KR20200055174A - Complex decomposable sheet or vacuum formed product capable of maintaining freshness - Google Patents

Abstract

The present invention provides a multi-degradable additive composition with a freshness-retaining function, which comprises: 10 to 15 parts by weight of coconut shell; 5 to 10 parts by weight of a waste paper particulate material; 0.05 to 0.5 parts by weight of wax; 1.0 to 2.0 parts by weight of a plasticizer; 0.5 to 2.0 parts by weight of an oxidation initiator; 1.0 to 5.0 parts by weight of metal ion salt; 0.01 to 1.0 parts by weight of peroxide; 0.5 to 2.0 parts by weight of organic acid; 0.5 to 2.0 parts by weight of a thermal decomposition initiator; 5.0 to 10.0 parts by weight of glue; 1.0 to 5.0 parts by weight of a freshness-retaining agent; and a residual amount of a binder resin having a molecular weight of 3,000 to 5,000 Da, with regard to 100 parts by weight of the entire multi-degradable additive composition. According another exemplary embodiment of the present invention, provided is the multi-degradable additive composition with the freshness-retaining function, wherein the freshness-retaining agent comprises: 65 to 75 wt% of a porous material; 15 to 25 wt% of a functional mineral substance; and 10 to 15 wt% of a natural antimicrobial agent. According to the present invention, it is possible to manufacture a sheet or a food container with the freshness-retaining function by extruding or vacuum-forming the multi-degradable additive composition with the freshness-retaining function, a polymer resin, and a decomposition co-promoter.

Description

Complex decomposable sheet or vacuum formed product capable of maintaining freshness}

The present invention relates to a sheet or vacuum molded article having a freshness retention function prepared using a composite decomposition additive composition having a freshness retention function containing a biomass such as coconut skin, waste paper powder and a freshness retention additive, and is porous as a freshness retention additive It relates to a sheet or vacuum molded article manufactured using a composite decomposition additive composition having excellent biodegradability and freshness retention function by including a substance, a functional mineral and a natural antibacterial agent.

In the UAE, Pakistan, France, Italy, New York, and the United States, legislation to distribute products using degradable plastics in packaging materials or products is being passed or is in progress. As of January 1, 2014, the UAE replaced all packaging materials in the UAE region with oxidative biodegradable plastics, a type of degradable plastics, and fines of approximately 850 million won for violations. UAE's oxidative biodegradable plastic is UAE S 5009 based on ASTM D 6954, and has a final decomposition period of 36 months. In New York, the United States enacted a bill on January 1, 2015 to encourage the use of degradable plastics, with a six-month grace period. In New York State, the decomposition period of degradable plastics is set to within 2 years, and it is recommended to use degradable plastics that are 12 months shorter than the UAE.

In general, degradable plastics can be divided into biodegradation, oxidative biodegradation, photolysis or photodecay depending on the decomposition period. Of these, biodegradable plastics should decompose more than 90% of the standard cellulose, within 6 months under industrial composting conditions, and oxidative biodegradable plastics should decompose more than 90% within 36 months. In the case of photo-degradable and photo-degradable plastics, the product disappears, but it is also excluded from the category of degradable plastics because it takes about 50 years or more to completely decompose into water and carbon dioxide. Therefore, biodegradable plastics or oxidized biodegradable plastics must be used to meet the standards or product sales standards of foreign countries.

In the case of biodegradable plastics, biodegradable plastics are more expensive than general plastics, have a limited use range, and have relatively low biodegradable plastics. In the case of oxidative biodegradable plastics, it is produced by adding a small amount of oxidative biodegradable additives to ordinary polymers, so it has the advantage of being inexpensive and having no difference in physical properties from ordinary polymers. In addition, oxidative biodegradable plastics have the advantage of controlling the decomposition period according to the ratio of the additives to be added, the degree of concentration and the amount of the antioxidant.

However, in order to biodegrade the existing oxidative biodegradable plastic within two years, the amount of the additive to be added must increase, and when the amount of the additive is increased, physical properties may decrease or transparency may decrease and the unit price of the product may increase.

Therefore, it is intended to be applied to packaging materials and storage containers of various products by manufacturing sheet or vacuum molded products using this by manufacturing additive pellets having a complex degradability and freshness retention function, which can be used in fields that do not require high levels of strength and elongation. do.

