Structural Polyurethane Adhesive with Carbodiimide Modification
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Solution Overview
Problem
Conventional structural polyurethane adhesives require improved adhesive properties for bonding multiple members in structures like automobiles and buildings.
Innovation Solution
A structural polyurethane adhesive comprising a polyisocyanate component with a first isocyanate group-terminated urethane prepolymer from an aromatic polyisocyanate and a macropolyol, a second isocyanate group-terminated urethane prepolymer from an araliphatic or aliphatic polyisocyanate and a polyether polyol, and a carbodiimide-modified aromatic polyisocyanate, with specific ratios and molecular weight ranges, enhancing bonding capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-component curable structural polyurethane adhesive is used, then basic bonding functionality is achieved, but adhesive properties are insufficient for demanding structural applications
Solution Approach 1:
The patent applies composite materials by formulating the polyisocyanate component as a mixture of three distinct isocyanate components (first, second, and third) with different chemical characteristics and functions. This composite formulation combines the benefits of aromatic polyisocyanates (high strength), aliphatic/araliphatic polyisocyanates (weather resistance), and carbodiimide-modified products (reactivity control), achieving superior adhesive properties that no single component could provide alone.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the ratio of the second isocyanate component to the total isocyanate component content within 2-35 mass%. This quantitative parameter optimization balances the competing requirements of adhesive strength, flexibility, and durability, resolving the contradiction between improved adhesive properties and formulation complexity through data-driven composition design.
2Ease of manufacture
If the adhesive formulation is simplified, then manufacturing ease is improved, but adhesive properties deteriorate
Solution Approach 1:
The patent establishes a specific ratio range (2-35 mass% of the second isocyanate component to total isocyanate component) that defines the optimal formulation window. Within this parameter range, the adhesive achieves both excellent adhesive properties and reasonable manufacturing feasibility, as the formulation remains a standard two-component system despite the complex internal composition of the polyisocyanate component.
3Strength
If heavy loads are borne over long periods, then structural reliability is improved, but adhesive degradation accelerates
Solution Approach 1:
The patent uses composite materials to address long-term durability under load by combining three不同类型的isocyanate components, each contributing specific performance characteristics. The aromatic polyisocyanate provides high initial strength, the aliphatic/araliphatic polyisocyanate ensures weather and UV resistance for long-term stability, and the carbodiimide-modified component controls reactivity for sustained performance, collectively enabling the adhesive to maintain shear bond strength over extended service periods.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating the carbodiimide-modified aromatic polyisocyanate component, which provides controlled reactivity and stabilizes the curing process. This component acts as a buffer that prevents excessive crosslinking density and internal stress development during curing, thereby cushioning against adhesive degradation under long-term heavy loads and extending service life.
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 exhibits excellent bonding properties, capable of bearing heavy loads over long periods, with improved shear bond strength and cohesive failure characteristics, suitable for various structural applications.
Implementation Method 1
a first isocyanate group-terminated urethane prepolymer that is a reaction product of a first material polyisocyanate consisting of an aromatic polyisocyanate and a first material polyol containing a macropolyol
Implementation Method 2
a second isocyanate group-terminated urethane prepolymer that is a reaction product of a second material polyisocyanate consisting of an araliphatic polyisocyanate and/or an aliphatic polyisocyanate and a second material polyol containing a polyether polyol
Implementation Method 3
a third isocyanate component containing a carbodiimide-modified product of an aromatic polyisocyanate
Implementation Method 4
structural adhesive has been used for bonding a plurality of members in a structure formed from the members
Data Source
AI summary
A structural polyurethane adhesive contains a polyisocyanate component and a polyol component. The polyisocyanate component contains a first isocyanate component containing a first isocyanate group-terminated urethane prepolymer that is a reaction product of a first material polyisocyanate consisting of an aromatic polyisocyanate and a first material polyol containing a macropolyol, a second isocyanate component containing a second isocyanate group-terminated urethane prepolymer that is a reaction product of a second material polyisocyanate consisting of an araliphatic polyisocyanate and/or an aliphatic polyisocyanate and a second material polyol containing a polyether polyol having a number average molecular weight of 160 or more and 4900 or less, and a third isocyanate component containing a carbodiimide-modified product of an aromatic polyisocyanate. The ratio of the second isocyanate component with respect to the total amount of the first isocyanate component, the second isocyanate component, and the third isocyanate component is 2% by mass or more and 35% by mass or less.