Bio-Based Hot-Melt Adhesive Composition for Bookbinding Open Time
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Solution Overview
Problem
Existing hot-melt adhesives used in bookbinding have low bio-based content and compromise application properties when attempting to increase bio-content, leading to issues like adhesive sticking during cutting and inadequate open time.
Innovation Solution
A hot-melt adhesive composition comprising ethylene-based copolymer, modified castor oil, tackifying resin, and wax, with specific ratios and contents, achieving a bio-based content of over 42%, suitable viscosity, and open time for effective bookbinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bio-based content of hot-melt adhesive is increased, then the environmental sustainability is improved, but the application properties (viscosity, open time) deteriorate
Solution Approach 1:
The patent uses a composite formulation combining multiple bio-based components: ethylene-vinyl acetate copolymer (40-60 wt%), modified castor oil (10-30 wt%), and rosin ester (10-30 wt%). This composite approach allows each component to contribute different properties, achieving both high bio-based content (≥42%) and proper application characteristics through synergistic interaction of materials
Solution Approach 2:
The patent optimizes specific parameters including vinyl acetate content (15-45 wt%) in the copolymer, hydrogenation degree of castor oil (≥85%), and melting index ranges for different EVA components. These parameter adjustments fine-tune the adhesive's viscosity and open time while maintaining high bio-based content, resolving the contradiction between sustainability and applicability
2Duration of action of moving object
If the open time of adhesive is extended, then the bonding flexibility is improved, but the adhesive sticks to the cutting knife during subsequent cutting
Solution Approach 1:
The patent controls open time (15-40 seconds) by adjusting the melting index of EVA components and the hydrogenation degree of castor oil. The first EVA has melting index 200-600 g/10min and second EVA has 1-50 g/10min, creating a balanced rheological profile that provides sufficient open time while preventing excessive adhesion to cutting tools
3Productivity
If the viscosity of hot-melt adhesive is reduced for easier application, then the application speed is improved, but the adhesion strength to substrate decreases
Solution Approach 1:
The adhesive combines ethylene-vinyl acetate copolymer for base viscosity and adhesion, modified castor oil for flow properties and bio-based content, and rosin ester for tackifying and bonding strength. This composite system achieves optimal viscosity for application while maintaining strong substrate adhesion through synergistic material interactions
Solution Approach 2:
The patent uses different EVA components with distinct melting indices (first EVA: 200-600 g/10min, second EVA: 1-50 g/10min) to create different functional zones in the adhesive - one providing flow and application properties, the other providing adhesion and bonding strength, resolving the viscosity-strength contradiction
Data Source
AI summary
The invention relates to a hot-melt adhesive composition comprising: (a) an ethylene-based copolymer, (b) a tackifying resin, (c) a modified castor oil, (d) a wax, (e) optional additives, wherein the modified castor oil is characterized as being solid at 25°C, the modified castor oil contains hydrogenated castor oil, the ethylene-based copolymer is a copolymer of ethylene and carboxylic acid ester having an ethylenic double bond, and the hot-melt adhesive composition has a bio-based content of more than 42%, preferably more than 45%, more preferably more than 50%. The invention also relates to an article comprising at least one substrate and the hot-melt adhesive composition, and to a use of the hot-melt adhesive composition.