JPS6028304B2 - Method for manufacturing sheet-like products - Google Patents

Description

Detailed Description of the Invention The present invention provides a stable porous layer made of polyurethane or a polymer composition mainly composed of polyurethane, which has low excessive rubber-like rebound, high air permeability and moisture permeability, and has a leather-like structure. The present invention relates to a method for manufacturing a porous sheet material suitable for the surface layer of a material.

Many methods have been proposed in the past for producing porous films of polymers suitable for surface layers or surface layers of leather-like materials.

In particular, many methods are known for forming a stable porosity layer by adding a coagulation regulator such as an activator to a solution of a polymer such as polyurethane, and furthermore, adding an emulsion of ionic polyurethane to the polyurethane solution. , addition of emulsions of other polymers, or simply addition of water have also been proposed as methods for forming stable porous layers. It is true that a stable porous layer can be formed by these methods, and the pore structure of the porous layer can also be changed arbitrarily. However, when trying to make soft leather-like materials or materials with high air permeability and moisture permeability that require high drapability, such as leather-like materials that are more flexible and firm, it is difficult to find a well-balanced texture. The performance of the porous film or porous layer suitable for the surface layer is not satisfactory. Therefore, as a result of extensive research in view of the above objectives, the present invention has been achieved. In other words, the object of the present invention is to create a material that is made of polyurethane or a polymer composition mainly composed of polyurethane, has a stable porous structure, is flexible, has little excessive rubber-like rebound, has high air permeability and moisture permeability, and has flexible drapability. The present invention provides a method for producing a sheet material having a porous layer suitable for the surface layer of a leather-like material with excellent properties.

Another purpose is to obtain a sheet-like material that can obtain the pore structure of a porous layer to obtain a leather-like material suitable for various purposes, from soft texture such as clothing to hard texture such as men's shoes. It is in the manufacturing method. The method of the present invention is characterized in that the polyurethane composition of the polyurethane or polyurethane-based polymer composition used to make the porous layer has (1) a substantial nitrogen content of 3.0 to 6.5% by weight based on isocyanate groups; 5 to 2 parts by weight of a polyurethane or a polymer composition based on polyurethane that is soluble in a solvent, t2) 93 to 45 parts by weight of a solvent for the polyurethane or polymer composition, and an amount of nitrogen based on '31 isocyanate groups of 4.5 parts by weight. ~
7.0 wt.
．． 0 to 13 parts by weight (within a range that does not gel the solvent-soluble polyurethane or polymer composition), '51 selected from aromatic hydrocarbons, aliphatic hydrocarbons, or alicyclic hydrocarbons having 6 to 10 carbon atoms. At least one type 0.15-8
parts by weight and (1) 0.3 to 2 parts by weight of at least one of surfactants and/or coagulation regulators, and optionally at least one selected from water-soluble aliphatic ketones.
It is a polyurethane composition liquid consisting of 0.1 to 5 parts by weight of various types. Next, the polyurethane composition solution is applied onto a support such as a plastic sheet, metal belt, or non-metallic plate, or a substrate made of woven fabric, rope cloth, entangled nonwoven fabric, paper, or any of these fibrous materials containing a flexible resin. to form a composition liquid layer, and then apply a coagulation liquid of all polymer non-solvent systems (if all are non-solvent, or if the composition liquid is a polymer solvent and a non-solvent) to the coagulation liquid temperature. 55oo~
The polymer composition liquid layer is solidified into a porous layer by immersion in a bath adjusted to 20 qo, preferably 50 oo to 2,500 qo, and washed to remove solvents, etc., and additives such as surfactants are added as necessary. Remove.

The most distinctive feature of making the porous layer of the present invention is
'1} It's in the liquid composition.

