, but at most 200 to 3
The fabric had an insufficient water repellency of about 20 mm and had no water repellent durability, so it had only temporary waterproof properties and was unsuitable as a practical waterproof fabric.

On the other hand, Japanese Patent Publication No. 60-47954, Publication No. 60-47
955 and Japanese Patent Application Laid-Open No. 182475/1984, etc., a microporous film composed of a synthetic resin film layer mainly composed of polyurethane polymer has many fine pores on its surface and the interior of the film is It has a cavity that communicates with the air, the diameter of the micropores is 5μ or less, and the moisture permeability is 80009/m・2.
Although a fabric is disclosed that has a moisture resistance of 4 hours or less and is waterproof, such fabric is insufficient to prevent condensation of water vapor during sweating, and even though it is a waterproof fabric, the inside of the garment may get wet due to rain. It will be in a similar state.

Furthermore, water repellent treatment is applied to improve waterproofness, but since the entire coated fabric is hydrophobic, it generates strong static electricity, causing damage when worn due to clinging when used or electric shock during discharging. Pleasure increases.

On the other hand, if the diameter of the small pores in the synthetic resin film is made larger and communicated with the inside of the film layer in order to prevent water vapor from filling inside the clothes, this will cause a decrease in waterproofness and/or a decrease in the strength of the resin film layer. The film will break due to abrasion, resulting in poor wearing durability.

On the other hand, waterproof sheets have been made of natural fibers such as cotton, which have been waterproofed with paraffin, metal soap, and the like.

These have the advantage that because the interwoven gaps are not completely blocked by the waterproofing agent, air and moisture will not pass through the interwoven gaps and cause stuffiness or condensation inside. However, the strength of natural fibers is relatively low, and in order to obtain a sufficiently strong sheet, it must be made quite thick, which has the disadvantage of increasing the weight. For this reason, in recent years, synthetic materials with high strength and eaves! IN sheets have come into widespread use. However, in the case of synthetic fiber sheets,
Because it is hydrophobic and lacks water-swellability, conventional cotton sheets have the advantage that when they absorb water, they gradually become wet and can prevent water leakage. Therefore, in order to obtain a sheet that does not allow water to pass through at all, it is necessary to form a skin layer of synthetic resin on the surface of the base fabric. However, in this case, if a tent or a canopy is constructed using a composite IM tarpaulin sheet, dew condensation occurs.

As a solution to this problem, coating a hydrophilic substance on a miscellaneous water-receiving fabric as shown in JP-A No. 56-37370 can be mentioned, but this product is coated with a synthetic resin or rubber, etc. Because it is a waterproof fabric, its moisture permeability is zero or close to zero, making it difficult to release the water vapor that fills the fabric. Further, after the hydrophilic substance absorbs water, the water diffuses into the resin coating vA layer, but the evaporation of condensed water to the outside where humidity is low is blocked by the rubber or synthetic resin coating layer. Therefore, in order to solve this problem, it is necessary to use a hydrophilic substance that has the ability to absorb condensed water, that is, a resin that has a high water absorption capacity.

However, in the case of resins with high water absorption capacity, (1) the force of volumetric expansion is stronger than the force of adhesion to the base fabric or synthetic resin, causing peeling; (2) the time to release absorbed water, that is, the reversible time is long; This results in drawbacks such as difficulty in repeated use.

<Object of the invention> The present invention eliminates the above-mentioned drawbacks and provides excellent dew condensation prevention performance.
The present invention provides a coated fabric that has moisture permeability, antistatic properties, and waterproof properties.

<Structure of the Invention> The structure of the present invention for achieving the above object is as follows.

1. A coated fabric having a synthetic resin film mainly composed of polyurethane resin on at least one side of a fibrous base fabric, with a dew condensation onset time on the coated surface of 50 minutes or more, a frictional charging voltage of 500 V or less, and a moisture permeability of 2000 to 80.
00g/cm2・24 hours, water pressure resistance 500-3000
s port 20, J I 3 1-1042-83
80% of the above performance even after 45 washes according to G method
A moisture-absorbing and desorbing waterproof coated fabric characterized by retaining the following properties.

