KR101093389B1 - Biodegradable multi-layer sheet having an excellent anti-fogging and releasing property and preparing process thereof - Google Patents

Abstract

The present invention relates to a biodegradable multilayer sheet having excellent antifogging property and mold release property, and a method of manufacturing the same, in which the antifogging property is maintained even when the antifogging sheet is wound in a roll form while solving the problems of the conventional antifogging sheet. The biodegradable multilayer sheet having excellent antifogging property and releasability of the present invention comprises an inner layer (A) consisting of a polylactic acid alone or a composition consisting of at least one selected from an aliphatic polyester, an aromatic-aliphatic polyester or a polylactic acid copolymer except for a polylactic acid, and A multilayer sheet designed to be composed of a surface layer (B) made of a composition comprising a release agent and a polylactic acid, characterized in that the anti-fogging coating layer is formed at 0.01 to 1.00 g / m 2 on one surface of the multilayer sheet.

As the biodegradable multilayer sheet having excellent anti-fogging property and mold release property of the present invention configured as described above is provided with excellent mold release property to the sheet itself, it is not necessary to perform separate silicone release coating, so that anti-fogging due to formation of a release layer in the prior art Problems such as deterioration of antifogging property due to the transfer problem of the silicone release coating to the coating layer can be solved.

Biodegradable, scratch resistant, antifogging, polylactic acid, trays, sheets.

Description

Biodegradable multi-layer sheet having an excellent anti-fogging and releasing property and preparing process etc.

The present invention relates to a biodegradable multilayer sheet having excellent antifogging property and mold release property and a method for manufacturing the same, and more specifically, even if the antifogging sheet is wound in a roll form while having excellent mold release property by solving the problem of the conventional antifogging sheet. The present invention relates to a biodegradable multilayer sheet having excellent antifogging property and mold release property and its manufacturing method.

In general, synthetic plastics are used for various purposes all over the world as packaging materials that are indispensable to modern life because of their excellent properties and cheap and light properties. However, synthetic plastics having the above-mentioned characteristics are environmental problems due to their advantages and disadvantages of poor decomposition, and thus, various countries have recently been interested in finding solutions to them. In other words, the conventional methods of landfilling, incineration and regeneration have been mainly used for treating synthetic plastics, but these methods do not completely solve the environmental pollution problem.

Therefore, attention is now focused on the development of so-called degradable plastics, which makes it possible to decompose the used plastic by itself. Currently, various kinds of degradable plastics have been developed from various technologies and raw materials. Among them, polylactic acid (hereinafter referred to as 'PLA') is produced in large quantities and inexpensively by the fermentation method of L-lactic acid, and under composting conditions Its fast decomposition rate, excellent resistance to mold, and odor resistance to food have expanded its range of applications. Such PLA is currently making various attempts to impart suitable properties for each country. Among these, in the field of food packaging trays used for single use, the anti-fogging function that suppresses frost on the surface of the tray is the most important technology. The sheet surface coating method etc. of an antifog component have been used. In the case of the above-described sheet internal addition method, the anti-fogging function is generally provided through the sheet surface coating method because it is not suitable for use due to the bleed-out phenomenon of the anti-fogging component and the problem of clouding over time. In the case of PLA antifogging sheet, for example, Korean Patent No. 1996-004395 proposes a coating method using an aliphatic polyester composed of aliphatic dicarboxylic acid and aliphatic diol, which is a biodegradable coating agent. There are disadvantages, but Japanese Patent No. Hei 9-221555, U.S. Patent No. 4,414,768 proposes a method using the hydrophilicity of polyvinyl alcohol, but these have the disadvantage of not exhibiting long-term effects in scratch resistance and antifogging persistence. In addition, the Republic of Korea Patent 10-0722516 has been proposed a coating method using a water-dispersed copolyester, this also is not practical to use because there is no mention of transparency and food stability of the copolyester according to the application amount.

In addition, in the case of anti-fogging coatings that are food-safe, conventionally, surfactants include quaternatery ammonium salts, alkylsulphates, alkylsulfonates, alkylphosphonates, alkylphosphonates, Amphoteric strains are used and are prepared by blending various binders into these surfactants. However, most of these antifogging agents have excellent scratch resistance due to the lack of scratch resistance, but the antifogging property is deteriorated in the scratch area generated between tray forming processes. It is true.

Furthermore, in the case of sheets, in general, in order to provide mold release between trays and molds and mold release between trays and trays in a tray forming process and a tray packaging process, a coating is required to give a release property on one side of the sheet. In the situation where silicone is used, these silicones are non-crosslinkable, so that when the sheet is rolled up, these silicone components are transferred to the antifogging coating surface, which is the opposite side of the sheet. In this case, the silicon component transferred to the antifogging surface has a very bad effect on the antifogging property, and there is a problem that the antifogging function is broken from the region where the silicon is transferred. However, there is no current technique for forming a stable coating film by appropriately crosslinking the silicone coating at a drying temperature of 90 ° C. or lower, and thus, as a method for minimizing the transfer of the silicone coating so as not to adversely affect the antifogging property. Since the situation is simply to improve the coating process, a fundamental countermeasure is urgently required.

