JP4374937B2 - Molded body with foamed in-mold label that forms uneven patterns - Google Patents

Description

  The present invention relates to a molded body with a foamed in-mold label that forms a concavo-convex pattern at a predetermined surface position.

  Conventionally, in injection molding or hollow molding, an in-mold label is inserted into a mold in advance, and the molded body is molded at the same time that the in-mold label is heat-sealed to the molded body. However, it was generally known.

  However, in the above-described conventional molded body with an in-mold label, the main material of the in-mold label is paper or a synthetic resin film. For this reason, when providing a concavo-convex pattern on the surface of the in-mold label, there is a limit to the height of lifting, and it has been difficult to obtain a high design property. As shown in Table 1, in the case of a normal paper label, the height that can be lifted was 1 mm or less, the mold reproducibility was poor, and the cosmetics were inferior. In the case of a normal synthetic resin film label, the height that can be lifted is 2 mm or less, and the cosmetics are better than paper labels, but the heat resistance during molding is poor, and the temperature of the molten resin Sometimes it was torn under pressure. Although a heat resistant resin can be used, in this case, the manufacturing cost becomes very expensive.

  The present invention solves the problems of the above-described conventional molded body with an in-mold label, has a reproducibility to a mold, and has a foam in-mold label that forms an uneven pattern with high designability at a predetermined surface position. A molded body is provided.

That is, the first invention of the present invention forms an uneven pattern in a mold from an unfoamed in-mold label whose main layer is a post-foamed paper, which is a paper in which thermally foamable microcapsules are dispersed in advance. At the same time as inserting into a predetermined position on the cavity surface and molding the molded body, the in-mold label is thermally fused and foamed to the molded body to develop a concavo-convex pattern at a predetermined surface position of the foamed in-mold label. It is a molded body with a foam in-mold label which forms the uneven | corrugated pattern characterized by the above-mentioned.

  Next, according to a second aspect of the present invention, the post-foamed paper is dried so as not to foam the thermally foamable microcapsules to be mixed when the paper is made, and the natural fiber content is 51% of solid content. The molded body with a foamed in-mold label for forming a concavo-convex pattern according to the first invention, characterized by being at least wt% and having a foaming start temperature not higher than the molding temperature.

  The molded body with a foamed in-mold label forming the uneven pattern according to the present invention is a post-foamed paper in which the main layer of the unfoamed in-mold label used contains thermally foamable microcapsules, and the molded body is molded in a mold. At the same time as molding, an unfoamed in-mold label is heat-sealed and foamed on the molded body, and as a result, the reproducibility of the uneven pattern on the cavity surface of the mold is good, and the surface of the foamed in-mold label is An uneven pattern with high designability can be formed.

  Moreover, the foamed in-mold-labeled molded body forming the uneven pattern of the present invention has a natural fiber content of 51% by weight or more in the foamed in-mold label, has good heat resistance during molding, and has good disposal properties. Moreover, heat insulation is favorable by the foaming effect.

  Next, an embodiment of the molded body with a foamed in-mold label for forming the concavo-convex pattern of the present invention will be described.

  The molding method of the molded body with a foam in-mold label for forming the concavo-convex pattern of the present invention is as follows. First, the surface layer is formed in a predetermined position on the cavity surface for forming the concavo-convex pattern in the mold such as injection molding or hollow molding. Is the secondary processing layer (varnish coating layer, printing layer, resin layer, etc.), the main layer is the post-foamed paper layer, the back layer is the unfoamed in-mold label with the adhesive resin layer, and the surface is the cavity surface Are attached by temporary adhesion by electrostatic method, adhesive method, vacuum method, etc., and then molds are clamped and molded products such as containers are molded with molten resin, and at the same time, in-mold labels are molded The foamed paper layer is foamed after the main layer of the in-mold label by the heat of the molded body at this time, and the uneven pattern of the mold is formed at a predetermined surface position of the foamed in-mold label. Of the cavity surface It is intended to express.

  As the post-foamed paper used for the main layer of the above-mentioned unfoamed in-mold label, there are a mixed paper type and an impregnated type, and the mixed foam type post-foamed paper is a thermally foamable microcapsule that is mixed when paper is made. The impregnated post-foamed paper is a compound of a paper with low interlaminar strength mixed with thermally foamable microcapsules and a thermoplastic resin that connects the paper fibers and the capsules. And dried so as not to foam. In both types of post-foamed paper, the natural fiber content is 51% by weight or more of the solid content, and the foaming start temperature is made below the molding temperature.

