JP3266683B2 - High moisture permeable waterproof material and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a leather having a smooth texture without the slimy feel of natural leather and a solid appearance and color depth similar to that of natural leather. The present invention relates to a highly moisture-permeable waterproof material such as a moisture-permeable waterproof sheet excellent in moisture permeability and waterproofness and excellent in surface strength, and a leather-like sheet material having moisture-permeable waterproof property.

[0002]

2. Description of the Related Art Conventionally, as a moisture-permeable waterproof sheet or a leather-like sheet having excellent moisture permeability, a material that does not allow liquid water such as rainwater to pass through even when water vapor is passed has been demanded. Moisture permeable waterproof sheets and leather-like sheets using a stretched microporous film or a microporous film obtained by wet coagulation of a polyurethane resin as a surface coating layer have been proposed. For example, Japanese Patent Application Laid-Open No. 61-1744
No. 80 proposes a highly moisture-permeable and highly waterproof material using a microporous film obtained by wet-solidifying a polyurethane resin as a surface coating layer. However, the microporous polyurethane film used here is not itself water-repellent, so it needs to be treated with a water-repellent agent, and thus has a problem in durability. In addition, it has stain resistance, abrasion resistance, and surface lubricity. It is inferior to others.

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 JP-A-62-271740 and JP-A-Hei.
No. 192882. All of these leather-like sheets have good moisture permeability and are impermeable to liquid water such as rainwater.However, the surface layer swells when wet with water because hydrophilic polyurethane is used for the skin layer. The appearance was easily violated, and all were poor in stain resistance, abrasion resistance, and surface lubricity. Japanese Patent Application Laid-Open No. 1-113230 proposes a fabric using a nonporous layer of amino acid-modified polyurethane for the skin layer in order to improve moisture permeability. However, the skin layer of amino acid-modified polyurethane has low surface strength and is resistant to In order to improve abrasion, it must be coated with a silicone-modified polyurethane, and sufficient moisture permeability cannot be obtained.

Further, many leather-like sheets using a polyurethane resin having a siloxane bond for the surface coating layer have been proposed, for example, Japanese Patent Application Laid-Open Nos. 62-206086 and 1-1113230. . These leather-like sheets were excellent in stain resistance, water resistance, abrasion resistance and surface lubrication due to the siloxane bond introduced into the polyurethane resin, but were unsatisfactory in moisture permeability.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a surface having excellent moisture permeability, waterproofness, stain resistance, abrasion resistance, surface lubricity and excellent surface strength, which has solved the above-mentioned disadvantages of the prior art. The touch of the hand has a smooth texture without the slimy feeling of natural leather, and it has a durable waterproof sheet and a breathable waterproof sheet with a solid appearance and color depth similar to natural leather An object of the present invention is to provide a highly moisture-permeable and waterproof material such as a leather-like sheet.

[0006]

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

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

In other words, the highly moisture permeable waterproof material of the present invention uses a polyurethane modified with a hydroxyl group-containing silicone oil having a siloxane bond as a coating layer. The effect of the present invention cannot be obtained when a conventionally used silicone oil having no alkyl group in the linear or side chain having no branch due to a siloxane bond is used. The hydroxyl group-containing silicone oil having a branch due to a siloxane bond of the present invention is preferably one having many branches due to a siloxane bond. When the number of branches due to the siloxane bond increases, the solid tends to become an amorphous solid. Therefore, it is important to introduce a substituent having a large steric hindrance such as a phenyl group into a part of the branch to make the 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 the hydroxyl group in the silicone oil is preferably 200 to 800 in terms of the hydroxyl equivalent. If the hydroxyl group equivalent is less than 200, the number of bonding points with the organic polyisocyanate is reduced, so that sufficient film strength cannot be obtained and the moisture permeability also decreases. When the hydroxyl equivalent is larger than 800, there is no problem in terms of moisture permeability, but the reactivity with the organic polyisocyanate increases, and the urethane-forming reaction proceeds rapidly, so that the viscosity of the coating solution increases in a short time. It is poor in processability because of gelation and gelation. Examples of such a hydroxyl group-containing silicone oil having a large number of branches by a siloxane bond include a glycol modified oil: BX16-895 manufactured by Toray Dow Corning Silicone Co., Ltd.

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

In the present invention, the aromatic polyisocyanate reacted with the polyurethane and the hydroxyl group-containing silicone oil has a high urethane conversion reaction rate. Easily causes 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 increase in the viscosity of the composition liquid as it is and cannot be implemented on an industrial scale. Therefore,
The polyurethane used in the present invention is a polyurethane having low reactivity and high solution viscosity, which is not generally used as a conventional prepolymer polyurethane, specifically, a B-type viscosity of a 30% dimethylformamide solution at 25 ° C. It is necessary to use a polyurethane having a total viscosity of 150 poise or more.

The 100% modulus of the polyurethane is:
Those having ^{20 to} 150 kg / cm ² are preferred. If the 100% modulus is large, the texture of the obtained highly moisture-permeable and waterproof material becomes hard, and the grainy feeling, especially when made into a leather-like sheet, is rough and lacks a sense of quality. On the other hand, when the 100% modulus is small, the film strength when the coating layer is formed is weak,
The surface strength of the obtained highly moisture-permeable and waterproof material is reduced.

The terminal group of the polyurethane may be a hydroxyl group terminal obtained by reacting in a hydroxyl group excess system or a terminal group blocked by a terminal blocking agent. In the case of the end-blocked polyurethane, it is considered that the urethanization reaction with the silicone oil and the organic polyisocyanate reacts with a part of the urethane bond through an allohanate bond. Further, the terminal group of the polyurethane may be an isocyanate terminal obtained by reacting in an isocyanate excess system. In the case of an isocyanate terminal, those having an aromatic isocyanate terminal have a high reaction rate and easily cause viscosity increase or gelation in a short time when used as a coating composition solution. Preferably, it is an alicyclic isocyanate.

The weight ratio of the hydroxyl group-containing silicone oil to the polyurethane to be mixed is in the range of 1: 5 to 6: 5, preferably in the range of 2: 5 to 4: 5. When the amount of the silicone oil is increased, the moisture permeability and the water resistance are improved, but the surface strength of the coating layer is reduced and the touch is unfavorably sticky. On the other hand, when the addition amount of the silicone oil is small, the sticky feeling is lost, but sufficient moisture permeability cannot be obtained.

The aromatic polyisocyanate to be reacted with the polyurethane and the hydroxyl-containing silicone oil having a branch by a siloxane bond may be a simple diisocyanate or triisocyanate. It is important to use an adaact polyisocyanate in which a part of the polyol is partially subjected to an addition reaction. The amount of the polyisocyanate to be used with respect to the total amount of the polyurethane and the silicone oil varies depending on the content of the hydroxyl group and the isocyanate group, respectively, but is an equivalent amount, and the weight ratio is 6:
1-11: 1 is a standard.

The polyurethane, the hydroxyl-containing silicone oil having a branch by a siloxane bond, and the organic adduct polyisocyanate are dissolved in an organic solvent to form a coating layer of the highly moisture-permeable and waterproof material of the present invention. And a liquid composition of The organic solvent used for preparing the coating solution for coating in the present invention is 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, chloroform, toluene, perchloroethylene and the like.

Depending on the purpose, the coating composition may contain a coloring agent such as a dye or a pigment, a stabilizer, an antistatic agent, a leveling agent, or a filler such as an inorganic material used in general synthetic leather or artificial leather. Various additives such as agents, concealing agents, softeners, flame retardants, antioxidants, ultraviolet absorbers, dyes, surfactants, coagulation regulators, lubricants and the like can be added.

As the fibrous substrate used in the present invention, conventionally known polyamides and polyesters may be used depending on the use of a highly moisture-permeable waterproof material, that is, the use of a moisture-permeable waterproof sheet for clothing or a waterproof leather-like sheet. Knitted, woven or nonwoven fabrics derived from synthetic fibers such as vinylon, polyacrylonitrile, man-made fibers such as rayon, cupra, acetate, etc., or natural fibers such as silk, cotton, wool, hemp, etc. Any of a base cloth containing an elastic polymer can be used.

