KR101559960B1 - Manufacturing method of the pla coated papercup - Google Patents

Abstract

The present invention relates to a method for manufacturing a coated paper cup using a PLA and, specifically, to a method for manufacturing a coated paper cup by using a PLA, which allows a process to be simplified, reduces a waste of materials, and allows the final paper cup to have enough intensity when manufacturing a paper cup by using safe and eco-friendly biodegradable resin as a coating material. The method includes: a base paper preparation step of preparing a paper cup base paper, on which a cut region including a coating region and an adhesion region is separated, heated at a certain temperature; a melting step of forming a liquefied composition by heating a powder composition including a PLA element; a coating step of forming a coating layer by injecting the liquefied composition into a metallic mold, placed around the coating region on the heated paper cup base paper, and applying pressure; a hardening step of cooling the paper cup base paper, on which the coating layer is formed, by applying heat as gradually lowering temperature; and a paper cup manufacturing step of manufacturing a paper cup by separating the cut region from the paper cup base paper on which the coating layer is hardened.

Description

Technical Field [0001] The present invention relates to a method for manufacturing a coated paper cup using PLA,

The present invention relates to a method for producing a coated paper cup using PLA, and particularly, a process for manufacturing a paper cup using a safe and environmentally friendly biodegradable resin as a coating material is simplified, waste of material is small, The present invention relates to a method for manufacturing a coated paper cup using PLA.

In general, many disposable articles such as paper cups, water towels, spoons, chopsticks, etc. can be processed immediately after use and there is no need to clean up separately, so they are widely used in everyday life because of convenience. However, since such disposable products are usually discarded only once, there is a problem that the resources are wastefully wasted and environmental hormones are generated. In particular, environmental hormones are absorbed once in the body, accumulate without being released, causing abnormalities in hormone secretion, resulting in serious health problems.

In the case of paper cups, polyethylene (PE) is mainly used as a coating material for protecting paper materials from contents contained in the disposable articles. In the case of such a paper cup, the problem of the environmental hormone still occurs due to the coated polyethylene, and there is a problem that it is not significantly decomposed compared to the paper.

In order to solve the above problems, recently, a method of using PLA extracted from natural resources without using petroleum resources as a coating material of paper has been proposed, and Korean Patent No. 10-1110423 (hereinafter referred to as "cited invention" ).

The PLA resin film is produced by pressing a paper base material heated at 90 to 94 ° C and a molten PLA resin film at a temperature of 115 to 120 ° C under a pressure of 55 to 65 kgf / cm 2, wherein the PLA resin film is a spherical granular PLA raw material Is melted and kept in a molten state. Thus, the PLA raw material is transferred and laminated over the entire paper base paper by the above-described method.

However, in the case of the paper cup, the bottom of the circular shape forming the bottom and the side of the radial shape forming the side are cut to form the cup shape, and they are formed by three-dimensionally joining them. As in the cited invention, The bottom portion and the side portion are cut from the paper base paper and the remaining portions are all discarded in an unused state, so that the PLA coated at the beginning is not used yet, which is a waste point.

In addition, in forming the paper cup by combining the bottom portion and the side portion, the portion to be joined in the cylindrical shape between the bottom portion and the side portion or the side portion is essentially accompanied by the adhesion. When the PLA is laminated on the adhesive portion, So that the strength of the paper cup as a whole is weakened.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to solve the above-mentioned problems by using environmentally friendly PLA as a coating material in a safe and naturally decomposed environment hormone during the production of paper cups, The present invention relates to a method for producing a coated paper cup using PLA.

According to another aspect of the present invention, there is provided a method of preparing a coated paper cup using PLA, comprising the steps of: preparing a paper cup raw material paper heated to a predetermined temperature by dividing a cutting region including a coating region and an adhesive region; A melting step of heating the powder composition comprising the PLA component to form a liquid composition; A coating step of injecting the liquid composition into a mold surrounding the coating area in the heated paper cup raw paper and pressurizing to form a coating layer; And a curing step of gradually cooling the raw paper of paper cup formed with the coating layer by applying heat at a low temperature; And separating the cut region from the cured paper cup raw paper to produce a paper cup.