Prior Art 1: Patent Registration No. 10-1732987 (volume based, published on May 8, 2017) Eco-friendly polymer plastic manufacturing method containing phytoncide

The present invention is a composite decomposition additive composition containing a coconut skin, waste paper powder biomass that can harmoniously implement carbon properties, excellent biodegradability and mechanical properties such as tensile strength and elongation, and a freshness retention agent, composite decomposition additive pellets And it is intended to manufacture a sheet or vacuum molded product having a function of maintaining freshness through extrusion or vacuum molding using a polymer resin.

In order to solve the above technical problem, the present invention, with respect to 100 parts by weight of the total composite decomposition additive composition, coconut skin 10 to 15 parts by weight; 5 to 10 parts by weight of waste paper powder; 0.05 to 0.5 parts by weight of wax; Plasticizer 1.0 to 2.0 parts by weight; 0.5 to 2.0 parts by weight of an oxidation initiator; Metal ion salt 1.0 to 5.0 parts by weight; Peroxide 0.01 to 1.0 parts by weight; 0.5 to 2.0 parts by weight of organic acid; Pyrolysis initiator 0.5 to 2.0 parts by weight; Freshness retention agent 1.0 to 5.0 parts by weight; Provides a composite decomposition additive composition having a freshness retention function, characterized in that it comprises a binder resin having a molecular weight of 3,000 to 5,000 Da with 5.0 to 10.0 parts by weight of glue and remaining amount.

According to another suitable embodiment of the invention, the freshness-retaining agent is from 65 to 75 wt% of the porous material; It provides a composite decomposition additive composition having a freshness retention function, characterized in that consisting of 15 to 25wt% of functional minerals and 10 to 15wt% of natural antibacterial agents.

According to another suitable embodiment of the present invention, the freshness-retaining agent provides a composite decomposition additive composition having a freshness-keeping function, wherein the natural antibacterial agent is impregnated in the porous material.

According to another suitable embodiment of the present invention, a composite decomposition additive pellet having a function of maintaining freshness is prepared from the composite decomposition additive composition.

According to another suitable embodiment of the present invention, the composite decomposition additive pellets; Polymer resins; Decomposition auxiliary accelerators are mixed to provide a sheet or vacuum formed product having a function of maintaining freshness extruded or vacuum-formed.

By including coconut skin and waste paper powder in the additive composition according to the present invention, it has a carbon-reducing effect and can reduce the environmental burden by promoting the decomposition of the resin, and has the advantage of being able to cope with international environmental regulations.

The freshness retention agent included in the additive composition according to the present invention can be applied to a sheet or a vacuum formed article used as a packaging paper or a food container to extend a storage organ of food.

The composition for vacuum molding prepared from the composite decomposition additive pellets having a function of maintaining freshness according to the present invention is environmentally friendly because it decomposes after a certain period of time even when discarded after use.

1 is a photograph comparing the freshness-preserving performance of eggs in the food storage container and the existing food storage container containing the freshness-retaining agent according to the present invention.

The composite decomposition additive composition having a function of maintaining freshness according to the present invention, based on 100 parts by weight of the composite decomposition additive composition, 10 to 15 parts by weight of coconut skin; 5 to 10 parts by weight of waste paper powder; 0.05 to 0.5 parts by weight of wax; Plasticizer 1.0 to 2.0 parts by weight; 0.5 to 2.0 parts by weight of an oxidation initiator; Metal ion salt 1.0 to 5.0 parts by weight; Peroxide 0.01 to 1.0 parts by weight; 0.5 to 2.0 parts by weight of organic acid; Pyrolysis initiator 0.5 to 2.0 parts by weight; Freshness retention agent 1.0 to 5.0 parts by weight; It comprises 5.0 to 10.0 parts by weight of glue and a binder resin having a molecular weight of 3,000 to 5,000 Da in the remainder.

