Vinyl Chloride-Vinyl Acetate Copolymer Particles for Viscosity Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vinyl chloride-vinyl acetate copolymer compositions for paste PVC sols used in automobile underbody coatings and sealants face challenges with viscosity stability over time and mechanical strength, particularly at low temperatures, failing to meet market demands for strict stability requirements.
Innovation Solution
Vinyl chloride-vinyl acetate copolymer particles with a specific distribution of vinyl acetate residue units, polymerization degree, and primary particle diameter, combined with an alkyl sulfate ester salt, are developed to provide a paste PVC sol with minimal viscosity change and enhanced mechanical strength, suitable for automobile underbody coatings and sealants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional vinyl chloride-vinyl acetate copolymer compositions are used, then processing is simplified, but viscosity stability over time deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the vinyl acetate residue unit content distribution (continuous distribution with one local maximum in the range of 0-30% by weight), polymerization degree (1,500-3,000), and average vinyl acetate residue unit content (5-15% by weight). These specific parameter ranges resolve the contradiction by achieving viscosity stability without excessive compositional complexity
Solution Approach 2:
The patent incorporates an alkyl sulfate ester salt (0.5-2 parts by weight per 100 parts by weight of copolymer) to dynamically control the paste PVC sol properties. This dynamic component adjusts the system's rheological behavior over time, maintaining viscosity stability while allowing flexible formulation
2Strength
If low processing temperature is used, then energy consumption is reduced, but mechanical strength deteriorates
Solution Approach 1:
The patent changes the compositional parameters by incorporating vinyl acetate units (5-15% average content) into the polyvinyl chloride copolymer structure. This modification enables the material to achieve adequate mechanical strength at lower processing temperatures (typically 160-200°C) without sacrificing strength, as the vinyl acetate units provide gelation meltability that facilitates strength development at reduced temperatures
3Duration of action of moving object
If storage period is extended, then production flexibility is improved, but viscosity stability deteriorates
Solution Approach 1:
The patent applies preliminary action by incorporating the alkyl sulfate ester salt into the paste PVC sol formulation before storage. This pre-incorporated additive proactively prevents viscosity changes during extended storage periods, allowing the material to maintain stability for months or years without degradation, thus enabling production flexibility while preserving viscosity stability
Data Source
AI summary
To provide vinyl chloride-vinyl acetate copolymer particles, which have a small change with time in sol viscosity when kneaded together with a plasticizer and are excellent in the mechanical strength during low temperature processing, and applications represented by a coating agent, particularly an automobile underbody coating or an automotive sealant.Vinyl chloride-vinyl acetate copolymer particles comprising a vinyl chloride-vinyl acetate copolymers in which a vinyl acetate residue unit content is continuously distributed in a range of 0 to 30% by weight and the distribution has one local maximum, and which has an average polymerization degree of 1,500 to 3,000 and an average vinyl acetate residue unit content of 5 to 15% by weight, and wherein an average diameter of a primary particle of the vinyl chloride-vinyl acetate copolymers is from 1 to 2 μm.