KR20140117948A - Method for manufacturing naturally degradable master batch and Method for manufacturing naturally degradable film using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a naturally degradable master batch and a method for manufacturing a naturally degradable mulching film. The method for manufacturing a naturally degradable master batch comprises: a first coating step of coating the surface of an inorganic filler with a biodegradable resin to form a first coating material; a second coating step of coating the surface of the inorganic filler with a photolysis agent to form a second coating material; a mixing step of mixing the first coating material and the second coating material with plant fiber powder and a polyolefin resin to prepare a mixture; and a pellet step of making the mixture into a pellet. The method for manufacturing a naturally degradable mulching film comprises: a preparing step of preparing a synthetic resin base material for manufacturing a naturally degradable master batch and mulching film; a mixing step of mixing the naturally degradable master batch with the synthetic resin base material to make an admixture; and a molding step of manufacturing a film by extruding the admixture.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for producing a naturally degradable masterbatch, and a method for manufacturing the naturally degradable masterbatch using the naturally degradable masterbatch,

The present invention relates to a process for producing a naturally degradable masterbatch and a process for producing the naturally decomposable mulching film using the same, and more particularly to a process for preparing a naturally degradable masterbatch having excellent mechanical properties, will be.

In general, mulching film covers the roots of crops to prevent crops in winter due to the synergistic effect of temperature and to inhibit water evaporation in the soil, thus facilitating the cultivation of crops. Traditionally, straw has been used, but since the mid 1980's Polyethylene film.

Polyethylene film has excellent properties in terms of light transmittance, synergy effect on temperature, weed control power and strength, but it does not decompose, and there are problems such as adverse effect on soil and water quality environment unless collected by adding labor force.

To improve this, eco-friendly mulching paper that does not require collection work and has no soil and water pollution has been developed and in use. However, in the case of such a mulching paper, since the strength of the sheet is weak, the thickness of the sheet must be made thick, and therefore, the flexibility of the sheet is poor, resulting in problems in workability and coating. In addition, paper has very poor tensile strengths for mechanical workability and wet strength for use in fresh water conditions compared to vinyl films.

Therefore, there is a demand for the development of eco-friendly mulching materials having natural mechanical properties and controllability of vinyl films and natural degradability of paper.

Korean Patent No. 10-0603073 (Jul. 12, 2006)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a plant fiber, which is excellent in photodegradability and biodegradability by using a plant fiber powder, Decomposable masterbatch, and a method for producing the naturally degradable mulching film using the same.

In order to accomplish the above object, the present invention provides a method for preparing a biodegradable masterbatch comprising a first coating step of coating a surface of an inorganic filler with a biodegradable resin to form a first coating, a step of coating the surface of the inorganic filler with a photodegrading agent A second coating step of forming a second coating, a mixing step of mixing the first coating and the second coating with a plant fiber powder and a polyolefin resin to form a mixture, and a granulation step of granulating the mixture.

The biodegradable resin may be at least one selected from starch, polyethylene succinate (PBS), polybutylene-adipate copolymer, polycaprolactone, and polylactic acid.

The light decomposition release may be at least one selected from stearin, stearic acid, and stearoiodolane.

The method for producing a naturally degradable mulching film according to the present invention comprises the steps of preparing a natural degradable masterbatch and a synthetic resin base material for manufacturing a mulching film according to a manufacturing method according to an embodiment of the present invention and mixing the natural degradable masterbatch with the synthetic resin base material, And a molding step of producing a film by extrusion molding the mixed material.

The synthetic resin base material includes 0.1 to 0.2 parts by weight of an antioxidant, 0.1 to 0.2 parts by weight of an ultraviolet absorber, 1 to 2 parts by weight of an ultraviolet scattering agent, 0.5 to 3 parts by weight of an insect repellent and 0.5 to 3 parts by weight of an anti- , And the base resin may be polyethylene or polypropylene.

According to the method for producing a naturally degradable masterbatch according to an embodiment of the present invention and the method for producing a naturally degradable mulching film using the naturally degradable masterbatch, the plant fiber powder is excellent in photodegradability and biodegradability, and the binding force between the inorganic filler and the base resin is enhanced A mulching film excellent in mechanical properties and workability can be produced.

In addition, the decomposition period of the naturally degrading mulching film can be controlled according to the growing environment of the mulching or the growth period of cultivated crops protected by mulching.

1 and 2 are graphs showing changes in physical properties during the coating period of the naturally degradable mulching film according to the embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the drawings, the same components are denoted by the same reference symbols as possible. Further, the detailed description of known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated.

