TWI384002B - Method for fabricating aqueous polyurethanes - Google Patents

Description

Method for forming aqueous polyurethane

This invention relates to aqueous polyurethanes, and more particularly to methods for their formation.

Polyurethane (PU) has good properties such as comfortable hand, abrasion resistance, rebound elasticity, buckling, chemical resistance, etc., so it is often used in textile coating processing, leather processing, adhesives, Sealant, plastic molding and other purposes. The product type of the industry is mainly solvent-based PU resin. Due to the large amount of organic solvent dilution during the operation, the solvent will be released during heat hardening, which causes the burning and explosion of the processing process. In view of this, coupled with the rise of environmental awareness in the world, the global focus on the use of solvents and subsequent processing issues, for example, the European Union announced that in 2007 ~ 2010 will reduce the VOCs (volatile organic compounds) content of architectural decorative paints and varnishes Half, up to 75g / L, will be implemented in various coating applications in the future. After the development of VOCs related regulations in China, the production capacity of synthetic leather in China has fallen rapidly. In 2005, the output was only 70 million yards. After the production fell to mainland China and South Korea, it ranked third in the world. The synthetic leather guild members have 27 from the peak. There are more than 10 remaining. This year, we will strictly control the use and emission of VOCs. For example, if the resin usage of a production line is 4,000 tons/year, even if the plant is equipped with a gas collection efficiency of 80%, the equipment The 90% efficiency control equipment will pay 7 million air pollution fees every year from 1996 to 1998. After 99 years, it will cost 14.2 million yuan per year. The product type of PU resin is in need of change.

In the field of application of PU resin, the processing which imparts high functionality and feel to the fabric has been highly valued in recent years, and the most widely used for moisture-permeable waterproof processing. At present, the moisture-permeable waterproof PU film can be divided into blown film and coating processing. The advantages of blown film are solventless process, thick film with real feeling, plastic leather texture and good backlash, but the investment in machinery and equipment is high. Slow, high technical threshold and little change in product style make domestic blown film technology and PU film grades uneven; while traditional coating processing has the advantages of fast production speed, cheap equipment and many variations in style, in processing and application technology. It is relatively simple and is the most commonly used process in the industry. However, due to the high content of raw materials and wastewater solvent, high VOCs emissions from process, high gas recovery and exhaust gas washing efficiency, the competition is fierce but the cost is high. In order to reduce the trend of VOCs globally, the development of new raw materials not only needs to reduce the content of VOCs in raw materials, but also considers that users are passive and want to use the original equipment process for production. Therefore, it is only environmentally friendly and safe to water-based PU resin. Sexual regulation is within the scope of the standard, and it has the advantages of engineering mergers. It is also the practice of resin developers and processing industry to avoid falling into the "environmental money pit" cycle.

For the research and development of water-permeable and waterproof PU resin, the hydrophilic non-porous coating is taken as an example. The moisture permeability is adjusted by the hydrophilic group in the PU or the hydrophilic component in the main chain of the molecule. The main component commonly used in the industry is poly. Polyethylene oxide (PEO). The water-based PU with a high proportion of PEO in the main chain of the molecule is not easily synthesized in the synthesis, because the high hydrophilicity of PEO causes the water-based PU to have high swelling property in water, which affects product stability and causes the film forming strength to decrease. Poor and durable. In order to improve the high swellability caused by PEO in water, it has been studied to combine ionic functional groups or PEO as a chain extender for hydrophilic swellability adjustment; in addition, sulfonic acid groups are substituted for carboxylic acid groups to greatly improve aqueous PU. Hydrophilic, reducing the amount of solvent used, which is commonly used in personal products such as cosmetics and shampoo. In the composite formulation, there are also methods in which a water-soluble PEO-aqueous PU and a general aqueous PU are mutually blended, or a PEO main chain is interlaced with a highly hydrophobic segment, and a side chain is appropriately introduced into a hydrophilic swelling property.

JP 2004300178-A discloses a technique for utilizing PEO as an aqueous PU main chain structure in combination with introduction of an anionic functional group for hydrophilic swellability adjustment, since the charged mutual repulsion of anionic functional groups can promote the aggregation of aqueous PU, which limits the PEO molecules in water. The stretch range is such that the hydrophilic swellability of the aqueous PU is also controlled to decrease.

