PE(DM) Terpolymer Tackifier for Rubber Conveyor Belt Adhesion

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Solution Overview

Problem

Existing rubber compounds for industrial conveyor belts and power transmission belts face challenges with insufficient tack, leading to layer separation during curing and manufacturing, and increased rolling resistance due to the use of tackifiers like hydrocarbon resins and phenolic resins.

Innovation Solution

Incorporating propylene-α-olefin-diene (PE(D)M) terpolymers as tackifiers in the rubber compounds, which improves tack, reduces viscosity, and maintains strength and roll resistance properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrocarbon resins and phenolic resins are added as tackifiers to enhance rubber tack, then the tack of the rubber compound is improved, but the rolling resistance increases due to higher hysteresis/energy dissipation

Engineering Contradiction:
ImprovetackVSAvoidrolling resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the molecular weight parameter of the tackifier from conventional lower molecular weight (hydrocarbon and phenolic resins) to higher molecular weight (10,000-1,000,000 g/mol). This parameter change reduces hysteresis and energy dissipation while maintaining adequate tack, thereby resolving the contradiction between improving tack and reducing rolling resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite tackifier system combining higher molecular weight polymers (polyethylene, polypropylene, or their copolymers) with specific glass transition temperatures. This composite material approach achieves both sufficient tack and reduced energy loss by selecting materials with optimized molecular structure and thermal properties.

Inventive Principle:
Principle #40Composite materials

2Reliability

If hydrocarbon resins and phenolic resins are added as tackifiers to enhance rubber tack, then the tack of the rubber compound is improved, but the cure properties are significantly influenced

Engineering Contradiction:
ImprovetackVSAvoidcure properties
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the tackifier from conventional resin types (hydrocarbon, phenolic) to higher molecular weight polymers with specific functional groups. This parameter change reduces interference with cure chemistry while maintaining tack, as the higher molecular weight polymers have fewer reactive end groups that would interfere with vulcanization.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional tackifiers are used to improve rubber tack, then the tack is enhanced, but the manufacturing precision deteriorates due to layer separation during curing

Engineering Contradiction:
ImprovetackVSAvoidlayer separation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the molecular weight parameter to higher values (10,000-1,000,000 g/mol), which provides sufficient tack to hold layers together during curing without excessive softness that would cause deformation. This parameter change prevents layer separation while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4010421B1Propylene-alpha-olefin-diene terpolymer additive for improving rubber tack
Publication Date: 2025.05.21 EXXONMOBIL CHEMICAL PATENTS INC
  • EP4010421B1 patent drawingFigure 1
  • EP4010421B1 patent drawingFigure 2~4
  • EP4010421B1 patent drawingFigure 5

AI summary

A rubber compound suitable for making industrial conveyor belts and power transmission belts may comprise: 100 parts by weight per hundred parts by weight rubber (phr) of a rubber; and 1 phr to 30 phr of a propylene-α-olefin-diene (PE(D)M) polymer comprising 65 wt% to 97.5 wt% propylene, 2.5 wt% to 35 wt% C2 or C4-C20 α-olefin, and 0.2 wt% to 20 wt% diene, said wt% based on the weight of the PE(D)M polymer, and wherein the PE(D)M polymer has (a) Mooney viscosity (ML(1+4) @ 125°C) of 1 to 100, (b) melt flow rate of 0.1 g/min to 100 g/min, and (c) a weight average molecular weight to n- average molecular weight (Mw/Mn) ratio of 1.5 to 3.0.