First, a method of manufacturing a spontaneous degradable masterbatch according to an embodiment of the present invention includes a first coating step, a second coating step, a mixing step, and a papermaking step.

The first coating step is a step of coating the inorganic filler used in the method for producing the spontaneously decomposable mulching film with the biodegradable resin to form the first coating.

The inorganic filler is a substance to be added to the purpose of preventing, reinforcing and increasing the aging of the plastic, and silicon dioxide, calcium carbonate, zeolite, talc, silica, kaolin, barium sulfate, calcium oxide or a mixture thereof can be used. In particular, a silicon dioxide-based inorganic filler is more preferable considering the color of the mulching film to be produced. In general, the inorganic filler is not compatible with the non-polar polyolefin component and is easily peeled off and is not compatible with the biodegradable resin. This problem is solved by coating a biodegradable resin on the surface of an inorganic filler through heat treatment in the present invention.

As the biodegradable resin, all conventionally known biodegradable resins may be used alone or in combination. Examples of such a biodegradable resin include at least one selected from starch, polybutylene succinate (PBS), polybutylene-adipate copolymer, polycaprolactone and polylactic acid, and their modified forms can be used in various ways . Such a biodegradable resin has good compatibility with polyolefin, thereby preventing the inorganic filler from being separated or desorbed during processing, thereby enhancing the processing stability. On the other hand, since such a biodegradable resin is easily decomposed by moisture, the decomposed site serves as a void and the bonding force between the base resin and the inorganic filler is weakened, and the decomposition of the polyolefin resin can easily occur as the inorganic filler is desorbed.

The coating process may be performed by mixing the melted biodegradable resin and the inorganic filler by means of high speed kneading while stirring and drying the remaining material through the drying furnace to coat the biodegradable resin on the surface of the inorganic filler to form the first coating .

The first coating step may be performed, for example, by mixing 10 to 200 parts by weight of the biodegradable resin with 100 parts by weight of the inorganic filler and heat treating the mixture at 70 to 200 DEG C for 1 to 30 minutes.

In this case, the heat treatment temperature is a temperature at which the biodegradable resin can be coated in a sufficiently melted state, and may vary depending on the type of the biodegradable resin. However, since most biodegradable resins can be sufficiently melted in the temperature range, .

The second coating step is a process of forming a second coating by coating the inorganic filler used in the method of manufacturing the spontaneously decomposable mulching film with a photopolymerization agent.

The inorganic filler is a substance to be added to the purpose of preventing, reinforcing and increasing the aging of the plastic, and silicon dioxide, calcium carbonate, zeolite, talc, silica, kaolin, barium sulfate, calcium oxide or a mixture thereof can be used. In particular, a silicon dioxide-based inorganic filler is more preferable considering the color of the mulching film to be produced. In general, the inorganic filler is not compatible with the non-polar polyolefin component and is easily peeled off and is also incompatible with the decomposition of the photodegradation. This problem is solved in the present invention by coating the surface of the inorganic filler with a light decomposition agent through heat treatment.

The light decomposition release may be at least one selected from stearin, stearic acid, and stearoiodolane. Such a light decomposition release is good compatibility with polyolefin and biodegradable resin, thereby preventing inorganic filler from being separated or desorbed during processing, thereby improving the processing stability. On the other hand, since the decomposition of such a photodefiner is easily caused by the sunlight, the decomposed site serves as a pore, so that the bonding force between the base resin and the inorganic filler is weakened and the decomposition of the polyolefin resin can easily occur as the inorganic filler is desorbed.

The coating process may be performed by high speed kneading while mixing and agitating the melted photodegradation and inorganic filler, and drying the remaining material through a drying furnace to form a second coating by coating the surface of the inorganic filler with photodegradation.

 The second coating step may be carried out, for example, by mixing 30 to 200 parts by weight of the light decomposable material with 100 parts by weight of the inorganic filler and heat treating the mixture at 100 to 150 ° C for 1 to 30 minutes.

In this case, the heat treatment temperature is a temperature at which the photodegrader can be coated in a sufficiently melted state, and may be varied depending on the kind of the photodegradation. However, since the photodefination used in the present invention can be sufficiently melted in the temperature range, .

The mixing step is a step of mixing the first coating obtained in the first coating step and the second coating obtained in the second coating step with the plant fiber powder and the polyolefin resin.

 The plant fiber powder is a material that further enhances the biodegradability of the final product. As the main constituent, plant fiber materials such as rice hull, corn bran, bamboo, sugar cane, straw, pulp, May be used alone or in combination of two or more. The plant fiber powder used in this case is preferably a powder having a size of 50 to 300 mesh, which is suitable for kneading with the resin and for decomposing the final product.

