KR20180119479A - Multi-degradable polyolefin-based resin composition and manufacturing method of the composition - Google Patents

Abstract

The present invention relates to a multi-degradable polyolefin-based resin. According to the present invention, a master batch and a compound composition which are complexly decomposed in the form of homogeneous pellets can be provided without using expensive biodegradable raw materials such as starch, aliphatic polyester and the like, by adding a small amount of an additive such as a light decomposition agent, an oxidative degradation agent, a microorganism decomposition agent, etc. to a polyolefin resin; mixing the same without using a high-speed stirrer at a temperature maintained at 80°C, but using a dehumidifying agent at room temperature in a non-heated method to obtain a homogeneous mixture; and forming pellets of the mixture by continuously using a melt extruder.

Description

[0001] The present invention relates to a multi-degradable polyolefin-based resin composition and a method of manufacturing the same. More particularly,

More particularly, the present invention relates to a method for producing homogeneous pellets capable of biodegradation by adding a small amount of a dehumidifying agent to a polyolefin resin, will be.

The biodegradable resins developed so far include polylactic acid (PLA) type resins synthesized from starch, corn, milk powder and the like, polycaprolactone (PCL) resins chemically synthesized starting from an epsilon caprolactone monomer and diol (Dicarboxylic acid) -based aliphatic polyester-based resins, polyhydroxybutylate (PHB) produced by in-vivo synthesis of other microorganisms, and the like. These biodegradable resins can be finally biodegraded into water and carbon dioxide due to the action of the enzymes produced by the microorganisms.

The polylactic acid resin is suitable for use as a packaging container because it is less than half the price of an aliphatic polyester and has a good transparency and a high hardness. However, the polylactic acid resin is low in elongation and easily broken by impact, There is a problem that a hole is formed in a portion where the thickness is thinned. In addition, since the heat distortion temperature is low and the bubble stability is poor due to the slow cooling rate, there are many limitations in the portion where the film is produced by blow molding.

The polycaprolactone resin has a disadvantage in that it has poor processability due to its low melting point. The aliphatic polyester resin is more flexible than the conventional plastic product, has a high elongation rate and has a high limit temperature for heat resistance compared to PLA. However, since the price is very high, practical use is delayed. In order to decompose plastics, photodegradation additive, biodegradable resin, thermal decomposition agent, complex decomposition additive and the like are used. Among them, there is a growing interest in complex decomposition which is decomposed by one or more mechanisms.

Korean Patent No. 10-1013453 has produced a complex degradable material using starch. However, since it is not possible to directly use the properties of starch as a plastic product, it is necessary to blend or modify with other materials. However, expensive starch extruder (REX) is needed in the process of using starch plasticizer to modify starch.

In order to produce composite decomposition plastics containing starch, a general universal extruder can not be used and a special extruder for starch must be used. As a conventional technique for plastic composite decomposition, Korean Patent Registration No. 0602385 discloses a complex decomposable thermoplastic polymer composition. However, there is a problem that the amount required for the overall composition of the plastic products to cause sufficient decomposition effect increases the manufacturing cost, and since they are difficult to be molded using the molding machine for mass production, There is a limit in producing a biodegradable film or the like based on these as a main component.

Korean Patent Application No. 1996-64953 discloses a mulching film composition for biological / photolytic agriculture. However, this composition has a low decomposition rate and can be regarded as collapsible rather than degradable. Further, a polymer material such as polycaprolactone or polylactic acid It is difficult to be industrialized due to high manufacturing cost.

US Pat. No. 3,941,759 discloses a plastic composition which can be photodegraded by ultraviolet rays by adding a photosensitizer, which is an organic compound. US Patent No. 3992487 discloses a method of mixing a thermoplastic polymer with a polymer containing a metal ion, Lt; RTI ID = 0.0 > photocatalyst < / RTI > However, the plastic compositions disclosed in these patents have a limitation such that they are decomposed for a long period of decomposition and buried in the soil and are not decomposed under light-free conditions.

Another prior art is to use 24 raw materials in small quantities. For example, the constituents are composed of 55% by weight of calcium carbonate, 24% by weight of synthetic resin, 10% by weight of polyvinyl alcohol and the remaining 10% It consists of 20 kinds of additives. Therefore, the additive amount of each additive is mixed at a temperature of 80 ° C while adding a small amount of not more than 1% by weight, so that the reproducibility can not be secured when the material having a low decomposition temperature is volatilized or scattered.

Also, in the high-speed stirring step of 80 ° C, only one raw material of polyvinyl alcohol is firstly mixed, and then a part of all raw materials are sequentially added and mixed. Then, calcium carbonate and a part of raw materials are separately mixed at room temperature, The method of mixing all of the above materials is adopted. However, since it is necessary to mix the materials in various stages, there is a problem in applying to the continuous production process.

As a result of application in a production plant, it is considered that the dispersion of calcium carbonate is poor, the polyvinyl alcohol is carbonized and attached to the surface of the film, or the compatibility with the polyolefin resin is poor, And the reproducibility can not be secured basically due to such causes.