That is, a solution of polyurethane or a polymer composition mainly composed of polyurethane, which is substantially impermeable to its solvent,
The non-ionic, small particulate polyurethane having a suitable degree of swelling is dispersed, preferably to form a homogeneous dispersion. Furthermore, when forming pores by wet coagulation, a surfactant is used to help change the pore shape or the density of the porous layer as desired, and to maintain the dispersibility of the small-sized polyurethane. or/
and coagulation regulators and water. In order to make the pore partition walls dense, a composition obtained by adding at least one hydrocarbon selected from aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons having 6 to 10 carbon atoms is used. thing. ■
The above composition is a polymer in a non-solvent, preferably a mixed composition of a polymer solvent and a non-solvent, and the temperature of the coagulation liquid is determined by the pores formed by the action of the surfactant and/or coagulation regulator in the composition. The structure solidifies by being immersed in a coagulation bath at a temperature with substantial changes. Therefore, the above polymer composition is flooded to a temperature such that part or all of the added surfactant and/or coagulation regulator dissolves or becomes molten in the composition, and in that state, the polymer composition It is important to form a coating layer on the product and immerse it in a non-solvent coagulation bath under conditions that can substantially alter the pore structure formed by green coagulation. The porous layer obtained by the method of the present invention has 4. fine voids partially formed around the granular polyurethane core, while the pore partition walls are relatively dense and have a high compressive deformation resistance, and the porous layer The internal peeling strength (strength required to adhere to the substrate on both sides of the porous layer and tear the inside of the porous layer) is high, yet the entire porous layer has a high peel strength against large planes with a diameter of several tens of microns or more. It is a porous layer with high air permeability and green permeability, in which vertical pores appear to be arranged.

When this porous layer is used as the surface layer of a leather-like sheet, it has low repulsion, is difficult to be pressed into shape, has high surface strength, has good folding wrinkles, and has high air permeability and moisture permeability. You can obtain superior products that cannot be obtained with conventional methods.
The polyurethane used in the method of the present invention may include any polyurethane that is generally used when making leather-like sheets.
Although the type is not particularly limited, it must not form porosity in a wet coagulation method, be highly adhesive, lack thermoplasticity, or have poor bending resistance.

Therefore, the polymer diol constituting the soft segment is a polyester, polyether, or polyester ether with a molecular weight of about 500 to 3000, the organic diisocyanate is preferably a ring-containing diisocyanate, and the chain extender is preferably a glycol with a molecular weight of 400 or less. Hydroxylamines whose reaction rate is not excessively high are used, such as ring-containing diamines, as well as diamines whose reaction rate is slow. In order to form a porous layer by a wet method, it is necessary to have a certain degree of hard segment area, and the proportion of hard segments is 3.0 to 6.5% by weight of nitrogen based on isocyanate groups. The range is suitable. This polyurethane is a polyurethane that is soluble in a solvent. The fact that it is soluble in a solvent does not mean that the solvent is particularly limited, but since it is a relatively high molecular weight polyurethane suitable for making leather-like sheets, at least dimethylformamide (DMF), dimethyl sulfoxide (DMSO) ), tetrahydrofuran (THF
) or organic compounds similar to these are preferably used. In addition, the soft segment polymer diol of the small particulate polyurethane added to the polyurethane solution of the present invention is, for example, polyethylene adipate glycol, polyethylene propylene adipate glycol, polypropylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate glycol, etc. In addition to base glycol, polycaprolactone glycol, etc., polyester type polymers obtained by condensation reaction of at least one type of aliphatic dicarboxylic acid or aromatic dicarboxylic acid with at least one type of aliphatic glycol, IJ col, and lactone ring polymerization. Obtained polylactone glycol.

