KR102102303B1 - Biodegredable sheet composition emitting far infraredray and having excellent transparency and heat resistance, and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a biodegradable sheet composition having improved heat resistance and transparency, and to a manufacturing method thereof, wherein the composition is composed of a material which is biodegradable by microorganisms, has improved heat resistance and transparency, and contains a hydrophilic agent in an outer layer thereof to improve non-fogging properties. The biodegradable sheet composition of the present invention comprises: an inner layer including 79-89.6 wt% of polylactic acid, 1-5 wt% of polybutylene adipate-co-terephthalate, 9-15 wt% of talc, 0.2-0.6 wt% of ethylene bis(stearamide), 0.1-0.3 wt% of a first antioxidant, and 0.1-0.3 wt% of a second antioxidant with respect to 100 wt% of the whole inner layer; and an outer layer integrally stacked on an upper surface of the inner layer, and including 90-97 wt% of polylactic acid and 3-10 wt% of an hydrophilic agent with respect to 100 wt% of the whole outer layer.

Description

Biodegradable sheet composition with improved heat resistance and transparency and its manufacturing method {BIODEGREDABLE SHEET COMPOSITION EMITTING FAR INFRAREDRAY AND HAVING EXCELLENT TRANSPARENCY AND HEAT RESISTANCE, AND MANUFACTURING METHOD THEREOF}

The present invention relates to a biodegradable sheet composition having improved heat resistance and transparency, and a method for manufacturing the same, in particular, it is composed of a material capable of biodegrading by microorganisms, and improves heat resistance and transparency, and also contains a hydrophilic agent in the outer layer. The present invention relates to a biodegradable sheet composition having improved heat resistance and transparency to improve antifogging properties and a method for manufacturing the same.

In general, food packaging containers are demanding high-performance, high-quality products due to the increase in consumer's national income and changes in food hygiene, and rapid changes in climate and seasonal factors such as global warming and consumer food preferences. With the diversification of ready-to-eat processed foods and the characteristics of packaging objects such as fruit fish and meat, the packaging method and demand pattern of various foods are rapidly changing.

According to the changes in the food packaging method and the demand pattern, the food packaging container goes beyond the concept of simple packaging for the conventional food and supplies the fresh food through the increase in the freshness retention period of the food and responds to the characteristics of the packaged object. It is equipped with functionalities such as antibacterial, deodorizing, and antioxidant for reducing waste, securing heat resistance for instant food cooking and packaging of high-temperature food, and reducing environmental pollution caused by disposal of packaging containers. It is urgently required to develop a food packaging container that secures heat resistance for food packaging, and has eco-friendliness when disposing of the packaging container.

And as a prior art related to a packaging material having antimicrobial properties for the packaging of food, Korean Patent Publication No. 10-2017-0026274 (2017. 03. 09. published) "Natural extract introduced inorganic mineral antibacterial composition and Packaging materials using the same and a method of manufacturing the same, “Surface and pore structure of any inorganic mineral selected from natural minerals including illite, ore and skorea, and synthetic minerals containing hydrotalcite” Nano-processing to finely improve at the nanometer level; Preparing an antimicrobial composition by mixing the inorganic mineral powder treated in the nano-treatment step and a natural extract solution having antibacterial properties extracted from plants in the same weight ratio and freeze-drying; And preparing a water-soluble antibacterial coating agent using the antibacterial composition prepared in the step of preparing the antibacterial composition and an aqueous polyurethane resin, and coating the prepared water-soluble antibacterial coating agent on a base film. And packaging method manufacturing method using the same ”is disclosed,

Next, as a prior art related to a packaging container having a deodorizing property for food packaging, a method of manufacturing a kimchi storage container having an acetic acid removal function in Korean Patent Registration No. 10-1705604 (announced on February 6, 2017) As described in "A step of mixing 10 to 20% by weight of sodium hydrogen carbonate and 80 to 90% by weight of polyethylene to obtain a masterbatch mixture; Obtaining a masterbatch by extruding while maintaining the masterbatch mixture at 100 ° C to 180 ° C; Preparing a mixture for a film by mixing more than 0% by weight and less than 10% by weight of the masterbatch and 90% by weight to less than 100% by weight of polyethylene; Preparing the film having a thickness of 60 to 80 μm by extrusion molding while maintaining the mixture for film at 100 ° C to 180 ° C; And manufacturing a container with the film; including, preparing a kimchi storage container having acetic acid removal function, characterized in that sodium carbonate is adjusted to contain 0.2 wt% to 2 wt% in preparing the mixture for the film. Method ”is disclosed,

