JPH07113193B2 - Method of manufacturing breathable waterproof cloth - 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 of manufacturing a breathable waterproof cloth .

[0002]

2. Description of the Related Art A breathable waterproof cloth is used as a material for rain clothes, ski wear and the like. In particular, when used as a material for rain clothing, it is generally required that not only waterproofness practically sufficient but also physical properties such as moisture permeability and soft texture.
As a breathable waterproof cloth used for the material for rain clothing,
Rubberized cloth, urethane coated cloth, acrylic coated cloth and the like are known. However, all of these materials have a particularly poor moisture permeability and have a drawback that they are apt to be worn when worn as a raincoat, and the discomfort during wearing is inevitable. After that, for the purpose of improving the moisture permeability, we propose a moisture-permeable waterproof fabric with a structure in which a dry subbing layer made of polyurethane resin and a subbing layer made of polyurethane resin to be wet-coagulated are sequentially laminated on a base fabric such as woven fabric. Has been done. This moisture-permeable waterproof cloth is formed by applying a composition prepared by adding a water-soluble substance (for example, salt, sugar, mirabilite, sodium glutamate, gelatin, etc.) to a polyurethane resin on a base cloth and then drying it to form a coating film (resin). Then, the solution of the polyurethane resin to be wet-coagulated is applied onto the coating film, and then the whole is immersed in water to dissolve and remove the water-soluble substance in the coating film layer, thereby forming a porous film. Is formed, and at the same time, the polyurethane resin of the coating film thereon is wet solidified to form an upper subbing layer, which is produced.

[0003]

However, even the above-mentioned moisture-permeable waterproof cloth in which the undercoat layer and the overcoat layer are provided on the base fabric is not yet satisfactory in moisture permeability, and is made of polyurethane resin. Due to the presence of the dry subbing layer, there is a problem that the texture becomes hard as a whole. Even during its production, since the water-soluble substance is fine particles, it is difficult to uniformly disperse it in the polyurethane resin, and the mixing work for that is complicated and time-consuming. Moreover, since it is difficult to uniformly disperse the water-soluble substance in the resin as described above, the fine pores formed by dissolution and removal of the substance and the distribution of the pores must be non-uniform. , Was inferior in quality stability. The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and provides a breathable waterproof cloth having excellent breathability without impairing physical properties such as waterproofness and texture.
It is an object to provide a manufacturing method for obtaining the same.

[0004]

The method for producing a moisture-permeable waterproof cloth of the present invention has a viscosity of 60,000 to 90,000 at 25 ° C. of a polyurethane resin containing a crosslinking agent on a base cloth.
The water-miscible organic solvent solution with cps was applied so that the application amount was 5 to 15 g / m ^{2 in} terms of resin solid content, and the viscosity of the polyurethane resin at 25 ° C. was further applied to the application surface.
After applying a water-miscible organic solvent solution having a degree of 10,000 to 30,000 cps , it is immersed in water to coagulate the polyurethane resin and then dried by heating to simultaneously form an undercoat layer and an overcoat layer to form a base fabric. It is characterized by being integrated.

The present invention will be described below with reference to the drawings. Figure 1 is manufactured by the method of manufacturing breathable waterproof cloth.
The is a sectional view showing an embodiment of a moisture-permeable waterproof fabric, the lower the moisture-permeable waterproof fabric, basically the base fabric 1 as shown in FIG. 1, is laminated on the base fabric 1 sublayer 2 and the overcoat layer 3. Reference numeral 4 in the drawing denotes a skin layer provided as necessary.
As the base cloth 1, woven cloth, non-woven cloth, woven cloth, or the like can be used, and for example, woven cloth made of nylon fiber can be used. If necessary, the base cloth 1 may be subjected to a water repellent treatment to impart water repellency.

