Multilayer Release Sheet Structure to Prevent Curling
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Solution Overview
Problem
Mold release sheets with thick crystalline polyolefin resin layers curl during heating and drying, reducing their workability and reusability in producing resin films like synthetic leathers.
Innovation Solution
A multilayer structure is implemented in the mold release sheet, comprising an intermediate layer of amorphous polyolefin resin and a surface layer of crystalline polyolefin resin, with specific thickness ranges and resin compositions to prevent curling and enhance reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thick release layer comprising a crystalline polyolefin resin is formed on one surface of a substrate, then the release layer can transfer deep patterns on the resin film surface, but the sheet curls during heating and drying, deteriorating workability in repeated use
Solution Approach 1:
The release layer is divided into two distinct layers: a first release layer (30-200 μm) comprising a crystalline polyolefin resin for pattern transfer, and a second release layer (10-100 μm) comprising an amorphous polyolefin resin to prevent curling. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between deep pattern transfer and curl prevention.
Solution Approach 2:
The invention uses a composite structure combining two different polyolefin resins with distinct properties: a crystalline polyolefin (for deep pattern transfer) and an amorphous polyolefin (for curl prevention). The composite multilayer structure leverages the complementary properties of both materials to achieve both deep pattern transfer capability and curl-free operation during repeated use.
2Manufacturing precision
If the release layer thickness is increased to transfer deep patterns, then pattern transfer capability improves, but curling during heating and drying increases
Solution Approach 1:
The release layer is segmented into a thick first release layer (30-200 μm) for pattern transfer and a thinner second release layer (10-100 μm) for curl control. This segmentation allows the first layer to provide sufficient thickness for deep pattern transfer while the second layer acts as a constraint to prevent excessive curling during thermal processing.
Solution Approach 2:
The invention changes the material parameter from purely crystalline polyolefin to a combination of crystalline and amorphous polyolefins. The amorphous polyolefin in the second layer has different thermal and mechanical properties that counterbalance the curling tendency of the thick crystalline polyolefin layer, thereby controlling the overall shape stability during heating and drying.
3Device complexity
If a single-layer thick release layer is used, then the structure is simple and cost-effective, but curling occurs during heating and drying
Solution Approach 1:
Rather than using a single thick layer, the release layer is segmented into two layers with different functions. The first layer handles pattern transfer while the second layer manages dimensional stability. This segmentation adds some structural complexity but eliminates the need for additional processing steps or support structures, ultimately simplifying the overall system.
Solution Approach 2:
The composite structure of crystalline and amorphous polyolefin layers provides inherent curl resistance through material property complementarity, eliminating the need for external support structures or complex processing controls. This maintains relative structural simplicity while significantly improving workability after heating and drying.
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 multilayer structure effectively relieves curling and maintains high workability, allowing for repeated use without curling, even with thick release layers, and supports the production of resin films with deep patterns.
Implementation Method 1
When the mold release sheet described above in which a release layer having a large thickness is formed from a crystalline polyolefin-based resin is dried by heating, it is curled
Implementation Method 2
the above release layer is allowed to assume a multilayer structure comprising an intermediate layer composed of a specific material I for forming a coating film and a surface layer composed of a material II for forming a coating film containing a crystalline polyolefin resin
Data Source
AI summary
Provided by the present invention is a mold release sheet used in producing resin films such as synthetic leathers and the like in which a curling phenomenon is relieved even when the sheet is formed by a thick release layer and which has a good workability in repeated use. In the mold release sheet of the present invention in which a release layer is formed on one surface of a substrate, the above release layer assumes a multilayer structure which comprises an intermediate layer formed on a substrate side by using a material I for forming coating film containing an amorphous polyolefin resin (A) alone or a resin mixture (B) composed of an amorphous polyolefin resin and a crystalline polyolefin resin and which comprises a surface layer formed on the intermediate layer by using a material II for forming a coating film containing a crystalline polyolefin resin.