JPH0126607B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] This invention relates to a method for producing a moisture-permeable polyurethane polymer as a polymer material suitable for moisture-permeable waterproof fabrics and the like. [Prior Art] Conventionally, a method of obtaining a waterproof fabric that allows gaseous moisture such as humidity to pass through but not liquid moisture such as rainwater, involves stretching a fabric and a highly crystalline tetrafluoride resin. A method of laminating microporous films, a method of weaving ultra-fine threads at a density several tens of times that of normal textiles, and a method of making the gaps between threads smaller than raindrops and larger than water vapor, or amino acid-based polymers. There is a method of coating a base fabric with a hydrophilic polymer that easily absorbs and releases water. On the other hand, as a method of imparting hydrophilicity to polyurethane polymers, it is well known to use polyoxyethylene glycol or a block copolymer of polyoxyethylene and polyoxypropylene as the polyol component. Furthermore, by lightly cross-linking an isocyanate-terminated prepolymer obtained from polyethylene oxyglycol with a molecular weight of 4,000 to 25,000 and an organic diisocyanate using an equivalent amount of water or an organic polyamine, a polyurethane hydrogel having a water absorption capacity several times its own weight is produced. It is also known that the following can be obtained (Japanese Patent Application Laid-open No. 13891/1983). [Problems to be solved by the invention] However, when polyoxyethylene glycol is used alone or in combination with polyoxypropylene glycol, or when a copolymer of both is used as a polyol component, the polyoxyethylene glycol content is proportional to the polyoxyethylene content. The swelling property of the polymer tends to increase due to water absorption, and it has the disadvantage of causing a significant decrease in strength when it swells. Therefore, in the past, only materials that could be used as upper skin materials for clothing and coverings could be obtained. Nakatsuta. Therefore, the object of the present invention is to obtain a moisture-permeable waterproof fabric that has excellent moisture permeability, exhibits no or very little swelling (volume change) due to water absorption, and is therefore suitable as a material for raincoats and uppers of footwear. The present invention provides a method for producing a moisture permeable polyurethane polymer. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention aims to reduce the polyoxyethylene content of a polyester obtained from a relatively low molecular weight polyethylene glycol having a molecular weight of 200 to 600 and an organic dicarboxylic acid. is 17 to 70% by weight and has a molecular weight of 500 to 3000 as a polyol component, and by using this, an organic polyisocyanate, and a chain extender, the final polyoxyethylene content is 15 to 62% by weight. By adopting a manufacturing method that produces a polyurethane polymer in the range of
% or less. The low molecular weight polyethylene glycol used in this application for the production of polyester polyols is:
It is limited to those with a molecular weight in the range of 200 to 600. If the molecular weight is less than 200, the moisture permeability is low;
If it exceeds 600, the swelling rate upon water absorption increases and the mechanical strength decreases significantly when wet, making it unsuitable for uses such as raincoats. There are no restrictions on the organic dicarboxylic acid used in the production of polyester polyol as long as it can undergo an esterification reaction with polyethylene glycol, but particularly preferred are adipic acid or isophthalic acid alone, or combinations of these dicarboxylic acids and ε-
It is a combination system of caprolactone and/or short chain polyols such as 1,4-butanediol, ethylene glycol, and propylene golicol. Among the polyester polyols obtained from the above polyethylene glycol and organic dicarboxylic acid, the polyoxyethylene content is 17 to 70% by weight.
The polyol component targeted by this application has a molecular weight of 500 to 3,000. If the polyoxyethylene content of the polyester polyol is less than 17% by weight or the molecular weight is less than 500, the former will have insufficient moisture permeability and the latter will yield only a hard resin, while the polyoxyethylene content of 70% If it is more than 3000% by weight or the molecular weight is more than 3000, the former will have a large swelling ratio and the latter will have poor strength properties, making it impossible to achieve the initial purpose. Examples of organic polyisocyanates used to polyurethanize the specific polyester polyol obtained in this way include diisocyanates such as hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), and hydrogenated MDI. However, in the case of applications where discoloration is acceptable, any known TDI, MDI or crude MDI can also be used. Further, adducts or prepolymers of polyol and isocyanate, or trifunctional or higher functional organic polyisocyanates can be used in combination, if necessary. However, when using materials containing polyol in the isocyanate component, such as prepolymers and adducts, it is necessary to take into account the effect on the final polyoxyethylene content when made into a polyurethane polymer. be. All known chain extenders can be used in conjunction with polyurethanization in this application, such as diols such as ethylene glycol and 1,4-butanediol, and 4,4-methylenebis-(2- chloroaniline), isophoronediamine,
Examples include diamines such as piperazine and ethylenediamine, and amino alcohols such as N-methylethanolamine and monoethanolamine. Even if the polyurethane polymer is produced using the above-specified polyester polyol, organic polyisocyanate, and chain extender, the polyoxyethylene content in the final polyurethane polymer is in the range of 15 to 62% by weight. If the final polyoxyethylene content is less than 15% by weight, the moisture permeability will still be poor, and if the final polyoxyethylene content is less than 15% by weight,
If it exceeds this, the swelling rate will increase, and even if the fabric is coated or laminated, the durability will inevitably decrease due to the decrease in the physical properties of the polymer layer when wet, which will cause problems in practical use. Note that the polyurethane polymer produced according to the present invention can be particularly suitably used for moisture-permeable waterproof fabrics, but is not limited thereto. In particular, it goes without saying that the present invention can also be applied to other applications in which films or sheets are coated. [Example] Examples 1 to 11 1 Production of polyester polyol A combination system of polyethylene glycol and organic dicarboxylic acid, or organic dicarboxylic acid and ε-caprolactone, or organic dicarboxylic acid and low molecular weight glycol in the ratios shown in Table 1, and is a triple combination system composition of organic dicarboxylic acid, ε-caprolactone, and low molecular weight glycol, and tetrabutyl titanate is added at 0.001% relative to the mixed amount of the composition.
% and stirred in the flask at 200-210℃.
The mixture was heated to perform an esterification reaction. While continuing the reaction for 20 hours, dehydration was carried out under reduced pressure, and each
-K 11 types of polyester polyols were obtained. The polyoxyethylene content and molecular weight calculated from these mixing ratios were as shown in Table 1.

