Polycarbonate diol and polyurethane using same
View Patent ↗The present invention relates to a polycarbonate diol comprising a structural unit derived from a compound represented by the following formula (A) and a structural unit derived from a compound represented by the following formula (B), wherein the hydroxyl value is from 20 to 450 mg-KOH/g: HO—R 1 —OH (A) HO—R 2 —OH (B) the glass transition temperature of said polycarbonate diol as measured by a differential operating calorimeter is −30° C. or less and the average carbon number of a dihydroxy compound obtained by hydrolyzing said polycarbonate diol is from 3 to 5.5.
1. A polycarbonate diol having a hydroxyl value of 20 to 42 mg-KOH/g, wherein:
the glass transition temperature of said polycarbonate diol as measured by a differential scanning calorimeter is −30° C. or less;
an average carbon number of all dihydroxy compounds obtained by hydrolyzing said polycarbonate diol is from 3 to 5.5;
the polycarbonate diol does not contain a structural unit derived from 1,6-hexanediol; and
a ratio of weight average molecular weight/number average molecular weight (Mw/Mn) of said polycarbonate diol ranges from 1.5 to 3.0.
2. The polycarbonate diol as claimed in claim 1 , wherein said dihydroxy compounds consist of an aliphatic dihydroxy compound having no substituent.
3. The polycarbonate diol as claimed in claim 1 , wherein said dihydroxy compounds comprise at least one selected from the group consisting of 1,3-propanediol, 1,4-butanediol and 1,5-pentanediol.
4. The polycarbonate diol as claimed in claim 1 , wherein the melting heat quantity of the polycarbonate diol at a melting peak measured by a differential scanning calorimeter is from 5.0 to 80 J/g.
5. The polycarbonate diol as claimed in claim 1 , wherein said dihydroxy compounds comprise a plant-derived compound.
6. A method for producing the polycarbonate diol of claim 1 , the method comprising transesterifying at least one dihydroxy compound having an average carbon number of 3 to 5.5 with a diaryl carbonate in the presence of a transesterification catalyst to produce the polycarbonate diol.
7. The method of claim 6 , wherein the at least one dihydroxy compound comprises a plant-derived compound.
8. The method of claim 6 , wherein said transesterification catalyst is a compound comprising at least one element selected from the group consisting of a Group 1 element in the long-period periodic table (excluding hydrogen) and a Group 2 element in the long-period periodic table.
9. A polyurethane, comprising the polycarbonate diol of claim 1 .
10. The polycarbonate diol according to claim 1 , comprising a structural unit derived from a compound represented by formula (A) and a structural unit derived from a compound represented by formula (B):
HO—R 1 —OH (A)
HO—R 2 —OH (B)
wherein:
R 1 represents a divalent alkylene group comprising a main chain having a carbon number of 3 to 5; and
R 2 represents a divalent alkylene group comprising a main chain having a carbon number of 8 to 20.
11. The polycarbonate diol according to claim 1 , wherein the average carbon number of the dihydroxy compounds obtained by the hydrolyzing of the polycarbonate diol is from 4.3 to 5.5.
12. The polycarbonate diol according to claim 1 , wherein the average carbon number of the dihydroxy compounds obtained by the hydrolyzing of the polycarbonate diol is from 3 to 5.0.
13. The polycarbonate diol according to claim 1 , wherein the ratio of weight average molecular weight/number average molecular weight (Mw/Mn) of said polycarbonate diol ranges from 1.7 to 3.0.