KR101542604B1

KR101542604B1 - Biodegradable film comprising biomass and manufacturing method thereof

Info

Publication number: KR101542604B1
Application number: KR1020150074121A
Authority: KR
Inventors: 김미순
Original assignee: 김미순
Priority date: 2015-05-27
Filing date: 2015-05-27
Publication date: 2015-08-06

Abstract

The present invention relates to a biodegradable film comprising biomass and a manufacturing method thereof and, more specifically, to a biodegradable film comprising biomass with excellent mechanical properties and improved degradation, and to a manufacturing method thereof. The biodegradable film is produced by mixing: a polyethylene resin; a yellow soil; and biomass including starch, rice hulls, wood powder and a glue.

Description

TECHNICAL FIELD [0001] The present invention relates to a biodegradable film containing biomass and a method for producing the biodegradable film,

The present invention relates to a biodegradable film containing biomass and a method for producing the biodegradable film, and more particularly, to a biodegradable film including an environmentally friendly biomass with improved degradability and a method for producing the same.

The Kyoto Protocol, an international convention for the regulation and prevention of global warming, is a transitional agreement made in 1997 to implement the United Nations Framework Convention on Climate Change (UNFCCC) adopted at the Rio International Environment Conference in June 1992, . The official name is 'Kyoto Protocol to the United Nations Framework Convention on Climate Change'.

38 countries, including Australia, Canada, the United States, Japan and the European Union (EU), were adopted by the 3rd Conference of the Parties to the Convention on Climate Change held in Kyoto, Japan in December 1997, On average, greenhouse gases should be cut by 5.2% a year from 2008 to 2012. The Republic of Korea has ratified it in November 2002 and has been classified as a developing country and has not yet fulfilled its legal obligations, but as an OECD member, Mexico is under pressure to cut greenhouse gas emissions.

As the obligatory target countries are concentrated in developing countries from 2013 to 17, it is expected that the Republic of Korea will be required to participate in the enlargement of the target countries to be held from May. According to the statistics of the International Energy Agency (IEA) Was the ninth in the world with 434 million tons in 2000, accounting for 1.8% of the world's total emissions. Moreover, since 1990, since the increase of the emission amounted to 85.4%, it is likely to be classified as an obligatory country because it is the world's highest growth rate.

Material gas in the subject reduction leading to global warming carbon dioxide (CO _2), methane (CH _4), nitrous oxide (NO _2), fluorocarbon (PFC), hydrofluorocarbon (HFC), fluorinated sulfur (SF _6), etc. Bioplastics, which has been applied only to disposable products and some industrialized products, mainly on existing biodegradable plastics, has been used for plants, seaweeds, etc. in recent years as low carbon green growth, global warming, Carbon neutral type It is a very important technological progress because it is rapidly industrialized by expanding to the category of Bio Based Plastics using raw material derived from biomass, .

In order to prevent environmental pollution, a film using biomass has been developed and disclosed in Korean Patent Laid-Open Nos. 10-2015-0012804 and 10-1287034. These films contain biomass including plant powder and the like in a conventional plastic (e.g., polyethylene resin) film. The biodegradability of the film is improved to some extent compared with that of the pure synthetic resin film. However, The mechanical properties are weaker than that of pure synthetic resin. In particular, the use of a synthetic resin as a binder has a limit in improving the degree of decomposition. Accordingly, development of an environmentally friendly film having excellent mechanical properties as pure synthetic resin has been demanded.

Korean Patent Publication No. 10-2015-0012804 Korean Registered Patent No. 10-1287034

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a biodegradable film including biomass including biomass, which has excellent mechanical properties like a conventional pure synthetic resin film, And a method of manufacturing the same.

These and other objects and advantages of the present invention will become apparent from the following description of a preferred embodiment.

The above object can be achieved by a biodegradable film comprising a biomass prepared by mixing a polyethylene resin with a biomass including loess and starch, rice husk, wood powder and glue.