In the process of mixing the respective raw materials, it is necessary to identify the complicated reaction process between the 24 raw materials. In addition, in the mixing process of the calcium carbonate filler using 55% by weight and the additives, the distribution and dispersion of the filler particles It is an important technological matter to train efficiently so that it occurs homogeneously. Even calcium carbonate dried in the pretreatment step is very hygroscopic, so that it reacts with moisture and gas which may occur in the mixing reaction process of 24 kinds of raw materials and melt extrusion process, There is a risk that one mixed composition can be prepared.

Accordingly, the production equipment commonly used in the art can be used without using the starch material, and the products with good complex decomposition can be used to activate the present biodegradable market by using low cost raw materials.

Korean Patent No. 10-0602385 Korean Patent No. 10-1013453

It is an object of the present invention to provide a method for producing a polyolefin resin which does not use expensive biodegradable raw materials such as preblended or aliphatic polyester based resins but also a method of adding a small amount of additives such as photodegradation, To obtain a homogeneous mixture by mixing them at room temperature without using a high-speed stirrer at 80 DEG C to provide a homogeneous pellet-type complex-decomposed master batch and compound composition continuously using a melt extruder will be.

Sheets, bottles, injection-molded products, etc., which are decomposed by extrusion molding, inflation molding, injection molding, blow molding or the like using the provided composition And a method for producing the same.

In order to achieve the object of the present invention, the present invention provides a process for producing a polyolefin resin, a grafted polyolefin resin, a powdered calcium carbonate, a pelletized calcium carbonate, a dehumidifying agent, a photodegradation initiator, a polyvinyl alcohol, A polyvinyl alcohol plasticizer, an anionic surfactant, a lubricant, and borax.

Preferably, the polyolefin-based resin is a mixture of at least one selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and polypropylene.

Preferably, the grafted polyolefin-based resin is a mixture of at least one selected from the group consisting of grafted low-density polyethylene, grafted high-density polyethylene, grafted linear low-density polyethylene and grafted polypropylene. Decomposable polyolefin-based resin composition.

Preferably, the dehumidifying agent is a mixture of at least one selected from the group consisting of zeolite, bentonite, diatomaceous earth, silica gel, activated carbon, and superabsorbent resin.

According to an embodiment of the present invention, there is provided a composite degradable polyolefin resin composition comprising 200 to 600 parts by weight of a high-density polyethylene resin based on 100 parts by weight of the polyolefin-based resin composition.

According to another embodiment of the present invention, there is provided a composite decomposable polyolefin-based resin composition comprising a complex-decomposable polyolefin-based resin composition composition molded by at least one of extrusion molding, inflation molding, injection molding and blow molding, .

In order to achieve the object of the present invention, there is provided a process for producing polyvinyl alcohol, comprising the steps of: (1) plasticizing polyvinyl alcohol by adding polyvinyl alcohol and a polyvinyl alcohol plasticizer to an agitator and then mixing; (2) The method of producing a polyvinyl alcohol resin composition according to any one of (1) to (3), wherein the plasticized polyvinyl alcohol is a polyolefin resin, a grafted polyolefin resin, a powdered calcium carbonate, , And borax are sequentially added and mixed; And (3) introducing the mixture into an extruder, melt-kneading the mixture, and then cooling the mixture to prepare a masterbatch of the composite degradable polyolefin-based resin composition masterbatch.

According to the present invention as described above, biodegradation is possible by a simple addition without using expensive biodegradable raw materials such as starch and polyester, and extrusion is easy. This can reduce the manufacturing costs of complex degradable plastics, which can activate the biodegradable market and help a large number of environmental problems, thereby expanding market demand. The biodegradable agent of the present invention can be produced at about 40% lower cost than general biodegradable materials using polyethylene and starch.

More specifically, extrusion can be made possible by using a dehumidifying agent instead of starch, pelletized calcium carbonate, grafted low density polyethylene, and plasticized polyvinyl alcohol.

FIG. 1 shows (a) a cumulative amount of carbon dioxide generation curve of a standard material (cellulose), and (b) a biodegradation curve.
Fig. 2 shows (a) the cumulative amount of carbon dioxide generation curve of the biodegradable bag, and (b) the biodegradability curve.

Hereinafter, the present invention will be described in detail.

The composite decomposition process of the complex decomposable plastic of the present invention is carried out by the following steps.

(1) A polyolefin-based resin composition comprising a long-chain carbon-carbon bond.

(2) When the PE wax, sorbitol, and sodium alginate components contained in the composition are degraded after self-decomposition by the enzymatic reaction process, the polyolefin-based resin polymer is degraded due to its biodegradable mass.

(3) the stearic acid components react with the carbon-carbon bonds of the exposed polyolefinic polymer component, some of which are converted to calcium stearate and some of which are partially decomposed to form peroxides or hydroperoxides.

(4) The iron stearate and the magnesium stearate contained in the composition act as an initiator for assisting the initiation of the reaction of the stearic acid component. After this, the iron stearate, magnesium stearate and calcium stearate also act as oxidation promoters, Peroxides and redox reactions are repeated to produce free radicals with high reactivity and autooxidation, thereby initiating radical reactions using light or heat as reaction energy.

(5) Acetyl acetonite, dimethyldithiocarbamic acid, and iron chloride also react with light to generate free radicals, which act as photolysis promoters and initiate radical reactions.

