Polyethylene Foam Sheet Anti-static Layer Design
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Solution Overview
Problem
There is a need for a polyethylene-based resin laminated foam sheet with a low thickness that prevents the occurrence of small holes or through holes while maintaining excellent anti-static performance over medium- to long-term periods, especially for use as an interleaf for thin glass plates in image display devices.
Innovation Solution
A method for producing a polyethylene-based resin laminated foam sheet with a thickness of 0.05 to 0.5 mm, involving coextrusion and foaming of a laminate combining low density polyethylene and a physical foaming agent for the foam layer, and low density polyethylene with a polymeric anti-static agent for the anti-static layer, where the anti-static agent has a specific melting point difference and high melt flow rate, ensuring the anti-static layer is adhered on at least one surface of the foam layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a foam sheet with low thickness is produced, then the loading efficiency is improved and the interleaf thickness becomes appropriate for thin glass plates, but small holes or through holes easily occur in the foam sheet
Solution Approach 1:
The patent applies parameter changes by carefully controlling the melting point and melt flow rate of the anti-static agent. The anti-static agent is selected to have a melting point within 10°C of the base resin and a melt flow rate of 10 g/10 minutes or more, which prevents crystallization during extrusion and maintains foam sheet integrity at low thickness while avoiding hole formation
Solution Approach 2:
The patent utilizes phase transitions by controlling the melting and crystallization behavior of the anti-static agent. By selecting an anti-static agent with appropriate melting point and high melt flow rate, the material remains in a plastic state during extrusion and foaming, preventing crystallization-induced hole formation in thin foam sheets
2Productivity
If continuous production is maintained over medium- to long-term periods, then productivity is improved, but anti-static performance deteriorates due to agent crystallization
Solution Approach 1:
The patent maintains anti-static performance during continuous production by controlling the melt flow rate of the anti-static agent to be 10 g/10 minutes or more. This high melt flow rate prevents crystallization even during long-term continuous operation, ensuring stable anti-static performance while maintaining high productivity
Solution Approach 2:
The patent ensures continuous anti-static functionality by selecting an anti-static agent that remains in a plastic state during continuous extrusion and foaming operations. The high melt flow rate and appropriate melting point ensure the agent does not crystallize during continuous production, maintaining uninterrupted anti-static performance
3Reliability
If a polymeric anti-static agent with low melting point is used, then anti-static performance is improved, but the agent crystallizes during storage and production causing hole formation
Solution Approach 1:
The patent resolves this contradiction by optimizing two key parameters simultaneously: the melting point is controlled to be within 10°C of the base resin to ensure compatibility and prevent phase separation, while the melt flow rate is maintained at 10 g/10 minutes or more to prevent crystallization during processing, thereby achieving both good anti-static performance and high manufacturing quality
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 resulting foam sheet exhibits high quality with suppressed hole occurrence and excellent anti-static performance, even during continuous production over several days, enhancing industrial production efficiency and preventing damage to thin glass plates during packaging and conveying.
Implementation Method 1
a step of performing coextrusion and foaming of a laminate which is obtained by combining and laminating, in a die, a melt resin composition for forming a foam layer obtained by kneading a low density polyethylene A and a physical foaming agent
Implementation Method 2
the anti-static agent is a polymeric anti-static agent C which has a melting point to allow a melting point difference in the range of from -10°C to +10°C compared to that of the low density polyethylene B and has a melt flow rate of 10 g/10 minutes or more
Data Source
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AI summary
A method for producing a polyethylene-based resin laminated foam sheet according to the present invention is a method for producing a polyethylene-based resin laminated foam sheet 1 with thickness of 0.05 to 0.5 mm in which an anti-static layer is adhered by lamination on at least one surface of the foam layer, including: a step of performing coextrusion and foaming of a laminate which is obtained by combining and laminating, in a die 10, a melt resin composition 6 for forming a foam layer obtained by kneading a low density polyethylene A and a physical foaming agent and a melt resin composition 9 for forming an anti-static layer obtained by kneading a low density polyethylene B and an anti-static agent, wherein the anti-static agent is a polymeric anti-static agent C which has a melting point to allow a melting point difference in the range of from -10°C to +10°C compared to that of the low density polyethylene B and has a melt flow rate of 10 g/10 minutes or more.