JPH06240582A - Highly moisture-permeable waterproofing material and its production - Google Patents

Abstract

PURPOSE:To obtain the subject material having excellent moisture permeability, waterproofness, stain resistance and abrasion resistance and giving characteristic massive feeling and heavy feeling by forming a coating layer consisting of a polyurethane elastomer composed of a specific component on a surface of a fibrous substrate. CONSTITUTION:A highly moisture-permeable waterproofing material for e.g. a moisture-permeable waterproofing leather-like sheet giving dry feeling, having deep color, high surface strength and little slimy feeling like natural leather is produced by coating a surface of base cloth produced by impregnating a polyurethane elastomer into a fibrous substrate such as woven, knit or nonwoven fabric of synthetic fiber, natural fiber, regenerated fiber, etc., with a coating layer consisting of a polyurethane elastomer polymer produced by reacting a polyurethane having a Brookfield viscometer viscosity of >=150 ps at 25 deg.C in 30wt.% DMF solution and an organic solvent solution (e.g. methyl ethyl ketone or dimethylformamide solution) of a silicone oil containing hydroxyl (terminal) group and having branch bonded through siloxane bond and an aromatic polyisocyanate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a smooth touch feeling on the surface that does not have a slimy feel like natural leather, and has a profound appearance and color depth similar to natural leather. The present invention relates to a highly moisture-permeable waterproof material such as a moisture-permeable waterproof sheet having excellent moisture permeability and waterproof property and excellent surface strength, and a moisture-permeable waterproof leather-like sheet material.

[0002]

2. Description of the Related Art Conventionally, as a moisture-permeable waterproof sheet and a leather-like sheet having excellent moisture permeability, a material that does not pass liquid water such as rainwater even though it allows water vapor to pass through has been demanded. A moisture-permeable waterproof sheet and a leather-like sheet using a stretched and microporous film or a microporous film obtained by wet coagulating a polyurethane resin as a surface coating layer have been proposed. For example, JP-A-61-1744
Japanese Patent Laid-Open No. 80 proposes a highly moisture-permeable and highly waterproof material using a microporous film obtained by wet coagulating a polyurethane resin as a surface coating layer. However, the polyurethane microporous film used here is not water-repellent by itself and therefore requires treatment with a water-repellent agent, which causes problems with durability, and also has stain resistance, abrasion resistance, and surface lubricity. It is also inferior to.

Further, a leather-like sheet using a non-porous film of hydrophilic polyurethane as a surface coating layer instead of a microporous film is disclosed in Japanese Patent Laid-Open No. 271740/1987 and Japanese Patent Laid-Open No. 7-174040.
It is proposed in Japanese Patent Laid-Open No. 192882. All of these leather-like sheets have good moisture permeability and impermeable to liquid water such as rainwater, but since hydrophilic polyurethane is used for the skin layer, the surface swells and loses its shape when wet with water. The appearance was apt to be violated, and all had poor stain resistance, abrasion resistance, and surface slipperiness. A fabric using a non-porous layer of amino acid-modified polyurethane for the skin layer to improve the moisture permeability is proposed in JP-A-1-113230, but the skin layer of the amino acid-modified polyurethane has low surface strength and It must be coated with silicone-modified polyurethane to improve abrasion resistance, and sufficient moisture permeability cannot be obtained.

Further, many leather-like sheets using a polyurethane resin having a siloxane bond as a surface coating layer have been proposed, for example, JP-A-62-206086 and JP-A-1-113230. . These leather-like sheets were excellent in stain resistance, water resistance, abrasion resistance and surface activity due to the siloxane bond introduced into the polyurethane resin, but were unsatisfactory in terms of moisture permeability.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a surface excellent in moisture permeability, waterproofness, stain resistance, abrasion resistance, surface activity and surface strength, in which the above-mentioned drawbacks of the prior art are improved. A breathable waterproof sheet or a breathable waterproof leather that has a smooth texture that does not feel slimy like natural leather and has a deep appearance and color depth similar to natural leather. It is to provide a highly moisture-permeable and waterproof material such as a sheet.

[0006]

According to the present invention, on one surface of a fibrous substrate, a polyurethane having a viscosity of 150 poise or more according to a B type viscosity system of a 30% by weight DMF solution at 25 ° C. and a hydroxyl group having a branch by a siloxane bond is contained. It is a highly moisture-permeable and waterproof material having a polymer coating layer mainly composed of a polyurethane elastic polymer obtained by reacting silicone oil and an aromatic polyisocyanate.

