KR20030066253A - Development of adhesive by using amino acids - Google Patents

Abstract

PURPOSE: Provided is an adhesive which is useful for wood, electric and electronic fields, more particularly a non-toxic adhesive using normal amino acids or proteins and not comprising formaldehyde. CONSTITUTION: The adhesive is produced by reacting all amino acids or proteins with polymethylenebisphenyl isocyanate(PMDI). Alternatively, the adhesive is produced by reacting a compound having carboxylic acid and amino acid structures, which is obtained by hydrolyzing all amino acids or proteins, with polymethylenebisphenyl isocyanate(PMDI), wherein the equivalent ratio of the amino acid: PMDI is 3:1 to 1:3. The polymethylenebisphenyl isocyanate(PMDI) is a monomeric or polymeric compound comprising 1-5 equivalent(s) of isocyanate group and has the following structure(wherein n is 0-10).

Description

Development of adhesive by using amino acids

The present invention is wood, electrical, electronic adhesives, more specifically adhesives using common amino acids or proteins.

As interest in new materials is increasing in Korea, research institutes and schools are participating in the development of new materials, but research on structural materials based on special electrical and electronic materials is at a basic stage. At the same time, they are reluctant to disclose and transfer related technologies and are mostly know-how. Therefore, the accumulation of domestic technologies is essential for the development of excellent structural materials. The new adhesives and coatings using vegetable proteins to be developed by the research team are highly economical as new materials with high added value by using existing resources, and they are economically viable and can be considered to have great ripple effects.

In general, adhesives are excellent in mechanical, electrical insulation, adhesion, molding processability, and the like, and are selected and used in various ways depending on the purpose and purpose. In order to obtain such a functional resin, the chemical structure of a material used in the present invention is selectively changed to have characteristics of materials having excellent chemical, thermal, electrical, and physical properties. Due to the rapid growth and development of the petrochemical industry, plastics are used as industrial and consumer goods which are very useful for our daily life. Plastics are used for various applications such as packaging, wire coating, electric and electronic parts, and automobile parts because they are light and have excellent physical properties. However, in recent years, the importance of the environment is desperate, and plastic wastes generated after use have not been decomposed and are causing problems. However, compared to other materials (glass, metal, paper), plastics have the advantage of using less energy in the manufacturing process and lowering the amount of pollutant emissions. Therefore, plastics can be recycled more effectively than other materials. It is necessary to make efforts through the activation of.

Efforts to solve these pollution problems are emerging, such as the development of new degradable, disintegratable plastics, the method of separate collection of plastics, and the method of landfill with minimal volume. New degradable plastics are active in Europe and Japan, where they have a small area of ownership, but in reality, they are still less practical in terms of price and economy, and the disintegratable plastics currently used as garbage bags are simply invisible in our sight. I have a problem remaining. In case of landfill, it is difficult to secure landfill in case of small land area like Korea. Currently, the best way to prevent environmental pollution is to reduce waste, incinerate or recycle.

The development of materials using natural products is expected to greatly contribute to the high value added through environmental recycling and resource recycling. However, economic process development and application development are essential for the successful use of new materials. Development of new heat-curable adhesives using vegetable proteins is a very useful field in recognition of the importance of the environment. Especially, it can be applied to paper release agent, construction water repellent, textile waterproof coating, ink and adhesive used in stickers and adhesive tapes. In addition, it is possible to pursue high value-added by developing a coating (anti-fogging, hard coating, anti-static) having a functional.

Almost all materials used to make plastics are obtained through petrochemicals, the source of environmental pollution, and the reserves of crude oil are limited. One of the ways to overcome many of these problems is to make plastics using proteins, that is, amino acids, which are environmentally friendly and naturally biodegradable after use, thereby naturally solving the same problems as conventional plastics. Protein has been and will be used from ancient to modern times as an essential food culture in our daily lives.

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In the present invention, a revolutionary method to become a new electricity is to develop a new environmentally friendly adhesive using the first vegetable protein, and second to prepare a thermosetting adhesive applied to wood. Plant protein has a property of being naturally hydrolyzed because it has a peptide bond, and by using this hydrolyzable property, the chemical structure is modified to have a high functionality, that is, a hydrophobic property, to develop a material resistant to moisture. Focused. Since the present invention does not use any conventionally used formaldehyde, it is possible to exclude the strong toxicity harmful to the human body, and also to lower the economic cost.

The structure of the present invention is to develop an adhesive of a new property by forming an amide bond and a urea group at the same time by reacting the amino group and carboxylic acid group of the amino acid isocyanate group. This method can solve the problem of the adhesive strength of the conventional adhesive using only isocyanate and the expensive problem of urethane resin using isocyanate and polyol.

