JPH06123068A - Production of waterproofing coated fabric having water vapor permeability - Google Patents

Abstract

PURPOSE:To obtain the subject fabric having excellent hydraulic pressure resistance and water vapor permeability by coating fabric with a solution of a synthetic polymer consisting essentially of a polyurethane containing a specific amount of silicon dioxide fine powder having specified particle diameters or smaller plural times. CONSTITUTION:A solution of a synthetic polymer consisting essentially of a polyurethane having uniformly dispersed 1wt.% or more nonporous silicon dioxide fine powder having 0.1mum or smaller average particle diameter is applied to fabric of fibers such as synthetic fibers and coagulated by a wet method to form a porous resin layer. Then, the similar resin solution is used and applied to the resin layer of the abric in the same way and a porous resin layer is formed to give a coated fabric having 1kg/cm<2> or higher hydraulic pressure resistance and 6,000g/m<2>24 hours or higher water vapor permeability, provided with both waterproofing performance and water vapor transmission. Before the resin solution is applied, the fabric is preferably subjected to water-repellent processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a moisture-permeable waterproof coated cloth having excellent waterproof and moisture-permeable properties.

[0002]

2. Description of the Related Art Conventionally, coating methods include a wet coating method and a dry coating method. Since the resin for wet coating usually uses N.N'-dimethylformamide as a main solvent, it has low volatility. For this reason, compared with a dry coating resin that uses methyl ethyl ketone, toluene, ethyl acetate, etc. as a main solvent, there is a problem that resin leakage is likely to occur on the surface of the base cloth, that is, the back surface of the coating during coating.

In order to prevent this resin leakage, the base fabric used for coating is densified, water-repellent is applied,
In addition, although measures are taken to crush the base cloth by calendering, it is difficult to completely prevent resin leakage, and the usable base cloth is often a limited base cloth.

When the fiber diameter of the base fabric used is large (for example, a woven fabric having a nylon filament of 200 denier or more), even if calendering is performed, the base fabric has a strong unevenness and poor smoothness. In order to completely form a resin film by the coating process described above, thick coating must be applied, and even if the resin is coated by thick coating, the water resistance of the resulting coated fabric tends to be insufficient.

On the other hand, as a resin for wet coating,
In general, polyurethane resin is most often used, and usually anionic surfactants, nonionic surfactants, hydrophilic polymers, etc. are used together to improve water vapor transmission rate.
Since it is a thick coating, the water vapor transmission rate obtained by one coating is less than 6000 g / m ² · 24 h, which is not sufficient. Especially when coating a heavy-weight fabric, the water vapor transmission rate is 2000 to 5000 g / Not only does it drop significantly below m ² · 24 h, but the water pressure resistance is at most 0.3 to 0.
At present, it has only a performance of about 4 kg / cm ² .

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a moisture-permeable waterproof coating fabric having both excellent waterproof performance and moisture-permeable performance. It is a thing.

[0007]

SUMMARY OF THE INVENTION The present invention achieves the above object and has the following configuration. That is, according to the present invention, a polyurethane polymer-based synthetic polymer solution containing 1% by weight or more of silicon dioxide fine powder having substantially no pores and an average particle size of 0.1 μm or less is applied onto a fiber cloth, A first step of forming a resin layer having a hole by wet film formation,
1.0 kg / cm, which comprises a second step of applying the above-mentioned polyurethane polymer-based synthetic polymer solution again onto the resin layer, and similarly performing wet film formation to form a perforated resin layer.
^A gist of the present invention is a method for producing a moisture-permeable waterproof coating fabric having a water pressure resistance of ² or more and a moisture permeability of 6000 g / m ² · 24 h or more.

The present invention will be described in detail below.

The feature of the method for producing a coated fabric in the present invention is that a fine powder of silicon dioxide is uniformly dispersed and applied in a polar organic solvent solution of a synthetic polymer mainly composed of a polyurethane resin, and then immersed in water to form a resin film. To form,
The so-called wet coating method is performed twice, without impairing the waterproof performance originally possessed by the synthetic polymer mainly composed of polyurethane resin on the fiber cloth as the base cloth.
This is where two fine moisture-permeable resin layers with a large number of holes are formed.

