KR102050279B1 - The method for manufacturing multi-layer sheet of polylactic acid - Google Patents

Abstract

In order to solve the low impact resistance and heat resistance of the existing polylactic acid-based single layer sheet, the sheet is made of a multilayer and the outer layer and the inner layer are composed of a specific composition. The present invention relates to a method for producing a polylactic acid multilayer sheet for flat plates provided with blocking properties, wherein the polylactic acid multilayer sheet for flat plates according to the present invention is made of polylactic acid, and the outer layer (B) of the sheet is made of polylactic acid. Three layers (B / A) consisting of a mixture of lactic acid and polymethyl methacrylate (PMMA) homopolymer or copolymer and at least one polymethyl methacrylate, acrylic resin, and slip or anti-blocking agent / B) structured.
The flat polylactic acid multilayer sheet of the present invention configured as described above is a flat PLA-based multilayer sheet having improved heat resistance and impact resistance compared to the conventional PLA sheet, and has proper transparency and surface characteristics for processing as a flat sheet. It also has excellent commercial value with slip and anti-blocking properties on the sheet surface.

Description

The method for manufacturing multi-layer sheet of polylactic acid}

The present invention relates to a method for producing a polylactic acid multilayer sheet for flat plates, and more particularly, in order to solve the low impact resistance and heat resistance of a conventional polylactic acid monolayer sheet, the sheet is made into a multilayer and the outer layer and the inner layer are composed of a specific composition. A method for producing a polylactic acid multilayer sheet for flat plates which has provided slip properties and anti-blocking properties of sheet surface layers suitable for blister and packaging box applications.

In general, synthetic plastics have been used for various purposes all over the world as packaging materials that are indispensable to modern people because of their cheap and light properties along with their excellent 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 cannot 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 inexpensively manufactured in large quantities by developing fermentation method of L-lactic acid. In composting conditions, the decomposition rate is fast, and it has excellent characteristics such as resistance to mold and exploitation resistance to food, and thus the range of its application field is expanding. At present, various attempts have been made to give PLA suitable properties for each country.

Among these fields, the sheet (SHEET) manufactured by melt extruding PLA is a situation where the application speed is very fast, but it is not equipped with various functionalities, and thus cannot be widely commercialized. Among the functionalities for increasing the commercialization of PLA sheet is the flexibility and surface properties of the sheet. Flat sheets used in various blisters and packing boxes require processes such as printing, cutting, folding, etc. in order to be a final finished product, and these processes require flexibility, heat resistance, slip between sheets and anti-blocking ( Anti-Blocking property is required. Conventional techniques for imparting flexibility of the PLA sheet have been introduced in various ways, but mainly using a method of applying an aliphatic polyester. However, in the case of aliphatic polyester, when mixed with polylactic acid, the content that can be mixed is limited due to the problem of impairing transparency, and the content of aliphatic polyester that is added in a small amount is expected to expect the flexibility required by the flat sheet. Is difficult. In addition, polylactic acid has a limited use due to its low heat resistance. In particular, in the case of a blister and a packaging box made of only plain PLA, there is a problem that deformation occurs at a temperature higher than room temperature. In general, techniques for improving the heat resistance of PLA include a method of improving the heat resistance by adding an inorganic filler or a crystal nucleating agent, a method of mixing aliphatic polyester, a method of improving the degree of crystallinity and imparting heat resistance. Examples of such techniques include patents for improving heat resistance by mixing calcium carbonate and boron nitride with crystal nucleating agents as inorganic fillers in the blend of PHB and PLA of Mitsubishi Gas Chemical of Japan (Japanese Patent Laid-Open Publication No. 2000-239508), Mitsui Corporation Patent that adds plasticizer to impart flexibility along with 10 to 50 wt% in aliphatic polyester resin having melting point of 80 to 250 ° C in order to impart heat resistance to PLA (Japanese Patent Laid-Open No. 1999-241008), Shiseido Patent to improve the heat resistance by adding polybutylene succinate resin to 10 to 90% content of PLA (Japanese Patent Laid-Open No. 2001-039426), increasing the degree of crystallinity when manufacturing PLA films, sheets of Japan Nippon Inks And Japanese Patent Laid-Open Patent Publication No. 1996-073628. However, these technologies are not clear in the heat resistance improvement technique, or require a process such as annealing treatment or stretching orientation in the manufacturing process, and the transparency of the sheet is limited. In the case of slip between sheets and anti-blocking properties, there are generally a coating method and an impregnation method using a master batch chip, and a coating method is mainly applied. In the impregnation method using a master batch chip, slip and anti-blocking agents are designed and applied only to synthetic resins that are melt-extruded at a relatively low temperature due to carbonization during the melt extrusion process. In the case of PLA sheet, a slip and anti-blocking agent suitable for PLA has not yet been designed. However, in the case of the coating method, due to the low heat resistance of the PLA sheet can not give a sufficient drying temperature, there is a problem that the stability of the coating film is weak, compared to the impregnation method using a master batch chip in terms of production cost. As a technique for imparting sheet slip and anti-blocking properties to general synthetic resin sheets, Japanese Patent Laid-Open No. 5-239424 describes silica alumina particles having a diameter of 0.01-5 microns in a polyester resin containing isophthalic acid. Discloses a polyester resin composition for producing a thermoforming sheet to which 0.1-0.5 parts by weight of a catalyst is added. Japanese Patent Laid-Open No. 3-95779 discloses a coating liquid containing reactive ethyl silicate and 2-40 wt% of thermosetting dimethylpolysiloxane. A sheet in which an active layer of silicon oxide is formed by coating a polyester film is disclosed, and Japanese Patent Application Laid-open No. Hei 7-85631 discloses activity with a coating layer containing a partial hydrolyzate of polysilic acid, a silicone resin, and a surfactant. Disclosed is a polyester sheet to be provided. In addition, U.S. Patent Nos. 5,110,671 and 4,961,992 disclose that silicone oil is used to improve activity. Korean Patent Registration No. 0665770 discloses that inorganic particles are dispersed in a skin layer of an amorphous polyester sheet. A method of coating a slip agent on a skin layer is disclosed.

