KR20230079933A - Method for manufacturing biogradable film and biogradable film manufactured by the same - Google Patents

Abstract

The present invention relates to a method for producing a biodegradable film that does not require a separate solvent other than an aqueous solvent, is biodegradable, is environmentally friendly, and has excellent mechanical properties such as shrinkage, tensile strength, and elongation, and a biodegradable film produced thereby.

Description

Method for manufacturing a biodegradable film and a biodegradable film produced thereby

The present invention relates to a method for producing a biodegradable film and a biodegradable film produced thereby.

Conventional bio-regenerated cellulose, which uses eco-friendly materials as raw materials, has undergone a chemical treatment process, and various efforts have been made to minimize the impact on air pollution and environmental pollution.

Toxic substances generated during the production of cellulose sodium xanthate used in the existing viscose process and regeneration from aqueous sulfuric acid solution cause environmental pollution and are not suitable for the human body. This can occur and cause water pollution.

Therefore, in recent years, various efforts have been made in the industry to manufacture bio-cellulose using environmentally friendly solvents when dissolved or recoverable solvents such as acetone and ethanol, and there is a need for a technology that can expand the production scale by adjusting these processes.

In addition, the environmentally friendly material used as a raw material for melting is an environmentally friendly material based on cellulose, and cotton, wood pulp, and the like are used. In particular, bamboo is hollow and composed of nodes, and is one of the plants with the fastest growth rate among plants, and is considered as a raw material for pulp used in manufacturing biodegradable films.

The technical problem to be achieved by the present invention is to provide a method for producing a biodegradable film that does not require a separate solvent other than an aqueous solvent in the process of forming, coagulating and regenerating a bamboo-based cellulose lysate and providing a biodegradable film produced thereby is to do

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An exemplary embodiment of the present invention comprises the steps of forming bamboo pulp by reacting a bamboo raw material with a mixed solvent of a glycol ether-based solvent and an acid; mixing the bamboo pulp with a basic compound to prepare a bamboo pulp slurry; homogenizing the bamboo pulp slurry to prepare a solution product; And preparing a biodegradable film using the solvate; including, preparing the biodegradable film; provides a method for producing a biodegradable film using an aqueous solvent of pH 5 or more and 8 or less. .

In addition, one embodiment of the present invention provides a biodegradable film prepared by the above manufacturing method.

Since the method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention does not require a separate solvent other than an aqueous solvent, it is possible to manufacture a biodegradable film in an eco-friendly and efficient manner.

In addition, the method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention can provide a biodegradable film that is biodegradable and environmentally friendly, and has excellent mechanical properties such as shrinkage, tensile strength and elongation.

In addition, the biodegradable film according to an exemplary embodiment of the present invention may have excellent mechanical properties such as shrinkage, tensile strength and elongation.

However, the effects of the present invention are not limited to the above-described effects, and may be variously extended within a range that does not deviate from the spirit and scope of the present invention.

Throughout the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Throughout the present specification, when a member is said to be located “on” another member, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members.

Throughout the present specification, the unit "parts by weight" may mean the ratio of the weight of each component.

Hereinafter, the present invention will be described in more detail.

An exemplary embodiment of the present invention comprises the steps of forming bamboo pulp by reacting a bamboo raw material with a mixed solvent of a glycol ether-based solvent and an acid; mixing the bamboo pulp with a basic compound to prepare a bamboo pulp slurry; Homogenizing the pulp slurry to prepare a solution product; And preparing a biodegradable film using the solvate; including, preparing the biodegradable film; provides a method for producing a biodegradable film using an aqueous solvent of pH 5 or more and 8 or less. .

The method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention is biodegradable and environmentally friendly, and can stably manufacture a biodegradable film having excellent mechanical properties such as shrinkage, tensile strength and elongation. In addition, since the method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention does not require a separate solvent other than an aqueous solvent, it is possible to manufacture a biodegradable film in an eco-friendly and efficient manner. In addition, the method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention can manufacture a biodegradable film at low cost, so it can be more economical than conventional processes that require a separate solvent.

Hereinafter, each step of the manufacturing method will be described in detail.

According to an exemplary embodiment of the present invention, first, bamboo pulp may be formed by reacting a bamboo raw material with a mixed solvent of a glycol ether solvent and an acid. In forming the bamboo pulp, a mixed solvent may be first prepared by mixing a glycol ether-based solvent and an acid, and bamboo raw materials may be added to the mixed solvent to prepare bamboo pulp.

According to an exemplary embodiment of the present invention, the bamboo raw material may include at least one of kingdae, songdae, and a mixture thereof. Specifically, the bamboo raw material may include bamboo chips of at least one of king bamboo, song bamboo, and a mixture thereof, but the type of the bamboo raw material is not limited. By using the above-described kind of bamboo raw material, the biodegradable film having high biodegradability and being an environmentally friendly material can be manufactured.

According to an exemplary embodiment of the present invention, organic solvent pulp may be prepared using the bamboo raw material. Specifically, bamboo pulp may be formed by reacting the bamboo raw material with a mixed solvent of a glycol ether solvent and an acid. When pulp is formed by reacting bamboo raw materials with a mixed solvent of glycol ether solvent and acid, as described below, the amount of bamboo pulp included in the bamboo pulp slurry during alkali homogenization, the amount of bamboo pulp slurry introduced into the homogenizer, etc. By adjusting, it is possible to easily adjust the physical properties of the biodegradable film produced. On the other hand, if conventional kraft pulp, sulfite pulp, etc. are used, it may be difficult to easily control the physical properties of the biodegradable film produced even when alkali homogenization conditions are adjusted.

According to an exemplary embodiment of the present invention, the mixed solvent may be a mixture of a glycol ether-based solvent and an acid. The glycol ether-based solvent is ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and dipropylene glycol methyl ether. However, the type of the glycol ether-based solvent is not limited. In addition, hydrochloric acid, sulfuric acid, nitric acid and the like can be used as the acid. For example, the acid may be sulfuric acid, but the type of acid is not limited.