The two wet coating processes in the present invention differ depending on the smoothness and air permeability of the base cloth, but the first time, the dry resin film weight is 15 g / m ² or less, preferably 8 g / m ² or less. In order to obtain sufficient water pressure resistance, in the second time, the coating amount is adjusted so that the dry resin film weight is 10 g / m ² or more in order to obtain sufficient water pressure resistance. It is good to do it. When the resin layer is formed by the first coating and then the second coating is performed on the resin layer, N · N′-dimethylformamide, which is the main solvent of the polyurethane resin, dissolves the first porous resin layer. However, it is difficult for the dissolved portion to become porous at the time of re-solidification, and as a result, a large decrease in moisture permeability is caused, so the amount of resin applied for the first time must be reduced as much as possible.

As described above, in the method of the present invention, a fine powder of silicon dioxide is uniformly dispersed and applied in a polar organic solvent solution of a synthetic polymer mainly composed of polyurethane resin and then immersed in water to form a resin film. The so-called wet coating method is used to form the resin film twice, and the substantially non-porous silicon dioxide fine powder used here is generally a gas phase oxidation method of silicon halide, a combustion hydrolysis method of silicon halide, It is a silicon dioxide fine powder obtained by a dry method such as an electric arc method. The fine powder obtained by the above method has many silanol groups on the particle surface like other general silicon dioxide fine powders. Therefore, it is a hydrophilic substance. In the present invention, silicon dioxide fine powder having a large number of silanol groups on the particle surface has sufficient effect, but this hydrophilic silicon dioxide fine powder is uniformly dispersed in a polyurethane polymer-based synthetic polymer solution. Since the viscosity of the resin solution tends to be strong thixotropic, and water is also easily adsorbed, it is necessary to be careful in coating operation, and the obtained resin film is hydrophilized, which may cause some leakage from the viewpoint of water leakage. Cause the disadvantage of.

In order to make up for these drawbacks, silicon dioxide fine powder is used in the above fine powder to make the fine particle surface hydrophobic by reacting with silanol groups with a substance such as trimethylchlorosilane, dimethyldichlorosilane, ethyl alcohol, isopropyl alcohol. It is effective to use this hydrophobic fine powder, because it does not become so thixotropic and the amount of adsorbed water is small, the stability of the substance itself is excellent, and it is advantageous in operation.

The fine powder used in the present invention may be mainly fine powder of silicon dioxide, and may contain aluminum oxide, magnesium oxide, etc., general fillers, pigments, etc. as impurities or a mixture. There is no problem even if it is done.

The silicon dioxide fine powder used in the present invention is
It means one containing 60% or more as a silicon dioxide component. The fine powder used has an average particle size of 0.1 μm.
It is necessary to be below, and if it is 0.05 μm or less, it is more preferable in terms of effects. If it is larger than 0.1 μm, the pore size of the fine pores of the moisture permeable membrane of the obtained coated fabric becomes too large, and the waterproof performance is deteriorated, which is not preferable.

Further, it is necessary that the silicon dioxide fine powder is uniformly contained in the resin layer composed of a synthetic polymer mainly composed of polyurethane resin in an amount of 1% or more, and more preferably 3% or more. When it is less than 1%, the number of fine pores of the moisture permeable membrane of the obtained coated fabric is small, and high moisture permeability cannot be obtained.

The fiber cloth used in the present invention includes polyamide synthetic fibers represented by nylon 6 and nylon 66, polyester synthetic fibers represented by polyethylene terephthalate, polyacrylonitrile synthetic fibers,
Woven and knitted fabrics made of polyvinyl alcohol synthetic fibers, semi-synthetic fibers such as triacetate, or mixed fibers such as nylon 6 / cotton, polyethylene terephthalate / cotton, etc.
Nonwoven fabrics and the like can be mentioned.

