In-Mold Label Layer Structure to Resist Silicone Transfer
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Solution Overview
Problem
The adhesiveness of in-mold labels decreases due to the transfer of silicone from the protective layer to the heat-sealable resin layer during storage and handling, leading to reduced bonding with the container.
Innovation Solution
Incorporating an adhesive strength decrease-inhibiting layer containing a (meth)acrylic acid based copolymer with a polar group on the outermost surface of the heat-sealable resin layer to prevent silicone transfer and maintain adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a protective layer containing silicone is provided on the printed layer to prevent scratches and dirt, then the protective performance is improved, but the adhesiveness of the heat-sealable resin layer decreases due to silicone transfer
Solution Approach 1:
An adhesive strength decrease-inhibiting layer is introduced as an intermediary between the heat-sealable resin layer and the protective layer containing silicone. This intermediate layer prevents silicone transfer from the protective layer to the heat-sealable resin layer, thereby maintaining adhesiveness while preserving the protective performance against scratches and dirt.
Solution Approach 2:
The label structure is segmented into distinct functional layers: a heat-sealable resin layer for bonding to the container, an adhesive strength decrease-inhibiting layer to prevent silicone contamination, and a protective layer for scratch and dirt protection. This segmentation allows each layer to perform its specific function without interfering with the others.
2Ease of operation
If silicone is blended into the coating liquid to increase surface slipperiness, then the surface slipperiness is improved, but the adhesiveness of the in-mold label decreases due to silicone transfer to the heat-sealable resin layer
Solution Approach 1:
The adhesive strength decrease-inhibiting layer serves as a protective intermediary that blocks silicone migration from the slipperiness-enhanced protective layer to the heat-sealable resin layer. This allows the beneficial surface slipperiness to be maintained while preventing the harmful adhesive degradation.
Solution Approach 2:
The solution addresses the silicone transfer problem by adding a new dimensional element (the adhesive strength decrease-inhibiting layer) between the protective layer and the heat-sealable resin layer, rather than trying to modify the existing layers. This intermediate dimension effectively blocks the transfer path of silicone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The adhesive strength decrease-inhibiting layer effectively prevents silicone transfer, thereby maintaining the adhesiveness of the in-mold label to the container surface.
Implementation Method 1
an adhesive strength decrease-inhibiting layer containing a (meth)acrylic acid based copolymer having a polar group is provided on an outermost surface on the other surface side of the substrate layer on which the heat-sealable resin layer is provided
Data Source
Figure 1~2
AI summary
A decrease in the adhesiveness of an in-mold label can be suppressed even when a silicone transferred from the protective layer side to the heat-sealable resin layer side. An in-mold label includes a substrate layer, a printed layer provided on one surface of the substrate layer, and a heat-sealable resin layer provided on the other surface of the substrate layer, a protective layer containing a silicone is provided on an outermost surface on one surface side of the substrate layer on which the printed layer is provided, and an adhesive strength decrease-inhibiting layer containing a (meth)acrylic acid based copolymer having a polar group is provided on an outermost surface on the other surface side of the substrate layer on which the heat-sealable resin layer is provided.