JP2022010372A - Method for producing polyamic acid, polyamic acid, polyimide resin, and polyimide film produced from this. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyamic acid having an improved coefficient of linear thermal expansion while maintaining optical characteristics, a polyamic acid produced from the method, a polyimide resin and a polyimide film, and an image display element including the same.
SOLUTION: A diamine containing TFDB (2,2'-bis (trifluoromethyl) benzidine) and an acid dianhydride containing PMDA (1,2,4,5-benzene tetracarboxylic dianhydride) are added and reacted. One step is carried out, followed by a second step in which a diamine containing TFDB and an acid dianhydride containing 6FDA (2,2-Bis (4-carboxyphenyl) hexafluoropropane dianhydride) are added and reacted. Here, the molar ratio of <PMDA> to <6FDA> is 90 to 70:10 to 30.
[Selection diagram] None

Description

The present invention relates to a method for producing a polyamic acid, a polyamic acid produced from the method, a polyimide resin, and a polyimide film.

Generally, a polyimide (PI) film is a film made of a polyimide resin.
The polyimide resin is a highly heat-resistant resin produced by solution-polymerizing an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate to produce a polyamic acid derivative, and then subjecting it to ring-sealing dehydration at a high temperature to imidize it. To tell.

Since such a polyimide film has excellent mechanical, heat-resistant, and electrically insulating properties, it has a wide range of electronic materials such as semiconductor insulating films, TFT-LCD electrode protective films, and flexible printed substrates. It is used in various fields.

However, since the polyimide resin is colored brown and yellow due to its high aromatic ring density, it has low transmittance in the visible light region, exhibits a yellowish series color, and has low light transmittance, and is high. Since it has a birefringence index, it is difficult to use it as an optical member.

US Pat.
No. 7, No. 5367046, No. 5338826, No. 5986036, No. 62
In 32428 and Korean Patent Publication No. 2003-0009437, -O-, -SO
Aromatic dianhydrides that are a monomer with a bent structure linked to a linking group such as 2-, CH2-, and an m-position other than the p-position, or an aromatic dianhydride having a substituent such as -CF3, and aromatics. It has been reported that the use of diamine monomers produced a polyimide with a new structure in which the transmittance and the transparency of the hue were improved within the limit that the thermal properties did not deteriorate significantly. In terms of compound refraction, the results were insufficient to be used as a material for display elements such as OLEDs, TFT-LCDs, and flexible displays.

An object of the present invention is a method for producing a polyamic acid, which maintains the same raw material and usage amount of the existing composition, but improves the linear thermal expansion coefficient while maintaining the optical characteristics by changing the charging method.
It is an object of the present invention to provide a polyamic acid, a polyimide resin and a polyimide film produced from this, and an image display element containing the same.

A preferred embodiment of the present invention is bistrifluoromethylbenzidine (2,2'-bis (2,2'-bis).
With diamines containing trifluoromethyl) benzidine, TFDB),
Pyromeric acid dianhydride (1,2,4,5-benzene terracarboxyl)
The step of adding an acid dianhydride containing ic dianhydride (PMDA) and bistrifluoromethylbenzidine (2,2'-bis (trifluoromethyl)).
Diamine containing benzidine, TFDB) and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic). d
Provided is a method for producing a polyamic acid, which comprises a step of adding an acid dianhydride containing one or more selected from ianhydride (BPDA).

The molar ratio of <PMDA> to <one or more selected from 6FDA and BPDA> is
It is characterized by being 90 to 25:10 to 75.

The molar ratio of <PMDA> to <6FDA> is 90 to 70:10 to 30.

The molar ratio of <PMDA> to <BPDA> is 90 to 25:10 to 75.

The molar ratio of <PMDA> to <6FDA> to <BPDA> is 90 to 50: 5 to 30.
: It is characterized by being 5 to 20.

The diamine is bisaminophenylfluorene (9,9-Bis (4-ami).
nophenyl) fluoride, FDA) and bisfluoroaminophenylfluorene (9,9-Bis (3-fluoro-4-aminophenyl) fluorore
It is characterized in that one or more kinds selected from (ne, FFDA) are further added.

The bisaminophenylfluorene (9,9-Bis (4-aminophenyl)
Fluorene (FDA) and bisfluoroaminophenylfluorene (9,9-Bi)
One or more selected from s (3-fluoro-4-aminofluorene, FFDA) is characterized in that it is added in a content of 1 mol% to 20 mol% with respect to the total mole of diamine.