In the production method of the present invention, first, the base fabric 1 as described above is used, and a water having a high viscosity of a polyurethane resin containing a crosslinking agent is used to form an undercoat layer on the base fabric by a flow coater or the like. Apply the miscible organic solvent solution. Then, a water-miscible organic solvent solution having a low viscosity of the polyurethane resin for forming an overcoat layer is continuously applied to the applied surface by a doctor knife coater or the like. The above-mentioned highly viscous solvent solution has a viscosity at 25 ° C of 60000-
It is 90000 cps, and the basis weight (application amount) is 5 to 15 g / m ² in terms of polyurethane resin solid content. On the other hand, the solvent solution having the low viscosity has the same viscosity as the above.
000 to 30,000 cps, and the coating amount is preferably about 30 to 150 g / m ^{2 in the} same conversion. By increasing the viscosity of the solvent solution for forming the undercoat layer,
It is possible to prevent the solvent solution for forming the overcoat layer to be applied thereafter from penetrating into the base cloth. Since the undercoat layer is a thin film having a smaller film thickness than the overcoat layer, the basis weight is within the above numerical range. If the basis weight is less than 5 g / m ² , the sealing effect is small and the peel strength becomes insufficient, and if it exceeds 15 g / m ² , the texture becomes hard, which is not preferable for applications such as clothing.

As the above-mentioned polyurethane resin which constitutes the undercoat layer and the overcoat layer in the present invention, polypropylene glycol type polyurethane, polytetramethylene glycol type polyurethane, polycarbonate type polyurethane, polyester type polyurethane and the like are used.
The 0% modulus is preferably ²⁰ to 100 kg / cm ² . As the water-miscible organic solvent, for example, dimethylformamide (DMF), dimethylacetamide (DMA), tetrahydrofuran (THF), dioxane (DOX), a mixture thereof or the like is used.
The solvent solution of the polyurethane resin may be blended with a cell regulator, a pigment and the like, if necessary.

As the crosslinking agent added to the polyurethane resin for forming the undercoat layer, hexamethylene diisocyanate trimer (HDI), trimethylolpropane (T
Examples thereof include adducts of MP) and tolylene diisocyanate (TDI), adducts of TMP and HDI, adducts of TMP and isophorone diisocyanate (IPDI), and among them, hexamethylene diisocyanate trimer is preferable. This crosslinking agent has a polyurethane resin solid content of 10
Add 0.1 to 10 parts by weight to 0 parts by weight. If the amount of cross-linking agent added is less than this, the undercoat layer and base fabric (and the overcoat layer)
There is a problem that sufficient adhesive strength with and cannot be obtained, and conversely if the amount exceeds the above range, the texture becomes hard. Further, the viscosity adjustment of the solvent solution of the resin, pulp floc, silica,
It is performed by appropriately adding a thickening (increasing) agent such as calcium carbonate. In the case of pulp floc,
10 to 1 for 100 parts by weight of polyurethane resin solids
00 parts by weight is preferred. Especially, when this pulp floc is not added, the water vapor transmission rate (JIS Z 0208) is 10
Although it is about 00 g / m ² · 24 hr, the moisture permeability is 2500 g / m when about 10 parts by weight of pulp floc is added.
^The result is more than 2.24 hours and improved.

When the water-repellent treated base cloth 1 is used, the water-repellent treatment is applied before the coating step. The water repellent treatment can be carried out by a conventionally known treatment method. For example, the base cloth material is dipped in a solution of a water repellent such as fluorine and dried, or the water repellent solution is applied to the surface of the base cloth. Apply and perform. By performing this treatment, not only the waterproof performance of the base cloth can be obtained, but also the coating liquid can be prevented from permeating into the back surface of the base cloth in the step of applying the undercoat layer, and the texture of the base cloth can be softened. You can also Conventionally, since the water-repellent treated base cloth inhibits the adhesion with the resin, the water-repellent treatment is often performed in the final step, but in the present invention, the adhesive strength between the base cloth and the resin is increased by the crosslinking with the crosslinking agent. Therefore, there is an advantage that the water-repellent base cloth can be used from the beginning to manufacture the base cloth.