In the present invention, the above-mentioned fiber cloth treated with a water repellent may be used. This is one means for preventing the penetration of the resin solution into the fabric. In this case, the water repellent may be a known one such as a paraffin water repellent, a polysiloxane water repellent, or a fluorine water repellent, and the treatment thereof is also a commonly used padding method, spray method, or the like. The known method may be used. When particularly good water repellency is required, a fluorine-based water repellent is used. For example, Asahi Guard 730 (Asahi Glass Co., Ltd., fluorine-based water repellent emulsion) is padded with a 5% aqueous dispersion ( Aperture ratio 3
5%), and then heat treatment at 160 ° C. for 1 minute.

In the coated cloth of the present invention, a solution of a synthetic polymer mainly composed of a polyurethane resin containing a fine powder of silicon dioxide is applied onto the above-mentioned fiber cloth by a wet coating method. The term "polyurethane resin-based synthetic polymer" as used herein means one containing 50 to 100% of a polyurethane component, and other synthetic polymers include, for example, polyacrylic acid, polyvinyl chloride, polystyrene, polybutadiene, polyamino acid, etc. Or a copolymer thereof or the like may be contained in a range of less than 50%. Of course, a compound modified with fluorine, silicon or the like can be used in the present invention.

Polyurethane resin is a copolymer obtained by reacting polyisocyanate and polyol,
As the isocyanate component, aromatic diisocyanate,
An aliphatic diisocyanate and an alicyclic diisocyanate may be used alone or in a mixture thereof.
2,4-diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,6-hexane diisocyanate, 1,
4-cyclohexane diisocyanate, etc.,
Polyether polyol or polyester polyol is used as the polyol component, polyethylene glycol, polypropylene glycol, polytetramethylene glycol or the like is used as the polyether polyol, and diol such as ethylene glycol or propylene glycol and adipic acid or sebacine is used as the polyester polyol. 2 such as acid
A reaction product with a basic acid or a ring-opening polymer such as caprolactone is used.

The polyurethane polymer-based synthetic polymer solution containing fine particles of silicon dioxide may be appropriately applied by a usual coating method, for example, a knife coater, a comma coater, a reverse coater, etc. The knife coater is suitable for the resin coating amount, but is not particularly limited.

In the present invention, for the purpose of improving the peel resistance between the resin layer and the fiber cloth and between the resin layers, a compound having a high affinity for the resin and the fiber cloth may be used in combination. It is good to use together. As the isocyanate compound, 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or a compound containing 3 mol of these diisocyanates and active hydrogen (eg, trimethylolpropane,
Triisocyanates obtained by addition reaction with 1 mol of glycerin etc. can be used. The above isocyanates may be in a form in which the isocyanate group is free, or in a form in which the block is dissociated by the subsequent heat treatment after being stabilized by adding phenol, methylethylketoxime, or the like. However, it can be used, and it may be properly used depending on workability and purpose.

The amount of the isocyanate compound used is preferably 0.1 to 10% by weight based on the synthetic polymer mainly composed of the polyurethane resin.
If the amount used is less than 0.1%, the adhesive force of the resin layer to the fabric is low, and if it exceeds 10%, the texture tends to harden, which is not preferable.

In the present invention, the resin solution consisting of the above-mentioned polyurethane-based synthetic polymer is coated on the fiber cloth for the first time and then immersed in water at 0 to 30 ° C. for 0.5 to 10 minutes to remove the resin content. Wet coagulation. Hereinafter, after washing in warm water of 40 to 60 ° C. for 5 to 15 minutes, it is dried by a usual method,
After the second coating, a resin film is formed by the same method as above.

In the present invention, for the purpose of further improving waterproofness, the coated fabric may be subjected to water repellent treatment after wet coating. For the water repellent treatment, the well-known water repellent treatment method that is generally carried out as described above may be adopted. Further, when it is desired to further improve the waterproof performance, a dry film thickness of 0.5 on the wet coating layer of the present invention.
A non-porous polyurethane resin layer or the like having a thickness of about 2 μm may be formed. Since the wet coating layer has high water pressure resistance, the waterproof performance is synergistically improved even with a thin film, and the moisture permeability is not significantly reduced.