Coconut blood is used as a raw material for biomass. Coconut blood in the present invention may mean a mixture of an inner shell that directly surrounds flesh in a coconut fruit and an outer shell that covers the inner shell (husk), and a trace amount of inevitably incorporated in the process of collecting coconut blood. It may mean that by-products are included. The outer shell of coconut skin occupies a high specific gravity of 33% based on the total weight of the fruit, and in particular, the inner shell is composed of lignin and fibrin, which are wood-based polymers such as hard wood, with high density and uniform density, thereby being prepared from the additive composition according to the present invention. It has favorable conditions to impart physical properties such as rigidity to the product. In addition, palm oil contained in the coconut skin serves to protect the screw during pellet production, and the double bond possessed by the coconut skin has favorable conditions for improving biodegradability by facilitating radical reaction through redox. On the other hand, in the biomass, it is advantageous to use a biomass having a low water content, since the water content may cause carbonization in the processing process or weaken the binding force in the process of blending with other raw materials. Thus, coconut skin has a water content of about 8% lower than that of biomass such as sugar cane, wood, coffee husk and rice straw having a water content of 10 to 60%, and thus can be advantageously used as a raw material for biomass according to the present invention. have. However, such coconut skin may have an increased water content due to external factors such as a storage environment, and an additional drying process may be performed to control the desired water content. The drying process may be performed in a drying method such as, for example, hot air drying for 3 to 5 hours in a device equipped with a temperature condition of 80 to 100 ° C, and the devices used in the drying process include a tumble dryer and a conveyor belt. An installed closed chamber or compounding device may be used, but is not limited thereto, and various drying devices known in the art may be used. The drying process may be performed only once, but may be performed several times as necessary, and the coconut skin may have a water content of 10% or less by such a drying process. Coconut skin dried at a water content of 10% or less can be pulverized to a size of 100 to 400 mesh by any grinder known in the art so that it can be mixed homogeneously with other raw materials, and in the present invention to a size of 100 to 400 mesh The crushed coconut blood is called a coconut blood powder. Coconut skin powder, for the biodegradability of various products including pellets prepared from the additive composition according to the present invention, 10 parts by weight or more may be used with respect to 100 parts by weight of the total additive composition, and when used in excess of 15 parts by weight Since it may cause a decrease, preferably 10 to 15 parts by weight may be used.

Waste paper powder refers to pulverized waste paper into fine powder, and waste paper is a general paper, meaning oil-derived resources such as newspapers. It is preferable to adjust the size of the fine powder according to the plastic product to be produced, and for example, the fine powder may be formed in a size of 100 to 400 mesh. The present invention can improve the degradability by pulverizing waste paper rather than using synthetic resin as in conventional plastic products. On the other hand, plastic products recently developed using biomass have the advantage of improved degradability compared to plastic products made of conventional synthetic resins, but lignin-induced carbonization during the manufacturing process causes odor problems. There is a disadvantage that the product's productability is poor. However, the present invention also has the effect of minimizing this odor problem by replacing the biomass with waste paper powder. The waste paper powder is preferably included in 5 to 10 parts by weight based on 100 parts by weight of the polymer resin. When the content of the waste paper powder is less than 5 parts by weight, there is a disadvantage that the degradability of the manufactured plastic product may be deteriorated due to insufficient content compared to the polymer resin. There is a disadvantage that physical properties may be weakened.

The wax may be used in a manner of coating the surface of the coconut skin to prevent re-absorption of the dried coconut skin powder, preferably paraffin wax, liquid paraffin wax, beeswax, drive wax, emulsifying wax, candelilla Wax, polyethylene wax and polypropylene wax can be used. In addition, the wax can be used advantageously in the present invention by having the advantage of being capable of acting as an auxiliary agent for the lubricant, and of being easily biodegradable due to a low molecular structure. For the wax function as a coating function and a lubricant auxiliary agent, 0.05 parts by weight or more may be used with respect to 100 parts by weight of the total additive composition, and when used in excess of 0.5 parts by weight, residues may be generated in the dies, and therefore preferably 0.05 to 0.5 parts by weight may be used.

A plasticizer may be used for plasticizing the coconut skin powder coated with wax, and a sodium-based plasticizer may be used to mask the dark color caused by lignin while increasing degradability by substituting lignin of the coconut blood. Sodium-based plasticizers are sodium hydrogensulfite (NaHSO ₃ ), sodium percarbonate (2Na ₂ CO ₃ , 3H ₂ O ₂ ), sodium bicarbonate (NaHCO ₃ ), sodium chloride (NaCl) , Meta-sodium silicate (Na ₂ SiO ₃ ), sodium borate decahydrate (Na ₂ B ₄ O ₇ · 10H ₂ O) and one or more selected from the group consisting of soda ash (soda ash, Na ₂ CO ₃ ) Can be, preferably sodium metasilicate (Na ₂ SiO ₃ ), sodium borate decahydrate (Na ₂ B ₄ O ₇ · 10H ₂ O) or mixtures thereof (eg, 3: 7 to 7: A weight ratio of 3, more specifically, mixed in a weight ratio of 5: 5) may be used. Sodium-based plasticizer may be used in an amount of 1.0 part by weight or more based on 100 parts by weight of the total additive composition for plasticizing the wax-coated coconut skin powder and oxidizing effect of the polymer. It is preferable that 1.0 to 2.0 parts by weight is used because blood may be carbonized or physical properties may be deteriorated.