The polyolefin is preferably polypropylene, polyethylene or a mixture thereof, and various types can be used without limitation. Specific examples of such examples include polypropylene, low density polyethylene, linear low density polyethylene, a mixture of low density polyethylene and linear low density polyethylene, or high density polyethylene.

For example, the first coating material and the second coating material are mixed in an amount of 10 to 200 parts by weight and 50 to 300 parts by weight, respectively, based on 100 parts by weight of the polyolefin resin. When mixed in the above range, photodegradability and biodegradability can be exerted smoothly. Other additives which can be used in the field to which the present invention belongs, for example, antioxidants, dispersants, colorants and the like can be added variously according to the required quality. The plant fiber powder is preferably used in an amount of 1 to 200 parts by weight based on 100 parts by weight of the polyolefin resin, and the plant fiber powder can be modified according to the required characteristics of the final product.

In the granulation step, the raw material mixture is fed to an extruder, firstly heated at 190 to 200 ° C, secondarily heated at 210 to 220 ° C for the firstly heated raw material mixture, 180 The mixture is heated at ~ 190 ° C for the third time, and the thirdly heated mixed raw material is heated at 230 to 240 ° C for the fourth time to melt and melt the mixture. However, the temperature range is only one example, and a typical engineer can vary the heating step according to the required characteristics of the product and the like. The extruder to be used is not particularly limited and a uniaxial extruder or a twin-screw extruder can be used. In particular, a twin-screw extruder can be used in both the co-rotating direction and the bidirectional rotation. However, in order to prevent the decomposition of the biodegradable resin, More preferable. The extrudate is passed through a cooling bath containing cooling water, preferably cooling water in the range of 10 to 30 占 폚 for about 10 to 30 seconds and cut into a pellet form. The granules thus produced are subjected to dehumidification drying to obtain a final granulation by setting the water content to 1000 ppm or less, preferably to 500 ppm or less.

A method of manufacturing a naturally degradable mulching film according to an embodiment of the present invention includes a preparation step, a mixing step and a molding step.

The preparation step is a step of preparing a natural degradable master batch and a synthetic resin base material for manufacturing a mulching film.

The spontaneously degradable masterbatch is formed by mixing the first coating material and the second coating material with a plant fiber powder and a polyolefin resin and extruding them into a pellet form, wherein the first coating material is formed by coating the surface of the inorganic filler with a biodegradable resin , The second coating may be formed by coating the surface of the inorganic filler with a photodegradable resin. Explanations are the same as those of the natural degradable masterbatch according to another embodiment of the present invention.

The second coating may be mixed at different mixing ratios with the first coating depending on the growing environment, such as the amount of sunshine to be mulched. There is a big difference in the amount of sunshine for each area to be mulched. For example, in Jeju city, the average annual amount of sunshine is 1,854.1 hours per year, which is 700 times less than 2,550.5 hours in Yeongdeok, Kyongbuk. Therefore, when mulching the mulching film having the same photodegradation performance as the Jeju City and Yeongdeok located in different regions of the sunshine, there is a difference in the completion period of the natural decomposition of the mulching film. Even in the same area, it is inefficient to use a mulching film having the same photodegradation performance despite the difference in the amount of sunshine depending on the growth environment such as the location of the previous crop and the cultivation method of the crop. Therefore, the mulching film to be used for the low-sunlight mulching film is prepared by increasing the content of the first coating coated with the biodegradable resin in order to compensate for the small amount of the sunshine, and the mulching film to be used for the full- It is preferable to prepare by increasing the content of the coating. Also, if the mulching film is prepared by varying the content of the second coating according to the amount of sunshine, it is possible to systematically and efficiently control weeds and protect the environment by providing customized mulching films for each region and each farm, have.

Synthetic resin base materials include antioxidants, ultraviolet absorbers, ultraviolet scattering agents, insect repellents and anti-seizure agents in the base resin.

The base resin is polypropylene, polyethylene or a mixture thereof, and various kinds can be used without limitation. Specific examples of such examples include polypropylene, low density polyethylene, linear low density polyethylene, a mixture of low density polyethylene and linear low density polyethylene, or high density polyethylene.

