JP2884174B2 - Manufacturing method of hollow molded products - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a resin hollow molded article to which a label on which characters, symbols, patterns, and the like are written is attached.

[Prior Art] Conventionally, a label with an adhesive has been generally applied to the surface of a hollow molded article.

[Problem to be Solved by the Invention] When a label with an adhesive is applied to the front surface of a hollow molded article by applying pressure evenly over the entire surface, the label remains flat for a short period immediately after the application. Over a period of several days, partial expansion failure due to air bubbles and partial peeling failure of the label occur due to various causes such as shrinkage and extension of the label, deformation of the label attaching surface of the case, etc. There was a problem.

In view of the problems described above, the present invention forms a smooth surface for labeling at the time of blow molding on a hollow molded product formed by blow molding, and a large number of fine lines on the smooth surface for labeling. By developing a new method of forming a mark and attaching a label to the surface, it eliminates the above-mentioned problems associated with the deformation and distortion of the label and the smooth surface for attaching the label of the hollow molded product after the label is attached. With
Prevent the occurrence of a defective state in which the pressure-sensitive adhesive label stuck to the label-attached smooth surface of the hollow molded product after blow molding partially swells over time, or also peels partially. It is an object of the present invention to provide a method for producing a hollow molded article that can be prevented.

[Means for Solving the Problems] The present invention employs the following manufacturing method as technical means for achieving the above object. That is, the plasticized resin parison is extruded between the divided molds, and then the mold is closed and a pressurized fluid is injected into the paris to expand the paris, thereby forming a smooth surface provided on the cavity surface of the mold. Blow molding step for molding a hollow molded article having a smooth surface for label application formed by a part, a label for forming many fine streaks on the smooth surface for label application of the hollow molded article molded by the blow molding step A method for producing a hollow molded article, which comprises sequentially performing, in order, a labeling step of attaching a lalevel to a smooth surface for labeling after the labeling pretreatment step and the labeling pretreatment step.

[Operation] According to the method of manufacturing a hollow molded product according to the present invention, a smooth surface for label application is formed on the hollow molded product, and many fine streaks are formed on the smooth surface for label application. Therefore, even if the label is applied to the label-attaching smooth surface, a fine gap is formed between the label and the surface of the hollow molded article, and furthermore, air or gas that passes outside from the outer peripheral edge of the label is formed. Is secured over the entire surface.

For this reason, even after the label is pasted, even if the label and the smooth surface for label pasting of the hollow molded article are deformed and deformed, air is partially taken in from the outside, or gas is generated from the label or the smooth surface for pasting the label. The air and gas are dispersed over the entire surface without concentrating at one place, and escape to the outside through streaks extending outward from the outer peripheral edge of the label. The occurrence of a defect such as swelling or partial peeling is prevented beforehand.

Example An example of a method for manufacturing a hollow molded product according to the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1, 1 denotes a split mold for blow molding, and cavities 2, 2 for forming a hollow molded product of the mold 1, 1 are provided on the outer surface of a case member. And a slightly protruding smooth surface forming portion 3 for forming a flat surface for label application in a depressed shape.

In order to blow-mold a hollow molded product using the divided molds 1, 1, as shown in FIG. 1, a polyolefin resin plasticized from the extrusion head 4 is interposed between the opened molds 1, 1. The parison 5 is extruded and arranged, and then, as shown in FIG. 2, the molds 1 and 1 are closed, and a pressurized fluid is pressed into the paris 5 to expand the paris 5 and the molds 1 and 1 are closed. A hollow double-walled case member 6 which is a hollow molded product is formed by the cavities 2 and 2, and a smooth surface 7 for label application is formed in a depressed shape by the smooth surface forming portion 3 slightly protruding from the outer surface thereof. . The label attaching smooth surface 7 is formed slightly larger than the label to be attached.

As shown in FIG. 3, a large number of fine streaks 8 are formed on the smooth surface 7 for sticking the label on the hollow double-walled case member 6 formed by the blow molding process as described above. A pre-labeling process is performed. In this labeling pretreatment step, a number of acute angled fine grooves are formed by friction with sandpaper, a metal brush or the like.

Next, as shown in FIG. 4, a label attaching step of attaching a label 9 with an adhesive is performed on the smooth surface 7 for label attaching that has undergone the above-described label applying pretreatment step, and as shown in FIG. A hollow double-walled case 10 having a predetermined label 9 attached to the outer surface of the case is obtained.

The label 9 is, for example, formed by forming a pressure-sensitive adhesive layer or an adhesive layer on the back surface of a substrate made of plastic or paper, and the resin constituting the hollow double-walled case 10 is made of polyethylene, polypropylene, or the like. Polyolefin resin, polyamide resin, polyvinyl chloride resin, AB
A material suitable for blow molding, such as S resin, is used.

In the present embodiment, when the hollow double-walled case member 6 is blow-molded, the label-attaching smooth surface 7 is formed in a depressed shape, but the label-attaching smooth surface 7 is not necessarily formed in a depressed shape. Good.

