KR20090008110A - Naturally degradable sheet using starch and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a naturally-degradable sheet mainly composed of non-modified starch, commercially available in the market, 5-80% by weight starch, 5-20% by weight of plasticizer starch, 5-50% by weight biodegradable material, auxiliary It is characterized by including the additive 3-55% by weight. Existing biodegradable sheet provides a more competitive natural degradable sheet by compensating for shortcomings of lack of industrial availability due to poor heat resistance, productivity, product formability, and lack of price competitiveness. Naturally degradable packaging material produced using the sheet according to the present invention takes hundreds of years at the time of landfill after use, thereby contributing to the prevention of environmental pollution by replacing the non-degradable synthetic resin that is unfriendly to the environment.

Description

Naturally degradable sheet using starch and manufacturing method thereof {NATURE BIODEGRADABLE SHEET CONTAING STARCH AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a naturally degradable sheet, characterized in that it comprises 5-80% by weight of starch, 5-20% by weight of plasticizer starch, 5-50% by weight of biodegradable material, and 3-55% by weight of auxiliary additives. In the case of the existing biodegradable sheet composition, the heat resistance, productivity, product formability, water resistance is poor, and the price competitiveness is insufficient to provide a more competitive natural degradable sheet to compensate for the shortcomings of the industrial availability. Naturally degradable sheet according to the present invention can produce a food container, an industrial packaging material, a buffer packaging material according to a general production method such as vacuum molding, vacuum forming, pressure forming. Various packaging materials manufactured using the sheet according to the present invention may take hundreds of years to completely decompose when landfilled after use, thereby contributing to the prevention of environmental pollution by replacing the non-degradable synthetic resin that is unfriendly to the environment.

Plastics, one of mankind's largest inventions, are widely used in the industrial field because of its advantages of durability, processability, chemical resistance, relatively low cost, and light weight, which contributes greatly to the convenience of human life. However, since it is a hardly decomposable substance that takes hundreds of years to be fully decomposed as a dysfunction, it remains for hundreds of years after being discarded after use, which seriously affects environmental pollution such as soil, air, and water pollution.

       Recently, with the increase of income level and the spread of the atmosphere for convenience of living, the demand for disposable products including plastic, which is hygienic, convenient and cheap, is increasing. In particular, fast food stores, convenience stores, department stores, marts, packaging materials such as food, various disposable products, packaging containers, etc. are mostly made of a thermoplastic polymer plastic, and the use of disposable products is increasing rapidly. However, thermoplastic polymers for manufacturing conventional packaging materials and disposable products are not only causing a number of environmental problems because they exist semi-permanently in nature, but also have the disadvantage of increasing waste generation. In addition, environmental hormones such as styrene oligomers, dioxins, and suspected environmental hormones may be generated, which is causing fatal harm in the future. In particular, environmental hormones and atopy, which affect sperm movement or reduce sperm count, may affect not only modern people but also human future.

      Currently, waste plastics are disposed of through landfilling, incineration, and recycling.However, landfilling is difficult because landfilling is not enough due to the increasing amount of garbage. In addition, the ground is not stable due to the plastic waste, which is a thermoplastic polymer that takes hundreds of years to decompose even after landfill, and there are many problems in the use of landfills, and in case of incineration, dioxins, as described above, are generated along with scattering dust. Hazardous gases such as carbon monoxide are generated in large quantities, causing air pollution and serious harm to the human body. Recently, the recycling of plastic products has been actively discussed, such as the treatment of plastic waste and its utilization.However, the economic feasibility due to the difficulty of separating and collecting plastic waste and the excessive cost of removing impurities mixed after collection. There are many problems such as aspects.