The highly moisture-permeable waterproof material of the present invention comprises a fibrous substrate having a polyurethane having a viscosity of 150 poise or more in a B-type viscosity system at 25 ° C. of a 30 wt% DMF solution,
A composition comprising a hydroxyl group-containing silicone oil having a branch due to a siloxane bond, an aromatic polyisocyanate, and an organic solvent is applied and subjected to a urethanization reaction to form a polymer coating layer, or the composition is a release sheet. It is obtained by applying it on the surface, laminating it on one surface of a fibrous substrate, and subjecting it to a urethanization reaction to form a coating layer of a polyurethane polymer.

[0008]

That is, the highly moisture permeable and waterproof material of the present invention uses, as the coating layer, polyurethane modified with a hydroxyl group-containing silicone oil having a branch by a siloxane bond. The effect of the present invention cannot be obtained when a conventionally used silicone oil having no branch due to a siloxane bond or having a straight chain or an alkyl group as a side chain is used. The hydroxyl group-containing silicone oil having a branch by a siloxane bond of the present invention preferably has a large number of branches by a siloxane bond. If the number of branches due to siloxane bonds increases, an amorphous solid state is likely to be formed. Therefore, it is important to introduce a substituent having a large steric hindrance, such as a phenyl group, into a part of the branches to form a liquid state.

The terminal group of the silicone oil is preferably a hydroxyl group, but may be partially an alkyl group such as a methyl group or an ethyl group. The content of hydroxyl groups in the silicone oil is preferably 200 to 800 in terms of hydroxyl equivalent. If the hydroxyl equivalent is less than 200, the number of bonding points with the organic polyisocyanate is reduced, sufficient film strength cannot be obtained, and the moisture permeability is also reduced. If the hydroxyl equivalent is more than 800, there is no problem in terms of moisture permeability, but reactivity with organic polyisocyanate increases and the urethane reaction proceeds rapidly, so the viscosity of the composition liquid for coating increases in a short time. Since it gels or gels, the process passability becomes poor. Examples of the hydroxyl group-containing silicone oil having a large number of branches by such a siloxane bond include Glycol modified oil: BX16-895 manufactured by Toray Dow Corning Silicone Co., Ltd.

The polyurethane used as a mixture with the hydroxyl group-containing silicone oil in the present invention has a number average molecular weight of 5
00-3000 polymer diol, for example, at least one polymer diol selected from the group of polyester diol, polyether diol, polyester ether diol, polycarbonate diol, polylactone diol and the like, and organic polyisocyanate such as aromatic diamine. A polyurethane obtained by subjecting at least one organic polyisocyanate selected from the group consisting of isocyanate, aromatic triisocyanate, aliphatic diisocyanate and alicyclic diisocyanate to a urethane reaction. If necessary, the polyurethane may be reacted with a low molecular weight compound having at least two active hydrogen atoms such as diol or diamine having a molecular weight of 400 or less as a chain extender.

In the present invention, since the aromatic polyisocyanate reacted with the polyurethane and the hydroxyl group-containing silicone oil has a high urethanization reaction rate, when the coating composition liquid is prepared by diluting it with an organic solvent, the composition liquid can be obtained in a short time. Is likely to cause viscosity increase and gelation. In particular, a prepolymer polyurethane having a low solution viscosity, which is generally used in a two-component polyurethane, has a large viscosity increase of the composition liquid and cannot be used on an industrial scale as it is. Therefore,
The polyurethane used in the present invention is a polyurethane having a low reactivity and a high solution viscosity, which has not been generally used as a prepolymer polyurethane, specifically, a B-type viscosity of a 30% dimethylformamide solution at 25 ° C. It is necessary to use polyurethane having a total viscosity of 150 poise or more.

The 100% modulus of the polyurethane is
20 to 150 kg / cm ² is preferable. When the 100% modulus is large, the texture of the obtained highly moisture-permeable waterproof material becomes hard, and especially when it is made into a leather-like sheet, it has a rough texture and lacks a high-class feel. On the other hand, if the 100% modulus is small, the film strength when used as a coating layer is weak,
The surface strength of the resulting highly moisture-permeable and waterproof material is reduced.

The terminal group of the polyurethane may be a hydroxyl group-terminated one obtained by reacting in an excess hydroxyl group system, or may be one end-capped with a terminal-blocking agent. In the case of an end-capped polyurethane, the urethanization reaction with silicone oil and organic polyisocyanate is considered to react with a part of the urethane bond by an alohanate bond. Further, the terminal group of polyurethane may be one having an isocyanate terminal obtained by reacting with an excess system of isocyanate. In the case of an isocyanate terminal, an aromatic isocyanate terminal has a high reaction rate and tends to cause viscosity increase or gelation in a short time when the composition liquid for coating is used. It is preferably an alicyclic isocyanate.