Accordingly, the present invention solves the problems of the conventional anti-fogging sheet as described above to provide a biodegradable multilayer sheet excellent in anti-fogging property and releasability, even if the anti-fogging sheet is wound in a roll form, the anti-fogging property is maintained as it is It is to.

Another object of the present invention is to provide a method for easily manufacturing a biodegradable multilayer sheet having excellent release properties and anti-fogging properties by solving the problems of the conventional anti-fogging sheet as described above.

Still another object of the present invention is to provide a tray having excellent anti-fogging function by using a biodegradable multilayer sheet having excellent anti-fogging property and releasability by the above method.

The object of the present invention described above is to form an inner layer (A) with a composition consisting of an aliphatic polyester, an aromatic-aliphatic polyester or a polylactic acid copolymer, except for polylactic acid and polylactic acid, and a polylactic acid having releasability on the surface of the inner layer. By designing a multi-layer sheet to form a surface layer (B) with a composition consisting of a coating and then performing anti-fogging coating on one surface layer of the multi-layer sheet can provide a biodegradable multi-layer sheet having sufficient anti-fogging function and release function even after the tray molding. It could be achieved by revealing.

Biodegradable multilayer sheet excellent in the antifogging property and releasability of the present invention for achieving the above object;

An inner layer (A) of a composition consisting of polylactic acid alone or a composition consisting of at least one selected from aliphatic polyesters, aromatic-aliphatic polyesters or polylactic acid copolymers excluding polylactic acid; And

Multi-layered sheet designed to consist of a surface layer (B) of a composition consisting of a release agent and a polylactic acid,

It is characterized in that the anti-fogging coating layer is formed in 0.01 to 1.00g / ㎡ on one surface of the multilayer sheet.

According to another configuration of the present invention, the composition constituting the multilayer sheet is characterized in that the inner layer (A) in the total content of 90.0 to 60.0 parts by weight, the surface layer (B) is composed of 10.0 to 40.0 parts by weight.

According to another configuration of the present invention, the composition constituting the inner layer (A) of the multi-layered sheet has a polylactic acid of 90.0 parts by weight or more in total content, aliphatic polyester other than polylactic acid, aromatic-aliphatic polyester or polylactic acid The sum of the copolymers is 10.0 parts by weight or less.

According to another configuration of the present invention, the composition constituting the surface layer (B) of the multi-layered sheet is characterized in that the polylactic acid in the total content of 95.0 to 99.5 parts by weight and the release property imparting substance is 0.5 to 5.0 parts by weight. .

According to another configuration of the present invention, the polylactic acid constituting the multilayer sheet is obtained by polymerizing lactic acid, and in the case of the polylactic acid used in the present invention, L-lactic acid, D-lactic acid or L, D It is composed of lactic acid, the number average molecular weight is 10,000 or more, these polylactic acid is characterized in that it can be used alone or in combination.

According to another configuration of the present invention, the aliphatic polyester is an aliphatic dicarboxylic acid or derivative thereof ROOC (CH ₂ ) n COOR '(R, R' is hydrogen or an alkyl group, n is an integer of 2 to 14) structure At least one selected from the group consisting of succinic acid, glutaric acid, malonic acid, oxalic acid, adipic acid, sebacic acid, azelaic acid, nonanedicarboxylic acid and alkyl or aryl ester derivatives thereof, and glycols are HO Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or propylene glycol having a structure of-(CH ₂ ) n-OH (n is an integer of 2 or more) , A group consisting of alkylene glycol and polyalkylene glycol composed of 1,4-cyclohexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, neopentyl glycol, and tetramethylene glycol or represented by the following general formula (1) Capable of forming branch structure 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,2-hexane which are aliphatic dihydric alcohols Diol, 1,3-hexanoic diol, 1,4-hexanediol, 1,5-hexanediol, 1,2-octanediol, 1,3-octanediol, 1,4-octanediol, 1,5-octane It is characterized in that the group consisting of diols, 1,6-octanediol and the like can be used.

General formula (1)

In General Formula (1), R ₁ is an alkylene group of C ₂ to C ₈ , and R ₂ is an alkyl group of C ₂ to C ₈ .