[Table] 2 Manufacture of polyurethane polymer Using various polyester polyols A to K shown in Table 1, prepare an isocyanate-terminated prepolymer according to the formulation shown in Table 2,
Add dimethyl formaldehyde to this with a solid content of 30%.
Then, a chain extender was added to obtain a polyurethane polymer. This liquid polyurethane polymer was poured onto a glass plate using a film applicator to a thickness of 45 microns and a width of 30 mm.
A 150mm film was obtained. This film was marked with marked lines at 100 mm intervals and immersed in water at room temperature for 24 hours.
After 24 hours had elapsed, it was taken out of the water, the distance between the gauge lines (l) was measured immediately after that, and the value calculated using the following formula was taken as the water absorption swelling rate. Water absorption swelling rate (%) = (l-100) x 100/100 Next, using the 45 micron thick film obtained above, moisture permeability was measured according to the method of JIS Z 0208. The measurement results for each were as listed in Table 2. When 1,4-butanediol (BG) among the chain extenders shown in Table 2 is used, a given polyester polyol can be reacted with an organic isocyanate in one shot in the presence of the chain extender.

〔Effect of the invention〕

As mentioned above, the molecular weight of the polyethylene glycol that becomes the polyoxyethylene unit is an important requirement for this application, and the polyoxyethylene unit is present dispersed in small block units in the final polyurethane, and its content is 15 By setting it in the range of ~62%, it is possible to maintain a high moisture permeability while reducing the water absorption swelling rate and obtain a polyurethane polymer that can be used as a material for moisture-permeable waterproof fabrics and footwear uppers. be.

Claims (1)

[Claims] 1. Polyethylene glycol with a molecular weight of 200 to 600 is reacted with an organic dicarboxylic acid alone or a mixture of an organic dicarboxylic acid and ε-caprolactone and/or a short chain polyol to form a polyethylene glycol with a polyoxyethylene content of 17 to 70% and a molecular weight of 500. ~3000 polyester polyol and then using this polyester polyol with an organic polyisocyanate and a chain extender to reduce the polyoxyethylene content.
A method for producing a moisture-permeable polyurethane polymer, characterized in that the polyurethane content is 15 to 62%.