According to an exemplary embodiment of the present invention, the glycol ether-based solvent may serve as a cross-linking compound between lignin-containing cellulose-based fine fibers derived from the bamboo pulp, and as a result improve mechanical properties of the biodegradable film produced it could be

According to an exemplary embodiment of the present invention, the content of the glycol ether-based solvent may be 90 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of the mixed solvent. Specifically, the content of the glycol ether-based solvent is 90 parts by weight or more and 100 parts by weight or less, 90 parts by weight or more and 98 parts by weight or less, 90 parts by weight or more and 96 parts by weight or less, 90 parts by weight based on 100 parts by weight of the mixed solvent. 94 parts by weight or less, 92 parts by weight or more and 100 parts by weight or less, 94 parts by weight or more and 100 parts by weight or less, 96 parts by weight or more and 100 parts by weight or less, 92 parts by weight or more and 98 parts by weight or less, 94 parts by weight or more and 98 parts by weight or less can When the content of the glycol ether-based solvent is within the above range, it may be suitable for preparing bamboo pulp soluble in basic compounds.

According to an exemplary embodiment of the present invention, the molar concentration of the acid contained in the mixed solvent may be 0.5 M or more and 2.0 M or less. Specifically, the molarity of the acid contained in the mixed solvent is 0.5 M or more and 1.8 M or less, 0.5 M or more and 1.6 M or less, 0.5 M or more and 1.4 M or less, 0.5 M or more and 1.2 M or less, 0.5 M or more and 1.0 M or less, 0.7 M or more. M or more, 2.0 M or less, 0.9 M or more, 2.0 M or less, 0.9 M or more, 2.0 M or less, 1.1 M or more, 2.0 M or less, 1.3 M or more, 2.0 M or less, 1.5 M or more, 2.0 M or less, 0.7 M or more, 1.8 M or less, or 0.9 M It may be more than 1.6 M or less. When the molar concentration of the acid contained in the mixed solvent is within the above range, bamboo pulp can be easily separated through hydrolysis of the bamboo raw material.

According to an exemplary embodiment of the present invention, the volume ratio of the glycol ether-based solvent and the acid contained in the mixed solvent may be 88:12 or more and 98:2 or less. Specifically, the volume ratio of the glycol ether-based solvent and the acid contained in the mixed solvent is 90:10 or more, 98:2 or less, 92:8 or more, 98:2 or less, 94:6 or more, 98:2 or less, 95:5 98:2 or less, 88:12 or more 97:3 or less, 88:12 or more 96:4 or less, 88:12 or more 95:5 or less, 88:12 or more 90:10 or less, or 90:10 or more 95:5 or less can For example, the volume ratio of the glycol ether-based solvent and the acid may be 97.3:2.7. When the volume ratio of the glycol ether-based solvent and the acid contained in the mixed solvent is within the above-described range, bamboo pulp suitable for preparing a bamboo pulp slurry and solution product can be effectively prepared from the bamboo raw material.

According to an exemplary embodiment of the present invention, the step of forming the bamboo pulp may include reacting the mixed solvent at a mixing ratio of 100 g or more and 500 g or less with respect to 100 g of the bamboo raw material. Specifically, the mixing ratio of the mixed solvent to 100 g of the bamboo raw material may be 100 g or more and 400 g or less, or 300 g or less. By adjusting the mixing ratio of the bamboo raw material and the mixed solvent within the above-described range, bamboo pulp suitable for preparing a bamboo pulp slurry and solution product may be more easily formed.

According to one embodiment of the present invention, the weight ratio of the bamboo raw material and the mixed solvent may be 1:1 or more and 1:5 or less. Specifically, the weight ratio of the bamboo raw material and the mixed solvent is 1:1 or more and 1:4 or less, 1:1 or more and 1:3 or less, 1:2 or more and 1:5 or less, or 1:3 or more and 1:5 or less can By controlling the weight ratio of the bamboo raw material and the mixed solvent within the above-described range, bamboo pulp suitable for preparing a bamboo pulp slurry and solution product may be more easily formed.

According to an exemplary embodiment of the present invention, the step of forming the bamboo pulp may be performed at a temperature of 100 °C or more and 150 °C or less. Specifically, the temperature in the step of forming the bamboo pulp may be 110 °C or higher and 140 °C or lower, or 120 °C or higher and 130 °C or lower. The bamboo pulp may be stably formed from the bamboo raw material by adjusting the temperature at which the step of forming the bamboo pulp is performed within the above range.

In addition, the step of forming the bamboo pulp may be performed for 30 minutes or more and 120 minutes or less, 60 minutes or more and 120 minutes or less, or 30 minutes or more and 60 minutes or less. When the time for performing the step of forming the bamboo pulp is within the above range, the bamboo pulp may be stably formed and the yield of the bamboo pulp may be improved.

According to one embodiment of the present invention, the prepared bamboo pulp may be washed. Specifically, distilled water may be used to remove unpulped reactants and residual mixed solvents. Through this, impurities contained in the pulp can be minimized, and alkali homogenization treatment described later can be effectively performed.

According to an exemplary embodiment of the present invention, a bamboo pulp slurry may be prepared by mixing the prepared bamboo pulp with a basic compound. The basic compound may be added in the form of a basic solution, and the basic solution may include a sodium hydroxide solution, a potassium hydroxide solution, and a lithium hydroxide solution, but the type of the basic solution is not limited.

According to an exemplary embodiment of the present invention, the concentration of the basic solution may be 0.1 N to 1 N. Specifically, the concentration of the basic solution may be 0.15 N to 0.8 N, 0.2 N to 0.6 N, or 0.25 N to 0.5 N. When the concentration of the basic solution is within the above-described range, it may be easy to prepare a bamboo pulp slurry having a bamboo raw material content within the specific range.

