KR100401184B1 - Biodegradable polyurethane capsules and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a polyurethane biodegradable capsule which is a raw material of a foam molded article and a method for manufacturing the same, wherein the polyurethane biodegradable capsule according to the present invention is a powder made of a biodegradable material; A first coating layer formed on the surface of the powder and made of calcium alginate gel; And a second coating layer formed on the surface of the first coating layer and made of a expandable polyurethane resin. Products molded from the polyurethane biodegradable capsules of the present invention have a membrane made of calcium alginate gel, which is biodegradable and has excellent elasticity. By biodegradation. Therefore, it is possible to minimize the problems of soil, air, marine pollution due to landfill, incineration, etc. of conventional polyurethane foam molded product waste.

Description

Polyurethane biodegradable capsule and its manufacturing method

The present invention relates to a polyurethane biodegradable capsule which is a raw material of a foamed molded product, and a method for manufacturing the same. More specifically, the present invention relates to a biodegradable calcium alginate gel membrane which is not only excellent in physical properties such as impact resistance and fracture resistance, but also a natural substance. The present invention relates to a raw material capsule of a polyurethane foamed molded product and a method for manufacturing the same, which can be minimized by soil, air, and marine pollution caused by landfilling, incineration, etc. by being decomposed by natural microorganisms after a predetermined period.

Synthetic polymers, represented by plastics, are one of the important materials to lead a convenient and comfortable modern life together with metals and ceramics. Such synthetic polymer products are used in various industries, such as household goods, construction, medical, agriculture, the amount of use is increasing significantly. However, unlike natural polymers, most synthetic polymers are not easily decomposed, so the disposal and management of waste products made of these synthetic polymers has become a major social problem in many countries around the world.

Particularly, polyurethane foam molded products are products formed after reacting polyol and isocyanate in the presence of a foaming agent such as CFC, reaction catalyst, foam stabilizer, etc. to manufacture polyurethane foam. Or it is widely used as insulation materials for vehicles, insulation structures, etc. Polyurethane foam molded waste products are designated wastes, which is difficult to regulate, and the wastes of these products are too large to collect. Holding In addition, these collected wastes are disposed of by landfill or incineration, which not only requires extensive space, but also slows down the decomposition, contaminating the soil and causing these wastes to enter the ocean and become the main culprit of marine pollution. In addition, the incineration process causes the emission of toxic gas to cause air pollution and the problem of corrosion of the incineration plant.

Therefore, the United States, Italy, and other countries have passed legislation to restrict the use of such synthetic polymer products, which have a short service life and are not required for durability, and to be replaced with degradable materials.

As a part of the research to solve the treatment problems of the synthetic polymer waste products, a method of recycling the waste polyurethane foam has been proposed.

For example, U.S. Patent No. 5,451,376 discloses a mechanical method for finely crushing waste polyurethane foam to be used as a filler for injection or extrusion molding products or as an enhancer for polyurethane-based adhesives, or as appropriately crushed and compressed into a re-adhesive foam. A regeneration method is disclosed. In this method, since the polyurethane used as the filler is a foam and a thermosetting polymer, there is no interaction between the interfaces with the matrix resin used in the manufacture of injection or extrusion molded products, and thus the mechanical properties of the molded products prepared by blending the polyurethane are remarkable. There is a problem of deterioration, which makes it difficult to commercialize. In addition, U.S. Patent No. 4,159,972 discloses a chemical regeneration method for depolymerizing polyurethane using various solvents, but the conversion rate of the reaction is low, which is disadvantageous in terms of economics. In addition, a method of recovering waste heat by incineration with municipal solid waste has been proposed, focusing on energy recovery rather than regeneration of polyurethane foam.

However, the recycling method of such a foamed molded product is not economical due to excessive processing cost, and finally, it must be treated by a conventional method such as landfill, and thus cannot be a method for ultimately solving an environmental problem.

Therefore, the technical problem to be solved by the present invention is to solve the above problems, not only excellent in physical properties such as impact resistance, fracture resistance, etc., but also provided with a biodegradable calcium alginate gel gel film which is a natural substance, collapsed by natural microorganisms after a predetermined period of time. Therefore, to provide a raw material capsule of the polyurethane foam molded products that can solve the problems of soil, air, marine pollution caused by landfill, incineration and the like and a method of manufacturing the same.

