Thin Rubber Layer Adhesion on Resin Molded Bodies
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Solution Overview
Problem
Existing methods struggle to form a uniform crosslinked rubber layer with a thickness of 50 μm or less on a resin molded body, as they face challenges with rubber composition fluidity, limited resin-rubber compatibility, and restricted types of materials, making it difficult to achieve high adhesion and versatility.
Innovation Solution
A method involving the application of a rubber latex with added organic peroxide to a resin molded body, where crosslinking occurs to form a thin crosslinked rubber layer with high adhesion, using a peroxide crosslinking agent and optional co-crosslinking agents to enhance bonding, allowing for a uniform and thin crosslinked rubber layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If extrusion molding is used to reduce rubber layer thickness, then the thickness can be reduced, but the rubber layer becomes non-uniform and pulsating due to low fluidity
Solution Approach 1:
The patent changes the physical state of rubber from bulk composition to latex form, and changes the molding method from extrusion to dip coating. This parameter change enables formation of uniform thin rubber layers (50 μm or less) without the fluidity problems that plague extrusion molding. The latex formulation with specific solid content (10-60%) and viscosity parameters allows precise thickness control while maintaining uniformity.
Solution Approach 2:
The patent replaces the mechanical extrusion molding system with a chemical crosslinking system. Instead of relying on mechanical extrusion to form the rubber layer, the invention uses dip coating to apply latex followed by peroxide crosslinking to form the final rubber layer. This substitution eliminates the fluidity and pulsation problems inherent in mechanical extrusion.
2Strength
If miscibility-based bonding methods are used, then adhesion between resin and rubber is achieved, but material selection is limited and versatility is poor
Solution Approach 1:
The patent introduces peroxide crosslinking as an intermediary mechanism that bridges resin and rubber without requiring their direct miscibility. The peroxide penetrates both materials and creates crosslinked bonds that adhere the rubber layer to the resin substrate. This intermediary approach allows bonding of immiscible materials like polyolefin resins with various rubber latexes, greatly expanding material compatibility.
Solution Approach 2:
The patent changes the bonding mechanism from chemical miscibility to peroxide crosslinking. By controlling the peroxide concentration (1-10 parts by mass per 100 parts rubber latex) and crosslinking conditions, the invention achieves strong adhesion between resin and rubber regardless of their inherent compatibility. This parameter change enables universal application across different resin and rubber types.
3Strength
If reactive group methods are used to bond resin and rubber, then adhesion is achieved, but the types of resins and rubbers are greatly restricted
Solution Approach 1:
The patent uses peroxide as a universal intermediary that can bond any resin containing C-H bonds with any rubber latex. The peroxide generates radicals that abstract hydrogen from both resin and rubber, creating crosslinked bonds without requiring specific reactive groups. This eliminates the material restrictions of reactive group methods while maintaining strong bonding.
Solution Approach 2:
The patent creates a universal bonding system where peroxide crosslinking can bond any thermoplastic resin with any rubber latex. The method is not limited to specific functional groups or material pairs. This multi-functionality allows the same process to be applied across diverse materials, from polyolefins with various rubbers, achieving both strong adhesion and broad versatility.
4Reliability
If pre-vulcanized rubber members are used, then rubber properties are achieved, but thin film formation on resin members is impossible
Solution Approach 1:
The patent performs preliminary preparation of rubber latex with controlled formulation (solid content, viscosity, additives) before application. This preliminary action ensures the latex has optimal properties for thin film formation and subsequent crosslinking. The latex is prepared with specific parameters that enable uniform coating at 50 μm or less thickness while maintaining rubber elasticity and other desired properties.
Solution Approach 2:
The patent changes the rubber state from pre-vulcanized solid to uncrosslinked latex, enabling thin film formation. After coating, crosslinking is performed to achieve the desired rubber properties. This parameter change from solid to liquid latex form allows precise thickness control and uniform thin film formation that is impossible with pre-vulcanized rubber members.
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 method achieves a crosslinked rubber layer with high adhesion to the resin molded body, even at small thicknesses, ensuring strong bonding and improved durability, while allowing for a wide range of resin and rubber material compatibility.
Implementation Method 1
a crosslinking section in which a crosslinking reaction is performed in the uncrosslinked rubber layer
Implementation Method 2
utilizing a liquid composition containing a rubber latex and an organic peroxide as a crosslinking agent
Data Source
AI summary
The present invention provides a composite molded body in which a rubber layer in the form of a thin film is formed on a surface of a resin molded body and a production method therefor. According to an embodiment of the present invention, a liquid composition containing a rubber component such as a rubber latex and a peroxide is applied to a surface of a resin molded body such as a polyamide-based resin having an amino group, causing crosslinking to occur in an uncrosslinked rubber layer and forming a crosslinked rubber layer in the form of a thin film. When a co-crosslinking agent is used in combination, adhesion to the resin molded body can be improved even when the thickness of the crosslinked rubber layer is small.