Rubber Composition Viscosity Control via Alpha-Olefin

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Solution Overview

Problem

Existing rubber compositions used in tires and other rubber articles face challenges in achieving both high breaking resistance and operability, with multicomponent copolymers providing improved durability but often resulting in increased unvulcanized viscosity, which hinders operability.

Innovation Solution

A rubber composition incorporating a multicomponent copolymer with a conjugated diene unit, non-conjugated olefin unit, and aromatic vinyl unit, along with an α-olefin of 50 to 1,000 number-average molecular weight, which reduces unvulcanized viscosity and enhances both breaking resistance and operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a multicomponent copolymer containing conjugated diene unit, non-conjugated olefin unit, and aromatic vinyl unit is used in rubber composition, then breaking resistance is improved, but unvulcanized viscosity increases and operability deteriorates

Engineering Contradiction:
Improvebreaking resistanceVSAvoidoperability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by carefully controlling the molecular weight, molecular weight distribution, and compositional ratios of the multicomponent copolymer. Specifically, it uses a copolymer with weight-average molecular weight of 100,000-1,000,000 and narrow molecular weight distribution (Mw/Mn ≤ 2.0), along with controlling the content of non-conjugated olefin units (40-90 mol%) and aromatic vinyl units (5-30 mol%), to achieve optimal balance between breaking resistance and operability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite rubber composition by combining the multicomponent copolymer with specific additives including silane-modified polysiloxane (5-50 parts by mass per 100 parts rubber), sulfur crosslinking agents, and fillers. This composite approach enhances breaking resistance while the silane-modified polysiloxane component helps maintain acceptable operability by modifying the viscosity characteristics of the compound

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS11655356B2Rubber composition and tire
Publication Date: 2023.05.23 BRIDGESTONE CORP

AI summary

Provided is a rubber composition that can achieve excellent breaking resistance while having high operability. A rubber composition comprises: a rubber component containing a multicomponent copolymer that contains a conjugated diene unit, a non-conjugated olefin unit, and an aromatic vinyl unit; and an α-olefin having a number-average molecular weight (Mn) of 50 to 1,000.