Hydrolysed Wheat Protein Coating for Paper Viscosity Control
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Solution Overview
Problem
The paper industry faces challenges in replacing synthetic latex in coating compositions with environmentally friendly alternatives that maintain high dry matter content, low viscosity, and strong tear resistance, while reducing petroleum-derived products and production downtime.
Innovation Solution
A coating composition comprising modified starch and hydrolyzed wheat protein with a molecular mass between 7 and 1000 kDa, combined with a synthetic adhesive and mineral filler, achieving a dry matter content of 45-80% and low viscosity, which is applied to paper or cardboard to enhance tear resistance and printing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If soy proteins are used as a latex replacement in coating compositions, then the proportion of synthetic latex is reduced, but the coating slurry becomes extremely viscous or requires very low dry matter contents (38-44% DM)
Solution Approach 1:
The patent applies parameter changes by carefully controlling the degree of hydrolysis of wheat proteins to achieve a molecular mass between 7 and 1000 kDa, and by optimizing the dry matter content to 45-80%. These parameter adjustments resolve the viscosity issue while maintaining latex reduction, as the controlled hydrolysis creates proteins with optimal solubility and flow properties for coating applications.
Solution Approach 2:
The patent uses composite materials by combining hydrolyzed wheat proteins with modified starches and synthetic adhesives in specific ratios. This composite approach allows the wheat proteins to replace latex while the modified starch and adhesive components work together to maintain appropriate viscosity and coating performance, avoiding the extreme viscosity problems observed with soy proteins alone.
2Ease of manufacture
If cold-soluble starch is used in coating compositions, then the composition can be formulated, but the starch forms aggregates and requires high-shear mixers that most paper mills do not have
Solution Approach 1:
The patent applies parameter changes by using modified starch with controlled gelatinization properties and by adjusting the coating slurry temperature and composition. These changes allow the starch to dissolve and disperse properly without requiring high-shear mixing equipment, making the formulation process accessible to typical paper mills with standard mixing capabilities.
Solution Approach 2:
The patent uses modified starch as an intermediary component that facilitates homogeneous mixing and dispersion of coating ingredients without requiring high-shear equipment. The modified starch properties act as a mediator between the various coating components, enabling proper mixing and aggregation prevention through its controlled solubility and interaction with other ingredients.
3Object-generated harmful factors
If coating solutions have low dry matter content to decrease viscosity, then the viscosity is reduced, but water migrates into the paper sheet causing weakening, loss of gloss, and increased drying energy
Solution Approach 1:
The patent applies parameter changes by optimizing the dry matter content to 45-80% and controlling the molecular mass of hydrolyzed wheat proteins to 7-1000 kDa. These parameter adjustments achieve the dual benefit of maintaining low enough viscosity for high-speed coating while preventing excessive water migration into the paper, thereby preserving paper strength and reducing drying energy requirements.
Solution Approach 2:
The patent uses composite materials comprising hydrolyzed wheat proteins, modified starch, and synthetic adhesive in optimized ratios. This composite formulation creates a coating slurry with balanced rheological properties that maintains appropriate viscosity at high dry matter content, reducing water migration and its harmful effects on paper integrity while enabling efficient high-speed coating.
4Productivity
If high-speed coating is performed with blade or threaded rod, then coating speed is increased, but excessive shear forces cause turbulence, defects, and paper breakage
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity and molecular mass characteristics of the coating slurry components. The controlled viscosity and molecular mass of hydrolyzed wheat proteins (7-1000 kDa) reduce the slurry's sensitivity to shear forces, allowing high-speed coating with blades or threaded rods without causing turbulence, defects, or paper breakage, thus maintaining both productivity and reliability.
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 coating composition that maintains high dry matter, low viscosity, and strong tear resistance, enabling efficient coating at high speeds with reduced production downtime and energy consumption, while partially replacing latex and improving printability and paper integrity.
Implementation Method 1
Its function is to ensure cohesion between the different components of the paper composition and to bind them to the fibers
Implementation Method 2
Its function is to ensure cohesion between the different components of the paper composition and to bind them to the fibers
Implementation Method 3
binders including at least one modified starch and a hydrolyzed wheat protein
Data Source
AI summary
The present invention relates to a paper or cardboard coating composition having a dry matter content of between 45 and 80%, comprising i) binders which include at least one modified starch and one adhesive, ii) one hydrolysed wheat protein having a mean molecular mass of between 7 and 1000 kDa, and iii) a mineral filler, as well as the method for obtaining such a composition. The invention also relates to a method for coating or brightening of paper or cardboard, comprising the steps consisting of i) the provision of a composition according to the invention, and ii) the depositing of said composition on a paper or cardboard substrate and the paper or cardboard coating thus obtained. Finally, the invention relates to the use of a hydrolysed wheat protein in the replacement of latex in a paper or cardboard coating composition.