KR20040005448A - A method for preparing ethyl alcohol type polyurethane adhesive - Google Patents

Abstract

PURPOSE: Provided is a process for producing an ethylalcohol type polyurethane adhesive by dispersing a polyurethane adhesive in water and ethanol, which shortens drying time and improves adhesive force. CONSTITUTION: The process comprises the steps of: reacting 100pts.wt. of a polyol component comprising polyester and polyether polyol with 20-25pts.wt. of a diisocyanate component in a low boiling point polymerization solvent in the presence of a catalyst to prepare a prepolymer; neutralizing the prepolymer and then adding 2-5pts.wt. of a chain extender; dispersing it by using 50-150pts.wt. of the water and dropping 100-200pts.wt. of the ethanol and then performing a vacuum distillation to remove the polymerization solvent, wherein the weight ratio of the water and the ethanol is 20-70:30-80.

Description

A method for preparing ethyl alcohol type polyurethane adhesive

The present invention relates to a method for preparing a polyurethane adhesive, and more particularly, to prepare a polyurethane prepolymer by reacting a polyol component and a diisocyanate, and to disperse only with conventional water by dispersing with water and ethanol after neutralization and chain extension reaction. The present invention relates to a method for producing a polyurethane adhesive having a shorter drying time and improved adhesion as compared to a polyurethane water dispersion.

Up to now, almost all adhesives used in footwear and various industries have been used as one- or two-component solvent-type organic solvents that are harmful to humans. Ethyl acetate (EA), toluene, methyl ethyl ketone ( Polychloroprene (CR) or a polyurethane adhesive using a solvent such as methyl ethyl ketone (MEK) or the like was used.

However, as a part of increasing the worker's desire to improve the working environment and a method for improving the harmfulness to the human body, the trend is shifting to water solubilization or solvent-free.

Therefore, in recent years, adhesives for footwear have been replaced by water-dispersed polyurethane, and it is expected to rapidly change to a non-toxic solvent type in the future, but the aqueous type adhesives currently used are not good in wetting, and the drying time when the adhesive is used There is a problem that takes a long time.

Accordingly, the inventors of the present invention have made efforts to solve the problems described above, but the polyurethane adhesive is prepared using a conventional polyurethane adhesive composition, but after the chain extension reaction, specific water and ethanol that is harmless to the human body during the dispersion reaction. By using the ratio, it was found that a polyurethane adhesive having excellent wettability and a short drying time was completed, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a method for producing a water dispersible polyurethane adhesive using ethanol as a dispersant.

The present invention provides a polyurethane-based adhesive composition using a polyol component, a diisocyanate component, a chain extender, a catalyst, and a polymerization solvent, based on 100 parts by weight of the polyol component as a mixture of polyester and polyether polyol based on the total solids. 20-25 parts by weight of the diisocyanate component is reacted in the presence of a catalyst using a low boiling point polymerization solvent to prepare a prepolymer, and neutralizing the prepared prepolymer, followed by chain extension reaction by adding 2 to 5 parts by weight of a chain extender. And, after the chain extension reaction is dispersed using 50 to 150 parts by weight of water as a dispersant and dispersed while dropping 100 to 200 parts by weight of ethanol and distilled under reduced pressure to remove the polymerization solvent comprising a process for producing a polyurethane adhesive It features.

The present invention will be described in detail as follows.

In the present invention, in order to synthesize the polyurethane, the polyol and ionic monomer is reacted with diisocyanate, and the polyisocyanate (NCO) group is used in excess of the hydroxyl group (OH) to prepare the polyurethane prepolymer, followed by the chain extension reaction by adding a chain extender. To synthesize polyurethane. Water was used to aid dispersion and alcohol was added to synthesize polyurethane adhesives dispersed in water and alcohol.

As the polyol component used in the present invention, polyol components such as polyester polyol and polyether polyol are used. As the diisocyanate component, 1,6-hexamethylene diisocyanate (HDI) and 4,4'-dicyclohexyl methane di Isocyanate (H ₁₂ MDI) and the like.

The chain extender used for high molecular weight of the prepolymer in which the OH group is introduced may be used a compound having two or more reactors at its end, and specifically, for example, ethylene glycol, 2,2-dimethyl-1,3- Propanediol, 1,6-hexanediol, piperazine, 1,6-hexamethylenediamine and the like are used.

The polyol component is purified by distillation under reduced pressure at 100 to 110 ° C., and the polyol is added to a five-necked separate flask equipped with a stirrer and a cooler, and the mixture is stirred while heating at 80 to 85 ° C. for about 30 minutes. Next, 0.02 parts by weight of a catalyst (DBTDL: Dibutyl tin dilaurate) is added and stirred for 10 minutes, and then a predetermined amount of isocyanate is added to proceed with the reaction. After the reaction is completed, the temperature is lowered to room temperature to synthesize a polyurethane prepolymer having isocyanates at both ends. A certain amount of acetone, a solvent, was added to adjust the viscosity throughout the synthesis.