Another preferred embodiment of the invention is bistrifluoromethylbenzidine (2,2'-bi).
Repeating units derived from s (trifluoromethyl) benzidine, TFDB) and pyromeritic acid dianhydride (1,2,4,5-benzene terraca).
A first block structure containing repeating units derived from rboxylic dianhydride, PMDA) and bistrifluoromethylbenzidine (2,2'-bis (tri).
Repeat units derived from fluoromethyl) benzidine, TFDB) and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6).
FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-Biphenyl)
Provided is a polyamic acid comprising a second block structure comprising a repeating unit derived from one or more selected from tetracarboxylic dianhydride, BPDA).

<PMDA in the first block structure> vs. <6FDA in the second block structure
And the molar ratio of one or more selected from BPDA> is 90 to 25:10 to 75.

<PMDA in the first block structure> vs. <6FDA in the second block structure
> The molar ratio is 90 to 70: 10 to 30.

The above-mentioned <PMDA in the first block structure> vs. <BPDA in the second block structure
> The molar ratio is 90 to 25:10 to 75.

<PMDA in the first block structure> vs. <6FDA in the second block structure
> The molar ratio of <BPDA in the second block structure> is 90-50: 5-30: 5-2.
It is characterized by being 0.

The second block structure containing the above <repeating unit derived from TFDB> and <repeating unit derived from one or more selected from 6FDA and BPDA> is bisaminophenylfluorene (9,9-Bis (4). -Aminophenyl) fluorene, FDA
) And bisfluoroaminophenylfluorene (9,9-Bis (3-fluoro-4)
-It is characterized by further containing a repeating unit derived from one or more selected from (aminophenyl) fluorene, FFDA).

The content of the above <one or more selected from FDA and FFDA> is characterized by being 1 mol% to 20 mol% with respect to the total mole of diamine.

Another preferred embodiment of the present invention provides a polyimide resin made from the polyamic acid described above.

Another preferred embodiment of the present invention provides a polyimide film made from the polyimide resin.

The polyimide film has a coefficient of thermal expansion (Coefficient) at 50 to 350 ° C.
Of Thermal Expansion) is 30 ppm / ° C. or less, and when measured with a UV spectrometer, the transmittance at 550 nm is 85% or more and the yellowness is 10 or less.

Another preferred embodiment of the present invention provides an image display device including a polyimide film.

According to the present invention, a method for producing a polyamic acid having an improved linear thermal expansion coefficient while maintaining yellowness and transmittance after the formation of a film or a film, and a polyamic acid, a polyimide resin, and a polyimide film produced from the method are used. Can be provided.

According to one embodiment of the present invention, bistrifluoromethylbenzidine (2,2'-bis (2,2'-bis)
With diamines containing trifluoromethyl) benzidine, TFDB),
Pyromeric acid dianhydride (1,2,4,5-benzene terracarboxyl)
The stage of adding an acid dianhydride containing ic dianhydride (PMDA), and
Bistrifluoromethylbenzidine (2,2'-bis (trifluorometry)
l) Diamine containing benzidine (TFDB), 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4) -Biphenyltellacarboxylic
Provided is a method for producing a polyamic acid, which comprises a step of adding an acid dianhydride containing one or more selected from dianhydride (BPDA).

The present invention has the effect of improving the coefficient of linear thermal expansion while maintaining the optical characteristics at an excellent level by adding one type of diamine once or more under specific conditions, for example, by dividing it into primary and secondary diamines. Can be obtained.

Hereinafter, the present invention will be described in more detail.

In the method for producing a polyamic acid according to an embodiment of the present invention, bistrifluoromethylbenzidine (2,2'-bis (trifluoromethyl) benzidin)
e, TFDB) -containing diamine and pyromeritic acid dianhydride (1,2,4,5-benze)
The step of adding an acid dianhydride containing nettracarboxic dianhydride (PMDA), and bistrifluoromethylbenzidine (2,2'-bi).
Diamine containing s (trifluoromethyl) benzidine, TFDB) and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (
6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-Biphenyl)
It is preferable to carry out the step including a step of secondary addition of an acid dianhydride containing one or more selected from ethyltracarboxic dianhydride (BPDA).

The molar ratio of <PMDA> to <one or more selected from 6FDA and BPDA> is
It is preferably 90 to 25:10 to 75, preferably 90 to 30:10 to 70.

When the above <PMDA> and <one or more selected from 6FDA and BPDA> are out of the range of the molar ratio, there is a problem that they have a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm / ° C or more. possible.

In the present specification, the bistrifluoromethylbenzidine (2,2'-bis (trif).
Diamines containing luminomethyl) benzidine, TFDB) and pyromeritic acid dianhydride (1,2,4,5-benzene terracarboxylic d).
The step of adding the dianhydride containing ianhydride (PMDA) is called the primary addition, and bistrifluoromethylbenzidine (2,2'-bis (trifluor)) is added.
Diamine containing omethyl) benzidine, TFDB) and 2,2-bis (3)
, 4-Dicarboxyphenyl) Hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarb)
The step of adding an acid dianhydride containing one or more selected from oxylic dianhydride (BPDA) can be named secondary addition, but this does not limit the order of addition and divides the injection stage. Just name it for.

