Vinylidene Chloride Latex Coating for Crack-Resistant Blister Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vinylidene chloride copolymer films for blister packs face challenges in achieving high impact resistance, heat stability, and barrier properties without cracking or discoloration, particularly due to issues with coating thickness, composition, and crystallinity.
Innovation Solution
Adjusting the proportion of vinylidene chloride units, molecular weight, particle size, and surface tension of the copolymer latex within specific ranges, combined with controlled emulsion polymerization and surfactant use, to enhance impact resistance and barrier properties while maintaining heat stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of vinylidene chloride copolymer latex is coated to increase coating thickness, then barrier properties are improved, but cracks and crinkles occur during drying process
Solution Approach 1:
The patent applies parameter changes by carefully controlling the composition parameters of the vinylidene chloride copolymer latex, specifically the proportion of constituent units from different monomers and the molecular weight distribution. This optimization allows the coating to achieve high barrier properties without developing cracks or crinkles during drying, as the optimized composition provides better flexibility and drying characteristics.
2Reliability
If the composition of copolymer is changed to improve barrier properties per unit thickness, then barrier properties are enhanced, but discoloration resistance to light and heat deteriorates
Solution Approach 1:
The patent optimizes the compositional parameters of the copolymer by controlling the proportion of constituent units from vinylidene chloride and other monomers within specific ranges. This balanced composition achieves high barrier properties per unit thickness while maintaining adequate discoloration resistance to light and heat, preventing both excessive thickness requirements and severe discoloration.
Solution Approach 2:
The patent employs composite material principles by creating a copolymer consisting of multiple monomer units with different functions. The vinylidene chloride units provide barrier properties while other monomer units contribute to stability against light and heat, achieving a synergistic effect where the composite structure outperforms individual components.
3Reliability
If the proportion of vinylidene chloride units is increased to enhance barrier properties, then barrier properties are improved, but impact resistance decreases due to increased crystallinity
Solution Approach 1:
The patent optimizes the proportion of vinylidene chloride constituent units within a specific range rather than maximizing it. This controlled composition, combined with optimized molecular weight parameters, achieves high barrier properties while maintaining sufficient impact resistance by preventing excessive crystallinity that would make the coating brittle.
4Reliability
If a wax composition is added to vinylidene chloride copolymer latex, then barrier properties are enhanced, but impact resistance is drastically reduced and coating becomes brittle
Solution Approach 1:
The patent extracts or eliminates the wax composition from the vinylidene chloride copolymer latex formulation. By removing this problematic additive, the patent achieves high barrier properties through optimized copolymer composition alone, avoiding the brittleness and drastic reduction in impact resistance that wax addition causes.
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 resulting film exhibits high impact resistance immediately after coating and for a long period, with excellent barrier properties and heat stability, reducing cracks and defects.
Implementation Method 1
Plastic films coated with a vinylidene chloride copolymer latex have a characteristic of excellent barrier properties, and are used mainly for food packaging materials and medicament packaging materials in order to block oxygen and water vapor
Implementation Method 2
in the case where films are stored for a long period, crystallization, which is characteristic of vinylidene chloride copolymers, progresses, and the coating easily becomes brittle
Data Source
AI summary
Provided is a film for blister packs having barrier capability that is excellent in terms of impact resistance and thermal stability. Also provided is a vinylidene chloride polymer-containing latex that is ideal for producing the film. The coating layer of the film for a blister pack, and the latex, comprise a vinylidene chloride copolymer having a weight-average molecular weight, Mw, between 120,000 and 300,000 that is obtainable by emulsion polymerizing 70 to 95 parts by mass of vinylidene chloride and 30 to 5 parts by mass of one or more other monomer(s) copolymerizable with the vinylidene chloride, with the proviso that the total amount of vinylidene chloride and the other monomer(s) is 100 parts by mass.