However, the above-mentioned conventional patents are mostly applied to a sheet of general synthetic resin, and by coating method, it is not easy to apply these techniques to polylactic acid sheet as it is, when applying the above method to polylactic acid sheet Due to the transparency problem of the sheet or the low heat resistance of the polylactic acid, there is a problem in that the coating is poor in drying and cannot be used industrially.

Patent Document 1: Japanese Patent Laid-Open No. 2000-239508 Patent Document 2: Japanese Patent Laid-Open Publication 1999-241008 Patent Document 3: Japanese Patent Laid-Open No. 2001-039426 Patent Document 4: Japanese Patent Application Laid-Open No. 1996-073628 Patent Document 5: Japanese Patent Application Laid-Open No. 5-239424 Patent Document 6: Japanese Patent Application Laid-open No. Hei 3-95779 Patent Document 7: Japanese Patent Application Laid-open No. Hei 7-85631 Patent Document 8: US Patent No. 5,110,671 Patent Document 9: US Patent No. 4,961,992 Patent Document 10: Republic of Korea Patent Registration No. 0665770

Accordingly, the present invention has been made in view of the above technical problems in the prior art, and the main purpose of the present invention is to provide slip and / or anti- In order to provide an eco-friendly biodegradable multilayer sheet capable of retaining blocking properties, the inner layer is composed of polylactic acid, and the outer layer is a combination of polymethyl methacrylate (PMMA) resin and acrylic resin. It is to provide a polylactic acid multi-layer sheet for flat plates that can provide better impact resistance and heat resistance than PLA-based single-layer sheet within a range that does not significantly decrease.

Another object of the present invention is to provide an easier method of manufacturing a polylactic acid multilayer sheet for flat plates having the above excellent characteristics.

The present invention may also be directed to achieving other objects in addition to the above-described specific objects that may be readily derived by one of ordinary skill in the art from the general description of this specification.

Flat polylactic acid multilayer sheet of the present invention for achieving the above object;

The inner layer (A) of the sheet is made of polylactic acid, and the outer layer (B) of the sheet is slipped with at least one polymethylmethacrylate and acrylic resin selected from polylactic acid and polymethyl methacrylate (PMMA) homopolymer or copolymer. The anti-blocking agent or the anti-blocking agent is characterized in that the three-layer (B / A / B) structure consisting of a mixture.

According to another configuration of the present invention, the content of polylactic acid in the total content of the outer layer (B) is 10.0 to 25.0 parts by weight, at least one polymethyl methacrylate selected from polymethyl methacrylate (PMMA) homopolymer or copolymer The content of the rate is 50.0 to 80.0 parts by weight, the content of the acrylic resin is characterized in that 10.0 to 25.0 parts by weight.

