JP4129198B2 - Thermoplastic resin sheet for container molding and container - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to containers such as instant noodles from thermoplastic resin non-foamed sheets, thermoplastic resin foam sheets, or laminated sheets of thermoplastic resin foam sheets and non-foamed resin films (collectively referred to as container molding sheets). In particular, in a container in which a printed portion such as a design pattern or character display is partially formed, a printed portion such as a design pattern or character display (hereinafter referred to as these The present invention relates to a container-forming thermoplastic resin sheet suitable for obtaining a container having an improved bowl shape such as a shift, distortion, or variation thereof.
[0002]
[Prior art]
The thermoplastic resin foam sheet and a thermoplastic resin foam sheet in the symbol pattern or design pattern from the laminated sheet obtained by laminating a thermoplastic resin film having a partial print portion of the character display unit or the like and the character display unit or the like of the polystyrene foam sheet and the like conventionally The container in which the partially printed portion is formed is thermoformed by a vacuum forming method, a pressure forming method, a plug assist forming method, a match mold forming method, a forming method using a combination thereof, or the like. In this case, when the container is deep and the rising angle of the side wall is large, the thermoplastic resin sheet for molding provided at the time of molding partially increases in elongation rate. The degree of deformation of the partly printed portion is increased, and the partial printed portion is displaced or distorted. Therefore, it is necessary to deal with deviations and variations in the pattern and character display portion due to the difference in sheet elongation rate depending on the forming position and the characteristics of the sheet.
[0003]
As a means of this, in a method of molding a plurality of molded products with point designs from a thermoplastic resin foam sheet having a point design (partial printing part), the point of expansion is considered in consideration of the expansion rate of the foam sheet at the time of molding depending on the molding position. There is a method in which a design is formed at a position where the elongation percentage of the sheet is low at the time of molding a molded product, and a plurality of molded products with point designs are molded with both ends of the foam sheet clamped (for example, patents) Reference 1). In this method, the point design is on the portion of the sheet where the pattern or character printed portion has the lowest elongation rate when the container is molded, that is, the container forming portion on the imaginary line in the direction of about 45 degrees with respect to the longitudinal direction of the sheet. Was formed.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 60-56528.
[0005]
[Problems to be solved by the invention]
As described above, a container upper surface opening diameter (L) and a container side wall height (container depth) from a container-forming thermoplastic resin sheet having a partial printing part (hereinafter, sometimes simply referred to as a container-forming sheet). ) When forming a container in which a partial printing portion is formed by molding with a relatively small ratio (L / D) (hereinafter referred to as a drawing ratio), the pattern or character printing portion is molded into a container. Sometimes forming the portion of the sheet where the elongation percentage is the lowest, that is, the container forming portion on the imaginary line in the direction of about 45 degrees with respect to the longitudinal direction of the sheet, the displacement or distortion of the design pattern or the character printing portion or its variation. This is a method that has been widely adopted as a means for suppressing.
[0006]
However, a pattern or a character printing part is provided in a container forming part on a virtual line at a position where the elongation percentage of the sheet is low at the time of conventional molding, that is, approximately 45 degrees with respect to the longitudinal direction of the sheet at the time of container forming. When forming the container using the container forming sheet, it is completely possible that the printed part such as the design pattern and the character printing part may be displaced or distorted even if it is formed with great care. It is difficult to avoid, especially when the partial printing part displays characters such as quality display, date of manufacture, description, etc., there is a problem that the deviation or distortion variation is noticeable, and this is suppressed. It was requested.
In the present invention, when a container having a pattern and a character printing part is formed in thermoforming with a relatively small drawing ratio, the shift and distortion of the pattern and the character printing part, the wrinkle shape with improved variation, etc. It is an object of the present invention to provide a container-forming sheet suitable for obtaining such a container, and a container having a relatively small squeezed shape having a relatively small drawing ratio with improved variation in deviation and distortion of the pattern and character printing portion and variation thereof.
[0007]
[Means for Solving the Problems]
In thermoforming with a relatively small drawing ratio, the present inventors have found that when molding a container on which a pattern or character printing part is formed, the pattern pattern or character printing part is displaced or distorted, and the factors that cause variation are generated. The design pattern and the character printing part on the container forming part on the imaginary line in the direction of about 45 degrees with respect to the longitudinal direction of the sheet at the time of forming the container, that is, the position where the sheet has a low elongation rate when forming conventionally We reviewed the fact that the pattern is provided, and conducted various studies on the positions where the design pattern and the character printing part are formed.
