Ether composition and solution composition

1. An ether composition comprising

a polyether compound (A) containing at least three —(OCF 2 CF 2 )— units, containing no —OCF 2 O— structure and having an average molecular weight of higher than 2,000 and at most 20,000, and

an ether compound (B) containing at least one —(OCF 2 CF 2 )— unit and having an average molecular weight of at most 2,000,

wherein the polyether compound (A) comprises one or more of compounds represented by the following formula (A-1) having an average molecular weight of higher than 2,000 and at most 20,000 and/or one or more of compounds represented by the following formula (A-2) having an average molecular weight of higher than 2,000 and at most 20,000:

(HOCH 2 CF 2 O(CF 2 CF 2 O) d1 —) 3 Y 3   (A-1)

(HOCH 2 CF 2 O(CF 2 CF 2 O) d2 —) 4 Y 4   (A-2)

wherein Y 3 is a perfluoroalkane triyl group, Y 4 is a perfluoroalkane tetrayl group, d1 is a positive number of at least 1, and d2 is a positive number of at least 1.

2. The ether composition according to claim 1 , wherein the polyether compound (A) has an average molecular weight of higher than 2,000 and at most 20,000 and a molecular weight distribution (M w /M n ) of from 1.05 to 1.65.

3. The ether composition according to claim 1 , wherein the absolute viscosity of the polyether compound (A) at 20° C. is at least 1,500 mPas, and the absolute viscosity of the ether composition at 20° C. is lower by at least 200 mPas than the absolute viscosity of the polyether compound (A) at 20° C.

4. The ether composition according to claim 1 , wherein the ether compound (B) is any one or more selected from compounds represented by the following formulae (B-1) to (B-6):

HOCH 2 CF 2 O(CF 2 CF 2 O) d3 —Y 10   (B-1)

(HOCH 2 CF 2 O(CF 2 CF 2 O) d4 —) 3 Y 11   (B-2)

HOCH 2 CF 2 O(CF 2 CF 2 O) d6 (CF 2 O) g1 CF 2 CH 2 OH  (B-3)

HOCH 2 CH(OH)CH 2 OCH 2 CF 2 O(CF 2 CF 2 O) d7 (CF 2 O) g2 CF 2 CH 2 OCH 2 CH—(OH)CH 2 OH  (B-4)

HOCH 2 CH 2 OCH 2 CF 2 O(CF 2 CF 2 O) d8 (CF 2 O) g3 CF 2 CH 2 OCH 2 CH 2 OH  (B-5)

(HOCH 2 CF 2 O(CF 2 CF 2 O) d9 —) 2 Y 12 (—O(CF 2 CF 2 O) d10 OCF 3 )  (B-6)

wherein

in the formula (B-1), Y 10 is a C 1-6 perfluoroalkyl group, d3 is a positive number of at least 1, and the average molecular weight of the compound represented by the formula (B-1) is from 1,000 to 2,000;

in the formula (B-2), Y 11 is a perfluoroalkane triyl group, d4 is a positive number of at least 1, and the average molecular weight of the compound represented by the formula (B-2) is from 500 to 2,000;

in the formula (B-3), d6 is a positive number of at least 1, g1 is a positive number of at least 0, and the average molecular weight of the compound represented by the formula (B-3) is from 500 to 2,000;

in the formula (B-4), d7 is a positive number of at least 1, g2 is a positive number of at least 0, and the average molecular weight of the compound represented by the formula (B-4) is from 500 to 2,000;

in the formula (B-5), d8 is a positive number of at least 1, g3 is a positive number of at least 0, and the average molecular weight of the compound represented by the formula (B-5) is from 500 to 2,000; and

in the formula (B-6), each of d9 and d10 is a positive number of at least 1, Y 12 is a perfluoroalkane triyl group, and the average molecular weight of the compound represented by the formula (B-6) is from 500 to 2,000.

5. The ether composition according to claim 1 , wherein the absolute viscosity of the ether compound (B) at 20° C. is less than 1,000 mPas.

6. The ether composition according to claim 1 , wherein the amount of the ether compound (B) is from 1 to 49 mass % based on the polyether compound (A).

7. The ether composition according to claim 1 , which has an absolute viscosity at 20° C. of at most 2,000 mPas.

8. The ether composition according to claim 1 , which has an average molecular weight of from 1,000 to 20,000, and a molecular weight distribution (M w /M n ) of from 1.02 to 1.7.

9. A process for producing the ether composition as defined in claim 1 , which comprises mixing the polyether compound (A) with the ether compound (B).

10. A lubricant containing the ether composition as defined in claim 1 as an essential component.

11. A solution composition containing the ether composition as defined in claim 1 and a solvent.

12. The solution composition according to claim 11 , wherein the total concentration of the polyether compound is (A) and the ether compound (B) contained in the ether composition in the solution composition is from 0.005 to 50 mass %.