According to another configuration of the present invention, the slip or anti-blocking agent in the total content of the outer layer (B) is characterized in that it is composed of 0.1 to 8.0 parts by weight.

According to another configuration of the invention, the layer ratio of the three-layer (B / A / B) structure is characterized in that 0.5 / 9.0 / 0.5 to 2.0 / 6.0 / 2.0.

According to another configuration of the present invention, 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, characterized in that they are used alone or in combination.

According to another configuration of the present invention, the polymethyl methacrylate (PMMA) homopolymer or copolymer selected from one or more polymethyl methacrylate resin has a melt index (MI) value of 4.0 to 8.0g / 10min (at Methyl methacrylate homopolymer (190 ° C./2.16 K) or a copolymer of methyl methacrylate and at least one comonomer selected from methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and styrene It features.

According to another configuration of the present invention, the acrylic resin is a single or copolymer containing a styrene or butadiene rubber component in at least one compound selected from the group consisting of alkyl methacrylate compounds and alkyl acrylate compounds. It is done.

According to another configuration of the present invention, the slip agent is an organopolysiloxane compound linearly or crosslinked with a silicone compound such as silicone oil, silicone rubber and silicone resin, or used as a higher fatty acid wax such as polyethylene wax and polypropylene wax. It is characterized by.

According to another aspect of the present invention, the anti-blocking agent is a 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 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, gelatin, Min in characterized in that the selected organic particles used.

According to another configuration of the invention, the thickness of the sheet is characterized in that 0.15 to 1.20mm.

The polylactic acid multilayer sheet for flat plates of the present invention configured as described above is a flat PLA-based multilayer sheet having improved heat resistance and impact resistance compared to a conventional PLA sheet, and has proper transparency and surface characteristics for processing as a flat sheet. In addition, it has excellent commercial value with slip and anti-blocking properties on the sheet surface layer.

Hereinafter, the present invention will be described in more detail by preferred embodiments, but it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such variations and modifications belong to the appended claims. will be.

According to a preferred embodiment of the present invention, the polylactic acid (PLA) used according to the present invention is obtained by polymerizing lactic acid. In the case of the polylactic acid used in the present invention, L-lactic acid, D-lactic acid or L, D-lactic acid, the number average molecular weight is preferably 10,000 or more. These polylactic acids may be used alone or in combination.

In addition, the PMMA resin according to the present invention is a methyl methacrylate homopolymer or methyl methacrylate and methyl acrylate, methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene of any one or more comonomers selected from styrene Copolymers can be used. The acrylic impact resistant agent may be used alone or in a copolymer containing a styrene or butadiene rubber component in at least one compound selected from the group consisting of alkyl methacrylate compounds and alkyl acrylate compounds. In addition, the material used for imparting slip properties may be an organic polysiloxane compound that is linear or crosslinked with a silicone compound such as silicone oil, silicone rubber and silicone resin, or higher fatty acid wax such as polyethylene wax or polypropylene wax may be used. have.

According to another embodiment of the invention, the materials used for imparting anti-blocking properties according to the invention are silicon oxides such as silica, silica gel, colloidal silica, wet silica, dry silica, titanium oxide, calcium carbide, kaolin, Kaolinite, clay, talc, alumina, alumina sol, zeolite, graphite, zirconium sol, feldspar, molybdenum disulfide, carbon black, barium salt, barium sulfate, antimony oxide sol, calcium silicate, aluminum silicate, calcium stearate Inorganic particles and polystyrene, polymethyl methacrylate, methyl methacrylate copolymer, methyl methacrylate copolymer crosslinked product, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguamine-formaldehyde condensate, Benzoguanamine resin, melamine-formaldehyde condensate, benzoguamine-melamine-formal Organic particles such as hydroxyl condensate, crosslinked silicone resin, gelatin, starch may be used.

