Polyimide precursor and polyimide
A polyimide precursor including at least one repeating unit represented by the following chemical formula (1): in which A is an arylene group; and X 1 and X 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, and a polyimide obtained from the polyimide precursor has a coefficient of linear thermal expansion from 50° C. to 400° C. of 100 ppm/K or less.
1. A silica-containing polyimide, comprising:
silica particles, and
a polyimide comprising at least one repeating unit represented by the following chemical formula (5):
wherein A is an arylene group, and the polyimide comprises at least a repeating unit of the chemical formula (5) in which A is a group represented by the following chemical formula (3-1) or (3-2):
and wherein the polyimide has a coefficient of linear thermal expansion from 50° C. to 400° C. of 100 ppm/K or less, and
wherein an amount of the silica particles is 5 to 16 vol % based on the volume of the polyimide.
2. The silica-containing polyimide according to claim 1 , wherein the polyimide has a light transmittance at 400 nm of 72% or more in the form of a film having a thickness of 10 μm.
3. The silica-containing polyimide according to claim 1 , wherein the polyimide has a light transmittance at 400 nm of more than 75% in the form of a film having a thickness of 10 μm.
4. A substrate for a display, a touch panel or a solar battery formed from the silica-containing polyimide according to claim 1 .
5. A varnish, comprising:
silica particles, and
a polyimide precursor comprising at least one repeating unit represented by the following chemical formula (1):
wherein A is an arylene group; and X 1 and X 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms, and the polyimide comprises at least a repeating unit of the chemical formula (1) in which A is a group represented by the following chemical formula (3-1) or (3-2):
wherein a polyimide obtained from the polyimide precursor has a coefficient of linear thermal expansion from 50° C. to 400° C. of 100 ppm/K or less, and
wherein an amount of the silica particles is 5 to 16 vol % based on a volume of polyimide obtainable from the polyimide precursor.
6. A silica-containing polyimide film obtained using the varnish according to claim 5 .
7. A varnish, comprising:
silica particles; and
a polyimide comprising at least one repeating unit represented by the following chemical formula (5):
wherein A is an arylene group, and the polyimide comprises at least a repeating unit of the chemical formula (5) in which A is a group represented by the following chemical formula (3-1) or (3-2):
and wherein the polyimide has a coefficient of linear thermal expansion from 50° C. to 400° C. of 100 ppm/K or less, and
wherein an amount of the silica particles is 5 to 16 vol % based on a volume of the polyimide.
8. A silica-containing polyimide film obtained using the varnish according to claim 7 .