As described above, in the hollow double-walled case 10 manufactured through the blow molding step, the label applying pre-processing step, and the label applying step shown as the examples, the label applying smooth surface 7 slightly larger than the label 9 is used. Since many fine streaks 8 are formed on the smooth surface 7 for attaching a label, even if the label 9 with an adhesive is affixed to the smooth surface 7 for applying a label, the surface of the flat surface 7 is not damaged. A fine gap is formed between the adhesive layer 7 and the adhesive layer, and a fine passage of air or gas passing outward from the outer peripheral edge of the label 9 is secured over the entire surface by the numerous streaks 8. You. For this reason, after label attachment, deformation | transformation distortion arises in the label attachment smooth surface 7 of the case member 6, and the label 9, and air is partially taken in from the outside, the label 9, its adhesive layer or the label attachment smooth surface. Even if gas is generated from 7, the air and gas are dispersed over the entire surface without concentrating at one place, and the air and the gas are discharged to the outside through the streak marks 8 that extend outward from the outer peripheral edge of the label 9. Since the label 9 escapes, it is possible to prevent the occurrence of a defect such that the label 9 partially swells or partially peels off after the label 9 is attached.

In addition, in order to maintain the smoothness of the applied label and prevent the occurrence of defects after the label is applied, a number of concave fine streaks having a depth substantially equal to the thickness of the pressure-sensitive adhesive layer of the label are formed. Is preferred.

 Examples will be described below.

As a hollow molded product, a high-density polyethylene hollow double-walled case member (average resin thickness of 3.5 mm after blow molding) was molded in the directions shown in FIGS. Two hours after the product was taken out of the mold, fine streaks (average depth of about 30 μ) were formed on the hollow double-walled case members of ten samples with sandpaper. And polyester base sheet (200μ thick)
A printing ink layer is formed on the surface of the base sheet, and the surface is covered with a transparent skin layer of polyester (thickness: 25μ). After sticking to the formed surface, the label was allowed to stand for 5 days, and the label was observed, but no swelling of the label was confirmed for all 10 samples.

As a comparative example, for the remaining 10 samples, the label was affixed without passing through a pre-labeling pretreatment process, and then left for 5 days to observe the label. In 9 samples, poor swelling of the label was confirmed. .

The present invention is characterized in that the respective steps of a blow molding step, a pretreatment step for labeling and a labeling step are sequentially performed.

By the way, the labeling pretreatment step was omitted, and as an alternative, an attempt was made to integrally form fine streaks during blow molding. However, the reproducibility of the mold cavity was limited in blow molding. In addition, frame processing was also attempted as a pre-labeling process, but the bulging of the label over time was not eliminated by the frame processing.

[Effects of the Invention] The method for producing a hollow molded article according to the present invention comprises extruding a plasticized resin Paris between divided molds, closing the molds, and pressurizing a pressurized fluid into the parisons. Is blown to form a hollow molded product having a smooth surface for labeling formed by the smooth surface forming portion provided in the cavity of the mold, for labeling a hollow molded product formed by the blow molding process. Since the labeling pretreatment step of forming many fine streaks on a smooth surface, and the labeling step of sticking a lalevel on a label sticking smooth surface that has undergone the above labeling pretreatment step, the respective steps are sequentially performed. , After the label is applied, the smooth surface for attaching the label of the case member and the partial intake of air from the outside due to the deformation distortion of the label, or
Due to the generation of gas from the label and its sticking smooth surface, etc., the air and gas are dispersed over the entire surface without being concentrated at one place, and from the label sticking smooth surface having many streaks. It can escape to the outside, so that the label attached to the smooth surface for label attachment of the case member after blow molding partially swells with the passage of time,
The effect of preventing the occurrence of a defective state such as partial peeling can be obtained beforehand.

[Brief description of the drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a front view showing an embodiment in which a parison is arranged between divided molds in a blow molding process, and FIG. 2 is a longitudinal sectional view showing an embodiment in which the mold is closed. Fig. 3, Fig. 3 is a perspective view of a part of a hollow double-walled case member showing a label sticking pre-processing step, Fig. 4 is a perspective view of a part of a hollow double-walled case member showing a label sticking step, FIG. 5 is an overall perspective view showing an example of the manufactured hollow double-walled case. 1,1 ... Divided mold, 2,2 ... Cavity, 3 ... Slightly protruding smooth surface forming part for forming a smooth surface for label application, 4 ... Extrusion head, 5 ... Parison, 6 ... ... Case member of hollow double wall, 7 ... Smooth surface for sticking label, 8 ...
Numerous striations, 9 ... Label, 10 ... Hollow double wall case

Claims (1)

(57) [Claims] 1. A plasticized resin parison is extruded between divided molds, and then the mold is closed and a pressurized fluid is injected into the paris to expand the paris, thereby providing a smooth surface provided in the cavity of the mold. A blow molding step for forming a hollow molded article having a smooth surface for labeling formed by the surface forming portion, and a plurality of fine streaks formed on the smooth surface for labeling of the hollow molded article formed by the blow molding step. A method for producing a hollow molded article, comprising sequentially performing a label applying pretreatment step, and a label applying step of applying a label to a label attaching smooth surface that has passed through the label applying pretreatment step.