According to an exemplary embodiment of the present invention, the amount of the basic compound may be 5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the solution cargo. Specifically, the amount of the basic compound is 5 parts by weight or more and 9 parts by weight or less, 5 parts by weight or more and 7 parts by weight or less, 7 parts by weight or more and 10 parts by weight or less, or 7 parts by weight or more 9 parts by weight or more based on 100 parts by weight of the solution. It may be less than parts by weight. When the content of the basic compound is within the above-described range, a solution product can be effectively formed from the bamboo pulp slurry through homogenization, freezing, and dissolution as described below, and the solution product is prepared from an aqueous solvent having a pH of 5 or more and 8 or less. It may be suitable for effectively forming a biodegradable film.

According to an exemplary embodiment of the present invention, the dissolution rate of the bamboo pulp in the solution product may be 50% or more and 100% or less. Specifically, the dissolution rate of the bamboo pulp in the solution cargo is 50% or more and 90% or less, 50% or more and 80% or less, 60% or more and 100% or less, 70% or more and 100% or less, 80% or more and 100% or less, 60 % or more and 90% or less or 70% or more and 80% or less. “Dissolution rate” refers to preparing a bamboo pulp slurry using a certain amount (W 0 ) of the bamboo pulp, homogenizing, freezing and dissolving as described below to obtain a solution product, and then centrifuging it to remove solid content (W _s ) And when a cellulose solution is obtained, it can be calculated by the following formula 1. The W ₀ and W _s may be units of mass.

[Equation 1]

Dissolution rate (%) = 100 * (W ₀ -W _s )/W ₀

When the dissolution rate of the bamboo pulp in the solution is within the above range, a biodegradable film may be stably formed from the solution.

According to an exemplary embodiment of the present invention, the solid content may be lignin-containing cellulose-based microfibers, and the lignin-containing cellulose-based microfibers may swell in the dissolution process and exist in micro units. For example, the size of the lignin-containing cellulose-based microfibers may be 0.1 μm or more and 500 μm or less.

According to one embodiment of the present invention, the content of the bamboo pulp may be 5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the solution cargo. Specifically, the content of the bamboo pulp is 5 parts by weight or more and 9 parts by weight or less, 5 parts by weight or more and 7 parts by weight or less, 7 parts by weight or more and 10 parts by weight or less, or 7 parts by weight or more 9 parts by weight or less, based on 100 parts by weight of the solution. It may be less than parts by weight.

By adjusting the content of the bamboo pulp included in the solution product within the above-described range, friction and dispersion between fibers are efficiently performed during the homogenization process using the homogenizer, so that the solution product can be easily prepared. On the other hand, if the content of the bamboo pulp included in the solution product is too small, the efficiency of friction between fibers is lowered, making it impossible to easily prepare the solution product. In addition, when the content of the bamboo pulp included in the liquefied product is too large, the liquefied product has a high viscosity and does not smoothly react with the basic compound.

Therefore, in the method for manufacturing a biodegradable film according to an exemplary embodiment of the present invention, by adjusting the content of the bamboo pulp within the above range, the viscosity of the solution may be suitable for forming a biodegradable film, and the biodegradable product produced Mechanical properties such as shrinkage, tensile strength and elongation of the film can be easily controlled.

Next, a solution product may be prepared by homogenizing the bamboo pulp slurry.

According to an exemplary embodiment of the present invention, the homogenizing step may be performed at a rotational speed of 1000 rpm or more and 5000 rpm or less. Specifically, the rotation speed at which the homogenizing step is performed is 1500 rpm or more and 5000 rpm or less, 2000 rpm or more and 5000 rpm or less, 2500 rpm or more and 5000 rpm or less, 3000 rpm or more and 4000 rpm or less, 1000 rpm or more and 4000 rpm or less, 1000 rpm It may be 3000 rpm or less or 2000 rpm or more and 4000 rpm or less. By adjusting the rotational speed at which the homogenizing step is performed within the above range, the prepared bamboo pulp slurry can be formed more stably. The rotational speed may refer to the rotational speed of a homogenizer used in the homogenization step.

According to one embodiment of the present invention, the homogenizing step may be performed at a temperature of 20 ° C. or more and 35 ° C. or less. By controlling the temperature in the step of performing the homogenization within the above range, it is possible to suppress deformation and damage of the lignin-containing cellulose-based fine fibers included in the prepared solution.

According to an exemplary embodiment of the present invention, the method for producing the biodegradable film may control the physical properties of the biodegradable film to be produced by adjusting the time for performing the homogenization. Specifically, the step of performing the homogenization may be performed for a time of 1 minute or more and 1 hour or less. Through this, it is possible to effectively control a biodegradable film that satisfies mechanical properties such as shrinkage, tensile strength and elongation of the biodegradable film produced. On the other hand, the time for performing the homogenization may be set according to the desired physical properties of the biodegradable film.

According to an exemplary embodiment of the present invention, the step of homogenizing the bamboo pulp slurry may be preparing a solution containing lignin-containing cellulose-based fine fibers. Specifically, a solution containing lignin-containing cellulose-based fine fibers may be prepared by homogenizing the above-described bamboo pulp slurry. Through this, cellulose nanofibrils (CNF) or microfibrillated cellulose (MFC) can be prepared. In order to homogenize the bamboo pulp slurry, a high-pressure homogenizer or a high-pressure emulsifier used in the art may be used. For example, when the bamboo pulp slurry is homogenized using a high-pressure homogenizer, the number of passages of the bamboo pulp slurry through the high-pressure homogenizer, the operating pressure of the high-pressure homogenizer, etc. are adjusted to obtain lignin-containing solution. The size, shape, etc. of the cellulose-based fine fibers can be controlled.

