RESIN COMPOSITION AND FILM

Abstract

A resin composition contains a polyimide resin and an ester-based resin. The ester-based resin is polycarbonate or polyarylate. The polyimide contains a structural unit represented by general formula (1). In general formula (1), X is a divalent organic group shown in group (I), and Y is a divalent group that contains one or more selected from the group consisting of a fluorine group, a trifluoromethyl group, a sulfonic group, a fluorene structure and an alicyclic structure. Each of R.sup.1 and R.sup.2 is a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluoroalkyl group having 1 to 20 carbon atoms, m is an integer of 1 to 4, and n is an integer of 0 to 4.

##STR00001##

Claims

1. A resin composition comprising: a polyimide resin; and an ester-based resin, wherein: the ester-based resin is a polycarbonate or a polyarylate, the polyimide resin is a polyimide containing a structural unit represented by general formula (1), which is obtainable by a reaction of an acid dianhydride represented by general formula (3) and a diamine represented by general formula (4): ##STR00023##
H.sub.2N—Y—N.sub.2   (4) ##STR00024## wherein a content of a tetracarboxylic acid dianhydride represented by general formula (3) is 30 mol % or more based on a total amount of acid dianhydride components of the polyimide, where X in general formulae (1) and (3) is a divalent organic group selected from group (I) ##STR00025## wherein each of R.sup.1 and R.sup.2 is a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluoroalkyl group having 1 to 20 carbon atoms; m is an integer of 1 to 4; and n is an integer of 0 to 4, Y in general formulae (1) and (4) is a divalent group containing one or more selected from the group consisting of a fluorine group, a trifluoromethyl group, a sulfone group, a fluorene structure and an alicyclic structure.

2. The resin composition according to claim 1, wherein the polyimide resin includes an acid dianhydride of formula (6) at 30 mol % or more based on the total amount of the acid dianhydride components ##STR00026##

3. The resin composition according to claim 1, wherein the polyimide resin is soluble in methylene chloride.

4. The resin composition according to claim 1, wherein the ester-based resin is polycarbonate.

5. The resin composition according to claim 4, wherein the polycarbonate contains a repeating unit of formula (8): ##STR00027##

6. The resin composition according to claim 1, wherein the ester-based resin is polyarylate.

7. The resin composition according to claim 6, wherein the polyarylate contains a repeating unit of formula (10): ##STR00028##

8. The resin composition according to claim 1, containing the polyimide resin and the ester-based resin at a weight ratio of 98:2 to 2:98.

9. The resin composition according to claim 1, wherein the polyimide resin has a solubility parameter of 8.10 to 9.10 (cal/cm.sup.3).sup.1/2.

10. A film comprising the resin composition set forth in claim 1.

11. The film according to claim 10, having a thickness of 5 μm or more and 300 μm or less, a haze of 3.5% or less, an YI of 5.0 or less, a thickness retardation Rth of 3000 nm or less, and a tensile modulus of 3.0 GPa or more.

Description

EXAMPLES

[0093] Hereinafter, one or more embodiments of the present invention will be described in further detail on the basis of examples and comparative examples. One or more embodiments of the present invention are not limited to examples below.

Polyimide Resin Production Examples

[0094] Dimethylformamide was added into a separable flask, and stirred in a nitrogen atmosphere. To this was added a diamine and an acid dianhydride at a ratio (%) as shown in Table 2, and the mixture was reacted by stirring in a nitrogen atmosphere for 5 to 10 hours to obtain a polyamic acid solution having a solid content concentration of 18 wt %. In Production Examples 1A to 1C, Production Examples 3A and 3B, Production Examples 4A and 4B, Production Examples 6A and 6B and Production Examples 11A and 11B, the molecular weight was adjusted by changing the reaction time.

[0095] To 100 g of the polyamic acid solution, 5.5 g of pyridine as an imidization catalyst was added, and completely dispersed, 8 g of acetic anhydride was then added, and the mixture was stirred at 90° C. for 3 hours. The solution was cooled to room temperature, and 100 g of 2-propyl alcohol (hereinafter, referred to as “IPA”) was then added dropwise at a rate of 2 to 3 drops/sec while the solution was stirred, thereby precipitating a polyimide. Further, 150 g of IPA was added, the mixture was stirred for about 30 minutes, and suction filtration was performed with a Kiriyama funnel. The obtained solid was washed with IPA, and then dried in a vacuum oven set at 120° C. for 12 hours to obtain a polyimide resin.