Here, 2 from the above <one or more selected from 6FDA and BPDA at the time of secondary injection>
When seeds or more are added, the total mole of acid dianhydride at the time of secondary addition is <1 above.
It means that it is added in comparison with PMDA> at the time of the next input.

In addition, 6F from the above <one or more selected from 6FDA and BPDA at the time of secondary injection>
When DA is selected and charged, the above-mentioned <PMDA at the time of primary charging> vs. <6FD at the time of secondary charging>
The molar ratio of A> is preferably 90 to 70:10 to 30, preferably 90 to 75:10 to 25.

When the <PMDA at the time of primary charging> and <6FDA at the time of secondary charging> are out of the range of the molar ratio, if the ratio of PMDA is higher than this range, the coefficient of linear thermal expansion becomes very low. There may be a problem that the yellowness becomes very high, and if the ratio of 6FDA is higher than this range, there is an advantage that the yellowness becomes very low, but there is a problem that the coefficient of linear thermal expansion increases. possible.

In addition, BP from the above <one or more selected from 6FDA and BPDA at the time of secondary injection>.
When DA is selected and charged, the above-mentioned <PMDA at the time of primary charging> vs. <BPD at the time of secondary charging>
The molar ratio of A> is preferably 90 to 25:10 to 75, preferably 85 to 30:15 to 70.

When the above <PMDA at the time of primary charging> and <BPDA at the time of secondary charging> are out of the range of the molar ratio, if the ratio of PMDA is higher than this range, the coefficient of linear thermal expansion becomes very low. There can be a problem that the yellowness becomes very high, and if the ratio of BPDA is higher than this range, there is an advantage that the yellowness is lower than that of PMDA, but there is a problem that the coefficient of linear thermal expansion increases. possible.

In one embodiment of the present invention, <1 selected from 6FDA and BPDA at the time of secondary injection 1
When two or more seeds are charged from the seeds or more>, the molar ratio of <PMDA at the time of primary charging> to <6FDA at the time of secondary charging> to <BPDA at the time of secondary charging> is 90 to 50: 5. ~ 30: 5 ~ 20
Is more preferable.

When the <PMDA at the time of primary charging> and <6FDA and BPDA at the time of secondary charging> are out of the range of the molar ratio, it is said that they have a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm / ° C. or more. There can be a problem.

In the present invention, the above-mentioned <acid dianhydride containing PMDA> is first added, and then <acid dianhydride containing one or more selected from 6FDA and BPDA> is added.
It is more preferable in that the coefficient of linear thermal expansion and the degree of yellowness can be improved at the same time as compared with the case where the acid dianhydride containing A> is added later.

That is, in one embodiment of the present invention, bistrifluoromethylbenzidine (2,2'-b)
Diamine containing is (trifluoromethyl) benzidine, TFDB) and pyromeritic acid dianhydride (1,2,4,5-benzene terracarbo)
Acid dianhydride containing xylic dianhydride (PMDA) is added first, and bistrifluoromethylbenzidine (2,2'-bis (trifluoromethyl)) is added.
) Benzidine, TFDB) containing diamine, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-) Biphenyltellacarboxylic
It is preferable to add an acid dianhydride containing at least one selected from dianhydride (BPDA) later in that the physical properties of the present invention can be further improved.

In addition, as the diamine at the time of the secondary addition, bisaminophenylfluorene (9,9-
Bis (4-aminophenyl) fluoride, FDA) and bisfluoroaminophenylfluorene (9,9-Bis (3-fluoro-4-aminophen)
One or more selected from yl) fluorene, FFDA) can be further added. When the above <one or more selected from FDA and FFDA> is further added, the effect of improving the glass transition temperature can be obtained.

The above <one or more selected from FDA and FFDA> is preferably contained in a content of 1 mol% to 20 mol%, preferably 1 to 10 mol% with respect to the total mole of diamine. When one or more selected from the FDA and FFDA is out of the above range, if it is less than 1 mol%, the content may be small and there may be almost no effect of improving the glass transition temperature, and 20 mol% may be used. If it exceeds, there may be a problem that the yellowness and the coefficient of thermal expansion decrease.

According to one embodiment of the present invention, after the secondary injection, bistrifluoromethylbenzidine (
2,2'-bis (trifluoromethyl) benzidine, TFDB)
Diamine containing 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-)
Biphenyltracarboxylbic dyandride, BPDA
) Can be carried out including a step of tertiary addition of an acid dianhydride containing one or more selected from).

