Acrylic-ABS Polymer Adhesion to Non-DEHP PVC
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Solution Overview
Problem
The adhesion between non-di-(2-ethylhexyl)phthalate (DEHP) plasticized polyvinyl chloride (PVC) and acrylic- or ABS-based polymers deteriorates over time, leading to unsuitable shelf-life for medical devices bonded with these materials.
Innovation Solution
Improving adhesion by blending the acrylic- or ABS-based polymers with impact modifiers such as poly (butyl acrylate), poly (butyl methacrylate), polybutadiene, or methyl methacrylate-butadiene-styrene copolymer to increase the rubber content above 12% (w/w), which enhances the bond strength and longevity when solvent bonding with non-DEHP plasticized PVC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-DEHP plasticized PVC is solvent bonded to acrylic- or ABS-based polymer, then the medical device can be manufactured without DEHP, but the bond strength deteriorates over time leading to unsuitable shelf-life
Solution Approach 1:
The patent changes the chemical composition parameters of the acrylic- or ABS-based polymer by incorporating specific plasticizers and impact modifiers. This modifies the polymer's adhesion properties and chemical compatibility with non-DEHP plasticized PVC, enabling long-term bond strength retention without DEHP
Solution Approach 2:
The patent creates a composite polymer system by combining acrylic- or ABS-based polymer with specific plasticizers (adipates, sebacates, phosphates, citrates, or polyesters in 10-40 phr ranges) and impact modifiers (ethylene-vinyl acetate, ethylene-acrylic acid, or acrylic-ethylene copolymers at 5-20 phr). This composite formulation resolves the contradiction between DEHP-free requirement and long-term adhesion durability
2Strength
If DEHP plasticized PVC is used, then good initial adhesion to acrylic- or ABS-based polymer is achieved, but the bond decays over time
Solution Approach 1:
The patent extracts DEHP from the plasticized PVC formulation and replaces it with alternative plasticizers. This removal of the problematic DEHP component, combined with the modified acrylic- or ABS-based polymer formulation, prevents the bond decay mechanism while maintaining initial adhesion strength
Solution Approach 2:
The patent modifies the chemical parameters of both the PVC (alternative plasticizers) and the acrylic- or ABS-based polymer (specific plasticizer and impact modifier combinations) to create a compatible bonding system that maintains strength over time without DEHP
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 method maintains a bond force of at least 24.47 N (5.5 lbf) for 5 years and extends the lifespan of the bond, ensuring the durability and reliability of medical devices.
Implementation Method 1
improving adhesion by solvent bonding of non-di-(2-ethylhexyl)phthalate (DEHP) plasticized polyvinyl chloride (PVC) to an acrylic-based polymer or an ABS-based polymer
Data Source
Figure 1
AI summary
The present disclosure provides methods of improving adhesion of a non-di-(2- ethylhexyl)phthalate (DEHP) plasticized polyvinyl chloride (PVC) to an acrylic-based polymer or an ABS-based polymer. Such methods may comprise blending the acrylic-based polymer or ABS-based polymer with an impact modifier so that a rubber content in the acrylic-based polymer or ABS-based polymer is greater than 12% (w/w). Also provided are components of a device (e.g., a medical device) made by the disclosed methods.