According to the present invention, a coating layer composed mainly of PLA, which is a biodegradable resin, is formed on a paper cup, so that a safe and environmentally friendly paper cup can be obtained. In addition, manufacturing cost can be reduced by minimizing waste of PLA during manufacturing, The PLA coating is suppressed at the attachment site, so that the adhesive force is improved and the paper cup has sufficient strength.

1 is a flow chart showing a process of a method of manufacturing a coated paper cup using PLA according to the present invention.
2 is a schematic view of a region of a raw paper for making a paper cup according to the present invention.
3 is a schematic view showing the entire process of a method of manufacturing a coated paper cup using PLA according to the present invention.
4 is a schematic view showing a coating step in a method of manufacturing a coated paper cup using PLA according to the present invention.

In the present invention, a method for producing a coated paper cup is used in which a manufacturing process is simplified, a waste of a material is small, and a final paper cup has sufficient strength by using environmentally friendly PLA as a coating material, A raw paper preparing step of preparing a paper cup raw paper heated to a predetermined temperature by dividing a cutting region including a coating region and an adhesive region; A melting step of heating a powder composition comprising a PLA component and comprising the PLA as a main component to form a liquid composition; A coating step of injecting the liquid composition into a mold surrounding the coating area in the heated paper cup raw paper and pressurizing to form a coating layer; And a curing step of gradually cooling the raw paper of paper cup formed with the coating layer by applying heat at a low temperature; And separating the cut region from the cured paper cup raw paper to produce a paper cup.

The scope of the present invention is not limited to the embodiments described below, and various modifications may be made by those skilled in the art without departing from the technical scope of the present invention.

Hereinafter, a method of manufacturing a coated paper cup using the PLA of the present invention will be described in detail with reference to FIGS. 1 to 4.

As shown in FIG. 1, the method for preparing a coated paper cup using the PLA of the present invention includes a raw paper preparing step, a composition preparing step, a melting step, a coating step, a curing step, and a paper cup making step. Hereinafter, a process for preparing a paper cup, including a PLA component, from a preparing step of the composition including the PLA as a main component to a paper cup producing step, will be described in detail with reference to FIG. 1 and FIG.

(1) Stage preparation stage

2, the radial side portion 20 is adhered to the circular bottom portion 10 to form a three-dimensional shape. To this end, the circumference of the circular bottom portion and the bottom and side portions of the radial side portion are separately So that an adhesive is applied to these spaces and bonded to other parts to form a three-dimensional body.

Since the space in which the adhesive is applied is divided into the adhesive region A and the inside of the adhesive region A is a region containing contents such as drinks in the inside of the paper cup, do.

The entire region including the coating region C and the adhesion region A is formed as a cut region so as to be rolled into a roll of a predetermined width. Accordingly, the bottom 10 and the side 20 are cut according to the cutting area in the paper cup making step, and they are made into a paper cup by a known paper cup manufacturing method. At this time, the cutting region may be separated from the raw paper, but it may be a method in which the cutting portion is implicitly divided by the automatic equipment.

Meanwhile, in the method for producing a coated paper cup according to the present invention, PLA is limited to a coating area only in a raw paper, and the PLA coating requires a pretreatment for smooth coating on the paper.

That is, since PLA is melted and applied at a low temperature due to the nature of the material, when the temperature difference between the PLA and the adherend is high, sufficient adhesion may not be obtained and peeling may occur. In the present invention, Thereby reducing the temperature gap and enhancing the strong adhesion.

For this purpose, referring to FIG. 3, in the present invention, the paper raw paper P unrolled from the roll R is caused to pass through the chamber 100 having a high-temperature air atmosphere so that the temperature of the entire raw paper is firstly raised, And is wound around the roll 200 to concentrate on the surface of the paper to further increase the temperature. If heated through a high-temperature roll 200 immediately at room temperature without passing through a high-temperature air atmosphere, the paper may not be heated to a sufficiently high temperature or may be damaged due to instantaneous high temperatures.

At this time, it is preferable that the temperature of the air in the chamber 100 is maintained at 80-100 degrees and at least 15 seconds or more of the inside of the chamber 100 is elapsed.

On the other hand, it is advantageous that the temperature of the high-temperature roll 200 is gradually increased over a large number of times, for example, the temperature of the primary roll is about 80 degrees, the temperature of the secondary roll The temperature of the third roll and the temperature of the fourth roll are maintained at about 95 degrees, about 120 degrees and about 150 degrees, respectively, so that the surface temperature of the paper past the final fourth roll is maintained at about 100 degrees, Minimize it.