The diamine and acid dianhydride at the time of the tertiary charging can be appropriately adjusted and added within the range of the molar ratio of the diamine and the dianhydride at the time of the primary charging and the secondary charging described above.

Examples of the diamine used in one embodiment of the present invention include TFDB, FDA and FFDA, as well as 4,4-oxydianiline (4,4'-Oxydianiline, ODA), p-.
Phenylenediamine (pPDA), m
-Phenylenediamine (mPDA),
p-Methylenedianiline (para-Methylenedianyline, pMD)
A), m-methylenedianiline (meta-Methylenedianiline,)
mMDA), bisaminophenoxybenzene (1,3-bis (3-aminophen)
oxy) aminee, 133APB), bisaminophenoxybenzene (1,3-b)
is (4-aminophenoxy) benzene, 134APB), bisaminophenoxyphenylhexafluoropropane (2,2'-bis [4 (4-aminoph)
exoxy) phage] hexafluoropropane, 4BDAF), bisaminophenylhexafluoropropane (2,2'-bis (3-aminopheny)
l) hexafluoropropane, 33-6F), bisaminophenylhexafluoropropane (2,2'-bis (4-aminophenyl) hexafluoro
opropane, 44-6F), bisaminophenyl sulfone (bis (4-amin)
ofphenyl) sulfone, 4DDS), bisaminophenyl sulfone (bis (bis)
3-aminophenyl) sulfone, 3DDS), cyclohexanediamine (
1,3-Cyclohexanediamine, 13CHD), cyclohexanediamine (1,4-Cyclohexaneediamine, 14CHD), bisaminophenoxyphenylpropane (2,2-Bis [4- (4-aminophenoxy) -ph).
enyl] propane, 6HMDA), bisaminohydroxyphenylhexafluoropropane 2,2-Bis (3-amino-4-hydroxy-phenyl) -h
exafluoropropane, 6FAP), bisaminophenoxydiphenyl sulfone (4,4'-Biz (3-aminophenoxy) diphenyl sulf)
It can include one or more selected from one, DBSDA), and is not limited to the types mentioned here.

On the other hand, the acid dianhydride used in the present invention is 4-, in addition to PMDA, 6FDA and BPDA.
(2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride (TDA), benzophenone tetracarboxylic acid dianhydride (3,3,4) , 4-Benzophenone tetracarboxylic
dianhydride, BTDA), oxydiphthalic acid dianhydride (4,4-Oxyd)
Ifthalic dianhydride (ODPA), biscarboxyphenyldimethylsilane dianhydride (Bis (3,4-dicarboxyphenyl) dimet)
hyl-silane dianhydride, SiDA), bisdicarboxyphenoxydiphenyl sulfide dianhydride (4,4-bis (3,4-dicarboxyph)
enoxy) diphenyl sulfide dianhydride, BDSDA
), Sulfonyldiphthalic anhydride (Sulfonyldiphthalicanhyd)
ride, SO2DPA), cyclobutane tetracarboxylic dianhydride (Cyclobut)
ane-1,2,3,4-ttracarboxiclydianhydride,
CBDA), Isopropyridenephenoxybisphthalic anhydride (4,4'-(4,4'-)
Isopropylidenediphenoxy) bis (physical anh)
It can include one or more selected from ydride), 6HBDA), and is not limited to the types mentioned here.

In one embodiment of the present invention, the above-mentioned diamine and acid dianhydride components are included in the polymerization reaction.

The conditions at the time of the reaction are not particularly limited, but the reaction temperature is preferably 0 to 80 ° C., and the reaction time is preferably 2 to 48 hours. Further, during the reaction, it is more preferable that the atmosphere is an inert gas such as argon or nitrogen.

The organic solvent for the solution polymerization reaction of the monomer is not particularly limited as long as it is a solvent that dissolves the polyamic acid. Known reaction solvents include m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc),
Dimethyl sulfoxide (DMSO), acetone, ethyl acetate, diethyl formamide (DEF), diethyl acetamide (DEA), propylene glycol monomethyl ether; PGM
E), Propylene glycol monoethyl ether acetate (Propylene gl)
ycol monomethyl ether acetate; PGMEA), ethyl lactate, 3-methoxy-N, N-dimethylpropionamide (
3-Methoxyxy-N, N-Dimethylpropionamide), 3-Butoxy-N, N-Methylpropionamide (3-Butoxy-N, N-methylp)
One or more polar solvents selected from ropionamide) are used. Besides,
A low boiling point solvent such as tetrahydrofuran (THF) or chloroform, or a low water absorption solvent such as γ-butyrolactone can be used. The type is not limited to those mentioned here, and such a solvent may be used alone or in combination of two or more depending on the purpose.