       In order to solve these problems, natural biodegradable materials include chitin, chitosan, alginic acid, collagen, bacterial cellulose, polyamino acid, and the like. Also derived from microorganisms or chemically synthesized, polylactic acid (PLA), polyhydroxybutyrate valerate (PHBV), polycaprolactone (PCL), polybutylene succinate (PBS), polyhydroxybutyrate (PHB), polyhydrate Aliphatic polyesters (AP) such as oxyalkanoate (PHA) and the like have been developed and marketed. However, there is a disadvantage that the price is expensive, it is difficult to use commercially because there is a price resistance of the existing consumer. In addition, heat resistance, processability, productivity is poor, the situation is not actively applied in the actual industrial field. Biodegradable raw materials that have been developed so far have weaknesses that are easily damaged due to their weak physical properties. Also, due to the high cost of raw materials, the economic efficiency is lowered, and the cooling time is long after production. There is a disadvantage.

      According to Korean Patent Registration 10-0535718, a method of laminating a plurality of sheets by a press, and also used a large amount of fibrous material having low elongation and elongation. Therefore, the manufactured sheet has a disadvantage in that the productivity is lowered and the defective rate is increased when the product is produced in the actual production site by vacuum forming, vacuum, etc. In addition, according to Korean Patent Registration No. 10-0675200, the raw material pretreatment process has a complicated disadvantage.

It is to solve the problem that the industrial availability is remarkably deteriorated due to the disadvantages of low moldability, low heat resistance, low productivity, and high price of the finished product of the existing biodegradable sheet. It can reduce the cost of the product, give heat resistance through reforming the properties of starch, and greatly increase the compatibility of starch, biodegradable materials, inorganic and organic additives, etc. The purpose is to provide a degradable sheet. Another object of the present invention is to provide a method for producing a naturally degradable sheet using starch.

This object of the present invention is achieved by the method of the present invention comprising the following steps:

Adding a starch, an inorganic filler, a plasticizer, and a lubricant to a mixer and mixing the mixture at high speed to remove moisture;

Two steps of high-speed mixing after further adding an antioxidant, a biodegradable substance, and a compatibilizer to the material in the step where moisture is removed;

One or more kneading zones and one or more reverse screws are used for the material completed until the mixing process, and a container capable of discharging volatile substances that may be generated when processing raw materials such as starch. Three steps of manufacturing a raw material pellet using a twin extruder having one or more vent holes installed therein;

The object of the present invention was achieved through the four steps of preparing a sheet in a sheet molding machine by adding the raw material pellets and the additive pellets as necessary.

Naturally degradable sheet according to the present invention is excellent in productivity and processability, excellent in hygiene and safety, and excellent in formability, processability, and productivity when used as a raw material sheet for manufacturing food packaging materials, industrial packaging materials, agricultural horticultural packaging materials, and buffer packaging materials. Compared with the existing biodegradable sheet, the price is low, and thus the industrial availability is excellent, and it can be used in a wide range of fields such as vacuum forming, vacuum forming, and pressing forming. After use, it is completely decomposed and circulated to the natural ecosystem to increase the organic matter in the soil and does not pollute the environment.

This object of the present invention is achieved by the method of the present invention comprising the following steps:

Adding a starch, an inorganic filler, a plasticizer, and a lubricant to a mixer and mixing the mixture at high speed to remove moisture;

Two steps of high-speed mixing after further adding an antioxidant, a biodegradable substance, and a compatibilizer to the material in the step where moisture is removed;

One or more kneading zones and one or more reverse screws are used for the material completed until the mixing process, and a container capable of discharging volatile substances that may be generated when processing raw materials such as starch. Three steps of manufacturing a raw material pellet using a twin extruder having one or more vent holes installed therein;

Four steps of manufacturing a sheet in a sheet molding machine by adding the raw material pellets obtained above, and additive pellets if necessary

In the present invention, the amount of each raw material used may be 5-80% by weight of starch, 5-20% by weight of plasticizer starch, 5-50% by weight of biodegradable material, and 3-55% by weight of auxiliary additives.

The starch is a starch which has not undergone the modification process commonly used in the art, for example, starch extracted from various plants such as corn, potato, tapioca, sweet potato, wheat, rice and grains. Starch is divided into ground starch and underground starch according to the type of plant and storage area. Each starch has different shape, particle size, and unique characteristics of starch particle shape, particle size, and appearance, and there are many differences in physicochemical properties according to varieties. In many cases, one or more mixtures selected from the group consisting of corn starch, tapioca starch and wheat starch were used as raw starch in the present invention. The amount used may be 3.0 to 90% by weight, preferably 5 to 80% by weight based on the total weight of the composition. When starch is used in an amount of 80% by weight or more, there is a problem in that moldability, physical properties, processability and water resistance are lowered.