PLA-based multilayer sheet for a plate excellent in impact resistance and heat resistance proposed in the present invention is composed of an outer layer / inner layer / outer layer (B / A / B) structure, the outer layer / inner layer / outer layer ratio of 0.5 / 9.0 / 0.5 to It is preferable that it consists of 2.0 / 6.0 / 2.0. At this time, in order to exhibit sufficient impact resistance and heat resistance, the thickness of the outer layer of the sheet is also an important factor, the outer layer (B) thickness should be maintained at 10㎛ or more, preferably 30㎛ level is appropriate. In the case of generally used sheets, considering that the thickness is about 300 μm, the outer layer / inner layer / outer layer should be designed to 1.0 / 8.0 / 1.0 for the layer ratio of the outer layer (B) to have a thickness of 30 μm. The higher the outer layer (B) thickness, the stronger the impact resistance and heat resistance, but when the thickness of the outer layer (B) is 50 µm or more, no significant impact resistance and heat resistance synergistic effect is obtained. The thickness of the PLA-based multilayer sheet in the present invention is 300㎛ when the layer ratio is 0.5 / 9.0 / 0.5 to 2.0 / 6.0 / 2.0 thickness of the outer layer (B) is 15 to 60 ㎛ level. The composition of the raw material applied to the outer layer (B) is 50.0 to 80.0 parts by weight of the PMMA resin to enhance the heat resistance in terms of the weight of the outer layer (B) of the sheet, and the acrylic resin to strengthen the impact resistance is 10.0 To 25.0 parts by weight, PLA resin should be made of 10.0 to 25.0 parts by weight. When more than 80.0 parts by weight of PMMA-based resin is added to the acrylic resin and PLA resin content decreases the impact resistance is worse, if less than 50.0 parts by weight of the heat resistance strengthening effect is lost. In particular, in the process of mixing the PMMA resin, acrylic resin, PLA resin in the extruder, the content of the PMMA resin is reduced, it was confirmed that the heat resistance strengthening effect of the PMMA resin is significantly reduced. Even in the case of acrylic resin, at 25.0 parts by weight or more, the transparency of the sheet is sharply deteriorated, making it difficult to apply to a field requiring transparency, and when it is added at 10.0 parts by weight or less, the effect of strengthening impact resistance is not seen. In general, the PMMA resin, acrylic resin, and PLA resin added to the outer layer of the sheet may be added to the extruder as raw materials, but in the present invention, in order to increase the dispersibility of the acrylic resin, the PLA and the acrylic resin are first 1: 1. The mixture was put into an extruder. In addition, M.I. (Melt Index, at 190 ° C./2.16K) of the PMMA resin used in the present PLA-based multilayer sheet is important and should be 4 to 8 g / 10 min. If the M.I. value of the PMMA resin is out of this range, the difference in the extrusion temperature conditions of PLA and PMMA increases, and streaks may occur on the sheet surface during sheet forming, which is not preferable. In order to suit the use of the sheet to the use of blisters and packaging boxes, it must be a flat sheet, in which case the outer layer (B) of the sheet should be added with a slippery and / or anti-blocking property. In the total content of the outer layer (B), the sum of the PMMA resin, the acrylic resin, and the PLA resin is 92.0 to 99.9 parts by weight, the slippering material and / or the anti-blocking property imparting material should be controlled to 8.0 to 0.1 part by weight. In the case of a slip-providing substance, it is important to select an appropriate content because it causes slippage between sheets to improve workability in the printing process of sheets. In the case of a slip imparting material, it should be kept at 3.0 parts by weight or less based on the outer layer (B) of the sheet. If it is more than 3.0 parts by weight, there is a difficulty in carrying and stacking the sheet due to excessive slippage property, and in a high temperature and high humidity environment, it may cause a poor appearance of the sheet, a decrease in transparency and printability. In addition, the slip property is related to the anti-blocking property, and when a sufficient anti-blocking property imparting material is put into the sheet outer layer, the slip property of the sheet is exhibited even without the slip imparting material. Therefore, the slipping imparting material is most preferably 1.0 parts by weight or less when added to the outer layer (B) of the sheet simultaneously with the anti-blocking property imparting material. In the case of the anti-blocking property imparting material, it should be maintained at 5.0 to 0.5 parts by weight based on the outer layer (B) of the sheet. In the case of the anti-blocking material imparting agent serves to prevent the adhesion between the sheets, when applied excessively, it may undermine the transparency of the sheet. Preferably 3.0 to 0.5 parts by weight is the best. In addition, since the anti-blocking properties imparting material affects the anti-blocking performance of the sheet and the occurrence of scratches according to the particle size, selection of particles having a diameter of 1.0 to 10.0 μm, preferably a diameter of 2.0 to 6.0 μm is important. Do.

