JP2008030795A - Synthetic resin-made container with in-mold label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an air dune from forming between an inflating parison or preform and a label and to effectively suppress formation of a sink mark caused by label attachment even if a trunk has a thin wall thickness in a blow molding process of attaching the label by an in-mold method. <P>SOLUTION: A synthetic resin-made container with an in-mold label is made by blow molding. Two sheets of labels each having a width approximately equal to and less than the half of the outer peripheral length of the cylindrical trunk of a container body are attached by in-mold molding to the trunk to cover almost its entire periphery in a range where the side end parts of two labels do not overlap each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a synthetic resin container with an in-mold label by blow molding, in which a label is attached by an in-mold method over substantially the entire circumference of the outer peripheral surface of a body portion.

  As a means to achieve the display of decorative patterns and product names and explanations on the surface of synthetic resin blow-molded containers, a label printed with decorative patterns or product names and explanations on the surface is placed on the body surface of the container body. Many means of sticking are used.

  And as one method of sticking the label, the label is inserted into the mold in advance, and so-called the in-mold sticking to the body surface of the blow molded container body at the same time as the blow molding of the container body There is an in-mold method.

  This in-mold method achieves label sticking to the container body at the same time as the blow molding of the container body, and does not require a separate separate process of sticking work, between the surface of the container body and the in-mold label. Since there is no step, there is no risk of deterioration of the appearance and feel of the container due to this step, and the in-mold label is securely and stably attached to the container body regardless of the thinness of the container body. It exhibits an excellent effect that it can be obtained.

Moreover, in this in-mold method, since the sticking of the label to the container body is strong and stable, it is wound and stuck over the entire circumference of the outer peripheral surface of the trunk (for example, Patent Document 1). (Refer to) The display function range is expanded well, and in some cases, the container body is mechanically reinforced with a label, or the label is provided with a light-shielding property or oxygen barrier property. And oxygen barrier properties can be easily provided.
JP-A-5-338018

  However, the method according to Patent Document 1 requires an apparatus and a process for reproducing a label in a cylindrical shape in a mold, which is not necessary for a normal in-mold method. Further, when winding and sticking over the entire circumference of the outer peripheral surface of the body portion of the container by the in-mold method, in particular, when the body portion is cylindrical, for example, unlike the case of an elliptical cylindrical body, it expands. The blow molding proceeds while the parison and preform are almost simultaneously in contact with the label surface over almost the entire circumference, so the air loses a place to escape, air pools and bubbles are generated, and the appearance of the label is impaired. A problem occurs.

  Therefore, the present invention was created to solve the above-described problems, and in blow molding in which a label is stuck by an in-mold method, it can be carried out in a normal process, and a parison or preform that expands and a label It is an object to prevent the formation of sink marks due to sticking of a label even when the body portion is thin, so that no air pool is formed between them.

Among the present invention for solving the above technical problems, the means of the invention according to claim 1 is:
In a synthetic resin container with an in-mold label by blow molding,
Two labels made of a paper base material having a width that does not exceed half of the outer peripheral length of the cylindrical body portion of the container main body, as long as the side edges of the two labels do not overlap. In addition, it is adhered by the in-mold method over substantially the entire circumference of the body part.

  According to the above configuration of claim 1, since the label of the paper base material has excellent air permeability, air constrained between the inflating parison or preform and the label is transmitted through the label to the outside. It is possible to escape and to effectively prevent air accumulation and bubbles. Such a breathability cannot be expected with a label made of a synthetic resin film.

  In addition, since two labels having a width that does not exceed half of the outer perimeter of the body portion are combined and the label is pasted by the in-mold method, the width of the label is the circumference of the body mold surface of each split mold Thus, the label can be held by each split mold without protruding from the range of the barrel mold surface of the split mold.