Next, as a prior art related to the biodegradable polylactic acid multi-layer sheet with improved heat resistance, "Korean bio-patent publication No. 10-2012-0039866 (2012. 04. 26. published) biodegradable multi-layer sheet excellent in heat resistance" As disclosed in, "the content of the outer layer (B, upper and lower layers) composed of 10 to 40 parts by weight of polylactic acid (PLA) having a content of 3 mol% or less of D-isomer, and a content of D-isomer of 8 mol % Or less than the polylactic acid (PLA) 60 to 90 parts by weight of the inner layer (A, the middle layer) is a biodegradable polylactic acid excellent heat resistance, characterized in that made of a layer formed between the upper and lower outer layer (B) Multilayer sheet ”is disclosed.

However, the inorganic mineral antimicrobial composition in which the natural extract is introduced and the packaging material using the antimicrobial coating agent are prepared by using a water-soluble binder containing a urethane resin as an antimicrobial composition in which a composition for antibacterial is mixed with natural or synthetic minerals and natural extracts extracted from plants. As it is manufactured and coated on a substrate layer that is not biodegradable, when preparing food packaging containers, it has only antimicrobial properties and cannot have deodorization, antioxidant and heat resistance, and the kimchi storage container having the acetic acid removal function is deodorant carbonic acid As it is manufactured by mixing sodium hydrogen and polyethylene (POLYETHYENE), it is equipped with a deodorizing function in the manufacture of a food packaging container, but cannot have antibacterial, antioxidant, and heat resistance, and the biodegradable polylactic acid multilayer sheet having excellent heat resistance is D- As the sheet having the upper and lower layers and the intermediate layer is manufactured by varying the content of the isomer, it is difficult to manufacture the sheet and cannot have antibacterial, deodorizing, and antioxidant properties, and thus the food packaging container using the above prior art When manufactured, there is a problem that transparency is significantly reduced.

Korean Patent Publication No. 10-2017-0026274, "Inorganic mineral antibacterial composition with natural extracts and packaging materials using the same and method for manufacturing the same" (published on March 9, 2017) Korean Patent Registration No. 10-1705604 "Method for manufacturing kimchi storage containers with acetic acid removal function" (announced on Feb. 06, 2017) Korean Patent Application Publication No. 10-2012-0039866, "Biodegradable multi-layer sheet with excellent heat resistance" (published on April 26, 2012)

The present invention was created to solve the above-mentioned problems in view of the above-mentioned problems, and its purpose is to be composed of a material capable of biodegrading by microorganisms, to improve heat resistance and transparency, and to contain anti-fogging properties by including a hydrophilic agent in the outer layer. It is to provide a biodegradable sheet composition with improved heat resistance and transparency, and a method for manufacturing the same, so as to improve the temperature.

The present invention for achieving the above object is 79 to 89.6% by weight of polylactic acid, 1 to 5% by weight of polybutylene adipelephthalate, 9 to 15% by weight of talc, ethylene bis steamide, relative to 100% by weight of the entire inner layer. An inner layer composed of ~ 0.6% by weight, 0.1 to 0.3% by weight of the first antioxidant, and 0.1 to 0.3% by weight of the second antioxidant; It is characterized in that it is integrally laminated on the upper surface of the inner layer, the outer layer composed of 90 to 97% by weight of polylactic acid and 3 to 10% by weight of a hydrophilic agent relative to 100% by weight of the outer layer.

The composition of the inner layer is 84.2% by weight of polylactic acid, 3% by weight of polybutylene adiptelphthalate, 12% by weight of talc, 0.4% by weight of ethylene bis steamide, 0.2% by weight of primary antioxidant, 0.2% by weight of secondary antioxidant It is composed of.