Preferably, the biomass may be from 15 to 25 parts by weight based on 100 parts by weight of the polyethylene resin.

Preferably, the wood flour can be produced by pulverizing at least one of the bark selected from the group consisting of mulberry, paulownia, cedar, whitish, ash, silkworm, real wood, and marbled wood.

Preferably, the biomass may comprise from 20 to 30% by weight of glue for a total of 100% by weight.

The above object can also be accomplished by a method for producing a biomass of the present invention comprising a first step of mixing biomass with starch, rice hull, wood powder and glue, a second step of mixing the polyethylene resin, A third step of melting and then extruding to produce an unstretched film, a fourth step of cooling the unstretched film in a casting drum, a fifth step of uniaxially stretching the cooled unoriented film in the longitudinal direction, A sixth step of biaxially stretching the film in the transverse direction, and a seventh step of heat-treating the biaxially stretched film.

Preferably, in the first step, the wood flour can be produced by using at least one shell selected from the group consisting of mulberry, paulownia, cedar, perilla, ash tree, yarrow, and marbled wood.

Preferably, in the first step, the biomass may comprise 20 to 30% by weight of glue for a total of 100% by weight.

Preferably, in the second step, the biomass may be from 15 to 25 parts by weight based on 100 parts by weight of the polyethylene resin.

According to the present invention, unlike the conventional bio-plastic film, the mechanical properties are improved by containing wood pulverized by crushing a specific bark, and degradability is further improved by using a natural glue as a binder. The mechanical properties similar to those of a pure synthetic resin film And at the same time, the decomposability is improved and environmental pollution can be prevented.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a method for producing a biodegradable film comprising biomass according to one aspect of the present invention. FIG.

Hereinafter, the present invention will be described in detail with reference to examples of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

A biodegradable film comprising a biomass according to an aspect of the present invention is prepared by mixing a polyethylene resin and a biomass including loess and starch, rice hulls, wood flour and glue. Since the biodegradable film composition of the present invention includes biomass, the biodegradable film composition can be easily mixed and the extrusion moldability can be improved by containing loess even though the degradability is improved as compared with a film made only of a conventional synthetic resin (for example, polyethylene resin) And wood powder and glue as a biomass component to have mechanical properties similar to those of existing films.

In one embodiment, the polyethylene resin may be a high density polyethylene (HDPE) resin, a low density polyethylene (LDPE) resin or a mixture thereof. The polyethylene resin is a known polyethylene resin. It is omitted.

In one embodiment, the loess is excellent in viscosity so that the polyethylene resin and biomass can be easily combined. That is, it facilitates the mixing of the biodegradable film composition such as a glue described later, as well as improves the extrusion moldability. The loess is preferably contained in an amount of 5 to 10 parts by weight based on 100 parts by weight of the polyethylene resin. When the content of the loess is less than 5 parts by weight, the viscosity can not be sufficiently obtained and the bond between the biomass and the polyethylene resin can not be completed. When the content is more than 10 parts by weight, the biomass content is relatively decreased, It is uneconomical.

In one embodiment, biomass is a resource of bioenergy, which is a field of new and renewable energy, which means a plant or organism that can be generally used as energy. Biomass has energy-only crops and trees, agricultural and forage crops, agricultural waste and debris, forest waste and debris, aquatic plants and livestock waste, which can be recycled, . Generally, biomass can be classified into two categories: starchy biomass (grains, potatoes, etc.), woody biomass (agricultural byproducts such as wood, herbaceous rice and rice husk), carbohydrate biomass (sugarcane, (Animal carcass, microbial cells, etc.), and the like.

The biomass may include starch, rice hulls, wood powder and glue, and is preferably added in an amount of 15 to 25 parts by weight based on 100 parts by weight of the polyethylene resin. If the content of the biomass is less than 15 parts by weight, the degree of improvement of the decomposability is not sufficient and the biomass content is not satisfied with the object of the present invention. If the content of the biomass exceeds 25 parts by weight, the mechanical properties of the final finished film, This is because.

