Fiber-Starch Molded Body Manufacturing with Controlled Gelatinization
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Solution Overview
Problem
Existing methods for manufacturing molded bodies using dry fiber binding, such as paper products, often result in inferior mechanical strength due to the use of starch as a binding material.
Innovation Solution
A method involving the deposition of a fiber and starch mixture in air, followed by moisturizing and molding under controlled conditions using a rapid visco analyzer (RVA) to achieve a starch value of 2,000 to 10,000, represented by the expression (I): 5,000−30×T1−90×(T2−T1)+2×η1−15×η2, where T1, T2, η1, and η2 represent gelatinization and viscosity parameters, to enhance binding and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If starch is simply mixed with fibers in dry molding, then water usage is reduced, but the molded body has inferior mechanical strength
Solution Approach 1:
The invention changes the physical and chemical parameters of starch by controlling gelatinization temperature (T1, T2) and viscosity (η1, η2) to achieve optimal binding properties. By adjusting these parameters within specific ranges, the starch forms effective bonds between fibers while maintaining dry molding advantages, thus resolving the contradiction between water reduction and strength improvement.
Solution Approach 2:
The invention utilizes the phase transition of starch during gelatinization (from crystalline to amorphous state) to enhance binding between fibers. By controlling the gelatinization process through temperature and viscosity parameters, the starch transitions to a state that provides optimal adhesion, enabling strong molded bodies without excessive water usage.
2Strength
If starch with high binding capability is used, then mechanical strength improves, but gelatinization temperature and viscosity control become more difficult
Solution Approach 1:
The invention establishes specific ranges for gelatinization temperature (T1, T2) and viscosity (η1, η2) parameters that balance binding capability with process controllability. By defining these parameter windows, the invention makes it easier to control the gelatinization process while maintaining high mechanical strength, thus resolving the contradiction between strength improvement and process complexity.
3Strength
If excessive heating and pressurizing is applied to improve binding, then mechanical strength increases, but fiber damage and energy consumption increase
Solution Approach 1:
The invention optimizes heating and pressurizing parameters by controlling gelatinization temperature and viscosity within specific ranges. This allows achieving strong binding between fibers through controlled starch gelatinization rather than excessive external heating and pressurizing, thus reducing energy consumption while maintaining mechanical strength.
Solution Approach 2:
The invention replaces mechanical heating and pressurizing with chemical-physical gelatinization of starch as the primary binding mechanism. By utilizing the gelatinization properties of starch (controlled by T1, T2, η1, η2 parameters), the binding force is generated internally through starch transformation rather than external mechanical forces, reducing energy consumption and fiber damage.
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 method produces molded bodies with improved mechanical strength by balancing water absorption, gelatinization, and viscosity characteristics, reducing fiber damage and energy consumption while maintaining surface smoothness.
Implementation Method 1
T1 represents a gelatinization start temperature (° C.), T2 represents a gelatinization peak temperature (° C.)
Implementation Method 2
a moisturizing step of applying water to the mixture
Implementation Method 3
a molding step of forming a molded body by heating and pressurizing the mixture
Implementation Method 4
a molding step of forming a molded body by heating and pressurizing the mixture
Data Source
AI summary
A method for manufacturing a molded body, includes a deposition step of depositing a mixture containing fibers and a starch in air; a moisturizing step of applying water to the mixture; and a molding step of forming a molded body by heating and pressurizing the mixture to which the water is applied, and the starch has a value of 2,000 to 10,000, the value being represented by the following expression (I) and being obtained by measurement performed in accordance with the following measurement methods (1) to (4) using a rapid visco analyzer (RVA).5,000−30×T1−90×(T2−T1)+2×η1−15×η2 (I)In the expression (I), T1 represents a gelatinization start temperature (° C.), T2 represents a gelatinization peak temperature (° C.), η1 represents a gelatinization peak viscosity (mPa·s), and η2 represents a trough viscosity (mPa·s), and the measurement is performed such that (1) after a water suspension containing the starch at 25 percent by mass is charged in the RVA as a measurement sample, the temperature thereof is increased to 50° C. and then maintained for one minute; (2) the temperature of the measurement sample is increased from 50° C. to 93° C. over 4 minutes and then maintained at 93° C. for 7 minutes; (3) the temperature of the measurement sample is decreased from 93° C. to 50° C. over 4 minutes and then maintained at 50° C. for 3 minutes; and (4) in the above (2) and (3), a rotational speed of a measurement paddle of the RVA is set to 960 rpm for 10 seconds after the start of the viscosity measurement and is then set to 160 rpm 10 seconds thereafter.