Polyether type polymer glycols such as polypropylene ether glycol, polytetramethylene ether glycol, polyethylene propylene ether glycol, etc. Furthermore, polyester ether type polymer glycol. or a polymer triol such as propylene oxide and trimethylolpropane in the soft segment;
Polyether type polymer triol or polyether type polymer such as propylene oxide and hexane triol, propylene oxide and glycerin, condensation polymer of propylene oxide-ethylene oxide-glycerin, condensation polymer of polyester glycol and methylolpropane or glycerin At least one type of soft segment selected from triols, etc., and the average molecular weight of this soft segment is 300 to 20.
00, preferably 400-1400. The selection of this soft segment is carried out appropriately depending on the desired particle size and degree of swelling of the small particulate polyurethane, but it also varies depending on the relationship with the molecular structure of the soft segment of the polyurethane in the solution. For example, if the soft segment of the polyurethane in the solution has the same chemical structure, or if both soft segments have mutual affinity, even if the molecular weight of the soft segment of the small polyurethane is large, the porous material that is the object of the present invention Although it does not have a significant effect on the physical properties of the layer, if the chemical structures of the two soft segments are different or if the soft segments have poor affinity, it is recommended to reduce the molecular weight of the soft segment of the small polyurethane. In view of the physical properties of the porous layer, preferably, increasing the molecular weight of the soft segment deteriorates the physical properties of the porous layer. Therefore, in practice, a soft segment with an optimal molecular weight is used based on preliminary tests. Although the organic polyisocyanate is not particularly limited, it is preferably an organic polyisocyanate containing an aromatic ring, such as tolylene diisocyanate, xylene diisocyanate, or triisocyanate, which is a reaction product of trimethylolpropane and tolylene diisocyanate. Polysocyanate. In addition, as a crosslinking agent, when a trifunctional or higher functional one is used in the soft segment and/or organic polyisocyanate, low molecular weight glycol or diamine with a molecular weight of 500 or less such as ethylene glycol, propylene glycol, butylene glycol, etc. Hydroxylamine etc. may also be used, but when a difunctional one is used for the soft segment or/and organic polyisocyanate, trimethylolpropane, glycerin, hexanetriol, bentaerthritol, triethanol A crosslinked polyurethane is produced by using a polyfunctional, low molecular weight compound such as an amine with a molecular weight of 500 or less. And the degree of crosslinking is determined by mixing the polymerized polyurethane with DMF at room temperature.
The degree of base swelling determined by soaking in the base is 3 to 9, preferably 4.
It is experimentally determined to be in a range of ~7. This is because the theoretically determined degree of crosslinking does not reach the desired range due to various factors such as the raw material of the urethane and the polymerization conditions. If the degree of weight swelling of this crosslinked polyurethane is low, that is, if the degree of crosslinking is high, not only the air permeability and moisture permeability will be lowered, but also various performances such as the strength of the obtained porous layer will be lowered. On the other hand, when the degree of crosslinking is low and the degree of swelling is high, air permeability and moisture permeability become high, but various properties such as the strength of the bound porous layer deteriorate, which is not preferable. Therefore, in order for the performance of the porous layer to meet the performance set for the leather-like sheet, it is necessary to
It is necessary that the vehicle volume swelling degree at F is in the range of 3 to 9, preferably 4 to 7. Here, the degree of weight swelling in DMF is determined by producing a dry film with a thickness of 0.5 from the polyurethane by a casting method, and soaking the obtained film in DMF at 30°C for 4 hours. This is the value expressed as the weight ratio between after cleaning and before trench immersion. Furthermore, it is important that the above-mentioned crosslinked polyurethane is nonionic.

If ionicity is imparted to this crosslinked polyurethane, the effect of the surfactant and/or coagulation regulator used to adjust the pore structure as desired when forming a porous layer by wet coagulation can be suppressed, This is because the pore structure cannot be adjusted sufficiently due to interference. Furthermore,
The crosslinked polyurethane must be a small granular polyurethane, and the average particle diameter of the small granules observed under a microscope is 0.
The particle size is 1 to 3 μm, preferably 0.3 to 2 μm, and the particle size does not necessarily have to be a constant size, but may be distributed.

However, the presence of a large number of large particles, such as 50 or more peaks, must be avoided since this will cause variations in the performance of the obtained porous layer. 4. To make granular polyurethane, when making crosslinked polyurethane, it is made by emulsion polymerization in a non-solvent or by mechanical dispersion during the polymerization process. In this case, when making a porous layer, It is also a preferred method to disperse a part or all of a surfactant and/or a coagulation regulator used to control the pore structure to form small granular polyurethane. Any desired small granular polyurethane in the present invention can be used as long as it satisfies the above limitations, but
In particular, a method in which a low-molecular-weight triol with a molecular weight of 1000 or less, preferably 500 or less, used in the synthesis of a prepolymer is dispersed into fine particles with a liquid mainly composed of water containing an emulsifier, and at the same time or after the dispersion, a chain extension reaction is carried out. The product produced by the above method has good dispersion stability and is therefore suitable for industrial use.

In addition, more preferable additives for both pore structure control and granular polyurethane production are nonionic surfactants and ionic surfactants, and particularly preferable ionic surfactants include anionic surfactants with a weight of 20% :80 to 90:10, especially 45:55 to 70:30. In addition, water may be used as the non-solvent to make the cross-linked polyurethane into small particles, but in this case, aromatic hydrocarbons having 6 to 10 carbon atoms are used to make the pore partition walls denser, as described above. , aliphatic hydrocarbons, or alicyclic hydrocarbons, and if necessary, ketones such as acetone or methyl ethyl ketone may also be used in combination to bring about good results. In addition, the surfactants and coagulation regulators used to regulate the above-mentioned pore formation include, for example, the highest chain alcohols such as stearyl alcohol and cetyl alcohol, sorbitol such as sorbitan stearate and sorbitan/gulmitate, and long chain carboxylic acids. Various compounds described in Japanese Patent Publication No. 45-39634, Japanese Patent Publication No. 45-39635, and Japanese Patent Publication No. 47-19622 filed by the applicant, such as reactants and derivatives thereof, HLB
Higher fatty acid ester or ether of polyoxyethylene glycol or polyoxyethylene-polyoxypropylene glycol, polyoxyethylene glycol or polyoxyethylene-polyoxypropylene glycol with a relatively large value of 8 to 20, preferably 13 to 20. Nonionic surfactants such as alkyl phenyl or alkyl naphthyl ether, polyoxypropylene-polyoxyethylene glycol, and anionic surfactants of sulfate ester type, sulfonic acid type, and phosphate ester type are preferable. In addition, as aromatic hydrocarbons having 6 to 10 carbon atoms,
Benzene, toluene, xylene, ethylbenzene, ethyltoluene, isopropylbenzene, trimethylbenzene, tetramethylbenzene, methylisopropylbenzene, diethylbenzene, butylbenzene, etc.
Aliphatic hydrocarbons include hexane, methylbentane,
Dimethylbutane, heptane, dimethylbentane, methylhexane, octane, methylheptane, trimethylbentane, nonane, trimethylhexane, decane, etc., and alicyclic hydrocarbons include cyclohexane, methylcyclobentane, dimethylcyclobentane, methylcyclohexane, Ethylcyclobentane, dimethylcyclohexane, ethylcyclohexane, propylcyclohexane, butylcyclohexane.

At least one type of hydrocarbon selected from hexane and the like. This hydrocarbon helps to make the pore partition walls denser, but if they are used in large amounts, they become too dense, giving rise to a rubber-like repulsive feeling, decreasing flexibility, and reducing air permeability. Moisture permeability also decreases, therefore the amount used is 0.1
5 to 8 parts by weight is preferred. In the method of the present invention, by using many different types of additives in combination as described above, it is possible to obtain a surface with no or thin surface skin, which is not easily obtained by conventional methods, and yet with sufficient strength and large size. Despite being a porous layer with a pore structure as its main component, we were able to create an excellent layer with sufficient performance to be used as the surface layer of a leather-like sheet. This results in an amazing synergistic effect.

The polymer composition forming the porous layer of the present invention is
The composition ratio of the above-mentioned solvent-soluble polyurethane and substantially solvent-insoluble small granular polyurethane is 95:5 and 60:4.
0 preferably in the range of 85:15 to 70:30.

If the amount of small granular polyurethane is small, the resilience of the porous layer will increase and the air/moisture permeability will decrease, while if the amount of small granular polyurethane is large, the porous layer will become stiff and the peel strength will decrease. As a result, it becomes impermeable as a surface layer of a leather-like sheet. However, if used for other purposes, it is also possible to use it beyond the above range. The porous layer obtained by wet coagulation by the method of the present invention has an average thickness of 0.3 ribs and an air permeability of 1 as measured by JIS-P-8117.
Less than 50 seconds/100', preferably 10 seconds/100
[2] or less, and has a moisture permeability of at least 1,500 ta' as measured in accordance with JIS-K-6549, preferably 2
You can obtain high air permeability and moisture permeability of 000 yen/〆/dokuy. Furthermore, this porous layer combines with the base material and maintains high air permeability and moisture permeability even when the surface is finished with a tan finish or is embossed to give it a leather-like appearance. 4. Creases and wrinkles similar to that of leather can be generated, and the sheet can have excellent performance as a leather-like sheet. Next, the method of the present invention will be specifically explained using examples, but the method is not limited to these examples.

In the examples, parts and percentages are by weight unless otherwise specified. Examples 1-4 DMF-soluble polytetramethylene ether with a nitrogen content of 5.0% based on isocyanate groups obtained from polytetramethylene ether glycol with an average molecular weight of 1100, diphenylmethane diisocyanate and ethylene glycol Polyurethane (hereinafter referred to as PTG-PU) 1 Moribe, a nonionic crosslinked polyurethane obtained from polypropylene ether glycol with an average molecular weight of 700, tolylene diisocyanate, and trimethylolpropane, with a nitrogen content based on isocyanate groups of 5.3 3 parts of small granules of polypropylene ether polyurethane (hereinafter referred to as PPG-PU) with a weight swelling degree of 4.7% in DMF and an average particle size of about 0.6 mm, (hereinafter referred to as PPG-PU), Composition ratio is 80:20), DMF 79.5 parts, water 2.5 parts,
1.8 parts of toluene, 0.0 parts of acetone. Gunbe, HLB18/
0.06 part of anionic surfactant, 0.06 part of anionic surfactant with HLB35, 0.7 part of stearyl alcohol
A polymer composition liquid consisting of 5 parts was made into a uniformly dispersed state, and the mixture was heated to a temperature of about 5,500 ℃, and then diluted and coated on a polyethylene sheet in an amount of about 400 ml of composition liquid.
Next, the porous layer was immersed in a 30% DMF aqueous solution at a temperature of 30q0 to solidify completely, washed with water to remove the solvent and unnecessary additives, and the resulting porous layer was peeled off from the polyethylene sheet and dried in a pin tenter dryer. The width was fixed and dried.

The physical properties of the porous polyurethane film obtained in relation to the particle size of the crosslinked PPG-PU are as shown in the following table. In other words, as the size of cross-linked PPG-PU particles increases, the peel strength within the film decreases, the texture becomes resilient and stiff, moisture permeability decreases, and the surface of the leather-like sheet decreases. It becomes undesirable for layer use. Examples 5 to 8 Nitrogen amount 4 based on isocyanate groups obtained from polycaprolactone glycol with an average molecular weight of 2000, diphenylmethane diisocyanate, and ethylene glycol
．． 6% DM ``Soluble polycaprolactone polyurethane (PCL-PU) and average molecular weight 50090012
Using five types of polypropylene ether glycol 0018002900, tolylene diisocyanate and trimethylolpropane are reacted to form a nonionic crosslinked polyurethane with a nitrogen content of 5.7% based on isocyanate groups and an average particle size of 0.8 French. Small granular PPG-P
U was prepared, and a solution having the same composition as in Example 1 was cast on a polyethylene sheet in an amount of approximately 500 coats per elbow, coagulated in a 30% DMF aqueous solution, washed with water, and dried. The physical properties of porous polyurethane film were determined by PPG-
A comparison in relation to the molecular weight of the soft segment of PU is shown in the following table.

In addition, the porous polyurethane film obtained here was laminated onto the surface of a flexible substrate with a thickness of 1.2 ribs made of ultrafine fiber Toori nonwoven fabric containing polyester polyurethane, and the surface was further colored and heated embossed. A leather-like sheet was prepared using the method, and the physical properties of each sample were measured, and the results are shown in the table below.

In other words, this example deals with the case of PCL-PU and PPG-PU using soft segments with poor compatibility, but even in this case, excellent performance can be achieved by reducing the molecular weight of the soft segment of PPG-PU. A porous polyurethane film could be obtained.

Examples 9 to 13 OMF-soluble polycaprolactone polyurethane (referred to as PCL-PU) obtained from polycaprolactone glycol with an average molecular weight of 2000, diphenylmethane diisocyanate, and butylene glycol, and an average molecular weight of 75
A nonionic crosslinked polyurethane (PPG) obtained by reacting ethylenediamine with a prepolymer obtained from polyether triol, which is a condensation product of propylene oxide and trimethylolpropane, and tolylene diisocyanate.
A polymer composition obtained by changing the composition ratio of PCL-PU and PPG-PU is a polymer composition obtained by changing the composition ratio of PCL-PU and PPG-PU. The sum of 13 parts, DMF 81.5 parts, n-heptane 2. Togegun, 2.5 parts of water, 0.07 part of HLB 16 nonionic surfactant, 0.05 part of HLB 35 phosphate ester type anionic surfactant, 0.15 part of methyl stearate, 0.70 part of stearyl alcohol. Adjust the polymer composition liquid to a uniformly dispersed state and heat it to a temperature of about 50℃.
It was flooded with CO.

Next, the above polymer composition liquid was cast onto a polyethylene sheet in an amount equivalent to approximately 0.0 m/min, and DMF40
The physical properties of porous polyurethane films obtained by coagulating in a % aqueous solution, washing with methanol, washing with water, and drying with a fixed width using a pin tenter are shown in the following table in relation to the polymer composition.

In other words, if the method of the present invention is followed, the pores of the porous film will be stable and the surface will be smooth because of the good desolvation property after solidification, but as shown in Comparative Example 4, if the method is With the agent alone, a skin layer was formed, and the porous film obtained thereby had a strong rebound feeling, and in addition, the removal of the solvent was slow, so the surface was slightly uneven during drying.

Furthermore, if the method of the present invention is followed, the porous film obtained will have a low initial Young's modulus, flexibility, and high moisture permeability, and when finished by adhering to a leather-like sheet substrate, the surface physical properties will be improved. An excellent leather-like sheet with good folding wrinkles was obtained. On the other hand, the polymer composition is d as shown in Comparative Example 5.
- When the amount of granular polyurethane added increases, the resulting porous film becomes stiff and brittle, making it unsuitable for the surface layer of a leather-like sheet.