As a result, when forming a plurality of containers at the same time, in a long container forming sheet in which a plurality of circular container forming portions are arranged in a lattice pattern substantially adjacent to each other, a position where the sheet has a low elongation rate at the time of forming Is drawn into a position where the elongation rate of the sheet becomes large at the time of container molding, and the size to be drawn also varies depending on the position of the circular container molding portion in the container molding sheet, and this takes into account the elongation rate at the time of molding. It has been found that even when the partial printing portion is formed at a place where the elongation percentage is small, the partial printing portion is displaced or distorted as a result.
[0008]
Therefore, as a result of re-examination of the position of the partial printing part formed in the circular container molding part in the container molding sheet, it was considered to be unsuitable in the past, the part having a high elongation rate at the time of molding, It is found that there is a part that extends uniformly compared with the part where the elongation rate is small, and by forming the partial print part in advance in consideration of the elongation rate at the part where the elongation rate is uniformly large, the deviation or distortion is unexpectedly generated. The occurrence was observed to be suppressed. The present invention has been made based on this fact.
[0009]
That is, the present invention
(1) In a long thermoplastic resin sheet in which a plurality of circular container molded portions are adjacently arranged in a grid shape in the width direction and / or the longitudinal direction , each circular container molded portion has a center of each circular container molded portion. A thermoplastic resin sheet for forming a container , wherein a design pattern and a character display part are partially formed on a virtual line in a width direction and / or a longitudinal direction connecting the two .
(2) The above-mentioned (1), wherein the container-forming thermoplastic composition resin sheet is obtained by laminating a thermoplastic resin film partially having a design pattern or a character display portion on a polystyrene resin foam sheet. The thermoplastic resin sheet for container molding as described.
(3) The container-forming thermoplastic resin sheet described in (1) or (2) above is thermoformed, and the container upper surface opening diameter (L) and the height of the container side wall (container depth) (D ) Ratio (L / D) is 0.8 to 3, a container in which a pattern or a character display part is partially formed.
Is a summary.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An example of an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a partially cutaway plan view of a container molding sheet according to the present invention in which a thermoplastic resin film is laminated on a thermoplastic resin foam sheet. Reference numeral 1 denotes a thermoplastic resin foam sheet, and 2 denotes a thermoplastic resin film. S shows the sheet | seat for container shaping | molding by which the printing thermoplastic resin film in which the partial printing part was formed in the thermoplastic resin foam sheet 1 was laminated | stacked. Reference numeral 3 denotes a circular container molding part (hereinafter simply referred to as a container molding part) in the thermoplastic resin film, and 4 denotes a partial printing part provided on the thermoplastic resin film in the container molding sheet of the present invention.
[0011]
In this invention, the partial printing part 4 is provided in the part in which the elongation rate shows the uniform elongation rate in the position where the elongation rate at the time of shaping | molding is the largest in the sheet | seat S for container shaping | molding. In the container forming sheet S in which a plurality of container forming portions 3 shown in FIG. 1 are adjacently arranged in a grid shape in the width direction and / or the longitudinal direction, the elongation rate is uniform at a position where the elongation rate at the time of molding is the largest. The portion showing a large elongation is the portion indicated by a and b shown in FIG. That is, in the container forming sheet S in which a plurality of container forming portions 3 are adjacently arranged in a grid shape in the width direction and / or the longitudinal direction, the width connecting the centers of the circular container forming portions of the circular container forming portions The portions located on the imaginary line in the direction and / or the longitudinal direction are a and b, and in the present invention, the partial printing portion 4 is at least one of the locations (in one container molding portion, near the periphery in the width direction and the longitudinal direction). at least one of a total of four portions corresponding to the portions a and b). In general, the partial printing unit 4 is provided in all four portions in the vicinity of the periphery in the width direction and the longitudinal direction.
[0012]
A container molding sheet S in which a printing thermoplastic resin film having a partial printing section 4 provided at such a position and a thermoplastic resin foam sheet are laminated is clamped at least at both ends in the width direction of the sheet to heat the container. By molding, it is possible to obtain a container in which the partial printing portion 4 is hardly displaced, distorted, or uneven. Further, during the thermoforming, if necessary, the peripheral edge of each container molding part 3 is clamped, and the sheet to the container molding part of the part other than the container molding part (container non-molding part) at the time of thermoforming By suppressing the pull-in, it is possible to more significantly reduce the occurrence of deviation, distortion, and variation of the partial printing unit 4. However, if the peripheral edge of the container molded part 3 is strongly clamped, the effect of drawing the sheet into the container molded part of the container non-molded part at the time of thermoforming cannot be expected, and the lip strength of the resulting container may be reduced. Therefore, the strength of the clamp should not be too strong. In addition, the heat of the sheet is formed in a substantially central part 5 (see FIG. 1) of the container non-molded part surrounded by four adjacent container molded parts 3 (arranged in a substantially square shape) on the container molding sheet. By providing a convex or concave molded part for suppressing the drawing of the non-molded part of the container into the molded part at the time of molding, it is possible to further reduce the occurrence of deviation or distortion of the partially printed part and its variation. In addition, by clamping the substantially central portion 5 of the non-molded portion of the container so that the non-molded portion of the container is uniformly drawn into the molded portion of the container when the sheet is thermoformed, the deviation or distortion of the partially printed portion is reduced. Generation can be further reduced.