According to another configuration of the present invention, the aromatic-aliphatic polyester is an aromatic component of dicarboxylic acid or derivative thereof of ROOC-Ar-COOR '(R, R' is hydrogen or alkyl group) structure of terephthalic acid, phthalic acid, iso Phthalic acid, naphthalene 2,6-dicarboxylic acid, diphenylsulfonic acid dicarboxylic acid, diphenylmethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, cyclohexanedicarboxylic acid At least one selected from the group consisting of an acid or an alkylene ester thereof, and an aliphatic dicarboxylic acid or a derivative thereof may include ROOC (CH ₂ ) nCOOR '(R, R' is hydrogen or an alkyl group, n is 2 to 14; At least one member selected from the group consisting of succinic acid, glutaric acid, malonic acid, oxalic acid, adipic acid, sebacic acid, azelaic acid, nonanedicarboxylic acid and their alkyl or aryl ester derivatives Glycols are HO- (CH ₂ ) n-O Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or propylene glycol, 1,4-cyclo A group consisting of alkylene glycol or polyalkylene glycol composed of hexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, neopentyl glycol, tetramethylene glycol, or a branched structure represented by the general formula (1) 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,2 which may be aliphatic dihydric alcohols -Hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,2-octanediol, 1,3-octanediol, 1,4-octanediol, 1,5- It is characterized in that the group consisting of octanediol, 1,6-octanediol and the like can be used.

According to another configuration of the present invention, the polylactic acid copolymer is a composition consisting of a unit consisting of dicarboxylic acid or derivatives thereof and aliphatic glycols, L-lactic acid, Succinic acid, glutaric acid, malonic acid, oxalic acid, adipic having a structure of D-lactic acid or L, D-lactic acid, ROOC (CH ₂ ) nCOOR '(R, R' is hydrogen or an alkyl group, n is an integer from 2 to 14) Acid, sebacic acid, azelaic acid, nonanedicarboxylic acid and alkyl or aryl ester derivatives thereof, dicarboxylic acid having a structure of ROOC-Ar-COOR '(R, R' is hydrogen or an alkyl group) or a derivative thereof and terephthalic acid, Phthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, diphenylsulfonic acid dicarboxylic acid, diphenylmethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, cyclohexane Dicarboxylic acid, or alkylene esters thereof At least one member selected from the group, and aliphatic glycols are ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1, having a structure HO- (CH ₂ ) n-OH Alkylene glycol or poly consisting of 5-pentanediol, 1,6-hexanediol or propylene glycol, 1,4-cyclohexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, neopentyl glycol, tetramethylene glycol 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2 which are aliphatic dihydric alcohols capable of forming a branched structure represented by the group consisting of alkylene glycols or the general formula (1) -Pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,2- The group consisting of octanediol, 1,3-octanediol, 1,4-octanediol, 1,5-octanediol, 1,6-octanediol and the like can be used.

According to another configuration of the present invention, the release property-providing material is silicon oxide, such as silica, silica gel, colloidal silica, wet silica, dry silica, titanium oxide, calcium carbide, kaolin, kaolinite, clay, talc, alumina, alumina sol, Inorganic particles such as zeolite, graphite, zirconium sol, feldspar, molybdenum disulfide, carbon black, barium salt, barium sulfate, antimony sol, calcium silicate, aluminum silicate, calcium sterate, polystyrene, polymethyl methacrylate, Methyl methacrylate copolymer, methyl methacrylate copolymer, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguamine-formaldehyde condensate, benzoguanamine resin, melamine-formaldehyde condensate, Benzoguamine-melamine-formaldehyde condensate, crosslinked silicone resin, silicone It is characterized in that at least one selected from organic particles, such as resin, gelatin, starch.

According to another configuration of the present invention, the anti-fogging coating layer is preferably made of a surfactant using an acrylic resin as a binder.

According to another configuration of the present invention, the surfactant is quaternatery ammonium salt (Quaternatery ammonium salt), alkylsulfate (Alkylsulfate), alkylsulfonate (Alkylsulfonate), alkylphosphonate (Alkylphosphonate), positive (Amphoteric) system It is characterized by using one or more included.

Method for producing a biodegradable multilayer sheet excellent in the anti-fogging property and releasability of the present invention for achieving the above another object;

Polylactic acid resin alone or at least 90.0 parts by weight of polylactic acid resin and at least 10.0 parts by weight of at least one resin selected from aliphatic polyester, aromatic-aliphatic polyester or polylactic acid copolymer except polylactic acid resin Melting at a temperature of from 250 ° C. to pass through the sheet inner layer (A);

Mixing 95.0 to 99.5 parts by weight of a polylactic acid resin and 5.0 to 0.5 parts by weight of a release property-providing material, and then melting the mixture at a temperature of 180 to 250 ° C. and passing it through the sheet surface layer (B);

Discharging each of the passed compositions through a slip die to produce a sheet having a B: A: B structure;

Performing a corona discharge treatment on one side of the sheet prepared above;

Preparing an antifogging coating solution by mixing the antifogging agent with water or an organic solvent;

Applying the antifogging coating solution prepared in the step to one surface of the corona discharge treated sheet; And

It characterized in that it comprises a step of drying the coating liquid applied after the coating treatment in the step.

