Polyimide precursor composition, polyimide film, and transparent flexible film

A polyimide precursor composition comprising a polyimide precursor having a structure represented by the following general formula (III),

• NH—X—NH—CO—Y(COOR)2—COm (III)
• wherein in the formula (III), m is a natural number representing the number of repetitions of the structural unit, each of m X's is independently a divalent organic group, and the polyimide precursor comprises, as X's, both a group represented by the following general formula (IV),
• and a trans-1,4-cyclohexylene group, wherein R1 and R2 in the formula (IV) are each independently one selected from —H, —(CF2)n—CF3, and —O(CF2)n—CF3, wherein n is an integer of 0 or more and 7 or less, and at least one of R1 and R2 is a fluorine-containing group, and in the formula (III), each of m Y's is independently a tetravalent organic group, and the polyimide precursor comprises as Y's both an aliphatic group and an aromatic group, and each of 2m R's is independently a hydrogen atom or a monovalent organic group, and wherein —CO—Y(COOR)2—CO— in formula (III) is derived from a mixture of 3,3′,4,4′-bicyclohexyl tetracarboxylic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride.

A polyimide film comprising a heat cured polyimide precursor composition, wherein the polyimide precursor composition comprises a polyimide precursor having a structure formed by reacting (i) a diamine component (A), including a fluorine-containing aromatic diamine (a1) represented by the following chemical formula (I),

• wherein in the formula (I), R1 and R2 are each independently selected from —H, —(CF2)n—CF3, and —O(CF2)n—CF3, wherein n is an integer of 0 or more and 7 or less, and at least one of R1 and R2 is a fluorine-containing group, and trans-1,4-cyclohexyldiamine (a2), with (ii) an acid dianhydride component (B) including an aliphatic tetracarboxylic dianhydride (b1) and an aromatic tetracarboxylic dianhydride (b2), wherein the aliphatic tetracarboxylic dianhydride (b1) is 3,3′,4,4′-bicyclohexyl tetracarboxylic dianhydride, and the aromatic tetracarboxylic acid dianhydride (b2) is 3,3′,4,4′-biphenyltetracarboxylic dianhydride, wherein the diamine component (A) includes the trans-1,4-cyclohexyldiamine (a2) in an amount of 50 mol % or more and 95 mol % or less, and
• wherein the polyimide film has a transmittance of 400 nm light of 80% or more at a film thickness of 10 μm, a thermal expansion coefficient of 20 ppm/° C. or less in the range of 100° C. to 200° C., and a glass transition temperature of 250° C. or more.

A polyimide precursor composition comprising a polyimide precursor having a structure formed by reacting (i) a diamine component (A), including a fluorine-containing aromatic diamine (a1) represented by the following chemical formula (I),

• wherein in the formula (I), R1 and R2 are each independently selected from —H, —(CF2)n—CF3, and —O(CF2)n—CF3, wherein n is an integer of 0 or more and 7 or less, and at least one of R1 and R2 is a fluorine-containing group, and trans-1,4-cyclohexyldiamine (a2), with (ii) an acid dianhydride component (B) including an aliphatic tetracarboxylic dianhydride (b1) and an aromatic tetracarboxylic dianhydride (b2), and
• wherein the diamine component (A) includes the trans-1,4-cyclohexyldiamine (a2) in an amount of more than 50 mol % and 95 mol % or less.

A polyimide film comprising a heat cured polyimide precursor composition, wherein the polyimide precursor composition comprises a polyimide precursor having a structure formed by reacting (i) a diamine component (A), including a fluorine-containing aromatic diamine (a1) represented by the following chemical formula (I),

• wherein in the formula (I), R1 and R2 are each independently selected from —H, —(CF2)n—CF3, and —O(CF2)n—CF3, wherein n is an integer of 0 or more and 7 or less, and at least one of R1 and R2 is a fluorine-containing group, and trans-1,4-cyclohexyldiamine (a2), with (ii) an acid dianhydride component (B) including an aliphatic tetracarboxylic dianhydride (b1) and an aromatic tetracarboxylic dianhydride (b2), wherein the aliphatic tetracarboxylic dianhydride (b1) is 3,3′,4,4′-bicyclohexyl tetracarboxylic dianhydride, and the aromatic tetracarboxylic acid dianhydride (b2) is 3,3′,4,4′-biphenyltetracarboxylic dianhydride, wherein the diamine component (A) includes the trans-1,4-cyclohexyldiamine (a2) in an amount of more than 50 mol % and 95 mol % or less, and
• wherein the polyimide film has a transmittance of 400 nm light of 80% or more at a film thickness of 10 μm, a thermal expansion coefficient of 20 ppm/° C. or less in the range of 100° C. to 200° C., and a glass transition temperature of 250° C. or more.