The content of the organic solvent is not particularly limited, but in order to obtain an appropriate molecular weight and viscosity of the polyamic acid solution, the content of the organic solvent is preferably 50 to 95% by weight, more preferably 70 to 90% by weight of the total polyamic acid solution. preferable.

According to another embodiment of the present invention, bistrifluoromethylbenzidine (2,2'-bi).
Repeating units derived from s (trifluoromethyl) benzidine, TFDB) and pyromeritic acid dianhydride (1,2,4,5-benzene terraca).
A first block structure containing a repeating unit derived from rboxylic dianhydride, PMDA) and bistrifluoromethylbenzidine (2,2'-bis (t).
Repeat units derived from rifluoromethyl) benzidine, TFDB) and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4). , 4-Biphenyl
Provided is a polyamic acid comprising a second block structure comprising a repeating unit derived from one or more selected from ylttracarboxyldic dyandride, BPDA).

The polyamic acid is preferably produced by the above-mentioned production method.

The polyamic acid produced by the above-mentioned production method already contains a first block structure and a second block structure in which one type of diamine is contained in a specific content by dividing and charging one type of diamine. Compared with the polyamic acid produced by the method of adding all at once as in the method, the effect that the coefficient of linear thermal expansion is improved without lowering the yellowness and the permeability can be obtained.

<PMDA in the first block structure> vs. <6FDA in the second block structure
And one or more selected from BPDA> have a molar ratio of 90 to 25:10 to 75, preferably 90 to 30:10 to 70.

<PMDA in the first block structure> and <6FD in the second block structure
If one or more selected from A and BPDA> is out of the range of the molar ratio, there may be a problem that it has a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm / ° C. or more.

Further, the above-mentioned <PMDA in the first block structure> vs. <6 in the second block structure
The molar ratio of FDA> is 90-70: 10-30, preferably 90-75: 10-25.

<PMDA in the first block structure> and <6FD in the second block structure
When A> is out of the range of the molar ratio, if the ratio of PMDA is higher than the range, there may be a problem that the coefficient of linear thermal expansion becomes very low but the yellowness becomes very high, and the ratio of 6FDA becomes very high. If it is higher than the range, the yellowness has the advantage of being very low, but there may be a problem that the coefficient of linear thermal expansion increases.

Further, the above-mentioned <PMDA in the first block structure> vs. <B in the second block structure
The molar ratio of PDA> is 90 to 25:10 to 75, preferably 85 to 30:15 to 70.

<PMDA in the first block structure> and <BPD in the second block structure
When A> is out of the range of the molar ratio, if the ratio of PMDA is higher than the range, the coefficient of linear thermal expansion becomes very low, but there may be a problem that the yellowness becomes very high, and the ratio of BPDA. If is higher than the range, there is an advantage that the yellowness is lower than that of PMDA, but there may be a problem that the coefficient of linear thermal expansion increases.

In one embodiment of the present invention, the molar ratio of PMDA in the first block structure to 6FDA in the second block structure to BPDA in the second block structure is 90 to.
It is 50: 5 to 30: 5 to 20, preferably 90 to 55: 5 to 30: 5 to 15.

<PMDA in the first block structure> and <6FD in the second block structure
If A and BPDA> are out of the above molar ratio range, they have a yellowness of 10 or more or 30p.
There may be a problem with a coefficient of thermal expansion of pm / ° C or higher.

Further, the second block structure including the above <repeating unit derived from TFDB> and <repeating unit derived from one or more selected from 6FDA and BPDA> is bisaminophenylfluorene (9,9-Bis). (4-aminophenyl) fluorene,
FDA) and bisfluoroaminophenylfluorene (9,9-Bis (3-flu)
1 selected from oro-4-aminophenyl) fluorene, FFDA)
It can further include repeating units derived from more than a species. The above <FDA and FFDA
When one or more selected from> is further contained, the effect of improving the glass transition temperature can be obtained.

The above <one or more selected from FDA and FFDA> is contained in a content of 1 mol% to 20 mol%, preferably 1 to 10 based on the total mole of diamine. The above <FDA and FF
When one or more selected from DA> is out of the above range, it is possible that the content is small and there is almost no effect of improving the glass transition temperature when it is less than 1 mol%, and yellow when it exceeds 20 mol%. There may be a problem that the degree and the coefficient of thermal expansion decrease.