The antioxidant is selected from the group consisting of methylene (3,5-di-tertiary-butyl-4-hydroxyphenyl) propionate and diethyl cyanobutyl- Di-tertiary-butyl-hydroxy toluene may be used. Examples of the ultraviolet absorber include tetra-methyl-pyrrolidinyl-sebacate, ultraviolet scattering agents such as titanium dioxide ), Alkyl aminobenzoate as an insect repellant and permethrin as an emollient may be used. In consideration of the physical properties of the resin composition and the effect of addition of each additive, the content of these additives is preferably 0.1 to 0.2 parts by weight of an antioxidant, 0.1 to 0.2 parts by weight of an ultraviolet absorber, 0.5 to 3 parts by weight of an insect repellent, and 0.5 to 3 parts by weight of a detergent.

The mixing step is a step of mixing the natural degradable master batch with the synthetic resin base material to form a mixed material.

10 to 20 wt% of the synthetic resin base material is mixed and 80 to 90 wt% of the natural decomposable masterbatch is mixed. Mixing ratios may vary depending on the average growth period of the crops grown at the moment where the spontaneous degradable mulching film is mulched. Growth periods of the various crops are different, but generally mulching is done using the same mulching film, so the mulching film remains ungraded after harvest. In this case, it is difficult to efficiently manage all of the mulching films, such as collecting mulching films, by adding additional labor before sowing the next crop. The method for producing a naturally degradable mulching film according to the present invention can provide a customized mulching film for various crops by controlling the content of the naturally degradable master batch such as increasing the content of the naturally degradable master batch in the case of a crop having a long growing period.

On the other hand, naturally degradable mulching films of various colors can be prepared by adding colored pigments, carbon black or fine charcoal powder. In the case of addition of fine charcoal powder, the mulching film is decomposed and the effect of improving the soil adsorption ability can be expected such that the ability of adsorption of roots by char is improved when the fine charcoal powder is added.

The forming step is a step of producing a film by extruding the mixed material.

In the extrusion process, a mixture of a synthetic resin base material and a natural decomposable master batch in a granular form is injected into a sheet extruder and melted to form a gel, passed through a roller and a roller to form a sheet, And stretched in the range of 4 to 10 times in length to prepare a film. The thickness of the produced film is preferably 10 to 100 mu m. If the thickness of the film is less than 10 탆 or 100 탆 or more, economical efficiency is deteriorated due to difficulty in manufacturing and increase in use of raw materials. The naturally degradable mulching film to be produced can form a plurality of fine pinholes, thereby improving the air permeability while preventing the excessive humidification of the soil.

Hereinafter, the present invention will be described in more detail by way of examples, but the scope of the present invention is not limited by the examples.

[Example 1]

100 parts by weight of silicon dioxide was used as an inorganic filler, and 100 parts by weight of polybutylene succinate (PBS) as a biodegradable resin was mixed and heat-treated at 120 占 폚 for 1 to 30 minutes to prepare polybutylene succinate To form a coated first coating. Specifically, in the coating process, the molten polybutylene succinate and the silicon dioxide are melted at the set temperature, and the mixture is stirred and kneaded at high speed, and the remaining material is dried through a drying furnace to form polybutylene succinate Lt; / RTI >

Subsequently, 100 parts by weight of silicon dioxide was used as an inorganic filler, 100 parts by weight of stearin was mixed with 100 parts by weight of the inorganic filler, and the mixture was heat-treated at 120 DEG C for 20 minutes to form a second coating on the surface of silicon dioxide . Specifically, silicon dioxide and stearin were mixed at the above temperature and coated by high speed kneading while stirring, and the remaining material was dried at the same temperature through an oven to coat the surface of the silicon dioxide filler with stearin.

Next, 100 parts by weight of the first coating material, 100 parts by weight of the second coating material, and 100 parts by weight of the rice husk powder crushed to a 100 mesh size were mixed with 100 parts by weight of the polyethylene resin, And then passed through a cooling bath maintained at 15 캜 to cut into a predetermined size to produce granules.

Subsequently, 0.1 to 0.2 parts by weight of methylene (3,5-ditertiary-butyl-4-hydroxyphenyl) propionate as an antioxidant, 100 parts by weight of tetramethyl-pineridinyl-sebacate 0.1 to 0.2 parts by weight of an ultraviolet light scattering agent, 1 to 2 parts by weight of titanium dioxide as an ultraviolet scattering agent, 0.5 to 3 parts by weight of an alkylaminobenzoate as an insecticide and 0.5 to 3 parts by weight of permethrin as an anti- 85 to 90 wt% were mixed and passed through a sheet extruder to form a sheet, and the sheet thus prepared was wound up to prepare a mulching film.

[Example 2]

Except that 150 parts by weight of the first coating material, 50 parts by weight of the second coating material and 100 parts by weight of the rice husk powder crushed to a 100 mesh size were mixed with 100 parts by weight of the polyethylene resin to prepare granules.