The composition of the outer layer is composed of 95% by weight of polylactic acid and 5% by weight of hydrophilic agent.

The thickness ratio of the inner layer and the outer layer is 68 to 72: 28 to 32.

The hydrophilic agent of the outer layer is at least one selected from the group consisting of sorbitan mono laurate, sorbitan mono palmitate, sorbitan mono stearate, and mono glyceride.

Other characteristic elements of the present invention include 79 to 89.6% by weight of polylactic acid, 1 to 5% by weight of polybutylene adipatephthalate, 9 to 15% by weight of talc, 0.2 to 0.6% by weight of ethylene bis steamide, primary oxidation A first pellet manufacturing step of stirring the inner layer materials composed of 0.1 to 0.3% by weight of the antioxidant and 0.1 to 0.3% by weight of the secondary antioxidant in a first stirrer and preparing in pellet form; A second pellet manufacturing step of stirring the outer layer materials composed of 95% by weight of polylactic acid and 5% by weight of a hydrophilic agent in a second stirrer and producing pellets; A material input step of putting the inner and outer layer materials produced in the first and second pellet manufacturing steps into an extrusion molding machine to be separated through a feed block; A molding step of heating the inputted materials to be separated into the extrusion molding machine side through the feed block in a liquid material state and extruding to combine the liquid materials into a sheet; And a cooling step of cooling the sheet formed in the forming step using a cooling roller. A coating step of coating the release coating liquid using a coating roll on the surface of the sheet passing through the measuring step after the cooling step; A drying step of drying the surface of the coated sheet using a heating device; And a winding step of winding the sheet dried by passing through the drying step using a winding roll.

In addition, the present invention is manufactured such that the ratio of the thickness of the inner layer and the outer layer constituting the sheet in the forming step has a ratio of 68 to 72:28 to 32.

In the forming step, the inner layer is manufactured to be divided into first and second layers, and the sheet is made of a multi-layered sheet having three layers.

A measurement step of measuring the thickness of the sheet while feeding a plurality of laser detection sensors measuring the thickness of the sheet subjected to the cooling step within a range of the width of the sheet and feeding back the control unit to the extrusion molding machine when an abnormality occurs is further provided. .

When the plurality of laser detection sensors are moved in the measurement step, the plurality of laser detection sensors are configured to move at every lip interval of the extrusion molding machine.

In the present invention, polylactic acid is formed in the inner layer 110 and the outer layer 120, respectively, and the polybutylene adipelephthalate component is formed in the inner layer 110 to be biodegradable, and a talc component is contained in the inner layer. The heat resistance can be improved, and ethylene bis steamide (EBS) and primary and secondary antioxidants are added to form a uniform thickness and prevent discoloration, thereby improving the transparency of the sheet 100.

In addition, the present invention can improve the anti-fogging property of the surface of the sheet 100 by containing a hydrophilic agent in the outer layer 120.

On the other hand, the manufacturing method of the present invention, after preparing the component materials constituting the inner layer 110 and the outer layer 120 in a pellet form, the materials of the inner layer 110 and the outer layer 120 produced in a pellet form in an extrusion molding machine Since the inner layer 110 and the outer layer 120 are extruded in the form of a sheet 100 separated by input and heating, biodegradation is possible due to the PLA components of the inner layer 110 and the outer layer 120, and the inner layer 110 It is excellent in heat resistance and transparency due to the components, it is possible to manufacture the sheet 100 is improved anti-fogging due to the hydrophilic component of the outer layer 120.

In addition, according to the manufacturing method of the present invention, by accurately measuring the thickness of each portion of the sheet 100 to be transported by the laser sensor in a fixed state, the thickness can be accurately measured, if the user wants It has the advantage of continuously measuring by moving the laser detection sensor by the lip spacing that can control the thickness of the actual sheet 100.