Another technical problem to be achieved by the present invention is to provide a method for producing the polyurethane biodegradable capsule.

In order to achieve the above technical problem, the present invention is a powder made of a biodegradable material; A first coating layer formed on the surface of the powder and made of calcium alginate gel; And a second coating layer formed on the surface of the first coating layer and made of a expandable polyurethane resin.

In the polyurethane biodegradable capsule according to the present invention, grains may be used as the biodegradable powder forming the core portion, and in particular, corn or foamed corn powder is preferably used.

In addition, in order to achieve the above technical problem, the present invention includes a capsule containing carbon dioxide and calcium alginate gel therein; And a coating layer formed on the surface of the capsule and made of a expandable polyurethane resin.

In addition, in order to achieve the above technical problem, the present invention is a powder made of a biodegradable material; Calcium alginate gel coating layer formed on the surface of the powder; And an outer layer formed on the surface of the coating layer and made of an expandable polyurethane resin produced by addition polymerization of an active hydroxyl group and an isocyanate of calcium alginate gel to provide a polyurethane biodegradable capsule.

In addition, in order to achieve the above technical problem, the capsule containing carbon dioxide inside and made of calcium alginate gel; And an outer layer formed on the surface of the capsule and made of an expandable polyurethane resin produced by addition polymerization of an active hydroxyl group and an isocyanate of calcium alginate gel to provide a polyurethane biodegradable capsule. .

In order to achieve the above technical problem, the present invention provides a capsule containing a) a first coating layer made of calcium alginate gel on the surface of the powder by dropping a solution of sodium alginate in which a powder made of a biodegradable substance is dispersed in an aqueous solution of calcium chloride. Manufacturing; b) separating the capsule; And c) forming a second coating layer made of a expandable polyurethane resin on the surface of the separated capsule.

In the method for producing a polyurethane biodegradable capsule of the present invention, the step of forming a second coating layer made of the expandable polyurethane resin of step c), the polyol and isocyanate are added to the separated capsule and the blowing agent and the reaction catalyst present The reaction may be carried out under a step or after the polyol is coated on the separated capsule surface and then reacted with isocyanate in the presence of a blowing agent and a reaction catalyst.

In addition, in order to achieve the above another technical problem, the present invention comprises the steps of: a) mixing the aqueous sodium alginate and sodium bicarbonate solution with calcium chloride aqueous solution dropwise to form a capsule of calcium alginate gel containing carbon dioxide therein: b) the Separating the capsules; And c) forming a coating layer made of a expandable polyurethane resin on the surface of the separated capsule.

Hereinafter, a polyurethane biodegradable capsule and a manufacturing method thereof according to the present invention will be described in detail.

Generally, degradable polymers are classified into biodegradable, hydrolyzable, photodegradable and oxidatively degradable polymers according to their decomposition process. According to the US ASTM definition, a biodegradable polymer refers to a polymer that is degraded by the action of microorganisms such as bacteria, fungi and algae, and a hydrolyzable polymer is a polymer that is degraded by hydrolysis. In addition, the photodegradable polymer refers to a polymer that is decomposed by natural light, especially ultraviolet light, the oxidatively decomposable polymer is a polymer that is decomposed by oxidation. On the other hand, the Japan Biodegradable Plastics Research Society defines biodegradable polymers as macromolecules that are decomposed into low molecular materials that do not adversely affect the environment due to the involvement of microorganisms in nature.

Therefore, in order to become a biodegradable polymer, natural microorganisms are involved and completely decomposed into water and carbon dioxide and circulated in the natural environment so as not to cause any environmental problems. Microorganisms have specific substrate specificities. That is, since it exhibits high reactivity to a compound having a specific molecular structure, even if a synthetic polymer having biodegradability is designed, it may not be smoothly decomposed by microorganisms existing in nature. Therefore, in the present invention, by using a biodegradable powder such as corn powder or alginic acid, which is a natural polymer derived from plants, as a core part of the expandable polyurethane-based resin, the expanded molded product is readily decomposed by natural microorganisms after a predetermined period of time. Polyurethane biodegradable capsules can be prepared.

