Microfibrillated Cellulose Viscosity Control in Starch Adhesives
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Solution Overview
Problem
Starch-based adhesives face challenges in controlling gel temperature and viscosity, particularly in the manufacture of corrugated cardboards, due to the unpredictable effects of additives like borax and sodium hydroxide, which affect processing stability and adhesive performance.
Innovation Solution
Incorporating microfibrillated cellulose (MFC) into starch-based adhesive compositions to act as a rheology modifier and stabilizer, reducing the need for borax and sodium hydroxide, thereby controlling gel temperature and viscosity while enhancing adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If borax and sodium hydroxide are used to control gel temperature and viscosity in starch-based adhesives, then adhesive performance is improved, but processing stability deteriorates due to unpredictable effects and interactions between additives
Solution Approach 1:
The patent removes borax from the adhesive formulation, extracting the problematic additive that causes unpredictable gel temperature effects. The formulation relies on starch and MFC alone, eliminating the harmful interactions between borax and sodium hydroxide that compromise processing stability.
Solution Approach 2:
The patent changes the chemical composition parameters by replacing borax-based gel temperature control with MFC-based rheology modification. This parameter change shifts the control mechanism from chemical reactions (borax-sodium hydroxide interactions) to physical network formation (MFC-starch interactions), improving predictability and stability.
2Manufacturing precision
If MFC is added to starch-based adhesive to control gel temperature and reduce alkaline content, then processing control is improved, but viscosity stability may worsen without proper rheology modification
Solution Approach 1:
MFC serves multiple functions simultaneously: it acts as a rheology modifier to control viscosity, a gel temperature controller by reducing alkaline content requirements, and a stabilizer for the adhesive composition. This multi-functionality resolves the contradiction by providing both precision control and stability through a single additive.
Solution Approach 2:
The patent creates a composite adhesive system combining starch and MFC, where the two materials work synergistically. The MFC-starch composite provides both the desired gel temperature control and viscosity stability, as the MFC network structure complements the starch gelation process rather than interfering with it.
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
MFC stabilizes the viscosity of starch-based adhesives, allowing for better control over gel temperature, increased production speed, reduced adhesive consumption, and improved bond strength, resulting in higher-quality corrugated boards with reduced water defects and enhanced processing stability.
Implementation Method 1
The present invention generally relates to the use of MFC as a rheology modifying additive in adhesive compositions
Implementation Method 2
the starch granules will absorb the liquid of suspension available and swell, causing gelation of the suspension
Data Source
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AI summary
The present invention relates to starch-based adhesive compositions comprising microfibrillated cellulose ("MFC"). In addition to microfibrillated cellulose, these adhesive compositions comprise at least one starch and/or at least one starch derivative. The adhesive compositions have a reduced amount of caustic soda vis-a-vis adhesive compositions that do not comprise MFC as an additive. Borax or boric acid (or any derivative thereof) may be partially or fully replaced with microfibrillated cellulose, wherein MFC (contrary to borax) surprisingly does not significantly affect the gel temperature of the overall adhesive.