Heat Sealable Printing Sheet Ink Receiving Layer Tg Optimization
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Solution Overview
Problem
Existing heat sealable printing sheets face challenges in achieving optimal ink absorbability, adhesiveness, and unwrapping characteristics due to the thickness of the ink receiving layer, which can lead to peeling and cracking issues, especially when folded at acute angles or during unwrapping.
Innovation Solution
A heat sealable printing sheet comprising a sheet-shaped base member with an ink receiving layer containing inorganic fine particles, a water soluble resin, and a water dispersible resin, where the glass transition temperature of the water dispersible resin is set between -35°C and 35°C, and the resins' SP values are close to those of the heat sealable resin material, enhancing adhesiveness and preventing stickiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an ink receiving layer is provided on the wrapping film to enable inkjet printing, then printing characteristics are improved, but the layer may peel off or remain as a burr during unwrapping due to additional thickness
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature (Tg) of the water dispersible resin within -50°C to 0°C range and adjusting the SP value to be within 2.0 of the heat sealable resin material. These parameter optimizations enable the ink receiving layer to achieve both good ink absorbability and sufficient adhesiveness to prevent peeling during unwrapping, resolving the contradiction between printing characteristics and unwrapping reliability.
Solution Approach 2:
The patent uses composite materials by formulating the ink receiving layer with a specific composition: inorganic fine particles (for ink absorbability), water soluble resin (for film formation), and water dispersible resin (for adhesiveness). This composite structure allows the layer to simultaneously achieve printing characteristics and prevent peeling during unwrapping, resolving the technical contradiction.
2Quantity of substance
If the ink receiving layer thickness is increased to improve ink absorbability, then printing quality is improved, but the film becomes harder and may crack or peel when folded at acute angles
Solution Approach 1:
The patent applies parameter changes by optimizing the glass transition temperature (Tg) of the water dispersible resin to be within -50°C to 0°C. This parameter control allows the ink receiving layer to maintain adequate thickness for ink absorbability while ensuring the layer remains flexible enough to prevent cracking when folded at acute angles, thus resolving the contradiction between ink absorbability and foldability.
Solution Approach 2:
The patent applies local quality by creating an ink receiving layer with specific compositional characteristics (inorganic fine particles, water soluble resin, and water dispersible resin with controlled Tg and SP value) that provides both sufficient ink absorbability and flexibility. This localized optimization of layer properties resolves the contradiction between quantity of ink absorption and flexibility for folding.
3Reliability
If a heat sealable layer is provided on the back surface to ensure heat sealability, then sealing performance is improved, but adhesiveness between the ink receiving layer and heat sealable layer needs careful control
Solution Approach 1:
The patent applies parameter changes by controlling the SP value of the water dispersible resin to be within 2.0 of the heat sealable resin material. This parameter optimization ensures proper adhesiveness between the ink receiving layer and heat sealable layer, allowing the heat sealable layer to provide sealing performance while maintaining appropriate bond strength without excessive complexity in adhesiveness control.
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 solution provides a heat sealable printing sheet with improved ink absorbability, adhesiveness between layers, and favorable unwrapping characteristics, preventing peeling and cracking, while maintaining transparency and ink density.
Implementation Method 1
the water dispersible resin has a glass transition temperature Tg satisfying the following expression (1): -35°C.≦Tg≦35°C
Implementation Method 2
an ink receiving layer disposed on a first surface of the base member and having a heat sealability
Implementation Method 3
the ink receiving layer and the heat sealable layer should be controlled to be kept from adhering to a packaged object during thermal pressure bonding
Data Source
AI summary
A heat sealable printing sheet includes a sheet-shaped base member, and an ink receiving layer disposed on a first surface of the base member and having a heat sealability. The heat sealable printing sheet further includes a heat sealable layer disposed on a second surface of the base member and made of a heat sealable resin material. The ink receiving layer contains inorganic fine particles, a water soluble resin, and a water dispersible resin. The water dispersible resin has a glass transition temperature (Tg) satisfying −35° C.≦Tg≦35° C.