KR101668321B1 - method for manufacturing disposble containers sheet and disposble containers manufactured by the method - Google Patents

Abstract

The present invention relates to a disposable container having an improved sealing surface, and more specifically, to a method for manufacturing a sheet for a disposable container and a disposable container manufactured thereby, in which a lid of the disposable container, i.e. the lid including polystyrene as the main component, can be peeled without damaging the sealing surface of the container body, such that no loose particles are generated upon opening the lid and none of a residual product in the container sticks to the inner surface of the lid. Also, when peeling off the lid which is hot-pressed to the disposable container, none of a residual product in the container sticks to the inner surface of the lid, and polystyrene powder is not generated. So, the sealing surface is improved and thus quality of the container is improved. The container of the present invention is hygiene and can solve inconvenience of users.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a sheet for a disposable container and a disposable container manufactured thereby,

Disclosed herein is a disposable container improved in sealing surface. More specifically, the present invention relates to a disposable container improved in sealing surface, in which the lid of the disposable container based on polystyrene, that is, the lid is peeled without damaging the sealing surface of the container body when the lid is opened, The present invention relates to a method of manufacturing a sheet for a disposable container and a disposable container manufactured by the method.

In general, cups, disposable beverage cups, disposable beverage cups, etc., which are used for disposable purposes, are joined to a body of a foamed body made of synthetic resin, particularly polystyrene, with a lid by a heat seal.

Such a disposable container must be removed for use. At this time, the residue of the synthetic resin foam, which is the container body, sticks to the inner surface of the lid, and the powder in the form of debris falls into the container, thereby causing dissatisfaction of the user.

In order to solve such a problem, Korean Patent Registration No. 10-1165342 discloses a method of providing an eyelash function to impart an adequate level of peel strength between a film coated on a surface of a container body and a film constituting a lid, And a container implemented therein.

However, such a container generally uses a biodegradable material rather than a mass-produced expanded polystyrene container, and since the container lid is manufactured with a complicated structure in which a second biodegradable film, a metal deposition layer, and a paper layer are laminated, There is a problem that it is not suitable for disposable beverage cups and the like.

Korean Patent Laid-Open Publication No. 10-2013-0127296 discloses a method for forming a bonding structure that facilitates peelability control by using a biaxially stretched polypropylene film as a lid material film in a container made of a thermoplastic resin material member. Korean Patent Publication No. 10-0760775 discloses a method for providing a heat-sealable peelable layer through a laminated multilayer polyester film.

However, such a biaxially stretched polypropylene film or multilayer polyester film is a material unsuitable for use as a lid for cups, instant rice, disposable beverage cups and the like. When used in a foam polystyrene container or the like, a container residue is not attached to the inner surface of the lid It is not easy to obtain a proper bonding strength, so that there is a great deal of difficulty in the process.

In other words, there is a need for a method of foaming polystyrene and a disposable container so that the sealing surface of the container body is not damaged when the lid of the disposable container based on polystyrene as a base material is mass-produced and the manufacturing cost is low.

Korea Patent No. 1165342 Korean Patent Publication No. 2013-0127296 Korean Patent No. 0760775

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a disposable container sheet manufacturing method in which residues of a container do not stick to the inner surface of a lid, And a main object thereof is to provide a disposable container manufactured.

In order to realize the above-described object, the present invention provides a method for producing a polyurethane foam, comprising the steps of: melting a mixture of poly-styrene as a main component by heating and pressurizing to dissolve the mixture; A first cooling step of supplying a foaming gas into a cooling roll to form a foaming member; a second cooling step of cooling the foamed foaming member to a cooling roller to cool the foamed foaming member; And a coating step of coating a resin on the upper surface of the foamed member through the cooling step to produce a sheet.

Further, in the foaming step of the present invention, the foaming member is further extruded into a hollow cylindrical shape, and then, after the foaming step, a step of cutting the upper end of the foaming member, 26 < 0 > C.

Further, the present invention provides a disposable container characterized in that the sheet manufactured as described above is put into a mold and compression-molded using upper and lower molding arms.