The tray having excellent releasability and anti-fogging property of the present invention for achieving the above another object is characterized in that molded into the biodegradable multilayer sheet according to the present invention.

The biodegradable multilayer sheet according to the present invention, in the manufacturing process, and other additives, depending on the application, such as a sunscreen, antibacterial / deodorant, heat stabilizer, light stabilizer, flame retardant, antistatic agent, antioxidant, pigment, etc. It is also possible to add.

The biodegradable multilayer sheet having excellent antifogging property and releasability of the present invention constituted as described above is made of a polylactic acid alone or an inner layer of a composition consisting of an aliphatic polyester and / or an aromatic-aliphatic polyester and / or a polylactic acid copolymer except for polylactic acid. The surface layer (B) made of a composition consisting of (A) and a polylactic acid having releasability is composed of a multilayer sheet in the form of B / A / B, and an anti-fogging coating layer is applied on one surface thereof, so that excellent releasability is given to the sheet itself. By not having to release the silicone release coating, problems such as deterioration of the antifogging property due to the transfer problem of the silicone release coating to the antifogging coating layer due to the formation of the release layer in the prior art can be solved.

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

As described above, the sheet substrate presented in the present invention includes an inner layer (A) made of aliphatic polyester and / or aromatic-aliphatic polyester and / or polylactic acid copolymer except polylactic acid alone or polylactic acid, and polylactic acid having releasability. It is characterized in that the surface layer (B) consisting of a B / A / B multilayer structure. The sheet inner layer (A) is made of a polylactic acid and an aliphatic polyester and / or an aromatic-aliphatic polyester and / or a polylactic acid copolymer. According to the brittle characteristic of the drawback of the drawback (break) characteristics of the tray during the molding process or the distribution process can be broken due to the impact is not preferable. Therefore, polylactic acid alone is most preferred in terms of sheet extrudability, workability, and transparency. However, when impact resistance is required according to the use of the tray, polylactic acid may be added to polylactic acid to enhance impact resistance of polylactic acid. The sheet may be extruded by mixing a proper amount of aliphatic polyester and / or aromatic-aliphatic polyester and / or polylactic acid copolymer except. In this case, it is important to adjust the appropriate dosage because the impact resistance and the transparency reduction of the sheet due to the application of the aliphatic polyester and / or the aromatic-aliphatic polyester and / or the polylactic acid copolymer except for the polylactic acid should be considered at the same time. . Even if any one of aliphatic polyester, aromatic-aliphatic polyester, and polylactic acid copolymer is used, it is difficult to secure the transparency of the sheet when 10.0 parts by weight or more is added based on the inner layer (A) of the sheet. The application amount is limited to 10.0 parts by weight or less, 5.0 parts by weight or less for aromatic-aliphatic polyester and 10.0 parts by weight or less for polylactic acid copolymer. On the contrary, in order to provide the flexibility of the sheet, impact resistance is improved only when 1.0 part by weight or more of aliphatic polyester, 0.1 part by weight or more of aromatic-aliphatic polyester and 1.0 part by weight or more of polylactic acid copolymer are added. . Any of aliphatic polyesters, aromatic-aliphatic polyesters, and polylactic acid copolymers may be applied, but in terms of compatibility with polylactic acid, polylactic acid copolymers and aliphatic polyesters are superior to aromatic-aliphatic polyesters. On the other hand, aromatic-aliphatic polyesters are advantageous over polylactic acid copolymers and aliphatic polyesters in terms of flexibility.

In addition, the surface layer (B) of the sheet is made of polylactic acid having releasability, and in the case of a release property imparting material, it should be maintained at 0.5 to 5.0 parts by weight based on the total composition of the surface layer (B) of the sheet. In the case of a release property-providing material serves to prevent the adhesion between the sheets, if excessively applied may impair the transparency and impact resistance of the sheet. In addition, when the release agent is a particle, the surface of the sheet may be scratched, so when the release agent is excessively used, the anti-fogging property may be impaired. Therefore, preferably 3.0 to 1.0 parts by weight is the best. In addition, in the case of the release-modifying substance, it is important to select and use particles having a diameter of 1.0 to 10.0 μm, preferably 2.0 to 6.0 μm, because the release property and transparency of the sheet depend on the size of the particles. It is preferable that the composition of the surface layer (B) of the sheet which consists of such a composition is adjusted to 10.0-40.0 weight part in the whole sheet composition. At 10.0 parts by weight or less, it is difficult to fully exhibit the releasability of the sheet, and when it is 40.0 parts by weight or more, the inner layer (A) content of the sheet is small, and thus the impact resistance of the sheet is difficult to be exhibited, and due to the influence of the thickened surface layer (B) It is not preferable because it may damage transparency.