The weight ratio of the hydroxyl group-containing silicone oil and polyurethane to be mixed is 1: 5 to 6: 5, preferably 2: 5 to 4: 5. When the amount of the silicone oil is large, the moisture permeability and the water resistance are improved, but the surface strength of the coating layer is lowered and the feeling of stickiness is not preferable. On the other hand, when the amount of silicone oil added is small, the sticky feeling is lost, but sufficient moisture permeability cannot be obtained.

The aromatic polyisocyanate to be reacted with the hydroxyl group-containing silicone oil having a branch due to a polyurethane and a siloxane bond may be a diisocyanate or triisocyanate simple substance, but these isocyanates and monomers It is preferable to use adaact polyisocyanate which is obtained by a partial addition reaction with the polyol. The amount of polyisocyanate used with respect to the total amount of polyurethane and silicone oil varies depending on the contents of the hydroxyl group and the isocyanate group of each, but it is almost equivalent, and the weight ratio is 6: 1.
A guideline is ~ 11: 1.

The above-mentioned polyurethane, hydroxyl group-containing silicone oil having a branch by a siloxane bond, and organic polyisocyanate are dissolved in an organic solvent to form a coating layer of the highly moisture-permeable and waterproof material of the present invention. Use the composition liquid. The organic solvent used for preparing the composition liquid for coating in the present invention includes methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone,
Methyl acetate, ethyl acetate, acetone, cyclohexane,
Tetrahydrofuran, methanol, ethanol, dimethylformamide, hexane, benzene, petroleum ether,
Examples include chloroform, toluene, perchlorethylene and the like.

The coating composition liquid is filled with a coloring agent such as a dye or a pigment, a stabilizer, an antistatic agent, a smoothing agent, or an inorganic material such as those used in ordinary synthetic leather or artificial leather, depending on the purpose. Various additives such as agents, hiding agents, softening agents, flame retardants, antioxidants, ultraviolet absorbers, dyes, surfactants, coagulation regulators and lubricants can be added.

As the fibrous substrate used in the present invention, conventionally known polyamides and polyesters are used depending on the use of a highly moisture-permeable waterproof material, that is, a moisture-permeable waterproof sheet for clothing or waterproof leather-like sheet. , Synthetic fibers such as vinylon and polyacrylonitrile, artificial fibers such as rayon, cupra and acetate, or knitted fabrics, woven fabrics and non-woven fabrics obtained from natural fibers such as silk, cotton, wool and hemp, and mainly polyurethane. Any of base fabrics containing an elastic polymer and the like can be used.

Above all, the average single fineness of three-dimensional entanglement is 0.1
A non-woven fabric composed of an ultrafine fiber bundle having a denier or less is preferably used. In particular, in the case of a waterproof leather-like sheet, the entangled nonwoven fabric is impregnated with an elastic polymer mainly composed of polyurethane, and the weight ratio of the ultrafine fiber bundle and the elastic polymer mainly composed of polyurethane is 70/30 to 97 /. A wet fiber sheet having an apparent density of 3 and an apparent density of 0.4 to 0.8 g / cm ³ is more preferable. The fibrous sheet may be one in which a porous layer of an elastic polymer mainly containing polyurethane is laminated on the surface forming the coating layer.

The coating layer is formed on the surface of the fibrous substrate by a roll coating method using a gravure roll or the like, a spray coating method,
The coating composition liquid is directly applied by a direct coating method using a doctor knife or the like, or the coating composition liquid is applied to the surface of a releasable sheet such as release paper and appropriately dried and then adhered to the surface of the fibrous substrate. It can be performed by a conventionally known method such as a transfer method. Care must be taken in coating so that the coating is substantially non-porous.
If the film is intermittent or has an opening, it is difficult to obtain sufficient surface strength and the waterproof property is poor. Therefore, in the present invention, a spray coating method, a direct coating method using a doctor knife, or a transfer method using a release paper is preferable. The coating amount is preferably 20 to 60 μm as the film thickness after drying and curing. When the film thickness of the coating layer is less than 20 μm, it is difficult to obtain sufficient film strength, and when it is more than 60 μm, the moisture permeability is likely to decrease.

The coating layer formed on the surface of the fibrous substrate by coating or transfer method evaporates and removes the solvent and then heat-treated to promote the urethanization reaction. The conditions of the heat treatment are not particularly limited, but usually, the heat treatment is carried out until the isocyanate group is substantially eliminated.
It is about 24 to 36 hours at 0 ° C. After the urethanization reaction is completed, remove the release sheet and use a highly moisture-permeable waterproof material such as waterproof cloth or waterproof leather-like sheet. If the release sheet is peeled off before the urethanization reaction progresses sufficiently, the surface texture pattern tends to become unclear. In addition, the embossing treatment in the case of the direct coating method is performed before the urethane reaction is completed.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, parts and% relate to weight unless otherwise specified.

