Rubber Hose Compound for Fluoropolymer Adhesion Without Pretreatment
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Solution Overview
Problem
Fluoropolymers exhibit poor adhesion to non-fluorinated elastomers due to their anti-adhesive properties, leading to complex and costly pretreatment methods, and existing adhesion promoters are toxic, impractical, or reduce flexibility, especially with highly fluorinated polymers.
Innovation Solution
A rubber mixture comprising a DBU salt obtained from DBU and a monocarboxylic or dibasic acid, applied to a silica carrier, combined with fillers and a crosslinking system, provides ideal adhesion to highly fluorinated polymers without additional layers or toxic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluoropolymer layer is used for chemical and temperature resistance, then barrier effect and chemical resistance are improved, but adhesion to elastomer deteriorates
Solution Approach 1:
The patent introduces a silane-based adhesion promoter as an intermediary substance between the fluoropolymer layer and the elastomer layer. This adhesion promoter contains functional groups that can bond to both the fluoropolymer and the elastomer, creating a chemical bridge that overcomes the natural anti-adhesive properties of fluoropolymers. The adhesion promoter is applied to the elastomer surface before bonding, allowing it to penetrate and form covalent bonds with both materials, thus resolving the adhesion problem while maintaining the chemical resistance of the fluoropolymer layer.
2Strength
If physical or chemical pretreatment is applied to fluoropolymer surface, then adhesion is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the adhesion-promoting function from complex physical or chemical pretreatment processes and consolidates it into a single adhesion promoter chemical substance. Instead of requiring plasma etching equipment, sodium ammonia treatment facilities, or other complex pretreatment installations, the solution is delivered through a simple chemical composition that can be applied and cured in standard manufacturing processes. This extraction of the essential adhesion function reduces manufacturing complexity while maintaining effective adhesion.
3Strength
If adhesion promoters are added to elastomer mixture, then adhesion to fluoropolymer is improved, but toxicity and handling difficulty increase
Solution Approach 1:
The patent changes the chemical parameters of the adhesion promoter to achieve a balance between adhesion effectiveness and safety. Specifically, the invention uses silane-based compounds with controlled molecular structure and reactivity. The silane groups provide strong bonding capability to both fluoropolymer and elastomer, while the specific chemical composition and crosslinking behavior ensure that the promoter cures to form a stable, non-toxic network. This parameter optimization allows the adhesion promoter to deliver strong adhesion without the severe toxicity and handling difficulties associated with some alternative adhesion chemicals.
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 rubber mixture achieves strong and stable adhesion to highly fluorinated polymers, suitable for food and drinking water applications, without increasing production complexity or cost, and maintains flexibility.
Implementation Method 1
a bonding agent system which consists of at least one 1,8-diazabicyclo[5.4.0]undec-7-ene salt (DBU 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, wherein the carrier is silica
Implementation Method 2
a crosslinking system comprising at least one sulfur and/or at least one sulfur donor or a crosslinking system comprising at least one peroxide
Data Source
AI summary
The invention relates to a rubber mixture, in particular for a hose, having improved adhesion, in particular with respect to fluoropolymers. For this purpose, the rubber mixture is characterized by the following composition: at least one rubber and at least one filler and an adhesion promoter system, which 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 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, or wherein the cross-linking is produced by x-radiation or microwave radiation, and 0 to 300 phr of further additives.