Paper Drinking Straw Dip-Coating for Complete Water-Resistant Coverage
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Solution Overview
Problem
Conventional paper straws made from pre-coated paper sheets have exposed edges and ends that are not coated, leading to water absorption and reduced durability due to incomplete water-resistant coating coverage.
Innovation Solution
An apparatus and method for coating pre-formed paper drinking straws with a water-resistant coating in a dipping tank, ensuring all surfaces are coated, including edges and ends, using a conveyor system and drying process to remove excess coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-coated paper sheets are used to manufacture straws, then water-resistant coating is applied to the paper surface, but edges and ends remain uncoated and exposed to water absorption
Solution Approach 1:
Instead of coating the paper sheet before forming straws (conventional approach), the invention forms straws first from uncoated paper, then applies the water-resistant coating to the finished straw. This inversion ensures all surfaces including edges and ends are coated, eliminating the coverage problem while simplifying the process.
Solution Approach 2:
The straw is formed into its final tubular shape with overlapping edges before the coating step. This preliminary formation action ensures that when coating is applied subsequently, all surfaces including the previously exposed edges are already in their final positions and can be fully coated.
2Weight of moving object
If paper straws are made from uncoated paper, then the paper is lighter and more flexible, but the straws absorb water and lose structural integrity
Solution Approach 1:
The invention changes the parameter of coating application timing from 'before straw formation' to 'after straw formation'. This allows the use of uncoated (lighter, more flexible) paper during forming, then applies water-resistant coating to the finished straw, achieving both light weight and structural integrity.
3Manufacturing precision
If conventional pre-coated paper manufacturing is used, then coating is applied to the paper sheet, but the overlapping spiral edge and cut ends remain uncoated
Solution Approach 1:
The invention inverts the sequence: instead of coating paper then forming straws (which leaves edges uncoated), it forms straws then coats them. This simple inversion achieves complete coating coverage of all surfaces including edges and ends, eliminating the need for complex selective coating apparatus.
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 provides complete water-resistant coverage on all surfaces of the straw, enhancing durability and reducing water absorption, while also being more cost-effective due to the use of uncoated, lighter, and more flexible paper.
Implementation Method 1
a liquid bath for coating an uncoated drinking straw when submerged in the bath
Implementation Method 2
a dryer or other means for removing excess coating from the surface of the straws after being submerged in the bath
Data Source
AI summary
A method for coating a paper drinking straw, an apparatus for coating a paper drinking straw, and a coated drinking straw assembly are disclosed. The apparatus includes a dipping tank containing a liquid bath for coating a straw when submerged in the liquid and a straw engagement means for submerging the straw in the bath. The method includes receiving an uncoated paper drinking straw and submerging the straw in a bath containing a water-resistant and/or a water-soluble coating. The drinking straw assembly includes an elongate tubular body and a coating that has been applied to all surfaces of the straw by submerging the body in a bath containing the coating.