JP 2005060690-A uses a PEO having an amine group at the end as a chain extender, and is added in a final step of aqueous PU synthesis to carry out a chain extension reaction, thereby avoiding the problem of swelling of PEO-aqueous PU in water, resulting in PEO-aqueous PU. It is not used alone. It needs to be further formulated and mixed with general water-based PU to become a coating liquid for fabric moisture-permeable waterproof processing.

WO 2004069903-A1 is a patent of water-soluble PU. The introduction of PU molecular main chain into a large number of PEO structures will cause the PU molecules to be completely dissolved in water, so the water swelling and swelling is quite serious, and only more water can be added to solve the high. Viscosity, can not be processed, so the resulting water-soluble PU solid content is low; this water-soluble PU needs to be mixed with general self-emulsifying water-based PU, and combined with micro-structure phase separation coating technology for moisture-permeable waterproof coating application.

In the aqueous PU composition formulation disclosed in US 2003/0195293-A1, a main chain type and a side chain type PEO structure starting material are mixed, and the PEO content of the main chain is restricted, and a large proportion of PEO is moved to the side chain. The purpose is to keep the main chain hydrophobic, prevent the excessive swelling of the aqueous PU in water, and maintain high physical properties; while maintaining the moderate hydrophilicity with the PEO structure of the side chain, the moisture permeability of the resin as a whole can be enhanced and the main chain is high. The strength also takes into account the waterproof property after coating and film formation.

WO 200210248-A1 uses a sulfonic acid group to replace a common carboxylic acid group to synthesize an aqueous PU. The sulfonic acid group can greatly improve the hydrophilicity of the aqueous PU, thereby lowering the structural content of the PEO, but still retaining high hydrophilicity and strength; Another advantage of the acid group is that it can reduce the use of solvents during synthesis. Therefore, such finished products are often used in cosmetics, shampoos and the like which are in direct contact with the human body. The water-absorbing PU has a water swelling and water absorbing effect.

In summary, in the prior art, PEO is the majority of the methods for synthesizing starting materials for aqueous PU. A patent using a PU resin containing no PEO and further introducing a PEO structure to form an aqueous polyurethane has not been proposed.

The invention provides a method for forming an aqueous polyurethane, comprising: (a) mixing 1.5 to 2.1 moles of diisocyanate with 1 mole of polyethylene glycol to make the end of the polyethylene glycol The functional group is modified from OH to NCO; (b) mixing 1 mole of diisocyanate, 0.1 to 0.9 moles of polyol, and 0.1 to 0.6 moles of hydrophilic group-containing glycol in an organic solvent The reaction is carried out to form a PU prepolymer, and the backbone of the PU prepolymer does not contain an ethylene glycol monomer; the hydrophilic group of the PU prepolymer is neutralized; the PU prepolymer is dispersed in water and reacted with a polyamine Adding the terminal functional group NCO of the PU prepolymer to NH ₂ ; and (c) adding the polyethylene glycol having a terminal functional group of NCO in the step (a) to the step (b) wherein the terminal functional group is NH ₂ The aqueous solution of the PU prepolymer is reacted to form an aqueous polyurethane.

The invention provides a method for forming an aqueous polyurethane, comprising: mixing 1.5 to 2.1 moles of diisocyanate with 1 mole of polyethylene glycol to make the terminal functional group of the polyethylene glycol OH is upgraded to NCO. If the molar fraction of the diisocyanate is less than the above range, it is difficult to form the terminal modified product of the first formula, and a large molecular weight oligomer (oligomer) is formed. On the other hand, if the mole fraction of the diisocyanate is above the above range, the unreacted diisocyanate will affect the subsequent reaction. The above reaction formula is as shown in the first formula:

In one embodiment of the invention, the polyethylene glycol has a molecular weight of between about 50 and 20,000, preferably between about 300 and 10,000, and more preferably between about 600 and 5,000. If the molecular weight of the polyethylene glycol is less than the above range, the moisture permeability of the product may be insufficient. If the molecular weight of the polyethylene glycol is larger than the above range, the product may be swollen and lose stability.