Most of the adhesives and coatings currently used for wood are made of petrochemical products. These materials have a problem that dioxin is generated by heat during combustion, and it is pointed out as a new environmental problem that harmful substances are eluted by polluting soil or water when waste is landfilled. The solution to this problem can be solved by using biodegradable materials obtained from nature. The use of formaldehyde adhesives, which are currently used in wooden houses and wooden floors in the timber industry, is a risk for carcinogens. For example, pallets made of plastic or formaldehyde adhesives are regulated for export using pallets. In the above results, although the adhesion decreased with increasing amino acid content, it showed that it was superior to the adhesive using only polymethylene bisphenyl isocyanate (PMDI) when less than 1.2 equivalents of amino acid was used for polymethylene bisphenyl isocyanate (PMDI). . Among the amino acids, glycine and asparagine were especially excellent, whereas serine and lysine with two amine groups showed a significant decrease. This is the result of reducing the reaction of the hydroxyl group of the wood by first reacting the isocyanate group of the polymethylene bisphenyl isocyanate (PMDI) and the highly reactive amine group. In the present results, a 1: 1 equivalent reaction with polymethylenebisphenylisocyanate (PMDI) can be said to reduce the adhesion and the amount of PMDI. Reactivity was shown in order of glycine> asparagine> serine> arginine> lysine, which is due to the inherent chemical structure of amino acids rather than solubility.

1. Manufacturing plywood for adhesion test

1.1. Veneer

The single piece for the manufacture of the adhesion test to measure the adhesive strength of plywood was used for the re-Kana Guinea hardwood Solarium (Canarium spp.) Of the air dry average specific gravity from 0.50 to 0.65. Single plates were sold by domestic plywood manufacturers. The plate thickness was 1.0mm on the front and back, and 2.4mm on the judgment plate, and it was cut into 200mm × 200mm to facilitate the plywood manufacturing test. The moisture content of the single plate was dried for 24 hours in a constant temperature dryer at 105 ℃, the moisture content of the plate was 6.7%, the middle plate was 6.1%.

1.2. Manufacture Plywood for Adhesion Test

Adhesion test plywood was prepared under the following conditions. Considering the amount of adhesive applied based on the existing adhesive test standard usage (120 ~ 170g / m2 (one side coating), standard forestry research guideline (forest) chapter 3, section 10, paragraph 2) and the moisture content of adhesive is less than 1% The coating amount was 150 g / m 2 (single side application) and applied with a roller.

Heat pressure was used by a manual hydraulic cold and heat press (Carver, model 2731, two-stage, made in the USA, ram ø 5.69cm). At this time, PP (polypropylene, melting point 170 ~ 180 ℃) film was inserted in consideration of the metal adhesion phenomenon of cowl and wood plate material.

Plywood Manufacturing Conditions

1.3 Moisture and Adhesion Test

The moisture content was measured after the test piece was cut into 100 mm x 100 mm. The water content was measured by Equation 1 by measuring the weight of the specimen after drying for 24 hours in a 105 ± 2 ℃ dryer.

The adhesive test piece was cut into a size of 75 mm × 25 mm to prepare an adhesive force specimen type B. The prepared specimens were measured and divided into condition test, water test, and repeated boiling test.

In the state test, the adhesion was measured at room temperature, and in the water resistance test, the specimen was immersed in warm water at 60 ± 3 ° C. for 3 hours, cooled in water at room temperature, and examined for adhesion in the wet state. In the repeated boiling test, the test pieces were boiled in boiling water for 4 hours, dried in a dryer at 60 ± 3 ° C. for 20 hours, and boiled again in boiling water for 4 hours, cooled in water at room temperature, and examined for adhesion in a wet state.

The adhesion test was carried out using a universal testing machine (Hunsfield H 50K-S, UK) and the crosshead ascent rate was measured at 2 mm / min. Adhesive force was computed by following formula 3.

Example 1.

Emulsification was facilitated using a surfactant in 16.14 g glycine in a 1000 mL three neck flask. The surfactant was added by 8 wt% of the adhesive amount and mixed for 10 minutes at a stirring speed of 1,000 rpm. 113 g of water was added to the mixture, and the wax emulsion was added during mixing. The wax emulsion was mixed for 30 minutes by adding 1wt% of the adhesive solids. After mixing, 136.88 g of polymethylenebisphenylisocyanate (PMDI) was added thereto, followed by stirring for 15 minutes at the same stirring speed and immediately used.

Example 2-6.

As shown in Table 1, the amount of glycine was carried out in the same manner as in Example 1 by mixing 1.2, 1.7, 2.2, 2.7 and 3.2 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Example 7.

Emulsification was facilitated using a surfactant in 18.94 g of asparagine in a 1000 mL three neck flask. The surfactant was added by 8 wt% of the adhesive amount and mixed for 10 minutes at a stirring speed of 1,000 rpm. 378.8 g of water was added to the mixture, and a wax emulsion was added at the time of mixing. The wax emulsion was mixed with 1 wt% of an adhesive solid for 30 minutes. After mixing, 136.82 g of polymethylene bisphenyl isocyanate (PMDI) was added and the mixture was stirred at the same stirring speed. It was used immediately after stirring for minutes.

Example 8-12.

As shown in Table 2, the amount of asparagine was mixed with 1.2, 1.7, 2.2, 2.7, and 3.2 equivalents of polymethylenebisphenylisocyanate (PMDI) in the same manner as in Example 7.

