POLYIMIDE-BASED COPOLYMER AND POLYIMIDE-BASED FILM COMPRISING THE SAME

Abstract

The present disclosure relates to a polyimide-based copolymer and a polyimide-based film including the same. The polyimide-based copolymer according to the present disclosure can provide a polyimide-based film exhibiting low absorbency while having excellent heat resistance and mechanical properties.

Claims

1. A polyimide-based copolymer comprising a first repeating unit represented by Chemical Formula 1 and a second repeating unit represented by Chemical Formula 2: ##STR00014## wherein, in Chemical Formula 1, each R.sup.1 is the same as or different from each other in each repeating unit, and each independently comprises a C6 to C30 divalent aromatic organic group containing at least one O linking group, and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; each R.sup.2 is the same as or different from each other in each repeating unit, and each is independently H, F, Cl, Br, I, CF.sub.3, CCl.sub.3, CBr.sub.3, Cl.sub.3, NO.sub.2, CN, COCH.sub.3, CO.sub.2C.sub.2H.sub.5, a silyl group containing three C1 to C10 aliphatic organic groups, a C1 to C10 aliphatic organic group, or a C6 to C20 aromatic organic group; n1 and m1 are each independently an integer of 0 to 3; each Y.sup.1 is the same as or different from each other in each repeating unit, and each is independently a C3 to C10 aliphatic organic group; and each E.sup.1 is independently a single bond or NH, ##STR00015## wherein, in Chemical Formula 2, each Y.sup.2 is the same as or different from each other in each repeating unit, and each is independently a C6 to C30 divalent aromatic organic group containing at least one trifluoromethyl group (CF.sub.3), and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; E.sup.2, E.sup.3, and E.sup.4 are independently a single bond or NH; and each Y.sup.3 is the same as or different from each other in each repeating unit, and each is independently a divalent linking group derived from at least one compound selected from the group consisting of diacyl halide, dicarboxylic acid, and dicarboxylate in the form of C(O)-A-C(O), wherein A of Y.sup.3 is a C6 to C20 divalent aromatic organic group, a C4 to C20 divalent heteroaromatic organic group, or a C6 to C20 divalent alicyclic organic group, and two of C(O) are bonded at a para position with respect to A.

2. The polyimide-based copolymer of claim 1, wherein the first repeating unit comprises a repeating unit represented by Chemical Formula 1-1: ##STR00016## wherein, in Chemical Formula 1-1, R.sup.2, n1, and m1 are as defined in Chemical Formula 1. each R.sup.3 is the same as or different from each other in each repeating unit, and each is independently a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; and p1 is an integer of 3 to 10.

3. The polyimide-based copolymer of claim 1, wherein the second repeating unit comprises a repeating unit represented by Chemical Formula 2-1: ##STR00017## wherein, in Chemical Formula 2-1, each R.sup.4 is the same as or different from each other in each repeating unit, and each is independently a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; each R.sup.5 is independently H, F, Cl, Br, I, CF.sub.3, CCl.sub.3, CBr.sub.3, Cl.sub.3, NO.sub.2, CN, COCH.sub.3, CO.sub.2C.sub.2H.sub.5, a silyl group containing three C1 to C10 aliphatic organic groups, a C1 to C10 aliphatic organic group, or a C6 to C20 aromatic organic group; n2 and m2 are independently an integer of 0 to 5; E.sup.2, E.sup.3, and E.sup.4 are independently a single bond or NH; and each Y.sup.3 is the same as or different from each other in each repeating unit, and each is independently selected from the group consisting of the following structural formulae: ##STR00018##

4. The polyimide-based copolymer of claim 1, wherein a mole ratio of the first repeating unit to the second repeating unit is 1:0.5 to 2.

5. The polyimide-based copolymer of claim 1, further comprising a third repeating unit represented by Chemical Formula 3: ##STR00019## wherein, in Chemical Formula 3, each R.sup.6 is the same as or different from each other in each repeating unit, and each independently comprises a C6 to C30 divalent aromatic organic group containing at least one O linking group, and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; each R.sup.7 is the same as or different from each other in each repeating unit, and each is independently H, F, Cl, Br, I, CF.sub.3, CCl.sub.3, CBr.sub.3, Cl.sub.3, NO.sub.2, CN, COCH.sub.3, CO.sub.2C.sub.2H.sub.5, a silyl group containing three C1 to C10 aliphatic organic groups, a C1 to C10 aliphatic organic group, or a C6 to C20 aromatic organic group; n3 and m3 are each independently an integer of 0 to 3; each Y.sup.4 is the same as or different from each other in each repeating unit, and each is independently a C6 to C30 divalent aromatic organic group containing at least one trifluoromethyl group (CF.sub.3), and the aromatic organic group exists alone, or two or more aromatic organic groups are bonded to each other to form a condensed ring, or two or more aromatic organic groups are linked by a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH; and each E.sup.5 is independently a single bond or NH.

