Fluoropolymer-Rubber Hose Bonding Without Surface Pretreatment
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Solution Overview
Problem
Existing multi-layer flexible hoses face challenges in achieving strong adhesion between fluoropolymer and non-fluorinated elastomer layers, particularly with highly fluorinated polymers, due to the 'Teflon effect' and the need for complex, expensive pretreatment methods, which are impractical and may compromise food and drinking water safety.
Innovation Solution
Incorporating a crosslinking system in the rubber layer with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) salt and/or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) salt, combined with a crosslinking agent such as sulfur, peroxide, or polyvalent metal oxide, to create an adhesion promoter system that ensures ideal bonding between the fluoroplastic and rubber layers without additional adhesion promoters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluoropolymer layer is used for chemical resistance and barrier properties, then chemical resistance is improved, but adhesion to elastomer layer deteriorates due to anti-adhesive properties
Solution Approach 1:
The patent introduces an adhesion promoter as an intermediary substance between the fluoropolymer layer and elastomer layer. This promoter contains functional groups that can chemically interact with both materials, creating a bridging effect that overcomes the natural anti-adhesive properties of fluoropolymers while maintaining their chemical resistance
Solution Approach 2:
The patent modifies the chemical composition parameters of the elastomer mixture by incorporating specific adhesion promoters with particular functional groups. This changes the chemical reactivity parameters of the elastomer surface, enabling it to form strong bonds with the fluoropolymer layer without compromising the fluoropolymer's chemical resistance properties
2Strength
If physical or chemical pretreatment methods are applied to fluoropolymer surface, then adhesion is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The adhesion promoter is incorporated into the elastomer mixture before the bonding process, performing the adhesion-enhancing action in advance. This eliminates the need for subsequent physical or chemical pretreatment steps on the fluoropolymer surface, simplifying the manufacturing process while maintaining strong adhesion
Solution Approach 2:
The patent extracts the adhesion-enhancing function from separate pretreatment processes and integrates it into the elastomer compound formulation itself. This consolidation removes the need for additional manufacturing steps and equipment while achieving the same or better adhesion results
3Strength
If adhesion promoters are added to elastomer mixture, then adhesion between layers is improved, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the concentration parameters of adhesion promoters in the elastomer mixture to achieve the minimum effective dosage. By carefully controlling these compositional parameters, strong adhesion is achieved while minimizing the quantity of expensive adhesion promoter material required
Solution Approach 2:
The patent develops a composite elastomer formulation that combines adhesion promoters with the base elastomer matrix in a synergistic manner. This composite approach maximizes the adhesion effectiveness per unit cost by leveraging the interactive effects between the promoter and elastomer components
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
This approach provides strong, durable adhesion between the fluoropolymer and elastomer layers, suitable for use in food and drinking water applications, without increasing production complexity or costs, and ensures the hose meets safety and regulatory standards.
Implementation Method 1
layer II comprises a crosslinking system containing at least one sulfur and/or at least one sulfur donor, or a crosslinking system containing at least one peroxide, or a crosslinking system containing at least one polyvalent metal oxide
Implementation Method 2
layer II contains an adhesion promoter system consisting of at least one 1,8-diaza-bicyclo[5.4.0]undec-7-ene salt (DBU salt) and/or at least one 1,5-diaza-bicyclo[4.3.[0]non-5-ene salt (DBN salt)
Data Source
AI summary
The invention relates to a multi-layer flexible hose, in particular a drinking water hose. In order to improve adhesion, the multi-layer flexible hose contains at least one layer I, constructed from at least one fluoropolymer, and at least one further layer II, constructed from at least one rubber, which layers are in direct contact with each other, wherein layer II contains an adhesion promoter system that consists of at least one 1,8-diazabicyclo[5.4.0]undec-7-ene salt (DBU salt) and/or at least one 1,5-diazabicyclo[4.3.0]non-5-ene salt (DBN salt), wherein the DBU salt was obtained from DBU and a monocarboxylic acid and/or a dibasic acid and wherein the DBU salt was applied to a carrier, and wherein the DBN salt was obtained from DBN and a monocarboxylic acid and/or a dibasic acid and wherein the DBN salt was applied to a carrier, and wherein layer II has a cross-linking system containing at least one sulfur and/or at least one sulfur donor or a cross-linking system containing at least one peroxide or a cross-linking system containing at least one polyvalent metal oxide or a cross-linking system containing at least one diisocyanate or a cross-linking system containing at least one resin or a cross-linking system containing at least one dioxime or a cross-linking system containing at least one bisphenol or a cross-linking system containing at least one multifunctional silane.