PLA-based multilayer sheet composition of the B / A / B structure according to the present invention as described above is melt extruded from each extruder (EXTRUDER) is divided into layers in the feeder block is formed by melt extrusion into a die (DIE) In this case, the most important is the temperature condition and the processing is preferably performed in a temperature range of 180 to 250 ° C, preferably in a temperature range of 200 to 230 ° C. This is because the thermal decomposition of the resin composition is minimized, which does not harm the physical properties of the sheet composition, and it is most suitable for controlling the flow of the molten polymer discharged from the die by maintaining a sufficient melting temperature.

The present invention will be described in more detail by the following examples and comparative examples, but the scope of the present invention is not limited to these examples. The test was performed under various conditions by the following method to determine whether the sheet produced in the following Examples and Comparative Examples had sheet properties that can satisfy the heat resistance and transparency.

(1) heat resistance

After leaving the specimen with a thickness of 0.20 mm for 3 days in a constant temperature and humidity chamber at a temperature of 60 ° C. and a humidity of 50%, no deformation occurred ○, a slight distortion occurred △, an extremely severe deformation Marked with ×.

(2) impact resistance

Impact resistance was measured by a film impact tester (FILM IMPACT TESTER) of "TOYO SEIKI SEISAKU-SHO", and the impact strength was expressed by the following formula.

Impact strength (kN.m / mm) = force required to destroy the specimen (kg.cm) / specimen thickness (mm) X 0.09807

(3) transparency

A sample of 10 cm x 10 cm sample was placed vertically in an HAMATIC DIGITAL HAZEMETER (manufactured by Nippon Densoku Co., Ltd.) vertically, 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.

[Equation 1] haze (%) = (1- amount of scattered light / total transmission amount of light) × 100

(4) Surface Roughness (DIN-4768)

The surface and the back of the sheet were measured by a contact method using a 5 micrometer R needle with a measuring length of 2.5 mm, 40 scanning heads 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.

(5) Friction Coefficient (ASTM D 1904)

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

Example 1

90kg of PLA resin (NW LLC PLA-2003D) is put into the extruder No. 1 and melted, and then passed through the feeder block to the inner layer (A) of the sheet, and 7kg of PMMA resin, PLA resin and acrylic resin 0.05 kg of silicon (Silicone) and 0.1 kg of silica particles were added to the extruder No. 2 after DRY MIXING and melted after passing through the feeder block to the outer layer (B). Then, the polymer was discharged through a slip die to prepare a PLA-based multilayer sheet having a thickness of 300 μm with a B / A / B structure of 0.5: 9.0: 0.5. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Example 2

80kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet, and 14kg of PMMA resin, PLA resin and acrylic resin were 1: 1. 0.1 kg of silicon and 0.2 kg of silica particles were mixed with 6 kg of the mixed raw material, and then mixed and melted in an extruder No. 2, passed through the feeder block to the outer layer (B) of the sheet, and then the polymer was discharged through the slip die 1.0: A 300-micrometer thick PLA-based multilayer sheet having a B / A / B structure of 8.0: 1.0 was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Example 3

60kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet. 28 kg of PMMA resin, PLA resin and acrylic resin were 1: 1. 0.2 kg of silicon and 0.4 kg of silica particles were mixed with 12 kg of the mixed raw material, and then mixed with the extruder No. 2, melted, passed through the feeder block to the outer layer B of the sheet, and the polymer was discharged through a slip die. A 300-micrometer thick PLA-based multilayer sheet having a B / A / B structure of 6.0: 2.0 was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Example 4

80kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet, and 14kg of PMMA resin, PLA resin and acrylic resin were 1: 1. After drying and mixing 0.6kg of silica particles into 6kg of mixed raw materials, the mixture was put into an extruder No. 2, melted, passed through the feeder block to the outer layer B of the sheet, and the polymer was discharged through a slip die to obtain 1.0: 8.0: 1.0 A 300-micrometer thick PLA-based multilayer sheet having a B / A / B structure was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Comparative Example 1

80 kg of PLA resin (NW LLC PLA-2003D) is put into the extruder No. 1, melted and passed through the feeder block to the inner layer (A) of the sheet, and 20 kg of PLA resin (NW LLC PLA-2003D) is extruded twice. After passing through the feeder block through the feeder block to the outer layer (B), the polymer is discharged through the slip die to obtain a 300 μm thick PLA single layer sheet having an A / A / A structure of 1.0: 8.0: 1.0. Prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Comparative Example 2