6. The polyimide-based copolymer of claim 5, wherein the third repeating unit comprises a repeating unit represented by Chemical Formula 3-1: ##STR00020## wherein, in Chemical Formula 3-1, R.sup.7, n3, and m3 are as defined in Chemical Formula 3, and each R.sup.6 is the same as or different from each other in each repeating unit, and each is independently a single bond, a fluorenylene group, O, S, C(O), CH(OH), S(O).sub.2, Si(CH.sub.3).sub.2, (CH.sub.2).sub.p (wherein 1p10), (CF.sub.2).sub.q (wherein 1q10), C(CH.sub.3).sub.2, C(CF.sub.3).sub.2, or C(O)NH.

7. The polyimide-based copolymer of claim 5, wherein a mole ratio of the first repeating unit to the second repeating unit to the third repeating unit is 1:1:0.5 to 2:1 to 3.

8. The polyimide-based copolymer of claim 1, wherein a weight average molecular weight is 90,000 to 150,000 g/mol.

9. A polyimide-based film comprising the polyimide-based copolymer of claim 1.

10. The polyimide-based film of claim 9, which has a water absorbency rate of 0.5 to 2.0%, measured by a change in weight after storage for 15 hours0.5 hours under the conditions of RH 85%2% and 85 C.2 C.

11. The polyimide-based film of claim 9, wherein a glass transition temperature (Tg) is 180 C. to 220 C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] FIG. 1 shows H-NMR data of the polyimide-based copolymer according to Preparation Example 1.

[0087] FIG. 2 is a graph showing a glass transition temperature of the polyimide-based copolymer according to Example 1 and Comparative Example 1.

[0088] FIG. 3 is a graph showing a water absorbency rate of the polyimide-based copolymer according to Example 1 and Comparative Example 1.

DETAILED DESCRIPTION

[0089] Hereinafter, preferred examples are provided for better understanding. However, these examples are for illustrative purposes only, and the invention is not intended to be limited by these examples.

[PREPARATION EXAMPLES]PREPARATION OF A POLYIMIDE-BASED COPOLYMER

Preparation Example 1

[0090] 6.766 g (2.113 eq., 0.02113 mol) of 2,2-bis(trifluoromethyl)benzidine (TMFB), 15.562 g (2.99 eq., 0.0299 mol) of 4,4-bisphenol dianhydride (BPADA), and 150 ml of N-methylpyrrolidone (NMP) were added to a 500 mL round flask equipped with a Dean-Stark apparatus and a condenser, and the mixture was stirred at room temperature. Thereafter, 1.042 g (0.897 eq., 0.00897 mol) of hexamethylenediamine (HMDA) was dissolved in 16 ml of N-methylpyrrolidone (NMP), followed by slow dripping into the flask. After the addition of hexamethylene diamine (HMDA), the reaction mixture was stirred at room temperature for 4 hours under a nitrogen atmosphere to proceed with the reaction.

[0091] After the reaction, a polyamic acid polymer was formed. Then, the reaction mixture was mixed with 3.170 g (0.99 eq., 0.0099 mol) of 2,2-bis(trifluoromethyl) benzidine, 2.051 g (1.01 eq., 0.010 mol) of terephthaloyl dichloride (TPC) and 36 ml of additional N-methyl pyrrolidone (NMP), followed by stirring in an oil bath at 40 C. for 4 hours to synthesize an amide block polymer.

[0092] After completion of the reaction, 102 ml of chlorobenzene was added thereto, the mixture was heated to 190 C., and an imidization reaction of amic acids was carried out by azeotropic distillation while stirring for about 15 hours.

[0093] After completion of the reaction, the reaction mixture was precipitated in water and ethanol (1:1 (v/v)) to obtain a polyimide-based block copolymer containing the following first repeating unit, second repeating unit, and third repeating unit in a mole ratio of about 1:1.1:2.2 (weight average molecular weight: about 130,000 g/mol). Specific NMR data are shown in FIG. 1.

##STR00010##

[0094] 1H NMR (DMSO-d6, TMS as standard material) (ppm): 10.83 (s), 8.38 (s), 8.17 (s) 8.02 (s), 7.62 (s), 7.58 (m), 7.40 (m), 7.32 (m), 7.21 (s), 7.14 (m), 6.94 (m), 3.48 (s), 1.73 (d), 1.51 (s), 1.23 (s)

Comparative Preparation Example 1

[0095] A polyimide-based polymer containing the following repeating units was used.

##STR00011##

[0096] Manufacturer: Solvay, product name: Torlon, weight average molecular weight: about 139,000 g/mol

Comparative Preparation Example 2: A Case of not Containing an Aliphatic Organic Group

[0097] 12.530 g (3.01 eq., 0.03913 mol) of 2,2-bis(trifluoromethyl)benzidine (TMFB); 20.231 g (2.99 eq., 0.0388 mol) of 4,4-bisphenol dianhydride (BPADA) and 230 ml of N-methylpyrrolidone (NMP) were added to a 500 mL round flask equipped with a Dean-Stark apparatus and a condenser. The reaction mixture was stirred in an oil bath at 40 C. for 4 hours under a nitrogen atmosphere to proceed with the reaction.