(2) Composition preparation step

In the present invention, PLA (polylactic acid) is the main material used for coating paper cups in the present invention, which is obtained by polymerizing starch through fermentation with glucose through plant resources such as corn.

Such PLA is harmless to the human body due to the absence of environmental hormones, and is eco-friendly since it is completely decomposed in the natural world when it is coated on paper cups and then discarded after use.

In order to use such PLA as a paper cup coating material, a composition comprising PLA as a main material formed of small particles so as to be easily melted is prepared, which facilitates fluidity and releasability during the heat molding of the powder composition, And an antioxidant added to prevent autoxidation by the action of oxygen which is likely to occur in the polymer substance.

Preferably, the powder composition comprises 83.45 wt.% Of PLA, 16 wt.% Of filler, 0.3 wt.% Of lubricant and 0.25 wt.% Of antioxidant and 0.1 wt.% Of primary antioxidant and 0.15 wt.% Of secondary antioxidant Lt; / RTI >

(3) Melting step

The powder composition containing the PLA component and containing the PLA component and containing the PLA as a main component is introduced into the melt pipe 500 through the hopper 400 as shown in FIG. The molten pipe 500 has a rotating screw therein to uniformly mix the charged powder composition and to form a liquid composition capable of forming by applying heat to the powder composition.

At this time, the temperature of the melt tube 500 is gradually lowered from 200 ° C to 125 ° C to heat the powder composition. This is because the melting crystal temperature of the biodegradable resin made of PLA is 200 ° C and the temperature is gradually lowered as the heat resistance temperature of the biodegradable resin increases at the time of heating. When the powder composition is heated to a temperature exceeding 200 캜 when it is melted, the powder composition is instantaneously burned. Therefore, the initial heating temperature is preferably about 200 캜.

In addition, at a suitable temperature for facilitating the formation of the liquid composition, the powder composition is heated to a temperature of 125 to 130 ° C to melt the liquid composition into a liquid composition, and at the same time, the temperature is lowered stepwise so that the liquid composition has an appropriate temperature.

For example, when the melt tube 200 comprises a plurality of spaces 210, 220 and 230, the temperature of the first melting space 210 is 200 ° C, the temperature of the second melting space 220 is 152 ° C, the temperature of the third melting space 230 Lt; RTI ID = 0.0 > 126 C. < / RTI >

As described above, according to the present invention, since the powder composition containing the biodegradable resin as a main component is melted in the liquid composition and then molded, the coating solution finally produced has an even distribution of PLA, .

(4) Coating step

The liquid composition formed through the melt tube 500 is introduced into the coater 600 as shown in FIG. In the coating machine 600, the paper raw material heated to a predetermined temperature is passed over the conveyor belt 610 firmly supported. During the process, the melted liquid composition is injected into the coating area C through the mold 620, The coating layer can be formed in the confined area.

The mold 620 is placed on the paper base with the bottom open and the paper outline having the same outline as the coating area in particular, and is pressurized with a strong pressure so that the injected liquid composition does not leak. When the PLA liquid composition melted through the melt tube 500 is injected into the mold 620 through the nozzle 630, the liquid composition is uniformly dispersed and gradually hardened to form a coating layer. When the coating is completed, the mold 620 The coating layer is formed only on the coating area C where the adhesive area A is excluded from the paper base paper.

4, the mold 620 may be moved in a rotary manner such that a plurality of the same molds 620 circulate while being in contact with the coating region C of the paper sheet, But may be embodied in various ways without limitation.

Meanwhile, a pressurizing unit (not shown) may be further provided inside the mold 620 to press the liquid composition, which has been spread widely after the injection, at the upper portion thereof so that the liquid composition can be applied more widely and uniformly. In this case, although the structure of the mold is complicated, there is an advantage of making the coating composition layer thinner.

The conveyor belt 610 is connected to a pipe 640 through which liquid flows and the conveyor belt 610 includes a boiler 650 for heating the liquid flowing through the pipe to supply hot water to the pipe . Therefore, the paper base paper P forming the coating layer by the metal mold 620 is maintained at a constant temperature of about 45 ° C to 55 ° C by hot water. When the liquid composition of about 125 to 130 ° C is cooled And the coating layer is easily separated from the mold 620 after the curing is performed.

