One-Component Moisture Curing Adhesive for Vehicle Lighting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hot-melt adhesives used in vehicle lighting appliances exhibit inferior curing in deep portions and reduced hot strength when adhering lenses and housings, leading to non-uniform bonding and potential failures at elevated temperatures.
Innovation Solution
A one-component moisture curing adhesive composition comprising 100 parts of bifunctional polyether polyol, 80 to 40 parts of crystalline polyester polyol, 20 to 60 parts of non-crystalline polyester polyol, a polyisocyanate, and a curing catalyst, with a specific NCO/OH ratio of 1.2 to 1.5, providing high hot strength and superior curing in deep portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hot-melt adhesive is used to adhere lens and housing, then ease of manufacture is improved, but hot strength deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by specifying exact ratios of polyether polyol (100 parts), crystalline polyester polyol (80-40 parts), and non-crystalline polyester polyol (20-60 parts), along with polyisocyanate and curing catalyst, to achieve both ease of manufacture and high hot strength
Solution Approach 2:
The patent creates a composite adhesive system combining multiple polyol types (polyether and polyester) with polyisocyanate to achieve superior hot strength while maintaining ease of manufacture through the one-component moisture-curing formulation
2Strength
If reactive hot-melt adhesive is used to adhere lens and housing, then hot strength is improved, but curing in deep portions deteriorates
Solution Approach 1:
The patent replaces the conventional two-component reactive adhesive system with a one-component moisture-curing system that automatically cures through reaction with atmospheric moisture, eliminating the need for complex mixing and application equipment while achieving uniform curing in deep portions
Solution Approach 2:
The adhesive utilizes moisture from the atmosphere and deep portions of the assembly to self-cure without requiring external catalysts or complex application systems, enabling uniform curing throughout deep portions while maintaining high hot strength
3Ease of operation
If adhesive with low melt viscosity is used, then ease of operation is improved, but adhesive flow increases
Solution Approach 1:
The patent optimizes the melt viscosity parameter by carefully controlling the molecular weights and ratios of the polyol components, achieving a balance where the adhesive remains operable at appropriate temperatures but does not exhibit excessive flow at elevated temperatures
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 adhesive achieves high hot strength and superior curing in deep portions, preventing dripping and ensuring uniform bonding, even in complexly shaped vehicle lighting appliances, with a melt viscosity suitable for preventing adhesive flow.
Implementation Method 1
a content of the polyisocyanate (D) is such that a number of isocyanate groups included in the polyisocyanate (D) with respect to a total number of hydroxy groups included in the bifunctional polyether polyol (A), the crystalline polyester polyol (B), and the non-crystalline polyester polyol (C) satisfies NCO/OH=1.2 to 1.5
Implementation Method 2
a curing catalyst (E)
Data Source
AI summary
A one-component moisture curing adhesive for use in a vehicle lighting appliance including: 100 parts by weight of a bifunctional polyether polyol (A) having a molecular weight of not less than 3,000; from 80 to 40 parts by weight of a crystalline polyester polyol (B); from 20 to 60 parts by weight of a non-crystalline polyester polyol (C); a polyisocyanate (D); and a curing catalyst (E), wherein a content of the polyisocyanate (D) is such that a number of isocyanate groups included in the polyisocyanate (D) with respect to a total number of hydroxy groups included in the bifunctional polyether polyol (A), the crystalline polyester polyol (B), and the non-crystalline polyester polyol (C) satisfies NCO/OH=1.2 to 1.5; and a vehicle lighting appliance formed by adhering a lens and a housing the one-component moisture curing adhesive for use in a vehicle lighting appliance.