[0013]
The partial printing on the thermoplastic resin film includes, for example, one in which the entire design pattern or single color pattern is printed on the entire surface, and the partial printing portion such as a character display portion or other product name is printed. It is not limited to this aspect.
[0014]
The container molding sheet of the present invention is a long thermoplastic resin sheet in which a plurality of container molding portions 3 are adjacently arranged in a grid shape in the width direction and / or the longitudinal direction .
In the container-forming sheet of the present invention, “a plurality of container-forming parts 3 are adjacent ” means that the container-forming parts 3 are positioned on the sheet at a predetermined interval as shown in FIG. The state, or the state in which the container forming parts 3 are located on the sheet in point contact with each other on the virtual line in the width direction and / or the longitudinal direction connecting the centers of the container forming parts . It should be noted that the container forming portions 3 may be positioned on the sheet at a predetermined interval because the effect of drawing the sheet into the container forming portion in the portion other than the container forming portion can be expected during thermoforming. Preferably, the interval between the container forming parts 3 located on the width direction and / or longitudinal imaginary line connecting the centers of the circular container forming parts on the sheet is approximately 1.5 to 6 cm, preferably 2. 5-5 cm.
[0015]
Further, in the container forming sheet of the present invention, the plurality of container forming portions 3 arranged in a lattice shape are arranged substantially linearly in the width direction and the longitudinal direction as shown in FIG. As described in Japanese Patent No. 27170, a container forming portion in the vicinity of the center portion of the sheet width that is delayed in feeding at the time of thermoforming is formed in advance in the feeding direction, and a container forming portion in the vicinity of both ends of the sheet width Is generally delayed in advance in the feeding direction from the container forming portion in the vicinity of the central portion, and in this case, the lattice arrangement on the container forming sheets of the plurality of container forming portions is visually disturbed. However, a plurality of container forming portions are arranged on a curved line that is slightly bent in the width direction.
[0016]
When a container is manufactured from a container forming sheet by a known thermoforming method such as a matched mold forming method, a dish-shaped product or a molding with a large drawing ratio, which is the ratio of the diameter of the upper surface opening of the container to the depth of the container In the case of goods, there is almost no deviation or distortion of the design pattern or character display part. However, in the case of a bowl-shaped or vertical cup-shaped container having a small drawing ratio and a large rising angle of the side wall, a shift or distortion of the design pattern or the character display portion, and its variation are remarkably exhibited.
Therefore, the container according to the present invention has a drawing ratio (L / D) which is a ratio of the upper surface opening diameter (L) and the side wall height (container depth) (D) of 0.8 to 3, preferably Is from 0.9 to 2.5, more preferably from 1.3 to 2.3.
[0017]
Next, a method for forming a container according to the present invention will be described.
A method of forming a container using the above-described container forming sheet of the present invention is formed by a thermoforming method known per se. That is, when forming a container having a relatively small drawing ratio, such as a ridge shape, in which a partial printing portion is formed by a thermoforming method such as a matched mold forming method from a container forming sheet having a partial printing portion, a plurality of container forming portions In a container molding sheet in which 3 are adjacently arranged in a grid in the width direction and / or the longitudinal direction , on the imaginary line in the width direction and / or the longitudinal direction connecting the centers of the circular container molding portions of the circular container molding portions In addition, at least both end portions in the width direction of the container forming sheet S on which the partial printing portion 4 that is a pattern or character display portion is formed are clamped and molded by a molding die to form the partial printing portion 4. A plurality of containers are molded simultaneously.
[0018]
In the above molding method, as described above, both the width direction both ends and the length direction both ends (portions corresponding to the upstream end and the downstream end of the mold) of the container forming sheet S are clamped, and the container Clamping the peripheral edge of the molded part 3 with a strength within a range that does not reduce the lip strength of the container is preferable for further suppressing the occurrence of deviation and distortion of the partially printed part and the variation thereof. Here, clamping with a strength within a range where the lip strength of the container does not decrease refers to a state in which the peripheral edge of the container molding portion 3 is slightly pulled in during molding. If it clamps strongly so that the peripheral part of the container shaping | molding part 3 may not be drawn in at the time of shaping | molding, there exists a possibility that the lip | rip part intensity | strength of a molded product may fall.