2. The water absorption performance of polyurethane resin is 0.5 to its own weight.
The moisture absorbing and desorbing waterproof coated fabric according to claim 1, which has a volumetric expansion of 50 times or less at maximum water absorption, and a moisture release performance of 30 minutes or less.

The fibrous base material herein is not particularly limited and may be any material such as synthetic fibers, natural yam, etc., and may also include woven fabrics, knitted fabrics, etc. All types of fabrics, including non-woven fabrics, can be used. Moreover, these mN fabrics are used which have been previously treated with a water repellent. In this case, the old water performance of the fabric is JIS L-1096.
It is desirable that the water repellency is 80 or higher when measured by spraying.

The water repellent used is a paraffin water repellent. A known water repellent such as a polysiloxane water repellent or a fluorine water repellent may be used, and the treatment may be carried out by a commonly known method. However, in order to obtain the durability of water repellency comparable to the high durability of various performances, which is one of the features of the present invention, it is necessary to perform two-step treatment using a combination of a fluorine-based water repellent and melamine resin and a fluorine-based water magic agent. is desirable. For example, after budding in a water repellent bath containing the following formulation, drying is performed at 120°C for 1 minute, and heat treatment is performed at 150°C for 1 minute.

Asahi Guard LS-317 (Asahi Glass ■) 7%
Sumitex Resin M~3 (Sumitomo Chemical ■) 0.5% Sumitex Accelerator ACX (same as above) 0.3% Also, examples of the two-step treatment method for fluorine-based water repellents include Emulsion 3-based fluorine-based Water repellent Asahi Guard A G-71
0 (manufactured by Asahi Glass QM) After treatment with a 5% solution using a known method, the solvent-based fluorine-based water repellent Asahi Guard A G -
610 (manufactured by Asahi Glass viJ) 5 to 7% solution may be used in a known manner. In this case, the treatment with the solvent-based water conditioner may be carried out after the coating treatment with the polyurethane resin.

The basic characteristics that the polyurethane resin used in the present invention should have are (1) water absorption performance of 0.5 to 50 of its own weight (2)
Moisture release performance is 30 minutes or less 4 (3) Volume expansion when absorbing water is 50
It is necessary to have at least double the amount.

That is, as for the film characteristics for absorbing condensed moisture, if the water absorption performance is 0.5 times or less, the condensed moisture cannot be sufficiently absorbed. On the other hand, if the water absorption capacity is 50 times or more, water absorption continues until the water absorption capacity of the coating is reached and moisture release does not begin, resulting in increased volumetric expansion and the coated resin coating peels off from the fabric, making it impossible to put it to practical use.

On the other hand, moisture release performance refers to the ability of absorbed moisture to evaporate as water vapor and return to the state before water absorption, and there are two factors behind this phenomenon.

That is, the absorbed water spreads into the resin film and the water evaporates from the film interface. It is necessary that this depletion rate be within 30 minutes.

If the above speed is slow and there is a large amount of condensed water, the water absorption capacity will be exceeded and no dew condensation prevention effect will be observed.

In addition, the volume of the resin film expands due to the contained moisture, but if the expansion rate exceeds 50 times, the expansion force is greater than the adhesive force between the film and the base material, causing the resin film to separate from the base material. This causes a force-ring phenomenon on the base surface. In addition, since the resin film layer has the above-mentioned performance, it constantly absorbs and releases moisture, and because the resin film retains moisture, the fabric coated with the resin film is D. It also has electric prevention performance. Furthermore, since the resin film is a non-porous film, it depends on the thickness of the film.
It has a waterproof performance of 0 to 5000 am.

A polyurethane resin having the above-mentioned properties is a polymer obtained by reacting a polyisocyanate with a polyol. As the polyisocyanate, known aliphatic and aromatic polyisocyanates can be used, for example,
Hexamethylene diisocyanate], toluene diisocyanate. Mention may be made of xylene diisocyanates and their reaction products with excesses or with excesses of polyhydric alcohols.