(6) When a radical reaction is initiated, the oxidative decomposition reaction is continuously performed even when there is no light. As a result, the carbon chain cutting and low molecular weight of the thermoplastic resin polymer.

(7) The low-molecular-weight polyolefin resin polymer is present in the form of carboxylic acid, ketone, aldehyde, carboxylic acid and the like which can be easily decomposed.

(8) Oxidation reaction promoting auxiliaries such as calcium carbonate and polyvinyl alcohol contained in the composition absorb moisture of external conditions and provide a moist environment in which microorganisms can actively act, thereby converting into water, carbon dioxide and biomass Disassembly is complete.

Therefore, in order to produce a complex decomposable plastic molded article which can exert oxidative action, autoxidation action, photodegradation action and microbial decomposition action, it is necessary to use a biodegradable raw material, an oxidative raw material, an initiator (oxidation reaction promoter) It should be noted that the raw materials must be included.

Thus, it is possible to produce biodegradable complex degradation products without using expensive biodegradable raw materials such as all pre-selected from the group consisting of starch, modified starch and starch derivatives, PLA, PCL and aliphatic polyester based on chemical synthesis, It has been confirmed that biodegradation is possible by using a small amount of additive such as decomposition of polydisperse, decomposition of acid decomposition and decomposition of microorganism to produce polyolefin. Also, by using a dehumidifying agent, a high-speed stirrer It was confirmed that homogeneous pellets could be produced continuously by using a melt extruder after mixing the stirrer at a room temperature without using it in a non-heating manner to obtain a homogeneous mixture.

In order to achieve the object of the present invention, the present invention provides a process for producing a polyolefin resin, a grafted polyolefin resin, a powdered calcium carbonate, a pelletized calcium carbonate, a dehumidifying agent, a photodegradation initiator, a polyvinyl alcohol, A polyvinyl alcohol plasticizer, an anionic surfactant, a lubricant, and borax.

Preferably, the present invention relates to a polyolefin resin composition comprising 10.0 to 17.2% by weight of a polyolefin resin, 3.7 to 6.1% by weight of a grafted polyolefin resin, 22.4 to 41.6% by weight of powdered calcium carbonate, 14 to 26% by weight of pelletized calcium carbonate, 2.6-2.5 wt.%, Light decomposition 0.96-1.78 wt.%, Initiator 3.52-6.44 wt.%, Polyvinyl alcohol 6.32-11.59 wt.%, Biodegradation or biodegradation 3.93-7.30 wt.%, Polyvinyl alcohol plasticizer 1.22-2.16 wt. 0.21 to 0.39 wt% of an anionic surfactant, 2.1 to 3.9 wt% of a lubricant, and 0.07 to 0.13 wt% of borax.

More preferably from 10.0 to 17.2% by weight of a polyolefin resin, from 3.7 to 6.1% by weight of a grafted polyolefin resin, from 22.4 to 41.6% by weight of powdered calcium carbonate, from 14 to 26% by weight of pelletized calcium carbonate, from 1.4 to 2.6% by weight of zeolite %, Polyvinyl alcohol 6.32 to 11.59% by weight, borax 0.07-0.13% by weight, pigment 0.37-0.6% by weight, PE wax 4.3-7.9% by weight, acetylacetonate 0.015-0.025% by weight, dimethyldithiocarbamic acid 0.70 to 1.17 wt% of dimethyldithiocarbamic acid, 0.30 to 0.52 wt% of ferric chloride, 2.10 to 3.54 wt% of ferric stearate, 1.43 to 2.38 wt% of magnesium stearate, 0.45 to 0.75 wt% of stearic acid , Glycerol monostearate 0.3 to 0.5 wt.%, Polyethylene glycol 0.3 to 0.5 wt.%, Sorbitol 0.079 to 0.128 wt.%, Carrageenan 0.1 to 3.5 wt.%, Glycerol monostearate 0.3 to 0.5 wt. 0.073 to 0.128 wt.% Of methylcellulose methylcellulose (CMC-Na), 0.146 to 0.256 wt.% Sodium lauryl sulfate, 0.073 to 0.128 wt.% Of lauryl benzene sulfonic acid sodium, 0.005 wt.% Of benzoyl peroxide (BPO) To 0.017% by weight, sodium alginate 0.042% to 0.078% by weight, and methyl salicylic acid 0.073% to 0.128% by weight based on the total weight of the polyolefin resin composition.

Raw materials used in the mixing and extrusion processes for producing the molded articles of the present invention are summarized below in the compositions of the present invention. Each raw material is not limited to the use or range described below.

The polyolefin resin may be one or a mixture of two or more selected from the group consisting of low density polyethylene, linear low density polyethylene and polypropylene. Preferably 10 to 17.2% by weight, most preferably 14% by weight. The polyolefin resin is a first low density polyethylene having a melt index of 1.5 to 2.5 g / 10 min, preferably 2.0 g / 10 min. The density has a density of 0.9 to 1 g / cc, preferably 0.910 to 0.925 g / cc, more preferably 0.921 g / cc. The polypropylene is approximately 0.9 to 0.91 g / cc.

The grafted polyolefin resin may be one or a mixture of two or more selected from the group consisting of grafted low density polyethylene, grafted high density polyethylene, grafted linear low density polyethylene, and grafted polypropylene. Preferably 3.7 to 6.1 wt% of the grafted low density polyethylene is used, more preferably 5 wt% is used.