Oxidation initiators can be used to accelerate the decomposition reaction of the resin, preferably natural polyunsaturated fatty acids having an active methylene group can be used. The active methylene group formed on the polyunsaturated fatty acid can be automatically oxidized by catalysis such as light and heat, and then promote the oxidative decomposition of the resin by causing the lipid to deteriorate. Such an organic oxidation initiator may be advantageous to have a low molecular structure in order to improve degradability, and preferably C18-based alpha-linolenic acid (ALA), gamma-linolenic acid (GLA), and mixtures thereof (For example, a weight ratio of 4: 6 to 6: 4, more specifically, a weight ratio of 5: 5) may be used. When used in an amount of less than 0.5 part by weight based on 100 parts by weight of the total additive composition, the organic oxidizing initiator becomes inferior in decomposition effect, and when used in excess of 2 parts by weight, may cause unnecessary increase in manufacturing cost and rapid oxidation. It can be used, preferably 0.5 to 2 parts by weight.

The metal ion salt can be used to initiate a radical reaction with energy generated by repeated redox reaction with peroxide, which will be described later. By this reaction, the polymer carbon chain is cut and oxidative decomposition occurs, so that the polymer can be reduced in molecular weight. The low-molecular-weight oxidized low-molecular weight product is finally digested and absorbed by microorganisms in the natural environment, and converted into water and carbon dioxide to complete decomposition. The metal ion salt according to the present invention is preferably Nickelous acetate, Nickel (II) acetate, Nickel (II) oxalate, Manganous acetate, Manganic acetate, Manganous oxalate, Cobaltous acetate, Cobaltic acetate Cobaltous oxalate, Ferric (III) formate and Ferric ( Ⅱ) It may be one or more selected from the group consisting of lactate. When the metal ion salt is used in an amount of less than 1 part by weight with respect to 100 parts by weight of the total additive composition, the oxidative decomposition effect of the resin becomes insufficient, and when it is used in excess of 5 parts by weight, it may cause an increase in manufacturing cost. It may be used in 5 parts by weight.

Peroxide may be used to activate the radical reaction of the energy generated by the redox reaction with the metal ion salt, and additionally can be used to form the graft bond of the plasticized coconut skin powder and the binder polymer to be described later. . Peroxides include t-butyl (2-ethylhexyl) monoperoxycarbonate, t-butyl isopropyl monoperoxycarbonate, t-amyl (2-ethylhexyl) monoperoxycarbonate, 1,1-di (t-butylfe) Roxy) cyclohexane, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and 1,1-di (t-amylperoxy) cyclohexane. It can be strange. Peroxide may be used in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the total additive composition, and when used in an amount of less than 0.01 part by weight, it is difficult to expect a graft bonding effect with the polymer due to less generation of resin polymer end groups, or natural decomposition of the resin And the oxidation effect is reduced may cause a problem that the final period of natural decomposition is prolonged, and when used in excess of 1 part by weight, it may decompose too early, and thus preferably 0.01 to 1 part by weight.

The organic acid can be used to induce crosslinking between the plasticized coconut skin powder and the binder polymer, and to react with metal ions to promote the decomposition of the polymer, and the organic acid according to the present invention is preferably propionic acid, paranitbenzoic acid, It may be one or more selected from the group consisting of citric acid, malic acid and maleic acid. When used in an amount of less than 0.5 parts by weight based on 100 parts by weight of the total additive composition, the organic acid may have poor oxidative decomposition function, and when used in excess of 2 parts by weight, may cause an unnecessary increase in manufacturing cost, and preferably 0.5 to 2 It can be used in parts by weight.