1 is a cross-sectional view schematically showing a sheet structure composed of a sheet composition of the present invention.
2 is a test report for testing the transparency of the biodegradable sheet composition of the present invention,
3 is a test report for testing the heat resistance of the biodegradable sheet composition of the present invention.
4 is a flowchart sequentially showing a method of manufacturing a biodegradable sheet composition having improved heat resistance and transparency according to the present invention.
Figure 5 is a process diagram schematically showing the manufacturing process of the sheet composition of the present invention.

The present invention improves the heat resistance and transparency of the eco-friendly biodegradable sheet, so that it can contain a product at a hot temperature and can not only give a beautiful appearance, but also improve antifogging properties.

Hereinafter, a biodegradable sheet composition having improved heat resistance and transparency according to the present invention and a method of manufacturing the same will be described in more detail through detailed description of embodiments with reference to the drawings.

In describing the present invention, when it is determined that detailed descriptions of related known technologies or configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to a user's intention or custom. Therefore, the definition should be made based on the contents throughout this specification. In addition, "including" a component means that other components may be further included, not excluded, unless otherwise stated.

The biodegradable sheet composition with improved heat resistance and transparency according to the present invention, as shown in FIG. 1, 79 to 89.6% by weight of polylactic acid, polybutylene adipatephthalate 1 based on 100% by weight of the entire inner layer 110 An inner layer 110 consisting of ˜5% by weight, 9 to 15% by weight of talc, 0.2 to 0.6% by weight of ethylene bis steamide, 0.1 to 0.3% by weight of the first antioxidant, and 0.1 to 0.3% by weight of the second antioxidant; It is integrally laminated on the upper surface of the inner layer 110, and the outer layer 120 is composed of 90 to 97% by weight of polylactic acid and 3 to 10% by weight of a hydrophilic agent relative to 100% by weight of the total.

Polylactic acid (PLA: Polylactic Acid) of the inner layer 110 is a polymer produced from plants to be biodegradable, for example, PLA4032D product of the manufacturer Natureworks may be employed.

The polybutylene adipate-co-terepthalte (PBAT) is a resin for biodegradable films that has excellent tensile and tear strength, biodegradability and processability, and employs SOLPOL-1000 products from manufacturer Geosol Tech. Can be.

The talc (TALC, talc) is to provide heat resistance and rigidity, it can be adopted a CAS NO 14807-96-6 product of Cots.

The ethylene bis stearamide (EBS: Ethylene Bis Stearamide) is a dispersant that acts as a slip agent to uniformly produce the sheet 100 when extruding the sheet fabric, for example, employs EBS products from the manufacturer Shinwon Chemical.

The primary antioxidant serves to prevent the chain reaction of the radicals to stabilize the polymer, the melting point (melting temperature) is 110 ~ 130 ℃, to prevent oxidation and discoloration under the influence of the external environment , Adeka products of the manufacturer Adeka can be adopted.

The primary antioxidant may be phenol-based or arylamine-based, but phenol-based plastics may be employed here.

The secondary antioxidant performs the function of decomposing a peroxide to stabilize the polymer by removing oxygen atoms of the already oxidized polymer, the melting point (melting temperature) is 180 to 190 ° C, and oxidation and To prevent discoloration, it is possible to employ 2212 products from manufacturer Adeka.

The secondary antioxidant may be sulfur-based or phosphorus-based, but phosphorus-based antioxidants are used herein.

In the component ratio of the inner layer 110, polylactic acid (PLA) of the inner layer 110 occupies 79.0 to 89.6% by weight with respect to the total 100% by weight of the inner layer 110, when less than 79.0% by weight , Sheet 100 physical properties are strengthened, the sheet 100 is good, but there is a fear that unmolding occurs during molding. Conversely, when it exceeds 89.6% by weight, the properties of the sheet 100 are weakened, and the surface of the sheet 100 is weakened. There is a fear that the state becomes poor and the sheet fabric is torn during molding.

The polybutylene adiptelphthalate is 1.0 to 5.0% by weight relative to the total 100% by weight of the total inner layer 110, wherein when it is less than 1.0% by weight, the sheet reinforcing ability decreases, and conversely, when it exceeds 5.0% by weight There is a possibility that unmelted lumps are generated in the middle of the sheet fabric.

