JP2005028838A - Method for temporary adhesion of in-mold label on mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for temporarily bonding an in-mold label on a predetermined position in the cavity side face of a male or female mold without being comparatively restricted nor needing any special mold for the purpose temporarily bonding the in-mold label to the mold. <P>SOLUTION: This method comprises temporarily bonding an in-mold label 100 having a surface resistivity value of ≥10<SP>13</SP>Ω/cm<SP>2</SP>, by using the electrostatic force of the in-mold label, on a predetermined position in the cavity side surface 210 or 220 of the male mold 200 or female mold of a mold for injection mold opened for injection molding. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an in-mold temporary bonding method for an in-mold label when the in-mold label is inserted into an injection mold for mold opening immediately before molding.

  Conventionally, as a method of sticking a label to a plastic molded product such as a container, in-mold which is heat-sealed with the molded product or has a heat-sealed resin layer on the back surface to eliminate secondary processing (printing) after molding. A method has been adopted in which the label is inserted into an injection mold that is opened just before molding to mold the molded product body, and at the same time, the in-mold label is thermally fused to the molded product body. As a method of temporarily bonding the in-mold label in the mold, for example, when the in-mold label is bonded to the inner surface of the bottom (310) of the cup-shaped container (300) shown in FIGS. 3 (a) and 3 (b). As shown in FIG. 2, a plurality of vacuum holes (211) are provided on the cavity surface (210) forming the bottom inner surface of the male mold (200) of the injection mold, and the suction force of the vacuum holes In general, a vacuum method in which the in-mold label (100) is temporarily bonded to the cavity surface (210) forming the inner surface of the bottom of the male mold has been used.

  However, in the conventional vacuum method, the in-mold label is temporarily attached to the cavity surface of the mold by a vacuum circuit in the male mold or female mold of the injection mold. Therefore, it takes a long time to manufacture the mold, and the cost for manufacturing the mold is high. In particular, in a male mold, a vacuum circuit may not be provided due to a mold structure.

  The present invention solves the problems in the in-mold temporary adhesion method of the conventional in-mold label described above, without requiring a special mold structure for temporarily bonding the in-mold label to the mold, It is an object of the present invention to provide an in-mold temporary bonding method for an in-mold label that can temporarily bond an in-mold label to a predetermined position on a male or female cavity surface without any restrictions.

That is, the first invention of the present invention is an in-mold having a surface specific resistance value of 10 ¹³ Ω / cm ² or more on the cavity surface at a predetermined position of the male mold or female mold of the mold for injection molding. An in-mold temporary bonding method for an in-mold label, wherein the label is temporarily bonded by the electrostatic force of the in-mold label.

Next, according to a second aspect of the present invention, the in-mold label gold according to claim 1, wherein the in-mold label is a polyolefin film having a surface resistivity of 10 ¹³ Ω / cm ² or more. In-mold temporary adhesion method.

Next, the third invention of the present invention is a laminated film in which the in-mold label has a polyolefin film layer having a surface resistivity of 10 ¹³ Ω / cm ² or more and a barrier synthetic resin film layer as constituent layers. The in-mold temporary adhesion method for an in-mold label according to claim 1, wherein the method is provided.

A fourth invention of the present invention is a laminated film in which the in-mold label has a polyolefin film layer having a surface specific resistance value of 10 ¹³ Ω / cm ² or more and a heat and pressure resistant synthetic resin film layer as constituent layers. The in-mold temporary bonding method for an in-mold label according to claim 1.

In the in-mold temporary bonding method for an in-mold label of the present invention, the surface specific resistance value is 10 ¹³ Ω / cm ^2.
The above in-mold label is temporarily bonded to the cavity surface of the mold for injection molding by the electrostatic force of the in-mold label, and a special mold structure for temporarily bonding to the mold is used. do not need. For this reason, the mold production period is short and the mold production cost is low. Moreover, since the transfer of the label to the mold cavity surface is quicker than the conventional vacuum system, the molding cycle can be increased.

  In addition, according to the in-mold temporary bonding method for an in-mold label of the present invention, it is possible to temporarily bond the in-mold label to a predetermined position on the male or female cavity surface without any restrictions. The novelty can be given to the design property by an in-mold label.

  Moreover, the in-mold label concerning this invention can provide barrier property, heat-resistant pressure resistance, microwave oven suitability etc. easily with the structure of a laminated | multilayer film.

The in-mold temporary bonding method for an in-mold label of the present invention is an injection mold that is opened without requiring a special mold structure such as a vacuum hole for temporarily bonding the in-mold label to the mold. The surface specific resistance value is 10 ¹³ Ω / cm ^{2 on} the cavity surface at a predetermined position of the male or female mold.
The above in-mold label is temporarily bonded by the electrostatic force of the in-mold label itself. The supply movement of the in-mold label into the mold is generally performed mechanically continuously with a label inserter or a robot, but may be manually performed manually. Moreover, the material of the injection mold used is basically iron or steel based on iron. However, even if other materials such as beryllium copper, aluminum, and synthetic resin are partially used, There is no problem if the label can be held.

The in-mold label may be a laminated film having a polyolefin film layer having a surface resistivity of 10 ¹³ Ω / cm ² or more and a barrier synthetic resin film layer as constituent layers. This in-mold label can be used as an in-mold label with high barrier properties, for example, with an oxygen permeability of a level of 0.00X to 0.00Y cc / pg · day · 0.2 atm.

Further, the in-mold label may be a laminated film having a polyolefin film layer having a surface resistivity of 10 ¹³ Ω / cm ² or more and a heat and pressure resistant synthetic resin film layer as constituent layers. This in-mold label can be used as an in-mold label for retort or microwave oven specifications.

First, using “e-sheet” (charged polyethylene sheet) made by Tosmac Co., Ltd. with a surface resistivity of 10 ¹⁴ to 10 ¹⁵ Ω / cm ² , a pattern is printed on the surface, punched out, and circular shaped. An in-mold label was prepared. Next, the mold on the injection molding machine for molding the cup-shaped container (300) shown in FIGS. 3 (a) and 3 (b) is opened and, as shown in FIG. 1 (a), the male mold of the injection mold. The above-mentioned in-mold label (100) was supplied and moved to the cavity surface (210) forming the bottom inner surface of (200) with an inserter, and temporarily adhered by the electrostatic force of the label itself. Then, the mold is clamped, and a high-density polyethylene melted at a molding temperature of 230 ° C. is injected into the cavity (space between the female mold and the male mold) from the gate (pouring gate where the molten resin is injected). The cup-shaped plastic container with the in-mold label of Example 1 was manufactured by simultaneously fusing the back surface of the in-mold label temporarily bonded to the male mold to the inner surface of the bottom of the cup-shaped container. The injection mold was a normal steel mold having no special mold structure such as a vacuum hole for temporary bonding.

  The cup-shaped plastic container with an in-mold label in Example 1 described above has the in-mold label accurately and firmly heat-sealed at a predetermined position on the inner surface of the bottom, and the cup-shaped container is molded in an injection mold. The in-mold label did not shift due to the flow of the molten resin.

  Using the in-mold label and the injection mold of Example 1, as shown in FIG. 1B, the cavity surface (220) that forms the inner peripheral surface of the peripheral wall portion of the male mold (200) is placed at a predetermined position. The in-mold label (100) is supplied and moved by an inserter and temporarily adhered by the electrostatic force of the label itself, and the cup-shaped container (300) shown in FIGS. A cup-shaped plastic container with an in-mold label of Example 2 was produced by molding and heat-sealing the back surface of the in-mold label to the inner peripheral surface of the peripheral wall portion of the cup-shaped container. Similar to Example 1, the in-mold label was not misaligned due to the flow of the molten resin. Conventionally, it has been difficult to temporarily bond an in-mold label to a cavity surface that forms the inner peripheral surface of the male peripheral wall, because of the mold structure, and thus novel design of the product has been observed.

(A) is an in-mold label bonding method for in-mold labels of the present invention. It is explanatory drawing which shows the state when adhering temporarily, (b) is the cavity surface which forms a male peripheral wall part internal peripheral surface, when bonding an in-mold label to the peripheral wall internal peripheral surface of a cup-shaped container It is explanatory drawing which shows a state when temporarily bonding an in-mold label to. It is explanatory drawing of an example which shows the state when an in-mold label is temporarily adhere | attached on the cavity surface which forms the bottom part inner surface of a male type | mold in the conventional in-mold adhesion method of the vacuum type in-mold label. (A) is a front view of an example of a cup-shaped container, and (b) is a bottom view thereof.

Explanation of symbols

100 ... In-mold label 200 ... Male mold 210 ... Cavity surface 211 forming the inner surface of the bottom portion ... Vacuum hole 220 ... Cavity surface 300 forming the inner peripheral surface of the peripheral wall portion ... Copp-shaped container 310 ... Bottom portion 320 …… Surrounding wall 330 …… Gate position

Claims (4)

An in-mold label having a surface resistivity of 10 ¹³ Ω / cm ² or more is applied to the cavity surface at a predetermined position of the male mold or female mold of the mold for injection molding that is opened by the electrostatic force of the in-mold label. An in-mold temporary bonding method for an in-mold label, characterized by temporary bonding. 2. The in-mold temporary bonding method for an in-mold label according to claim 1, wherein the in-mold label is a polyolefin film having a surface resistivity of 10 ¹³ Ω / cm ² or more. The in-mold label according to claim 1, wherein the in-mold label is a laminated film having a polyolefin film layer having a surface specific resistance value of 10 ¹³ Ω / cm ² or more and a barrier synthetic resin film layer as constituent layers. Temporary bonding method for mold label in mold. 2. The in-mold label according to claim 1, wherein the in-mold label is a laminated film having a polyolefin film layer having a surface resistivity of 10 ¹³ Ω / cm ² or more and a heat and pressure resistant synthetic resin film layer as constituent layers. Temporary bonding method for mold label in mold.