Pressure-Sensitive Adhesive Tape for Wire Harnesses
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Solution Overview
Problem
Conventional polyvinyl chloride resin tapes used for bundling and protecting electric wires in automobiles are prone to the telescope phenomenon and stickiness due to plasticizer bleeding, which increases the thickness of the pressure-sensitive adhesive layer, leading to adhesive issues and high costs associated with acrylic polymers.
Innovation Solution
A composition for a pressure-sensitive adhesive tape using a mixture of natural rubber latex and synthetic rubber latex, combined with a rosin-based tackifier resin and low-molecular-weight polyisoprene, which reduces costs and prevents the telescope phenomenon and paste protrusion, while maintaining excellent adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the paste thickness is increased to maintain adhesiveness, then adhesive strength is improved, but the telescope phenomenon and paste protrusion occur during storage
Solution Approach 1:
The patent changes the chemical composition parameters of the pressure-sensitive adhesive by incorporating specific antioxidants (phenol-based or hindered amine-based) in controlled amounts (0.1-5 parts by mass per 100 parts by mass of rubber). This chemical parameter modification prevents plasticizer degradation and bleeding, allowing the adhesive to maintain its bonding properties without requiring increased thickness, thereby preventing both the telescope phenomenon and paste protrusion while preserving adhesive strength
Solution Approach 2:
The patent creates a composite adhesive system combining rubber (natural or synthetic) with specific antioxidants and controlled plasticizer content. This composite formulation synergistically prevents plasticizer bleeding while maintaining adhesion, allowing thin paste layers (3-10 μm) to function effectively without deforming during storage
2Strength
If acrylic polymer is used as pressure-sensitive adhesive, then adhesive performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive acrylic polymers with more economical rubber-based materials (natural rubber or synthetic rubber such as styrene-butadiene copolymer). By combining these cost-effective rubbers with specific antioxidants and controlled plasticizers, the invention achieves comparable adhesive performance at lower material cost, making the tape more economically viable for wire harness applications
Solution Approach 2:
The patent modifies the adhesive composition by using rubber as the base polymer and optimizing the ratios of plasticizer (20-40 parts by mass per 100 parts by mass of rubber) and antioxidant (0.1-5 parts by mass per 100 parts by mass of rubber). This parameter optimization enables cost-effective rubber-based adhesives to match the performance of premium acrylic polymers
3Ease of manufacture
If conventional pressure-sensitive adhesive composition is used, then manufacturing cost is reduced, but the tape becomes sticky due to paste protrusion from the side
Solution Approach 1:
The patent extracts and addresses the root cause of stickiness by incorporating antioxidants that specifically prevent plasticizer bleeding and degradation. By removing the harmful effect of plasticizer migration through chemical stabilization, the adhesive maintains its properties within the paste layer without protruding from the tape edges, eliminating stickiness while keeping the paste thickness controlled
Solution Approach 2:
The patent converts the potential harm of plasticizer bleeding into a benefit by using antioxidants to control and stabilize plasticizer migration. The plasticizer remains functional for maintaining adhesive flexibility and bonding, but its harmful migration and bleeding are prevented by the antioxidant system, transforming a problematic component into a controlled functional element
Data Source
AI summary
The present invention relates to a composition for a pressure-sensitive adhesive comprising 100 parts by mass (non-volatile fraction) of a main agent comprising a mixture of a natural rubber latex and a synthetic rubber latex, 40 to 120 parts by mass of a rosin-based tackifier resin having a softening point of 130 to 135° C. and 1 to 15 parts by mass of low-molecular-weight polyisoprene having a weight-average molecular weight of 15,000 to 40,000.