[0019]
FIG. 2 is a schematic view for explaining a container forming process according to the present invention. In FIG. 2, the container forming sheet S is heated and softened in a heating furnace 11 and supplied to a forming die 10 composed of a female die 101 and a male die 102 to be formed into a predetermined container shape, and a plurality of containers are connected. A molded product sheet is obtained. Then, the molded product sheet is trimmed to obtain individual predetermined containers as shown in FIG.
[0020]
The container molding sheet is described in the case of using a container molding sheet, which is a laminated sheet in which a thermoplastic resin film having a partially printed portion is laminated on one surface of a thermoplastic resin foam sheet. Molded in the same way when using a laminated sheet in which a thermoplastic resin film with a partially printed part is laminated on one side of a thermoplastic resin foam sheet and a non-foamed resin sheet is laminated on the other side can do. Moreover, it can shape | mold similarly even if it uses the single layer thermoplastic resin non-foamed sheet and thermoplastic resin foam sheet in which the partial printing part was formed.
[0021]
As the thermoplastic resin foam sheet of the container molding sheet in the present invention, a polystyrene resin foam sheet is mainly used, but other examples include a polyolefin resin foam sheet such as a polypropylene resin. The foamed sheet usually has a foaming ratio of about 1.5 to 15 times, preferably 5 to 12 times.
Examples of the material of the thermoplastic resin film on which printing is performed include polystyrene resins such as polystyrene and high impact polystyrene, other polyolefin resins such as polyethylene resins and polypropylene resins, and polyester resins such as polyethylene terephthalate. . In addition, as the thermoplastic resin film, a stretched or unstretched film can be used, but a stretched film is particularly preferable for achieving the intended purpose of the present invention. Moreover, the thickness of this thermoplastic resin film is about 10-250 micrometers, Preferably it is 10-80 micrometers, More preferably, it is 15-40 micrometers.
[0022]
The thickness of the container forming sheet used in the present invention is the same as that used in container forming by conventional known thermoforming methods such as vacuum forming method, pressure forming method, matched mold forming method, Generally, a thermoplastic resin foam sheet or a thermoplastic resin foam sheet laminated with a thermoplastic resin film is 0.5 to 5 mm, preferably 0.7 to 4 mm. The thickness is 0.2 to 2.5 mm, preferably 0.3 to 0.8 mm.
[0023]
【The invention's effect】
As described above, each of the circular container molding parts is a portion having a large elongation rate at the time of molding in the container molding sheet in which a plurality of container molding parts are adjacently arranged in a grid shape in the width direction and / or the longitudinal direction. By using a container molding sheet that is partially provided with a pattern and a character display portion on the imaginary line in the width direction and / or the longitudinal direction connecting the centers of the circular container molding parts , the appearance is good, It is possible to obtain a container having a bowl shape or the like having a relatively small aperture ratio in which a design pattern or a character display part is partially formed, with a shift or distortion of the design pattern or the character display part or variation thereof being partially improved.
[Brief description of the drawings]
FIG. 1 shows a partially cutaway plan view of a container forming sheet of the present invention. FIG. 2 shows a conceptual diagram of a container forming process. FIG. 3 shows a container of the present invention.
S: sheet for container molding 1 ... thermoplastic resin foam sheet 2 ... printing thermoplastic resin film 3 ... container molding part 4 ... partial printing part 10 ... molding die 101 ... female die 102 ... male die 11 ... Heating furnace

Claims (3)

In the thermoplastic resin long sheet in which a plurality of circular container molded portions are adjacently arranged in a grid pattern in the width direction and the longitudinal direction , each circular container molded portion has a width direction connecting the centers of the respective circular container molded portions and A thermoplastic resin sheet for forming a container, wherein a pattern or a character display part is partially formed on a virtual line in the longitudinal direction. 2. The container molding thermoplastic resin sheet according to claim 1, wherein the thermoplastic resin sheet for container molding is obtained by laminating a thermoplastic resin film partially having a design pattern or a character display portion on a polystyrene resin foam sheet. Thermoplastic resin sheet. A ratio (L / D) of the container upper surface opening diameter (L) and the container side wall height (container depth) (D) formed by thermoforming the thermoplastic resin sheet for container formation according to claim 1 or 2. Is a container in which a pattern or a character display part is partially formed.

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