Borate Complexation with Polyols: Rheology Modification

Overview of Technical Issues:

Borate species must change the bonding state of polyol molecules in a controlled way, but the current complexation appears insufficient or overly sensitive, causing unstable viscosity or gel strength in the liquid phase; the goal is to achieve predictable rheology modification through borate–polyol complexation under the intended formulation conditions.

Solution directions generated for this problem

Problem Direction 1 :

ImproveBorate complexation equilibrium sensitivity
VS
ConstraintFormulation composition stability

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
A gait control method and device for a biped robot
Innovative Solution Refine solution

Preconditioned borate polyol concentrate for drift tolerant rheology control

Prebuild a buffered complex state
How to solve :
  • Make a borate polyol concentrate first at B:diol site ratio 0.18–0.28, pH 8.55–8.75, 25–35% solids, age 30–90 min at 25–35°C before final dilution
  • Use cis-diol rich polyol fraction such as sorbitol or low-MW PVA with borax plus boric acid buffer, then blend this masterbatch as 10–30% of final formula to lock borate speciation before co-solutes enter
  • Control by Raman 877/935 cm−1 ratio 0.85–1.10, Brookfield viscosity ±8% lot to lot, pH ±0.05, water Karl Fischer ±0.3%, and accept final viscosity drift under ±15% after ±0.5 pH or ±2 wt% water challenge
Expected Effect : viscosity reproducibility >90%;gel strength variation −40%;pH and water drift sensitivity cut by 30–50%
Risk Control :
  • premix overaging raises haze
  • buffer ratio drift shifts speciation
  • water pickup during storage

Problem Direction 2 :

ImproveEffective borate-polyol stoichiometric ratio
VS
ConstraintDosing and pH control precision

Inspiration 1 : Cross-domain reference

Application Principle: #10 Preliminary action
Cross-domain applicability Assess applicability
Composition comprising hydrocortisone
Innovative Solution Refine solution

Buffered borate-polyol concentrate for ratio-stable rheology setting

Prebuild a stable active concentrate
How to solve :
  • Make a borate-polyol concentrate at B:diol 0.28-0.35, pH 8.6-9.0, 25-35°C
  • Use sorbitol or mannitol as sacrificial binder, then dose concentrate at 5-15% into final batch
  • QC by pH, Brookfield viscosity, 11B NMR, accept ±5% active ratio and ±8% viscosity
Expected Effect : Final dosing error tolerance widened 3x, viscosity CV <8%, gel-strength drift cut 30-50%, pH sensitivity reduced to ±0.2
Risk Control :
  • premix aging shifts speciation
  • water pickup changes solids
  • co-solutes displace bound borate

Problem Direction 3 :

ImproveReversible crosslink density
VS
ConstraintFormulation composition stability

Inspiration 1 : Cross-domain reference

Application Principle: #3 Local quality
Cross-domain applicability Assess applicability
Converted starch and food comprising said converted starch
Innovative Solution Refine solution

Selective cis-diol polyol fraction for buffered borate rheology

Split polyol roles for stability
How to solve :
  • Formulate a reactive cis-diol fraction at 8-15% solids using sorbitol or guar cis-diol sites, while 85-92% of polyol is low-borate-affinity carrier such as glycerol or PEG-400
  • Premix borax or boric acid only with the reactive fraction at pH 8.6-9.1, 25-35°C, B:cis-diol molar ratio 0.18-0.30, then blend into bulk under 300-600 rpm for 10-15 min
  • Control by microdomain rheology window: Brookfield viscosity 2500-4000 mPa·s at 25°C, G' 120-250 Pa at 1 Hz, pH 8.7±0.2, water drift tolerance ±1.5 wt%, lot CV under 8%
Expected Effect : Crosslink density +30-60%, viscosity CV <8%, water tolerance about 2x, gel strength +25-40% vs uniform borate-polyol systems
Risk Control :
  • reactive fraction overloading
  • pH drift beyond window
  • cis-diol raw material variability

Problem Direction 4 :

ImproveReversible crosslink density
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #3 Local quality
Cross-domain applicability Assess applicability
Compositions of hyaluronan with high elasticity and uses thereof
Innovative Solution Refine solution

Dual-polyol functional partitioning for robust borate crosslinking

Partition formulation into two distinct polyol fractions with different roles
How to solve :
  • Designate primary polyol fraction (15–25 wt%) with high vicinal-diol density (e.g., glycerol, 1,2-propanediol) exclusively for borate complexation to form transient network
  • secondary polyol fraction (balance) uses mono-functional or ster
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