The grafted polyolefin resin is preferably a low density polyethylene grafted with maleic anhydride, and has a melt index of 3.8 to 6.5 g / 10 min, preferably a melt index of 5.0 g / 10 min. This is because the resins have different melt indexes, densities and material properties, and homogeneous mixing is difficult. Addition of a low density polyethylene resin grafted with maleic anhydride makes it possible to improve the mixing properties and physical properties of resins.

A film in which 6.1 weight% or more of low density polyethylene grafted with maleic anhydride is added has a reduced elongation percentage and is broken, and film formation is not smooth when not added. The maleic anhydride LDPE used in the present invention improves the compatibility of the polyvinyl alcohol with the polyolefin resins. In addition, as an application for improving compatibility between resin streams, for example, there is an effect of improving compatibility between low-density polyethylene and high-density polyethylene and polypropylene resin as well as calcium carbonate.

The calcium carbonate filler used in the present invention is used for reducing the manufacturing cost of composite decomposition plastics, enhancing the strength, promoting biodegradability due to calcium carbonate matrix collapse at the time of biodegradation, and the like. In consideration of cost reduction and dispersibility, in the present invention, powdered calcium carbonate 22.4 to 41.6 wt% and pelletized calcium carbonate 14 to 26 wt% were used. Preferably, 32 wt% of powdery calcium carbonate and 20 wt% of pelletized calcium carbonate were used.

20% by weight of the pelletized calcium carbonate (Pellet CaCO3) is composed of 14% by weight of calcium carbonate relative to the total polyolefin resin composition, so that the total amount of calcium carbonate actually added in the present invention is about 46% by weight. If the total amount of calcium carbonate is less than about 30% by weight, the effect of reducing the unit cost is insufficient. When the amount of calcium carbonate is more than about 60% by weight, the amount of the resin is relatively insufficient and the dispersibility is poor. Treated calcium carbonate or a dispersing agent.

The particle size of the powdery calcium carbonate used in the present invention is preferably 0.2 to 5 mu m, more preferably 0.5 to 3 mu m. When particles larger than the above range are used, the particles precipitate and adversely affect the physical properties such as tensile strength. If the particles are too fine, the cost increases and the dispersibility may deteriorate due to agglomeration of the particles while the shearing force increases during the mixing.

The pelletized calcium carbonate is prepared in the form of pellets by separately mixing calcium carbonate and low density polyethylene at a weight ratio of 6 to 8: 2 to 4, preferably 7: 3. The low-density polyethylene is separate from the low-density polyethylene in the complex-decomposable polyolefin-based resin composition, and may be represented by a second low-density polyethylene. When calcium carbonate is mixed only in powder form, it is scattered during mixing or it takes a long time to mix. Therefore, a homogeneous mixture can be prepared by using calcium carbonate in the form of pellets.

The present invention can replace high-cost starch by using a dehumidifying agent, pelletized calcium carbonate, grafted low density polyethylene and plasticized polyvinyl alcohol, and has a high-speed stirrer A Henkel mixer or the like was stirred at room temperature to make a uniform mixed composition. Examples of the dehumidifying agent include zeolite, bentonite, diatomaceous earth, silica gel, activated carbon, quicklime, and superabsorbent resin.

The dehumidifying agent can be prepared by reacting moisture and gas in a mixing reaction process and a melt extrusion process in which calcium carbonate having high hygroscopicity and 24 kinds of additives are temporarily mixed in the present compositions to prevent the problem that a non- Is used. Preferably, zeolites are used which can take advantage of the simple physical adsorption phenomenon of fine and numerous pores formed during the reaction.

In the present invention, zeolite is added in an amount of 1.4 to 2.6% by weight, preferably 2% by weight. Zeolites are capillary pores that can be stored in pores without pumping out water due to the capillary action of the pore structure. It is also a chemically stable natural substance that does not react with other ingredients and is a powder or granular product with a high specific surface area and uniform pores. The product exhibits very low secondary cohesion and high dispersibility in the mixture and can be used at high temperatures such as 700 ° C due to its high thermal stability. As a result, it is possible to mix about 25 kinds of raw materials at room temperature without heating, to obtain a uniform mixed composition, and to solve the reproducibility problem according to the decomposition temperature difference.

In the biodegradation process of the present invention, the polymer chain is converted into a low molecular weight hydrophilic compound by the light decompositions. Due to the hygroscopic action of the hydrophilic polyvinyl alcohol, glycerin, carboxymethylcellulose and calcium carbonate filler, the plastic composition can maintain a humid environment suitable for mold growth. Hydrophilic polymer materials react with water to dissolve and migrate to a wet gel state at the initial stage, but when the time elapses, it becomes a hard gel state and thus can not be an environment optimized for mold. Therefore, when zeolite is used, it reacts with water and adsorbs water in millions of nanoscale capillary pores and does not discharge it, so it can maintain a humid environment.