Film Production Examples

Films 1 to 14

[0096] The polyimide (PI) obtained in the production example above and a commercially available polyarylate (PAR) were mixed with methylene chloride at a ratio as shown in Table 3, thereby preparing a methylene chloride solution having a resin content of 11 wt %. This solution was applied onto an alkali-free glass plate, and dried by heating at 40° C. for 60 minutes, 70° C. for 30 minutes, 150° C. for 30 minutes, 170° C. for 30 minutes and 200° C. for 60 minutes in an air atmosphere to produce Films 1 to 14 having a thickness of about 50 μm.

Films 21 to 28

[0097] The polyimide (PI) obtained in the production example above and a commercially available polycarbonate (PC) were mixed with methylene chloride at a ratio as shown in Table 4, thereby preparing a methylene chloride solution having a resin content of 11 wt %. This solution was applied and dried under the same conditions as in the preparation of Films 1 to 14 described above, thereby producing Films 21 to 28 having a thickness of about 50 μm.

Reference Examples A to D

[0098] In Reference Examples A and C, a methylene chloride solution of a polyimide resin was prepared, and a film having a thickness of about 50 μm was produced under the same conditions as described above. In Reference Example B, a methylene chloride solution of a polyarylate was prepared, and a film having a thickness of about 50 μm was produced under the same conditions as described above. In Reference Example D, a methylene chloride solution of polycarbonate was prepared, and applied and dried under the same conditions as described above, thereby producing a film having a thickness of about 50 μm.

Evaluation Methods

Evaluation of Polyimide Resin

Solubility in Methylene Chloride

[0099] To the polyimide resin was added methylene chloride to a solid content concentration of 10 wt %, and the mixture was stirred at room temperature for 12 hours, followed by visual examination of the solution. The polyimide resins of all production examples were free of an insoluble substance, and had solubility in methylene chloride.

Molecular Weight

[0100] The polyimide was dissolved in the eluent to have a concentration of 0.04 wt %, and analysis with GPC was performed under the conditions shown in Table 1 to obtain weight average molecular weight (Mw).

TABLE-US-00001 TABLE 1 Item Condition Apparatus Column oven: CO-8020 Degasser: SD-8022 Pump: DP-8020 Detector: RI-8020 Auto sampler: AS-8020 (each manufactured by Tosho Corporation) Column Shodex GPC KD-806M × 2, each having 8 mmφ × 30 cm, total 60 cm uard column Shodex GPC KD-G, 4.6 mmφ × 1 cm Column temperature 40° C. Eluent 30 mM-LiBr + 30 mM-phosphoric acid/DMF Flow rate: 0.6 mL/min Injection pressure About 1.3 to 1.7 MPa Injection volume 30 μL (solid content concentration of 0.4 wt %) Standard sample Polyethylene oxide (used for preparation of calibration curve) Detector RI Order of calibration curve One dimension

Evaluation of Film

Haze

[0101] The film was cut to a 3 cm square, and measured in accordance with JIS K 7136 using a haze meter “HZ-V3” manufactured by Suga Test Instruments Co., Ltd. For those having a haze of more than 20%, measurements of the yellowness index, the tensile modulus and the thickness-direction retardation below were not performed (indicated as ND in Tables 3 and 4).

Yellowness Index

[0102] The film was cut to a 3 cm square, and the yellowness index (YI) was measured in accordance with JIS K 7373 using a spectrophotometer “SC-P” manufactured by Suga Test Instruments Co., Ltd.

Tensile Modulus

[0103] The film was cut into a strip shape having a width of 10 mm, and the tensile modulus was measured using “AUTOGRAPH AGS-X” manufactured by Shimadzu Corporation under the following conditions: distance between grippers: 100 mm, and tensile speed: 20.0 mm/min.