Polyurethane biodegradable capsule according to an embodiment of the present invention is a powder made of a biodegradable material; A first coating layer formed on the surface of the powder and made of calcium alginate gel; And a second coating layer formed on the surface of the first coating layer and made of a expandable polyurethane resin.

The powder made of biodegradable substance and the calcium alginate gel are decomposed by the microorganism after a predetermined time, thereby disintegrating the polyurethane resin coating layer formed on the surface thereof. Therefore, it is possible to improve the disposal efficiency of the landfill of the waste molded product made of such a biodegradable capsule. The biodegradable powder that forms the core of the biodegradable capsule can be biodegradable and any material can be used as long as the polystyrene-based resin can be coated on its surface, but it is preferable to use grain such as inexpensive corn powder or foamed corn powder. Do.

Alginic acid, a raw material for preparing calcium alginate gels coated on the surface of biodegradable powders, can be obtained in large quantities from brown algae in marine plants. Alginic acid is a linear copolymer in which a block of manuronic acid (M) unit, a block of guronic acid (G) unit, and a block of MG unit in the middle thereof are composed of 1,4-glycoside, and its molecular weight is about 20,000 to 200,000. Alginic acid reacts with metal ions such as calcium to form a gel. The resulting gel does not melt upon heating and can be heat treated. In particular, since the flexible gel is formed by the M block, it is possible to change the properties of the gel in accordance with the ratio of M / G. In this gelation process, the enzymatic activity can be controlled by encapsulation by adding enzymes, microorganisms, animal cells, and plant cells. As such, the calcium alginate gel coating layer formed on the surface of the biodegradable powder is not only excellent in biodegradability, but also has good elasticity, thereby further improving the impact resistance and fracture resistance properties of the expandable polystyrene biodegradable capsule.

In addition, the expandable polyurethane resin which is a raw material of the second coating layer of the biodegradable capsule according to an embodiment of the present invention may be coated on the surface of the first coating layer made of calcium alginate gel, and various types of poly known to those skilled in the art. Urethane resin can be used. Polyurethane resins have excellent thermal insulation properties, which give the final foamed polyurethane molded products especially thermal insulation properties.

Looking at the manufacturing method of the polyurethane biodegradable capsule according to the above embodiment, first, the aqueous solution of sodium alginate in which the powder having the same biodegradation performance as the foamed corn powder is dispersed is added dropwise to the calcium chloride aqueous solution while stirring with a stirrer. To prepare a capsule in which a first coating layer made of calcium alginate gel was formed. The particle diameter of the capsule formed at this time can be adjusted according to the stirring speed. That is, if the stirring speed is fast, the particle size is small, and if the stirring speed is slow, a capsule having a larger particle size is formed, and it is preferable to stir at a speed of 50 to 150 rpm. Subsequently, the capsules are filtered using a filter or centrifuge, and then dried, and the polyols and isocyanates are added to the separated capsules and reacted in the presence of a blowing agent and a reaction catalyst, or the polyols are separated into the capsules under a blowing agent and a reaction catalyst. After the reaction to form a polyol coating layer, isocyanate is added dropwise to form a second coating layer made of expandable polyurethane resin on the capsule surface. At this time, the blowing agent or reaction catalyst can be used as long as it is commonly used in the production of polyurethane foam, for example, chlorofluorocarbons (CFC-11, CFC-12, etc.), HCFC-123, HCFC-141b In addition to HFC-134a and HFC-152a, hydrochlorofluorocarbons, hydrofluorocarbons, etc. can be used, and a triethylamine, diethylethanolamine potassium hydroxide, etc. can be used as a catalyst.

Polyurethane biodegradable capsule according to another embodiment of the present invention is a capsule containing carbon dioxide therein and made of calcium alginate gel; And a coating layer formed on the surface of the capsule and made of a expandable polyurethane resin. Products molded from such biodegradable capsules are filled with gas inside the capsule to provide excellent thermal insulation, impact resistance and elasticity, as well as excellent biodegradability. Polyurethane biodegradable capsule production method according to another embodiment of the present invention is as follows.

