Laser Bonding Screening Method for Thermoplastic Laminate
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Solution Overview
Problem
Existing laminate bonding methods require a bonding sheet, increasing raw material and production costs, and it is challenging to directly and firmly bond two materials using laser light without an adhesive.
Innovation Solution
A screening method for directly bonding two members by selecting thermoplastic polymers based on the Hansen solubility parameter distance and work of adhesion, ensuring the formula A = −9 × D + Wa − 45 is greater than zero, where D represents the solubility parameter distance and Wa is the work of adhesion, allowing for strong laser bonding without a bonding sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bonding sheet is used to bond the upper member and lower member by laser light, then the bonding quality is improved, but the raw material cost and production cost increase
Solution Approach 1:
The invention extracts and removes the bonding sheet from the laminate structure, enabling direct bonding between the upper member and lower member through laser light. The upper member contains a laser-absorbing substance that allows direct laser bonding without requiring a separate bonding sheet, thereby eliminating the additional raw material cost and production complexity associated with the bonding sheet.
Solution Approach 2:
The laser-absorbing substance embedded in the upper member acts as an intermediary that enables direct bonding. This substance absorbs the laser light and converts it to heat, facilitating the bonding process between the upper member and lower member without requiring a separate bonding sheet material.
2Reliability
If a bonding sheet is used to bond the upper member and lower member by laser light, then the bonding quality is improved, but the production process complexity increases
Solution Approach 1:
The bonding sheet is extracted and removed from the production process. The upper member itself is modified to contain a laser-absorbing substance, which enables direct bonding between members. This eliminates the need for operations involving sandwiching and positioning a separate bonding sheet, thereby reducing production process complexity.
3Quantity of substance
If two materials are directly bonded by laser light without a bonding sheet, then the material cost is reduced, but the bonding strength is insufficient
Solution Approach 1:
The upper member is designed with local quality differentiation: it contains a laser-absorbing substance concentrated at the bonding surface or in specific regions. This localized presence of the absorbing substance ensures that laser energy is effectively converted to heat at the bonding interface, achieving strong bonding between the upper member and lower member while maintaining cost efficiency.
Solution Approach 2:
The invention changes the physical and chemical parameters of the upper member by incorporating a laser-absorbing substance. This modification alters the laser light interaction properties of the material, enabling effective heat generation and direct bonding with sufficient strength. The bonding strength is enhanced through optimized parameters of the absorbing substance and laser irradiation conditions.
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
This method enables the firm bonding of two members without a bonding sheet, reducing material costs and allowing for the use of the laminate in severe environments, such as shoe soles, with bonding strengths of 3 kgf/2 cm or more.
Implementation Method 1
a first member which contains a first thermoplastic polymer and through which laser light can be transmitted and a second member which contains a second thermoplastic polymer and that can absorb laser light
Implementation Method 2
bonded by irradiation of laser light
Implementation Method 3
the bonding using laser light involves melting a thermoplastic material and welding two materials
Data Source
Figure 1~3
Figure 4~6
Figure 7~8
AI summary
A laminate of the present invention includes a first member which contains a thermoplastic polymer and through which laser light is transmitted and a second member which contains a thermoplastic polymer and absorbs laser light, wherein the first member is directly bonded to the second member, and A represented by the A=−9×D+Wa−45 is more than zero. D represents a distance between a Hansen solubility parameter of the thermoplastic polymer of the first member and a Hansen solubility parameter of the thermoplastic polymer of the second member, and Wa represents work of adhesion calculated from each surface free energy of the first member and the second member. Such a first member and a second member are firmly bonded to each other without using a bonding sheet.