When the reactant reaches 25 to 30 ° C., neutralize using a fixed amount of TEA (Triethylamine) diluted in acetone as a neutralizing agent and stir for about 40 minutes. The chain extender is added to the neutralized polyurethane prepolymer and subjected to chain extension reaction for 2 hours. Thereafter, distilled water is slowly added dropwise to emulsify, and then alcohol is used to prepare a complete polyurethane dispersion. The amount of water used is 50 to 150 parts by weight, at which time the stability of the polyurethane adhesive is lowered if it is less than 50 parts by weight, and if it exceeds 150 parts by weight, rapid drying effect by ethanol cannot be expected. The amount of ethanol to be used is 100 to 200 parts by weight, wherein when the amount of ethanol used is less than 100 parts by weight, the rapid drying effect and the wettability by ethanol cannot be expected, and when it exceeds 200 parts by weight, the polyurethane adhesive lacks stability. That is, distilled water is added to adjust the amount of water to be 20 to 70% in the solvent contained in the final adhesive. If the amount of water is less than 20%, the stability is poor, if more than 70% it is difficult to expect fast drying and wetting by alcohol. Thereafter, the solvent is extracted at 40 to 45 ° C. under reduced pressure or normal pressure to obtain a polyurethane adhesive dispersed in water and alcohol. The concentration of the finally prepared polyurethane adhesive is adjusted to 50% and the viscosity is adjusted using other additives and the like.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

As shown in Table 1, 47.6 parts by weight of PBA 3791, which is a polyester polyol, 40.3 parts by weight of CAPA 240, which is a polycaprolactonediol, and 12.1 parts by weight of P-205BA, which is an ionic monomer, were heated to 80 to 85 ° C. Thereafter, 0.02 parts by weight of catalyst (DBTDL) was added, followed by stirring for 10 minutes, followed by addition of 22 parts by weight of 4,4'-dicyclohexyl methane diisocyanate (H ₁₂ MDI), followed by reaction for about 4 hours. The prepolymer was prepared by lowering the temperature. Acetone was added in an amount of 150 to 200 parts by weight to adjust the viscosity throughout the synthesis.

When the reaction product is at room temperature, neutralize the mixture by using 2.5 parts by weight of TEA diluted to 10% in acetone, and stirring the solution for about 40 minutes to complete the neutralization. Then, 2.2 parts by weight of 1.6-HDA, a chain extender, is used in the prepared polyurethane prepolymer. Chain reaction was carried out over 2 hours.

After chain extension, 50 parts by weight of distilled water is slowly dropped to emulsify the alcohol well, and after emulsification to some extent, 200 parts by weight of alcohol is added to synthesize polyurethane dispersed in water and alcohol, and acetone is removed by distillation under reduced pressure. To prepare a milky polyurethane dispersion of 50% solid content.

Example 2

To prepare a polyurethane dispersion in the same manner as in Example 1, 100 parts by weight and 150 parts by weight of water and ethanol, respectively, used after the chain extension reaction were used, and each component is shown in Table 1 below.

Example 3

The polyurethane dispersion was prepared in the same manner as in Example 1, but 150 parts by weight and 100 parts by weight of water and ethanol, respectively, used after the chain extension reaction, were shown in Table 1 below.

Comparative example

As shown in Table 1, 47.6 parts by weight of PBA 3791 (average molecular weight: 3791), which is a polyester polyol, 40.3 parts by weight of CAPA 240 (average molecular weight: 4000), which is a polycaprolactonediol, and P-205BA (average, which is an ionic monomer) Molecular weight: 500) 12.1 parts by weight of the reactor was heated to 80 to 85 ° C., then 0.02 parts by weight of catalyst (DBTDL) was added and stirred for 10 minutes, followed by 22 parts by weight of 4,4′-dicyclohexyl methane. After adding a diisocyanate (H ₁₂ MDI) and proceeding the reaction for about 4 hours to prepare a prepolymer by lowering the temperature. A certain amount of acetone, which does not react with isocyanates or polyols, is added to control the viscosity throughout the synthesis.

When the reactant is at room temperature, 2.5 parts by weight of TEA diluted in acetone is neutralized and stirred for about 40 minutes. The chain extension reaction was carried out over 2 hours using 1.6 parts by weight of 1.6-HDA in the neutralized polyurethane prepolymer. After chain extension, 250 parts by weight of distilled water is slowly added dropwise to emulsify the synthetic polyurethane, and the solvent is removed by distillation under reduced pressure to prepare a milky polyurethane dispersion having a solid content of 50%.