However, since the container body made of synthetic resin shrinks after molding, the label of the paper base material hardly shrinks. Therefore, the label is affixed to the circumferential direction of the trunk wall at the butt portion of the label. Shrinkage occurs, and at this portion, the body wall is deformed from an arc shape to a concave shape, and the body portion is depressed, so-called sink is generated.
And the generation | occurrence | production of this sink becomes remarkable, so that the trunk | drum thickness of a container main body becomes thin.

  Therefore, in the configuration according to claim 1, two labels that are close to half, that is, substantially half the width, are combined and pasted by the in-mold method within a range not exceeding half of the outer peripheral length of the body portion. Thus, this gap is made as small as possible so that the side edges of the two labels do not overlap, and the shrinkage in the circumferential direction of the body portion in the vicinity of the butt portion is limited to reduce the occurrence of sink marks in the vicinity of the butt portion. It is possible to provide a container that can be surely suppressed and that has a label with a beautiful exterior covering substantially the entire circumference of the body. Moreover, since a label is affixed over the substantially perimeter of a trunk | drum, a display area becomes large and the amount of information provision can be increased.

  According to a second aspect of the present invention, in the first aspect of the present invention, the gap between the butted portions of the two labels is in the range of 0 to 2.0 mm.

  The above configuration of claim 2 shows a design standard for how much the gap of the butt portion of the label is allowed, and the gap of the butt portion can suppress the occurrence of small sink marks. According to the configuration described in Item 2, when the gap between the butting portions is 2 mm or less, the occurrence of sink marks in the vicinity of the butting portion of the label can be suppressed to an extent that cannot be detected by appearance.

  The invention means of claim 3 resides in that, in the invention of claim 1 or 2, the width of one label is 0.95 to 1.0 times half of the outer peripheral length of the body portion.

The said structure of Claim 3 shows the design standard about how much the width of a label is made into the range, and the width of a label is 0.95 or more of the half of the outer peripheral length of a trunk | drum, and By doing so, the gap between the butted portions can be made sufficiently small to reliably suppress the occurrence of sink marks in the vicinity of the butted portion.
Also, when the ratio is 1.0 times or more, if the label is set to the split mold even a little, it will protrude from the mold surface and may be pinched when the mold is opened or closed, or part of the side edges of the two labels may overlap. Therefore, the upper limit is preferably 1.0 times.

  According to a fourth aspect of the present invention, in the invention of the first, second, or third aspect, a rib is provided around at least one of the barrel height positions immediately above or directly below the label.

  According to the above configuration of the present invention, since the rib rib rib functions as a reinforcing rib, the mechanical strength of the barrel can be increased, and even if the barrel of the container body is thin, the shrinkage of the container barrel Can be suppressed, and the occurrence of sink marks in the vicinity of the abutting portion can be more effectively suppressed.

Since the present invention has the above-described configuration, the following effects can be obtained.
In the invention according to claim 1, since the paper base label has excellent air permeability, air constrained between the expanding parison or preform and the label is allowed to permeate through the label. It can escape to the outside, and can effectively prevent air accumulation and bubbles.

  In addition, by combining two labels made of a paper base material having a substantially half width within a range not exceeding half of the outer peripheral length of the body portion, the two label sides are bonded by in-mold molding. As long as the edges do not overlap, the gap between the label abutting portions can be reduced, and the occurrence of sink marks in the vicinity of the abutting portion can be reliably suppressed, and the label extends over the entire circumference of the barrel portion. Can provide a beautifully packaged container. Since the label is attached over substantially the entire circumference of the trunk, the display area can be increased and the amount of information provided can be increased.

  In invention of Claim 2, it shows the design standard about how much the clearance gap of a label butt | matching part is accept | permitted, By making this clearance | interval 2 mm or less, in the butt | matching part vicinity of a label The occurrence of sink marks can be suppressed to an extent that cannot be detected by appearance.