In one embodiment, starch is one of the starchy biomass, which is excellent in biodegradability, low in cost, rich in resources, and easy to supply. Also, it is free from toxicity and easy to plasticize, and has excellent physical properties like plastic. Starch is plasticized and transformed into thermoplastic starch, so its grain size is acceptable. Potatoes, potatoes, corn, and the like can be produced. From the viewpoint of economy, it is most preferable to use corn, and commercially available ones can be purchased and used.

In one embodiment, the rice husk is one of the woody biomass, which refers to the rough, solid crust of rice. Rice hulls are covered with silicon tightly to the inner and outer shells, so they are not easily corroded. They are used as litter or compost for housing. Recently, they have been used in various fields as biomass. Rice horses are excellent in heat resistance and inexpensive. In addition, the durability is excellent, so that the strength of the final finished product film can be enhanced. As the rice husk, differentiated or undifferentiated rice hulls can be used, and there is no particular limitation with regard to the content, but from the viewpoint of economy, it is preferable to use 50 to 150 parts by weight with respect to 100 weight of the starch.

In one embodiment, wood flour is one of woody biomass, which refers to powder (powder) that has been crushed and ground into bark. When biomass containing only starch and rice hulls is mixed with synthetic resin, it is effective in improving degradability, but mechanical properties such as initial elongation and tensile strength are lowered in film form. Wood flour is added to compensate for these drawbacks, and it is a wood flour which has at least one bark selected from the group consisting of mica, paulownia tree, cedar, timber, ash tree, silkworm, Crushing and grinding. It is preferable to use an ash tree in terms of enduring high temperature in the process of producing the film and enhancing the mechanical properties of the final finished product. The content thereof is preferably 50 to 150 parts by weight based on 100 parts by weight of the starch.

In one embodiment, the glue is a material that solidifies the ore, the intestines, the bones, etc. of the animal and solidifies the liquid, and binds the starch, rice husks and wood flour, and acts as a binder to bind the polyethylene resin and the biomass. Conventionally, a film containing biomass has been made of synthetic resins such as linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and high density polyethylene (HDPE) as binders (Korean Patent Publication No. 10-2015-0012804 and Korean Registered Patent See Publication No. 10-1287034). They cause the mixed composition to bind well as a binder, but it degrades the degradability of the final product, the film, as a synthetic resin. However, in the case of glue, the object of the present invention can be achieved by improving the degradability of the film, which is a final product, while ensuring good adhesion between the synthetic resin and the biomass. The glue is preferably contained in an amount of 20 to 30% by weight based on 100% by weight of the whole biomass including starch, rice husks and wood flour. If the content of the glue is less than 20% by weight, the polyethylene resin and the biomass can not be adequately entangled so that the extrusion is restricted in the form of a film. When the content exceeds 30% by weight, the content of biomass such as starch, And the mechanical properties of the final finished product film are deteriorated.

In addition, various additives may be further added to improve the performance, workability and the like of the product within the scope of the present invention. For example, it is possible to add an oxidizing agent for accelerating the decomposition of the polyethylene resin and accelerating thermal decomposition and photodegradation, a wax for enhancing the water resistance by coating the biomass, and the like as a plasticizer, a lubricant, a compatibilizing agent and an inorganic filler Can be added.

According to another aspect of the present invention, there is provided a method for producing a biodegradable film comprising biomass, comprising the steps of: preparing biomass by mixing starch, rice hulls, wood powder and glue; mixing the polyethylene resin, A third step of melting the masterbatch at 180-220 占 폚 and extruding to produce an unstretched film; a fourth step of cooling the unstretched film in a casting drum; a fourth step of cooling the unstretched film; A fifth step of uniaxially stretching in the longitudinal direction, a sixth step of biaxially stretching the uniaxially stretched film in the width direction, and a seventh step of heat treating the biaxially stretched film (see Fig. 1).