The inner layer (A) and the surface layer (B) constituting the multilayer sheet of the present invention mainly apply the same polylactic acid, but the inner layer (A) of the sheet is an aliphatic polyester and / or an aromatic-aliphatic polyester and / or a polylactic acid. Since the polylactic acid copolymer is included up to 10.0 parts by weight, and the surface layer (B) of the sheet includes a release release imparting material up to 5.0 parts by weight, it is required to control the melt viscosity of each sheet during sheet extrusion. At this time, the most important is the temperature conditions, it is good to process in a temperature range of 180 to 250 ℃, preferably 200 to 230 ℃. This is because there is an effect of doubling the flexibility of the sheet composition by minimizing thermal decomposition of the resin composition, and is most suitable for controlling the flow of the molten polymer discharged from the die by maintaining a sufficient melting temperature. In addition, pigments, stabilizers, antistatic agents, ultraviolet absorbers, antioxidants, flame retardants, mold release agents, lubricants, dyes, pharmaceuticals, various elastomers, various fillers, and the like may be used as various additives to impart additional sheet functionality.

By forming the anti-fog coating layer consisting of an acrylic resin and a surfactant on one surface of the sheet to which the release property is imparted as described above, the anti-fogging function is imparted to the sheet. The antifogging coating layer is applied to one side of the sheet, and an acrylic resin is used as a binder. As the antifogging surfactant, a quaternary ammonium salt, an alkyl sulfate, an alkylsulfonate, an alkyl phosphonate, and one containing at least one positive system are used. do.

The anti-fogging coating according to the present invention described above is preferably prepared so that the content of solids is 0.1 to 10.0 parts by weight based on 100 parts by weight of the total coating solution, and more preferably the content of solids is 1.0 to 5.0 parts by weight. Can be. When the content of the solid content is less than 0.1 part by weight, it is not sufficient to express the film formation and antifogging function of the coating layer, and when it exceeds 10.0 parts by weight, the transparency of the film is affected and not preferable. When the solids content is coated with a general large-diameter gravure coating, the thickness of the dried coating film is 0.01 to 1.00 g / m 2, preferably 0.03 to 0.10 g / m 2, indicating sufficient coating properties and economic efficiency. Most preferred.

On the other hand, the solvent used in the antifogging coating liquid is preferably an aqueous coating liquid substantially containing water as a main medium, and the coating liquid used in the present invention inhibits the effects of the present invention for the purpose of improving coating properties, improving transparency, and the like. You may contain the appropriate amount of organic solvents of the grade which does not. For example, isopropyl alcohol, butyl cellosolve, t-butyl cellosolve, ethyl cellosolve, acetone, ethanol, methanol and the like can be preferably used. However, when a large amount of organic solvent is contained in the coating liquid, the content may be 10 parts by weight or less, preferably 5 parts by weight or less in the coating liquid since there is a risk of explosion in the drying, stretching and heat treatment processes when applied to the in-line coating method. Shall be. In the coating process, the antifogging coating solution prepared on one surface of the sheet is coated to form an antifogging coating layer. Specifically, there is no particular limitation as a method of applying the antifogging coating liquid, but a meyer bar method, a gravure method, a spray method, and the like are used. It is preferable to perform a corona discharge treatment in order to improve the adhesiveness and applicability | paintability with a sheet | seat. In addition, alcohols such as ethanol, isopropanol and isopropyl alcohol, ethers such as ethyl cellosolve and t- butyl cellosolve, and methyl to improve the stability, wetting and coating leveling of the antifogging coating solution Ketones, such as ethyl ketone and acetone, and amines, such as dimethylethanolamine, can be mixed and used 1 or more types. In addition, the thickness of the biodegradable sheet is usually 100 to 2000 µm, preferably 300 to 1000 µm. The sheet produced as described above facilitates desorption with a mold through excellent mold release property during tray molding, and the mold release property between the trays is effective and has excellent anti-fogging properties.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

First, the measurement and evaluation methods necessary for the explanation of the present invention were performed under the following conditions.

(1) transparency;

A sample of 10 cm x 10 cm sample was placed vertically in an HAITMATIC DIGITAL HAZEMETER (manufactured by Nippon Densoku Co., Ltd.) in a vertical position, and light was transmitted through light having a wavelength of 400 to 700 nm in a direction perpendicular to the vertically placed sample. The value was measured.

At this time, the haze value was calculated by Equation 1 below.

Haze (%) = (1- amount of scattered light / total transmission of light) × 100

(2) flexibility;

When 10 samples of 5 cm long and 5 cm long specimens prepared under the same conditions were repeatedly folded at 90 ° C. or more, 10 times, the cracks were 0% to 10%, △, 50% or less, △, and 50% or more. Is indicated.

(3) surface roughness (DIN-4768);

The surface of the sheet was measured by a contact method using a 5 micrometer R needle with a measuring length of 2.5 mm, a scanning number of 40, and a cutoff value of 0.25 mm. Four repeated measurements of the same sample were made as the average of the three remaining data except for the largest one.