The diisocyanate in the first formula may be an aromatic diisocyanate, an aliphatic diisocyanate, or a combination thereof. In an embodiment of the invention, the diisocyanate comprises toluene diisocyanate (TDI), p-phenylene diisocyanate (PPDI), diisocyanate 4,4 ' - diphenylmethane ester (4,4 '-diphenylmethane diisocyanate, MDI) , diisocyanate, p, p' - diphenyl (p, p '-bisphenyl diisocyanate, BPDI), isophorone diisocyanate ( Isophorone diisocyanate, IPDI), 1,6-hexamethylene diisocynate (HDI), hydrogenated diphenylmethane-4, 4'-diisocyanate, H ₁₂ MDI), or a combination of the above. Further, the diisocyanate may further include other common substituents such as halogen, nitro, cyano, alkyl, alkoxy, haloalkyl, hydroxy, carboxy, decylamino, amine, or a combination thereof as long as it does not affect In the first formula, the terminal modification reaction of polyethylene glycol may be used.

Then, mixing 1 mole of diisocyanate, 0.1 to 0.9 moles of polyol, and 0.1 to 0.6 moles of hydrophilic group-containing glycol are reacted in an organic solvent, as in the second formula, to form a PU preform. a polymer, and the backbone of the PU prepolymer is free of ethylene glycol monomers. It is to be noted that the above polyol or the hydrophilic group-containing glycol does not contain a common ethylene glycol because ethylene glycol excessively swells or dissolves the PU prepolymer in the subsequent step of dispersing in water. It should be noted that the hydrophilic group-containing diol of the second formula has a hydrophilic group which is a carboxylic acid group, but may be another hydrophilic group such as a sulfite group or an ammonium group, and x in the second formula depends on The ratio of the hydrophilic group of the glycol. Similarly, the polyol in the second formula is butylene glycol, but other polyols may be as described below. In short, the second formula is for illustrative purposes only and is not intended to limit the invention.

In the case of using a quantitative diisocyanate, the higher the proportion of the polyol, the lower the proportion of the glycol containing the hydrophilic group, and vice versa. As a result, when the proportion of the polyol is too low and the proportion of the glycol containing the hydrophilic group is too high, the hydrophilicity of the PU prepolymer is too high and the gel is swelled. However, if the proportion of the polyol is too high and the proportion of the hydrophilic group-containing glycol is too low, the formed PU prepolymer has a hydrophilic group ratio which is too low, and it will not settle in water and aggregate and precipitate.

The type of the above diisocyanate is the same as described above, and will not be described herein. The main function of the above polyols is to react with diisocyanate to form a PU polymer. The polyol can also be used as a physical property modifier, and the hardness of the synthesized product is determined according to the molecular weight of the added polyol. In general, the low molecular weight polyol can make the hardness of the product higher. The above polyol may be a glycol, a polyol, an ether glycol, or a combination thereof. In an embodiment of the invention, the diol comprises propylene glycol, butylene glycol, pentanediol, hexanediol, cyclohexanediol, cyclohexyldimethanol (CHDM), octanediol, isoprene glycol ( Neopentyl glycol, NPG), trimethylpentanediol (TMPD), benzenedimethanol, benzenediol, toluol or bisphenol-A, butanediol-adipate copolymer (poly (butanediol-co-adipate)glycol, abbreviated as PBA), polytetramethylene glycol (PTMEG), hexanediol-co-adipate glycol (PHA), poly Polypropylene glycol (PPG), or a combination thereof. In an embodiment of the invention, the polyol comprises a polyester polyol, a polyether polyol, a polycarbonate polyol, a polycaprolactone polyol, a polyacrylate polyol, or a combination thereof, such as glycerol. , trimethylolpropane, pentaerythritol, benzenetriol, or a combination thereof. In an embodiment of the invention, the ether diols may be dipropylene glycol, tripropylene glycol, or a combination thereof.

The above-mentioned hydrophilic group-containing diol mainly functions by a hydrophilic functional group, so that the synthesized polymer can be effectively dispersed in water to become an aqueous PU. The above hydrophilic functional group includes carboxylate (COO ^- ), sulfite (SO ₃ ^2- ), or ammonium (NR ₄ ⁺ ), such as dimethylol propionic acid (DMPA), dihydroxyl Methyl butanoic acid (DMBA), bis(hydroxylethyl)amine or sodium 3-bis(hydroxyethyl)aminopropanesulfonate ).

Next, as shown in the formula 3, a base such as triethylamine (TEA) is added to neutralize the hydrophilic group of the PU prepolymer. In other embodiments, the base may be aqueous ammonia (NH ₄ OH), sodium hydroxide (NaOH), triethanolamine [(HOCH ₂ CH ₂ ) ₃ N], or the like, or a combination thereof.