Examples of the light decomposition include acetylacetonate, dimethyldithiocarbamic acid, and ferric chloride. Acetylacetonate reacts with light to generate free radicals to act as a photolysis accelerator. In the present invention, 0.02% by weight of cobalt triacetylcetonate is used to form ferric stearate or magnesium stearate ) And the like, the ligand action that acts as a crosslinking accelerator is exerted by the effect of the oxidation reaction catalyst. Dimethyldithiocarbamic acid is preferably 0.94% by weight as a photocatalytic accelerator having an offensive odor and an unsuitable hue for producing a transparent film. 0.41% by weight of iron chloride was used. In the present invention, they react with light to generate free radicals to act as a photolysis promoter, thereby initiating a radical reaction.

In the present invention, iron stearate, magnesium stearate and stearic acid were used as initiators. Iron stearate or magnesium stearate serve as initiators to assist in the initiation of the reaction of the stearic acid component. Even after this, iron stearate, magnesium stearate and calcium stearate act as oxidation promoters.

The initiator reacts with peroxides and redox reactions to produce free radicals, which are autoxidized by free radicals with such high reactivity. By the auto-oxidation, light or heat is used as the reaction energy to start the radical reaction. The resin composition of the present invention preferably contains 2.83% by weight of iron stearate and 1.9% by weight of magnesium stearate. Magnesium stearate also acts as a dispersant for calcium carbonate.

Stearic acid is a typical fatty acid glyceride and has a melting temperature as low as about 72 ° C, and also plays a role of regulating photodegradability by producing a metal stearate such as iron stearate, calcium stearate, and zinc stearate. Since the surface of the calcium carbonate hydrophilic particles is coated to convert into a hydrophobic property and serves both as a lubricant and as a biodegradation agent, 0.6 wt% is used in the present invention.

The resin composition of the present invention comprises a polyvinyl alcohol and a polyvinyl alcohol plasticizer. As the polyvinyl alcohol plasticizer, glycerin, glycerol, benzoyl peroxide (initiator), and carboxyl methyl cellulose are used. The glycerin, glycerol, benzoyl peroxide, and carboxymethyl cellulose are used as plasticizers for polyvinyl alcohol, and exhibit biodegradation or biodegradation.

Glycerol can preserve the complex-decomposable resin composition in a gel state, but because of its inherent viscosity, it is preferable to complete the plasticization to 0.4% by weight. Glycerin was added in an amount of 2.8% by weight for optimal polyvinyl alcohol plasticization. Benzoyl peroxide (BPO) contains 0.013 wt% as a representative peroxide.

Benzoyl peroxide serves primarily to activate polyvinyl alcohol plasticizers and, when mixed with polyolefin resins, initiates the grafting of maleic anhydride. The peroxide is selected from the group consisting of benzoyl peroxide, di-tributyl peroxide, tributyl hydroperoxide, n-cumyl peroxide, 2,5-dimethyl-2,5-di (t- butyl peroxide) (t-butylperoxy-isopropyl) benzene, and the present invention is not limited thereto.

The biodegradation or biodegradation of the resin composition of the present invention includes PE wax, sorbitol, sodium alginate, glycerin, glycerol, polyethylene glycol, carboxymethyl cellulose, methyl salicylic acid and stearic acid.

In the present invention, 0.1 weight% of sorbitol and 0.1 weight% of methylsalicylic acid were used as biodegradable raw materials which can be degraded by themselves. Carboxymethylcellulose was also used for biodegradation or biodegradation and 0.1 wt% in CMC-Na. Since alginic acid does not dissolve in water, it is often used in the form of water-soluble sodium alginate, and 0.06% by weight is used for microbial degradation. Also, polyethylene glycol is used as a yeast culture agent, and 0.4 wt% is used in the present invention.

The present invention relates to a process for producing a microorganism which is free from microbial decomposition starting materials and which is separately subjected to a polymerization reaction including an esterification reaction and a polycondensation reaction, In this process, microbial disintegrants are used for emulsifiers, stabilizers, thickeners, crosslinking agents, crosslinking accelerators and polyvinyl alcohol plasticizers because they are a simple manufacturing method used in a method of extrusion after mixing.

The PE wax has an advantage of a low melting point. When the composition is manufactured by using an extruder, the PE wax exhibits a lubricating function and has a function of self-biodegrading at a low molecular weight. PE wax, stearic acid, and magnesium stearate are used as lubricant. When fatty acid-based lubricant is used, it has the advantage of showing affinity with inorganic materials such as calcium carbonate and has an advantage of surface modification by coating hydrophilic inorganic material. And facilitates the mixing of the additives.

The lubricant is an additive which is used to reduce the friction between the raw materials of the composition in the raw material mixing process or the melt extrusion process and smoothen the friction between the raw materials of the composition. When inorganic materials such as calcium carbonate are added in large amounts, the temperature is increased due to frictional heat with the screw. It is used to carbonize the organic additive and to prevent the occurrence of defects by pressing on the surface of the screw. In another method, an antioxidant is used to solve this problem.

Borax is a material that can be used to modify polyvinyl alcohol to hydrophobicity. In the present invention, it acts as an emulsifier. It is well soluble in glycerin, and its content is 0.1% by weight.

Anionic surfactants include sodium lauryl sulfate and lauryl benzene sulfonic acid sodium. As a typical anionic surfactant used as an emulsifier and a dispersant, it is generally adsorbed at the interface between hydrophilic and hydrophobic raw materials, and its surface tension is reduced and mixed to improve compatibility. In the present invention, 0.2 wt% of sodium laurylsulfate was added, and 0.1 wt% of sodium laurylbenzenesulfonate was added.