Thickness-Direction Retardation

[0104] The film was cut to a 3 cm square, and the in-plane retardation and the oblique direction retardation at a wavelength of 590 nm were measured using a retardation measuring apparatus “KOBRA” manufactured by Oji Scientific Instruments, and the thickness-direction retardation Rth was calculated with an average refractive index of 1.60.

Evaluation Results

[0105] Table 2 shows the compositions of the diamine and the acid dianhydride and the SP value and the weight average molecular weight (Mw) of the polyimide in the production examples of the polyimide. The unit of the SP value in Table 2 is (cal/cm.sup.3).sup.1/2, and the SP value of the polyimide is a value obtained by adding the products of the SP values of the monomers and the molar ratios to the total amount of the diamine and the acid dianhydride.

[0106] In Table 2, the compounds are represented by the following abbreviations.

Diamine

[0107] TFMB: 2,2′-bis(trifluoromethyl)benzidine

[0108] 3,3′-DDS: 3,3′-diaminodiphenylsulfone

Acid Dianhydride

[0109] TAHMBP: bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-2,2′,3,3′,5,5′-hexamethylbiphenyl-4,4′-diyl

[0110] OCBP-TME: bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)-3,3′-dimethylbiphenyl-4,4′-diyl

[0111] BP-TME: bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)biphenyl-4,4′-diyl

[0112] Bis-DA2000: 4,4′-(4,4′-isopropylidenediphenoxy)diphthalic dianhydride

[0113] TMEIQ: p-phenylene bis(trimellitic acid monoester acid anhydride)

[0114] s-BPDA: 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride

[0115] α-BPDA: diphenyl-2,3,3′,4′-tetracarboxylic dianhydride

[0116] CBDA: 1,2,3,4-cydobutanetetracarboxylic acid dianhydride

[0117] 6FDA: 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride

TABLE-US-00002 TABLE 2 Composition (mol %) Pro- Diamine Acid dianhydride duction Mono- 3, 3′- TAH OCBP- BP- Bis- Ex- mer TFMB DDS MBP TME TME DA2000 TMHQ s-BPDA α-BPDA CBDA 6FDA Polyimide ample SP 7.96 10.22 8.14 8.74 8.93 8.10 9.56 10.83 10.79 13.33 8.21 SP Mw 1A 90 10 50 — — — — 15 — 15 20 8.76 69500 1B 110000 1C 140000 2 90 10 45 — — — — — 10 25 20 8.95 58000 3A 90 10 50 — — 15 — — — 15 20 8.56 96900 3B 146000 4A 90 10 50 — — 15 — 15 — — 20 8.37 82300 4B 105000 5 90 10 50 — — 30 — — — — 20 8.16 121000 6A 90 10 50 — — 20 0 15 — 15 — 8.75 86000 6B 101000 7 90 10 40 — 10 0 0 15 — 15 20 8.80 103000 8 90 10 40 10 — — — 15 — 15 20 8.79 116000 9 90 10 40 — — — — — — — 60 8.18 80100 10  90 10 70 — — — — — — — 30 8.17 150000 11A  70 30 — — — — 25 25 — — 50 8.92 87500 11B  99500 12  100  — — — — — — — — 40 60 9.11 95600 13  100  — — — — — — — — — 100  8.09 88500

[0118] Table 3 shows the resin compositions and film characteristics of Films 1 to 14 (compositions of polyimides and polyarylates) produced in the film production examples, and Table 4 shows the resin compositions and film characteristics of the Films 21 to 28 (compositions of polyimides and polycarbonate). Table 3 also shows the results of Reference Examples A and B, and Table 4 also shows the results of Reference Examples C and D.

[0119] Among the acid dianhydride components of the polyimide (PI), those corresponding to the polyimide of general formula (3) are selected, and shown in Tables 3 and 4. The number given in parentheses is the ratio (mol %) of the relevant acid dianhydride to the total amount of acid dianhydride components.

[0120] The polyarylates (PAR) in Table 3 and the polycarbonate (PC) in Table 4 are as follows. Mw is a weight average molecular weight in terms of polystyrene which is measured by GPC.