The upper and lower molding arms of the present invention are each compressed to a pressing depth of 140 to 145 mm and 150 to 155 mm. The disposable container is characterized in that the temperature during compression molding is 180 to 190 ° C.

In the method of manufacturing a sheet for a disposable container according to the present invention and the disposable container manufactured by the method as described above, when the lead thermally adhered to the disposable container is peeled off, the remainder of the container does not stick to the inner surface of the lead, and polystyrene powder is not produced The sealing surface can be improved and the quality of the container can be improved. Thus, it is possible to obtain an effect that the hygienic and user inconvenience can be solved.

1 is a perspective view showing a disposable container;
2 is a schematic flowchart of a method of manufacturing a sheet for a disposable container according to a preferred embodiment of the present invention.
3 is a schematic view showing a foaming step and a winding step in a conventional method for producing a sheet for a disposable container.
4 is a schematic view showing a foaming step and a winding step according to a preferred embodiment of the present invention.
FIG. 5A is a longitudinal sectional view of a foam member after a conventional foam step. FIG.
5B) is a longitudinal section of the foam member after the foaming step of the present invention.
6A) is a cross-sectional view of a sheet after a conventional coating step.
6B) is a cross-sectional view of the sheet after the coating step of the present invention.
7 is a schematic view showing a comparison of press depths of upper and lower side chambers when a conventional disposable container is manufactured.
8 is a schematic view showing a comparison of press depths of upper and lower side chambers when the disposable container of the present invention is manufactured.
FIG. 9 is a photograph showing the attachment of the container residue and the degree of peeling of the sealing surface during the conventional lead opening.
10 is a photograph showing the results of an adhesive tape peeling test on the sealing surface of the present invention.
11 is a photograph showing the results of lead peeling test on the sealing surface of the present invention.

Hereinafter, the present invention will be described in detail.

A typical method for manufacturing a disposable container using expanded polystyrene (hereinafter also referred to as a container) is to prepare a foamed polystyrene sheet through a process of melting and cooling polystyrene pellets, then heating the sheet, To form a shape.

Specifically, the process for producing the expanded polystyrene sheet is carried out by mixing polystyrene pellets, raw materials such as beads, a foaming agent, etc. and heating and pressing under the conditions of 170 to 240 캜 and 200 to 250 kg / cm 2 to dissolve them, Followed by a foaming process in which foaming gas (carbon dioxide, butane, etc.) is injected to form a foam, followed by secondary cooling and coating to prepare a sheet, which is wound and aged.

At this time, the coating corresponds to the outer surface of the container body when the sheet is formed into the container body, so that the outer surface of the container is smoothly formed, thereby minimizing the damage on the outer side of the container body and obtaining a beautiful appearance And the foam is formed of two high and low foamed layers having different degrees of foaming.

General Purpose Polystyrene (GPPS) and High Impact Polystyrene (HIPS) are mixed and used as raw materials for polystyrene pellet beads and the like in the production of the expanded polystyrene sheet by the above- A low foaming layer composed mainly of high-impact polystyrene is formed on the surface and a high-release layer mainly composed of general-purpose polystyrene is formed under the foaming layer after the foaming and the first and second cooling processes.

In addition, the general-purpose polystyrene is excellent in transparency and has excellent electrical properties, water resistance, coloring property, and processability, and thus is widely used in foam products such as disposable containers and the like. The general-purpose polystyrene is divided into two types according to the grade: intrinsic co-extrusion, extrusion, and high stiffness. In order to produce a foamed polystyrene sheet, it is preferable to use a PST (Polystyrene Paper) for extrusion.

In addition, the high-impact polystyrene has excellent impact resistance and mechanical properties and is excellent in workability formation, and is used in combination with general-purpose polystyrene to produce a foamed polystyrene sheet. In this case, the general-purpose polystyrene foam is foamed to form an expanded polystyrene (EPS) layer, but the high-impact polystyrene is not foamed relatively but exposed to the surface to form a coating layer.

