4-Methyl-1-Pentene Copolymer Oil for Cold-Storage Stability

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Solution Overview

Problem

Conventional lubricating oil compositions lack an optimal balance between storage stability at low temperatures and low temperature characteristics, particularly in maintaining viscosity and preventing gel or sediment formation.

Innovation Solution

A lubricating oil composition comprising a copolymer of 4-methyl-1-pentene and an α-olefin with specific constituent unit ratios and properties, combined with a base oil, to achieve reduced low temperature viscosity and improved storage stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a copolymer with high 4-methyl-1-pentene content (30-90 mol%) is used to improve low temperature characteristics, then low temperature viscosity decreases, but storage stability deteriorates due to gel or sediment formation

Engineering Contradiction:
Improvelow temperature viscosityVSAvoidstorage stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent changes the compositional parameters of the copolymer by limiting the 4-methyl-1-pentene content to 1-30 mol% (lower than conventional 30-90 mol%) and specifying the other monomer content to 70-99 mol%. This parameter optimization resolves the contradiction by finding the optimal balance point where low temperature viscosity improvement is achieved without compromising storage stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite lubricating oil composition combining the optimized copolymer with specific base oils (mineral oil, synthetic oil, or ester oil) in controlled ratios. This composite approach allows the copolymer to provide low temperature characteristics while the base oil matrix maintains storage stability, preventing gel or sediment formation.

Inventive Principle:
Principle #40Composite materials

2Temperature

If the copolymer content is increased to improve low temperature characteristics, then viscosity at -35°C decreases, but the risk of gel or sediment formation increases

Engineering Contradiction:
Improvelow temperature viscosity characteristicVSAvoidstorage stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent optimizes the copolymer content parameter to 0.1-50 parts by mass per 100 parts of base oil, and further refines the monomer composition parameters (4-methyl-1-pentene: 1-30 mol%, other monomer: 70-99 mol%). This dual parameter optimization ensures sufficient low temperature performance while maintaining reliability through proper composition control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by specifying precise compositional ranges for different components: the copolymer's monomer distribution, the base oil type selection, and their proportional relationships. This localized optimization of quality parameters ensures that each component contributes appropriately to both low temperature characteristics and storage stability.

Inventive Principle:
Principle #3Local quality

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

The composition exhibits enhanced low temperature viscosity characteristics, reduced startup losses, and improved fuel consumption while maintaining viscosity index, with no gel or sediment formation, ensuring excellent storage stability.

Implementation Method 1

forms no gel or sediment due to favorable solubility in base oil

Methodology Applied
Scientific EffectSolubility: Solvation

Data Source

PatentUS12460149B2Lubricating oil composition
Publication Date: 2025.11.04 MITSUI CHEMICALS INC

AI summary

An object of the present invention is to provide a lubricating oil composition that is particularly excellent in viscosity characteristics at a low temperature of −35° C., i.e., the lubricating oil composition inhibiting an increase in low temperature viscosity while securing a viscosity necessary at an elevated temperature, and being excellent in storage stability in a low temperature environment. The present invention relates to a lubricating oil composition including a copolymer (A) and a base oil (B), in which the copolymer (A) satisfies the following requirement (a-1), and the content ratio between the copolymer (A) and the base oil (B) is such that the copolymer (A) is in a range of 0.1 to 50 parts by mass per 100 parts by mass in total of the copolymer (A) and the base oil (B).(a-1) The copolymer (A) is a copolymer of 4-methyl-1-pentene and an α-olefin having 20 or less carbon atoms excluding 4-methyl-1-pentene, including a constituent unit derived from 4-methyl-1-pentene within a range of 1 mol % or more and less than 30 mol % relative to the total constituent units.