Example 13.

In a 1000 mL three-necked flask, 15.06 g of serine was used as a surfactant to facilitate emulsification. The surfactant was added by 8 wt% of the adhesive amount and mixed for 10 minutes at a stirring speed of 1,000 rpm. 301.2 g of water was added to the mixture, and a wax emulsion was added at the time of mixing. The wax emulsion was mixed for 30 minutes by adding 1 wt% of an adhesive solid. After mixing, 136.79 g of polymethylenebisphenylisocyanate (PMDI) was added thereto, followed by stirring for 15 minutes at the same stirring speed and immediately used.

Example 14-18.

As shown in Table 3, the amount of serine was mixed with 1.2, 1.7, 2.2, 2.7, and 3.2 equivalents of polymethylenebisphenylisocyanate (PMDI) in the same manner as in Example 13.

Example 19.

In a 1000 mL three-necked flask, 24.79 g of arginine was used as a surfactant to facilitate emulsification. The surfactant was added by 8 wt% of the adhesive amount and mixed for 10 minutes at a stirring speed of 1,000 rpm. 424.5 g of water was added to the mixture, and the wax emulsion was added at the time of mixing. The wax emulsion was mixed for 30 minutes by adding 1wt% of the adhesive solids. After mixing, 136.83 g of polymethylenebisphenylisocyanate (PMDI) was added thereto, followed by stirring for 15 minutes at the same stirring speed and immediately used.

Example 20-24.

As shown in Table 4, the amount of arginine was mixed with 1.2, 1.7, 2.2, 2.7, and 3.2 equivalents of polymethylenebisphenylisocyanate (PMDI) in the same manner as in Example 13.

Example 25.

Emulsification was facilitated by using a surfactant in 23.54 g of lysine in a 1000 mL three neck flask. The surfactant was added by 8 wt% of the adhesive amount and mixed for 10 minutes at a stirring speed of 1,000 rpm. 117.7 g of water was added to the mixture, and a wax emulsion was added during mixing. The wax emulsion was mixed for 30 minutes by adding 1 wt% of an adhesive solid. After mixing, 136.84 g of polymethylenebisphenylisocyanate (PMDI) was added thereto, followed by stirring for 15 minutes at the same stirring speed and immediately used.

Example 26-30.

As shown in Table 5, the amount of lysine was carried out in the same manner as in Example 13, by mixing 1.2, 1.7, 2.2, 2.7, and 3.2 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Comparative Example 1-3.

As shown in Table 1, the amount of glycine was carried out in the same manner as in Example 1 by mixing 3.7, 4.0, and 4.3 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Comparative Example 4-6.

As shown in Table 2, the amount of asparagine was mixed in the same manner as in Example 1 by mixing 3.7, 4.0, and 4.3 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Comparative Example 7-9.

As shown in Table 3, the amount of serine was carried out in the same manner as in Example 1 by mixing 3.7, 4.0, and 4.3 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Comparative Example 10-12.

As shown in Table 4, the amount of arginine was performed in the same manner as in Example 1 by mixing 3.7, 4.0, and 4.3 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Comparative Example 13-15.

As shown in Table 5, the amount of lysine was carried out in the same manner as in Example 1 by mixing 3.7, 4.0, 4,3 equivalents with respect to polymethylenebisphenylisocyanate (PMDI).

Table 1. Reaction conditions and reaction results of glycine

-MDI: Emulsifier: Amino Acid Solution = 100: 8: 100 Ratio

Table 2. Reaction Conditions and Result of Asparagine

Table 3. Reaction Condition and Result of Serine

Table 4. Reaction Conditions and Result of Arginine

Table 5. Reaction conditions and results of lysine

The present invention has developed commercially useful industrial materials adhesives using amino acids or proteins and polymethylenebisphenylisocyanates (PMDI). Synthesis of various adhesives is a useful method that can be used as a new environmentally friendly thermosetting material. In general, proteins have amino groups and carboxylic acids that can react, and also have amides that can decompose naturally and can be used as environmentally friendly materials. A feature of the present invention is the synthesis of environmentally friendly adhesives using existing amino acids and proteins and the production of non-toxic adhesives that do not contain any formaldehyde for wood in industrial materials.

Claims (5)

A compound obtained by reacting all amino acids or proteins with polymethylenebisphenylisocyanate (PMDI), characterized in that it is applied as a coating or adhesive for the wood industry. A compound obtained by reacting a carboxylic acid obtained by hydrolysis of all amino acids or proteins with a compound having an amino acid structure and polymethylenebisphenyl isocyanate (PMDI), and the equivalence ratio of amino acids and PMDI is in the range of 3: 1 to 1: 3. . The compounds obtained in claims 1 and 2 are compounds consisting of polyurethane or polyurea structures. Polymethylenebisphenylisocyanate (PMDI) used in claims 1 and 2 is a mono- or high molecular weight compound containing isocyanine group from 1 equivalent to 5 equivalents and its structure is as follows. n contains 0 to 10. All the compounds obtained above are used to make all the areas applied to industrial adhesives or coatings.