As shown in FIG. 5A, it can be seen that the foam layer is composed of two foam layers having different degrees of foaming. This is because, in the foaming and cooling processes of general-purpose polystyrene having various particle sizes, And the degree of foaming of the layer is changed.

That is, the surface layer of the sheet usually has a small degree of foaming, so that a sheet produced according to a conventional manufacturing process of a foamed polystyrene sheet has a low foam layer on the surface and a high release layer having a relatively high foaming degree As shown in FIG.

In connection with the above, in the process of manufacturing a container from a foamed polystyrene sheet, synthetic resin is coated on a low-foaming layer as a surface of the expanded polystyrene sheet, and after aging for a certain period of time, it is heated to 170 to 200 ° C, Thereby producing a container of a desired shape.

At this time, a coating layer and a low foaming layer are formed on the outer side of the manufactured container, a high release layer is formed on the inner side, and the outer periphery of the container, that is, the sealing surface 1 is rounded, The sealing surface which is a portion in contact with the sealing surface is a high release layer and the lead is provided on the outer periphery of the container, that is, the surface of the high release layer which is the sealing surface, and sealed by thermocompression bonding to complete the packaging container.

Therefore, the sealing surface, which is the portion where the container and the lead are sealed, becomes the surface of the polystyrene foam layer having a relatively large degree of foaming and the back surface of the lead.

The lead may be made of a mixture of aluminum and paper in the case of cups, a foam layer of polystyrene in the case of Nato containers, and a mixed material of paper and plastic in other disposable containers. It is also used.

However, in any of the leads, the degree of foaming of the polystyrene foam layer abutting the lead is high, so that the density of the polystyrene particles is low. When the leads are removed, the residue of the foam layer adheres to the lid, It is inevitable that the problem of polystyrene powder occurring on the reverse side occurs.

As a result of searching for various process conditions to solve the problems of the prior art, the inventors of the present invention found that when the polystyrene foam layer contacting the backside of the lead has a relatively low foaming degree and has dense particles, I have found out that it does not.

Therefore, the container of the present invention is composed of a low-foaming layer, which is a first polystyrene foam layer having a relatively low degree of foaming, a high-release layer, which is a second polystyrene foam layer having a relatively high foaming degree, and a foamed polystyrene sheet, Characterized in that a low-foaming layer having a relatively low foaming degree and a backside portion of the lead are sealed by thermal bonding.

Such a sealing structure provides a disposable container improved in sealing surface 1 in which no residue of the container or powder is generated at the time of peeling off the lid as shown in the following embodiments.

In order to manufacture the disposable container improved in the sealing surface 1 of the present invention, first, a low foamed layer, which is a first polystyrene foamed layer having a relatively low degree of foaming, a high-foaming layer, which is a second polystyrene foamed layer having a relatively high foaming degree, It is necessary to produce a sequentially stacked foamed polystyrene sheet. However, the foaming layer having a relatively large foaming degree on the outer surface of the foam layer is inevitably formed by a usual manufacturing process.

Specifically, as shown in FIG. 3, a conventional expanded polystyrene sheet 20 '(hereinafter also referred to as' sheet 20 '') is prepared by dissolving a mixed raw material, The foaming member 10 'is foamed into a cylindrical shape through an extrusion die 100' by injecting a foaming gas, and the foamed member 10 'is molded by a cooling roller 200' for a secondary cooling process. The base (extrusion-molded base) is cut by using a dissecting apparatus to form a high release layer 14 'on the lower part of the low-foam layer 12', as shown in FIG. 5a, Passes through the roller 200 '.

The foam member 10 'having passed through the cooling roller 200' has a low foamed layer 12 'in the coater 300' while maintaining the positions of the low foamed layer 12 'and the high release layer 14' The sheet 20 'is formed by coating a synthetic resin on the top of the sheet 20', wound around the take-up roll 400, and aged for a few days to complete the production of the sheet 20 '.

That is, as shown in FIG. 6, a normal expanded polystyrene sheet 20 'is sequentially laminated from the bottom to a high release layer 14', a low foamed layer 12 'and a coating layer 16' , The sealing layer 1 is formed so that the coating layer 16 'is located outside the container body, so that a sealing surface 1 is formed on the high release layer 14' to seal with the leads, thereby attaching the leads.