(5) Curing step

The coating layer containing the PLA component and containing the PLA as a main component has a property of weakening in strength at the time of quenching and has a property of peeling from the adherend.

Therefore, the paper base paper P from which the coating layer is separated from the metal mold 620 passes through a plurality of heating rolls 700 having heating means as shown in FIG.

The heating roll 700 gradually lowers the temperature of the paper base paper P and moves the paper base paper while cooling the paper base paper P, and the temperature is gradually lowered from 90 ° C to 30 ° C. For example, when four heating rolls 700 are provided, the temperature of the first heating roll 710 is 90 ° C, the temperature of the second heating roll 720 is 80 ° C, the temperature of the third heating roll 730 is 60 ° C, The temperature of the last fourth heating roll 740 is preferably 30 占 폚.

By gradually cooling the coating layer as described above, the PLA coating layer of the finally produced paper cup can form a stable coating layer and has a high heat resistance temperature.

(6) Paper cup manufacturing step

When the PLA coating layer is cured on the paper base paper P, the bottom portion 10 and the side portion 20 are cut according to the cut region and a three-dimensional paper cup is formed through adhesion of the adhesive region A. According to the present invention, a coating layer is formed on the cut bottom part 10 and the side face part 20 in the adhesive area A, because the cutting of the base paper or the formation of the paper cup is performed according to a conventional technique, The coating layer is formed only in the coating region C, and the adhesive acts on the paper rather than the coating layer in the adhesive region A, thereby making it possible to firmly adhere to the paper.

As described above, the present invention forms a coating layer of a paper cup using PLA, and thus it is safe and environment-friendly. In addition, since a coating layer is formed only in a region where only the actual contents of the paper cup touch the paper base paper, PLA materials can be saved The PLA coated film is directly coated on the paper base material instead of the PLA-coated film, and the manufacturing process is simplified.

10: bottom part 20: side part
100: chamber 200: roll
400: hopper 500: melting pipe
600: Coater 610: Conveyor belt
620: mold 630: nozzle
640: pipe 650: boiler
700: heating roll
A: Adhesion zone C: Coating zone
R: Paper roll roll

Claims (7)

A paper preparation step of preparing a paper cup raw paper having a coating area and a cutting area including an adhesive area separated and heated to a predetermined temperature;
A melting step of heating the powder composition containing the PLA component to form a liquid composition;
A coating step of injecting the liquid composition into a mold surrounding the coating area in the heated paper cup raw paper to form a coating layer;
A curing step of gradually cooling the raw paper of the paper cup formed with the coating layer by applying heat at a low temperature; And
And a paper cup manufacturing step of manufacturing a paper cup by separating the cut region from the cured paper cup raw paper,
The powder composition is heated and moved along a melt tube containing a rotating screw therein,
Wherein the temperature of the melt tube is lowered stepwise from 200 ° C to 125 ° C and the powder composition is heated.
The method according to claim 1,
In the paper preparing step, heating of the paper-
A first heating step of passing the paper paper through a chamber having a high-temperature air atmosphere;
And a secondary heating step of winding the film on a roll having a high temperature, the temperature of which is gradually increased over a large number of rolls.
The method according to claim 1,
Wherein the powder composition comprises 83.45 wt% of PLA, 16 wt% of filler, 0.3 wt% of lubricant, and 0.25 wt% of antioxidant.
delete The method according to claim 1,
In the coating step,
And a PLA liquid composition is injected into the mold to form a PLA coating layer only on the coating region. The PLA coating layer is formed on the inner surface of the mold, A method for manufacturing a coated paper cup using PLA.
The method according to claim 1,
In the coating step,
The paper source passes the upper part of the solid conveyor belt, and a pipe through which the liquid flows is piped to the conveyor belt. The boiler further includes a boiler for heating the liquid. By supplying hot water to the pipe, Wherein the temperature of the coated paper cup is maintained.
The method according to claim 1,
Wherein the curing step comprises:
The paper sheet is cooled by passing through a plurality of heating rolls,
Wherein the temperature of the heating roll is gradually lowered from 90 ° C to 30 ° C.

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