(4) coefficient of friction (ASTM D 1904);

The static and dynamic coefficients of friction between the front and back surfaces of the sheet were measured under 23 ° C. and 50% RH.

(5) anti-fogging

The anti-fogging coating surface of the 7 cm wide and 7 cm long sheet specimens prepared under the same conditions was placed on a cup filled with a bath of water at a temperature of 50 ° C. After leaving for 30 minutes to evaluate the degree of frost on the sheet, if there is no water droplets on the sheet ◎, some of the water droplets are condensed ○, a lot of small water droplets △, frost if the frost on the front of the sheet was evaluated as ⅹ.

Example 1

NW LLC's PLA resin 80.0kg is melted through the main extruder and passed through the feeder block to the sheet inner layer (A), NW LLC's PLA resin 19.9kg, silica particles 0.1kg dry mixing (DRY MIXING) After melting through a sub-extruder and passed through the feeder block to the sheet surface layer (B), the polymer is discharged through a slip die, and the sheet is 300 μm thick with a B: A: B structure of 1: 8: 1. After preparing a corona discharge treatment on the sheet surface to be coated with antifoam, 1 part by weight of an antifoaming agent (Takemoto Oil Co., ELECUT-C-031-K) consisting of an amphoteric surfactant in an acrylic copolymer binder. The antifogging coating liquid mixed with 15 parts by weight of water was applied to the corona discharge-treated side using the gravure coating method. After coating, the coated solution was dried for about 15 seconds in a hot air drying process at about 75 ° C. to prepare a sheet wound in a roll form. The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 2

A sheet was prepared in the same manner as in Example 1 except that 79.0 kg of PLA resin and 1.0 kg of polybutylene succinate (PBS) were used as the sheet inner layer (A). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 3

The sheet was prepared in the same manner as in Example 1 except that 79.0 kg of PLA resin and 1.0 kg of polybutylene adipate-terephthalate (PBAT) were used as the sheet inner layer (A). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 4

The sheet was prepared in the same manner as in Example 1 except that 79.0 kg of PLA resin of N.W LLC and 1.0 kg of polylactic acid copolymer (PD-150 of DIC) were used for the inner layer (A) of the sheet. The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 5

A sheet was prepared in the same manner as in Example 1 except that 19.0 kg of PLA resin and 1.0 kg of silica particles were used for the sheet surface layer (B). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 6

NW LLC's 90.0 kg of PLA resin is melted through the main extruder and passed through the feeder block to the sheet inner layer (A). 9.95 kg of NW LLC's PLA resin and 0.05 kg of silica particles are dry mixed and melted through a sub-extruder. Except for passing through the feeder block to the sheet surface layer (B) and discharging the polymer through the slip die to produce a 300 μm thick sheet having a B: A: B structure of 0.5: 9.0: 0.5 In the same manner, a sheet was prepared. The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Example 7

NW LLC's 60.0kg of PLA resin is melted through the main extruder and passed through the feeder block to the sheet inner layer (A). NW LLC's 39.8kg of PLA resin and 0.2kg of silica particles are dry mixed and melted through the sub-extruder. Same as in Example 1 except that a 300 탆 thick sheet having a B: A: B structure of 2: 6: 2 was produced by passing the polymer through a slip die after passing it through the block to the sheet surface layer (B). To prepare a sheet. The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 1 below. In addition, the tray was molded through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 1 below.

Comparative Example 1

After melt extrusion of 100kg PLA resin of NW LLC through the main extruder and the sub-extruder, it was discharged through slip type die to manufacture a 300㎛ single layer sheet and corona discharge treatment on both sides of the sheet to be coated. One side of the sheet was coated with an anti-fog coating in the same manner as in Example 1 and dried, and the other side was coated with a gravure coating method with a coating bath solution consisting of 1 part by weight of a silicone release agent (Shin-Etsu Co., KM-9737) and 30 parts by weight of water. After drying the coating solution for about 15 seconds in a hot air drying process about 75 ℃ to prepare a sheet wound in the form of a roll. The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 2 below. In addition, the sheet was formed in a tray through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 2 below.

Comparative Example 2

Sheets were prepared in the same manner as in Example 1 except that 70.0 kg of PLA resin and 10.0 kg of polybutylene succinate (PBS) were used as the inner layer of the sheet (A). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 2 below. In addition, the sheet was formed in a tray through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 2 below.

Comparative Example 3

Sheets were prepared in the same manner as in Example 1, except that 70.0 kg of PLA resin and 10.0 kg of polybutylene adipate-terephthalate (PBAT) were used as the sheet inner layer (A). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 2 below. In addition, the sheet was formed in a tray through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 2 below.