[Example 3]

Example 1 is the same as Example 1 except that 15 to 20 wt% of the synthetic resin base material and 80 to 85 wt% of the granules of Example 1 were mixed.

[Example 4]

Example 2 is the same as Example 2 except that 15 to 20 wt% of the synthetic resin base material and 80 to 85 wt% of the granules of Example 2 were mixed.

[Comparative Example]

Polyethylene (LDPE, Low Density Polyethylene), a commercially available mulching material, was used.

(1) mulching experiment in pepper crop cultivation

The mating films of Example 1 and Comparative Example were used to observe the change with time in the coated state. The results are shown in Table 1 below. In the experiment, pepper was inoculated and mulched in the middle of April, harvested after 5 months of growth period, and the coatings were observed.

Immediately after coating Comparative Example Example 1

As shown in Table 1, the mulching film according to Example 1 of the present invention was spontaneously decomposed during the cultivation period of 5 months, and almost no coating remained. have.

(2) Changes in physical properties depending on the coating period

1 and 2 are graphs showing changes in physical properties during the coating period of the naturally degradable mulching film according to the embodiment of the present invention.

In the experiment, pepper, which is an experimental cultivar, was inoculated and mulched in the middle of April, and pepper was harvested after 5 months of growth period. Examples 1 to 4 were used for the mulching material, and polyethylene (LDPE, Low Density Polyethylene) as a general mulching material was used as a comparative example. The planting intervals were 70cm in the daytime and 20cm in the daytime.

Mechanical properties were measured by using universal test machine (UTM) 4202 from Instron. The mechanical properties such as tensile strength and elongation were measured. The mechanical properties were measured seven times per sample, and the upper and lower limit values were discarded, and the average value was obtained five times.

As shown in Fig. 1, the tensile strength changes with the coating period were steadily decreased after coating in Examples 1 to 4, but in the case of Comparative Examples, there was little change in physical properties.

In the case of Example 1 and Example 2, although the rate of change was similar in the early stage, the rate of change varied with time, and it was confirmed that the cumulative amount of change in Example 1 in which the content of the first coating was high was the greatest. In the case of Examples 1 and 3, it was confirmed that the time required for reducing the tensile strength by half was approximately 1.5 times, and that the rate of change of Example 1 in which the content of the masterbatch was high was the highest.

As shown in FIG. 2, the elongation changes according to the coating period showed a drastic decrease within 50 days after coating in Examples 1 to 4, but thereafter showed a gradual decrease, but in Comparative Examples, there was hardly any change in physical properties . All of the examples showed a rapid decrease within the first 50 days, and then it was confirmed that they converge to similar property values.

1 and 2, a mulching film produced by increasing the weight ratio of the natural degradable master batch to a synthetic resin base material has a shorter period of time required for decomposition. In the case of a mulching film produced by master batches of the same content, It was confirmed that the period of time required for decomposition was different depending on the content of one inorganic filler.

From the experimental results, it can be seen that the spontaneously decomposable mulching film produced by the method according to the present invention is superior to the conventional general mulching film in spontaneous decomposition, and that the decomposition time It is possible to control it.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of the present invention in order to facilitate the understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (5)

A first coating step of coating a surface of the inorganic filler with a biodegradable resin to form a first coating;
A second coating step of coating the surface of the inorganic filler with a photopolymerization agent to form a second coating;
Mixing the first coating and the second coating with a plant fiber powder and a polyolefin resin to form a mixture,
And a granulation step of granulating the mixture. The method according to claim 1,
Wherein the biodegradable resin is at least one selected from starch, polyethylene succinate (PBS), polybutylene-adipate copolymer, polycaprolactone, and polylactic acid. The method according to claim 1,
Wherein the photodegradation is at least one selected from the group consisting of stearin, stearic acid and steroidalolane. Preparing a spontaneous degradable masterbatch prepared by the method according to any one of claims 1 to 3 and a synthetic resin base material for producing a mulching film;
A mixing step of mixing the natural degradable master batch with the synthetic resin base material to form a mixed material,
And a molding step of extruding the mixed material to produce a film. 5. The method of claim 4,
The synthetic resin base material may contain 0.1 to 0.2 parts by weight of an antioxidant, 0.1 to 0.2 parts by weight of an ultraviolet absorber, 1 to 2 parts by weight of an ultraviolet scattering agent, 0.5 to 3 parts by weight of an insect repellent and 0.5 to 3 parts by weight of an anti- ≪ / RTI &
Wherein the base resin is polyethylene or polypropylene.

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