The talc is composed of 9.0 to 15.0% by weight relative to the total total weight of the inner layer 110, at this time, when the talc is less than 9.0% by weight, the heat resistance of the sheet 100 is lowered, on the contrary, when 15.0% by weight is exceeded When forming the sheet 100, there is a fear that an unformed portion is generated.

The ethylene bis steamide is composed of 0.2 to 0.6% by weight based on 100% by weight of the total inner layer 110, and if it is less than 0.2% by weight, the uniformity of the sheet 100 decreases and there is a risk of thickness variation, 0.6 There is a disadvantage in that the cost increases when the weight is exceeded.

The primary antioxidant is composed of 0.1 to 0.3% by weight with respect to the total total weight of the inner layer 110, 0.1 to 0.3% by weight, if less than 0.1% by weight, there is a risk of oxidation and discoloration under the influence of the external environment, when more than 0.3% by weight There is a disadvantage that the cost burden is increased.

The secondary antioxidant is composed of 0.1 to 0.3% by weight relative to the total total 100% by weight of the inner layer 110, when less than 0.1% by weight may be oxidized and discolored under the influence of the external environment, when more than 0.3% by weight There is a disadvantage that the cost burden is increased.

Therefore, the most preferred composition ratio of the inner layer 110 of the present invention is 84.2% by weight of polylactic acid, 3% by weight of polybutylene adipatephthalate, 12% by weight of talc, ethylene bis steamide 0.4 of 100% by weight of the total inner layer 110 It is composed of weight%, 0.2% by weight of the first antioxidant, and 0.2% by weight of the second antioxidant.

On the other hand, polylactic acid (PLA: Polylactic Acid) of the outer layer 120 is a polymer produced by plants to be biodegradable, for example, PLA2003D from Natureworks, a manufacturer used for thermoforming, coating, injection molding, broforming and textile manufacturing. Can be employed.

The hydrophilic agent is an antistatic agent and anti-fogging agent coated on the surface of the sheet 100, and is at least one selected from the group consisting of sorbitan mono laurate, sorbitan mono palmitate, sorbitan mono stearate, and mono glyceride, which are high molecular materials. The above can be selected, and as an example, the manufacturer TAKEMOTO's CYF-001 product can be adopted.

The polylactic acid of the outer layer 120 is composed of 90.0 to 97.0% by weight relative to the total 100% by weight of the outer layer 120, and when it is less than 90.0% by weight, the physical properties of the sheet 100 are enhanced, so that the sheet 100 is good but molded There is a fear that unforming may occur. On the contrary, when it exceeds 97.0% by weight, the physical properties of the sheet 100 are weakened and the surface condition of the sheet 100 becomes poor, and there is a fear that the sheet fabric is torn during molding. have.

The hydrophilic agent is composed of 3.0 to 10.0% by weight relative to the total 100% by weight of the outer layer 120, when less than 3.0% by weight, the anti-fogging property of the surface of the sheet 100 decreases, whereas 10.0% by weight If it exceeds%, there is a concern that the surface of the sheet 100 may be stained.

The most preferable composition ratio of the outer layer 120 is composed of 95.0% by weight of polylactic acid and 5.0% by weight of a hydrophilic agent based on 100% by weight of the outer layer 120.

The thickness ratio of the inner layer 110 and the outer layer 120 is 68 to 72: 28 to 32, and the most preferable thickness ratio is formed by the thickness ratio of the inner layer 110 and 70 and the outer layer 120 and 30.

When the thickness of the inner layer 110 is less than 68, the heat resistance of the sheet 100 decreases, and when the thickness of the inner layer 110 exceeds 72, the antifogging function is adversely affected.

In addition, when the thickness of the outer layer 120 is less than 28, the anti-fogging function decreases, and when the thickness of the outer layer 120 exceeds 32, there is a burden of cost increase.

It is preferable that the polylactic acid of the inner layer 110 adopts PLA4032D of Natureworks, which has excellent heat resistance, and the polylactic acid of the outer layer 120, respectively, adopts PLA2003D of Natureworks, which has excellent transparency.