50 kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet. 35 kg of PMMA resin, PLA resin and acrylic resin were 1: 1. 2.5 kg of silicon and 1.5 kg of silica particles were mixed with 15 kg of the mixed raw material, mixed with the extruder No. 2, melted, passed through the feeder block to the outer layer B of the sheet, and the polymer was discharged through a slip die 2.5: A 300-micrometer-thick PLA-based multilayer sheet having a B / A / B structure of 5.0: 2.5 was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Comparative Example 3

80kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet. 8 kg of PMMA resin, PLA resin and acrylic resin were 1: 1. 0.05 kg of silicon and 0.10 kg of silica particles were mixed with 12 kg of the mixed raw material, and then mixed with the extruder No. 2, melted, passed through the feeder block to the outer layer B of the sheet, and the polymer was discharged through the slip die 1.0: A 300-micrometer thick PLA-based multilayer sheet having a B / A / B structure of 8.0: 1.0 was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Comparative Example 4

80kg of PLA resin (NW LLC PLA-2003D) was put into the extruder No. 1 and melted, and passed through the feeder block to the inner layer (A) of the sheet, and 18kg of PMMA resin, PLA resin and acrylic resin were 1: 1. 0.5 kg of silicon and 1.0 kg of silica particles were mixed with 2 kg of the mixed raw materials, and then mixed with the extruder No. 2, melted, passed through the feeder block to the outer layer B of the sheet, and the polymer was discharged through the slip die 1.0: A 300-micrometer thick PLA-based multilayer sheet having a B / A / B structure of 8.0: 1.0 was prepared. The specimens were fabricated from the prepared PLA-based multilayer sheets to measure heat resistance, impact resistance, transparency, surface roughness, and coefficient of friction. The results are shown in Table 1 below.

Example-1 Example-2 Example-3 Example-4 Comparative Example-1 Comparative Example-2 Comparative Example-3 Comparative Example-4 Furtherance Inner layer
(A) PLA-2003D 90 kg 80 kg 60 kg 80 kg 80 kg 50 kg 80 kg 80 kg Outer layer
(B) PMM-based resin 7 kg 14 kg 28 kg 14 kg - 35 kg 8 kg 18 kg Arc-based resin 1.5 kg 3 kg 6 kg 3 kg - 7.5kg 6 kg 1 kg PLA-2003D 1.5 kg 3 kg 6 kg 3 kg 20 kg 7.5kg 6 kg 1 kg Silicone 0.05kg 0.1kg 0.2 kg - - 2.5kg 0.05kg 0.5kg Silica 0.10kg 0.2 kg 0.4kg 0.6kg - 1.5 kg 0.10kg 1.0 kg Floor ratio Outer layer / inner layer / outer layer 0.5 / 9.0 / 0.5 1.0 / 8.0 / 1.0 2.0 / 6.0 / 2.0 1.0 / 8.0 / 1.0 fault 2.5 / 5.0 / 2.5 1.0 / 8.0 / 1.0 1.0 / 8.0 / 1.0 Properties Heat resistance △ ○ ○ △ × ○ × ○ Impact strength
(kN.m / mm) 2.2 2.6 3.2 2.6 1.8 3.9 3.4 1.9 Transparency (HAZE%) 2.1 3.3 4.3 4.2 1.5 11.7 3.9 9.7 surface
Roughness
(surface) SRa 0.012 0.019 0.018 0.023 0.008 0.031 0.009 0.033 SRz 0.510 0.515 0.537 0.595 0.031 0.789 0.239 0.892 SRmax 0.608 0.701 0.720 0.740 0.082 1.109 0.322 1.209 surface
Roughness
(Back side) SRa 0.047 0.049 0.049 0.051 0.009 0.098 0.014 0.102 SRz 0.959 0.990 0.987 0.991 0.043 1.782 0.308 1.792 SRmax 1.113 1.119 1.108 1.177 0.089 2.350 0.446 2.225 Dynamic friction coefficient 0.51 0.47 0.47 0.67 cohesion 0.09 0.87 0.08 Static friction coefficient 0.34 0.31 0.30 0.43 cohesion 0.08 0.79 0.08

Claims (10)