Comparative Example 4

The sheet was prepared in the same manner as in Example 1 except that 70.0 kg of PLA resin of N.W LLC and 10.0 kg of polylactic acid copolymer (PD-150 of DIC) were used as the sheet inner layer (A). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 2 below. In addition, the sheet was formed in a tray through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 2 below.

Comparative Example 5

The sheet was prepared in the same manner as in Example 1 except that 18.5 kg of PLA resin and 1.5 kg of silica particles were used for the sheet surface layer (B). The prepared sheet was measured for transparency, flexibility, surface roughness, coefficient of friction, and antifogging. The results are shown in Table 2 below. In addition, the sheet was formed in a tray through vacuum molding, and the transparency and the anti-fogging property were measured through the molded tray. The results are also shown in Table 2 below.

Example-1 Example-2 Example-3 Example-4 Example-5 Example-6 Example-7 Furtherance
(kg) Inner layer
(A) PLA 80.0 79.0 79.0 79.0 80.0 90.0 60.0 PBS - 1.0 - - - - - PBAT - - 1.0 - - - - Polylactic acid
Copolymer - - - 1.0 - - - Surface layer
(B) PLA 19.9 19.9 19.9 19.9 19.0 9.95 39.8 Silica 0.1 0.1 0.1 0.1 1.0 0.05 0.2 coating SHEET surface - - - - - - - SHEET Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Properties SHEET Transparency (HAZE%) 1.7 2.6 4.4 1.9 2.2 1.6 1.7 SHEET Flexibility △ ○ ○ ○ △ △ △ SHEET
Surface roughness
(surface) SRa 0.014 0.017 0.014 0.015 0.052 0.010 0.013 SRz 0.515 0.509 0.499 0.519 0.882 0.482 0.503 SRmax 0.602 0.612 0.600 0.617 1.087 0.553 0.621 SHEET dynamic friction coefficient 0.52 0.50 0.53 0.51 0.42 0.60 0.54 SHEET static friction coefficient 0.37 0.35 0.38 0.38 0.20 0.45 0.39 SHEET ◎ ◎ ◎ ◎ ○ ◎ ◎ TRAY transparency
(HAZE%) 1.8 2.8 4.4 1.9 2.3 1.7 1.7 TRAY anti-fogging ○ ○ ○ ○ ○ ○ ○

Comparative Example-1 Comparative Example-2 Comparative Example-3 Comparative Example-4 Comparative Example-5 Furtherance
(kg) Inner layer
(A) PLA 80.0 70.0 70.0 70.0 80.0 PBS - 10.0 - - - PBAT - - 10.0 - - Polylactic acid
Copolymer - - - 10.0 - Surface layer
(B) PLA 20.0 19.9 19.9 19.9 18.5 Silica - 0.1 0.1 0.1 1.5 coating SHEET surface Release coating - - - - SHEET Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Anti-fog coating Properties SHEET Transparency (HAZE%) 1.5 29.5 38.0 14.8 3.5 SHEET Flexibility △ ○ ○ ○ △ SHEET
Surface roughness
(surface) SRa 0.007 0.016 0.016 0.014 0.070 SRz 0.062 0.499 0.512 0.510 1.032 SRmax 0.083 0.604 0.611 0.610 1.192 SHEET dynamic friction coefficient 0.68 0.49 0.51 0.52 0.38 SHEET static friction coefficient 0.45 0.33 0.34 0.39 0.19 SHEET △ ◎ ◎ ◎ △ TRAY transparency
(HAZE%) 1.6 30.0 38.5 14.8 3.6 TRAY anti-fogging Ⅹ ○ ○ ○ Ⅹ

Claims (13)

An inner layer (A) of a composition consisting of polylactic acid alone or a composition consisting of at least one selected from aliphatic polyesters, aromatic-aliphatic polyesters or polylactic acid copolymers excluding polylactic acid; And a multi-layered sheet designed to be composed of a surface layer (B) made of a composition comprising a release agent and a polylactic acid, The composition constituting the multilayer sheet is composed of 90.0 to 60.0 parts by weight of the inner layer (A) and 10.0 to 40.0 parts by weight of the surface layer (B) in total content; The composition constituting the inner layer (A) of the multi-layered sheet has a polylactic acid of at least 90.0 parts by weight, and the sum of aliphatic polyesters, aromatic-aliphatic polyesters or polylactic acid copolymers other than polylactic acid is 10.0 parts by weight or less. And; An acrylic resin is used as a binder on one side of the multilayer sheet, and a quaternary ammonium salt, alkylsulfate, alkylsulfonate, alkylphosphonate, and amphoteric system is used. A biodegradable multilayer sheet having excellent antifogging property and releasability, characterized in that the antifogging coating layer comprising one or more surfactants is formed at 0.01 to 1.00 g / m 2. delete delete The anti-fogging property and mold release property according to claim 1, wherein the composition constituting the surface layer (B) of the multi-layered sheet is 95.0 to 99.5 parts by weight of polylactic acid and 0.5 to 5.0 parts by weight of a release agent. This excellent biodegradable multilayer sheet. According to claim 1, wherein the polylactic acid is composed of L-lactic acid, D-lactic acid or L, D-lactic acid, the number average molecular weight is 10,000 or more antifogging properties characterized in that these polylactic acid is used alone or in combination Biodegradable multilayer sheet with excellent release property. The method of claim 1, wherein the aliphatic polyester is selected from dicarboxylic acids or derivatives of the structure ROOC- (CH ₂ ) n-COOR '(R, R' is hydrogen or an alkyl group, n is an integer of 2 to 14) structure Glycols consist of diols or polyalkylene glycols of the structure HO- (CH ₂ ) n-OH (n is an integer of 2 or more) or aliphatic dihydric alcohols of the structure represented by the following general formula (1). Biodegradable multilayer sheet excellent in antifogging property and releasability, characterized in that the group is used; General formula (1)