The method for producing the polyimide resin by imidizing the above-mentioned polyamic acid is not particularly limited, and a conventionally known method can be used. The method for imidizing the polyamic acid can be carried out by applying a thermal imidization method, a chemical imidization method, or a thermal imidization method and a chemical imidization method in combination, and the thermal imidization method. Is more preferred. More preferably, the solution subjected to the chemical imidization method is precipitated, purified and dried, and then dissolved in a solvent again before use. This solvent is the same as the solvent mentioned above. In the chemical imidization method, a dehydrating agent typified by acid anhydride such as acetate anhydride and an imidization catalyst typified by tertiary amines such as isoquinolin, β-picoline, and pyridine are applied to a polyamic acid solution. It is a method to make it. The thermal imidization method can be used in combination with the chemical imidization method, and the heating conditions can be changed depending on the type of the polyamic acid solution, the thickness of the film, and the like.

According to another embodiment of the present invention, a polyimide film produced from the polyimide resin is provided.

In the polyimide film, after imidizing the obtained polyamic acid solution, the imimized solution is put into a second solvent, and the polyimide film is precipitated, filtered, and dried to obtain the solid content of the polyimide resin, and the obtained polyimide is obtained. It can also be obtained from a polyimide solution in which a resin solid content is dissolved in a first solvent through a film forming step.

That is, the above-mentioned polyamic acid is prepared into a polyimide resin by a chemical imidization method, then precipitated and dried, dissolved in a solvent to form a solution, and applied to a support. The applied solution is filmed on the support by dry air and heat treatment.

The same solvent as that used for polymerizing the polyamic acid solution can be used as the first solvent, and the second solvent is more polar than the first solvent in order to obtain the solid content of the polyamic acid resin. A low solvent is used, and specifically, it may be one or more selected from water, alcohols, ethers and ketones. Here, the content of the second solvent is not particularly limited, but is preferably 5 to 20 times by weight with respect to the weight of the polyamic acid solution.

The film formation temperature condition of the applied film is preferably 250 to 500 ° C., and as the support, an aluminum foil, a circulating stainless belt, a stainless drum, or the like can be used.

The treatment time required for film formation varies depending on the temperature, the type of support, the amount of the applied polyamic acid solution, and the mixing conditions of the catalyst, and is not limited to a fixed time. It is preferably performed in the range of 5 to 30 minutes.

The heat treatment is performed in a temperature range of 100 to 500 ° C. and a treatment time in a range of 1 minute to 30 minutes. After heat treatment to dry and imidization is completed, it is peeled off from the support.

The thickness of the obtained polyimide film is not particularly limited, but is 10 to 250.
The range is preferably in the range of μm, more preferably 10 to 100 μm.

Further, the polyimide of the present invention means a term that can include any polyimide-based polymer such as polyimide-amide.

The polyimide film produced by the present invention has a coefficient of thermal expansion (Coef) at 50 to 350 ° C.
The fiction of Thermal Expansion) is preferably 30 ppm / ° C. or lower.

The polyimide film produced by the present invention has UV based on a thickness of 10 to 100 μm.
When measuring the transmittance with a spectrometer, the transmittance at 550 nm is 85% or more, preferably 90%.
That is all.

The polyimide film has a yellowness of 10 or less, preferably 5 or less, based on a film thickness of 10 to 100 μm.

[Mode for Carrying Out the Invention]
Hereinafter, the present invention will be described in detail based on examples, but the scope of the present invention is not limited to the following examples.

<Example 1>
N-methyl-2-pyrrolidone (NMP) 27 while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor.
After charging 3.882 g, after dissolving 28.821 g of TFDB, PMDA 19.6
After adding 31 g, the mixture was stirred for 3 hours. Then, after additionally dissolving 3.202 g of TFDB, 4.443 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 2>
As a reactor, N-methyl-2-pyrrolidone (NMP) 284 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 922 g, after dissolving 25.618 g of TFDB, PMDA 17.45
After adding 0 g, the mixture was stirred for 3 hours. Then, after adding 6.405 g of TFDB, 6FDA 8.885 g was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 3>
As a reactor, N-methyl-2-pyrrolidone (NMP) 295 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 963 g, after dissolving 22.416 g of TFDB, PMDA 15.26
After adding 8 g, the mixture was stirred for 3 hours. Then, additionally, after dissolving 9.607 g of TFDB, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then 30.
It was isothermally treated for 1 minute and cured. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 4>
As a reactor, N-methyl-2-pyrrolidone (NMP) 295 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 963 g, after dissolving 9.607 g of TFDB, 6FDA 13.328
After adding g, the mixture was stirred for 3 hours. Then, in addition, after dissolving 22.416 g of TFDB, 15.268 g of PMDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 5>
As a reactor, N-methyl-2-pyrrolidone (NMP) 281 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 419 g, after dissolving 16.012 g of TFDB, PMDA 10.90
After adding 6 g, the mixture was stirred for 3 hours. Then, additionally, after dissolving 16.012 g of TFDB, 14.711 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 350 ° C., and then 10
It was isothermally treated for 1 minute and cured. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 6>
As a reactor, N, N-dimethylacetamide (DMAc) 2 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
After charging 83.576 g, after dissolving 13.450 g of TFDB, PMDA 9.1
After adding 61 g, the mixture was stirred for 3 hours. Then, additionally, after dissolving 23.825 g of TFDB and 1.384 g of FFDA, 22.949 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 20% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate and then treated with hot air at 80 ° C. for 20 minutes. 3
After reaching 50 ° C., it was isothermally treated for 10 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 7>
As a reactor, N-methyl-2-pyrrolidone (NMP) 288 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 638, after dissolving 22.416 g of TFDB, PMDA 15.268
After adding g, the mixture was stirred for 3 hours. Then, additionally, after dissolving 9.607 g of TFDB, 8.885 g of 6FDA was added and reacted for 3 hours. Finally BPDA 2.942g
Was put in and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 8>
As a reactor, N-methyl-2-pyrrolidone (NMP) 288 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 638, after dissolving 22.416 g of TFDB, PMDA 15.268
After adding g, the mixture was stirred for 3 hours. Then, in addition, after dissolving 6.405 g of TFDB, 8.885 g of 6FDA was added and reacted for 3 hours. Finally TFDB 3.202g
Was dissolved, and 2.942 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then 3
It was isothermally treated for 0 minutes and cured. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Comparative Example 1>
As a reactor, N-methyl-2-pyrrolidone (NMP) 268 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 362 g, after dissolving 32.023 g of TFDB, PMDA 20.72
After adding 1 g, the mixture was stirred for 3 hours. Then, 6FDA 2.221 g was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained.
After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then gradually cool and
A polyimide film was obtained by separating from a glass plate.