Example 1 As a fibrous substrate, 20% of a polybutylene adipate-based polyurethane in which a blue colorant was added to an entangled nonwoven fabric of ultrafine fiber-generating fibers containing polyethylene terephthalate as a dispersion component and polyethylene as a dispersion medium component Leather containing polyurethane in a porous state in the entangled nonwoven fabric of ultrafine fiber bundle fibers obtained by impregnating with a dimethylformamide (DMF) solution, coagulating in a 40% DMF aqueous solution, and then dissolving and removing polyethylene with a solvent The base fabric for the sheet was prepared.

As the composition liquid 1 for coating, the following composition was prepared, 70 g / m ^{2 was} coated on a release paper having a grain pattern, dried at 100 ° C. for 2 minutes, and then the same composition liquid 7 was added.
0 g / m ^{2 was} applied and adhered to the above fibrous substrate, dried at 100 ° C. for 3 minutes, cured at 60 ° C. for 48 hours, and then the release paper was peeled off to obtain a leather-like sheet.

Composition of Composition Liquid 1: Polytetramethylene glycol polyurethane (30% solution) 100 parts (viscosity at 25 ° C .: 480 poise) Silicone oil BX16-895 (manufactured by Toray Dow) 16 parts Adduct Polyisocyanate 10 .8 parts (Thrylene diisocyanate 3 equivalents reacted with trimethylolpropane) Carbon black black pigment dispersion liquid (manufactured by Dainichiseika) 10 parts Methyl ethyl ketone 25 parts Dimethylformamide 25 parts

The obtained leather-like sheet has a water vapor transmission rate of 180.
In 0g / m ² / 24hr, surface strength, surface feel, color depth were both good. Further, when a men's shoe is manufactured from the leather-like sheet, the surface of the shoe is not easily scratched, and it has excellent moisture permeability and is comfortable to wear.

Examples 2 to 4 and Comparative Examples 1 to 4 The same as in Example 1 except that the amount of silicone oil added to the coating composition liquid and the coating amount of the composition liquid were changed to those shown in Table 1. A leather-like sheet was obtained. However, the silicone oil used in Comparative Example 4 was a linear hydroxyl group-terminated silicone oil. The performance of the obtained leather-like sheet is also shown in Table 1. Comparative Examples 1 and 2 to which silicone oil was not added or whose addition amount was small
Was inferior in surface strength and moisture permeability. In Comparative Example 4 using the linear silicone oil, the surface strength was excellent, but the moisture permeability was poor.

[0028]

[Table 1] The amount of silicone oil added is the ratio to the solid polyurethane content. The water vapor transmission rate is according to the method of JIS K6549. Linear silicone oil is used as the silicone oil of Comparative Example 4.

Comparative Example 5 In Example 1, the viscosity of the 30% solution at 25 ° C. was 4
Instead of 80 poise polytetramethylene glycol polyurethane, the viscosity of a 30% solution at 25 ° C was 10
A leather-like sheet was processed in the same manner except that poise polybutylene adipate polyurethane was used. Since the composition liquid has a high reaction rate of urethanization, the viscosity of the composition liquid increased every moment during the coating operation, and it was difficult to form a uniform coating layer.

Example 5 In Example 1, as the composition liquid 2 for coating, the following composition was prepared, and 70 g was prepared on a release paper having a grain pattern.
/ M ^{2 and then} dried at 100 ° C. for 2 minutes, and then 70 g / m ^{2 of the} same composition liquid is further applied to adhere to the above fibrous substrate.
After drying at 0 ° C. for 3 minutes, curing was performed at 60 ° C. for 48 hours, and then the release paper was peeled off to obtain a leather-like sheet.

Composition of composition liquid 2: Polyamino acid polyurethane (20% solution) 100 parts (viscosity of 30% solution at 25 ° C .: 530 poise) Silicone oil BX16-895 (Toray Dow) 11 parts Adduct Polyisocyanate Nato 6 parts (Trimethylolpropane reacted with 3 equivalents of tolylene diisocyanate) Carbon black type black pigment dispersion (manufactured by Dainichiseika) 7 parts Methyl ethyl ketone 17 parts Dimethylformamide 17 parts

The obtained leather-like sheet has a water vapor transmission rate of 180.
In 0g / m ² / 24hr, surface strength, surface feel, color depth were both good. Further, when a men's shoe is manufactured from the leather-like sheet, the surface of the shoe is not easily scratched, and it has excellent moisture permeability and is comfortable to wear.