First, a mixture of sodium alginate and sodium bicarbonate solution is added dropwise to the aqueous calcium chloride solution to form an elastic capsule made of porous calcium alginate gel containing carbon dioxide therein. The particle diameter of the capsule formed at this time can be adjusted according to the stirring speed. In other words, if the stirring speed is fast, the particle size is small, and if the stirring speed is slow, a capsule having a larger particle size is formed. Subsequently, the capsules were filtered using a filter or centrifugal separator and then dried, and reacted in the presence of a blowing agent and a reaction catalyst as described above, or a polyol was reacted in the separated capsules under a blowing agent and a reaction catalyst to form a polyol coating layer. After the addition of isocyanate is added dropwise to form a coating layer made of expandable polyurethane resin on the capsule surface.

As such, when the polyurethane biodegradable capsule according to the present invention is put into a predetermined mold and molded while controlling the foaming pressure, a foamed molded article having a desired shape having various physical properties can be obtained.

Polyurethane biodegradable capsules according to another embodiment of the present invention capsules formed on the powder surface of the calcium alginate gel coating layer made of a biodegradable material; Or capsules containing carbon dioxide therein and made of calcium alginate gel; And an outer layer formed on the surface of the capsule and made of an expandable polyurethane resin produced by addition polymerization of an active hydroxyl group and an isocyanate of calcium alginate gel.

Since the capsule made of calcium alginate gel contains a large amount of active hydroxyl groups, when reacted with isocyanate under a reaction catalyst, the active hydroxyl group and isocyanate on the capsule surface are additionally polymerized to form an outer layer made of polyurethane on the capsule surface.

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Preparation Example of Calcium Alginate Gel Coating Layer

Preparation Example 1

At room temperature, 4.0 g of sodium alginate and 50.0 g of expanded corn powder were added dropwise to a mixed solution of 20.0 ml of acetone and 80.0 ml of water, followed by stirring for 1 hour. Subsequently, the agitated solution was added dropwise to a saturated calcium chloride solution at 60 ° C. while stirring at 100 rpm to prepare 150.0 g of a biodegradable porous capsule coated with calcium alginate gel on the surface of corn powder.

Preparation Example 2

At room temperature, 4.0 g of sodium alginate, 50.0 g of foamed corn powder, and 1 g of sodium bicarbonate were added dropwise to 100.0 ml of water, followed by stirring for 1 hour. This agitated solution was then added dropwise to a saturated calcium chloride solution at 35 ° C. with stirring at 100 rpm to prepare 155.0 g of a biodegradable porous capsule coated with calcium alginate gel on the surface of corn powder.

Preparation Example 3

At room temperature, 4.0 g of sodium alginate and 1 g of sodium bicarbonate were added dropwise to 100.0 ml of water, followed by stirring for 1 hour. Subsequently, this stirred mixture was added dropwise to a saturated calcium chloride solution at 30 ° C. while stirring at 100 rpm to prepare 100 g of an elastic capsule containing carbon dioxide therein and made of calcium alginate gel.

The physical properties of the capsules according to Preparation Examples 1 to 3 were measured according to the following methods and shown in Table 1.

<Measurement of physical properties>

Biodegradability: Measured according to the guidelines of OECD 301, C, MITI TEST (II) (1992).

Capsule Average Diameter (mm) Thickness of Calcium Alginate Gel Coating Layer (mm) Biodegradability (%) Preparation Example 1 2 0.008 97 Preparation Example 2 2 0.011 98 Preparation Example 3 2 0.010 99

Referring to Table 1, the capsules according to Preparation Examples 1 to 3 were very excellent in biodegradability, and it was shown that a coating layer having a uniform thickness was formed.

Example 1

20.0 g of the porous capsule prepared in Preparation Example 1, 0.1 ml of triethylamine, 5.0 ml of ethylene glycol, and 10.0 ml of polyol were mixed and stirred at room temperature for 30 minutes. 5.0 ml of isocyanate was added dropwise to this mixed solution to carry out addition polymerization to obtain 30.0 g of a capsule coated with a polyurethane resin on the surface of the porous capsule. The resultant was put into a foam molding machine and molded to prepare a foamed polyurethane biodegradable molded product.