The composition according to the present invention may further comprise a decomposition period adjusting agent capable of controlling the decomposition period depending on the application, and the amount thereof is preferably 0.001 to 5 parts by weight per 100 parts by weight of the matrix resin. If the amount is less than 0.001 parts by weight, the effect of controlling photodegradation is negligible. If the amount is more than 5 parts by weight, photodegradation can not proceed sufficiently within one year.

The master batch composition manufacturing method of the present invention will be described.

A raw material preparing step of preparing a master batch composition of the present invention by metering; After adding polyvinyl alcohol, benzoyl peroxide, glycerin, glycerol, and carboxymethylcellulose raw materials together to a stirrer, the mixture is mixed at 4 to 6 minutes, preferably 5 minutes, at 600 to 1000 RPM at 1 to 30 DEG C to prepare a plasticized modified polyvinyl A polyvinyl alcohol plasticization step to obtain an alcohol mixture; A mixing step of sequentially charging all of the remaining raw materials into the plasticized modified polyvinyl alcohol mixture and uniformly mixing them; The mixture obtained through the mixing step is continuously adjusted to a temperature of from 100 to 170 ° C., and the mixture is introduced into an extruder and melt-kneaded. After cooling slowly at 1 to 30 ° C. or quenched in a cooling water bath of 1 to 10 ° C., ≪ / RTI >

Unlike general thermoplastic resins, polyvinyl alcohol resins have very similar melting points and thermal decomposition temperatures, making it impossible to form films by a simple heating and melting method. The particles precipitated on the surface of the film drawn from the inflation process after manufacturing the compound using the masterbatch were analyzed with polyvinyl alcohol and plasticization was required to remove it. Since polyvinyl alcohol has low tensile strength and is hydrophilic, its compatibility with polyolefin resins is very weak and polyvinyl alcohol is added after plasticizing due to strong hygroscopicity of calcium carbonate added together.

If an extruder having a plurality of feed ports for feeding raw materials is used, plasticization and melt-kneading can be simultaneously carried out in a batch process without preliminarily plasticizing in an agitator. That is, the polyvinyl alcohol and the polyvinyl alcohol plasticizer are fed through the first inlet by using an extruder having a plurality of inlets in series along the advancing direction of the extruder to plasticize the polyvinyl alcohol. By injecting the remaining components of the resin composition through another inlet downstream of the plasticization, mixing, thermal fusion and kneading of the components can be performed at the same time.

The polyvinyl alcohol plasticizer may be selected from the group consisting of glycerin, glycerol, benzoyl peroxide, and carboxymethylcellulose. The plasticizer and polyvinyl alcohol are added together and mixed for 4 minutes to 6 minutes, preferably 5 minutes, to obtain plasticized polyvinyl alcohol. By preliminarily plasticizing the polyvinyl alcohol in this manner, a homogeneous mixed composition can be obtained between the polyvinyl alcohol and the remaining raw materials of the resin composition, and mutual fusibility and bonding strength can be increased.

The polyolefin is poorly compatible with polyvinyl alcohol, so that when the polyolefin and polyvinyl alcohol are mixed, the mechanical properties of the molded article are deteriorated by forming a separate interface at the interface between the respective raw materials. Therefore, in order to improve the compatibility of polyvinyl alcohol and polyolefin, a non-polar functional group compatible with polyolefin and a polar functional group compatible with polyvinyl alcohol may be used as a compatibilizer simultaneously in one molecular unit.

After the mixing step, low density polyethylene (LDPE-g-MA, melt index: 5 g / 10 min) grafted with maleic anhydride is added through the inlet during the melt extrusion process. Low-density polyethylene grafted with maleic anhydride is added, melt-kneaded and cooled to prepare a master batch in the form of pellets. A film in which 6.1 weight% or more of low density polyethylene grafted with maleic anhydride is added has a reduced elongation percentage and is broken, and film formation is not smooth when not added.

The method of producing a compound batch of the present invention will be described.

200 to 600 parts by weight, preferably 400 parts by weight, of high-density polyethylene resin is further mixed with 100 parts by weight of the master batch composition, melt-extruded and then cooled to prepare a compound batch in the form of pellets. This is an additive amount range in which the complex degree of decomposition can be excellently exerted. If 200 parts by weight or more is mixed, the complex degree of decomposition is reduced. If the amount is less than 600 parts by weight, the cost is not preferable.

Preferably, the high density polyethylene may have a melt index of 0.04 to 0.05 g / 10 min and a density of 0.9 to 1 g / cc. More preferably, the high density polyethylene resin has a melt index of 0.045 g / 10 min and a density of 0.941 to 0.970 g / cc, especially 0.956 g / cc. If the melt index is high, the injection moldability is excellent. If the melt index is low, it is advantageous for extrusion. Therefore, a suitable range of 0.04 to 100 g / 10 min can be selected depending on the molding method such as extrusion and injection and raw materials.

A method for producing various molded articles from the master batch or compound composition of the present invention will be described.

