HPMC Solubility via 3-Position Substitution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydroxypropyl methyl cellulose (HPMC) has limited solubility in organic solvents, leading to clogging issues during filtration and prolonged centrifugation times, which increases costs and alters physical properties when attempting to improve solubility by increasing methoxy and hydroxypropoxy group substitutions.
Innovation Solution
HPMC with a molar substitution of hydroxypropoxy groups between 0.1 and 0.5 and a specific ratio of 3-position to total hydroxypropoxy substitution of 0.12 or more, maintaining the existing degree of substitution, enhances solubility in organic solvents without altering physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the substitution degree of methoxy groups and molar substitution of hydroxypropoxy groups of HPMC is increased to improve solubility, then solubility in organic solvent is improved, but cost increases and physical properties (thermal gel properties and adhesiveness) change
Solution Approach 1:
The invention changes the distribution pattern of hydroxypropoxy group substitution positions rather than increasing the overall substitution degree. By controlling the molar fraction of 3-position substitution to be 0.12 or more, the patent achieves improved solubility while maintaining the original substitution degrees (DS of methoxy groups and MS of hydroxypropoxy groups), thus avoiding cost increase and physical property changes.
2Productivity
If HPMC is dissolved in organic solvent to increase coating rate, then coating productivity is improved, but undissolved matter causes filter clogging and prolonged centrifugation
Solution Approach 1:
The invention optimizes the substitution position distribution parameter (molar fraction of 3-position substitution ≥ 0.12) to achieve complete dissolution of HPMC in organic solvents. This eliminates undissolved matter, preventing filter clogging and reducing centrifugation time, thereby maintaining high coating productivity without reliability issues.
Data Source
AI summary
There are provided hydroxypropyl methyl cellulose (HPMC) having a high solubility in an organic solvent even when it has a degree of substitution (DS) of methoxy groups and a molar substitution (MS) of hydroxypropoxy group which are the same as those in the conventional art; and others. Specifically, there are provided HPMC having the MS of from 0.1 to 0.5; a ratio (referred to as "MF at 3-position/MS") of 0.12 or more, as calculated by dividing a molar fraction (referred to as "MF at 3-position") of anhydroglucose units in which only a hydroxy group at the 3-position carbon is substituted with a hydroxypropoxy group and none of hydroxy groups at the 2-position and 6-position carbons is substituted with a hydroxypropoxy group by the MS; and a viscosity at 20°C of from 1.0 to 50 mPa·s, as determined in a 2% by mass aqueous solution; and others.