Stampable Sheet Composite Fiber Structure for Tearing Resistance
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Solution Overview
Problem
Expansion molded products made from stampable sheets used in automobile interior and exterior materials face issues with sound absorption, rigidity, and resistance to tearing and cracking under bending deformation, particularly due to inadequate proportions and properties of inorganic and organic fibers, leading to reduced strength and increased likelihood of tearing.
Innovation Solution
A web and stampable sheet composition comprising a combination of inorganic and organic fibers, thermoplastic resin, and thermal expandable particles, with specific mass proportions and fiber lengths to enhance rigidity, sound absorption, and resistance to tearing, where the reinforcing fiber proportion is 20-55% and organic fiber proportion is 25-77% based on the total fiber and resin, with fibers having an average length of 8 mm or more and breaking elongation of 15% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If only inorganic fibers are used as reinforcing fibers, then the specific gravity is large, but the rigidity is lowered and the expansion molded product is easily torn when subjected to bending deformation
Solution Approach 1:
The patent uses a composite fiber structure combining inorganic fibers (glass fibers, carbon fibers) with organic fibers (polyester fibers, aramid fibers). This composite approach allows the material to achieve both low specific gravity and high strength properties, as the organic fibers provide flexibility and tear resistance while the inorganic fibers provide rigidity and structural stability.
Solution Approach 2:
The patent specifies precise parameter ranges: inorganic fiber content of 1-50 parts by mass per 100 parts of thermoplastic resin, organic fiber content of 1-50 parts by mass per 100 parts of thermoplastic resin, and fiber length of 5-100 mm. By optimizing these parameters, the material achieves the optimal balance between specific gravity, rigidity, and tear resistance.
2Strength
If the proportion of reinforcing fibers is too large, then the rigidity is improved, but the adhesion between reinforcing fibers is insufficient and the expansion molded product is easily torn
Solution Approach 1:
The patent optimizes the proportion of reinforcing fibers to 1-50 parts by mass per 100 parts of thermoplastic resin, and further specifies the ratio of inorganic to organic fibers. This parameter optimization ensures sufficient adhesion between fibers and resin while maintaining adequate rigidity, preventing the material from being easily torn.
Solution Approach 2:
The composite fiber structure with both inorganic and organic fibers provides multiple bonding interfaces with the thermoplastic resin. The organic fibers enhance adhesion through their chemical bonding capabilities, while the inorganic fibers provide structural integrity, together preventing fiber pull-out and material tearing.
3Ease of manufacture
If the average length of reinforcing fibers is short, then the manufacturing is easier, but the breaking elongation is small and the expansion molded product is easily torn when deformed
Solution Approach 1:
The patent specifies fiber length of 5-100 mm, which is longer than conventional short fibers but within a manageable range for manufacturing. This length range allows the fibers to provide adequate breaking elongation and tear resistance while remaining processable in standard fiber processing equipment.
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 solution results in an expansion molded product that maintains excellent sound absorption properties and rigidity while being resistant to tearing after repeated bending deformation, suitable for use in automobile interior and exterior materials.
Implementation Method 1
heating a stampable sheet, which is a sheet-shaped press molding material containing reinforced fibers and a thermoplastic resin as main materials, to make it bulky
Implementation Method 2
it is being used in automobile interior materials by taking advantage of its light weight and sound absorption properties
Data Source
AI summary
To provide an expansion molded product not only excellent in sound absorption properties and rigidity but also resistant to tearing after bending deformation, and a web and a stampable sheet suitable for producing the expansion molded product. The presently disclosed web, stampable sheet, and expansion molded product contain a reinforcing fiber containing an inorganic fiber and an organic fiber, a thermoplastic resin, and a thermal expandable particle, where the proportion of the reinforcing fiber is 20 mass % or more and 55 mass % or less based on a total amount of the reinforcing fiber and the thermoplastic resin, the proportion of the organic fiber is 25 mass % or more and 77 mass % or less based on a total amount of the organic and inorganic fibers, the reinforcing fiber has an average length of 8 mm or more, and the organic fiber has a breaking elongation of 15% or more.