According to an exemplary embodiment of the present invention, the lignin content of the lignin-containing cellulose-based fine fibers may be 30% by weight or less. That is, the lignin content of the lignin-containing cellulose-based fine fibers prepared from the bamboo pulp slurry may be 30% by weight or less, and the lignin content of the lignin-containing cellulose-based fine fibers prepared from the bamboo pulp slurry may be 30% by weight or less there is. Specifically, the lignin content of the prepared lignin-containing cellulose-based fine fibers is 0.1% by weight or more and 30% by weight or less, 1% by weight or more and 28% by weight or less, 5% by weight or more and 25% by weight or less, 10% by weight or more 22.5% by weight or less, or 15% by weight or more and 20% by weight or less. On the other hand, by removing the lignin by bleaching the prepared lignin-containing cellulose-based fine fibers, it is possible to form cellulose-based fine fibers having a lignin content of 0% by weight.

When the lignin content of the lignin-containing cellulose-based fine fibers is within the above range, mechanical properties such as shrinkage, tensile strength and elongation of the biodegradable film produced can be effectively improved.

According to one embodiment of the present invention, the size of the lignin-containing cellulose-based fine fibers may be 0.1 μm or more and 500 μm or less. Specifically, the size of the lignin-containing cellulose-based fine fibers prepared from the bamboo pulp slurry may be 0.1 μm or more and 500 μm or less. Specifically, the size of the lignin-containing cellulose-based fine fibers is 1 μm or more and 475 μm or less, 5 μm or more and 450 μm or less, 10 μm or more and 400 μm or less, 20 μm or more and 375 μm or less, 30 μm or more and 350 μm or less, 40 μm. 320 μm or less, 0.1 μm or more and 100 μm or less, 10 μm or more and 100 μm or less, 15 μm or more and 97.5 μm or less, 20 μm or more and 95 μm or less, or 25 μm or more and 92.5 μm or less. When the size of the lignin-containing cellulose-based fine fibers is within the above range, mechanical properties such as shrinkage, tensile strength and elongation of the biodegradable film can be effectively improved. In addition, the size of the lignin-containing cellulose-based fine fibers may mean the average size of the particles.

According to an exemplary embodiment of the present invention, the lignin-containing cellulose-based fine fibers may be partially present in an undissolved form in the solution product, and may exist partially dissolved in the solution product. By the dissolution, when separated into small-sized pieces containing several monomers, it may exist in a dissolved form in the solution cargo, and when it contains several dozen or more monomers and is separated into large-sized pieces, it is a solution cargo in undissolved form. may exist in dispersed form.

According to an exemplary embodiment of the present invention, preparing the solution cargo; may further include freezing and dissolving the homogenized bamboo pulp slurry. Specifically, the freezing may be performed by freezing the homogenized bamboo pulp slurry at a temperature of -20 ° C or lower, and the melting may be performed by reacting the basic compound with the bamboo pulp dispersed in the homogenized bamboo pulp slurry. there is. More specifically, in the solution product obtained by dissolving after freezing as described above, the dissolution of lignin-containing cellulose-based fine fibers is achieved by the difference in thermal energy during the freezing and dissolution process, and the solution product gradually changes from the form of a dispersion containing fibers to fibers. As the dissolution progresses, the fiber swells and becomes micronized, and the dissolution rate may increase.

According to an exemplary embodiment of the present invention, the freezing is -20 ℃ or less, -50 ℃ or more -20 ℃ or less, -40 ℃ or more -20 ℃ or less, -30 ℃ or more -20 ℃ or less, -50 ℃ or more - It may be performed at a temperature of 25 ° C or less, -40 ° C or more -25 ° C or less, -30 ° C or more -25 ° C or less, -50 ° C or more -30 ° C or less, or -40 ° C or more -30 ° C or less. When freezing is performed at a temperature within the above range, the bamboo pulp may be easily dissolved.

According to one embodiment of the present invention, the freezing time may be adjusted according to the freezing temperature. That is, the freezing may be performed until the bamboo pulp slurry is completely frozen, or may be performed for a relatively short time when the freezing temperature is low.

According to an exemplary embodiment of the present invention, the homogenization, freezing and dissolution processes may be performed 1 to 10 times, for example, 3 times. When the above homogenization, freezing, and dissolution processes are repeatedly performed, the dissolution rate can be increased because a portion of the remaining bamboo pulp is dissolved and the remaining bamboo pulp can be further dissolved, and a solution having a dissolution rate suitable for production of a biodegradable film is easily obtained. can do.

According to one embodiment of the present invention, the prepared bamboo pulp may be washed. Specifically, impurities contained in the bamboo pulp may be removed using distilled water. Through this, it is possible to effectively prevent degradation of the physical properties of the biodegradable film produced.

According to an exemplary embodiment of the present invention, preparing the biodegradable film; casting and drying the solution into a film shape; and introducing the dried solvate into a batch containing the aqueous solvent.

Specifically, preparing the biodegradable film; may include casting and drying the solution in a film shape; obtaining the solution and then drying it as it is to prepare a biodegradable film. it could be

In the case of the biodegradable film prepared in this way, the solids derived from the lignin-containing lignin-containing cellulose-based fine fibers in the solution are contained as they are, and thus the transparency may be somewhat low, but the solids serve as a supplement for the film, resulting in a biodegradable film The mechanical properties of may be excellent.

According to an exemplary embodiment of the present invention, preparing a biodegradable film using the solvate; is centrifuging the solvate to remove solids and obtaining a cellulose solution; and drying the cellulose solution into a film shape.

According to an exemplary embodiment of the present invention, a cellulose solution may be obtained by removing solids contained in the solution. That is, the cellulose solution may be in a state including dissolved lignin-containing cellulose-based fine fibers, a mixed solvent of a glycol ether-based solvent and an acid, and a basic compound.