The plasticizer is used for the purpose of changing the physical properties of the polymer organic material such as starch. When the plasticizer is added and processed into the polymer material, the blend increases flexibility, elasticity, and warpage, thereby improving workability and formability. Polymeric material such as starch itself is not easily deformed due to its large molecular weight, but plasticity can be easily deformed by external force. In the present invention, the plasticizer may be one or more mixtures selected from the group consisting of glycerin, glycerol monostearate (GMS), sorbitol, oleic acid, linoleic acid, stearic acid, palmitic acid, lauric acid, malic acid, ethylene glycol, and the like. The amount of the starch may be 3.0 to 30% by weight, preferably 5.0 to 25% by weight, based on the amount of starch used. Plasticizers have the effect of improving the fluidity and processability of starch. Starch may not be denatured when used at 3.0 wt% or less, and may dissolve to the surface when used at 30% or more, and also deteriorate the quality of the sheet and increase the cost. There is this.

The biodegradable material is PLA (Polylactic acid), PHBV (Poly-3-hydroxy phenyl valerate), PCL (Polycaprolactone), PBS (Polybutylene succinate), PHB (Poly-hydrxy butyrate), PHA (Poly-hydroxy alkanoate), PGA ( Polyglycolic acid), cellulose powder, soybean meal powder, coffee foil powder, etc. may be used one or more selected from the group consisting of 3 to 60% by weight, preferably 5 to 60% by weight based on the total weight of the composition 50 weight percent. Aliphatic polyester may affect sheet formation and sheet strength deterioration when the sheet is formed when used in an amount of 5 wt% or less, and material costs may increase when used in an amount of 50 wt% or more.

In the auxiliary additive, the inorganic filler may be used alone or in combination with calcium carbonate, talc, kaolin, pearlite, zeolite, clay, and the amount thereof is 0.3 to 50% by weight, preferably 1 based on the total weight of the composition. To 45% by weight. Since the inorganic filler is basically inexpensive, cost reduction of the composition is possible. In addition, in terms of product properties, it can be expected to prevent shrinkage, that is, supplementation of physical properties such as improvement of dimensional stability and flexural modulus.

Among the auxiliary additives, antioxidants include dilaurylthiodipropionate (DLTDP), a phenolic 2,6-dishatributyl-P-cresol (3,5-di-tertbutyl-4-hydroxytoluene, dibutyl Hydroxytoluene propanoic acid may be used alone or in combination, the amount of which may be 0.01 to 0.5% by weight, preferably 0.02 to 0.2% by weight.

Among the auxiliary additives, the lubricant may be used alone or in combination with piwax (PEW), pipiwax (PPW), calcium stearate, zinc stearate, glycerin stearate, butyl stearate, wax, paraffin, mineral oil, The amount used may be 0.1 to 10% by weight, preferably 0.5 to 8% by weight. Lubricants have a disadvantage in that the cost of materials is increased when using behenic acid series having 22 lubricating effect, which is excellent in lubricating effect. In terms of economics, there is an advantage in using the same kind. In addition, when using a fatty acid-based lubricant, there is an advantage that shows affinity to inorganic materials, such as filler. Lubricants are additives that are used to literally reduce and smooth the friction between raw materials. Not all frictions are bad, but the heat of friction during material mixing, melting, and processing causes the raw materials to decompose by heating more than necessary, carbonizing organic additives such as starch in the raw materials, and It is used to eliminate the occurrence of defects by pressing on the surface.

Among the auxiliary additives, the compatibilizer may be used alone or in combination of benzoyl peroxide, polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), benzophenone, glycerin mono fatty acid ester, and citric acid. The amount thereof may be 0.001 to 1% by weight, preferably 0.005 to 2% by weight. The compatibilizer is present at the interface between the raw materials due to the interfacial action between the raw materials used, thereby lowering the interfacial tension, and improving the compatibility between raw materials by improving the reactivity between the raw materials. Improve the defective rate, lowering the physical properties.