As the polyol, known polyols such as polyether or polyester, which are used in the production of ordinary polyurethane resins, can be used. For example, ethylene glycol. diethylene glycol or 1
, 4-butanediol, and a polybasic carboxylic acid such as adivic acid, phthalic acid, or sepatic acid. Examples of the polyether include those obtained by adding one or more alkylene oxides such as ethylene oxide, brobylene oxide, and butylene oxide to ethylene glycol. Furthermore, for the purpose of improving the peeling resistance between the resin film and the fabric, a compound having high affinity with the lI+H base fabric is used in combination with the resin solution. In the present invention, an isocyanate compound is also used as the compound. As an isocyanate compound, 2.4
- Tolylene diisocyanate. Triisocyanates obtained by an addition reaction between 3 moles of diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, or these diisocyanates and 1 mole of a compound containing active hydrogen (for example, trimethylolpropane, glycerin, etc.) used.

The above-mentioned isocyanates may be those in which the isocyanate group is free or phenol. Even if it is stabilized by adding methyl ethyl ketoxime or the like and the blocks are dissociated by subsequent heat treatment, any type can be used, and it may be used appropriately depending on workability, purpose, etc. The amount of isocyanate compound used is 0.1 to 0.1 to the total weight of the polyurethane resin.
It is desirable to use it in a proportion of 10%, preferably 0.5-5%. If the amount is less than 0.1%, the adhesion of the resin to the fabric will be poor, and if it exceeds 10%, the texture will be hardened, which is not preferable.

Of the polyurethane resin mentioned above! The method for coating the fibrous base material may be carried out by a known method.

Kumiura Example> Next, the present invention will be explained in more detail with reference to an example. The performance of the coated fabric in this example was measured and evaluated by the following method.

(1) Condensation start time: The time when water droplets begin to condense on the coated surface when a sample is placed with the coated surface on the high temperature side at the boundary between the outside temperature of 0°C and the water temperature of 25°C.

(2)! ! Friction voltage (V): JIS L-1094-
80B method 20℃. 40%R}-1 (till constant conditions) 0) Moisture permeability: JIS Z-0208 i4) Water pressure resistance: JTS L-1079 (9) Water repellency: JIS L-1092 (6) Washing durability: JIS
L-1042-83 G method Example 1 Polyester taffeta (warp, l#75de polyester filament yarn, warp density x width density of 110 threads/inch and 90 threads/inch, respectively) was scoured and blistered by a known method. Set and dyed. Next, water repellent treatment was performed using a fluorine-based water repellent having the following formulation to obtain a fabric with a water content of 100.

<Water repellent treatment prescription> Asahi Guard LS-317 (Asahi Glass ■) 7.0%
Sumitex Resin M-3 (Sumitomo Chemical ■) 0.5% Sumitex Accelerator-ACX (same as above) 063% Coat the fabric with the polyurethane resin solution shown below using a knife coater and heat at 120°C. It was dried for 2 minutes and heat treated at 150°C for 1 minute. The amount of coated polyurethane resin was 10g/771.

<Coating prescription> Luxkin U Z -264 (Seiko Kasei ■) 1
00 parts Methyl ethyl ketone (MEK) 15 parts The obtained fabric had the properties shown in Table 3.

Example 2 Nylon taffeta (warp and weft 70 de nylon filament yarn, warp density x width density 120 threads/inch x 86 threads/inch) was refined by a known method. Stained. Next, water repellency treatment was performed under the same conditions as in Example 1, resulting in a water repellency of 100.
fabric was obtained. Furthermore, coating was performed using a knife coater using the polyurethane resin solution shown below so that the total wet coating amount was 18 g/Td. Then, the same heat treatment as in Example 1 was performed. Furthermore, in order to improve water repellency and wash resistance, we applied padding with a fluorine-based water repellent using the following formulation.
Drying at 20°C for 2 minutes, 150°C. A heat treatment was carried out for 1 minute to obtain a fabric having the properties shown in Table (3).