Next, the base cloth 1 which has been subjected to the above-mentioned coating work.
Is immersed in water and then dried by heating. By this water immersion, the solvent is removed to wet-solidify the polyurethane resin, and in the drying process, crosslinking between the resin and the base cloth is performed by the crosslinking agent. As a result, the undercoating layer 2 and the overcoating layer 3 each of which is a microporous layer in which communicating fine pores are uniformly present are formed at the same time, and a moisture-permeable waterproof cloth integrated with the base cloth is obtained. Here, the moisture-permeable waterproof cloth of the present invention is excellent in peel strength between layers due to the presence of the undercoat layer, which means that the crosslinking agent added to the resin for forming the undercoat layer is It is considered that this is an effect obtained by giving priority to the crosslinking reaction between the resins and the base cloth during the drying step rather than the reaction. That is, crosslinking does not readily occur at the substrate temperature (less than 100 ° C) in the presence of water and at the stage of evaporation of water, and the crosslinking reaction proceeds at the substrate temperature during drying (100 ° C or more). Is. This phenomenon is particularly remarkable when hexamethylene diisocyanate trimer is used as a crosslinking agent. By the way, the peel strength when no crosslinking agent is added is (JIS
L 1092) becomes less than 0.6 kg / 3 cm, while the addition of a crosslinking agent as in the present invention results in 1.5 kg / 3 cm.
The above peel strength can be obtained.

A moisture-permeable waterproof cloth is obtained by the above steps, but if a skin layer 4 is further provided on the overcoat layer 3, it may be formed after this. Although desired physical properties can be additionally imparted by the skin layer 4, the skin layer needs to be at least a layer having moisture permeability. For example, the undercoating layer and the overcoating layer have a cell structure in which they communicate with each other, and have excellent moisture permeability and a very soft texture, but on the other hand, they tend to lack water pressure resistance (water impermeable), so this is covered. A skin layer for can be provided. In that case, it is formed by directly coating a polyurethane resin on the upper coating layer and drying.

The moisture-permeable waterproof cloth produced by the production method of the present invention has a moisture permeability (JIS Z 0208) of 2500 g /
m ² · 24 hr or more, water resistance (JIS L 1092 B method) is 2.0 kgf / cm ² or more, water repellency (JIS
L 1092) is 90 or more, and the peel strength between the base cloth and the wet microporous layer of polyurethane resin is (J
IS L 1092) 1.2 kg / 3 cm or more.

[0013]

【Example】

Example 1 A woven fabric of 210 denier nylon ox is dipped in a 10% aqueous solution of Dickguard (manufactured by Dainippon Ink and Chemicals, Inc.), dried and treated for water repellency. An undercoat layer forming solution (viscosity of 70,000 cps) having the following composition was applied to one side of this woven cloth by a flow coater so that the coating amount was 50 g / wt of the urethane resin solution.
After coating so as to be m ² , subsequently, a coating layer forming solution (viscosity 25,000 cps) having the following composition is applied to the coated surface by a doctor knife coater to give a coating amount of 200 g / m ^{2 in} terms of the same resin solution weight. To apply. “Part” below
Indicates parts by weight. (Undercoat layer forming solution) -Krisbon MP145 (manufactured by Dainippon Ink and Chemicals, 100 parts, polyurethane with 100% modulus of 45 kg / cm) -Silicon additive 1 part-Polypropylene glycol 2 parts-KC Flock W300 (Sanyo Kokusai Pulp) 20 parts Hexamethylene diisocyanate trimer (manufactured by Dainichiseika) 5 parts Pigment 0.5 parts DMF 40 parts (solution for forming an overcoat layer) Crisbon MP145 100 parts Silicone additive 1 part Polypropylene glycol 2 parts-KC Flock W300 10 parts-Pigment 0.5 parts-DMF 40 parts The woven fabric after application is immersed in water at 25 ° C to remove the solvent to solidify the polyurethane, and after dehydration 130 ° C. Dried under hot air. Finally, the resin composition having the following composition is applied with a doctor knife coater so that the coating amount is 50 by weight of the resin solution.
It was applied so as to be g / m ² to form a skin layer and finished to obtain a moisture-permeable waterproof cloth. (Resin composition) -Rezaroid Lu4095 (manufactured by Dainichiseika) 50 parts-Rezaroid Lu4105 mat (manufactured by Dainichiseika) 50 parts-Pigment 20 parts The resulting moisture-permeable waterproof cloth has a moisture vapor transmission rate of 2500 g / m ² .24.
hr, water resistance of 2.0 kgf / cm ² , water repellency of 90 or more,
The texture was also soft. The peel strength between the woven fabric and the upper and lower pulling layers was 1.2 kg / 3 cm. A rain garment was produced using this waterproof cloth, and when it was worn, it was a comfortable material with no stuffiness, no stuffiness, and sufficient practical durability.