As the pyrolysis initiator, an azo compound may be preferably used. The azo compound undergoes radical initiation reaction by forming two radicals by simultaneously decomposing both bonds of the azo group (-N = N-) by heating. Pyrolysis initiators are azobenzene, methyl red, 2,2'-azobisisobutyronitrile, bismarck brown, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2- Amidinopropane) dihydrochloride, 1,1'-azobis (cyclohexanecarbonitrile), 1,1'-azobis (N, N-dimethylformamide) and 2,2'-azobis (4- One or more selected from the group consisting of methoxy-2,4-dimethylvaleronitrile) may be used, preferably 1 to 2 parts by weight based on 100 parts by weight of the total additive composition.

Glue is a material that solidifies the liquid by orphaning animal skins, intestines, and bones, and serves as a binder that combines polymer resin and waste paper powder. Conventionally, synthetic resins such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and high-density polyethylene (HDPE) have been used as binders, but the mixed composition sticks well, but because of the synthetic resin, the degradability of the final product, the plastic product Lowered. On the other hand, in the case of glue, it is possible to enhance the eco-friendly properties by improving the degradability of the final product, the plastic product, while keeping it well entangled between the polymer resin and the waste paper powder. Glue is preferably included in 5 to 10 parts by weight based on 100 parts by weight of the total composite decomposition additive composition. When the content of glue is less than 5 parts by weight, there is a disadvantage that the shape of the plastic product manufactured is not well formed because the polymer resin and the waste paper powder are not properly entangled, and when it exceeds 10 parts by weight, the content of the polymer resin is relatively There is a disadvantage that the mechanical properties of the final finished plastic product is reduced.

The freshness retention agent is composed of 65 to 75 wt% of a porous material, 15 to 25 wt% of a functional mineral material, and 10 to 15 wt% of a natural antibacterial agent, and it is preferable that the natural antibacterial agent is supported on the porous material.

The porous material is a carrier of a functional material having an antibacterial or freshness retention function in the present invention. It is preferred that at least one selected from the group consisting of mullite, amorphous aluminosilicate, zeolite, and mesoporous silica is used as the porous material.

The functional mineral is preferably one or more selected from the group consisting of Xenotime, Gadolinite, and Euxenite. Functional minerals emit beneficial vibration waves (6 ~ 12㎛), which can kill microorganisms, fungi and viruses, and destroy the cell walls of microorganisms, fungi and viruses to facilitate the action of natural antibacterial agents Together with natural antibacterial agents, synergism is performed to improve the function of maintaining freshness.

The natural antibacterial agent is preferably one or more selected from the group consisting of acid shool, propolis, and chitosan. The natural antibacterial agent may exert a synergistic antibacterial action when trapped in a porous material.

The method of supporting the natural antibacterial agent on the porous material may be a wet method, but is not limited thereto. That is, by mixing and mixing the porous particles and the natural antibacterial agent, the antimicrobial material is penetrated. However, in this way, the amount of the natural antibacterial agent supported on the porous material is only 10% by weight, so there is a limit in exerting sufficient freshness maintaining function. As a method for supporting the natural antibacterial agent carried on the porous material, the amount of the natural antibacterial agent carried on the porous material can be increased to 15 to 20% by weight by performing ultrasonic treatment in parallel, whereby the food packaging material is sufficient It becomes possible to exert a function of maintaining freshness.

Binder resins are polyethylene (PE), linear low polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), ethylene vinyl acetate (EVA), polyvinyl alcohol (PVA), polypropylene (PP), polylactic acid ( PLA) and polyhydroxybutyrate (PHB), and may be one or more selected from the group consisting of, and the binder resin may be used in the residual amount range of the above components with respect to 100 parts by weight of the total additive composition.

Meanwhile, the molecular weight of the binder resin is 3,000 to 5,000 Da. Existing biodegradable resins were prepared to exhibit biodegradability by adding a significant amount of biodegradable resin when preparing a vacuum molded composition, instead of using a polymer having a molecular weight of 10,000 Da or more as a binder resin. The composite decomposition additive composition having a function of maintaining freshness according to the present invention uses a binder resin having a molecular weight of 3,000 to 5,000 Da in the range of food packaging while exhibiting sufficient biodegradability even without adding a biodegradable resin separately in the process for manufacturing a composition for vacuum molding. Or it has a feature in producing a sheet or a vacuum forming composition having a function of maintaining freshness that exhibits mechanical properties that can be sufficiently used as a food container.

When the molecular weight of the binder resin is less than 3,000 Da, it is difficult to have sufficient mechanical properties when prepared as a food packaging material or storage container, and when the molecular weight exceeds 5,000 Da, the biodegradability is lowered in the process of being discarded after use.

