Gypsum Panel Strength via Calcium Hydrogen Phosphate Dihydrate

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Solution Overview

Problem

Gypsum wallboards face a challenge in enhancing core strength without compromising non-combustibility when using organic substances as strengthening agents, as they degrade the fire resistance and require restricted amounts, limiting the achievable strength.

Innovation Solution

Incorporating calcium hydrogen phosphate dihydrate as an inorganic strengthening agent into the gypsum slurry, which increases the compressive strength of the gypsum hardened body while maintaining non-combustibility and allowing for a low specific gravity, thereby addressing the need for a strengthening agent that does not affect fire resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If organic substances such as substituted starch are added to enhance core strength, then the compressive strength of the gypsum hardened body is improved, but the non-combustibility of the gypsum wallboard is degraded

Engineering Contradiction:

Improvecompressive strengthVSAvoidnon-combustibility

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameter by replacing organic strengthening agents with inorganic calcium hydrogen phosphate dihydrate, thereby maintaining strength enhancement while preserving non-combustibility. The specific parameter change is the substitution of carbon-containing organic compounds with inorganic phosphate compounds that do not compromise fire resistance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system by combining calcium hydrogen phosphate dihydrate with gypsum (calcium sulfate hemihydrate) to form a new strengthening agent composite. This composite maintains the fire-resistant properties of gypsum while incorporating the strength-enhancing characteristics of calcium hydrogen phosphate dihydrate, achieving both objectives simultaneously.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If the amount of substituted starch is restricted to maintain non-combustibility, then the compressive strength enhancement is limited, but the non-combustibility is maintained

Engineering Contradiction:

Improvenon-combustibilityVSAvoidcompressive strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The invention changes the chemical nature parameter from organic to inorganic, allowing full utilization of strengthening agent without the combustion risk that limits organic substances. By using calcium hydrogen phosphate dihydrate, the system can incorporate higher amounts of strengthening agent unrestricted by fire safety concerns, thereby achieving greater compressive strength enhancement.

Inventive Principle:

Principle #35Parameter changes

3Weight of moving object

If the specific gravity of the gypsum hardened body is decreased to improve thermal and sound insulation, then the physical strength decreases

Engineering Contradiction:

Improvespecific gravityVSAvoidphysical strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The invention uses a composite material approach by combining lightweight gypsum structure with calcium hydrogen phosphate dihydrate strengthening particles. This composite enables the gypsum hardened body to achieve low specific gravity for thermal and sound insulation while the inorganic strengthening agent provides the necessary physical strength that would otherwise be lost at lower densities.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the strengthening mechanism parameter by using inorganic calcium hydrogen phosphate dihydrate instead of organic additives, which allows the material to maintain high strength at lower specific gravity. The inorganic nature of the strengthening agent provides structural reinforcement that is not compromised by the reduced density, enabling simultaneous achievement of lightweight properties and mechanical strength.

Inventive Principle:

Principle #35Parameter changes

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 use of calcium hydrogen phosphate dihydrate enhances the compressive strength of gypsum hardened bodies by approximately 10-20% and suppresses deflection, improving dimensional stability and maintaining non-combustibility, making it suitable for applications requiring both strength and fire resistance.

Implementation Method 1

a gypsum slurry manufacturing step for manufacturing a gypsum slurry by mixing calcined gypsum, calcium hydrogen phosphate dihydrate, water, and foam

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 2

a hardening step for hardening the shaped body obtained in the shaping step to obtain the gypsum hardened body

Methodology Applied

Scientific EffectHydration reaction: Mineral Hydration

Data Source

PatentEP3492439B1Gypsum panel including gypsum hardened body, method for manufacturing gypsum panel, and use thereof

Publication Date: 2021.12.15 YOSHINO GYPSUM CO LTD

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AI summary

A gypsum hardened body including a gypsum slurry that has been hardened is provided. The gypsum slurry is obtained by mixing calcined gypsum, calcium hydrogen phosphate dihydrate, water, and foam The specific gravity of the gypsum hardened body is greater than or equal to 0.3 and less than or equal to 0.8.