Comparative Example 1 A woven fabric of 210 denier nylon ox is dipped in a 10% aqueous solution of Dickguard (manufactured by Dainippon Ink and Chemicals Co., Ltd.) and dried to be water repellent. On this base cloth (woven cloth), the same coating solution for forming an overcoat layer as in Example 1 was applied at a solution weight of 20.
It is applied so as to be 0 g / m ² , then immersed in water to remove the solvent to solidify the polyurethane, and after dehydration, the temperature is 130 °.
It was dried under hot air of C, and finally, the same resin composition as in Example 1 was applied to the surface in the same manner to form a skin layer, and a moisture-permeable waterproof cloth was obtained. The moisture permeable waterproof cloth obtained has a moisture vapor permeability of 2500 g.
/ M ² · 24 hr, water resistance 2.0 kgf / cm ² , water repellency 90, but the urethane solution oozes out on the back of the base fabric and the appearance of the base fabric surface is significantly impaired. It was hard, and the peel strength between the woven fabric and the overcoat layer was 0.4 kg / 3 cm, which was not practical.

[0015]

As described above, the moisture-permeable waterproofing of the present invention
As described above, the moisture-permeable waterproof cloth manufactured by the method for manufacturing a cloth is formed as a thin film layer of a specific basis weight (film thickness), which is made of a wet microporous polyurethane resin in which the undercoat layer is crosslinked with a crosslinking agent. Therefore, excellent moisture permeability can be obtained by the balance with the upper coating layer made of the wet-solidified polyurethane resin. In addition to waterproofness,
The texture is soft and excellent. Furthermore , the present invention
In the method, as both uniform microporous layer an undercoat layer and top coating layer
Can be formed and the quality of the breathable waterproof cloth such as breathability.
It can be stable . Besides, the obtained transparency
The wet waterproof cloth also has excellent peeling strength due to cross-linking between resins by a cross-linking agent and with a base cloth. Thus, the present invention
The method for producing a moisture-permeable waterproof cloth is a moisture-permeable waterproof cloth having excellent moisture permeability, waterproofness, texture, and peel strength as described above, and a manufacturing procedure for forming a polyurethane resin layer for ordinary wet coagulation and It is possible to easily, quickly, and stably manufacture by a method that is not much different from the operation content.

[Brief description of drawings]

FIG. 1 is manufactured by the method of manufacturing a moisture-permeable waterproof cloth of the present invention.
Sectional view showing an embodiment of a moisture-permeable waterproof cloth.

Claims (1)

[Claims] 1. A polyurethane resin containing a cross-linking agent on a base cloth has a viscosity at 25 ° C. of 60,000 to 90,000.
The water-miscible organic solvent solution with cps was applied so that the application amount was 5 to 15 g / m ^{2 in} terms of resin solid content, and the viscosity of the polyurethane resin at 25 ° C. was further applied to the application surface.
After applying a water-miscible organic solvent solution having a degree of 10,000 to 30,000 cps , it is immersed in water to coagulate the polyurethane resin and then dried by heating to simultaneously form an undercoat layer and an overcoat layer to form a base fabric. A method for producing a breathable waterproof cloth, characterized by being integrated.