Due to this, the biodegradable sheet composition having improved heat resistance and transparency according to the present invention has talc and ethylene bis steamide, primary antioxidant and secondary oxidation while allowing polylactic acid and polybutylene adiptelphthalate components to have biodegradability. The inhibitor component imparts heat resistance and transparency.

The test report for testing the biodegradable sheet composition prepared in the above-described manner is described in FIGS. 2 and 3, and FIG. 2 is a test report related to transparency of the sheet tested by the Korea Institute of Industrial Technology, transmittance meter (Nippon Denshoku; Model name NDH5000) is a test report comparing the transparency with a general PLA sheet. The test method was tested using the ASTM D 1003 method, and the results are shown in Table 1 below.

Sample name unit Test result Test Methods T.T HAZE P.T DIF Comparative example % 86.40 13.18 75.02 11.38 ASTM D 1003 Example 1 % 91.09 6.56 85.12 5.97 ASTM D 1003 Example 2 % 92.84 3.16 89.9 2.94 ASTM D 1003

That is, while the total light transmittance (TT) of the general PLA sheet, which is a comparative example, is 86.40, haze is 13.18, parallel line transmittance (PT) is 75.02, and the diffuse transmittance (DIF) is 11.38, Examples 1 and 2 The experimental values of TT, HAZE, PT, and DIF of are relatively improved than those of the comparative examples, resulting in increased transparency.

3 is a test report related to the heat resistance of the sheet tested by the Korea Institute of Industrial Technology, and tested the heat resistance of the sheet using a differential scanning calorimeter (Model DSC 250 manufactured by TA Instrument waters LLC), and the results are shown in the table below. Same as 2.

Sample name Glass Transition Temperature (unit ℃) Melting Temperature
(Unit ℃) Comparative example 55.17 146.10 Example 1 56.89 171.98 Example 2 57.80 172.96

Even in this case, as shown in Table 2, it is possible to obtain a result in which the heat resistance of Example 1 and 2 is increased as compared with Comparative Example.

It can be seen that the biodegradable sheet composition having improved heat resistance and transparency of the present invention has improved heat resistance and transparency in Example 1 and 2, compared to the general PLA sheet as a comparative example.

Therefore, the present invention is composed of polylactic acid in the inner layer 110 and the outer layer 120, respectively, and the inner layer 110 is composed of a polybutylene adipelephthalate component to enable biodegradation by microorganisms, and the inner layer. To contain the talc component can improve the heat resistance, ethylene bis steamide (EBS) and primary and secondary antioxidants are added to form a uniform thickness and prevent discoloration to improve the transparency of the sheet 100 Have an advantage.

In addition, the present invention can improve the anti-fogging property of the surface of the sheet 100 by containing a hydrophilic agent in the outer layer 120.

On the other hand, the method of manufacturing a biodegradable sheet having improved heat resistance and transparency according to the present invention, as shown in FIGS. 4 and 5, 79 to 89.6% by weight of polylactic acid, the composition described above, polybutylene adipelephthalate 1 Made of inner layer 110 materials consisting of ~ 5 wt%, talc 9-15 wt%, ethylene bis steamide, 0.2-0.6 wt%, primary antioxidant 0.1-0.3 wt%, and secondary antioxidant 0.1-0.3 wt% A first pellet manufacturing step (S1-1) of stirring in a stirrer and producing pellets; A second pellet manufacturing step (S1-2) of stirring the materials of the outer layer 120 composed of 95% by weight of polylactic acid and 5% by weight of a hydrophilic agent in a second stirrer and producing pellets; The first and second pellet manufacturing step (S1-1, S1-2) of the pellets produced in the inner and outer layers (110,120) material input into the extrusion molding machine 10 to be separated through the feed block 15 Step S2; A molding step (S3) of heating the inputted materials to be separated into the extrusion molding machine 10 side through the feed block 15 in a liquid material state and extruding to mix the liquid materials into a sheet 100; And a cooling step (S4) for cooling the sheet 100 formed in the forming step (S3) using a cooling roller (20). A coating step (S5) of coating the release coating liquid, which is a normal process, by using a coating roll 30 on the surface of the sheet 100 passed through the cooling step (S4) and then through the measurement step (S4-1); A drying step (S6) of drying the surface of the coated sheet 100 using a heating device 40; And a winding step (S7) of winding the sheet 100 dried while passing through the drying step (S6) using a winding roll (50).