R ₁ in the general formula (1) is an alkylene group of C ₂ ~ C _8, R ₂ is an alkyl group of C ₂ ~ C _8. The aliphatic component of claim 1, wherein the aromatic-aliphatic polyester is an aromatic component and is at least one selected from dicarboxylic acids having a structure of ROOC-Ar-COOR '(R, R' is hydrogen or an alkyl group) or derivatives thereof. Wherein at least one member selected from dicarboxylic acids or derivatives thereof having a structure of ROOC- (CH ₂ ) n -COOR '(R, R' is hydrogen or an alkyl group, n is an integer of 2 to 14), and glycols are selected from HO- (CH ₂₎ n-OH anti-fogging performance, it characterized in that the group is aliphatic in structure consisting of an alcohol represented by (n is 2 or more integer) diol or poly (alkylene glycol) or the following general formula (1) of the structure to be used Biodegradable multilayer sheet having excellent release property; General formula (1)

R ₁ in the general formula (1) is an alkylene group of C ₂ ~ C _8, R ₂ is an alkyl group of C ₂ ~ C _8. The polylactic acid copolymer according to claim 1, wherein the polylactic acid copolymer is a composition consisting of a unit consisting of dicarboxylic acid or derivatives thereof and a unit consisting of aliphatic glycols, and examples of dicarboxylic acid or derivatives thereof include L-lactic acid and D-lactic acid. or L, D- lactic _{acid, ROOC (CH 2) nCOOR '} (R, R' is hydrogen or an alkyl group, n is an integer of 2 to 14) having a succinic acid structure, glutaric acid, malonic acid, oxalic acid, adipic acid, sebacic Dicarboxylic acids or derivatives thereof having the structure of nitric acid, azelaic acid, nonanedicarboxylic acid and their alkyl or aryl ester derivatives, and ROOC-Ar-COOR '(where R and R' are hydrogen or alkyl groups), terephthalic acid, phthalic acid, iso Phthalic acid, naphthalene 2,6-dicarboxylic acid, diphenylsulfonic acid dicarboxylic acid, diphenylmethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, cyclohexanedicarboxylic acid Acid or alkylene esters thereof selected from the group Aliphatic glycols are ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentane having a structure of HO- (CH ₂ ) n-OH (n is an integer of 2 or more). Alkylene glycol or polyalkylene glycol composed of diol, 1,6-hexanediol or propylene glycol, 1,4-cyclohexanediol, hexamethylene glycol, polyethylene glycol, triethylene glycol, neopentyl glycol and tetramethylene glycol A biodegradable multilayer sheet having excellent antifogging property and releasability, characterized in that a group consisting of an aliphatic dihydric alcohol capable of forming a branched structure represented by the group consisting of the following general formula (1); General formula (1)

R ₁ in the general formula (1) is an alkylene group of C ₂ ~ C _8, R ₂ is an alkyl group of C ₂ ~ C _8. The method of claim 1, wherein the release agent is silica, silica gel, colloidal silica, wet silica, silicon oxide such as dry silica, titanium oxide, calcium carbide, kaolin, kaolinite, clay, talc, alumina, alumina sol, zeolite, graphite Inorganic particles such as zirconium sol, feldspar, molybdenum disulfide, carbon black, barium salt, barium sulfate, antimony oxide, calcium silicate, aluminum silicate, calcium sterate and polystyrene, polymethyl methacrylate, methyl methacrylate Copolymer, methyl methacrylate copolymer, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguamine-formaldehyde condensate, benzoguanamine resin, melamine-formaldehyde condensate, benzoguamine -Melamine-formaldehyde condensate, crosslinked silicone resin, silicone resin, gelatin Biodegradable multilayer sheet excellent in antifogging property and releasability, characterized in that at least one selected from organic particles such as starch. delete delete delete Biodegradable anti-fogging tray, characterized in that molded into a biodegradable multi-layer sheet excellent in anti-fogging property and releasability of claim 1.