JPS5910378B2 - Manufacturing method of porous sheet material with excellent performance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the production of polyurethane elastomers to produce sheet materials with excellent sponging properties and performance.

Conventionally, polyurethane elastomers polymerized using polycaprolactone as a soft segment generally have a narrow range of conditions for forming sponges by wet coagulation, and there are many restrictions on obtaining sheet materials with a good sponge structure.

For example, if the percentage (hereinafter referred to as N%) of nitrogen based on isocyanate groups in the polyurethane elastomer is less than 4.0%, it is difficult to produce a sheet material with a stable sponge structure, while if the N% is high, sponge formation will occur. Although the properties are improved, the sheet material becomes harder, resulting in unfavorable performance depending on the intended use of the sheet material. Furthermore, a polyurethane elastomer obtained by using polycarbonate glycol as a soft segment behaves similarly to polylactone glycol.

The present invention is a polyurethane elastomer obtained by polymerizing the aforementioned polymer glycol with poor wet coagulation properties as a soft segment. This article relates to the manufacturing method of polyurethane elastomer and its wet coagulation conditions.The objective is to achieve hydrolysis resistance, bending resistance, low temperature dependence, and properties such as sponge formation and sponge shape stability. The object of the present invention is to provide a polyurethane elastomer and its coagulation conditions for obtaining an excellent sheet material, especially a leather-like sheet material. In the method of the present invention, the soft segments constituting the polyurethane elastomer are composed of polylactone glycol or polycarbonate glycol having a molecular weight of 500 to 4000, and two or more types of polymer glycols of the same type but having molecular weights different from each other by 100 or more are used. A polyurethane elastomer containing at least 10% by weight of each type of polymer glycol based on all types of polymer glycols is dissolved in a solvent and applied onto a support or base layer to form a solution layer, Next, the polyurethane elastomer is immersed in a coagulation bath with a weight ratio of solvent to non-solvent of 20:80 to 70:30 and coagulated, thereby forming the desired sponge structure and producing a sheet material with excellent performance. It is characterized by the following.

Polymer glycols used as soft segments constituting the polyurethane elastomer of the present invention include polylactone glycols obtained by ring-opening polymerization of lactones such as butyrolactone, valerolactone, and caprolactone, and aliphatic glycols such as propylene glycols. Glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, p-xylene glycol, 1,4
- A polymer glycol selected from polycarbonate glycols obtained by reacting one or two ring-containing glycols or phenols such as cyclohexane diethyl glycol and bisphenols with a carbonate having an active group, such as diethyl carbonate or phosgene. be.

Examples of organic diisocyanates used as hard segments include naphthylene diisocyanate, diphenylmethane diisocyanate, diphenyl diisocyanate, tolylene diisocyanate, xylylene diisocyanate, cyclohexane dimethyl isocyanate,
It is selected from hexamethylene diisocyanate, decamethylene diisocyanate, etc. depending on the performance of the desired polyurethane elastomer. Examples of chain extenders having two active hydrogen atoms in the Zelevitinoff reaction used for chain extension include glycols such as ethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol;
, p'-diaminodiphenylmethane, m-phenylenediamine, 4-methyl-m-phenylenediamine, hexamethylenediamine, and the like can be used. Preferred among these are chain extenders selected from glycols. The method of producing a polyurethane elastomer having soft segments with different molecular weights in the present invention includes (4) using a mixture of polymer glycols with different molecular weights as soft segments in advance;
(8) A method for producing polyurethane elastomers using polymer glycols with different molecular weights as soft segments, and then mixing these polyurethane elastomers.
A), (8) In either method, the formation of a sponge structure in wet solidification, the durability such as bending fatigue resistance, hydrolysis resistance, and abrasion resistance, are both flexible and have little temperature dependence. It is possible to obtain a polyurethane elastomer that is free from tack and has good solubility and solution stability. Compared to many other polyester glycols, the polymer glycol used in the present invention has a narrow molecular weight distribution, and the polyurethane elastomer that uses this as a soft segment has relatively poor wet coagulation properties, but the polyurethane elastomer of the soft segment blend based on the present invention By doing so, it was possible to improve wet coagulation properties.

In the present invention, each of the two or more types of polymer glycols having different molecular weights to be mixed has a molecular weight of 50
0 to 4000, and the molecular weights of each polymer glycol are separated from each other by 100 or more, and the amount of each polymer glycol used must be at least 10% by weight based on the total polymer glycol. It is.

If the difference in molecular weight is small, mixing multiple types of soft segments with different molecular weights will produce an effect, but this will not only complicate the mixing operation but also reduce the effect, so it is preferable from a practical standpoint. do not have. Furthermore, if the molecular weights are extremely different, partial phase separation may occur when the polyurethane solution is wet-coagulated, resulting in some uneven coagulation.

