Polymeric Layer Blind Openings Thermal Decomposition
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Solution Overview
Problem
There is a need for simple and economical techniques to create composite layers, including films and sheets, with blind holes that penetrate through some but not all layers, which is not effectively addressed by existing methods.
Innovation Solution
The creation of polymeric layers with blind openings that extend into one major surface but not through the other, using a method involving co-extruded netting with different materials and strand arrangements, where the bond regions are perpendicular to the major surfaces, and the openings have varying areas from minimum to maximum, with specific material differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical perforating devices (intermeshing rollers, die punching, needlepunching) are used to create perforations in films, then liquid permeability is achieved, but the process becomes complex and costly
Solution Approach 1:
The patent replaces mechanical perforating devices with a chemical/thermal process. Specifically, it uses a coating composition containing a first polymer and a second polymer that decomposes at a lower temperature to create blind holes through thermal decomposition, eliminating the need for complex mechanical perforation equipment while achieving liquid permeability
Solution Approach 2:
The invention utilizes phase transition through thermal decomposition. The second polymer in the coating composition decomposes at a lower temperature than the first polymer, creating void spaces (blind holes) that provide liquid permeability. This phase transition approach replaces mechanical perforation with a controlled thermal process
2Productivity
If thermal zones or lasers are used to melt perforations into the film, then perforation speed increases, but energy consumption increases and control precision becomes difficult
Solution Approach 1:
The patent changes the parameters of the coating composition to include polymers with different decomposition temperatures. The second polymer is specifically selected to decompose at a lower temperature than the first polymer, allowing controlled formation of blind holes through thermal decomposition. This approach provides better energy efficiency and control compared to high-energy laser or thermal zone methods
3Reliability
If quenching polypropylene into beta phase crystals followed by orientation is performed to create porous films, then porosity is achieved, but the manufacturing process becomes complex
Solution Approach 1:
The invention uses a composite coating composition containing two different polymers with distinct thermal properties. The first polymer forms the continuous phase while the second polymer creates the porous structure through selective decomposition. This composite material approach simplifies the manufacturing process compared to complex quenching and orientation procedures required for beta-phase polypropylene
Data Source
Figure 1~1A
Figure 2
Figure 3~3A
AI summary
Polymeric layers comprising an array of blind openings extending into the first major surface, but not through the second major surfaces. The blind openings each have a series of areas through the openings from the first major surface towards the second major surfaces ranging from minimum to maximum areas, where for at least a majority of the blind openings the minimum area is not at the first major surface. At least a portion of the first major surface comprises a first material and extends up to, but not into the second major surface. At least a portion of the second major surface comprises a second, different material. Methods for making the polymeric layers are also disclosed. Polymeric layers are useful, for example, as components in personal care garments such as diapers and feminine hygiene products. They can also be useful for filtering (including liquid filtering) and acoustic applications.