[0025]

[Working] A synthetic polymer solution composed mainly of polyurethane resin, in which fine particles of silicon dioxide having an average particle diameter of 0.1 μm or less are substantially dispersed, is coated on a cloth and wet coagulated to obtain a polyurethane resin. Forms a peculiar porous structure, and at the same time finely disperses the silicon dioxide fine powder in the solution, there is a slight difference in the solidification rate at the interface between the silicon dioxide fine powder and the resin to be solidified. As a result, it becomes possible to form a large number of fine pores of 1 μm or less that significantly improve the moisture permeability without lowering the waterproof performance.

When such a wet coating is performed thinly in the first time mainly on the concave portions on the surface of the base cloth, the coating resin penetrates into the fiber gaps on the surface of the base cloth, but does not reach the back surface of the base cloth. Therefore, not only the adhesive strength between the base cloth and the resin film is improved, but also the appearance of the base cloth is improved. When the second wet coating is performed in such a state, the affinity between the resins is good because of the same resin. , It is possible to form a coating resin layer having a predetermined performance and film thickness without causing a problem in adhesive strength.

In the present invention, since the moisture permeation performance is improved due to the formed fine perforations, the water leakage characteristic of a highly moisture-permeable and waterproof fabric is likely to occur when pressure is applied during wearing. It is also very effective. Furthermore, since the silicon dioxide fine powder of the present invention is evenly present from the surface layer to the lower layer of the resin layer, the surface of the resin layer eliminates the slimy feeling peculiar to the polyurethane resin and gives a dry touch, and at the same time the entire resin layer is Wear resistance and resin film strength are improved.

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The performance of the coated fabrics in the examples was measured by the following method. (1) Water pressure resistance: JIS L-1092 (high water pressure method) (2) Moisture vapor transmission rate: JIS L-1099 (A-1 method) (3) Resin leakage: Visual observation of resin leakage to the base fabric surface did. (4) Water leakage: Bundesmann method (JIS L-10
According to the reference test method of No. 92), the amount of water leakage after 120 minutes was measured, and the state of the resin film surface due to water penetration was visually observed. (5) Abrasion strength: JIS L-1084 (A-1
Method) (6) Peel strength: A hot melt tape was adhered to the coating surface in the longitudinal direction, and the measurement was performed according to JIS L-1089 method.

Example 1 Nylon high multifilament 7 for both warp and weft
Warp density 11 using 0 denier / 68 filament
Weaving a plain weave with 0 yarns / inch and weft density of 80 yarns / inch, and scouring and dyeing in the usual way (Diacid Light Yellow 2GP 1% owf, acid dye manufactured by Mitsubishi Kasei Co., Ltd.)
After that, padding (40% squeezing ratio) with a 3% aqueous solution of Asahi Guard 710 (manufactured by Asahi Glass Co., Ltd.) of a fluorine-based water repellent emulsion was performed, followed by drying and then heat treatment at 160 ° C. for 1 minute. Next, using a calendering machine with a mirror surface roll, temperature 170 ° C, pressure 30 kg / cm ² , speed 30
Calendering was performed under the condition of m / min to obtain a base fabric for coating.

Here, as the first step, the following prescription 1
24% solids concentration, viscosity 15000CP /
The polyurethane resin solution at 25 ° C. was applied to the calender surface of the above base cloth using a knife over roll coater in an amount of 25
After coating at g / m ^2, it was immediately immersed in water at 15 ° C. for 30 seconds to solidify the resin component, followed by washing in warm water at 50 ° C. for 5 minutes and drying.

Formulation 1 Resamine CU-4550 100 parts (Dainichi Seika Kogyo Co., Ltd., ester type polyurethane resin) Resamine X-100 1 part (Dainichi Seika Kogyo Co., Ltd., isocyanate compound) NN-dimethylformamide 30 Part Aerosil R-974 3 parts (Nippon Aerosil Co., Ltd., hydrophobic silicon dioxide fine powder with an average particle size of 0.012 μm)

Next, in the second step, a polyurethane resin solution having the same formulation 1 was applied to the above coated surface at a coating amount of 80 g / m ² using a knife over roll coater,
Immediately soak in water at 15 ° C for 60 seconds to solidify the resin component, then wash for 10 minutes in warm water at 50 ° C and dry to obtain a resin layer containing 11% of silicon dioxide fine powder (dry resin). A moisture-permeable waterproof coating fabric of the present invention having a coating weight of about 25 g / m ² ) was obtained.

