Alkyl-Modified PVA Thickening Without Crosslinking Agents
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Solution Overview
Problem
Existing alkyl-modified vinyl alcohol polymers face challenges in maintaining high water solubility while achieving superior thickening properties and water resistance, often requiring crosslinking agents and resulting in instability and insufficient water resistance in coatings and adhesives.
Innovation Solution
Development of an alkyl-modified PVA with a specific monomer unit structure, including a linear or branched alkyl group of 17-29 carbon atoms and a hydrophilic amide bond, which allows for high water solubility and water resistance without the need for crosslinking agents, enhancing thickening properties and storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the content of alkyl groups in alkyl-modified PVA is increased to improve thickening properties, then thickening properties are improved, but water solubility deteriorates
Solution Approach 1:
The patent introduces a specific parameter - the carbon atom number of alkyl groups (17-29 carbons) - to optimize the balance between thickening properties and water solubility. This parameter change allows the alkyl groups to provide sufficient hydrophobic interaction for thickening while maintaining appropriate water solubility through controlled length.
Solution Approach 2:
The patent creates a composite structure by combining alkyl groups with specific carbon chain lengths (17-29 carbons) with vinyl alcohol polymer chains. This composite approach allows the material to exhibit both the hydrophobic thickening properties of alkyl groups and the water solubility of the vinyl alcohol backbone, resolving the contradiction between these two properties.
2Reliability
If an ionic functional group is introduced into alkyl-modified PVA to improve water solubility, then water solubility is improved, but storage stability deteriorates due to binding with oppositely charged substances
Solution Approach 1:
The patent extracts the ionic functional groups from the alkyl-modified PVA structure to eliminate the stability problems they cause. By removing these groups while retaining the alkyl groups with 17-29 carbon atoms, the patent maintains water solubility and thickening properties without the adverse binding effects that compromise storage stability.
3Reliability
If crosslinking agents are used to improve water resistance of coating films, then water resistance is improved, but viscosity stability deteriorates and the process becomes more complex
Solution Approach 1:
The patent enables the alkyl-modified PVA to provide water resistance through its own molecular structure - specifically through the hydrophobic alkyl groups with 17-29 carbon atoms - without requiring external crosslinking agents. This self-service approach maintains viscosity stability while achieving the desired water resistance performance.
4Use of energy by stationary object
If drying is carried out at low temperatures to simplify the process, then energy consumption is reduced, but water resistance of the coating film becomes insufficient
Solution Approach 1:
The patent changes the molecular parameters of the PVA by introducing alkyl groups with specific carbon chain lengths (17-29 carbons), which fundamentally alters the drying and water resistance characteristics. This parameter change enables effective water resistance to be achieved at lower drying temperatures, reducing energy consumption while maintaining film performance.
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 alkyl-modified PVA effectively balances water solubility and water resistance, providing superior thickening properties and storage stability in applications such as coatings, adhesives, and films, while eliminating the need for crosslinking agents and improving initial adhesiveness and water repellency.
Implementation Method 1
alkyl-modified PVAs having an alkyl group introduced thereto are known to present an alkyl group (hydrophobic group) interaction in an aqueous solvent, thereby increasing thickening properties
Implementation Method 2
The alkyl-modified PVA effectively balances water solubility and water resistance, providing superior thickening properties and storage stability in applications such as coatings, adhesives, and films
Data Source
AI summary
An object of the invention is to provide a novel alkyl-modified PVA capable of exerting superior thickening properties while maintaining high water solubility, and also capable of having high water resistance in a state being hardened without using an especial crosslinking agent. In addition, another object is to provide a composition, a thickener, a coating material for papers, a coated paper, an adhesive and a film containing the alkyl-modified PVA. Provided is an alkyl-modified vinyl alcohol polymer containing (a) a monomer unit represented by the following general formula (I): wherein, R1 represents a linear or branched alkyl group having 8 to 29 carbon atoms; and R2 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and has a viscosity average degree of polymerization of no less than 200 and no greater than 5,000, a degree of saponification of no less than 20 mol% and no greater than 99.99 mol%, and a content of the monomer unit (a) of no less than 0.05 mol% and no greater than 5 mol%.