Butyl Rubber Molecular Weight Control for Processability

Overview of Technical Issues:

The molecular weight regulating agent insufficiently controls polymer chain termination uniformly across the reactor, resulting in broad molecular weight distribution in the butyl rubber product; this causes inconsistent processability where high molecular weight fractions create excessive viscosity during mixing and calendering while low molecular weight fractions compromise mechanical strength, and the goal is to achieve narrow molecular weight distribution for stable processing behavior and balanced final properties.

Solution directions generated for this problem

Problem Direction 1 :

ImproveRegulating agent distribution uniformity
VS
ConstraintMixing energy consumption

Inspiration 1 : Cross-domain reference

Application Principle: #19 Periodic action
Cross-domain applicability Assess applicability
Gas turbine and operating method thereof
Innovative Solution Refine solution

Pulsed regulator dosing with low-hold circulation for narrow butyl rubber MWD

Pulse dose then coast mix
How to solve :
  • Inject regulator micro-batches in 6-10 pulses over 20-40% conversion, each pulse 5-15 s with 30-60 s low-hold mixing
  • Use existing agitator with short high-shear bursts at 1.4-1.8x base rpm, then 0.7-0.9x base rpm, keeping average power within +5%
  • Set QC by proxy control: reactor-zone regulator CV <10%, pulse mass tolerance ±2%, final PDI 2.0-2.5 by offline GPC, Mooney ML(1+8)100C within target ±8%
Expected Effect : regulator CV 30-40% to <10%, PDI 3.5-4.5 to 2.0-2.5, average mixing energy +0 to +5%, high-MW tail cut >40%, tensile >8 MPa, process viscosity variation -25 to -35% vs continuous mixing
Risk Control :
  • pulse timing drift
  • local overtermination near feed
  • valve fouling or delayed response

Problem Direction 2 :

ImproveRegulating agent distribution uniformity
VS
ConstraintEquipment system complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Method and apparatus for making a decision on a card
Innovative Solution Refine solution

Modular dip-tube microzone dosing for uniform chain-stop control

Split dosing into simple zones
How to solve :
  • Install 3 modular dip-tubes on one feed header, depths at top mid bottom, nozzle ID 1.0-1.5 mm and flow split 30:40:30
  • Prepare pre-diluted regulator at 5-10 wt% in process solvent, keep feed 15-25°C and line velocity above 0.8 m/s to avoid local overtermination
  • Run batch QC mapping with 6 grab samples in 10 min, accept regulator deviation within ±8%, final PDI 2.0-2.5 by GPC and Mooney variation within ±7%
Expected Effect : Zone deviation 30-40% to <8%, PDI 3.5-4.5 to 2.0-2.5, tensile >10 MPa, added hardware limited to 3 tubes and 1 splitter, CAPEX about 40-60% below full multi-point skid
Risk Control :
  • tube fouling by polymer gel
  • unequal branch flow drift
  • solvent compatibility and seal swelling

Problem Direction 3 :

ImproveMolecular weight distribution control precision
VS
ConstraintEquipment system complexity

Inspiration 1 : Cross-domain reference

Application Principle: #26 Copying
Cross-domain applicability Assess applicability
Estimation apparatus, estimation system, and computer-readable non-transitory medium storing estimation program
Innovative Solution Refine solution

Soft-sensor chain-stop control using existing reactor signals

Model MW from simple signals
How to solve :
  • Build a soft sensor linking torque, jacket duty, pressure, and feed history to Mw/PDI using 60-100 historical batches and offline GPC
  • Run feedforward plus trim control on existing DCS, updating chain-transfer agent every 30-60 s, trim step 2-5%, target cumulative dose error within ±3%
  • Set quality gates: predicted PDI 2.1-2.5, residual error RMSE ≤0.15 PDI, final Mooney ML(1+8,125C) within ±5 MU, verify by 3-zone grab samples and batch GPC
Expected Effect : PDI 3.5-4.5 to 2.1-2.5;spatial agent variation <10%;off-spec batches -40 to -60%;no new inline analyzer
Risk Control :
  • model drift after catalyst change
  • signal noise from fouling
  • proxy correlation weak at startup
Patsnap Eureka Solution