In the method for producing a flat sheet polylactic acid multilayer sheet consisting of a polylactic acid and a three-layer structure of two outer layers (B) and one inner layer (A),
Injecting the polylactic acid into the extruder No. 1 and melting the polylactic acid to pass through the feeder block to the inner layer A of the sheet;
To achieve the outer layer (B), the content of polylactic acid is 10.0 to 25.0 parts by weight, the content of polymethyl methacrylate (PMMA) resin is 50.0 to 80.0 parts by weight, and the content of acrylic resin is 10.0 to 25.0 parts by weight, First, a polylactic acid and an acrylic resin are mixed 1: 1, and then a polymethyl methacrylate (PMMA) resin is mixed, wherein the melt index of the polymethyl methacrylate (PMMA) resin is 4.0. To 8.0 g / 10 min (at 190 ° C.);
With respect to the raw material of the outer layer (B) in which the polylactic acid, polymethyl methacrylate (PMMA) resin and acrylic resin are mixed, a slip agent and / or an anti-blocking agent may be further mixed, but the outer layer ( 92.0 to 99.9 parts by weight of polylactic acid, polymethyl methacrylate (PMMA) resin and acrylic resin in the total content of B), and 0.1 to 8.0 parts by weight of slip and / or anti-blocking agent. In the case where both the slip agent and the anti-blocking agent are mixed, the slip agent is 0.1 to 3.0 parts by weight in the total content of the outer layer (B), and the anti-blocking agent is 0.5 to 5.0 parts by weight of dry mixing (Dry-Mixing) process;
Putting the dry mixed outer layer (B) raw material into an extruder No. 2 and melting the raw material to pass through the feeder block to the outer layer (B) of the sheet;
By discharging a polymer through a slip die, the layer ratio of the three-layer (B / A / B) structure is 0.5 / 9.0 / 0.5 to 2.0 / 6.0 / 2.0, and the thickness of the outer layer (B) is 15 to 60 μm. To be, wherein the method for producing a polylactic acid multilayer sheet for a flat plate, characterized in that consisting of a process of melt-extrusion at a temperature of 180 to 250 ℃.
delete delete delete The polylactic acid for flat plates according to claim 1, wherein the polylactic acid is composed of L-lactic acid, D-lactic acid, or L, D-lactic acid, and has a number average molecular weight of 10,000 or more. Method for producing a multilayer sheet.
The method of claim 1, wherein the polymethyl methacrylate (PMMA) homopolymer or copolymer selected from one or more polymethyl methacrylate resin is methyl methacrylate homopolymer or methyl methacrylate and methyl acrylate, ethyl ( It is a copolymer of any one or more comonomers chosen from a meta) acrylate, a butyl (meth) acrylate, and styrene.
2. The flat plate according to claim 1, wherein the acrylic resin is a single or copolymer containing a styrene or butadiene rubber component in at least one compound selected from the group consisting of alkyl methacrylate compounds and alkyl acrylate compounds. Method for producing a polylactic acid multilayer sheet for use.
The method of claim 1, wherein the slip agent is an organopolysiloxane compound linear or crosslinked with any compound selected from silicone oil, silicone rubber and silicone resin, or is used as a higher fatty acid wax of polyethylene wax or polypropylene wax. The manufacturing method of the polylactic acid multilayer sheet for flats.
The method of claim 1, wherein the anti-blocking agent is selected from silica, silica gel, colloidal silica, wet silica, dry silica, silicon oxide, titanium oxide, calcium carbide, kaolin, kaolinite, clay, talc, alumina, alumina sol, zeolite, Inorganic particles selected from graphite, zirconium sol, feldspar, molybdenum disulfide, carbon black, barium salt, barium sulfate, antimony oxide, calcium silicate, aluminum silicate, calcium sterate, polystyrene, polymethyl methacrylate, methyl methacrylate Acrylate copolymer, methyl methacrylate copolymer, polytetrafluoroethylene, polyvinylidene fluoride, polyacrylonitrile, benzoguamine-formaldehyde condensate, benzoguanamine resin, melamine-formaldehyde condensate, benzogu Amine-Melamine-Formaldehyde Condensate, Crosslinked Silicone Resin, Gelatin A method for producing a polylactic acid multilayer sheet for a flat plate, characterized in that organic particles selected from starch are used.
10. The method according to any one of claims 1 to 5, wherein the thickness of the sheet is 0.15 to 1.20 mm.