Shape-Formable Polyurethane Foam for Body-Conforming Cushions
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Solution Overview
Problem
Current shape-memory foams and low resilience urethane foams do not effectively demonstrate shape-followability when attached to the human body, as they lack the ability to significantly change hardness in response to temperature changes, which is essential for conforming to body surfaces.
Innovation Solution
A shape-formable resin foam with a glass transition temperature between 10° C. to 35° C., characterized by a large ratio of maximum to minimum storage modulus, allowing it to soften and deform easily when heated by the body, is developed. This foam is made from a polyether polyol-based flexible polyurethane foam with specific hydroxyl values and functional groups, and isocyanate index, enabling it to follow the shape of a contact target while maintaining resilience and low compression residual strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the glass transition temperature is lowered to enable easy deformation at body temperature, then shape-followability is improved, but the foam loses resilience and hardness at normal temperatures
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature within 10°C to 35°C and regulating the storage modulus ratio (G'max/G'min) between 3.0 to 30. This allows the foam to be firm at normal temperatures but soften easily at body temperature, achieving both resilience and shape-followability through thermal parameter control
Solution Approach 2:
The patent utilizes phase transitions by leveraging the glass transition temperature range of the foam. When the foam is at normal temperature, it remains in a firm phase providing resilience. When exposed to body temperature, it transitions to a softer phase enabling shape-followability, thus using thermal phase change to resolve the contradiction between firmness and adaptability
2Strength
If the storage modulus ratio is increased to maintain firmness at normal temperature, then hardness is improved, but the foam becomes difficult to deform at body temperature
Solution Approach 1:
The patent resolves this contradiction by optimizing the storage modulus ratio (G'max/G'min) to fall within 3.0 to 30. This parameter control ensures the foam maintains sufficient firmness at normal temperatures while being easily deformable at body temperature, achieving the right balance between hardness and softness through thermal parameter regulation
3Adaptability or versatility
If the foam is designed to be very soft to conform to body shape, then shape-followability is improved, but the foam cannot maintain structural integrity when detached
Solution Approach 1:
The patent uses phase transitions to resolve this contradiction. The foam maintains structural integrity in its firm phase at normal temperatures when detached. Upon contact with the body, it transitions to a softer phase that conforms to body shape, thus preserving both structural stability and shape-followability through thermal phase change
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 foam achieves excellent shape-followability, maintaining sufficient hardness for comfort and pressure distribution, with the ability to recover its shape easily when detached, providing a cushioning material with improved wearing feeling and shape-retaining performance.
Implementation Method 1
a glass transition temperature which is expressed as a temperature corresponding to a peak value of loss tangent is in the range from 10° C. to 35° C.
Implementation Method 2
the loss tangent at a temperature of 10° C. to 35° C. is in the range from 0.20 to 0.80, and a ratio (G′max/G′min) between the maximum value (G′max) and the minimum value (G′min) of the storage modulus (G′) at a temperature of 10° C. to 35° C. is in the range from 3.0 to 30
Data Source
AI summary
A foamed resin product having shape-formable properties, a method of using the same and a cushion material that is to be worn by the human body are provided. The foamed resin product (a flexible polyurethane foam, etc.) has a glass transition temperature, expressed as the temperature of the loss tangent peak, of 10° C. to 35° C., a loss tangent within this temperature range of 0.20 to 0.80, and, with respect to the storage elastic modulus (G′) within this temperature range, the ratio (G′max/G′min) of maximum value (G′max) to minimum value (G′min) of 3.0 to 30. The using method thereof has attaching a molded article made of the foamed resin product to the surface of the human body, and lowering the hardness of the molded article due to the heat transferred from the human body so as to deform the molded article by allowing to follow-up the shape of the body.