Accordingly, in the present invention, when the secondary cooling is performed after the primary cooling and foaming steps, the foaming degree of the low foaming layer 12 and the fresh foaming layer 14 is relatively reduced by cooling to a lower temperature than the ordinary manufacturing process through quenching 5, the upper end of a cylindrical foam member 10 having a hollow formed thereon through which the extrusion die 100 is passed is cut and spread to pass through the cooling roller 200 for the secondary cooling The sheet 20 is formed by allowing the coating layer 16 to be formed on the high release layer 14 in the coater 300 after the hot release layer 14 is positioned on the low foam layer 12, Up roll 400 and aged for 10 days to complete the production of the sheet 20. [

That is, when the container body is molded using the completed sheet 20, since the low foamed layer 12 having a relatively low foaming degree becomes the inner surface of the container body, the foaming degree of the sealing surface And the surface roughness is alleviated, so that polystyrene powder or residue is not generated when the lead is peeled off.

The method for producing a sheet for a disposable container of the present invention and a conventional manufacturing method are compared as follows.

The method for producing the expanded polystyrene sheet (20) of the present invention and the conventional method for producing the expanded polystyrene sheet are carried out by mixing the starting materials such as polystyrene pellets, beads, foaming agents and the like and heating them under the conditions of 170 to 240 캜 and 200 to 250 kg / And then subjected to a foaming process for forming a low foaming material by injecting a foaming gas, followed by secondary cooling to prepare a sheet, winding it, and aging it .

However, the production method of the present invention is characterized in that the cooling condition is improved in the secondary cooling so as to control the degree of foaming of the foam layer.

In the ordinary manufacturing process, the secondary cooling performs cooling by performing both of the cooling of the cooling water through the cooling water into the inside of the roller and the cooling of the air by spraying air outside the roller, wherein the cooling of the inside of the roller is performed at about 27 to 30 DEG C , And the air cooling outside the roller is performed at about 25 to 26 占 폚.

In contrast, in the manufacturing method of the present invention, the secondary cooling is performed by cooling the inside of the rollers at 22 to 23 ° C, and the cooling of the outside of the rollers is performed at about 20 to 21 ° C.

That is, the secondary cooling condition of the present invention is obtained as a result of a lot of experiments. When the cooling temperature is below 22 ° C and the cooling temperature is lower than 20 ° C, the relative degree of foaming becomes too low, If the temperature of the cooling of the cooling water is 23 占 폚 and the temperature of the cooling of the air cooling is more than 21 占 폚, the degree of foaming of the foamed layer in the sealing part in contact with the lead is not sufficiently low and a part of polystyrene powder is generated during the peeling of the lead. It is very important to keep.

In addition, the expanded polystyrene foam layer produced by the method of the present invention exhibits a density of 15 to 30 kg / m 3 as a whole, but a 50% slice-divided sample is prepared for 50 of the foam layer, The average density difference between the low foamed layer 12 which is the first polystyrene foam layer and the high porosity layer 14 which is the second polystyrene foam layer is about 10 to 15 kg / m < 3 >, indicating that the foaming degree of the first polystyrene foam layer Was found to exhibit a relatively low degree of foaming than that of the second polystyrene foam layer.

Therefore, the relatively high and low layers of foaming can be classified as having a difference in average density between the foam layers compared to 10 to 15 kg / m < 3 >.

Next, when preparing the disposable container using the expanded polystyrene sheet 20 of the present invention and the ordinary manufacturing method, the expanded polystyrene sheet 20 is fed, the sheet 20 is heated and pressed with a die Which is similar in that it forms the shape of the container.

However, in the conventional production method, it is prepared by heating to 210 to 220 캜 and pressurizing with a mold, but in the present invention, heating to 180 to 190 캜 and pressurization with a mold are performed.

