Halogenated Vinyl Polymer Dispersion for Blister Pack Coating
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Solution Overview
Problem
Existing vinylidene chloride-based copolymer latexes suffer from issues such as foaming during shaping, leveling failure, and loss of transparency due to inappropriate surface tension and crystallinity, which affect the recoatability and barrier properties of multilayer films.
Innovation Solution
A halogenated vinyl polymer water dispersion is formulated with a vinylidene chloride polymer and an anionic amphiphilic compound, sodium dodecylbenzene sulfonate, at a specific concentration range (0.3 to 1.5 mass%) to achieve excellent coatability and prevent foaming during film shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of amphiphilic compound is added to promote polymerization, then polymerization progresses suitably, but foaming occurs during shaping and recoatability becomes unsatisfactory
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of the amphiphilic compound within a specific range (0.3-1.5 mass%) rather than using a large amount. This quantitative parameter optimization resolves the contradiction by finding the optimal concentration that ensures suitable polymerization progress while preventing foaming during shaping and maintaining good recoatability.
2Reliability
If recoating is performed to form a thicker barrier layer, then gas barrier properties are improved, but coated surface external appearance deteriorates and transparency is lost
Solution Approach 1:
The patent applies parameter changes by optimizing the amphiphilic compound concentration to achieve excellent recoatability. This enables multiple coating layers to be formed with smooth, uniform surfaces that maintain good external appearance and transparency even when forming thicker barrier layers for enhanced gas barrier properties.
3Ease of operation
If high temperature shaping is performed to shape blister pack, then shaping is achieved, but foaming occurs in film
Solution Approach 1:
The patent applies parameter changes by controlling the amphiphilic compound concentration within the optimal range of 0.3-1.5 mass%. This parameter optimization prevents foaming during high-temperature shaping while maintaining the film's ability to be shaped into blister packs, resolving the contradiction between shaping capability and foaming prevention.
4Reliability
If vinylidene chloride-based copolymer latex is used for packaging, then high barrier properties against water vapor and oxygen are achieved, but surface tension is inappropriate causing leveling failure and orange peel pattern
Solution Approach 1:
The patent applies the intermediary principle by introducing an amphiphilic compound as a surface-active substance that modifies the surface tension of the vinylidene chloride-based copolymer latex. This intermediary substance acts as a mediator between the polymer and the coating process, enabling appropriate wetting and leveling while maintaining the high barrier properties of the original polymer system.
Solution Approach 2:
The patent applies parameter changes by optimizing the concentration of the amphiphilic compound to achieve appropriate surface tension. This parameter optimization resolves the contradiction by adjusting the surface tension within an appropriate range that enables proper leveling and coating uniformity while preserving the high barrier properties of the vinylidene chloride copolymer.
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 solution provides a uniform coating film without leveling failure, orange peel patterning, or foaming, enhancing the recoatability and barrier properties of the multilayer films, particularly suitable for blister packs for medications.
Implementation Method 1
compounding a specific amount of a specific amphiphilic compound with a halogenated vinyl polymer water dispersion... sodium dodecylbenzene sulfonate... to achieve excellent coatability and prevent foaming during film shaping
Implementation Method 2
A multilayer film comprising a layer obtained by applying a halogenated vinyl polymer water dispersion onto a base film... provides a uniform coating film without leveling failure, orange peel patterning, or foaming
Data Source
Figure 1A~1C
Figure 2A~2C
AI summary
Provided is a water dispersion that has excellent coatability in recoating and that yields a uniform coating film without leveling failure, orange peel patterning, or the occurrence of foaming during film shaping. A halogenated vinyl polymer water dispersion contains a halogenated vinyl polymer and more than 0 mass% and less than 2.5 mass%, relative to resin solid content, of an anionic amphiphilic compound having a hydrophilicity index of less than 41.0.