First, a mixed paper type post-foamed paper (100 g / m ² ) containing 20% by weight of thermally foamable microcapsules was prepared, and then an ethylene / vinyl acetate copolymer hot melt adhesive resin was applied to the back of the foamed paper at 25 μm. After coating with a thickness and extruding a linear low density polyethylene with a thickness of 15 μm on the surface, the surface is corona-treated to print characters and patterns, and the surface has good releasability from the mold. A peeling varnish containing silicon for coating was applied. Then, it is punched into a predetermined label shape, and the [surface side] varnish layer (110) / printing layer (120) / polyethylene film layer (130) / post-foamed paper layer (140) / adhesive resin layer (150) shown in FIG. [Back side] An unfoamed in-mold label (100a) having a configuration was prepared.

  Next, the above-mentioned unfoamed in-mold label (100a) shown in FIG. 1 (a) is formed into a 3 mm-diameter dot-like concave pattern (211) of an injection mold (200) opened on an injection molding machine. As shown in FIG. 1 (b), it is temporarily bonded by an electrostatic method and inserted into the cavity surface (210) formed with a die, and the mold is clamped to enter the cavity at 220 ° C. from the gate. The molded polypropylene (300) shown in FIG. 1 (c) is molded by injecting polypropylene melted at the molding temperature, and at the same time, the in-mold label is thermally fused to the surface of the molded body. The foamed thermally foamable microcapsules dispersed in the foamed paper after the main layer of the in-mold label are foamed, and the surface of the foamed in-mold label fills the concave pattern formed on the cavity surface of the mold by the expansion force. This foam immo A foamed in-mold label (100b) that forms a convex pattern at a predetermined surface position of the mold label and is released from the mold that is opened to form the convex pattern (101) of this embodiment shown in FIG. ) A molded body (400) was produced. It should be noted that the depth of the 3 mm diameter dot-like concave pattern formed on the mold cavity surface was changed to examine how much the foamed in-mold label could enter.

  For the molded product with foamed in-mold label that forms the convex pattern produced, the raised height of the convex pattern of the foamed in-mold label, cosmetics, disposability, reproducibility of the concave pattern of the mold, The heat resistance and the heat insulating effect of the label were evaluated. The results are listed in Table 1.

As shown in Table 1, when the main layer of this example used an in-mold label of post-foamed paper, the in-mold label of the in-mold label was compared with the case of an ordinary paper label or an ordinary synthetic resin film label. The raised height of the convex pattern was as high as 5 mm or less, and the reproducibility of the concave pattern of the mold was good. As a result, the cosmetics were good. Further, since the natural fiber content is 51% by weight or more of the solid content, the heat resistance during molding is good and the discardability is also good. Furthermore, the foamed in-mold label had a very good heat insulating effect that could not be obtained with a normal paper label or a normal synthetic resin film label.

It is explanatory drawing which shows the shaping | molding process of the molded object with a foam in-mold label which forms the concave shape pattern of an Example, (a) is an unfoamed in-mold label, (b) is an unfoamed in-mold label. A mold inserted into the tee surface, (c), is a molded body with a foamed in-mold label that forms an uneven pattern. It is explanatory drawing which shows the structure of the unfoamed in-mold label which concerns on an Example.

Explanation of symbols

100a: Unfoamed in-mold label 100b ... Foamed in-mold label 101 ... Convex pattern 110 ... Varnish layer 120 ... Print layer 130 ... Polyethylene film layer 140 ... Post-foamed paper layer 150 ... Adhesiveness Resin layer 200 ... Injection mold 210 ... Cavity surface 211 ... Concave pattern 300 ... Molded body 400 ... Molded body with in-mold label

Claims (2)

  In advance, an unfoamed in-mold label having a foamed paper as a main layer, which is a paper in which thermally foamable microcapsules are dispersed, is inserted into a predetermined position on the cavity surface that forms the uneven pattern in the mold, At the same time that the molded body is molded, the in-mold label is heat-sealed and foamed to the molded body to form a concavo-convex pattern characterized in that a concavo-convex pattern is expressed at a predetermined surface position of the foamed in-mold label. Molded body with foam in-mold label.   The post-foamed paper is dried so as not to foam the heat-foamable microcapsules to be mixed when paper is made, and the natural fiber content is 51% by weight or more of the solid content, and the foaming start temperature is the molding temperature. The molded body with a foamed in-mold label that forms the uneven pattern according to claim 1, wherein: