JPH0655727U - In-mold label for PET bottle - Google Patents

Abstract

(57) [Summary] [Purpose] When an empty PET bottle after use is applied to a recycling system, the in-mold label of the PET bottle peels off during the pretreatment process. [Constitution] On the back of the in-mold label for PET bottles,
A heat-sensitive adhesive layer is partially formed on a portion corresponding to 10 to 25% of the entire area of the label.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an in-mold label for a PET bottle used for a PET bottle in which an empty bottle after use is subjected to a recycling system.

[0002]

[Prior art]

 In recent years, PET bottles have been used in a wide range of fields such as fruit drinks, foods such as oolong tea, and non-food products such as kitchen detergents, shampoos and conditioners, and the amount of resin used is more than 126,000 tons per year in all countries. Has also reached. In addition, in this PET bottle, the use of in-mold labels, in which a label having a heat-sensitive adhesive layer formed on the entire back surface in advance is inserted and placed in a mold at the time of molding, and a label is applied simultaneously with molding of the bottle, is rapidly increasing. . On the other hand, in recent social conditions, awareness of environmental conservation issues has increased, and a plastic product recycling campaign and container recycling campaign have become popular. At the PET bottle council made by PET bottle manufacturers, Since 1993, we have begun to operate a reprocessing facility.

[0003]

[Problems to be solved by the device]

 Against the background of such social conditions, labels are peeled off by pretreatment (80% to 90 ° C 3% alkaline hot water shower) of the used PET PET recycling system for recycling PET bottles. PET bottles have become sought after. The present invention provides an in-mold label for a PET bottle that is difficult to peel off when washing the container when filling the contents or when using the container, and can be easily peeled off by the pretreatment of the recycling processing system.

[0004]

[Means for Solving the Problems]

 As shown in FIG. 1, the present invention is a PET in which a heat-sensitive adhesive layer (12) is partially formed on the back surface of a label substrate (11) at a portion corresponding to 10 to 25% of the entire label area. It is an in-mold label (10) for bottles.

As the label base material used in the present invention described above, synthetic paper and various kinds of paper are used, and the label is mounted in the hollow molding die at the time of stretch hollow molding or hollow molding of a PET bottle. It

Further, the heat-sensitive adhesive layer is partially printed by a gravure printing method, a silk screen printing method or the like using a heat-sensitive adhesive such as an acrylic type, a cellulose derivative type, a vinyl resin type or a modified wax type. The total printing area is 10 to 25% of the total area of the label, preferably 17 to 22%. Further, the formed heat-sensitive adhesive layer may have any shape such as a strip shape, a lattice stripe shape, or a dot shape.

[0007]

[Action]

 The in-mold label for a PET bottle of the present invention attached to a PET bottle has a heat-sensitive adhesive layer formed on the back surface of 10 to 25% of the total area of the label. The adhesive strength is lower than that when the container is formed so as not to peel off when the container is washed when filling the contents or when the container is used. Moreover, since the adhesive is a heat-sensitive adhesive, it is softened by heat and its adhesive strength is reduced. Further, since the adhesive layer is partially formed, the pretreatment liquid of the reprocessing system easily penetrates into the adhesive layer, and a difference in shrinkage rate between the label and the bottle due to temperature occurs. From the above, the PET bottle with the in-mold label for the PET bottle of the present invention, when treated by the recycling system after use, has a pretreatment process compared with the conventional PET bottle with the label. Therefore, the label is easily peeled off from the PET bottle.

[0008]

【Example】

<Example 1> First, an acrylic heat-sensitive adhesive was used on the periphery of the back surface of the label substrate (11) made of synthetic paper by a gravure printing method, as shown in FIG. A band-shaped heat-sensitive adhesive layer (12) and a dot-shaped heat-sensitive adhesive layer (14) were formed on the inside of the book-shaped heat-sensitive adhesive layer (12) to prepare a PET in-mold label (10) of this example. Further, for comparison, the same label base material and adhesive were used to form a heat-sensitive adhesive layer on the entire back surface of the label base material to produce a conventional PET in-mold label. The coating amount of the adhesive was 2.0 g / m ² in terms of all solids (uniform coating on the entire surface). In addition, the total area of the heat-sensitive adhesive layer of the PET in-mold label of this example was about 13% of the entire label surface. The reason why the strip-shaped heat-sensitive adhesive layer on the outer peripheral portion is separated into four layers to provide a gap is that the pretreatment liquid easily enters between the back surface of the label and the bottle.

Next, using a normal stretch blow molding machine, the prepared in-mold label for PET of the present example was placed in a mold for hollow molding, and was subjected to hollow molding with polyethylene terephthalate to perform front and back sides. A PET bottle with an in-mold label attached was prepared. Similarly, using a conventional PET in-mold label, PET bottles having in-mold labels attached to the front and back were manufactured.

Next, the two types of PET bottles produced were examined through a recycling system. The PET bottle with the in-mold label of the present invention showed a pretreatment step (80% to 90 ° C, 3% alkaline hot water). In the shower), the labels on the front and back were completely peeled off, and a high-grade transparent recycled product was obtained. On the other hand, in the PET bottle to which the conventional in-mold label was attached, the front and back labels were not completely peeled off in the pretreatment process.

Example 2 First, a modified wax-based heat-sensitive adhesive was used on the back surface of the label base material (21) made of synthetic paper by a gravure printing method, as shown in FIG. The heat-sensitive adhesive layer (22) was formed to prepare the PET in-mold label (20) of this example. The amount of adhesive applied was 2.0 g / m ² in terms of all solids (uniformly applied over the entire surface). The total area of the heat-sensitive adhesive layer was about 22% of the entire surface of the label. If the pitch of the checkered pattern is large, wrinkles are likely to occur on the label, so the pitch should be small.

Next, using a normal stretch blow molding machine, the prepared in-mold label for PET of the present example was mounted in a mold for hollow molding, and was subjected to hollow molding with polyethylene terephthalate to perform front and back sides. A PET bottle with an in-mold label attached was prepared.

Next, the produced PET bottle of this example was subjected to a reprocessing system in the same manner as in Example 1, and the labels on the front and back sides were completely peeled off in the pretreatment step, and a highly transparent reclaimed product was obtained. Was obtained.

Example 3 First, as shown in FIG. 3, dots were formed on the back surface of the label substrate (31) made of synthetic paper by an gravure printing method using an ethylene / vinyl acetate-based heat-sensitive adhesive. A heat-sensitive adhesive layer (32) having a pattern was formed to prepare an in-mold label for PET (30) of this example. The amount of adhesive applied was 2.0 g / m ² in terms of total solid. The total area of the heat-sensitive adhesive layer was about 14% of the entire label surface.

Next, using a normal blow molding machine, the prepared in-mold label for PET of this example was mounted in a mold, and blow molded with a polyethylene terephthalate copolymer, and in-mold labels were printed on the front and back sides. A pasted PET bottle was produced.

Next, the produced PET bottle of this example was subjected to a reprocessing system in the same manner as in Example 1, but the labels on the front and back were completely peeled off in the pretreatment step, and a high-quality transparent reclaimed product was obtained. Was obtained.

[0017]

[Effect of device]

 The PET bottle produced by using the in-mold label for PET bottle of the present invention is a PET bottle that is difficult to peel off when washing the container at the time of filling the contents or when using the container, and as shown in the examples, the PET bottle When applied to the recycle processing system, the label is completely peeled off in the pretreatment step (3% alkaline hot water shower at 80 to 90 ° C) of the recycle processing system, and a highly transparent reclaimed product is obtained.

[Brief description of drawings]

FIG. 1 is a plan view of the back surface of a PET in-mold label of the present invention in which a heat-sensitive adhesive layer is formed in Example 1.

FIG. 2 is a plan view of the back surface of the PET in-mold label of the present invention in which a heat-sensitive adhesive layer is formed in Example 2.

FIG. 3 is a plan view of the back surface of the PET in-mold label of the present invention in which a heat-sensitive adhesive layer is formed in Example 3.

[Explanation of symbols]

 10, 20, 30 ... PET in-mold label 11, 21, 31 ... Label substrate 12, 14, 22, 32 ... Heat-sensitive adhesive layer

Claims (1)

[Scope of utility model registration request] 1. The total area of the label is 1 on the back surface of the label substrate.
An in-mold label for a PET bottle, wherein a heat-sensitive adhesive layer is partially formed on a portion corresponding to 0 to 25%.