Next, the above composition liquid was applied to the surface of a flexible substrate made by adding polyester polyurethane to a sub-fabric made of entangled polyethylene terephthalate ultrafine fibers, and having a thickness of about 1.0 mm, for about 500 minutes/day. A sheet material obtained by casting that amount, wet coagulating, washing, and drying in the same manner as above has a porous surface layer in the same state as above.
The products of the present invention had high moisture permeability and firm flexibility, but the products of the comparative example had a feeling of resilience, were stiff, and did not have good folding and wrinkling. Example 14 ~ DM with a nitrogen content of 3.7 based on isocyanate groups obtained from Shigeru polybutylene adibate glycol, diphenylmethane diisocyanate, and hexamethylene glycol
F-soluble polybutylene adibate-based polyester polyurethane (referred to as PBA-PU) and an average molecular weight of 1270
A nonionic crosslinked polyurethane (referred to as PPA-PU) obtained by reacting polypropylene adibate glycol, tolylene diisocyanate, and pentylthritol.
4. Granular PPA-PU with an average particle size of 1.1 μm and a nitrogen content of 6.2% based on isocyanate groups was prepared, and it was
A polyurethane composition was prepared by mixing 85 parts of BA-PU and 15 parts of PPA-PU, and adding 15 parts of total polyurethane and the additive composition as shown in the following table. The following table compares the physical properties of the porous film obtained by casting the film in an amount of 500 μm per coat, wet coagulating in a non-solvent, washing off the soot, washing with water, and drying in relation to the additives. become.

Claims (1)

[Claims] 1 (1) Nitrogen amount based on isocyanate groups 3.0 to
6.5% by weight of a substantially solvent-soluble polyurethane or a polyurethane-based polymer composition, (2) 93-45 parts by weight of a solvent for the polyurethane or polymer composition; (3) 0.3 to 13 parts by weight of a nonionic, substantially solvent-insoluble, small particulate polyurethane with a nitrogen content of 4.5 to 7.0% by weight based on isocyanate groups; (4) 1.0 to 13 parts by weight of water; (However, within the range in which the solvent-soluble polyurethane or polymer composition does not gel) (5) At least one kind of 0. 15 to 8 parts by weight, and (6) 0.3 to 2 parts by weight of at least one of surfactants and/or coagulation regulators is applied onto a support or a substrate containing a fibrous material. A polyurethane or polymer composition liquid layer is formed, then all polymers are immersed in a non-solvent based coagulation solution to coagulate into a porous layer, washed, dried and optionally additives removed. Therefore, a method for producing a sheet-like article is characterized in that it forms a stable porous layer and has high air permeability and moisture permeability. 2. The production according to claim 1, wherein the substantially solvent-insoluble small-sized polyurethane has an average particle size of 0.1 to 3μ, preferably 0.3 to 2μ, and has a distribution in particle size. Law. 3. The composition ratio of the substantially solvent soluble polyurethane or polymer composition to the substantially solvent insoluble small particulate polyurethane is from 95:5 to 60:40, preferably 85:15.
The manufacturing method according to claim 1, wherein the ratio is between 70 and 30. 4. The manufacturing method according to claim 1, wherein the surfactant is composed of a nonionic surfactant and an ionic surfactant, and the composition ratio thereof is in the range of 45:55 to 70:30. 5. The surfactant and/or coagulation regulator are additives that have the effect of substantially changing the pore structure formed by wet coagulation and are inert to the precipitated polyurethane or polymer. The manufacturing method described in item 1.
6. The manufacturing method according to claim 1, wherein 0.1 to 5 parts by weight of at least one selected from water-soluble aliphatic ketones is added to the polyurethane composition. 7 The small particulate polyurethane has a cross-linked bond and has a weight swelling degree of 3 to 9, preferably 4 to 9 when immersed in dimethylformamide.
7. The manufacturing method according to claim 1, wherein the small granular polyurethane of No. 7 is used. 8 The stiffness of the porous layer obtained by solidification is JIS-P-81.
17, and the moisture permeability is at least 150 seconds/100ml as measured by JIS-K-6549.
The manufacturing method according to claim 1, wherein the production rate is 500 g/m^2/day. 9. The manufacturing method according to claim 1, wherein the porous layer obtained by solidification is combined with the substrate to form a surface layer of a leather-like sheet.