In one embodiment, the first step is the step of producing the biomass, wherein the biomass is prepared by mixing starch, rice husks and wood flour and adding glue as a binder. Starch, rice husks, wood flour, glue have been described above, so overlapping parts are omitted. An oxidizer, a wax, a plasticizer, and the like may be further added to improve the physical properties and degradability of the final finished product of the biomass.

In one embodiment, the second step is to mix the polyethylene resin with the loess and biomass to prepare a master batch. When the polyethylene resin, the yellow loess, and the biomass are directly injected into the extruder to produce a film, the constituent components do not mix well and the state of the finished film is not uniform, and the film molding machine is stopped due to the powder Can cause. Therefore, it is preferable to mix the polyethylene resin, the yellow loess and the biomass to prepare a master batch, and then introduce the master batch into the extruder. In this case, the biomass is preferably added in an amount of 15 to 25 parts by weight based on 100 parts by weight of the polyethylene resin, and the loess is preferably included in 5 to 10 parts by weight with respect to 100 parts by weight of the polyethylene resin. If the content of the biomass is less than 15 parts by weight, the degree of improvement of the decomposability is not sufficient and the biomass content is not satisfied with the object of the present invention. If the content of the biomass exceeds 25 parts by weight, the mechanical properties of the final finished film, This is because. When the content of the loess is less than 5 parts by weight, the viscosity can not be sufficiently obtained and the bond between the biomass and the polyethylene resin can not be made perfect. When the content is more than 10 parts by weight, the biomass content is relatively decreased, Falling, and uneconomical.

In one embodiment, the third step is to melt the masterbatch at 180-220 < 0 > C and then extrude to produce an unoriented film.

In one embodiment, the fourth step is a step of cooling the unstretched film in a casting drum.

In one embodiment, the fifth step is a step of uniaxially stretching the cooled unoriented film in the longitudinal direction to produce a uniaxially stretched film. The cooled unoriented sheet is heated by heating means such as roll heating and infrared heating (Heater), and is first stretched in the longitudinal direction to obtain a uniaxial film. Preferably, the stretching is carried out using the main speed difference of two or more rolls, and the stretching temperature is set to a temperature not lower than the glass transition temperature (Tg) of the polyethylene resin and the stretching magnification is 3.0 to 5.0 times.

In one embodiment, the sixth step is a step of biaxially stretching the uniaxially stretched film in the transverse direction to produce a biaxially stretched film, wherein the uniaxially stretched film is continuously stretched in a direction perpendicular to the longitudinal direction , &Quot; width direction "). In this case, the transverse direction stretching is carried out while raising the temperature from a temperature higher than the glass transition temperature (Tg) of the polyethylene resin to a temperature higher than the glass transition temperature (Tg) by 5 to 70 ° C, and a stretching magnification of 3.0 to 5.0 times desirable. The temperature rise in the widthwise stretching process may be continuous or may be stepwise (sequential), but the temperature is usually increased sequentially. For example, the width direction stretching zone of the tenter is divided into plural pieces along the film running direction, and the temperature is raised by flowing a heating medium at a predetermined temperature for each zone.

In one embodiment, the seventh step is a step of heat-treating the biaxially stretched film. That is, the biaxially stretched film is successively subjected to heat treatment such as heat fixation or heat relaxation while running the biaxially stretched film to produce a biaxially oriented film. Thus, in order to complete the crystal orientation of the obtained biaxial oriented film and to impart planarity and dimensional stability, heat treatment is performed in the tenter at a temperature of 150 to 250 DEG C for 1 to 30 seconds. Heat treatment Next, the mixture is uniformly cooled, and then cooled to room temperature to obtain a biodegradable film containing the biomass as a final product. At this time, during the heat treatment step, a relaxation treatment of 3 to 12% in the width direction or the longitudinal direction may be carried out if necessary.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Production Example 1]

100 parts by weight of starch (200 parts by weight), 100 parts by weight of starch (Qiwon corn starch, Samyang Genex Co., Ltd.), 100 parts by weight of rice husk (Citi farm) and 100 parts by weight of ground wood shavings were added to a high- Phoenix, Japan) was added to prepare a biomass having a glue content of 14%.