Next, the PU prepolymer in the third formula is dispersed in water and reacted with a polyamine to reform the terminal functional group NCO of the PU prepolymer to NH ₂ as shown in the fourth formula. In Formula 4, the polyamine is ethylenediamine, but the polyamine may be other polyamines having 2 to 4 amine groups such as diethylenetriamine, triethylenetetramine, 2-methyl-1,5-pentane A compound of the formula H ₂ N-(CH ₂ ) _m —NH ₂ wherein m is an integer from 0 to 12, or a combination thereof.

After dispersing the PU prepolymer in water, a plurality of PU prepolymers will be tangled to each other to form a sphere of the formula 4 having a particle size of about several tens to several hundreds of nanometers (nm). . The above winding phenomenon can be referred to the paper Polyurethane Anionomers. II. Phase Inversion and Its Effect on Physical properties , Polymer , Vol. 34, 2776 (1992). The surface of the above sphere contains a hydrophilic group and an NCO group at the end of the PU prepolymer. Although water also reacts with the NCO group at the end of the PU prepolymer, the reaction rate is much lower than the reaction rate of the polyamine and the NCO functional group. The molar ratio of the NCO group at the end of the PU prepolymer to the polyamine is between 1:0.2 and 1:0.9. If the proportion of the polyamine is too low, the end of the PU prepolymer cannot be completely modified to NH ₂ . If the proportion of polyamine is too high, the unreacted polyamine will affect the subsequent reaction.

Finally, the product of the formula 1 is added to the aqueous solution of the formula 4 to carry out a reaction to form an aqueous polyurethane such as the formula 5.

In the formula 5, the polyethylene glycol having an NCO end tends to react with the two amine groups on the surface of the single sphere, and does not tend to react with the amine groups on the two spheres, respectively. The two spheres are crosslinked. This is because at a microscopic point, the distance between the two spheres is much larger than the distance between the two amine groups on a single sphere.

It should be noted that, after forming the intermediate of the third formula, the NCO of the surface of the sphere is modified to NH ₂ by a polyamine, and the NCO which is not reacted with the polyamine is also converted into NH by water. _2, followed in the NCO-terminated polyethylene glycol (NCO-PEO-NCO) polyethylene glycol grafted onto a spherical surface, since the surface of the spherical NH2 and NCO reactivity of ₂ to 100 times higher than that of water Above, the integrity of the grafting reaction can be ensured. The present invention does not suggest that the intermediate of the third formula (the spherical surface of the NCO) is directly reacted with the polyethylene glycol (NH ₂ -PEO-NH ₂ ) having a terminal of NH ₂ , as described in JP 2005060690-A. The technique of teaching, because the sphere is formed in water, before the addition of polyethylene glycol with NH ₂ at the end, the NCO on the surface of the sphere will react with water to become NH ₂ , and the stoichiometry of the subsequent grafting reaction is affected. ,incomplete. Although the present invention requires two steps to complete the so-called aqueous PU product after forming the intermediate of Formula 3, it is one step further than the step of JP 2005060690-A. However, the product of the present invention is superior to the product completed in the steps of JP 2005060690-A in terms of viscosity, tensile strength, and moisture permeability.

After the above steps, part of the organic solvent and water are removed by vacuum distillation or steam distillation to obtain an aqueous PU dispersion of <15% organic solvent, and the solid content of the aqueous PU is between 10~ 65% by weight.

The above and other objects, features, and advantages of the present invention will become more apparent and understood.

[Examples]

Example 1

In the reaction tank A, 209.68 g of PEO (polyethylene oxide) (Mn=2000), 26.1 g of acetone and 46.55 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours. Cool down for backup. In the reaction tank B, 42.63 g of dimethylol butionic acid (DMBA), 424.12 g of polytetramethylene glycol (PTMEG) (Mn=2000) and 52.17 g of acetone were used. Stir well in a nitrogen-protected reaction tank. When the above raw materials are in a homogeneous phase, 179.80 g of IPDI is added to the reaction tank. After reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 29.0 g is added. The triethylamine (TEA) was subjected to a neutralization reaction for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 2217 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted B. 12.95 g of ethylene diamine (EDA) was used for the chain extension reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain an aqueous PU dispersion having a solid content of 30% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the moisture permeability of the film was measured by the JIS L1099 A-2 method to be 1365 g/m ² ‧ day.

