Halogenated Rubber Seal Welding to Polyurethane

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Solution Overview

Problem

Conventional methods for joining rubber seals to thermoplastic polyurethane components in garments are labor-intensive and prone to leaks, lacking a robust and efficient welding solution.

Innovation Solution

The process involves halogenating the surface of natural rubber seals and directly welding the thermoplastic polyurethane components to the halogenated rubber surface using RF or impulse welding, eliminating intermediate layers and enhancing the thermoplastic properties of the rubber for a strong and leak-free join.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional adhesive and stitching methods are used to join rubber seals to polyurethane components, then the joining process is robust and produces reliable bonds, but the manufacturing process becomes labor-intensive and time-consuming

Engineering Contradiction:
Improvebond strength and leak-free joinVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical joining system (adhesive application, positioning, and stitching) with a thermal welding system. The polyurethane component is welded directly to the rubber seal using heat and pressure, eliminating the need for adhesives and stitching operations. This substitution transforms a multi-step mechanical process into a single-step thermal process, significantly improving productivity while maintaining bond reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state of the polyurethane component by heating it to its melting point during the welding process. This parameter change allows the polyurethane to transition from a solid state to a molten state, enabling it to flow and fuse with the rubber seal surface. After cooling, the polyurethane solidifies to form a strong, permanent bond, replacing the need for adhesive bonding.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If adhesive tape and stitching are used to join rubber and polyurethane, then the join can be made with existing methods, but the process is complex and requires multiple steps including careful positioning

Engineering Contradiction:
Improvesimplicity of joining processVSAvoidnumber of joining steps
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges multiple joining operations (adhesive application, positioning, bonding, and reinforcement stitching) into a single welding operation. The welding process simultaneously achieves positioning, bonding, and sealing in one step, eliminating the sequential complexity of the conventional multi-step process. This consolidation dramatically simplifies the manufacturing procedure while reducing the number of required operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces heat as an intermediary medium to facilitate the joining process. By applying heat to the polyurethane component, the process enables direct fusion between the polyurethane and rubber seal without requiring adhesive intermediaries. This thermal intermediary simplifies the joining mechanism by creating a direct molecular bond through melting and solidification, replacing the complex adhesive-stitching system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If rubber seals are joined to polyurethane using conventional methods, then the components can be assembled, but the joins may be prone to leaks and lack robustness

Engineering Contradiction:
Improveleak-free performanceVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical joining methods (adhesive bonding and stitching) with thermal welding to achieve superior seal integrity. The welding process creates a homogeneous molecular bond between the polyurethane and rubber seal, eliminating potential leak paths that may exist in mechanically joined assemblies. This substitution ensures leak-free performance while reducing manufacturing time through the elimination of multiple bonding steps.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes parameter changes in the polyurethane material by heating it above its melting point during welding. This thermal parameter change allows the polyurethane to become pliable and fuse completely with the rubber seal surface, creating a seamless, leak-proof joint. The subsequent cooling and solidification locks in this intimate bond, ensuring robust sealing performance that exceeds conventional joining methods.

Inventive Principle:
Principle #35Parameter changes

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 achieves a strong and leak-free bond between rubber and thermoplastic components, surpassing the strength and reliability of conventional adhesive-based methods, with demonstrated shear and peel strengths significantly higher than typical tape joints.

Implementation Method 1

the natural rubber seal has a halogenated surface and the process comprises the steps of bringing the polyurethane component into contact with the halogenated surface of the natural rubber seal and RF welding or impulse welding the polyurethane component to the halogenated surface of the rubber seal

Methodology Applied
Scientific EffectHalogenation:

Implementation Method 2

RF welding or impulse welding the polyurethane component to the halogenated surface of the rubber seal

Methodology Applied
Scientific EffectRF welding:

Implementation Method 3

RF welding or impulse welding the polyurethane component to the halogenated surface of the rubber seal

Methodology Applied
Scientific EffectImpulse welding:

Implementation Method 4

The thermoplastic polyurethane and halogenated rubber therefore fuse together during the welding step

Methodology Applied
Scientific EffectThermal fusion:

Data Source

PatentEP2178692B1A process for making a garment comprising a polyurethane component and a natural rubber seal
Publication Date: 2014.03.19 AVON POLYMER PROD LTD
  • EP2178692B1 patent drawingFigure 1
  • EP2178692B1 patent drawingFigure 2
  • EP2178692B1 patent drawingFigure 3

AI summary

A process for making an article comprising a thermoplastic component (4) and a rubber component (3) having an halogenated surface in which the thennoplastic component is welded directly to the halogenated surface of the rubber component by, for example, RF or impulse welding. The product comprises a rubber component having an halogenated surface and a thermoplastic component in which the halogenated surface of the rubber component and the thermoplastic component are fused together.