According to one embodiment of the present invention, when the biodegradable film is used as an important material for durability, such as food packaging for distribution, it can be used as a biodegradable film prepared by using the solution as it is, such as food wrap or sanitary vinyl. When transparency is important for one-time use, a biodegradable film prepared by removing the solid content of the solution product can be utilized.

According to an exemplary embodiment of the present invention, the film shape may be formed by casting a solution product or a cellulose solution into a film shape. Specifically, a biodegradable film may be prepared by pouring the solvate or cellulose solution into a plate-shaped mold such as a Petri dish and then drying it.

According to an exemplary embodiment of the present invention, the drying may be performed by creating a vacuum environment at a temperature of 50 °C or higher. Specifically, it may be to remove moisture from the solution or cellulose solution using a vacuum dryer or the like used in the art. When the drying is performed at a temperature and method within the aforementioned range, a biodegradable film may be obtained more rapidly.

According to an exemplary embodiment of the present invention, the step of preparing the biodegradable film; may further include the step of introducing the dried solvate into a batch containing the aqueous solvent. Specifically, after the step of preparing the biodegradable film, the step of treating the dried solvate using an aqueous solvent and further drying it; may be further included. That is, since the above process does not require a separate solvent such as an aqueous solution of sulfuric acid in addition to the aqueous solvent, it is possible to manufacture a biodegradable film more economically by minimizing chemicals used in the entire process.

According to an exemplary embodiment of the present invention, preparing the biodegradable film; may be to use an aqueous solvent of pH 5 or more and 8 or less. Specifically, preparing the biodegradable film; may further include introducing the dried solvate into a batch containing an aqueous solvent having a pH of 5 or more and 8 or less. When using an aqueous solvent having a pH within the above-mentioned range, the remaining basic compound is neutralized and the dissolved lignin-containing cellulose-based microfibers are polymerized again, that is, "regenerated" to improve durability of a biodegradable film produced can make it In addition, since a separate solvent such as an aqueous solution of sulfuric acid is not required in addition to the aqueous solvent, the amount of chemicals used in the entire process can be minimized compared to the conventional regeneration process using acidic solvents containing strong acids such as hydrochloric acid, sulfuric acid, and nitric acid. there is. In addition, since the purification process can be drastically reduced through the steps of recovering and reusing residual solvents to be described later, the biodegradable film can be manufactured more economically.

According to an exemplary embodiment of the present invention, the additional drying step may be performed at a temperature of 25 ° C. or more and 70 ° C. or less for 10 minutes or more and 1 hour or less. Specifically, the additional drying step may be performed at a temperature of 25 °C or more and 60 °C or less, 25 °C or more and 40 °C or less, 40 °C or more and 70 °C or less, or 40 °C or more and 60 °C or less. When additional drying is performed at a temperature and time within the above range, a biodegradable film can be rapidly obtained.

According to an exemplary embodiment of the present invention, the yield of the biodegradable film may be 90 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of the solution. The “yield” can be calculated using Equation 2 below from the weight of the biodegradable film actually obtained with respect to the weight of the expected biodegradable film, and the weight of bamboo pulp (W _L ) included in the solution before the reaction It can be calculated from the weight of the additionally dried film (W _F ) for The W _L and W _F may be units of mass.

[Equation 2]

Yield (%) of biodegradable film = 100 * (W _L -W _F )/W _L

When the dissolution rate of the bamboo pulp in the solution product is within the above range, a certain amount of the remaining solvent of the regeneration batch containing the aqueous solvent and the non-regenerated solution product remaining in the residual solvent and the basic compound can be recovered through an iterative process. and the solvent recovery and purification process can be drastically reduced.

According to an exemplary embodiment of the present invention, preparing the biodegradable film; may further include recovering and reusing the residual solvent of the batch containing the aqueous solvent. Specifically, by recovering the residual solvent, it is possible to recover a certain amount of unregenerated solvates and basic compounds remaining in the residual solvent through an iterative process, and reuse them to reduce the amount of raw materials required for manufacturing a biodegradable film. can In addition, since a separate solvent such as an aqueous solution of sulfuric acid is not required in the above process, the biodegradable film can be manufactured more economically by minimizing the amount of chemicals used in the entire process.

One embodiment of the present invention provides a biodegradable film prepared by the above method.

According to an exemplary embodiment of the present invention, the biodegradable film may have a moisture content of 5% or more and 10% or less. Specifically, the biodegradable film may include lignin-containing cellulose-based fine fibers, and may have a low moisture content due to high hydrophobicity due to the lignin component.

According to an exemplary embodiment of the present invention, the biodegradable film may have a basis weight of 5 g/m ² or more and 200 g/m ² or less. Specifically, the biodegradable film has a basis weight of 5 g/m ² or more and 150 g/m ² or less, 5 g/m ² or more and 100 g/m 2 or less, 5 g/m ^{2 or} more and 50 g/m ² or less, 10 g/m ² or more and 200 g/m ² or less, 20 g/m ² or more and 150 g/m ² or less, or 30 g/m ² or more and 100 g/m ² or less. The basis weight may represent the weight per area of the biodegradable film, and may be adjusted according to the use and purpose of the biodegradable film. For example, the biodegradable film may have a basis weight of 35 g/m ² .

According to an exemplary embodiment of the present invention, the biodegradable film has a shrinkage rate of 5% or more and 20% or less, 10% or more and 20% or less, 15% or more and 20% or less, 5% or more and 15% or less, or 5% or more and 10% or less. may have. When the shrinkage rate is within the aforementioned range, the mechanical properties of the biodegradable film may be excellent and the stability may be high.