Example 2

In the reaction tank A, 27.21 g of PEO (Mn = 2000), 3.55 g of acetone and 6.04 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours, and then cooled to stand. In reaction tank B, 9.47 g of dimethylolbutanoic acid (DMBA), 108.68 g of polytetramethylene glycol (PTMEG) (Mn = 2000) and 14.19 g of acetone were stirred in a nitrogen-protected reaction vessel. Evenly, when the above raw materials are in a uniform phase, 48.69 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.51 g of triethylamine (TEA) is added. And reacting for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 1137.2 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 2.67 g for chain Prolong the reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 15% by weight, and a part was removed by distillation under reduced pressure. After the organic solvent and water, the solid content was increased to 21% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 2164 g/m ² ‧ day by the JIS L1099 A-2 method.

Example 3

In the reaction tank A, 17.49 g of PEO (Mn = 600), 2.44 g of acetone and 12.94 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours, and then cooled to stand. In reaction tank B, 9.48 g of dimethylolbutanoic acid (DMBA), 116.18 g of polytetramethylene glycol (PTMEG) (Mn = 2000) and 14.98 g of acetone were stirred in a nitrogen-protected reaction vessel. Evenly, when the above raw materials are in a uniform phase, 44.01 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.49 g of triethylamine (TEA) is added. And reacted for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 1138.9 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 2.69 g for chain Prolong the reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 15% by weight, and a part was removed by distillation under reduced pressure. After the organic solvent and water, the solid content was increased to 24% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 1193 g/m ² ‧ day by the method of JIS L1099 A-2.

Example 4

In the reaction tank A, 27.67 g of PEO (Mn = 1000), 3.04 g of acetone and 12.29 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours, and then cooled to stand. In the reaction tank B, 9.49 g of dimethylolbutanoic acid (DMBA), 93.22 g of polypropylene glycol (PPG) (Mn = 1000) and 14.43 g of acetone were uniformly stirred in a nitrogen-protected reaction vessel. When the above raw materials are in a uniform phase, 57.53 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.49 g of triethylamine (TEA) is added for neutralization reaction. 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 542.5 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 3.44 g for chain extension reaction. . After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 25% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 1127 g/m ² ‧ day by the method of JIS L1099 A-2.

Example 5

In the reaction tank A, 65.63 g of PEO (Mn = 1000), 8.55 g of N-methyl pyrrolidone (NMP) and 29.14 g of isophorone diisocyanate (IPDI) at 80 ° C After 4 hours of reaction, the temperature was lowered for use. In the reaction tank B, 8.30 g of dimethylolbutanoic acid (DMBA) and 67.17 g of poly(butanediol-co-adipate) (PBA) (Mn=2000) And 8.95g of NMP is uniformly stirred in a nitrogen-protected reaction tank. When the above raw materials are in a uniform phase, 31.85g of IPDI is added to the reaction tank, and after reacting at 80 ° C for 4 hours, the temperature of the reaction tank is lowered. Neutralization reaction was carried out by adding 5.76 g of triethylamine (TEA) to 50 ° C for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 1500 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by addition. 1.66 g of ethylenediamine (EDA) diluted with water was subjected to a chain extension reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 12% by weight, and a part was removed by distillation under reduced pressure. After the organic solvent and water, the solid content was increased to 20% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 2594 g/m ² ‧ day by the method of JIS L1099 A-2.

Example 6

In the reaction tank A, 22.06 g of PEO (Mn = 2000), 2.49 g of N-methylpyrrolidone (NMP) and 4.90 g of isophorone diisocyanate (IPDI) were reacted at 80 ° C for 4 hours, and then cooled. spare. In reaction tank B, 8.29 g of dimethylolbutanoic acid (DMBA), 119.27 g of polytetramethylene glycol (PTMEG, Mn=2000) and 14.96 g of NMP were uniformly stirred in a nitrogen-protected reaction vessel. When the above raw materials are in a uniform phase, 47.95 g of IPDI is added to the reaction tank, and after reacting at 80 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 5.64 g of triethylamine (TEA) is added for neutralization. The reaction was carried out for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 440 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 1.72 g for chain extension reaction. . After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain an aqueous PU dispersion having a solid content of 30% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 835 g/m ² ‧ day by the JIS L1099 A-2 method.

