Intermittent Adhesive Coating for Stretchable Composite Pleats
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Solution Overview
Problem
Existing elastic stretchable components in absorbent products, such as disposable diapers, suffer from poor flexibility and an unpleasant touch due to linear joining portions, which cause the sheet to bulge out and form uneven pleats, making the product neither soft nor pleasant to the touch.
Innovation Solution
An apparatus with a coating head having slit grooves applies adhesive over the entire peripheral surface of rubber threads, and a rotating cam body with protrusions moves the threads between coating and non-coating positions, allowing for point contacts between the rubber threads and nonwoven fabric, forming continuous pleats with flat surfaces in between, creating a more flexible and soft-touch product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to form linear application areas to join elastic members to sheet material, then the joining strength is improved, but the flexibility and tactile comfort deteriorate
Solution Approach 1:
The patent divides the adhesive application from continuous linear areas into discrete point contacts. The coating head applies adhesive only at specific points along the elastic member rather than along continuous lines, segmenting the bonding areas to maintain flexibility while ensuring adequate joining strength at critical contact points.
Solution Approach 2:
The patent applies adhesive with different properties at different locations. By using point contact application, the adhesive is concentrated at specific locations where bonding is needed, while leaving other areas adhesive-free to maintain the natural flexibility and softness of the sheet material. This creates local variations in bonding strength and material properties.
2Stability of the object's composition
If linear joining portions are formed to fix sheets together, then the structural stability is improved, but the pleat uniformity and softness deteriorate
Solution Approach 1:
The patent segments the joining portions from continuous linear structures to discrete point contacts. This segmentation allows the sheet material to form uniform pleats between the joining points while maintaining adequate structural stability at the bonded locations, eliminating the bulging effect caused by linear adhesive areas.
Solution Approach 2:
The coating head moves periodically along the elastic member, applying adhesive at regular intervals rather than continuously. This periodic application creates a series of uniformly spaced point contacts that allow consistent pleat formation between bonding points while maintaining overall structural integrity.
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 enhances flexibility and tactile comfort by forming point contacts between the rubber threads and nonwoven fabric, reducing adhesive usage and enabling the creation of soft, continuous pleats suitable for absorbent products like disposable diapers.
Implementation Method 1
a coating head 10 that has slit grooves 5 in which coating agent reservoirs Q are formed and that applies an adhesive HM over the entire peripheral surface of stretchable members (rubber threads) R passing through the coating agent reservoirs Q
Implementation Method 2
a rubber thread vertical drive device 1 that moves the rubber threads R passing through the coating agent reservoirs of the slit grooves up and down between a coating position at which the rubber threads pass through the coating agent reservoirs and a non-coating position at which the rubber threads pass away from the coating agent reservoirs Q
Data Source
AI summary
A stretchable composite sheet, wherein pleat-free regions where no pleats are formed are formed between a plurality of pleat formation regions, the sheet being made by a method, wherein non-continuous coating sections are set so as to correspond to form the plurality of pleat formation regions, and non-coating sections are set so as to correspond to form the pleat-free regions, and an intermittent coating is performed on stretchable elastic members (rubber threads). An apparatus for non-continuously and intermittently applying a hot-melt adhesive comprises an intermittent coating unit, which includes a hot-melt supply control device having a valve mechanism and a coating head having slit grooves in which coating areas are formed, and a non-continuous coating unit, which vertically vibrates rubber threads, passing through the coating areas, between a coating position and a non-coating position.