In the first and second pellet manufacturing steps (S1-1, S1-2), the component materials of the inner layer 110 and the outer layer 120 are stirred in each stirrer and heat-extruded, and then cut and aged to pellets. It has a manufacturing process.

At this time, in the forming step (S3), the thickness ratio of the inner layer 110 and the outer layer 120 constituting the sheet 100 is manufactured to have a ratio of 68 to 72:28 to 32.

In the forming step (S3), the inner layer 110 is manufactured to be divided into first and second layers, and the sheet 100 is composed of a total of three layers of the inner layer 110 and the outer layer 120, which are the first and second layers. It can be made of a multi-layer sheet.

The thickness of the sheet 100 is measured while moving a plurality of laser detection sensors 25 measuring the thickness of the sheet 100 that has undergone the cooling step (S4) within a range of the width of the sheet 100, and the abnormality is measured. When it occurs, a control step (not shown) further comprises a measurement step (S4-1) of feeding back to the extrusion molding machine 10 side.

When the plurality of laser detection sensors 25 are moved in the measurement step (S4-1), the plurality of laser detection sensors 25 are configured to move at every lip interval of the extrusion molding machine 10 will be.

The laser detection sensor 25 measures the thickness of each portion of the sheet 100 to be transported using a laser scan method, outputs the measured information to the control unit side, and displays an occurrence of an abnormality when the control unit determines that the thickness is abnormal. Thus, after the operator recognizes this, the extrusion molding machine 10 is adjusted to provide feedback so that the thickness of the sheet 100 can be adjusted.

That is, in the measurement step (S4-1), a plurality of laser detection sensors 25 are separated by means of moving the width of the die 100 of the T die extrusion molding machine 10 with respect to the sheet 100 in the width direction. It is provided.

Therefore, the manufacturing method of the present invention, after preparing the component materials constituting the inner layer 110 and the outer layer 120 in a pellet form, extruding the material of the inner layer 110 and the outer layer 120 produced in a pellet form ( 10) Since the inner layer 110 and the outer layer 120 are extruded in the form of a sheet 100 separated by inputting and heating, biodegradation is possible due to the PLA components of the inner layer 110 and the outer layer 120, It is excellent in heat resistance and transparency due to the component 110, and it is possible to manufacture the sheet 100 having improved antifogging properties due to the hydrophilic component of the outer layer 120.

In addition, according to the manufacturing method of the present invention, by accurately measuring the thickness of each portion of the sheet 100 to be transported by the laser detection sensor 25 in a fixed state, accurate thickness measurement can be made, and the user If it is desired, it has the advantage of continuously measuring by moving the laser sensor 25 by the lip spacing that can control the thickness of the actual sheet 100.

As described above, although specific embodiments have been described in the detailed description of the present invention, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the above-described embodiment, but should be defined by the claims and equivalents as well as the claims below.

That is, the present invention as described above is not limited to the specific preferred embodiments described above, and who has ordinary knowledge in the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. Of course, various modifications are possible, and such changes are within the scope of the claims.

10: extrusion molding machine 15: feed block
20: cooling roller 25: laser detection sensor
30: coating roll 40: heating device
50: winding roll 100: sheet
110: inner layer 120: outer layer

Claims (10)

