Reinforcing Sheet for Resin Molded Products
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Solution Overview
Problem
Conventional methods for reinforcing resin molded products, such as using ribs or steel-plate reinforcing sheets, often result in impaired outer appearance and degradation or melting of resin plates when heated, and fail to maintain excellent reinforcing ability at high temperatures.
Innovation Solution
A reinforcing sheet comprising a constraining layer and a thermoplastic adhesive reinforcing layer, specifically a hydrogenated polymer of a conjugated diene with polyolefin and a tackifier, is used, which is stuck to a polypropylene plate and heated to 80°C for 10 minutes to achieve a bending strength at least double that of the un-reinforced plate, while maintaining adhesion and preventing degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ribs are molded integrally with a resin plate to reinforce it, then the reinforcement effect is achieved, but sinks occur in the surfaces resulting in impaired outer appearance
Solution Approach 1:
The reinforcing structure is divided into separate components: a reinforcing sheet with adhesive layer that is applied separately to the resin plate, rather than being molded integrally. This segmentation allows the reinforcing function to be achieved without the surface defects caused by integral rib molding.
Solution Approach 2:
An adhesive layer is introduced as an intermediary between the reinforcing sheet and the resin plate. This adhesive mediator enables the reinforcing sheet to be bonded to the plate surface without requiring integral molding, thus avoiding sink marks while maintaining reinforcement effectiveness.
2Strength
If a steel-plate reinforcing sheet is heated to 160 to 200°C to cure the reinforcing layer, then the reinforcement is effective, but the resin plate is degraded or melted
Solution Approach 1:
The curing temperature parameter is changed from high temperature (160-200°C) to low temperature (room temperature or slightly elevated). The adhesive layer is formulated to cure at these lower temperatures, enabling reinforcement without degrading or melting the resin plate.
Solution Approach 2:
A composite adhesive system is used comprising a base polymer and a curing agent that react at low temperatures. This composite material formulation enables the adhesive to achieve sufficient strength for reinforcement without requiring high temperatures that would damage the resin substrate.
3Strength
If a reinforcing sheet is placed in a high-temperature atmosphere to maintain reinforcement, then the reinforcing ability is maintained, but the resin plate is not melted yet the reinforcement must remain effective
Solution Approach 1:
The adhesive composition parameters are optimized to maintain bond strength at elevated temperatures. The polymer selection and crosslinking density are adjusted so that the adhesive remains effective in high-temperature service conditions without degrading the resin plate during normal operation.
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 provides a lightweight, high-temperature-resistant reinforcement with excellent outer appearance and bending strength, ensuring the resin molded product is not degraded or melted, while maintaining its reinforcing ability even at high temperatures.
Implementation Method 1
after being stuck to a polypropylene plate having a thickness of 2.0 mm and heated at 80° C. for 10 minutes
Data Source
AI summary
A reinforcing sheet for a resin molded product includes a constraining layer, and a reinforcing layer laminated on the constraining layer. After being stuck to a polypropylene plate having a thickness of 2.0 mm and heated at 80° C. for 10 minutes, the reinforcing sheet for a resin molded product has a bending strength at a displacement of 1 mm at 90° C. which is not less than double a bending strength of the polypropylene plate having a thickness of 2.0 mm at a displacement of 1 mm at 90° C.