Starch Viscosity Control for Dry Shaped Article Bonding
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Solution Overview
Problem
Existing methods for producing shaped articles using recycled paper struggle to enhance the strength of the final product, particularly in dry shaping processes, due to insufficient gelatinization of starch, which affects the bonding between fibers.
Innovation Solution
A method involving a mixture of fibers and starch with inorganic oxide particles, where the starch has a controlled viscosity of 20 mPa·s to 200 mPa·s at 50°C, is deposited and moistened, then subjected to heat and pressure to improve bonding and strength, utilizing composite particles with inorganic oxide particles on the surface to prevent aggregation and enhance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If starch is used as gluing material in dry shaping, then the bonding between fibers is improved, but the strength of the shaped article is insufficient due to insufficient gelatinization
Solution Approach 1:
The patent changes the physical and chemical parameters of starch by controlling its viscosity within a specific range (20-200 mPa·s at 50°C) and adjusting the water content (5-20 mass%), which enables proper gelatinization and achieves reliable bonding strength in dry shaping
2Productivity
If a small amount of water is used in dry shaping, then the shaping process is efficient, but the starch gelatinization is insufficient
Solution Approach 1:
The patent optimizes the water content parameter to a specific range (5-20 mass%) and controls starch viscosity (20-200 mPa·s at 50°C), enabling sufficient gelatinization while maintaining the efficiency of dry shaping processes
3Strength
If starch with high viscosity is used, then the bonding between fibers is enhanced, but the distribution of starch becomes uneven
Solution Approach 1:
The patent controls the starch viscosity within an optimal range (20-200 mPa·s at 50°C), which balances the bonding capability with adequate flowability for uniform distribution throughout the fiber matrix
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 results in a stronger shaped article with improved bonding between fibers, suitable for dry shaping, by ensuring effective gelatinization and distribution of starch, leading to enhanced mechanical properties and reduced unevenness.
Implementation Method 1
the starch has a viscosity of 20 mPa·s or more and 200 mPa·s or less as a final viscosity at 50° C. of a 25% by mass aqueous suspension of the starch measured using a Rapid Visco Analyzer
Implementation Method 2
a shaping step, in which heat and pressure are applied to the mixture supplied with the water to give a shaped article
Data Source
AI summary
A method for producing a shaped article includes a deposition step, in which a mixture containing fibers and starch is deposited in the air; a moistening step, in which the mixture is supplied with water; and a shaping step, in which heat and pressure are applied to the mixture supplied with water to give a shaped article. The starch has a viscosity of 20 mPa·s or more and 200 mPa·s or less as a final viscosity at 50° C. of a 25% by mass aqueous suspension of the starch measured using a Rapid Visco Analyzer.