Grafted Polyvinyl Alcohol Adhesive for Creping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Unmodified polyvinyl alcohol (PVOH) adhesives used in creping processes face issues such as high shipping costs due to low concentration in aqueous solutions, viscosity increases over time leading to handling difficulties, and irreversible gel formation, which affects creping performance and results in waste.
Innovation Solution
A grafted polyvinyl alcohol polymer with side chains of aliphatic carboxylic acid, aliphatic amide, hydroxylated alkyl (meth)acrylate, or alkyl amino (meth)acrylate units is developed, allowing for higher concentrations in water-based solutions, improved storage stability, and reduced viscosity, enabling effective creping without gel formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If unmodified PVOH is used as creping adhesive, then cost-effectiveness and availability are improved, but the adhesive forms hard and uneven films that build up on the dryer, resulting in poor creping performance
Solution Approach 1:
The patent applies composite materials by combining PVOH with graft copolymers containing hydrophobic side chains. This composite structure allows the adhesive to maintain cost-effectiveness while preventing the hard film buildup that causes poor creping performance. The hydrophobic grafts modify the film-forming characteristics to reduce buildup on the dryer surface.
Solution Approach 2:
The patent changes the chemical parameters of PVOH by introducing graft copolymers with different hydrophobicity levels. This parameter modification allows tuning of the adhesive properties to achieve optimal balance between cost-effectiveness and creping performance, preventing the hard uneven film formation of unmodified PVOH.
2Quantity of substance
If concentrated PVOH is shipped to the mill, then shipping costs are reduced, but the low concentration in aqueous solutions (8 wt %) significantly increases shipping costs
Solution Approach 1:
The patent changes the concentration parameter by formulating high-concentration PVOH adhesives (greater than 8 wt %, up to 40 wt % or more). This allows significantly reduced shipping costs while maintaining effective adhesive performance through the graft copolymer modification that prevents film buildup issues.
Solution Approach 2:
The patent discards the water dilution approach used in conventional 8 wt % PVOH solutions. By recovering and concentrating the PVOH to higher levels with graft copolymer additives, the formulation eliminates the need for excessive water shipping while maintaining adhesive effectiveness.
3Stability of the object's composition
If aqueous solutions of PVOH are stored, then viscosity increases over time reaching 2000-100000 cP·s, but this leads to handling difficulties at the mill
Solution Approach 1:
The patent changes the rheological parameters of PVOH aqueous solutions by incorporating graft copolymers. This modification maintains storage stability while preventing the excessive viscosity increase (2000-100000 cP·s) that causes handling difficulties, keeping the adhesive pumpable and manageable at the mill.
4Duration of action of stationary object
If aqueous solutions of PVOH are stored for extended periods, then irreversible gelation occurs, but this renders the PVOH useless as an adhesive
Solution Approach 1:
The patent applies beforehand cushioning by adding graft copolymers to PVOH aqueous solutions before storage. This preventive measure cushions against the irreversible gelation that would otherwise occur during extended storage, maintaining adhesive functionality throughout the storage period.
Solution Approach 2:
The patent changes the chemical composition parameters by introducing graft copolymers that interfere with the gelation mechanism of PVOH. This parameter modification extends the storage duration before gelation occurs while preserving adhesive functionality, preventing the irreversible loss of usefulness.
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 grafted polyvinyl alcohol polymer provides a cost-efficient, stable, and high-concentration adhesive that maintains low viscosity and prevents irreversible gelation, enhancing creping performance and reducing waste, while allowing for better handling and application in creping processes.
Implementation Method 1
Graft polymerization of vinylic monomers such as vinyl acetate, vinyl pyrrolidone, ethylene, and vinyl esters
Data Source
AI summary
A grafted polyvinyl alcohol polymer includes a polyvinyl alcohol main chain and a plurality of side chains grafted to the polyvinyl alcohol main chain. One or more of the side chains from the plurality of side chains include one or more units selected from: an aliphatic carboxylic acid, an aliphatic amide, an amino alkyl (meth)acrylate, a hydroxylated alkyl (meth)acrylate, or any combinations thereof. The grafted polyvinyl alcohol polymer can be included in a formulation that also includes water, and the formulation can be used as an adhesive in a creping process.