[Production Example 2]

A biomass having a glue content of 20% was prepared in the same manner as in Preparation Example 1, except that 75 parts by weight of glue was added.

[Production Example 3]

A biomass having a glue content of 25% was prepared in the same manner as in Preparation Example 1, except that 100 parts by weight of glue was added.

[Production Example 4]

A biomass having a glue content of 30% was prepared in the same manner as in Preparation Example 1, except that 128 parts by weight of glue was added.

[Production Example 5]

A biomass having a glue content of 36% was prepared in the same manner as in Preparation Example 1, except that 170 parts by weight of glue was added.

[Production Example 6]

Biomass was prepared in the same manner as in Production Example 1, except that 100 parts by weight of linear low density polyethylene (LLDPE) was added instead of glue.

The components of the biomass prepared according to Preparation Examples 1 to 6 are summarized in Table 1 below.

[Example 1]

100 parts by weight of polyethylene resin and 7 parts by weight of loess and 20 parts by weight of biomass prepared in Preparation Example 2 were mixed and master batches were prepared using a twin screw extruder. The mixture was put into a film forming machine and melted at 200 ° C, Film type.

[Example 2]

100 parts by weight of polyethylene resin and 7 parts by weight of loess and 20 parts by weight of biomass prepared by Preparation Example 3 were mixed and master batches were prepared by using a twin screw extruder. The master batches were put into a film forming machine and melted at 200 DEG C, Film type.

[Example 3]

100 parts by weight of polyethylene resin, 7 parts by weight of yellow loam and 20 parts by weight of biomass prepared in Production Example 4 were mixed and master batches were prepared by using a twin screw extruder. The master batches were put into a film forming machine and melted at 200 ° C, Film type.

[Example 4]

100 parts by weight of polyethylene resin and 7 parts by weight of loess and 20 parts by weight of biomass prepared in Preparation Example 2 were mixed and master batches were prepared using a twin screw extruder. The mixture was put into a film forming machine and melted at 200 ° C, An unoriented film was produced. Subsequently, the unstretched film was cooled and solidified in a casting drum having a surface temperature of 20 캜, heated to 3.0 times in the longitudinal direction, and then cooled. Subsequently, the uniaxially stretched film in the longitudinal direction was led to a tenter while holding both ends thereof with clips, and stretched at 3.5 times in the direction perpendicular to the length (width direction) in the heated atmosphere.

Thereafter, heat setting was carried out at 230 DEG C in a tenter, and the film was cooled to room temperature to prepare a biaxially stretched film.

[Example 5]

And 20 parts by weight of the biomass prepared in Production Example 3 were mixed to prepare a masterbatch. Thus, a biaxially stretched film was prepared in the same manner as in Example 4.

[Example 6]

And 20 parts by weight of the biomass prepared in Production Example 4 were mixed to prepare a masterbatch. Thus, a biaxially stretched film was produced in the same manner as in Example 4.

[Comparative Example 1]

100 parts by weight of the polyethylene resin and 20 parts by weight of the biomass prepared in Preparation Example 6 were mixed and then master batches were prepared using a twin screw extruder. The master batches were put into a film molding machine and melted at 200 ° C, Respectively.

[Comparative Example 2]

100 parts by weight of the polyethylene resin and 20 parts by weight of the biomass prepared in Preparation Example 1 were mixed and master batches were prepared using a twin screw extruder. The master batches were put into a film molding machine and melted at 200 ° C, Respectively.

[Comparative Example 3]

100 parts by weight of the polyethylene resin and 20 parts by weight of the biomass prepared in Preparation Example 5 were mixed and then master batches were prepared using a twin-screw extruder. The master batches were put into a film molding machine and melted at 200 DEG C, Respectively.

