Viscosity-Index Improving Agent Copolymer for Engine Oil Viscosity Control
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Solution Overview
Problem
Current viscosity-index improving agents for engine oils are insufficient in achieving the required High Temperature High Shear (HTHS) viscosity at 100°C and kinematic viscosity at 40°C, leading to issues like oil leakage and poor engine startability in cold regions.
Innovation Solution
A viscosity-index improving agent comprising a copolymer with specific monomers, including polyolefin-based monomers and ester oil, which improves the HTHS viscosity and kinematic viscosity when added to engine oil compositions, along with additional additives such as detergents and antioxidants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the viscosity of engine oil is lowered to reduce fuel consumption, then fuel efficiency improves, but oil leakage and seizure occur
Solution Approach 1:
The patent changes the chemical composition parameters of the viscosity-index improving agent by specifying particular monomer ratios (polyolefin-based monomer 5-50 mol%, monomer with C4 alkyl group 30-70 mol%, and at least one of monomers with C2-C3 alkyl groups 5-60 mol%). This optimized composition allows the oil to achieve lower viscosity at operating temperature while maintaining adequate viscosity at low temperature, thus reducing fuel consumption without causing oil leakage or seizure
Solution Approach 2:
The patent creates a composite viscosity-index improving agent by copolymerizing multiple types of monomers with specific functional characteristics. The combination of polyolefin-based monomers (providing low-temperature performance), monomers with C4 alkyl groups (providing viscosity improvement), and monomers with C2-C3 alkyl groups (providing gelation control) creates a composite material that simultaneously achieves low viscosity and high reliability
2Use of energy by moving object
If the HTHS viscosity at 100°C is reduced to improve fuel efficiency, then fuel consumption decreases, but inadequate lubrication occurs
Solution Approach 1:
The patent optimizes the chemical structure parameters of the copolymer by controlling the types and ratios of constituent monomers. The specific combination of polyolefin-based monomers (formula 1), monomers with C4 alkyl groups (formula 2), and monomers with C2-C3 alkyl groups (formulas 3 and 4) creates a molecular structure that provides adequate HTHS viscosity for lubrication while allowing lower viscosity at operating temperature for fuel efficiency
3Ease of operation
If the gelation index is reduced to improve cold startability, then engine startability in cold regions improves, but viscosity control at operating temperature becomes difficult
Solution Approach 1:
The patent changes the gelation index parameter by incorporating specific monomers with C2-C3 alkyl groups (formulas 3 and 4) in controlled amounts (5-60 mol%). These monomers modify the gel structure of the oil, reducing the gelation index to improve cold startability while the overall copolymer composition maintains appropriate viscosity at operating temperature through the balanced inclusion of all monomer types
Data Source
AI summary
The present invention aims to provide a viscosity-index improving agent capable of providing a lubricating oil composition having an appropriate gelation index, an excellent HTHS viscosity at 100° C., and an excellent kinematic viscosity at 40° C. when the viscosity-index improving agent is added thereto. The present also aims to provide a lubricating oil composition containing the viscosity-index improving agent. The present invention relates to, for example, a viscosity-index improving agent containing a copolymer (A) and an ester oil (Z), the copolymer A containing, as constituent monomers, a polyolefin-based monomer (a) represented by the following formula (1), a monomer (b) represented by the following formula (2) in which R4 is a C4 alkyl group, and at least one of a monomer (c) represented by the following formula (3) and a monomer (d) represented by the following formula (2) in which R4 is a C2-C3 alkyl group:wherein R1 is a hydrogen atom or a methyl group; —X1— is a group represented by —O—, —O(AO)m—, or —NH—, A is a C2-C4 alkylene group, m is an integer of 1 to 10, and each A may be the same or different when m is 2 or more; R2 is a residue after removal of one hydrogen atom from a hydrocarbon polymer containing a 1,2-butylene group as a structural unit; and p represents a number of 0 or 1;wherein R3 is a hydrogen atom or a methyl group; —X2— is a group represented by —O— or —NH—; and R4 is a C2-C4 alkyl group;wherein R5 is a hydrogen atom or a methyl group; —X3— is a group represented by —O— or —NH—; R6 is a C2-C4 alkylene group; R7 is a C1-C8 alkyl group; and r is an integer of 1 to 20, and each R6 may be the same or different when r is 2 or more.