Example 7

In the reaction tank A, 15.35 g of PEO (Mn = 1000), 1.76 g of acetone and 6.82 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours, and then cooled to stand. In the reaction tank B, 9.48 g of dimethylolbutanoic acid (DMBA), 122.34 g of polytetramethylene glycol (PTMEG, Mn=2000) and 15.81 g of acetone were uniformly stirred in a nitrogen-protected reaction vessel. When the above raw materials are in a uniform phase, 46.15 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.48 g of triethylamine (TEA) is added for neutralization. The reaction was carried out for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 437.7 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 2.69 g for chain extension. reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain an aqueous PU dispersion having a solid content of 30% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 1440 g/m ² ‧ day by the JIS L1099 A-2 method.

Example 8

In the reaction tank A, 40.61 g of PEO (Mn = 1000), 15.0 g of acetone and 18.03 g of isophorone diisocyanate (IPDI) were reacted at 60 ° C for 4 hours, and then cooled to stand. In the reaction tank B, 9.48 g of dimethylolbutanoic acid (DMBA), 90.18 g of polytetramethylene glycol (PTMEG, Mn=2000) and 35.0 g of acetone were uniformly stirred in a nitrogen-protected reaction vessel. When the above raw materials are in a uniform phase, 42.37 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.46 g of triethylamine (TEA) is added for neutralization. The reaction was carried out for 20 minutes; the neutralized and hydrophilic group prepolymer was rapidly added to 1156.9 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 2.78 g for chain extension. reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 15% by weight, and a part was removed by distillation under reduced pressure. After the organic solvent and water, the solid content was increased to 23% by weight. The aqueous PU was cast by a petri dish to obtain a complete film, and the film was tested for moisture permeability of 3025 g/m ² ‧ day by the method of JIS L1099 A-2.

Example 9

In reaction tank A, 73.65g of JEFFAMINE After ED-2003, 73.64 g of acetone and 18.89 g of isophorone diisocyanate (IPDI) were reacted at 80 ° C for 4 hours, the amine group at the terminal was modified to NCO such as the formula 6.

In the reaction tank B, 9.50 g of dimethylolbutanoic acid (DMBA), 138.39 g of polytetramethylene glycol (PTMEG, Mn=2000) and 50.26 g of acetone were uniformly stirred in a nitrogen-protected reaction vessel. When the above raw materials are in a uniform phase, 53.08 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.48 g of triethylamine (TEA) is added for neutralization. The reaction was carried out for 20 minutes; 170 g of the prepolymerized and hydrophilic group was quickly added to 1155.9 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of water-diluted ethylenediamine (EDA) 3.4 g for chain Prolong the reaction. After the EDA was added and stirred for 30 minutes, the previously prepared mixture in the reaction tank A was further added, and stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 15% by weight, and the pH was 7.96. The viscosity was 43.5 cps, and the average particle size of the solid component in the solution was 162 nm. The aqueous PU was cast by a petri dish to obtain a complete film having a thickness of 0.060 mm. The film was tested for moisture permeability of 2727 g/m ² ‧day by a JIS L1099 A-2 method, tensile strength of 143 kg/cm ² , elongation of 699%, and 100% modulus of 19 kg/cm ² .

Comparative example 1

In the reaction tank, 9.48 g of dimethylolbutanoic acid (DMBA), 137.52 g of polytetramethylene glycol (PTMEG, Mn=2000) and 50 g of acetone were stirred uniformly in a nitrogen-protected reaction tank. When the above raw materials are in a uniform phase, 53.13 g of IPDI is added to the reaction tank, and after reacting at 60 ° C for 4 hours, the temperature of the reaction tank is lowered to 50 ° C and 6.49 g of triethylamine (TEA) is added for neutralization reaction 20 Minutes; 211.12 g of prepolymer which had been neutralized and had a hydrophilic group was rapidly added to 1163.7 g of deionized water at a stirring rate of 500 rpm for water dispersion, followed by the addition of 72.35 g of JEFFAMINE. ED-2003, stirring was continued at 50 ° C for 4 hours to obtain a solid PU dispersion having a solid content of 16 wt%, having a pH of 7.62, a viscosity of 20.5 cps, and an average particle diameter of the solid component in the solution of 149 nm. The aqueous PU was cast by a petri dish to obtain a complete film having a thickness of 0.061 mm. The film was tested for moisture permeability of 2058 g/m ² ‧day by a method of JIS L1099 A-2, tensile strength of 85 kg/cm ² , elongation of 916%, and 100% modulus of 11 kg/cm ² .

