Two-Component Polyurethane Adhesive Strength and Extensibility
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Solution Overview
Problem
Two-component polyurethane adhesives face challenges in achieving high strength and extensibility simultaneously, which are essential for structural bonding applications, as they often compromise on either strength or elasticity.
Innovation Solution
A two-component polyurethane composition comprising a polyol component made from the reaction product of ricinus oil with ketone resins and an aliphatic triol, combined with an aromatic polyisocyanate, with a specific weight ratio and OH/NCO ratio, to achieve high tensile strength and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyol and polyisocyanate components are used to achieve rapid curing and high strength, then bonding strength is improved, but extensibility deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the polyol component by using reaction products of ricinus oil with ketone resins having specific OH numbers (110-200 mg KOH/g) and combining them with aliphatic triols in controlled ratios. This parameter optimization enables the adhesive to achieve both high strength and high extensibility simultaneously, resolving the contradiction between bonding strength and adaptability.
Solution Approach 2:
The patent creates a composite polyol system by combining reaction products of ricinus oil with ketone resins and aliphatic triols in specific weight ratios (A1/A2 = 4-50). This composite approach allows the adhesive to integrate the beneficial properties of different materials: the structural integrity from ricinus oil-based components and the elasticity from aliphatic triol segments, thereby achieving both high strength and extensibility.
2Strength
If high strength is achieved through optimized polyol and polyisocyanate ratios, then bonding strength is improved, but elasticity is compromised
Solution Approach 1:
The patent optimizes the OH/NCO ratio to specific ranges (1.05:1-1.15:1) and controls the weight percent ratio of aliphatic triol to reaction product (A1/A2 = 4-50). These parameter adjustments ensure that the crosslinking density is optimized for strength while preserving enough chain flexibility for elasticity, thus resolving the contradiction between tensile strength and elastic stability.
Solution Approach 2:
The patent introduces aliphatic triol segments (A2) as specific local structures within the polyol component that provide elastic properties. These triol segments act as flexible spacers within the crosslinked network, maintaining elasticity locally while the overall composition achieves high strength through the optimized ratio of rigid (A1) and flexible (A2) segments.
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 composition achieves high strength and elasticity, making it suitable for structural bonding applications without compromising on either property, with preferred ratios of aliphatic triol and aromatic polyisocyanate optimizing tensile strength, elongation at break, and E modulus.
Implementation Method 1
Two-component polyurethane adhesives based on polyols and polyisocyanates have already been used for a very long time
Implementation Method 2
the polyol component K1 comprises at least one reaction product of ricinus oil with ketone resins
Data Source
AI summary
The invention concerns two-component polyurethane compositions of a polyol component and a polyisocyanate component, the polyol component including at least one reaction product of castor oil and ketone resins with an OH number of 110 to 200 mg KOH/g, and at least one aliphatic triol, and the polyisocyanate component including at least one aromatic polyisocyanate, the ratio in weight percent of being between 4 and 50 and the ratio of all NCO groups of the aromatic polyisocyanates to all the OH groups totaling (A1+A2)=1.15:1-85:1, the aliphatic triol being-1,2,3-propane triol and/or-1,1,1-trimethylol propane and/or polyether polyols based on 1,1,1-trimethylol propane with a molecular weight of 170-500 g/mol and an OH-number of 400-1100 mg KOH/g, and the total of all the OH groups of (A1+A2) being ≧90% of the total of all the OH groups of the two-component polyurethane composition.