Example 2

20.0 g of the porous capsule prepared in Preparation Example 1, 0.1 ml of triethylamine, and 10.0 ml of ethylene glycol were mixed and stirred at room temperature for 30 minutes. 5.0 ml of isocyanate was added dropwise to this mixed solution to carry out addition polymerization to obtain 30.0 g of a capsule having a polyurethane resin bonded to the surface of the porous capsule. The resultant was put into a foam molding machine and molded to prepare a foamed polyurethane biodegradable molded product.

The physical properties of the molded articles according to Examples 1 and 2 were measured according to the following method and shown in Table 2.

<Measurement of physical properties>

Specific gravity: measured according to ASTM D 792.

Biodegradability: Measured according to the guidelines of OECD 301, C, MITI TEST (II) (1992).

Tensile strength: measured according to ASTM D 412.

Tensile Elongation: Measured according to ASTM D 412.

importance Biodegradability (%) Tensile strength (psi) Tensile Elongation (%) Example 1 0.04 90 1.8 150 Example 2 0.04 89 2.1 200

Referring to Table 2, the molded article made of polyurethane biodegradable capsules according to Examples 1 to 2 was found to be excellent in biodegradability and light weight, and good physical properties such as tensile strength.

As described above, the product molded into the biodegradable capsules according to the present invention can be used in various ways, such as electric refrigerators, freezers, heat insulating panels, ships or vehicles, heat insulating materials, and the like, and after a predetermined period of time. Since the biodegradable material inside the polyurethane resin is biodegraded by microorganisms in nature, problems of soil, air, and marine pollution due to landfill, incineration, etc. of conventional foamed molded product waste can be minimized.

Claims (10)

Powder made of biodegradable material; A first coating layer formed on the surface of the powder and made of calcium alginate gel; And Polyurethane biodegradable capsule comprising a; a second coating layer formed on the surface of the first coating layer and made of a expandable polyurethane resin. The polyurethane biodegradable capsule of claim 1, wherein the powder is a grain powder. The polyurethane biodegradable capsule according to claim 2, wherein the grain powder is corn or foamed corn powder. a) preparing a capsule in which a first coating layer made of calcium alginate gel is formed on the surface of the powder by stirring and dropping an aqueous sodium alginate solution in which a powder made of a biodegradable substance is dispersed in an aqueous solution of calcium chloride; b) separating the capsule; And c) forming a second coating layer made of a expandable polyurethane resin on the surface of the separated capsule; manufacturing method of a polyurethane biodegradable capsule comprising a. The method of claim 4, wherein the forming of the second coating layer made of the expandable polyurethane resin of step c), Polyol and isocyanate are added to the separated capsule, and the method of producing a polyurethane biodegradable capsule, characterized in that consisting of reacting in the presence of a blowing agent and a reaction catalyst. The method of claim 4, wherein the forming of the second coating layer made of the expandable polyurethane resin of step c), After coating the polyol on the separated capsule surface, a method for producing a polyurethane biodegradable capsule, characterized in that consisting of reacting with isocyanate in the presence of a blowing agent and a reaction catalyst. Capsule containing carbon dioxide inside and consisting of calcium alginate gel; And Polyurethane biodegradable capsule, characterized in that it comprises a; coating layer made of a foamed polyurethane resin formed on the surface of the capsule. a) mixing a mixture of sodium alginate and sodium bicarbonate in an aqueous solution of calcium chloride with stirring to form a capsule of calcium alginate gel containing carbon dioxide therein: b) separating the capsule; And c) forming a coating layer made of a expandable polyurethane resin on the surface of the separated capsule; a method for producing a polyurethane biodegradable capsule, characterized in that it comprises a. Powder made of biodegradable material; Calcium alginate gel coating layer formed on the surface of the powder; And Polyurethane biodegradable capsules formed on the surface of the first coating layer, comprising an outer layer made of a expandable polyurethane resin produced by the addition polymerization of the active hydroxyl group and isocyanate of the calcium alginate gel. Capsule containing carbon dioxide inside and consisting of calcium alginate gel; And Polyurethane biodegradable capsule formed on the surface of the capsule, comprising an outer layer made of a foamed polyurethane resin produced by the addition polymerization of the active hydroxyl group and isocyanate of the calcium alginate gel.