[0121] PAR1: “U-100 D Series” (Mw=71,000) manufactured by UNITIKA LTD.

[0122] PAR2: “U-100 L Series” (Mw=45,600) manufactured by UNITIKA LTD.

[0123] PC1: “Iupilon K 4100” (Mw=38,400) manufactured by Mitsubishi Engineering-Plastics Corporation

[0124] PC2: “Panlite L-1225 LM” (Mw=42,000) manufactured by Teij in Ltd.

TABLE-US-00003 TABLE 3 PI Film properties Acid PI/PAR Tensile dianhydride of PAR (weight Haze modulus Rth Film formula (3) Mw Mw ratio) (%) YI (GPa) (nm) 1 1A TAHMBP(50) 69500 PAR1 71000 80/20 0.32 2.3 4.4 2870 2 1B TAHMBP(50) 110000 PAR1 71000 50/50 0.35 1.6 3.4 1958 3 10 TAHMBP(50) 140000 PAR1 71000 50/50 0.34 1.6 3.4 1960 4 2 TAHMBP(45) 58000 PAR2 45600 80/20 1.40 2.1 3.1 2760 5  3A TAHMBP(50) 96900 PAR1 71000 50/50 0.45 1.6 3.2 2161 Bis-DA2000(15) 6  4A TAHMBP(50) 82300 PAR1 71000 50/50 0.60 1.6 3.1 1814 Bis-DA2000(15) 7  6A TAHMBP(50) 86000 PAR1 71000 50/50 0.50 1.5 3.1 1650 Bis-DA2000(20) 8 7 TAHMBP(40) 103000 PAR2 45600 80/20 3.14 4.6 3.3 2912 BP-TME(10) 9 8 TAHMBP(40) 116000 PAR2 45600 80/20 3.34 5.0 3.5 2850 OCBP-TME(10) 10 9 TAHMBP(40) 80100 PAR2 45600 80/20 3.35 2.4 4.1 2601 11 11A — 87500 PAR2 45600 80/20 41.2 ND ND ND 12 12 — 95600 PAR2 45600 80/20 40.0 ND ND ND 13 13 — 88500 PAR2 45600 80/20 40.5 ND ND ND 14 13 — 88500 PAR2 45600 50/50 78.8 ND ND ND Reference  1A TAHMBP(50) 69500 100/0   0.40 2.6 5.0 3900 Example A Reference — PAR1 71000   0/100 0.62 0.9 1.9  600 Example B

TABLE-US-00004 TABLE 4 PI Film properties Acid PI/PC Tensile dianhydride PC (weight Haze modulus Rth Film of formula (3) Mw Mw ratio) (%) YI (GPa) (nm) 21 10 TAHMBP(70) 150000 PC1 38400 80/20 0.54 1.7 4.4 2400 22  3B TAHMBP(50) 146000 PC2 42000 80/20 5.56 3.9 4.6 2532 Bis-DA2000(15) 23  4B TAHMBP(50) 105000 PC2 42000 80/20 17.8 4.4 4.7 2467 Bis-DA2000(15) 24  5 TAHMBP(50) 121000 PC2 42000 80/20 4.78 3.7 4.4 2350 Bis-DA2000(30) 25  6B TAHMBP(50) 101000 PC2 42000 80/20 36.8 ND ND ND Bis-DA2000(20) 26 12 — 95600 PC1 38400 50/50 50.2 ND ND ND 27 13 — 88500 PC1 38400 50/50 48.2 ND ND ND 28 11B — 99550 PC2 42000 80/20 41.5 ND ND ND Reference 10 TAHMBP(70) 150000 — — 100/0   0.40 2.6 5.0 3250 Example C Reference — PC1 38400   0/100 0.62 0.9 2.1 47 Example D

[0125] The polyimide film of Reference Example A produced using only polyimide 1A and the polyimide film of Reference Example B produced using only polyimide 10 had a small haze, excellent transparency and a high tensile modulus, but had a large Rth. The polyarylate film of Reference Example B prepared using only a polyarylate and the polycarbonate film of Reference Example D prepared using only polycarbonate had excellent transparency and a small Rth, but had a tensile modulus of about 2 GPa, and were not sufficient in mechanical strength.