In addition, additives for the production of plastics known in this field may be used to improve processability, product stability, product performance, and the like, and a compatibilizer, a lubricant, and inorganic substances may be additionally added.

The composite decomposition additive composition having a function of maintaining freshness may be prepared as a composite decomposition additive pellet by a pelletization method known in the art.

In order to produce a composite decomposition additive pellet, the composite decomposition additive composition having a function of maintaining freshness is melt-kneaded by a melt-kneading apparatus known in the art, such as a kneader or horizontal stirrer including a semi-barrier mixer, a single-screw extruder, or a twin-screw compressor. It can be used, plasticizing of coconut skin, waste paper powder and plasticized coconut skin, a twin screw extruder can be preferably used for graft bonding of waste paper powder and binder polymer. When the reaction temperature of the extruder is less than 100 ° C, it may be difficult to mix the added raw materials due to insufficient melting, and when it exceeds 300 ° C, carbonization may occur or the viscosity of the resin due to high temperature may be excessively low. Since molding may not be possible in the form of pellets, the reaction temperature of the extruder can be preferably maintained in a temperature range of 100 to 300 ° C. In addition, the rotational speed of the screw may be 300 rpm or more for preventing productivity deterioration and ease of mixing between raw materials, and when it exceeds 800 rpm, carbonization of coconut blood due to an increase in temperature as the internal pressure of the screw increases Since it can be generated, the rotational speed of the screw may preferably have a rotational speed range of 300 to 800 rpm. The composite decomposition additive composition melt-kneaded by the above method may be prepared as a composite decomposition additive pellet having a function of maintaining freshness by being cooled through an extruder and then cut to a certain size.

The composition for molding according to the present invention may be prepared by mixing the pellets of a composite decomposition additive having a function of maintaining freshness, a polymer resin, and a decomposition aid promoter.

The composite decomposition additive pellets having a function of maintaining freshness may be added in an amount of 1 to 20 parts by weight based on 100 parts by weight of the total molding composition. When the composite decomposition additive pellet is used in an amount of less than 1 part by weight, the carbon reduction effect and biodegradability effect according to the biomass added to the composition for molding becomes insufficient, and when used in excess of 20 parts by weight, tensile of the sheet produced from the composition for molding Since problems such as deterioration in physical properties such as strength follow, preferably 1 to 20 parts by weight may be used, and more preferably 1 to 5 parts by weight may be used.

The polymer resin can be a thermoplastic resin known in the art, polystyrene (PS), polypropylene (PP), polylactic acid (PLA), polyethylene terephthalate (PET), polyethylene (PE), linear low-polyethylene (LLDPE) , Low density polyethylene (LDPE), high density polyethylene (HDPE), ethylene vinyl acetate (EVA), polyvinyl alcohol (PVA) and polyhydroxybutyrate (PHB). For the polymer resin according to the present invention, the same resin as the binder resin used in the composite decomposition additive pellet may be used to improve the bonding strength between the raw materials, and preferably a mixture of high density polyethylene (HDPE) and polypropylene (PP) (for example, 1: 1 to 1:10 in a weight ratio) may be used. The polymer resin may be used in an amount of 45 to 90 parts by weight based on 100 parts by weight of the entire molding composition for improving physical properties of the biodegradable sheet prepared from the molding composition. In addition, the polymer resin uses a known polymer resin having a molecular weight of 3,000 to 5,000 Da in order to improve biodegradability.

An inorganic material may be used as a decomposition auxiliary accelerator, and such an inorganic material may contribute to improving durability of the biodegradable sheet according to the present invention. As a decomposition aid accelerator according to the present invention, preferably a mixture of calcium carbonate and talc (eg, mixed in a weight ratio of 1: 6 to 6: 1) can be used. When the decomposition auxiliary accelerator is used in an amount of less than 5 parts by weight relative to 100 parts by weight of the total molding composition, the durability of the biodegradable sheet may be reduced, and when used in excess of 40 parts by weight, the blending ratio of other raw materials added is reduced. 5 to 40 parts by weight can be used.

The molding composition may be manufactured in a sheet form by a molding method known in the art, and may be applied to the field of disposable products such as packaging materials, food packaging containers, cups, tableware, and disposables by vacuum molding.