<Polyurethane resin composition> Luxkin LJ Z -264 (manufactured by Seiko Kasei ■) 100 parts Dylac White L -1500 (manufactured by Dainippon Ink Chemical ■) 10 parts Methyl ethyl ketone (MFK) 20 parts <Fluorine water repellent composition > Asahi Guard A G-610 (manufactured by Asahi Glass ■) Mineral turpentine 7 parts 100 parts Example 3 Nylon tack (nylon filament thread of warp 70 de, weft 85 de, density of warp x width each 165 pieces / inch x 97 pieces / inch) was dyed by a known method.Then, the same water repellency treatment as in Example 1 was carried out to obtain a fabric with a water repellency of 100.Next, it was coated with a polyurethane resin solution shown below at a rate of 1209/m. The fabric was coated with a knife coater so that the fabric was coated with a knife coater.Next, it was dried for 120'C x 2 minutes and subjected to the same water repellent treatment as in Example 2 to obtain a coated fabric with the properties shown in Table 4.1.

<Polyurethane resin composition> Hookskin IJ Z -265 (manufactured by Seiko Kasei ■) 100 parts Guirac White L -1500 (manufactured by Dainippon Ink Chemical @ J) 10 parts Dylac Black 5179 (same as above) 3 parts M
EK 20 parts Comparative Example 1 Using the same fabric as in Example 1 and a fabric treated with water repellent treatment, coat with the polyurethane resin solution shown below using a knife coater, dry at 120°C for 2 minutes,
Heat treatment was performed at 150'C for 1 minute. The obtained coated fabric was as shown in the front surface.

<Polyurethane resin solution composition> Crysbon 2116-EL (manufactured by Dainippon Ink Chemical ■) 100 parts Crisbon NX (manufactured by Dainippon Ink Chemical ■) 3 parts toluene 20 parts Comparative Example 2 A polyurethane resin solution was prepared as follows in IA2. A coated fabric was obtained in the same manner except that the resin composition was changed to 30 g/d when wet.The properties of the obtained fabric were as shown in Table I, including moisture permeability, Although it had waterproofness and water repellency, it did not have dew condensation performance or υ1 electric performance.

Polyurethane resin composition>
10 parts XOLTEX CL-10 (〃)
3fllM E K
20 parts toluene
10 parts water 4011 Comparative Example 3 A coated fabric was prepared in the same manner as in Example 3 except that the polyurethane solution had the resin composition shown below and the coating output in a wet state was 30 g/d. The properties of the obtained fabric were as shown in the surface finish, and like Comparative Example 2, it did not have dew condensation or electrical training performance.

Kubouriuthalene resin composition> Crisbon N￥T-20 (Dainippon Ink & Chemicals ■)
100 parts isophthalic acid (IPA) 7 parts toluene
7 parts Comparative Example 4 The coated fabric coated and dried in the same manner as in Comparative Example 1 was further coated with polyurethane resin in the same manner as in Example 1. Drying and heat treatment were performed to obtain the coated fabric. The properties of the obtained fabric were as shown in Table I.

Claims (1)

[Scope of Claims] 1. A coated fabric having a synthetic resin film mainly composed of polyurethane resin on at least one side of a fibrous base fabric, wherein the onset time of dew condensation on the coated surface is 50 minutes or more;
Frictional charging voltage is 500V or less, moisture permeability is 2000-800
0g/cm^2・24 hours, water pressure resistance 500-3000
mmH_2O, and retains 80% or more of the above-mentioned performance even after washing 45 times according to the JISL-1042-83G method. 2. The water absorption performance of polyurethane resin is 0.5 to 5 of its own weight.
The moisture absorbing and releasing waterproof coated fabric according to claim 1, which has a volumetric expansion of 0 times and maximum water absorption of 50 times or less, and a moisture release performance of 30 minutes or less.