As described above, the two-step process product of the first modified and re-grafted product of the present invention (Example 9) is superior to the one-step process product of direct modification and grafting (Comparative Example 1).

While the invention has been described above in terms of several preferred embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

Claims (14)

A method for forming an aqueous polyurethane comprising: (a) mixing 1.5 to 2.1 moles of diisocyanate with 1 mole of polyethylene glycol to cause terminal functional groups of polyethylene glycol to be OH is modified to NCO; (b) mixing 1 mole of diisocyanate, 0.1 to 0.9 moles of polyol, and 0.1 to 0.6 moles of hydrophilic group-containing glycol in an organic solvent, Forming a PU prepolymer, and the backbone of the PU prepolymer is free of ethylene glycol monomer; neutralizing the hydrophilic group of the PU prepolymer; dispersing the PU prepolymer in water and reacting with a polyamine Carrying out a reaction to modify the terminal functional group NCO of the PU prepolymer to NH ₂ ; and (c) adding the polyethylene glycol having a terminal functional group of NCO in the step (a) to the terminal functional group in the step (b) An aqueous solution of the NH ₂ prepolymer of NH ₂ is reacted to form an aqueous polyurethane. The method for forming an aqueous polyurethane according to claim 1, wherein the diisocyanate comprises an aromatic diisocyanate, an aliphatic diisocyanate, or a combination thereof. The method for forming an aqueous polyurethane according to claim 2, wherein the diisocyanate comprises toluene diisocyanate, phenyl p-diisocyanate, diisocyanate-4, 4 '-Diphenylmethyl ester, diisocyanate-p,p'-biphenyl ester, 1,6-hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, or the above combination. The method for forming an aqueous polyurethane according to claim 1, wherein the polyol comprises a glycol, a polyol, an ether glycol, or a combination thereof. The method for forming an aqueous polyurethane according to claim 4, wherein the diol comprises propylene glycol, butylene glycol, pentanediol, hexanediol, cyclohexanediol, cyclohexyl dimethanol. , octanediol, isopentanediol, trimethylpentanediol, benzenedimethanol, benzenediol, toluenediol or bisphenol A, butanediol-adipate copolymer, polytetramethylene glycol, hexane An alcohol-adipic acid copolymer, polypropylene glycol, or a combination thereof. The method for forming an aqueous polyurethane according to claim 4, wherein the polyol comprises a polyester polyol, a polyether polyol, a polycarbonate polyol, a polycaprolactone polyol, Polyacrylate polyol, or a combination thereof. The method for forming an aqueous polyurethane according to claim 4, wherein the polyol comprises glycerin, trimethylolpropane, pentaerythritol, benzenetriol, or a combination thereof. The method for forming an aqueous polyurethane according to claim 4, wherein the ether glycol comprises dipropylene glycol, tripropylene glycol, or a combination thereof. The method for forming an aqueous polyurethane according to claim 1, wherein the hydrophilic group-containing diol has a hydrophilic group including a carboxylate (COO ^- ) or a sulfite (SO ₃ ^-2 ). Or ammonium (NR ₄ ⁺ ). The method for forming an aqueous polyurethane according to claim 1, wherein the hydrophilic group-containing glycol comprises dimethylolpropionic acid, dimethylolbutanoic acid, and bis(hydroxyethyl) An amine, sodium 3-bis(hydroxyethyl)aminopropane sulfonate, or a combination thereof. The method for forming an aqueous polyurethane according to claim 1, wherein the polyamine contains 2-4 amine groups, including ethylenediamine, diethylenetriamine, triethylenetetramine, 2- Methyl-1,5-pentanediamine, a compound of the formula H ₂ N-(CH ₂ ) _m -NH ₂ wherein m is an integer from 0 to 12, or a combination thereof. The method for forming an aqueous polyurethane according to claim 1, wherein the polyethylene glycol having the terminal modified to NCO has a weight molecular weight of between about 50 and 20,000. The method for forming an aqueous polyurethane according to claim 1, wherein the polyethylene glycol having the terminal modified to NCO has a weight molecular weight of about 300 to 10,000. The method for forming an aqueous polyurethane according to claim 1, wherein the polyethylene glycol having the terminal modified to NCO has a weight molecular weight of between about 600 and 5,000.