The naturally degradable sheet described in the present invention can be used for vacuum forming, vacuum forming, pressure forming, and the like, and can be used as a raw material for manufacturing food packaging materials, industrial packaging materials, buffer packaging materials and the like.

Hereinafter, the present invention may be described in detail.

However, the present invention is not limited by the following examples.

<Example 1>

Friction heat generated by adding 55% by weight of corn starch, 4.0% by weight of glycerin, 5.0% by weight of sorbitol, 9.8% by weight of calcium carbonate, 3.0% by weight of talc, 0.5% by weight of PEW, and 2.5% by weight of zinc stearate. Mix with water to remove moisture from raw materials. Then 20.0% by weight of PLA, 0.18% by weight of DLTDP and 0.02% by weight of benzoyl peroxide were added to the mixer, followed by thermal mixing at high speed for further water removal and mixing. Pellets were prepared using a twin extruder having at least one vent hole for discharging volatiles from the raw material obtained by mixing at room temperature.

<Example 2>

Corn Starch 55%, Glycerine 4.0%, Sorbitol 5.0%, Calcium Carbonate 9.8%, Talc 3.0%, PEW 0.5%, Zinc Stearate 2.5%, PLA 20.0%, DLTDP 0.18%, Benzoyl Peroxide 0.02% by weight was added to the pressurized kneader and then made into a dough state, and pellets were prepared by supplying a dough-like raw material to the extruder.

<Example 3>

The pellets prepared in Example 1 or Example 2 were molded using a general sheet molding machine.

Claims (10)

Naturally degradable sheet comprising 5-80% by weight of starch, 5-20% by weight of plasticizer starch, 5-50% by weight of biodegradable substance, and 3-55% by weight of auxiliary additive. The method of claim 1, wherein the starch is one or two or more selected from corn starch, potato starch, tapioca starch, sweet potato starch, wheat starch, rice starch. The method according to claim 1, wherein the plasticizer is one or two or more selected from glycerin, glycerol monostearate, sorbitol, oleic acid, linoleic acid, stearic acid, palmitic acid, lauric acid, malic acid and ethylene glycol. Sheet The biodegradable sheet according to claim 1, wherein the biodegradable material is one or two or more selected from PLA, PHBV, PCL, PBS, PHB, PHA, and PGA. 2. The naturally degradable sheet according to claim 1, wherein the auxiliary additive is one or two or more selected from inorganic fillers, antioxidants, lubricants, and compatibilizers. The decomposable sheet according to claim 5, wherein the inorganic filler is one or two or more selected from calcium carbonate, talc, kaolin, pearlite, zeolite and clay. The antioxidant according to claim 5, wherein the antioxidant is dilaurylthiodipropionate (DLTDP), dibutylhydroxytoluenepropanoic acid, and phenolic 2,6-dishatributyl-P-cresol (3,5-di-third) Naturally degradable sheet characterized in that one or two or more selected from butyl-4-hydroxytoluene The lubricant according to claim 5, wherein the lubricant is one or two or more selected from PEW, PEW, PPW, calcium stearate, zinc stearate, glycerin stearate, butyl stearate, wax, paraffin, and mineral oil. Naturally degradable sheet characterized in that The method of claim 5, wherein the compatibilizer is one or more selected from benzoyl peroxide, polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA), benzophenone, glycolic mono fatty acid ester, citric acid Degradable sheet         Adding a starch, an inorganic filler, a plasticizer, and a lubricant to a mixer and mixing the mixture at high speed to remove moisture; Two steps of high-speed mixing after further adding an antioxidant, a biodegradable substance, and a compatibilizer to the material in the step where moisture is removed; One or more kneading zones and one or more reverse screws are used for the material completed until the mixing process, and a container capable of discharging volatile substances that may be generated when processing raw materials such as starch. Three steps of manufacturing a raw material pellet using a twin extruder having one or more vent holes installed therein; Method for producing a naturally degradable sheet comprising the step of preparing a sheet in a sheet molding machine by adding the raw material pellets, additive pellets, if necessary