Considering the above, it is more preferable that the molecular weight difference between the polymer glycols is in the range of 200 to 2,000. The N% of the polyurethane elastomer used in the method of the present invention is preferably from 2.5 to 6.5,
Generally, satisfactory results cannot be obtained outside this range.

Further, when the average molecular weight of the mixed soft segments is large, it is better to increase N%. Examples of solvents for dissolving the polyurethane elastomer include N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, tetrahydrofuran, tetramethylurea, dioxane, and gamma-butyrolactone. A non-solvent for polyurethane elastomer is used as a coagulation bath to coagulate a solution of polyurethane elastomer, but if the non-solvent alone is used, the coagulation is too fast and a non-uniform reaction occurs, resulting in the formation of a skin on the surface and wrinkles. Easy to do. To prevent this, a mixture of a non-solvent and a solvent can be used to achieve slower coagulation, but if the solvent content is too large, coagulation will be delayed and eventually no coagulation will be possible. Therefore, the appropriate composition of the coagulation bath is such that the weight ratio of solvent to non-solvent is in the range of 20:80 to 70:30. Polyurethane elastomer solutions contain various additives such as colorants, activators, stabilizers, or polymers of polyacrylonitrile, polyvinyl acetate, polyvinyl chloride, polymethacrylates, polyacrylates, and vinyl halides. Polymers such as can be mixed.

The invention will be further explained below with reference to examples.

In addition, the parts in the examples and ? All references refer to weight unless otherwise noted. Example 1 Polycaprolactone glycol (hereinafter referred to as P) with a molecular weight of 500
It is abbreviated as CL.

) 10701 molecular weight 1000 (7) PCL 60%, molecular weight 1500 (7) PCL 30% mixed polymer glycol 595 parts, P,p'-diphenylmethane diisocyanate 357 parts, ethylene glycol 48 parts to make a polyurethane elastomer with N7O5.2. Synthesized.
This polyurethane elastomer 25701N,N-dimethylformamide (hereinafter abbreviated as "Son") 72%, sorbitan monostearate as a softening agent 1.5%,
A solution consisting of 1.5 parts of stearyl alcohol was prepared.
This solution was impregnated into a nonwoven fabric made of 2 denier nylon-6 staple fibers, and on one side of the nonwoven fabric was impregnated with a solution consisting of 22% polyurethane elastomer, 76.5% DMF, 0.5% stearyl alcohol, and 1% carbon black. It was cast to a thickness of .8 mm and solidified by immersing it in a coagulating solution at 50°C consisting of 50% DMF and 50% water.

The sheet material after removing DMF by washing with water and drying had a good sponge structure. Next, the surface of this sheet material was subjected to finishing treatments such as coloring and embossing to obtain a leather-like sheet material. This sheet material has a flexible texture, flex fatigue resistance, abrasion resistance, hot water resistance,
It had good alkali resistance.

Example 2 Polycarbonate glycol (hereinafter abbreviated as PCG) consisting of bisphenol A with a molecular weight of 800 and phosgene.

) 33%, molecular weight 15000 PCG34%, molecular weight 24
000) A polyurethane elastomer having an N% of 4.5 was synthesized using 535 parts of a mixed polymer glycol consisting of PCG337O, 357 parts of P,p'-diphenylmethane diisocyanate, and 91 parts of 1,4-butanediol. A polyurethane solution consisting of 18% of this polyurethane elastomer, 1% of stearyl alcohol, 1% of water, and 80% of DMF was prepared.

Spread this solution on a glass plate for 1W! Cast to a thickness of I, DM
It was immersed in a 50°C coagulation bath consisting of 50% F and 50% water to coagulate into a sponge structure, rinse the DMF with water, and dry with hot air at 90°C.

The obtained film has a smooth surface and a flexible texture due to its spongy structure, and is extremely durable.When applied to a flexible substrate and given a colored finish, it can be used for carapaces, etc. It was suitable for

Claims (1)

[Claims] 1. The soft segment constituting the polyurethane elastomer consists of polylactone glycol or polycarbonate glycol with a molecular weight of 500 to 4000, and two or more polymer glycols having the same type of structural unit and having molecular weights different from each other by 100 or more. , a layer of a solution of a polyurethane elastomer containing at least 10% by weight of each type of polymer glycol dissolved in a solvent is formed for all types of polymer glycol, and the weight ratio of the solvent and non-solvent of the polyurethane elastomer is 20. A method for producing a porous sheet material with excellent performance, characterized by coagulating it by immersing it in a coagulation bath having a composition of: :80 to 70:30.