Above all, three-dimensionally entangled average single fineness 0.1
A nonwoven fabric made of an ultrafine fiber bundle of denier or less is suitably 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 /. 3, and a fiber wet sheet having 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 composed of polyurethane is laminated on the surface on which the coating layer is formed.

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 release sheet such as release paper, and dried appropriately, and then adhered to the fibrous substrate surface. It can be performed by a conventionally known method such as a transfer method. Care must be taken in the 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 film is inferior in waterproofness. Therefore, in the present invention, a spray coating method, a direct coating method using a doctor knife or the like, or a transfer method using release paper or the like is preferable. The coating amount is preferably an amount that results in a film thickness after drying and curing of 20 to 60 μm. When the thickness of the coating layer is less than 20 μm, it is difficult to obtain a sufficient film strength, and when it is more than 60 μm, the moisture permeability tends to decrease.

The coating layer formed on the surface of the fibrous substrate by coating or transfer method is subjected to a urethanization reaction by evaporating and removing the solvent and then performing a heat treatment. The condition of the heat treatment is not particularly limited, but is usually performed until the isocyanate group substantially disappears.
It is about 24-36 hours at 0 ° C. When the urethane-forming reaction is completed, the release sheet is peeled off to obtain a highly moisture-permeable and waterproof material such as a waterproof cloth or a waterproof leather-like sheet. If the release sheet is peeled off before the urethanization reaction sufficiently proceeds, the surface grain pattern tends to be unclear. The embossing treatment in the case of the direct coating method is performed before the urethanization reaction is completed.

[0022]

EXAMPLES The present invention will be described more specifically 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 base material, 20% of a polybutylene adipate-based polyurethane obtained by adding a blue colorant 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 in which polyurethane is contained in a porous state in an entangled non-woven fabric of bundles of ultrafine fibers obtained by impregnating a dimethylformamide (DMF) solution, coagulating in a 40% DMF aqueous solution, and dissolving and removing polyethylene with a solvent. A base fabric for the sheet was prepared.

A coating liquid having the following composition was prepared as a coating liquid 1 for coating, coated at 70 g / m ² on a release paper having a grain pattern, dried at 100 ° C. for 2 minutes, and further coated with 7
After coating at 0 g / m ² and adhering to the fibrous substrate, drying at 100 ° C. for 3 minutes, curing at 60 ° C. for 48 hours, and releasing the release paper, a leather-like sheet was obtained.

Composition of composition liquid 1: Polytetramethylene glycol-based 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 (trimethylolpropane reacted with 3 equivalents of tolylene diisocyanate) Carbon black-based black pigment dispersion (manufactured by Dainichi Seika) 10 parts Methyl ethyl ketone 25 parts Dimethylformamide 25 parts

The obtained leather-like sheet has a moisture permeability of 180.
In 0g / m ² / 24hr, surface strength, surface feel, color depth were both good. In addition, when the men's shoes were produced from the leather-like sheet, the surface of the shoes was hardly damaged, and the shoes were excellent in moisture permeability and comfortable to wear.

Examples 2 to 4 and Comparative Examples 1 to 4 In the same manner as in Example 1, except that the amount of the silicone oil added to the coating composition and the coating amount of the composition were changed to those shown in Table 1. To obtain a leather-like sheet. However, the silicone oil used in Comparative Example 4 was a linear silicone oil having a hydroxyl group terminal. The performance of the obtained leather-like sheet is also shown in Table 1. Comparative Examples 1 and 2 in which no or little silicone oil was added
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 content of polyurethane. The moisture permeability is based on the method of JIS K6549. As the silicone oil of Comparative Example 4, a linear silicone oil was used.