79 to 89.6% by weight of polylactic acid, 1 to 5% by weight of polybutylene adipatephthalate, 9 to 15% by weight of talc, 0.2 to 0.6% by weight of ethylene bis steamide, primary for 100% by weight of the entire inner layer 110 An inner layer 110 composed of 0.1 to 0.3% by weight of antioxidant and 0.1 to 0.3% by weight of secondary antioxidant;
The outer layer 120 is integrally laminated on the upper surface of the inner layer 110, and composed of 90 to 97% by weight of polylactic acid and 3 to 10% by weight of a hydrophilic agent relative to 100% by weight of the outer layer 120.
The thickness ratio of the inner layer 110 and the outer layer 120 is 68 to 72: 28 to 32,
The primary antioxidant has a melting temperature of 110 to 130 ° C, a phenolic antioxidant, and the secondary antioxidant has a melting temperature of 180 to 190 ° C, a phosphorus-based antioxidant with improved heat resistance and transparency. Sheet composition. The method according to claim 1,
The composition of the inner layer 110 is 84.2% by weight of polylactic acid, 3% by weight of polybutylene adiptelphthalate, 12% by weight of talc, 0.4% by weight of ethylene bis steamide, 0.2% by weight of primary antioxidant, and 2nd antioxidant A biodegradable sheet composition having improved heat resistance and transparency, characterized by being composed of 0.2% by weight. The method according to claim 1,
The composition of the outer layer 120 is a biodegradable sheet composition with improved heat resistance and transparency, characterized in that it comprises 95% by weight of polylactic acid and 5% by weight of a hydrophilic agent. delete The method according to claim 1,
Biodegradation with improved heat resistance and transparency, characterized in that the hydrophilic agent of the outer layer 120 is at least one selected from the group consisting of sorbitan mono laurate, sorbitan mono palmitate, sorbitan mono stearate, and mono glyceride. Sex sheet composition. 79 ~ 89.6% by weight of polylactic acid, 1 ~ 5% by weight of polybutylene adiptelphthalate, 9 ~ 15% by weight of talc, 0.2 ~ 0.6% by weight of ethylene bis steamide, 0.1 ~ 0.3% by weight of primary antioxidant, 2nd A first pellet manufacturing step (S1-1) of stirring the materials of the inner layer 110 composed of 0.1 to 0.3% by weight of the antioxidant in a first stirrer and producing pellets;
A second pellet manufacturing step (S1-2) of stirring the materials of the outer layer 120 composed of 95% by weight of polylactic acid and 5% by weight of a hydrophilic agent in a second stirrer and producing pellets;
The material injection step (S2) for introducing the materials of the inner and outer layers (110, 120) prepared in the first and second pellet manufacturing steps (S1-1, S1-2) into the extrusion molding machine 10 to be separated through the feed block 15 )Wow;
Through the feed block 15, the materials inputted to be divided into the extrusion molding machine 10 are heated to a liquid material state, and the liquid materials are extruded to be combined into the inner layer 110 and the outer layer 120 to be formed into a sheet 100. A forming step (S3);
A cooling step (S4) for cooling the sheet 100 formed in the forming step (S3) using a cooling roller 20;
The thickness of the sheet 100 is measured while moving a plurality of laser detection sensors 25 measuring the thickness of the sheet 100 that has undergone the cooling step (S4) within a range of the width of the sheet 100, and the abnormality is measured. It includes; a measurement step (S4-1) of feedback from the control unit to the extrusion molding machine 10 when it occurs;
In the forming step (S3), the thickness ratio of the inner layer 110 and the outer layer 120 constituting the sheet 100 is 68 to 72: 28 to 32,
The primary antioxidant has a melting temperature of 110 to 130 ° C, a phenolic antioxidant, and the secondary antioxidant has a melting temperature of 180 to 190 ° C, a phosphorus-based antioxidant,
In the measurement step (S4-1), the plurality of laser detection sensors 25 is configured to move at every lip interval of the extrusion molding machine 10 Heat and transparency improved biodegradable sheet manufacturing method. The method according to claim 6,
A coating step (S5) of coating the release coating liquid using a coating roll (30) on the surface of the sheet (100) passing through the cooling step (S4) after the measurement step (S4-1);
A drying step (S6) of drying the surface of the coated sheet 100 using a heating device 40; And
Of the biodegradable sheet having improved heat resistance and transparency, further comprising; a winding step (S7) of winding the sheet 100 dried while passing through the drying step (S6) using a winding roll (50). Manufacturing method. The method according to claim 7,
In the forming step (S3), the inner layer 110 is manufactured to be divided into first and second layers, and the sheet 100 is made of a multi-layered sheet composed of three layers. Sheet manufacturing method. delete delete

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