  In invention of Claim 3, the design standard about how much the width of a label is made into a range is shown, and the width of a label is 0.95 or more of half of the perimeter length of a body part. By setting it as the range, it is possible to sufficiently reduce the gap between the butted portions and reliably suppress the occurrence of sink marks in the vicinity of the butted portion. Also, when the ratio is 1.0 times or more, if the label is set to the split mold even a little, it will protrude from the mold surface and may be pinched when the mold is opened or closed, or part of the side edges of the two labels may overlap. Therefore, the upper limit is preferably 1.0 times.

  In the invention according to claim 4, since the protruding rib rib functions as a reinforcing rib, the mechanical strength of the barrel can be increased, and even if the barrel of the container body is thin, the container body barrel It is possible to suppress deformation accompanying the shrinkage of the film, and to more effectively suppress the occurrence of sink marks in the vicinity of the butt portion.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of the container of the present invention, FIG. 1 is a perspective view, FIG. 2 is a half longitudinal sectional view, and FIG. 3 is taken along the line AA in FIG. FIG.

  This container has a lower end closed with a bottom 6 that is slightly inwardly recessed in a spherical arc shape, and a shoulder that forms an inner flange-shaped reduced diameter step at the upper end of the body 4 formed into a straight cylindrical shape. 3 is a blow molded product made of high-density polyethylene resin, in which a cylindrical mouth tube portion 2 having a diameter slightly smaller than that of the body portion 4 and having a screw thread engraved on the outer peripheral surface thereof is connected. The container body 1 and two labels 7 coated and adhered to the outer peripheral surface of the body part 4 of the container body 1 by an in-mold method.

  Further, the container body 1 is provided with ridge circumferential ribs 5 covering the upper and lower end surfaces of the label 7 at the upper end portion and the lower end portion of the body portion 4. The outer peripheral length of the body 4 of the container body 1 is 147 mm, the total height is 143 mm, and the average thickness of the body 4 is 0.8 mm.

The two labels 7 to be adhered to the outer peripheral surface over the entire height between the upper and lower protruding peripheral ribs 5 of the body portion 4 are obtained by performing offset printing on the surface of a paper base material and applying a varnish coat. A heat-sensitive adhesive is applied to the back surface and has dimensions of 117 mm in length and 73 mm in width (corresponding to 0.99 times the outer peripheral length of the body part 4 of the container body 1). It is.
And the sticking form with respect to the outer peripheral surface of the trunk | drum 4 of the label 7 of two sheets is as shown in FIG. 2, and the average of the clearance gap of the butt | matching part 7b is about 0.5 mm.

  In addition, when an overlap occurs between the edge portions of the two labels 7, peeling easily occurs at the edge portion of the label 7 outside the overlap portion, and the appearance of the container is impaired. In addition, the possibility that this peeling will develop into peeling from the body 4 of the label 7 is very high.

  FIG. 5 and FIG. 6 are for schematically explaining the process of extrusion blow molding the container of this embodiment using a pair of split molds 11, FIG. 5 is a longitudinal sectional view, and FIG. 5 is a plan sectional view taken along line BB in FIG.

  In blow molding, first, the two labels 7 are placed on the body forming mold surfaces 12 of the pair of split molds 11 opened, and the side edges of the labels 7 are the respective body forming mold surfaces. The vacuum hole 13 holds the vacuum while being positioned by a robot or the like so as to be aligned with the side edge of 12. When the mold is closed, a slight gap is formed in the abutting portion 16 of both labels 7 as shown in FIG.

  Next, the parison P extruded from an extruder (not shown) is sandwiched between the pinch-off portions 14 by the both molds 12 and a blow jig 15 is assembled from above, and the sandwiched parison P is attached to the container body 1. Blow molding.

  Here, when the body 4 is cylindrical, unlike the case of an elliptical cylinder, for example, substantially the entire circumference of the parison P that expands and deforms comes into contact with the label 7 almost simultaneously, and between the parison P and the label 7. The air escape place is lost and trapped between the inflated and deformed parison P and the label 7. Since the base material of the label 7 is made of paper having air permeability, the air is removed from the label 7. Then, it can escape from the vacuum hole 13 to the outside.