According to an exemplary embodiment of the present invention, the biodegradable film may have a tensile index of 30 N·m/g or more and 200 N·m/g or less. Specifically, the biodegradable film is 30 N m/g or more and 180 N m/g or less, 30 N m/g or more and 160 N m/g or less, 30 N m/g or more and 140 N m/g or more. g or less, 50 N m/g or more, 200 N m/g or less, 70 N m/g or more, 200 N m/g or less, 90 N m/g or more, 200 N m/g or less, 70 N It may have a tensile index of m/g or more and 180 N m/g or less or 90 N m/g or more and 160 N m/g or less. Specifically, the tensile index of the biodegradable film may be derived by considering basis weight from the measured tensile strength of the biodegradable film. More specifically, it may be calculated by dividing the measured tensile strength of the biodegradable film by the basis weight of the biodegradable film, and may be derived from Equation 3 below.

[Equation 3]

Tensile index (N·m/g) = Tensile strength (N)/Basic weight (g/m ² )

When having a tensile index within the above range, the biodegradable film may have excellent mechanical properties due to the reinforcing effect of the lignin-containing cellulose-based fine fibers, and durability may be improved due to excellent mechanical properties of the biodegradable film.

According to an exemplary embodiment of the present invention, the biodegradable film may have an elongation of 1% or more and 5% or less, 2% or more and 5% or less, 3% or more and 5% or less, or 1% or more and 3% or less. When having an elongation rate within the aforementioned range, the elasticity of the biodegradable film is excellent, so that it may be possible to package foods having a variety of shapes.

According to one embodiment of the present invention, the biodegradable film can be applied in various fields. In particular, since it is manufactured from raw materials derived from nature, it can be applied as a packaging material in direct contact with food or a substitute for household plastic.

Specifically, it can be used as a pouch material containing foods such as snacks, ramen noodles, noodles, snacks, coffee, seasonings, etc., packaging paper for opening parts such as instant rice and cup noodles, and also sanitary vinyl used at home, vinyl gloves, vinyl It can be used as a substitute for wrap.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present invention to those skilled in the art.

manufacturing example

Preparation Example 1: Preparation of pulp

Preparation Example 1-1: Preparation of bamboo pulp

As a bamboo raw material, bamboo chips were prepared by removing nodes of the bamboo using a king stem and a pine stem, and then cutting the bamboo into 5 to 6 cm in length and 1 to 1.5 cm in width.

Thereafter, a mixed solvent was prepared by mixing glycol ether as a glycol ether solvent and sulfuric acid as an acid. At this time, the volume ratio of glycol ether and sulfuric acid contained in the prepared mixed solvent was adjusted to 97.3:2.7, and the molar concentration of sulfuric acid was adjusted to 0.5 M.

Thereafter, at a mixing ratio of 900 g of the mixed solvent to 300 g of the dry weight of the bamboo chips, it was put into a high-pressure steam treatment device (autoclave, HST 506-6, Hanbaek ST, Korea), reacted at 120 ° C. for 60 minutes, and 10 to 200 mesh with distilled water. After washing and separating unreacted samples, bamboo pulp (yield: 60±5%) was prepared.

Preparation Example 1-2: Preparation of Wood Pulp

Using radiata pine as a raw material, it was put into a high-pressure steam treatment device (autoclave, HST 506-6, Hanbaek ST, Korea) at a mixing ratio of 2.4Kg of mixed solvent to 300g of dry weight of wood chips, reacted at 120℃ for 120 minutes, and washed. Except for one, wood pulp (yield: 63±1%) was prepared in the same manner as in Preparation Example 1-1.

Preparation Example 2: Preparation of Pulp Slurry and Solution Cargo

Preparation Example 2-1

A bamboo pulp slurry was prepared by mixing 60 g of the bamboo pulp prepared in Preparation Example 1-1 with 940 mL of an aqueous solution of 0.25 N sodium hydroxide. At this time, the molar concentration of sodium hydroxide included in the prepared bamboo pulp slurry was adjusted to 1.75 M. Thereafter, 1 L of the bamboo pulp slurry was homogenized using a homogenizer (Silverson Co.) at 3,000 rpm for 5 minutes, and the homogenized bamboo pulp slurry was frozen and dissolved at a temperature of -20 ° C or lower. The above homogenization, freezing and dissolution process was repeated two more times to obtain a solution product (homogenization, freezing and dissolution a total of three times).

At this time, based on 100 parts by weight of the solution, the content of sodium hydroxide was adjusted to 7 parts by weight and the content of bamboo pulp to 6 parts by weight.

Preparation Example 2-2

In Preparation Example 2-1, a solution was prepared in the same manner as in Preparation Example 2-1, except that the content of sodium hydroxide was adjusted to be 3 parts by weight based on 100 parts by weight of the solution.

Preparation Example 2-3

In Preparation Example 2-1, a solution was prepared in the same manner as in Preparation Example 2-1, except that the content of sodium hydroxide was adjusted to 5 parts by weight based on 100 parts by weight of the solution.

Preparation Example 2-4

In Preparation Example 2-1, a solution was prepared in the same manner as in Preparation Example 2-1, except that the content of sodium hydroxide was adjusted to be 9 parts by weight based on 100 parts by weight of the solution.

Preparation Example 2-5

In Preparation Example 2-1, a solution was prepared in the same manner as in Preparation Example 2-1, except that the amount of bamboo pulp was adjusted to be 3 parts by weight based on 100 parts by weight of the solution.

Production Example 2-6

In Preparation Example 2-1, a solution was prepared in the same manner as in Preparation Example 2-1, except that the amount of bamboo pulp was adjusted to 9 parts by weight based on 100 parts by weight of the solution.