<Comparative Example 2>
As a reactor, N-methyl-2-pyrrolidone (NMP) 295 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 963 g, after dissolving 32.023 g of TFDB, PMDA 15.26
After adding 8 g, the mixture was stirred for 3 hours. Then, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Comparative Example 3>
As a reactor, N-methyl-2-pyrrolidone (NMP) 295 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 963 g, after dissolving 32.023 g of TFDB, 6FDA 13.32
After adding 8 g, the mixture was stirred for 3 hours. Then, 15.268 g of PMDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Comparative Example 4>
As a reactor, N-methyl-2-pyrrolidone (NMP) 301 while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler.
.. After charging 483 g, after dissolving 32.023 g of TFDB, PMDA 14.17
After adding 8 g, the mixture was stirred for 3 hours. Then, 15.549 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80 ° C. for 20 minutes, reached 370 ° C., and then isothermally treated for 30 minutes to cure. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

The physical properties of the polyimide films produced in the above Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1 below.

(1) Transmittance (TT) measurement The transmittance was measured three times at 550 nm using a UV spectrometer (Konica Minolta, CM-3700d), and the average value is shown in Table 1.

(2) Measurement of yellowness (YI.) The yellowness was measured according to the ASTM E313 standard using a UV spectrometer (Konica Minolta, CM-3700d).

(3) Coefficient of thermal expansion (CTE) measurement Using TMA (TA Instrument, Q400), the linear coefficient of thermal expansion at 50 to 350 ° C. was measured twice according to TMA-Measode. The size of the specimen is 4m
The load was 0.02 N, the temperature was 10 ° C./min, and the temperature was 10 ° C./min. Since the film may be formed and residual stress may remain in the film due to heat treatment, the residual stress is completely removed by the first operation (Run), and then the second value is presented as the actual measured value. did.

As can be seen from Table 1, when the Examples and the Comparative Examples are compared with each other, in the case of Examples 1 to 8 in which the TFDB is separately charged, all of the yellowness, the transmittance and the coefficient of linear thermal expansion are all.
Although they are satisfied with an excellent level, the transmittance in Comparative Example 1 is significantly reduced, and Comparative Example 2 is satisfied.
Nos. 4 showed physical properties in which the coefficient of linear thermal expansion was significantly reduced.

From this, it was found that in Examples 1 to 8, the trade-off relationship between the yellowness and the coefficient of linear thermal expansion was overcome by inputting the TFDBs separately.

When the primary acid dianhydride is PMDA and the secondary acid dianhydride is 6 FDA, P
The content of MDA is preferably more than 65 mol% in order to have a coefficient of linear thermal expansion of 30 ppm / ° C. or less, and preferably not more than 90 mol% in order to prevent a decrease in yellowness. .. Further, the same effect can be obtained by using BPDA as the secondary acid dianhydride, and even if FFDA is additionally applied, the coefficient of linear thermal expansion can be improved by dividing the TFDB. .. Looking at Examples 3 and 4, the acid dianhydride of the primary input is PM.
It can be seen that the improvement effect is greater in the case of DA than in the case of 6FDA. Then, looking at Examples 7 and 8, when the tertiary acid dianhydride is applied, the larger the divided input of TFDB, the more.
It was confirmed that the coefficient of linear thermal expansion was further improved.

