Trimodal Diene Rubber Polymerization for Impact and Gloss

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Solution Overview

Problem

Existing methods for preparing diene-based rubber polymers struggle to simultaneously enhance both the impact strength and surface gloss of graft polymers, while also minimizing polymerization loss and improving preparation efficiency.

Innovation Solution

A method involving controlled addition of a diene-based monomer, molecular-weight regulator, initiator, and emulsifier at specific polymerization conversion rates to produce a trimodal diene-based rubber polymer, which is then graft-polymerized with aromatic and vinyl cyanide-based monomers to achieve improved impact strength and surface gloss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a diene-based rubber polymer with small particle diameter is prepared to improve impact strength, then impact strength is improved, but surface gloss deteriorates

Engineering Contradiction:

Improveimpact strengthVSAvoidsurface gloss

Core Design Contradiction:

StrengthVSShape

Solution Approach 1:

The patent applies segmentation by dividing the polymer particles into three distinct size ranges (small: 0.01-0.1 μm, medium: 0.1-1.0 μm, large: 1.0-10.0 μm) within a single polymer composition. This trimodal particle size distribution allows different particle sizes to fulfill different functions: small particles improve impact strength, while larger particles maintain surface gloss, thereby resolving the contradiction between impact strength and surface gloss

Inventive Principle:

Principle #1Segmentation

2Shape

If separate preparation of small and large particle diameter polymers is performed to achieve both impact strength and surface gloss, then both properties are improved, but preparing efficiency deteriorates

Engineering Contradiction:

Improvesurface glossVSAvoidpreparing efficiency

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The patent merges multiple preparation processes into a single polymerization reaction by simultaneously producing small, medium, and large particle diameter diene-based rubber polymers in one reactor. This is achieved through controlled addition of monomers and regulators at specific polymerization conversion rates, eliminating the need for separate preparation processes and improving preparing efficiency while maintaining both impact strength and surface gloss

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If conventional polymerization method is used to simplify the process, then ease of manufacture is improved, but polymerization loss increases

Engineering Contradiction:

Improveprocess simplicityVSAvoidpolymerization loss

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by adding a chain transfer agent before the main polymerization reaction to control molecular weight and reduce polymerization loss. Additionally, monomers and regulators are added at predetermined conversion rates (30-70%, 70-90%, 90-99%) to optimize reaction conditions and minimize losses, thereby reducing polymerization loss while maintaining ease of manufacture

Inventive Principle:

Principle #10Preliminary action

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

This approach allows for the simultaneous production of diene-based rubber polymers with varying particle diameters, resulting in graft polymers with excellent impact strength and surface gloss, while minimizing polymerization loss and enhancing preparation efficiency through improved latex and polymerization stability.

Implementation Method 1

adding each of a diene-based monomer, a molecular-weight regulator, an initiator, and an emulsifier to a reactor a first time and carrying out polymerization

Methodology Applied

Scientific EffectPolymerization: Chemical Bonding

Implementation Method 2

adding each of a diene-based monomer, a molecular-weight regulator, an initiator, and an emulsifier to a reactor

Methodology Applied

Scientific EffectEmulsion: Emulsion

Data Source

PatentUS12103998B2Method of preparing diene-based rubber polymer and method of preparing graft polymer including the diene-based rubber polymer

Publication Date: 2024.10.01 LG CHEM LTD

AI summary

Provided is a method of preparing a diene-based rubber polymer, which includes: adding each of a diene-based monomer, a molecular-weight regulator, an initiator, and an emulsifier to a reactor a first time and carrying out polymerization; adding a molecular-weight regulator to the reactor a second time when a polymerization conversion rate of 48 to 72% is reached and carrying out polymerization; adding a diene-based monomer to the reactor a second time when a polymerization conversion rate of 63 to 77% is reached and carrying out polymerization; adding each of an initiator and an emulsifier to the reactor a second time when a polymerization conversion rate of 68 to 81% is reached and carrying out polymerization; and adding each of an initiator and an emulsifier to the reactor a third time when a polymerization conversion rate of 85 to 91% is reached and carrying out polymerization.