Polyoxyalkylene Modified PVA for Inkjet Coating Crack Reduction
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Solution Overview
Problem
Existing vinyl alcohol-based polymers face challenges in forming ink jet recording materials with high gloss, high ink absorbency, and low crack formation, as well as in achieving sufficient grease resistance and waterproofness in release and greaseproof papers, due to issues with viscosity, temperature sensitivity, and permeability.
Innovation Solution
A polyoxyalkylene modified vinyl alcohol-based polymer with a viscosity average degree of polymerization between 150 and 5000, a degree of saponification of 40-99.99 mol %, and a POA group modification rate of 0.05-10 mol %, composed of polyoxypropylene and oxyethylene blocks, is developed to enhance temperature-sensitive thickening properties and improve handling and performance in ink jet recording materials, release paper, and greaseproof paper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyvinyl alcohol with high degree of polymerization is used to form coating film, then film strength is improved, but viscosity of coating liquid increases and handling becomes difficult
Solution Approach 1:
The patent applies parameter changes by modifying the degree of polymerization of polyvinyl alcohol to a specific range (150-5000) and controlling the POA group modification rate (0.05-10 mol%) to optimize the balance between film strength and coating liquid viscosity, resolving the contradiction between strength and handling properties
2Strength
If polyvinyl alcohol with high degree of polymerization is used, then film strength is improved, but production rate decreases due to long drying time
Solution Approach 1:
The patent changes the parameter of degree of polymerization to an optimized range (150-5000) that reduces drying time while maintaining film strength, and introduces POA groups to enhance water solubility and drying characteristics, thereby improving production rate without sacrificing strength
3Quantity of substance
If large amount of microparticles is used to form capillaries in ink receiving layer, then ink absorbency is improved, but binder ratio decreases and layer becomes rigid and crack-prone
Solution Approach 1:
The patent changes the parameter of binder molecular structure by introducing POA groups to polyvinyl alcohol, which improves the binder's flexibility and adhesion properties, allowing the ink receiving layer to maintain crack resistance even with high microparticle content while preserving ink absorbency
4Reliability
If coating film is cooled to low temperature to prevent cracks, then crack resistance is improved, but energy loss increases and production rate decreases
Solution Approach 1:
The patent extracts the cooling step from the coating process by introducing POA groups to polyvinyl alcohol, which provides inherent crack resistance through improved film flexibility and reduced internal stress, eliminating the need for energy-consuming cooling operations
Solution Approach 2:
The patent changes the chemical composition parameter of the binder by adding POA groups, which fundamentally alters the drying characteristics and stress development of the coating film, allowing crack-free drying at ambient temperatures without energy loss
5Ease of manufacture
If polyvinyl alcohol is used for release paper to improve film formation, then film formation ability is improved, but grease resistance and waterproofness are insufficient
Solution Approach 1:
The patent creates a composite structure by introducing POA groups (hydrophobic character) into polyvinyl alcohol (hydrophilic base), combining the film formation ability of PVA with the grease resistance of polyoxyalkylene groups to achieve both properties simultaneously
6Ease of operation
If conventional PVA is used for greaseproof paper, then ease of coating is maintained, but grease resistance and waterproofness are insufficient due to high permeability
Solution Approach 1:
The patent changes the chemical composition parameter of the coating polymer by introducing POA groups to PVA, which fundamentally alters the permeability characteristics and provides grease resistance while maintaining coating ease due to the polymer's water solubility and film-forming properties
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 polymer achieves a significant reduction in cracks during drying, enhances ink absorbency, improves grease resistance and waterproofness, and maintains high strength and stretching properties, thereby increasing production efficiency and product quality.
Implementation Method 1
PVA is also utilized for paper processing agents, textile sizing agent, dispersants, adhesives, films, and the like utilizing the excellent film formation ability, surfactant ability, hydrogen bond formation ability, and the like
Implementation Method 2
This recording material realizes both high ink absorbency and waterproofness by an ink absorbency mechanism utilizing the capillary action
Data Source
AI summary
Provided is a polyoxyalkylene modified vinyl alcohol-based polymer comprising a polyoxyalkylene group in a side chain, wherein the polymer has a viscosity average degree of polymerization of not less than 150 and not more than 5000, a degree of saponification of not less than 40 mol % and not more than 99.99 mol %, and a polyoxyalkylene group modification rate of not less than 0.05 mol % and not more than 10 mol %; and the polyoxyalkylene group is composed of a polyoxypropylene block and a (poly)oxyethylene block and is represented by the following general formula (I). Such polymer is excellent in temperature-sensitive thickening properties.(in the general formula (I), R1 denotes a hydrogen atom or an alkyl group having a carbon number of from 1 to 8; either one of R2 and R3 is a methyl group and the other is a hydrogen atom; and 10≦m≦40 and 1≦n≦50).