Sheets, bottles, injection-molded products, etc. by a method such as extruding molding, inflation molding, injection molding, blow molding or the like using the master batch or compound composition A variety of molded articles can be manufactured by using molding machines and the like manufactured by the industry. In particular, the composition of the present invention can be used for films such as disposable plastic bags, plastic shopping bags, mulching films, bags for food waste composting, which can be produced by an extrusion blowing method, disposable cups, trays, Fork and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

According to an embodiment of the present invention The composite decomposing polyolefin resin composition of the present invention comprises 14% by weight of low density polyethylene (LDPE), 5% by weight of grafted LDPE (LDPE-g-MA), 32% by weight of calcium carbonate, pelletized calcium carbonate 0.5 wt% of white pigment, 6 wt% of PE wax, 0.02 wt% of acetylacetonate, 0.94 wt% of dimethyldithiocarbamic acid, 0.41 wt% of ferric stearate, 2.83 wt% of ferric stearate By weight of stearic acid, 1.9% by weight of magnesium stearate, 0.6% by weight of stearic acid, 9.4% by weight of polyvinyl alcohol (PVA), 2.8% by weight of glycerine, 0.4% by weight of glyceryl monostearate, , 0.4 weight% of glycol (PEG), 0.1 weight% of sorbitol, 0.1 weight% of borax, 0.1 weight% of carboxymethylcellulose (CMCNa), 0.2 weight% of sodium lauryl sulfate, lauryl benzene sulfonic acid sodium). 1% by weight of benzoyl peroxide, 0.013% by weight of benzoyl peroxide (BPO), 0.06% by weight of sodium alginate, 0.1% by weight of methyl salicylic acid and 2% by weight of zeolite.

20% by weight of pelletized calcium carbonate (Pellet CaCO3) in the polyolefin resin composition Since 6% by weight of the low-density polyethylene is contained in the constituent component, the total amount of the low-density polyethylene is substantially 20% by weight. In addition, in the present invention, 5% by weight of low-density polyethylene modified with maleic anhydride (LDPE-g-MA) is further added.

Example 1 Master batch preparation of complex-decomposable polyolefin-based resin

940 gr of polyvinyl alcohol, 1.3 gr of benzoyl peroxide, 280 gr of glycerol, 40 gr of glycerol and 10 gr of carboxymethyl cellulose were added to the agitator and mixed at room temperature for about 5 minutes at 600 to 1000 RPM to obtain a plasticized modified polyvinyl alcohol mixture, , 1400 gr of low density polyethylene (Hanwha 830, melt index: 2 g / 10 min, density: 0.921 g / cc), 3200 gr of calcium carbonate (FC-1), 2000 gr of pelletized calcium carbonate, 50 gr of pigment (R 996 / 10 g of sodium lauryl benzenesulfonate, 10 g of sodium lauryl benzenesulfonate, 10 g of sodium lauryl benzenesulfonate, 10 g of sodium lauryl benzenesulfonate, 10 g of sodium lauryl benzenesulfonate, 10 g of sodium lauryl benzenesulfonate, 500 gr of grafted low density polyethylene (melt index: 5 g / 10 min) was mixed with 1.3 gr of benzoyl peroxide, 6 gr of sodium alginate, 1 gr of methyl salicylic acid, 200 gr of zeolite (APNC 20) It was then further mixed for 50 minutes at 600 ~ 1000 RPM at room temperature conditions. The resulting mixture was continuously fed into a twin-screw extruder composed of 10 zones, melted and kneaded at a temperature of 100 to 170 DEG C, and then cooled to prepare a master batch in the form of pellets.

Example 2. Compound batch preparation of complex-degradable polyolefin-based resin

(Lotte FL7100, melt index: 0.045 g / 10 min, density: 0.956 g / cc) was further added to 10 kg of the master batch prepared in Example 1 to obtain a melted Kneaded and then cooled to prepare a compound batch in the form of pellets.

Example 3: Preparation of complex-decomposable polyolefin-based resin film

50 kg of the compound batch prepared in Example 2 was used to produce a plastic bag using a conventional film molding machine.

Biodegradability of biodegradable plastic bag was evaluated by FITI test institute. "KS M ISO 14855-1 Determination of aerobic biodegradation of plastic materials under composting conditions: Method by carbon dioxide analysis - Part 1 The biodegradability of the samples was determined by titration in a general manner. Table 1 shows that the volatile solid content, TOC, organic carbon ratio and ThCO2 are similar to each other.

division Dry solid content (%) Volatile Solid Content (%) TOC (%)

(g/g)Organic carbon ratio
C

(g / g) ThCO

(g / vessel) Dry preparation Wet preparation Standard material
(cellulose) 75.4 87.3 83.3 44 0.461 25.931 Biodegradable envelope 99.5 85.6 85.3 45 0.452 27.415

In addition, the amount of carbon dioxide generated in the composting condition was measured by a titration method to measure the aerobic biodegradability. Results of measurement for 55 days The biodegradability of the test substance in relation to the standard substance is shown in Table 2, FIG. 1, and FIG. 2, and cumulative amount of carbon dioxide generation and biodegradation curve are shown for each sample.

division Average biodegradability (%) calculated by carbon dioxide emission Test period (day) Observations Standard material (cellulose) 84.94 45 No specific information such as water content, color, odor, etc. Biodegradable envelope 35.57 45 No specific information such as water content, color, odor, etc. Biodegradability (%) of the test substance to the standard substance Biodegradable envelope 41.87

Table 2 demonstrates that the biodegradable envelope has an excellent biodegradability of 41.87% compared to the reference material. 1 is a graph showing a cumulative amount of carbon dioxide generation of a cellulose (a), (b) a biodegradation curve, (b) a biodegradation curve of the biodegradable envelope, It is understood that about 45% of the standard material has biodegradability.