Ingredient Ingredients (parts by weight) Example 1 Example 2 Example 3 Comparative example Polyol Polyester Polyol ¹⁾ 47.6 47.6 47.6 47.6 Polycaprolactone diol ²⁾ 40.3 40.3 40.3 40.3 Ionic monomer ³⁾ 12.1 12.1 12.1 12.1 Diisocyanate ⁴⁾ 22 22 22 22 Neutralizer ⁵⁾ 2.5 2.5 2.5 2.5 Chain extension agent ⁶⁾ 2.2 2.2 2.2 2.2 Catalyst ⁷⁾ 0.02 0.02 0.02 0.02 Dispersant water 50 100 150 250 Ethanol ⁸⁾ 200 150 100 - 1) PBA 3791 (average molecular weight: 3791), Aekyung Chemistry 2) CAPA 240 (average molecular weight: 4000), Solvay 3) P-205BA (average molecular weight: 500), Daicel4) H ₁₂ MDI, aldrich5) TEA, aldrich6) 1, 6-HDA, aldrich 7) DBTDL, Fluka 8) ethanol, aldrich

Experimental Example

The polyurethane water dispersions prepared in Examples 1 to 3 and Comparative Examples were characterized by the following method, and the results are shown in Table 2 below.

<Adhesive specimen preparation>

The rubber adherend used in this experiment was polished with abrasive stone and washed with toluene. D-PLY 007, a pretreatment agent for polyurethane adhesives, was applied to rubber and dried at 60 ° C. for 5 minutes. The adhesive was applied and dried at 60 ° C. for 4 minutes and then pressed to prepare an adhesive specimen. Foam (EVA foam, specific gravity 0.15 to 0.3) adherend was washed with D-PLY PC-3 (Dynamic NSC). After completely drying, D-PLY P-5-2, a UV pretreatment agent, was applied and then passed through UV (200-400 nm) twice. Thereafter, adhesives prepared according to Examples 1 to 3 and Comparative Examples were applied, dried at 65 ° C. for 4 minutes, and pressed to prepare an adhesive specimen.

<Adhesion evaluation>

Polyurethane adhesive was applied on the prepared rubber and foam (EVA foam, specific gravity 0.15 to 0.3) adherend and pressed, and after 5 minutes, the adhesive strength was evaluated and the initial adhesive strength was measured. After 24 hours, the adhesive strength was evaluated. .

division Example 1 Example 2 Example 3 Comparative example Properties Initial Adhesion (kgf / cm) 3.5 3.0 2.7 2.5 Adhesion Improvement Effect (%) 140 120 108 100 Adhesive force (kgf / cm) 4.0 3.9 3.7 3.5 Adhesion Improvement Effect (%) 114 111 106 100 Drying time ^* 3 minutes 4 minutes 4 minutes 30 seconds 8 minutes Substrate Rubber / Foam (EVA Foam) Drying was carried out in a convection oven at 60 ° C.

As shown in Table 2, the polyurethane adhesive prepared according to the present invention is superior to the initial adhesive strength and state adhesive strength than the comparative example dispersed only in water, it can be seen that the drying time is reduced by about 2 times.

As described above, according to the production method of the present invention, by dispersing the polyurethane adhesive as water and ethanol, organic solvents are not used to remove harmful effects to the human body, and as a result, the working environment can be improved, Improved adhesiveness improves the adhesive strength and can shorten the drying time to produce a polyurethane adhesive to increase the productivity in the bonding process.

Claims (3)

In preparing a polyurethane-based adhesive composition using a polyol component and a diisocyanate component, a chain extender, a catalyst and a polymerization solvent, Preparing a prepolymer by reacting 20 to 25 parts by weight of the diisocyanate component in the presence of a catalyst using a low boiling point polymerization solvent with respect to 100 parts by weight of the polyol component as a mixture of polyester and polyether polyol with respect to the total solids; Neutralizing the prepared prepolymer and then adding 2 to 5 parts by weight of a chain extender to perform a chain extension reaction; After the chain extension reaction is dispersed using 50 to 150 parts by weight of water as a dispersant, and then dispersed while dropping 100 to 200 parts by weight of ethanol and distilled under reduced pressure to remove the polymerization solvent, characterized in that it comprises a polyurethane adhesive manufacturing method . The method of claim 1, wherein the water and ethanol are in the range of 20 to 70:30 to 80 weight ratio. Polyurethane adhesive, characterized in that produced by the method of claim 1 to 2.