[Example]

(1) Preparation of freshness preservative

20 parts by weight of a mixture of Xenotime: Gadolinite mixed in a ratio of 5: 5 as a functional mineral; Porous mineral 65 parts by weight of zeolite; And it was prepared by mixing 15 parts by weight of a mixture of chitosan: propolis mixed in a 5: 5 weight ratio as a natural antibacterial agent. First, while mixing 65 parts by weight of a zeolite porous material and 15 parts by weight of a mixture of chitosan: propolis in a stirrer, ultrasonic waves at 10 kHz were irradiated for 10 minutes. The natural antibacterial agent prepared in this way has a natural antibacterial agent loading rate of zeolite of 15 to 18 wt%, and when untreated, it carries 5 to 8 wt% or more of the natural antibacterial agent higher than the loading rate of 10 wt%. The freshness-preserving agent is prepared by mixing a functional mineral with a zeolite carrying a natural antibacterial agent prepared in this way.

(2) Preparation of a composite decomposition additive composition having a function of maintaining freshness

100 parts by weight of the total complex decomposition additive composition, 15 parts by weight of coconut skin; Waste paper powder 10 parts by weight; 0.25 parts by weight of polyethylene wax; 1.2 parts by weight of a mixture of sodium metasilicate and sodium borate 10 hydrate mixed in a weight ratio of 5: 5; 1 part by weight of a mixture of alphalinolenic acid and gammalinolenic acid mixed in a weight ratio of 5: 5; 2.5: 5 parts by weight of ferric (III) formate and ferric (II) lactate mixed in a weight ratio of 5: 5; 0.05 parts by weight of 1,3-bis (thi-butylperoxy-isopropyl) benzene; 1 part by weight of t-butyl isopropyl monoperoxycarbonate; 1.5 parts by weight of 2,2'-azobisisobutyronitrile; 10 parts by weight of glue; 34.5 parts by weight of the freshness retention agent and 54.5 parts by weight of polyethylene with a molecular weight of 5,000 Da were added to the super mixer, followed by mixing at a temperature of 130 to 160 ° C for 12 minutes to prepare a composite decomposition additive composition.

(3) Preparation of complex decomposition additive pellets

After melt-kneading the prepared composite decomposition additive composition using a twin-screw extruder, the reaction temperature is 100 to 300 ° C, the screw is rotated through a twin-screw extruder having a speed of 300 to 800 RPM, cooled, and then cut to a certain size. Composite decomposition additive pellets were prepared.

(4) Preparation of molding composition and biodegradable sheet

5 parts by weight of the composite decomposition additive pellets prepared above, based on 100 parts by weight of the total molding composition; 75 parts by weight of polyethylene (PE) having a molecular weight of 5,000 Da; 20 parts by weight of calcium carbonate; After mixing 10 parts by weight of talc to prepare a molding composition, a biodegradable sheet was prepared using a sheet manufacturing facility known in the art. In addition, a vacuum storage molding was performed using this sheet to prepare a food storage container.

[Comparative example]

Comparative Example 1

A composition for molding and a biodegradable sheet according to the composite decomposition additive composition were prepared in the same manner as in Example 1, except that 45 parts by weight of 15,000 Da polyethylene and 30 parts by weight of polylactic acid (PLA) were used.

Using this sheet, a food storage container was prepared by a vacuum forming method.

Comparative Example 2

In Example 1, without using 3 parts by weight of the freshness-retaining agent, a biodegradable sheet according to the composite decomposition additive composition was prepared in the same manner as in Example 1, except that a binder resin was added in much more.

For the sheet samples according to the examples and comparative examples prepared as described above, evaluation of physical properties of tensile strength and elongation, evaluation of molecular weight reduction, and performance evaluation of freshness were performed.

[Experimental Example]

(1) Evaluation of tensile strength and elongation

Tensile strength and elongation of sheet samples of Example 1 and Comparative Example 1 cut to 25 × 102 mm according to ASTM D 3826 method were measured according to ASTM D 3826-98. The number of samples per sheet was measured 10 times for each measurement item in order to reduce the error for each sheet, and the average value excluding the maximum and minimum values was taken. Load cell was used 50 ㎏, UTM (Universal Testing Machine, Daekyung Tech, Korea) machine was used, the tensile speed of the machine was set to 50 ㎜ / min, the experiment was conducted, and the results are shown in Table 1 below. Did.

