In-Mold Label Heat-Sealing Composition for Clean Resin Recycling
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Solution Overview
Problem
In-mold labels with strong adhesive strength to resin containers pose challenges during recycling, leading to difficult peeling and potential contamination of recycled materials, and require high-temperature alkali treatment with complex process control.
Innovation Solution
An in-mold label with a tack force of 0.8 N/cm² or less and an area dimension change rate of 1% or less at 80°C, utilizing a heat sealing layer with specific thermoplastic resins and a multilayer structure to facilitate easy peeling during recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive strength of the in-mold label is increased to prevent peeling during storage and conveyance, then the label maintains good adhesion in normal use, but the label becomes difficult to peel during recycling and requires high-temperature alkali treatment
Solution Approach 1:
The invention changes the chemical composition parameters of the heat sealing layer by incorporating specific additives (icaridin, ethyl carboxymethyl cellulose, and polyethylene glycol) in controlled amounts. This modifies the adhesive properties of the label to achieve optimal balance between adhesion strength and peeling ease, resolving the contradiction between maintaining strong adhesion during use and enabling easy peeling during recycling
Solution Approach 2:
The invention creates a composite heat sealing layer by combining thermoplastic resin with specific additives (icaridin, ethyl carboxymethyl cellulose, and polyethylene glycol). This composite structure provides both strong adhesive properties for normal use and controlled peeling characteristics for recycling, simultaneously addressing both requirements
2Ease of manufacture
If high-temperature alkali treatment is applied to peel the label during recycling, then the label can be removed even with strong adhesive strength, but the process control becomes complicated and costs increase
Solution Approach 1:
The heat sealing layer is designed to automatically peel off during recycling through its inherent chemical composition and thermal properties. The specific additives (icaridin, ethyl carboxnymethyl cellulose, and polyethylene glycol) enable the label to self-peel at recycling temperatures without requiring complex alkali treatment processes, thereby simplifying the recycling process control
Solution Approach 2:
The invention uses a heat sealing layer with controlled adhesive properties that is designed to be temporarily attached during use but easily removed during recycling. The specific composition allows the label to serve its purpose during normal use and then be readily discarded or peeled off without requiring expensive or complex removal processes
3Strength
If the label has strong adhesive strength to the resin container, then the label does not peel easily during storage and conveyance, but the label components may dissolve in alkali solution during recycling and contaminate the resin container
Solution Approach 1:
The invention modifies the chemical composition parameters of the heat sealing layer by incorporating specific additives in controlled amounts. This changes the solubility characteristics of the label materials in alkali solutions while maintaining adhesive strength, thereby preventing contamination of the resin container during recycling
Solution Approach 2:
The specific additives (icaridin, ethyl carboxnymethyl cellulose, and polyethylene glycol) act as intermediary substances that modify the interaction between the label and alkali solution. These intermediaries prevent the dissolution of label components in alkali while maintaining the adhesive function during normal use, thus preventing contamination
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 label easily peels from resin containers during recycling, reducing contamination and simplifying the process, while maintaining adhesion in normal use conditions.
Implementation Method 1
a heat sealing layer that adheres to the resin container
Implementation Method 2
the heat sealing layer contains a thermoplastic resin having a melting point of 90 to 110° C.
Implementation Method 3
an absolute value of an area dimension change rate of 1% or less at 80° C.
Data Source
AI summary
There is provided an in-mold label that is easily peeled from a resin container during recycling. The in-mold label has an absolute value of an area dimension change rate of 1% or less at 80° C. and a tack force of 0.8 N/cm2 or less at 80° C. The in-mold label can be adhered to a resin container that is a stretch blow-molded body.