  Note that the label 7 and the blow-molded body 4 can be adhered by heat-bonding or thermocompression bonding with a blow-molding pressure when the heat-sensitive adhesive of the label is softened by the heat of the parison P. it can.

  In the synthetic resin container with an in-mold label of this example shown in FIGS. 1 to 3 obtained in this way, the label 7 has no air accumulation, and extends over substantially the entire circumference of the body part 4. It became a beautiful exterior. In addition, since the label is attached over substantially the entire circumference of the body portion, the display area is increased and the amount of information provided can be increased. In addition, by making the gap between the butting portions 7b extremely small, the deformation of the container main body 1 at this portion, that is, the occurrence of so-called sinks, can be suppressed to an extent where it cannot be visually detected.

Moreover, in the container of the present embodiment, since the protruding rib ribs 5 function as reinforcing ribs, even if the body part 4 is thin, deformation of the body part 4 can be suppressed, and a stable self-shape as a container. The holding ability is exhibited, and in particular, the occurrence of sink marks at the abutting portion 7b can be reduced more reliably.
Moreover, since the adjacent attitude | position of container main bodies 1 is constant, while the handling state of storage of container main body 1 or sliding conveyance becomes favorable, the label 7 stuck on the outer peripheral surface of the trunk | drum 4 at the time of this handling, It is possible to prevent the delirium from coming into contact with other articles.

  FIG. 4 is a cross-sectional plan view similar to FIG. 3 for a comparative example in which the gap between the butting portions 7b is increased. This comparative example is an example using a label 7 having a lateral width of 65 mm (corresponding to 0.88 times the outer peripheral length of the barrel part 4 of the container body 1), and the average width of the gap of the butting part 7b is 8. Due to the large thermal shrinkage in the circumferential direction in the vicinity of the butt portion 7b, the arc-shaped body wall has a concave shape with respect to the other parts whose thermal shrinkage is suppressed to a small level by sticking the label 7 on the paper base material. It is in a state where so-called sink marks are generated.

As mentioned above, although the structure of this invention and its effect were demonstrated along the Example, this invention is not limited to this Example.
For example, in the above-described embodiment, an extrusion blow molded container is taken as an example, but the present invention is not limited to blow molding, and can be applied to biaxial stretch blow molding. Moreover, the synthetic resin used for the container body is not limited to high-density polyethylene, and a synthetic resin conventionally used for blow molding can be used.

It is a perspective view which shows one Example of the container of this invention. It is a semi-longitudinal sectional view of the container of FIG. FIG. 3 is a cross-sectional plan view taken along line AA in FIG. 2. FIG. 4 is a plan cross-sectional view similar to FIG. 3 for a comparative example in which a gap between butt portions is increased. It is a schematic explanatory drawing which longitudinally shows the blow molding process of the container of this invention. It is a schematic explanatory drawing shown by the plane cross section along the BB line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Container body 2; Mouth part 3; Shoulder part 4; Body part 5; Projection rib 6; Bottom part 7; Label 7b; Butt part 11; Split mold 12; ; Pinch-off part 15; Blow jig P; Parison

Claims (4)

Two labels (7) made of a paper base material having a width not exceeding half of the outer circumference of the cylindrical body (4) of the cylindrical body (1) of the container body (1) A synthetic resin container with an in-mold label by blow molding, which is adhered by an in-mold method over substantially the entire circumference of the body (4) within a range in which the side ends of (7) do not overlap. The synthetic resin container with an in-mold label according to claim 1, wherein the gap between the butted portions of the two labels (7) is in the range of 0 to 2.0 mm. The synthetic resin container with an in-mold label according to claim 1 or 2, wherein the width of one label (7) is 0.95 to 1.0 times half of the outer peripheral length of the body (4). The synthetic resin container with an in-mold label according to claim 1, 2 or 3, further comprising a rib peripheral rib (5) provided at least at one of the height positions immediately above or directly below the label (7).

Images