The constituent components of the examples and comparative examples and whether or not they were drawn are summarized in Table 2.

[Experimental Example 1: Extrusion productivity evaluation]

Examples 1 to 6 and Comparative Examples 1 to 3 were extruded into thin films (10 mu m) to evaluate the productivity, and the results are shown in Table 3 below. In the case of "? &Quot;, it can be extruded into a thin film (10 m) in the case of "DELTA" , It means that the extrusion is restricted to a thin film (10 mu m) and the productivity is deteriorated.

As can be seen from Tables 1 to 3, in the case where the content of glue as a binder is small, that is, 14% with respect to the total weight of biomass, and Comparative Example 2 which does not contain yellow clay, In Comparative Example 1 or 3, which does not contain yellow loess, the productivity was slightly inferior to that in Examples. All of the examples showed excellent productivity. This seems to be due to the fact that the biomass is not mixed smoothly and is not strongly bound to the polyethylene resin when the content of the binder, glue, is low or does not contain yellow clay.

[Experimental Example 2: Evaluation of mechanical properties]

Tensile strength and elongation were evaluated for Examples 1 to 6 and Comparative Examples 1 to 3 (ASTM D 3826). All of Examples 1 to 6 had excellent tensile strength and elongation. However, in the comparative example, the tensile strength and elongation were insufficient. (Comparative Examples 1 to 3), the amount of glue as a binder was small and the biomass and the polyethylene resin were not mixed well (Comparative Example 2), and the amount of glue was increased so that the amount of starch, (Comparative Example 3). It was also confirmed that biaxially stretched Examples 4 to 6 had much better tensile strength and elongation than the other Examples and Comparative Examples.

[Experimental Example 3: Evaluation of photodegradability]

Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to photodegradability evaluation (ASTM D15). The film was irradiated with ultraviolet rays for 200 hours using a QUV Accelerated Weathering Tester, and the film was measured for tensile strength and elongation at a rate of 0.5 w / nf (310). In Examples 1 to 6 and Comparative Examples 2 and 3, the tensile strength and elongation retention ratio sharply decreased to about 5%, but decreased to only about 20% in Comparative Example 1. This seems to be due to the use of synthetic resin rather than glue as a binder.

Through various experiments on the examples and comparative examples, it was found that unlike the conventional biomass-containing film, wood powder was added, glue was used as a binder, and loess was added to facilitate mixing. But also degradability is improved, which is suitable for use as an eco-friendly film.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

In a biodegradable film comprising biomass,
Polyethylene resin;
ocher; And
Starch, rice husks, wood flour, and glue;
The wood flour is prepared by pulverizing the ash shell,
5 to 10 parts by weight of the loess is contained with respect to 100 parts by weight of the polyethylene resin, 15 to 25 parts by weight of the biomass is contained,
Wherein the biomass comprises 20 to 30 wt% of the glue relative to 100 wt% of the total biodegradable film.

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A biodegradable film production method comprising the steps of:
A first step of preparing biomass by mixing starch, rice husks, wood flour and glue;
A second step of mixing the polyethylene resin with the loess and the biomass to prepare a master batch; And
A third step of melting the master batch at 180 to 220 캜 and extruding the master batch to produce an unstretched film;
A fourth step of cooling the unstretched film in a casting drum;
A fifth step of uniaxially stretching the cooled unoriented film in the longitudinal direction;
A sixth step of biaxially stretching the uniaxially stretched film in the width direction;
And a seventh step of heat-treating the biaxially stretched film,
The wood flour is prepared by pulverizing the ash shell,
5 to 10 parts by weight of the loess is contained with respect to 100 parts by weight of the polyethylene resin, 15 to 25 parts by weight of the biomass is contained,
Wherein the biomass comprises 20 to 30% by weight of the glue relative to 100% by weight of the total biomass.

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