That is, if the heating temperature is lower than 180 deg. C, the forming process is not properly performed. If the heating temperature exceeds 190 deg. C, the foaming degree of the sealing surface 1 formed in the low foaming layer 12 is increased, A large foam layer is formed. As a result, there is a problem that residues are generated when the leads are peeled off.

In particular, in the case of heating at 210 to 220 캜 as in the conventional production method, the degree of foaming of the sealing surface 1 is greatly increased, and the degree of foaming of the foam layer contacting the bonding surface with the lead becomes relatively large. The problem that residues and polystyrene powder are generated at the time of peeling is not solved.

In addition, since the foamed polystyrene sheet 20 is cooled by lowering the temperature of the foamed polystyrene sheet 20 in the secondary cooling condition, the foamed foamed layer 12, which is not sufficiently foamed, is heated to 210 to 220 ° C And thus the conventional problems are not solved by foaming when molded.

Further, in order to improve the condition of the sealing surface 1, it is necessary to adjust the molding pressure at the time of pressing in order to alleviate the surface roughness.

That is, by increasing the molding pressure by 10 to 12% as compared with the conventional manufacturing method, the surface roughness of the sealing surface can be relaxed, and as a result, residues and polystyrene powder may be generated when the leads are peeled off.

For example, as shown in FIG. 7, when the manufactured sheet 20 'is put into the mold 500', the molding pressure of the upper mold arm 500 'of the mold 500' The pressing pressure of the lower molding arm 520 'is 158 mm, and the pressing depth of the lower molding arm 520' is 169 mm, the molding pressure in the manufacturing method of the present invention is as shown in FIG. 8, Is applied to the mold 500 and the pressure is increased by making the pressing depth of the upper molding arm 510 to be 142 mm and the pressing depth of the lower molding arm 520 to be 152 mm.

That is, the effect of increasing the pressure increases the pressure to be molded by bringing the position of the molding arm closer to the seat 20 when the length of the molding arm, that is, the distance to which the molding arm is moved for molding, is constant , Thereby obtaining the effect of alleviating the surface roughness of the sealing surface.

In other words, in the present invention, the foamed polystyrene sheet 20 is placed on the concave mold 500, and the upper and lower molding arms 510 and 520 press the upper and lower molds 510 and 520 to form the shape of the container. The pressing depth of the sealing surface is 150 to 160 mm and the pressing depth of the lower side is 160 to 170 mm. In the present invention, the pressing depth is set to 140 to 145 mm above the upper side and 150 to 155 mm to the lower side, .

The manufacturing method of the disposable container sheet 20 of the present invention will be described as follows.

First, the melting step (S10) of the present invention is a method of melting polystyrene-based mixture by heating, pressing and mixing, and mixing raw materials such as polystyrene pellets, beads, foaming agents and the like and heating at a temperature of 170 to 240 ° C and 200 to 250 kg / Heated and pressurized to dissolve.

Next, in the first cooling step (S20) of the present invention, the mixture dissolved in the melting step (S10) is cooled by a water-cooling regulating method and is gradually cooled at a temperature of 100 to 120 ° C.

Next, the foaming step S30 of the present invention is to form the foam member 10 by injecting the foaming gas into the mixture cooled in the first cooling step S20, and extruding and foaming the foaming member 10, The extrusion die 100 is extruded into a cylindrical shape having a hollow.

Next, the unfolding step S45 is a step of cutting the upper end of the foam member 10 after the foaming step S30. In order to perform the subsequent secondary cooling step and the coating step, And is supplied to the roller 200.

At this time, the foaming member 10 has a high release layer 14 disposed thereon and the low foam layer 12 is positioned below the high release layer 14 so that a synthetic resin Thereby realizing the effects of the present invention described above.

The second cooling step S40 is a step of cooling the foamed member 10 foamed in the foaming step S30 to the cooling roller 200 to cool the foaming member 10 in the spreading step S35 The foamed member 10 unfolded in the cooling roller 200 is supplied to the cooling roller 200 and the supplied foamed member 10 is cooled to a range of 21 to 26 占 폚, Cooling is preferably performed at about 20 to 21 DEG C, and the air cooling is performed at about 22 to 23 DEG C, and is most preferably performed within the same range as described above.