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

Example 5 In Example 1, the following composition was prepared as the coating composition liquid 2 and 70 g of the composition liquid was prepared on release paper having a grain pattern.
/ M ^2, dried at 100 ° C. for 2 minutes, and further coated with the same composition at 70 g / m ² to adhere to the fibrous substrate.
After drying at 0 ° C. for 3 minutes, it was 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 2: Polyamino acid polyurethane (20% solution) 100 parts (viscosity of 30% solution at 25 ° C .: 530 poise) Silicone oil BX16-895 (manufactured by Toray Dow Co.) 11 parts Adduct polyisocyanate Nato 6 parts (trimethylolpropane reacted with 3 equivalents of tolylene diisocyanate) Carbon black black pigment dispersion (manufactured by Dainichi Seika) 7 parts Methyl ethyl ketone 17 parts Dimethylformamide 17 parts

The obtained leather-like sheet has a moisture permeability of 180.
In 0g / m ² / 24hr, surface strength, surface feel, color depth were both good. In addition, when the men's shoes were produced from the leather-like sheet, the surface of the shoes was hardly damaged, and the shoes were excellent in moisture permeability and comfortable to wear.

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

A coating liquid 3 having the following composition was prepared as a coating liquid 3 and applied to the base fabric by a direct coating method at 150 g / m ^2, dried at 100 ° C. for 2 minutes and embossed by embossing. To obtain a leather-like sheet.

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 Nato 7 parts (trimethylolpropane reacted with 3 equivalents of tolylene diisocyanate) Carbon black-based black pigment dispersion (manufactured by Dainichi Seika) 8 parts Methyl ethyl ketone 17 parts Dimethylformamide 17 parts

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

Example 7 Composition liquid 3 of Example 6 was applied to release paper at 70 g / m ² ,
After drying at 00 ° C for 2 minutes, 50 g / m ^{2 of the} same composition was further applied.
Coated and adhered to the surface of a polyester two-way tricot, dried at 100 ° C for 3 minutes, and then dried at 60 ° C for 48 minutes.
After curing for a 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]

As described above, the highly moisture permeable waterproof material of the present invention has a nonporous layer of polyurethane modified with a hydroxyl group-containing silicone oil having a siloxane bond as a surface coating layer. 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 furthermore, the touch of the surface is similar to that of natural leather. It has a smooth texture without sliminess, and is a highly moisture-permeable and waterproof material with a solid appearance and color depth similar to natural leather. Since the silicone oil and the polyurethane combined with the aromatic adduct polyisocyanate were selected to have a high solution viscosity as the polyurethane to be combined with the aromatic adduct polyisocyanate, the viscosity increase and gelation of the composition solution for application were small, and the application operation could be stably performed. It can be manufactured stably.

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Claims (3)

(57) [Claims] 1. One side of a fibrous substrate is provided with 30% by weight of DMF.
Polyurethane having a viscosity of 150 poise or more in a B-type viscosity system at 25 ° C. of a solution, a hydroxyl-containing silicone oil having a siloxane bond and an aromatic adduct
High moisture-permeable waterproof material with a polymer coating layer consisting mainly of polyurethane elastomer which bets polyisocyanate obtained by reacting. 2. 30% by weight of DMF on one surface of a fibrous substrate.
B type viscosity polyurethane viscosity of more than 150 poises due to system at 25 ° C. a solution, the hydroxyl group-containing silicone oils having a branched by siloxane bonds, a composition comprising an aromatic adduct port <br/> Li diisocyanate and organic solvent is applied , A method for producing a highly moisture-permeable and waterproof material in which a urethanization reaction is performed to form a polymer coating layer. 3. A 30% by weight DMF is coated on the surface of the release sheet.
B type viscosity polyurethane viscosity of more than 150 poises due to system at 25 ° C. a solution, the hydroxyl group-containing silicone oils having a branched by siloxane bonds, a composition comprising an aromatic adduct port <br/> Li diisocyanate and organic solvent is applied And a method for producing a highly moisture-permeable and waterproof material in which a polyurethane polymer coating layer is formed by laminating on one surface of a fibrous substrate and causing a urethane reaction.