[0098] After the reaction, a polyamic acid polymer was formed. Then, the reaction mixture was mixed with 4.121 g (0.99 eq., 0.01287 mol) of 2,2-bis(trifluoromethyl) benzidine (TMFB), 2.666 g (1.01 eq., 0.0131 mol) of terephthaloyl dichloride (TPC), and 48 ml of additional N-methyl pyrrolidone (NMP), followed by stirring in an oil bath at 40 C. for 4 hours to synthesize an amide block polymer.

[0099] After completion of the reaction, 140 ml of chlorobenzene was added thereto, the mixture was heated to 190 C., and an imidization reaction of amic acids was carried out by azeotropic distillation while stirring for about 15 hours.

[0100] After completion of the reaction, the reaction mixture was precipitated in water and ethanol (1:1 (v/v)) to obtain a polyimide-based block copolymer containing an imide block and an amide block in a mole ratio of about 3:1 (weight average molecular weight: about 150,000 g/mol).

##STR00012##

Comparative Preparation Example 3

[0101] 8.796 g (2.113 eq., 0.02746 mol) of 2,2-bis(trifluoromethyl)benzidine (TMFB), 17.267 g (2.99 eq., 0.0387 mol) of 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and 180 ml of N-methylpyrrolidone (NMP) were added to a 500 mL round flask equipped with a Dean-Stark apparatus and a condenser, and the mixture was stirred at room temperature. Thereafter, 1.355 g (0.897 eq., 0.01166 mol) of hexamethylenediamine (HMDA) was dissolved in 20 ml of N-methylpyrrolidone (NMP), followed by slow dripping into the flask. After the addition of hexamethylene diamine (HMDA), the reaction mixture was stirred in an oil bath at 40 C. for 4 hours under a nitrogen atmosphere to proceed with the reaction.

[0102] After the reaction, a polyamic acid polymer was formed. Then, the reaction mixture was mixed with 3.170 g (0.99 eq., 0.0099 mol) of 2,2-bis(trifluoromethyl) benzidine, 2.051 g (1.01 eq., 0.010 mol) of terephthaloyl dichloride (TPC), and 36 ml of additional N-methyl pyrrolidone (NMP), followed by stirring in an oil bath at 40 C. for 4 hours to synthesize an amide block polymer.

[0103] After completion of the reaction, 102 ml of chlorobenzene was added thereto, the mixture was heated to 190 C., and an imidization reaction of amic acids was carried out by azeotropic distillation while stirring for about 15 hours.

[0104] After completion of the reaction, the reaction mixture was precipitated in water and ethanol (1:1 (v/v)) to obtain a polyimide-based block copolymer containing an imide block and an amide block in a mole ratio of about 3:1 (weight average molecular weight: about 140,000 g/mol).

##STR00013##

Example 1

[0105] The polyimide-based copolymer obtained in Preparation Example 1 was dissolved in dimethylacetamide to prepare a polymer solution of about 20 (w/V). The polymer solution was poured on a glass plate, the thickness of the polymer solution was uniformly adjusted using a film applicator, and it was dried in a vacuum oven at 20 C. for 12 hours or more to obtain a polyimide-based film having a thickness of 20 to 30 m.

Comparative Examples 1 to 3

[0106] A film was obtained in the same manner as in Example 1, except that the polyimide-based copolymers obtained in Comparative Preparation Examples 1, 2, and 3 were used in place of the copolymer obtained in Preparation Example 1.

Experimental Example 1

[0107] The following properties were evaluated for the films of Example 1 and Comparative Examples 1 to 3 by the following methods, and the results are shown in Table 1.

[0108] 1) Evaluation of Water Absorbency Rate (%)

[0109] The polyimide-based film was stored for 15 hours in a thermo-hygrostat under the conditions of 85%2% and 85 C.2 C., and then allowed to stand at room temperature to measure a change in weight over time (water absorbency). The results are shown in Table 1 and FIG. 2.

[0110] 2) Evaluation of Glass Transition Temperature (Tg, C.)

[0111] The loss modulus of the polyimide-based film was measured at 330 C. under the conditions of 0.1%0.005% strain, 0.050.0005 force, and 10.01 Hz frequency. The glass transition temperature was measured from a temperature of a peak value of the measured loss modulus, and the results are shown in Table 1 and FIG. 3.

TABLE-US-00001 TABLE 1 Water absorbency Glass Index rate (%) transition temperature ( C.) Ex. 1 (LPT 4-1) 1.26 207 Comp. Ex. 1 (Torlon) 4.01 260 Comp. Ex. 2 1.24 268 Comp. Ex. 3 1.18 255

[0112] Referring to Table 1, FIG. 2, and FIG. 3, it was confirmed that the example of the present disclosure has a remarkably low water absorbency rate compared with Torlon of Comparative Example 1, which is conventionally used, so that excellent mechanical properties can be secured when applied to engineering plastics. In addition, it was confirmed that the example according to the present disclosure has excellent moldability by realizing a low glass transition temperature.

[0113] In addition, since Comparative Examples 2 and 3 have relatively high contents of fluorine, their water absorbency rate was comparable to that of the example, but the glass transition temperature was high and thus the moldability was remarkably low. Therefore, it was confirmed that the comparative examples are not easily applicable to engineering plastics.