At this time, when the average cooling temperature of the cooling of the water-cooled state and the cooling of the air-cooled state was 21 ° C, the degree of foaming that maximized the effect of the present invention was exhibited.

Next, in the fixing step S50, the upper surface of the foam member 10 through the second cooling step S40 is coated with a resin to produce the sheet 20. As shown in FIG. 4, The foam member 10 having passed the roller 200 passes through the coater 300 and the upper surface thereof is coated.

At this time, the material used for the coating may be a polyethene coating, a latex coating, or the like, which is a commonly used synthetic resin material. Most preferably, the polystyrene foam and the polystyrene resin having little heterogeneity are coated, So that it is possible not only to induce smooth molding but also to reduce manufacturing cost.

Next, the collecting step S60 is a step of winding the resin-coated sheet 20 on the winding roll 400 in the coating step S50 so that it can be smoothly supplied to the mold 500 Not only is it possible to achieve easy storage effect.

Next, the aging step S70 completes the production of the sheet 20 by maintaining the natural ventilation of the sheet 20 wound in the collecting step S60, but aging for 10 days in the absence of direct sunlight.

Hereinafter, the disposable container manufactured using the sheet 20 will be described in detail. The sheet 20 is heated to 180 to 190 캜, most preferably 185 캜, After the injection molding, the upper and lower molding arms 510 and 520 of the mold 500 are compression molded to manufacture a container body.

At this time, the upper and lower molding arms 510 and 520 of the mold 500 are pressed at a pressing depth of 140 to 145 mm, 150 to 155 mm, and most preferably, 142 and 152 mm, respectively, As a result, the effect of alleviating the surface roughness of the sealing surface is realized.

That is, in the disposable container of the present invention, the polystyrene coating layer 16 is formed on the outer side surface, the high release layer 14 is formed on the upper side of the coating layer 16 in the inner side direction, The low foaming layer 12 having a relatively low degree of foaming is formed in comparison with the foaming degree of the foaming layer 14 so that the leads are thermally bonded to the sealing surface 1 formed on the low foaming layer 12, The effect of not generating residue and polystyrene powder can be obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It is possible to carry out various changes in the present invention.

1: sealing surface 10: foaming member
12: low foam layer 14: high release layer
16: Coating layer 20: Sheet (polystyrene foam sheet)
100: extrusion die 200: cooling roller
300: coater 400: winding roll
500: mold 510: upper molding arm
520: Lower molding arm

Claims (6)

(S10) for heating and pressurizing and dissolving a mixture of polystyrene as a main component at 170 to 240 DEG C under a condition of 200 to 250 kg / cm < 2 >
A first cooling step (S20) of cooling the mixture dissolved in the melting step (S10) at a temperature of 100 to 120 DEG C by a water-cooling regulating method; and
A foaming step S30 of injecting a foaming gas into the mixture cooled in the first cooling step S20 and extruding and foaming the foaming member 10 to form a hollow cylindrical foamed member 10;
A spreading step S35 of cutting the upper end of the cylindrical foam member 10 foamed in the foaming step S30;
The foaming member 10 foamed in the foaming step S30 is supplied to the cooling roller 200. The cooling of the inside of the roller is 22 to 23 占 폚 and the cooling of the outside of the roller is performed in the range of 20 to 21 占 폚 A second cooling step (S40); and
A coating step S50 of coating a resin on the upper surface of the foam member 10 through the second cooling step S40 to produce a sheet 20;
A collecting step (S60) of winding the resin-coated sheet (20) on the winding roll (400) in the coating step (S50); And
(S70) for aging the sheet (20) wound in the collecting step (S60) for 10 days in a state where natural ventilation is maintained but no direct sunlight is present .
delete delete The sheet 20 is heated to 180 to 190 캜 and then introduced into a mold 500. The upper and lower molding arms 510 and 520 of the mold 500 are pressed to have a pressing depth of 140 - 145 mm, 150 to 155 mm.
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