Example 4 Recycling Extrusion Experiment of Biodegradable Plastic Bag of Complex Degradable Polyolefin

8 kg of high density polyethylene pellet type resin (Lotte FL7100, melt index; 0.045 g / 10 min, density; 0.096 g / cc) purchased as a new type in the market, and a recycled envelope using at least one commercially available HDPE standard envelope And 0.5 kg of a biodegradable plastic bag as a molded product completed in Example 3 were mixed and a plastic bag was produced using a conventional film molding machine.

Table 3 shows the physical properties of the recycled plastic bag, which is a completed molded product, as measured by KPS M 1013 and KPS M 1015, with respect to tensile strength, elongation, and tear strength after being submitted to the FITI test institute.

Comparative Example 1. Recycling extrusion experiment of PLA biodegradable plastic bag

In addition to the 8 kg of the high-density polyethylene pellet-type resin used in Example 4, 1.5 kg of a recycled envelope using at least one commercially available HDPE envelope and 80 g of commercially available PLA biodegradable plastic bag (Saehan Polymer Saehan Eco Shopping Bag) And tried to produce a plastic bag using a conventional film forming machine. However, in the extrusion process, an odor that melts in the heat of the envelope was generated, and the extrusion die was unable to extrude the melt even though the extruder was overloaded.

Comparative Example 2. Recycling Extrusion Experiment of General Plastic Bag

8 Kg of a commercially available HDPE plain plastic bag was re-melt extruded using a conventional film molding machine to produce a plastic bag and the properties were measured in the same manner as in Example 4.

Example
(Sample certificate number) Tensile strength (N / mm 2) Elongation (%) Notch tear strength (N / mm) usually Fold Example 4
(#2) 59.3 400 117 102 Comparative Example 2
(# 3) 43.1 338 86 81 Comparative Example 1
(PLA recycling bag) Impossible to extrude

Table 3 demonstrates that the biodegradable plastic bag according to the present invention is highly recyclable.

In the art of producing general plastic bags, a certain amount of excess is generated during the altar process. In order to recycle the plastic bags, 10 to 20 parts of the extra bag is further mixed with 100 parts by weight of the high density polyethylene pellet resin as the main material of the plastic bag, .

In Comparative Example 1, when the PLA recycling bag is added to the existing high-density polyethylene bag, the re-melt extrusion can not be performed and it can not be recycled. As a result, a separate disassembly for biodegradation must be additionally installed .

On the other hand, the physical property results of Example 4 are similar to those of the general plastic bag of Comparative Example 2, despite being a recycled plastic bag obtained by adding the biodegradable plastic bag of the present invention to a conventional commercialized plastic bag, .

The composite degradable polyolefin-based biodegradable plastic bag according to the present invention can be remelted to produce a finished molded product, thus solving the problems of recycling conventional biodegradable plastics and reducing cost.

Having described specific portions of the present invention in detail, those skilled in the art will appreciate that these specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (7)

A polyolefin resin, a grafted polyolefin resin, a powdered calcium carbonate, a pelletized calcium carbonate, a dehumidifying agent, a light decomposition initiator, a polyvinyl alcohol, a biodegradation or biodegradation agent, a polyvinyl alcohol plasticizer, an anionic surfactant, , And borax. ≪ / RTI >
The method according to claim 1,
Wherein the polyolefin-based resin is a mixture of at least one member selected from the group consisting of low-density polyethylene, linear low-density polyethylene, and polypropylene.
The method according to claim 1,
Wherein the grafted polyolefin resin is a mixture of at least one selected from the group consisting of grafted low density polyethylene, grafted high density polyethylene, grafted linear low density polyethylene and grafted polypropylene. Resin composition.
The method according to claim 1,
Wherein the dehumidifying agent is a mixture of at least one selected from the group consisting of zeolite, bentonite, diatomaceous earth, silica gel, activated carbon, and superabsorbent resin.
The method according to claim 1,
Wherein the polyolefin resin composition further comprises 200 to 600 parts by weight of a high-density polyethylene resin based on 100 parts by weight of the polyolefin resin composition.
6. The method of claim 5,
Wherein the composite degradable polyolefin-based resin composition is molded by at least one of extrusion molding, inflation molding, injection molding and blow molding using the complex-decomposable polyolefin-based resin composition compound.
(1) plasticizing polyvinyl alcohol by adding a polyvinyl alcohol and a polyvinyl alcohol plasticizer to a stirrer and then mixing;
(2) The method of producing a polyvinyl alcohol resin composition according to any one of (1) to (3), wherein the plasticized polyvinyl alcohol is a polyolefin resin, a grafted polyolefin resin, a powdered calcium carbonate, , And borax are sequentially added and mixed; And
(3) introducing the mixture into an extruder, melt-kneading the mixture, and then cooling the master-batch.

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