Polymer composition, lubricant additive, viscosity index improver, lubricant composition, method for producing polymer composition, and method for producing macromonomer
A polymer composition, in which a differential distribution value in a differential molecular weight distribution curve of the polymer composition, as measured by gel permeation chromatography, satisfies Equation 1 and a maximum value of a normalized back-scattering intensity of a 35 wt % base oil solution of the polymer composition, where a size q of a scattering vector of small-angle X-ray scattering at 25° C. is in a range of 0.07 nm −1 or more and 2 nm −1 or less, is 40 cm −1 or more.
1. A polymer composition, comprising a (meth)acrylic copolymer A including;
a constituent unit derived from an alkyl methacrylate a1 of an alkyl group having 5 to 14 carbon atoms,
a constituent unit derived from an alkyl acrylate a2 of an alkyl group having 5 to 14 carbon atoms, and
a constituent unit derived from an alkyl acrylate a3 of an alkyl group having 1 to 4 carbon atoms,
wherein the (meth)acrylic copolymer A further comprises a graft copolymer structure including,
a constituent unit derived from a vinyl radical polymerizable monomer m1 as a main chain of the graft copolymer structure, and
a constituent unit derived from a macromonomer M other than the vinyl radical polymerizable monomer m1 as a branch component of the graft copolymer structure,
a differential distribution value in a differential molecular weight distribution curve of the polymer composition, as measured by gel permeation chromatography, satisfies Equation 1, and
a maximum value of a normalized back-scattering intensity of a 35 wt % base oil solution of the polymer composition is 40 cm −1 or more, where a size q of a scattering vector of small-angle X-ray scattering at 25° C. is in a range of 0.07 nm −1 or more and 2 nm −1 or less,
dMp 30/ dMp≥ 0.65 Equation 1
wherein in Equation 1,
dMp30 is a differential distribution value of molecular weight corresponding to 30% of a peak top molecular weight, as measured by gel permeation chromatography,
dMp is a differential distribution value of the peak top molecular weight, as measured by gel permeation chromatography, and
the 35 wt % base oil solution uses API standard Group III or Group III Plus as a base oil.
2. The polymer composition according to claim 1 ,
wherein the (meth)acrylic copolymer A includes 1 to 50% by mass of the constituent unit derived from the alkyl methacrylate a1 with respect to a total mass of the (meth)acrylic copolymer A.
3. The polymer composition of claim 1 ,
wherein the (meth)acrylic copolymer A includes 1 to 50% by mass of the constituent unit derived from the alkyl acrylate a2 with respect to a total mass of the (meth)acrylic copolymer A.
4. The polymer composition of claim 1 ,
wherein the (meth)acrylic copolymer A includes 30 to 80% by mass of the constituent unit derived from the alkyl acrylate a3 with respect to a total mass of the (meth)acrylic copolymer A.
5. The polymer composition according to claim 1 ,
wherein the (meth)acrylic copolymer A is a copolymer including a constituent unit derived from an alkoxyalkyl (meth)acrylate a4.
6. The polymer composition according to claim 5 ,
wherein the (meth)acrylic copolymer A includes 1 to 30% by mass of the constituent unit derived from the alkoxyalkyl (meth)acrylate a4 with respect to a total mass of the (meth)acrylic copolymer A.
7. The polymer composition according to claim 1 ,
wherein a normalized back-scattering intensity of a 35 wt % base oil solution of API standard Group III or Group III Plus of the polymer composition is 1 cm −1 or more, where a size q of a scattering vector of small-angle X-ray scattering at 100° C. is 0.1 nm −1 .
8. The polymer composition according to claim 1 ,
wherein a mass average molecular weight of the polymer composition, as measured by gel permeation chromatography, is 50,000 to 2,000,000.
9. The polymer composition according to claim 1 ,
wherein a molecular weight distribution of the polymer composition, as measured by gel permeation chromatography, is 5 to 20.
10. The polymer composition according to claim 1 ,
wherein the vinyl radical polymerizable monomer m1 is an contains the alkyl acrylate a2 of an alkyl group with 5 to 14 carbon atoms and an the alkyl acrylate a3 of an alkyl group with 1 to 4 carbon atoms.
11. The polymer composition according to claim 1 ,
wherein the macromonomer M includes a constituent unit derived from a vinyl radical polymerizable monomer m2.
12. The polymer composition according to claim 11 ,
wherein the vinyl radical polymerizable monomer m2 includes the alkyl methacrylate a1 of an alkyl group with 5 to 14 carbon atoms.
13. The polymer composition according to claim 1 ,
wherein the macromonomer M has a structure of Formula 2 below,
In the formula, X 1 to X n-1 each independently represent a hydrogen atom, a methyl group, or CH 2 OH, Y 1 to Y n each independently represent a substituent bonded to a vinyl group of the vinyl radical polymerizable monomer m2, Z represents a terminal group, and n represents an integer of 2 to 10,000.
14. The polymer composition according to claim 1 ,
wherein a number average molecular weight of the macromonomer M, as measured by gel permeation chromatography, is 500 to 30,000.
15. A lubricant additive comprising:
the polymer composition according to claim 1 .
16. A viscosity index improver comprising:
the polymer composition according to claim 1 .
17. A friction modifier comprising:
the polymer composition according to claim 1 .
18. A lubricant composition comprising:
the polymer composition according to claim 1 .
19. A method for producing the polymer composition according to claim 1 ,
wherein the polymer composition is produced by polymerizing a monomer mixture including a macromonomer and a vinyl radical polymerizable monomer in a base oil, and
the macromonomer is a macromonomer polymerized in the base oil.
20. The method for producing a polymer composition according to claim 19 ,
wherein an α-methylstyrene dimer is used as a chain transfer agent.
21. A lubricant composition comprising:
the polymer composition according to claim 1 ; and
a lubricant base oil.
22. A polymer composition comprising a (meth)acrylic copolymer A including,
a constituent unit derived from an alkyl methacrylate a1 of an alkyl group having 5 to 14 carbon atoms,
a constituent unit derived from an alkyl acrylate a2 of an alkyl group having 5 to 14 carbon atoms, and
a constituent unit derived from an alkyl acrylate a3 of an alkyl group having 1 to 4 carbon atoms,
the (meth)acrylic copolymer A further comprises a graft copolymer structure including,
a constituent unit derived from a vinyl radical polymerizable monomer m1 as a main chain of the graft copolymer structure, and
a constituent unit derived from a macromonomer M other than the vinyl radical polymerizable monomer m1 as a branch component of the graft copolymer structure, and
the (meth)acrylic copolymer A includes 1 to 50% by mass of the constituent unit derived from the alkyl methacrylate a1 with respect to a total mass of the (meth)acrylic copolymer A.
23. The polymer composition according to claim 22 ,
wherein a differential distribution value in a differential molecular weight distribution curve, as measured by gel permeation chromatography, satisfies Equation 1
dMp 30/ dMp≥ 0.65 Equation 1
wherein in Equation 1
dMp30 is a differential distribution value of molecular weight corresponding to 30% of a peak top molecular weight
dMp is a differential distribution value of the peak top molecular weight.