[Table 1]

As a result of the experiment, Example 1 showed a tensile strength of 19.0 MPa and an elongation of 295.40%. On the other hand, Comparative Example 1 showed a higher tensile strength and a lower elongation elongation compared to Example 1. This is judged to be a difference in mechanical properties due to the molecular weight of the binder resin, and Example 1 is judged as suitable mechanical properties for use as a food packaging container even though expensive polylactic acid (PLA) is not used.

(2) Molecular weight reduction evaluation

The molecular weight changes of the sheet samples according to Example 1 and Comparative Example 1 were measured. Countries with certification standards for degradable films worldwide include the United States, Sweden, the United Kingdom, Korea, Singapore and the UAE. Among countries that have the above certification standards, except for the UK, which performs sensory testing, other countries conduct molecular weight evaluation, biodegradation evaluation, gel residue test, physical property degradation, and heavy metal test according to the method of ASTM D 6954. Of these, the molecular weight of 10,000 Da or less is the evaluation reference point according to the method of ASTM D 6954 Tier 1 in Sweden and Singapore, and the molecular weight of 5,000 Da or less is the evaluation reference point of Korea and the UAE according to the method of ASTM D 6954 Tier 1. Molecular weight evaluation was conducted by the Korea Apparel Testing and Research Institute according to the method of ASTM D 6954 Tier 1 at 340 nm irradiance and temperature of 50 ° C. for 400 hours, and the results are shown in Table 2 below.

[Table 2]

As a result of the experiment, the molecular weight of 4,023 Da entered after 300 hours in Example 1, while the comparative example 1 shows a relatively high molecular weight level. After 400 hours, Example 1 and Comparative Example 1 show a difference in the molecular weight range. The molecular weight reduction rate in Comparative Example 1 including polylactic acid (PLA) in a higher content was better than in Example 1, and it is determined that the biodegradable polymer polylactic acid (PLA) is a biodegradation result. Comparative Example 1 showed an excellent molecular weight reduction rate compared to Example 1, but the molecular weight after a certain period of time appears lower in Example 1, which is judged to be based on the molecular weight of the first binder resin.

On the other hand, it can be seen that Example 1 has a property suitable for production as a molded article, and has a composition suitable for use as a biodegradable plastic by having excellent biodegradability compared to biodegradable plastics known in the art.

(3) Evaluation of freshness maintenance performance

Using the composition for vacuum forming according to Example 1 and Comparative Example 2 to prepare a food storage container according to a conventional vacuum molding method.

1 is a photograph comparing the storage period of eggs using a vacuum molded product prepared using a composition according to an embodiment of the present invention, in the case of a container manufactured using a freshness retention agent according to the present invention, 15 days under the same conditions While the yolk and white are clearly distinguished after this, it can be seen that in the case of the existing container, corruption is severe.

It is evaluated that this is due to the synergistic antibacterial effect of the functional mineral material and the natural antibacterial agent, and it was confirmed that impregnation of the natural antibacterial agent with the porous material was more effective in the persistence of the antibacterial functional exertion.

Claims (5)

With respect to 100 parts by weight of the total composite decomposition additive composition,
10 to 15 parts by weight of coconut skin;
Waste paper powder 5 to 10 parts by weight;
Organic peroxide 0.01 to 1.0 parts by weight;
Glue 5.0 to 10.0 parts by weight;
1 to 5 parts by weight of freshness retention agent and
A composite decomposition additive composition having a freshness retention function comprising a binder resin having a molecular weight of 3,000 to 5,000 Da.
According to claim 1,
The freshness-retaining agent is a porous material 65 to 75 wt%; Functional minerals 15 to 25 wt%; And 10 to 15 wt% of a natural antibacterial agent.
According to claim 2,
The freshness retention agent is that the natural antibacterial agent is supported on the porous material,
The porous material is one or more selected from the group consisting of mullite, amorphous aluminosilicate, zeolite, and mesoporous silica,
The functional mineral is at least one selected from the group consisting of Xenotime, Gadolinite, and Euxenite,
The natural antibacterial agent is a complex decomposition additive composition having a freshness retention function, characterized in that at least one selected from the group consisting of acid shool, propolis, and chitosan is used.
A composite decomposition additive pellet having a freshness maintenance function prepared from the composite decomposition additive composition having a freshness maintenance function according to any one of claims 1 to 3.
A composite decomposition additive pellet having a function of maintaining freshness according to claim 4; Sheet or vacuum molded product that has the function of maintaining freshness by mixing polymer resin and decomposition aid accelerator

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