Claims (18)

Bistrifluoromethylbenzidine (2,2'-bis (trifluorometh)
Diamine containing yl) benzidine, TFDB) and pyromeritic acid dianhydride (1,
2,4,5-benzene terracarboxylic dianhydrid
At the stage of adding the acid dianhydride containing e, PMDA),
Bistrifluoromethylbenzidine (2,2'-bis (trifluorometh)
Diamine containing yl) benzidine, TFDB) and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4) -Biphenyltellacarboxyli
c. The stage of adding an acid dianhydride containing one or more selected from dianhydride (BPDA), and
A method for producing a polyamic acid, including. The molar ratio of <PMDA> to <one or more selected from 6FDA and BPDA> is
The method for producing a polyamic acid according to claim 1, wherein the content is 90 to 25:10 to 75. The method for producing a polyamic acid according to claim 1, wherein the molar ratio of <PMDA> to <6FDA> is 90 to 70:10 to 30. The method for producing a polyamic acid according to claim 1, wherein the molar ratio of <PMDA> to <BPDA> is 90 to 25:10 to 75. The molar ratio of <PMDA> to <6FDA> to <BPDA> is 90 to 50: 5 to 30.
: The method for producing a polyamic acid according to claim 1, wherein the content is 5 to 20. The diamine is bisaminophenylfluorene (9,9-Bis (4-ami).
nophenyl) fluoride, FDA), and bisfluoroaminophenylfluorene (9,9-Bis (3-fluoro-4-aminophenyl) fluoro
The method for producing a polyamic acid according to claim 1, wherein one or more selected from rene and FFDA) are further added. The above-mentioned bisaminophenylfluorene (9,9-Bis (4-aminophenyl)
) Fluorene, FDA) and bisfluoroaminophenylfluorene (9,9-B)
is (3-fluoro-4-aminophenyl) fluoride, FFDA)
The method for producing a polyamic acid according to claim 6, wherein one or more selected from the above is added in a content of 1 mol% to 20 mol% with respect to the total mol of the diamine. Bistrifluoromethylbenzidine (2,2'-bis (trifluorometh)
Repeat units derived from yl) benzidine, TFDB) and pyromeritic acid dianhydride (1,2,4,5-benzene terracarboxylic dianhy).
A first block structure containing a repeating unit derived from drive, PMDA) and
Bistrifluoromethylbenzidine (2,2'-bis (trifluorometh)
Repeat units derived from yl) benzidine, TFDB) and 2,2-bis (3,
4-Dicarboxyphenyl) Hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarbo)
A polyamic acid comprising a second block structure comprising a repeating unit derived from one or more selected from xylic dyandride, BPDA). <PMDA in the first block structure> vs. <6FDA in the second block structure
The polyamic acid according to claim 8, wherein the molar ratio of one or more selected from BPDA is 90 to 25:10 to 75. <PMDA in the first block structure> vs. <6FDA in the second block structure
The polyamic acid according to claim 8, wherein the molar ratio of> is 90 to 70:10 to 30. The above-mentioned <PMDA in the first block structure> vs. <BPDA in the second block structure
The polyamic acid according to claim 8, wherein the molar ratio of> is 90 to 25:10 to 75. <PMDA in the first block structure> vs. <6FDA in the second block structure
> The molar ratio of <BPDA in the second block structure> is 90-50: 5-30: 5-2.
The polyamic acid according to claim 8, which is characterized by being 0. The second block structure containing the above <repeating unit derived from TFDB> and <repeating unit derived from one or more selected from 6FDA and BPDA> is bisaminophenylfluorene (9,9-Bis (4-aminophenyl). ) Fluorene, FDA)
And bisfluoroaminophenylfluorene (9,9-Bis (3-fluoro-4-)
The polyamic acid according to claim 8, further comprising a repeating unit derived from one or more selected from aminophenyl) fluorene, FFDA). The polyamic acid according to claim 13, wherein the content of <one or more selected from FDA and FFDA> is 1 mol% to 20 mol% with respect to the total mole of diamine. A polyimide resin produced from the polyamic acid according to claim 8. A polyimide film produced from the polyimide resin according to claim 15. The polyimide film has a coefficient of thermal expansion (Coefficient) at 50 to 350 ° C.
The polyimide according to claim 16, wherein the polyimide (of Thermal Expansion) is 30 ppm / ° C. or less, the transmittance at 550 nm is 85% or more, and the yellowness is 10 or less when measured by a UV spectrometer. the film. An image display element including the polyimide film according to claim 16.