Extruded Starch Acid Modification for Gypsum Board
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Solution Overview
Problem
Conventional methods for preparing pregelatinized, partially hydrolyzed starches are inefficient, leading to high water demand, increased energy costs, and slow production in gypsum board manufacturing, as they require excess water to maintain fluidity and result in lower output.
Innovation Solution
A method involving the mixing of non-pregelatinized starch with water and an acid, either weak or strong, to create a wet starch precursor with a moisture content of 8-25 wt%, which is then extruded at high temperatures to pregelatinize and acid-modify the starch in a single step, reducing water demand and enhancing production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pregelatinized starch is used in gypsum board manufacturing, then the starch provides binding and structural properties, but the water demand increases and production efficiency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the starch through acid hydrolysis to alter its molecular structure and gelatinization properties. This chemical modification changes the starch parameters to achieve lower water demand while maintaining binding properties, directly resolving the contradiction between reliability and productivity.
Solution Approach 2:
The patent employs preliminary action by pregelatinizing the starch before use in gypsum board manufacturing. The acid-modified starch is pre-treated to develop desired gelatinization characteristics, allowing it to provide binding properties with reduced water demand during the actual manufacturing process, thereby improving production efficiency.
2Ease of operation
If excess water is added to maintain slurry fluidity with conventional starch, then the starch disperses properly, but energy costs increase due to extended drying time
Solution Approach 1:
The acid modification of starch changes its physical and chemical parameters, including gelatinization temperature and water absorption characteristics. This allows the starch to achieve proper dispersion and slurry fluidity with reduced water content, directly lowering the energy required for drying while maintaining ease of operation.
3Ease of manufacture
If conventional pregelatinization methods are used, then the starch is processed, but production output is limited and manufacturing speed is slow
Solution Approach 1:
The patent applies preliminary action by pre-modifying starch with acid to achieve pregelatinization before use. This pre-treatment allows the starch to be more readily processed and integrated into the gypsum board manufacturing process, increasing production output and manufacturing speed while maintaining ease of manufacture.
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 method results in a pregelatinized, partially hydrolyzed starch with low water demand, higher output, faster production, and improved energy efficiency, while maintaining desired properties like viscosity and cold water solubility, ultimately enhancing the strength and manufacturing efficiency of gypsum boards.
Implementation Method 1
acid-modifying the wet starch precursor in the extruder at a die temperature of about 150° C. (about 300° F.) to about 210° C. (about 410° F.)
Implementation Method 2
pregelatinizing and acid-modifying the wet starch precursor in the extruder at a die temperature of about 150° C. (about 300° F.) to about 210° C. (about 410° F.)
Data Source
AI summary
Disclosed are methods relating to an extruded pregelatinized, partially hydrolyzed starch prepared by mixing at least water, non-pregelatinized starch, and acid to form a starch precursor. The acid can be a weak acid that substantially avoids chelating calcium ions or a strong acid in a small amount. In the method, pregelatinization and acid-modification of the starch precursor occurs in one step in an extruder. Also disclosed are methods of preparing board using the starch prepared according to the methods, as well as starches and boards prepared by various methods of the invention.