[0126] As shown in Table 3, the Films 1 to 10, which were prepared with using a composition of a polyarylate and a polyimide containing a bis(trimellitic anhydride) ester of general formula (3) such as TAHMBP as an acid dianhydride component, exhibited high transparency, and tensile modulus and Rth values intermediate between the polyimide and the polyarylate.

[0127] Comparison of the Film 1 with the Film 2 shows that the tensile modulus tends to increase as the ratio of the polyimide becomes higher, and the Rth tends to decrease as the ratio of the polyarylate becomes higher. From the comparison of the Film 2 with the Film 3, it is considered that the difference in molecular weight of the polyimide does not have a significant effect on the haze, the tensile modulus and the Rth.

[0128] The Films 11 to 14, which were prepared with using a composition of a polyarylate and a polyimide free of a bis(trimellitic anhydride) ester of general formula (3) as an acid dianhydride component, exhibited a high haze and was poor in usefulness for optics applications. Since a transparent film is obtained from each of the polyimide resins and polyarylates used for producing these films, poor compatibility of resins may be a cause of cloudiness.

[0129] These results show that the polyarylate and the polyimide containing the bis(trimellitic anhydride) ester of general formula (3) are compatible with each other, so that it is possible to produce a film having high transparency, and by adjusting the mixing ratio of the former to the latter, a film having both a high tensile modulus and a low Rth can be produced.

[0130] The Film 4 in which the polyimide 2 having TAHMBP in an amount of 45 mol % based on the total amount of acid dianhydrides and were mixed at a weight ratio of 80:20 maintained transparency, but had a haze higher than that of the Film 1. The Film 10 in which the polyimide 9 having TAHMBP in an amount of 40 mol % based on the total amount of acid dianhydrides and a polyarylate were mixed at a weight ratio of 80:20 had a further high haze. These results show that the higher the ratio of TAHMBP in the acid dianhydride component of the polyimide, the better the compatibility with the polyarylate.

[0131] The Film 5 in which the polyimide 3A containing, as acid anhydrides, TAHMBP at 50 mol % and Bis-DA 2000 that is an ester of bisphenol A and trimellitic anhydride were mixed with a polyarylate had a haze as low as that of each of the Films 1 to 3. The same applies to the Films 6 and 7.

[0132] The Film 8 in which the polyimide 7 containing, as acid anhydrides, TAHMBP at 40 mol % and BP-TME that is an ester of biphenol and trimellitic anhydride were mixed with a polyarylate had a haze of about 3% like the Film 10. The same applies to the Film 9 prepared using the polyimide 8 containing OCBP-TME as an acid dianhydride component.

[0133] The above results show that, among the compounds of general formula (3), TAHMBP containing a biphenyl backbone having three substituents on each benzene ring makes a particularly large contribution to improvement of compatibility with a polyarylate.

[0134] As shown in Table 4, the Film 21, which was prepared with using a composition of polycarbonate and a polyimide containing a bis(trimellitic anhydride) ester of general formula (3) such as TAHMBP as an acid dianhydride component, exhibited high transparency, and tensile modulus and Rth values intermediate between the polyimide and the polycarbonate.

[0135] The Films 26 to 28, which were prepared with using a composition of polycarbonate and a polyimide free of a bis(trimellitic anhydride) ester of general formula (3) as an acid dianhydride component, exhibited a high haze and was poor in usefulness for optics applications. Since a transparent film was obtained from each of the polyimide resins and polycarbonate used for producing these films, poor compatibility of resins may be a cause of cloudiness.

[0136] The Films 22 to 25, which were prepared with using a composition of polycarbonate and a polyimide containing TAHMBP at 50 mol % and Bis-DA 2000 had a lower haze as compared to the Films 26 to 28, but had a higher haze as compared to the Film 21. These results show that TAHMBP as an acid dianhydride of the polyimide also made a large contribution to improvement of compatibility when the polyimide was mixed with polycarbonate.

[0137] Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the invention should be limited only by the attached claims.