Production Example 2-7

In Preparation Example 2-1, a wood pulp slurry and a solution were prepared in the same manner as in Preparation Example 2-1, except that the wood pulp prepared in Preparation Example 1-2 was used.

solution cargo pulp NaOH concentration
(parts by weight) pulp content
(parts by weight) Preparation Example 2-1 manufacturing example
1-1 7 6 Preparation Example 2-2 manufacturing example
1-1 3 6 Preparation Example 2-3 manufacturing example
1-1 5 6 Preparation Example 2-4 manufacturing example
1-1 9 6 Preparation Example 2-5 manufacturing example
1-1 7 3 Production Example 2-6 manufacturing example
1-1 7 9 Production Example 2-7 manufacturing example
1-2 7 6

Example: Preparation of biodegradable film

Example 1

The solution prepared in Preparation Example 2-1 was cast on an area of about 62 cm ² , and dried in a vacuum dryer (BF-30VO, BioFree, Korea) at 50 ° C. for 15 minutes to remove moisture.

A 3L regeneration batch containing distilled water was prepared, and the water-removed solution was put into the 3L regeneration batch to form a film.

Thereafter, the remaining chemicals were washed with an additional 3L of distilled water and dried in a 40 ° C. gel dryer (SE 1160 Hofer Drygel Sr., Phamacia Biotech Inc., USA) until the moisture content reached 5 to 10% to form a biodegradable film. was manufactured.

Example 2

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that the solution prepared in Preparation Example 2-3 was used.

Example 3

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that the solution prepared in Preparation Examples 2-4 was used.

Example 4

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that the solution prepared in Preparation Examples 2-6 was used.

Comparative Example 1

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that the solution prepared in Preparation Examples 2-7 was used.

Comparative Example 2

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that a 3L regeneration batch containing 5% sulfuric acid aqueous solution was used.

Comparative Example 3

In Example 1, a biodegradable film was prepared in the same manner as in Example 1, except that the solution prepared in Preparation Examples 2-6 was used and a 3L recycling batch containing 5% sulfuric acid aqueous solution was used.

Comparative Example 4

In Example 1, the same preparation method as in Example 1 was performed, except that the solution prepared in Preparation Example 2-2 was used.

Comparative Example 5

In Example 1, the same preparation method as in Example 1 was performed, except that the solution prepared in Preparation Examples 2-5 was used.

Experimental example

Experimental Example 1: Evaluation of physical properties of film

Physical properties of the biodegradable film samples prepared in Examples 1 to 4 and Comparative Examples 1 to 5 were measured according to the following measurement method and are shown in Table 2 below. At this time, the tensile index was derived by adjusting the basis weight of the biodegradable film sample to 35 g/m ² and using Equation 3 from the measured tensile strength and basis weight of the sample.

-Shrinkage rate (%): derived by converting the area of the film made of a regenerated biodegradable film into a ratio based on the area cast in the initial Petri dish

-Tensile strength (MPa): Samples are prepared by cutting them into 1 cm horizontally and 3 cm vertically, and the load cell load of the measuring instrument is 10 N, the tensile speed is 1 mm/min, and the distance between measuring instruments is The tensile strength of the sample was measured through a tensile tester (OTT-005, Oriental TM, Korea) set at 1 cm.

-Elongation rate (%): Indicates the rate at which the material is elongated to the point of fracture when measuring tensile strength, measured in a tensile tester

pulp solution cargo arrangement dissolution rate
(%) shrinkage rate
(%) tensile strength
(MPa) tensile index
(N m/g) elongation rate
(%) Example 1 manufacturing example
1-1 manufacturing example
2-1 Distilled water 70.1 11.1 41.4 49.7 3.4 Example 2 manufacturing example
1-1 manufacturing example
2-3 Distilled water 69.0 10.2 37.3 44.8 3.1 Example 3 manufacturing example
1-1 manufacturing example
2-4 Distilled water 67.1 9.3 40.6 48.7 4.3 Example 4 manufacturing example
1-1 manufacturing example
2-6 Distilled water 63.9 19.5 15.8 18.9 1.5 Comparative Example 1 manufacturing example
1-2 manufacturing example
2-7 Distilled water 65.1 14.4 19.53 23.4 2.48 Comparative Example 2 manufacturing example
1-1 manufacturing example
2-1 5%
H ₂ SO ₄ 70.1 9.9 39.56 47.5 4.4 Comparative Example 3 manufacturing example
1-1 manufacturing example
2-7 5%
H ₂ SO ₄ 70.1 10.2 9.22 11.1 0.93 Comparative Example 4 manufacturing example
1-1 manufacturing example
2-2 Distilled water 32.1 - - - - Comparative Example 5 manufacturing example
1-1 manufacturing example
2-5 Distilled water 91.4 - - - -

Referring to Tables 1 and 2, the shrinkage rate of the biodegradable film is higher than that of the biodegradable film according to Examples 1 to 4 made of bamboo as a raw material than the biodegradable film according to Comparative Example 1 made from radiata, which is wood. It was confirmed that it appeared low and was stable, and the tensile strength of the film was also shown to be more than twice as high. It was also confirmed that the elongation rate was excellent in the film prepared using the bamboo raw material. Through this, it can be seen that the biodegradable film according to an exemplary embodiment of the present invention has excellent mechanical properties such as shrinkage, tensile strength and elongation.

On the other hand, like the biodegradable film according to Comparative Example 2 using the regeneration batch of 5% sulfuric acid aqueous solution, it was confirmed that the biodegradable film according to Example 1 was also stably regenerated in the distilled water regeneration batch. Furthermore, it was confirmed that the biodegradable film according to Example 1 regenerated in water exhibited higher tensile strength than the biodegradable film according to Comparative Example 2 regenerated in aqueous sulfuric acid solution. From this, it can be seen that the biodegradable film according to the present invention can stably provide a biodegradable film with excellent physical properties not only in an acidic solution generally used for forming regenerated cellulose, but also in an aqueous solvent having a pH of 5 or more and 8 or less. there is.

