Wood-PVC Composite Material with Soft PVC for Crack Resistance
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Solution Overview
Problem
Wood-PVC composite materials from prior art are brittle, prone to cracking due to water absorption, and often exhibit shiny spots during manufacturing, which affects their durability and appearance.
Innovation Solution
A composite material comprising a mixture of natural fibers, hard PVC, and soft PVC, with specific proportions and hardness ranges, significantly reducing water absorption and energy requirements during injection molding, thereby enhancing break resistance and eliminating shiny spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wood fibers are combined with hard PVC to produce extruded materials, then structural strength is improved, but the material becomes brittle and prone to cracking
Solution Approach 1:
The patent combines hard PVC, soft PVC, and wood fibers in specific proportions (hard PVC: 30-70 wt%, soft PVC: 10-50 wt%, wood fibers: 10-50 wt%) to create a composite material that maintains structural strength while improving flexibility and reducing brittleness. The soft PVC component specifically addresses the brittleness issue by providing elastic properties to the otherwise rigid composite.
2Quantity of substance
If wood components are used in the composite material, then natural fiber content is improved, but water absorption increases leading to cracks
Solution Approach 1:
The soft PVC acts as an intermediary substance between the hydrophilic wood fibers and the environment, creating a hydrophobic barrier that reduces water absorption. The plasticizers in the soft PVC specifically target the wood fiber surfaces, forming a protective layer that prevents water penetration while maintaining the natural fiber content in the composite.
3Productivity
If injection molding is performed with conventional wood-hard PVC composite materials, then production is achieved, but high energy consumption and shiny spots occur
Solution Approach 1:
The patent modifies the material parameters by incorporating soft PVC with specific Shore hardness (40-80, preferably 65-75) and plasticizer content (10-50 wt%), which changes the rheological properties of the composite. This allows injection molding to be performed at lower temperatures and pressures, reducing energy consumption by approximately one-third compared to conventional hard PVC composites while eliminating shiny spots through reduced injection pressure.
Data Source
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AI summary
Composite material comprises natural fibers, hard PVC with a plasticizer fraction of 0-12 wt.% and soft PVC with shore hardness of 40-80.