Example 6 As a fibrous substrate, a polybutylene adipate-based polyurethane 16 in which a blue colorant was added to an entangled nonwoven fabric of ultrafine fiber-generating fibers containing nylon-6 as a dispersion component and polyethylene as a dispersion medium component % DMF solution, 50% DM
A base cloth for a leather-like sheet was prepared in which polyurethane was contained in a porous state in an entangled nonwoven fabric of ultrafine fiber bundle-shaped fibers obtained by dissolving and removing polyethylene with a solvent after coagulation in an F aqueous solution.

As the composition liquid 3 for coating, the following composition was prepared, 150 g / m ^{2 was} applied to the base fabric by the direct coating method, dried at 100 ° C. for 2 minutes, and then embossed to give a texture. A leather-like sheet was obtained.

Composition of composition liquid 3: Polyamino acid polyurethane (11% solution) 100 parts (viscosity of 30% solution at 25 ° C .: 1200 poise) Silicone oil BX16-895 (manufactured by Toray Dow) 15 parts Adduct Polyisocyanate Naat 7 parts (Trimethylol propane reacted with 3 equivalents of tolylene diisocyanate) Carbon black black pigment dispersion (manufactured by Dainichiseika) 8 parts Methyl ethyl ketone 17 parts Dimethylformamide 17 parts

The leather-like sheet obtained has a moisture permeability of 200.
In 0g / m ² / 24hr, surface strength, surface feel, color depth were both good. Also, when gloves are made from the leather-like sheet,
The surface strength was good, the moisture permeability was excellent, and the wearing feeling was excellent.

Example 7 The composition liquid 3 of Example 6 was applied to a release paper at 70 g / m ² and 1
After drying at 00 ° C for 2 minutes, 50 g / m ^{2 of the} same composition solution was further added.
Apply and adhere to the surface of a polyester two-weight tricot, dry at 100 ° C for 3 minutes, and then at 60 ° C for 48 minutes.
After curing for a period of time, the release paper was peeled off to obtain a waterproof sheet. The resulting tarpaulin texture flexible, moisture permeability there 3000g / m ² / 24hr, waterproof was sewn windbreaker was excellent as moisture-permeable both good wearing feeling.

[0038]

The highly moisture-permeable waterproof material of the present invention has, as a surface coating layer, a non-porous layer of polyurethane modified with a hydroxyl group-containing silicone oil having a branch by a siloxane bond. It has high moisture permeability that cannot be obtained with oil-modified polyurethane, and has excellent waterproofness, stain resistance, abrasion resistance, surface activity and surface strength, and the surface feels like the touch of natural leather. It is a highly moisture-permeable waterproof material that has a smooth texture without a slimy feel, a solid appearance similar to natural leather and a deep color. Since a polyurethane having a high solution viscosity was selected as the polyurethane to be combined with the silicone oil and the aromatic polyisocyanate, there is little increase in viscosity and gelation of the composition liquid for coating, and stable coating work can be performed, so that industrial application is possible. It can be manufactured stably.

Claims (3)

[Claims] 1. A 30% by weight DMF on one surface of a fibrous substrate.
Polymer mainly composed of polyurethane elastic polymer obtained by reacting a polyurethane having a viscosity of 150 poise or more in a B-type viscosity system at 25 ° C., a hydroxyl group-containing silicone oil having a branch by a siloxane bond, and an aromatic polyisocyanate Highly moisture-permeable and waterproof material with a coating layer. 2. A 30% by weight DMF on one surface of the fibrous substrate.
A composition comprising a polyurethane having a viscosity of 150 poises or more in a B-type viscosity system at 25 ° C. at 25 ° C., a hydroxyl group-containing silicone oil having a branch by a siloxane bond, an aromatic polyisocyanate, and an organic solvent is applied, and a urethane reaction is carried out. A method for producing a highly moisture-permeable and waterproof material for forming a polymer coating layer. 3. A 30% by weight DMF on the surface of the release sheet.
One side of the fibrous substrate is coated with a composition consisting of a polyurethane having a viscosity of 150 poise or more in a B-type viscosity system at 25 ° C. at 25 ° C., a hydroxyl group-containing silicone oil having a branch by a siloxane bond, an aromatic polyisocyanate, and an organic solvent. A method for producing a highly moisture-permeable and waterproof material, which comprises laminating on and subjecting it to a urethane reaction to form a coating layer of a polyurethane polymer.