On the other hand, in the case of the biodegradable films according to Examples 1 to 3 and Comparative Example 4, the pulp content was maintained at 6 parts by weight, and the NaOH concentration was adjusted to confirm the dissolution and production of the biodegradable film according to the NaOH concentration. did In the case of Comparative Example 4 having a NaOH concentration of 3%, it was confirmed that a film was not formed in the distilled water regeneration batch due to a low dissolution rate. On the other hand, in the case of the biodegradable films according to Examples 1 to 3, that is, when the NaOH concentration was adjusted to 5% or more, the dissolution rate was 60% or more, and it was confirmed that the film was stably formed in the distilled water regeneration batch.

On the other hand, in the case of the biodegradable films according to Examples 1, 4 and Comparative Example 5, the concentration of NaOH was maintained at 7% and the concentration of the pulp was adjusted to confirm the manufacture of dissolving and biodegradable films according to the pulp content. did In the case of the film according to Comparative Example 5 having a pulp concentration of 3 parts by weight, while the dissolution rate was high, it was confirmed that film formation was difficult because the viscosity was not higher than a certain level. In the case of Example 1 having a pulp concentration of 6 parts by weight, a dissolution rate of 70% was shown, and it was confirmed that the tensile strength of the biodegradable film was as high as 41.4 MPa. In the case of the biodegradable film according to Example 4 having a pulp concentration of 9 parts by weight or more, the dissolution rate was slightly high at 64%, while the viscosity of the solution was high, making it difficult to process and showing low tensile strength.

Experimental Example 2: Evaluation of biodegradable film yield and solvent recovery rate

After forming a total of three biodegradable films from the 3L distilled water regeneration batch of Example 1, the yield of the biodegradable films was evaluated using Equation 2 above. In addition, the solvent recovery rate was evaluated by measuring the weight of the remaining foreign matter obtained by concentrating and drying the remaining solvent in the regeneration batch and comparing it with the weight of NaOH contained in the solution according to Preparation Example 2-1, and showed up

Estimated film weight (g) Manufactured film weight (g) Solution before reaction NaOH (g) Residual foreign matter in regeneration batch after reaction (g) Example 1 0.61 0.55 1.8 2.1

Referring to Table 3, the pulp contained in the solution cargo per film before reaction is about 0.61 g, which is about 10% lower than the weight of the film expected from the content of the pulp contained in the solution cargo before inputting into the regeneration batch. A biodegradable film of 0.55 g was obtained. That is, it was confirmed that the yield of the process of preparing the biodegradable film from the solution was about 90%. In addition, it was confirmed that the amount of foreign substances measured by concentrating and drying the distilled water regeneration batch was 2.1 g, higher than the NaOH content of 1.8 g contained in the solution before the reaction. Through this, it can be seen that a certain amount of unregenerated pulp, in addition to NaOH contained in the solution before the reaction, remains in the residual solvent in the distilled water regeneration batch after obtaining the biodegradable film of the present invention. Therefore, by recovering the residual solvent, it is possible to recover a certain amount of unregenerated pulp remaining in the residual solvent, and the recovered residual solvent can be reused without a separate purification process, thereby reducing the amount of raw materials required for manufacturing a biodegradable film. it can be seen that there is That is, since the manufacturing method of the biodegradable film of the present invention does not require a separate solvent such as an aqueous solution of sulfuric acid in addition to the aqueous solvent, it is possible to dramatically reduce the solvent recovery and purification process by minimizing the chemicals used in the entire process. can

The foregoing detailed description is intended to illustrate and explain the present invention. In addition, the foregoing merely represents and describes preferred embodiments of the present invention, and as described above, the present invention can be used in various other combinations, modifications, and environments, and the scope of the inventive concept disclosed herein, the foregoing Changes or modifications are possible within the scope equivalent to the disclosure and / or within the scope of skill or knowledge in the art. Accordingly, the above detailed description of the invention is not intended to limit the invention to the disclosed embodiments. Also, the appended claims should be construed to cover other embodiments as well.

Claims (13)

Forming bamboo pulp by reacting a bamboo raw material with a mixed solvent of a glycol ether solvent and an acid;
mixing the bamboo pulp with a basic compound to prepare a bamboo pulp slurry;
homogenizing the bamboo pulp slurry to prepare a solution product; and
Including; preparing a biodegradable film using the solvate,
Preparing the biodegradable film; Method for producing a biodegradable film using an aqueous solvent of pH 5 or more and 8 or less.
According to claim 1,
The content of the glycol ether-based solvent is based on 100 parts by weight of the mixed solvent, a method for producing a biodegradable film of 90 parts by weight or more and 100 parts by weight or less.
According to claim 1,
A method for producing a biodegradable film in which the molarity of the acid contained in the mixed solvent is 0.5 M or more and 2.0 M or less.
According to claim 1,
The volume ratio of the glycol ether-based solvent and the acid contained in the mixed solvent is 88:12 or more and 98:2 or less.
According to claim 1,
The amount of the basic compound is 5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the solution.
According to claim 1,
The method of producing a biodegradable film, wherein the dissolution rate of the bamboo pulp in the solution cargo is 50% or more and 100% or less.
According to claim 1,
The method for producing a biodegradable film in which the content of the bamboo pulp is 5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the solution.
According to claim 1,
Preparing the solution cargo; is,
Freezing and dissolving the homogenized bamboo pulp slurry; method for producing a biodegradable film further comprising.
According to claim 1,
Preparing the biodegradable film;
Casting the solution product into a film shape and drying it; and
Method for producing a biodegradable film that further comprises; injecting the dried solvate into a batch containing the aqueous solvent.
According to claim 9,
Method for producing a biodegradable film that further comprises; recovering and reusing the residual solvent of the batch containing the aqueous solvent.
According to claim 1,
The yield of the biodegradable film is a method for producing a biodegradable film of 90 parts by weight or more and 100 parts by weight or less based on 100 parts by weight of the solution.
A biodegradable film prepared by the method according to claim 1.
According to claim 12,
A biodegradable film having a tensile index of 30 N·m/g or more and 200 N·m/g or less.