Sheet manufacturing method and processing device
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Solution Overview
Problem
Conventional sheet manufacturing methods are limited in imparting stretchability beyond a certain range due to restricted tension application, making it difficult to achieve greater stretchability in base material sheets.
Innovation Solution
A sheet manufacturing method involving a conveying step where the base material sheet is conveyed along the outer peripheral face of one processing roll with tension less than 10% of its breaking load, utilizing friction to decrease tension and restrain shrinkage, allowing for greater stretchability. The method includes heating the processing roll and adjustable roll positioning to optimize engagement and processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tension applying means are used to impart stretchability to the base material sheet, then stretchability is improved, but the extent of stretchability is limited to a certain range and greater stretchability cannot be achieved
Solution Approach 1:
The patent changes the tension parameter from conventional levels (10-90% of breaking load) to a significantly reduced level (less than 10% of breaking load) during the conveying step. This parameter change enables the base material sheet to be stretched beyond the conventional range by allowing greater deformation without exceeding material failure limits, thereby achieving greater stretchability while maintaining material integrity.
2Strength
If the base material sheet is conveyed along the outer peripheral face of the processing roll with low tension, then greater stretchability is achieved, but sheet breakage or damage may occur
Solution Approach 1:
The patent applies preliminary heating to the base material sheet before it enters the processing rolls. This preliminary action increases the material's ductility and reduces its breaking load, allowing it to withstand the low-tension conveying and stretching process without breakage. The heating prepares the material in advance to accommodate the extended stretchability range while maintaining sheet integrity.
3Stability of the object's composition
If conventional tension ranges are used for processing, then processing stability is maintained, but shrinkage in the width direction cannot be effectively restrained
Solution Approach 1:
The patent applies preliminary heating to the base material sheet before processing, which creates an opposing effect to the natural shrinkage tendency. The heating increases material ductility and reduces internal stresses that would otherwise cause width shrinkage during stretching. This preliminary anti-action counteracts the shrinkage force, allowing the sheet to maintain dimensional stability in the width direction while achieving greater stretchability in the conveyance direction.
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
This approach enables the imparting of greater stretchability to base material sheets while preventing breakage or damage, even at high conveyance speeds, by controlling tension and shrinkage, thereby enhancing production efficiency.
Implementation Method 1
the base material sheet is conveyed in a manner that the base material sheet is in contact with and along the outer peripheral face of one processing roll of the processing rolls immediately prior to passing between the processing rolls
Implementation Method 2
a heating step of heating the one processing roll so that the temperature of the outer peripheral face of the one processing roll is not less than 10° C. and not more than 60° C.
Data Source
AI summary
A sheet manufacturing method includes a conveying step of conveying a base material sheet; and a processing step of rotating a pair of processing rolls to sandwich a conveyance path on which the base material sheet is conveyed, wherein irregular portions along respective outer peripheral faces of the processing rolls engage with each other with a clearance to stretch the base material sheet when the base material sheet passes between the processing rolls. In the conveying step, the base material sheet is conveyed such that the base material sheet contacts along the outer peripheral face of one of the processing rolls immediately prior to passing between the processing rolls; and the tension in the conveyance direction applied to the base material sheet immediately prior to reaching the outer peripheral face of the one of the processing rolls is less than 10% of a breaking load of the base material sheet.