For comparison with the present invention, a moisture-permeable waterproof coating fabric for comparison (comparative example 1 and comparative example 1) was prepared in the same manner as in this example except that Aerosil R-974 was omitted from formulation 1 in this example. I will).

For comparison with the present invention, the same coating solution was applied to the calender surface of the above-mentioned base cloth in the present example, instead of applying the resin solution of Formulation 2 twice, in an amount of 105 g / m ²
A coated fabric for comparison (referred to as Comparative Example 2) was obtained by the same method as that of this example except that the coating was performed once.

The performances of the present invention and the comparative coated fabric were measured and evaluated, and the results are shown together in Table 1.

[0036]

[Table 1]

As is clear from Table 1, the moisture-permeable and waterproof coating fabric produced by the method of the present invention has no resin leakage onto the surface of the base fabric, has excellent water pressure resistance and moisture permeability, and has water leakage and resistance. It can be seen that the peelability and wear resistance are also good.

Example 2 A plain woven fabric having a nylon yarn 210 denier / 36 filament for both warp and weft and having a warp density of 65 yarns / inch and a weft yarn density of 50 yarns / inch was woven. A base fabric for coating was obtained by the method. Next, except that the same amount of Aerosil # 200 (manufactured by Nippon Aerosil Co., Ltd., hydrophilic silicon dioxide fine powder having an average particle size of 0.012 μm) was used in place of Aerosil R-974 in Formulation 1 of Example 1 above, The moisture-permeable and waterproof coated fabric of the present invention was produced by the same method as in Example 1.

For comparison with the present invention, a coated cloth for comparison (referred to as Comparative Example 3) was prepared in the same manner as in this Example except that Aerosil # 200 was omitted from the coating resin liquid formulation in this Example. Got

For comparison with the present invention, instead of applying the resin solution twice to the calender surface of the base fabric in this example, the same application solution is applied once at an application amount of 105 g / m ² . Otherwise, a moisture-permeable and waterproof coating fabric for comparison (referred to as Comparative Example 4) was obtained by the same method as in this example.

The performances of the present invention and the comparative coated fabrics were measured and evaluated, and the results are shown together in Table 2.

[0042]

[Table 2]

As is clear from Table 2, the moisture-permeable and waterproof coating fabric produced by the method of the present invention has no resin leakage onto the surface of the base fabric, has excellent water pressure resistance and moisture permeability, and has peeling resistance, It can be seen that the wear resistance is also good.

[0044]

According to the method of the present invention, it is possible to produce a moisture-permeable and waterproof coating fabric having excellent water pressure resistance and moisture permeability. Further, the coated fabric of the present invention is excellent in peeling resistance and abrasion resistance of the coating resin layer. According to the method of the present invention, a thin coating is applied in the first wet coating process, and therefore it is effective for the base fabric which is apt to cause resin leakage to the surface of the base fabric, which is very advantageous in the coating operation. The coated fabric of the present invention is a material suitable for apparel such as rainwear and outerwear because of its excellent performance.

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Claims (1)

[Claims] 1. A synthetic polymer solution mainly composed of polyurethane resin containing 1% by weight or more of silicon dioxide fine powder having substantially no pores and an average particle size of 0.1 μm or less is coated on a fiber cloth, and then wet. A first step of forming a film to form a perforated resin layer,
1.0 kg / cm, which comprises a second step of applying the above-mentioned polyurethane polymer-based synthetic polymer solution again onto the resin layer, and similarly performing wet film formation to form a perforated resin layer.
^A method for producing a moisture-permeable waterproof coated fabric having a water pressure resistance of ² or more and a moisture permeability of 6000 g / m ² · 24 h or more.