JPS6081154A - Recovering process - Google Patents

Abstract

PURPOSE:To recover a tetracarboxylic acid and an aromatic diamine from off- grade aromatic polyimide, in high yield, by hydrolyzing the polyimide in the presence of excess alkali at a specific temperature, and neutralizing the resultant tetracarboxylic acid and aromatic diamine with excess alkali and acid to effect the precipitation and separation of the compounds. CONSTITUTION:An off-grade aromatic polyimide of formula (R and R' are aromatic ring) is hydrolyzed at 150-230 deg.C in the presence of 4.0-4.8mol of an alkali (e.g. sodium hydroxide) based on 1mol of the polyimide unit until the imide bond is essentially completely broken. The produced aromatic tetracarboxylic acid and aromatic diamine are dissolved in an alkali solution and acid solution, respectively, decolorized with activated carbon, and added with more than neutralization equivalents of acid and alkali to make the solutions to acidic and alkaline, respectively. The precipitated aromatic carboxylic acid the aromatic diamine are recovered by removing the entrained diamine and carboxylic acid components.

Description

DETAILED DESCRIPTION OF THE INVENTION The role played by the functional n (near 'Iy') group polyimide is significant.

``3'' (one or two or more 3 br in the molecule) 3'J aromatic detracarboxylic acid dianhydride and aromatic ring in the molecule The polyimide produced by fO synthesis with a single aromatic diamine has the following structure in order of one R, and is used for film formation).
From the viewpoint of the strength of the ilm, for example, the logarithmic viscosity (measured at 50°C using chlorophenol as a solvent) is reduced to 2.0 or more, especially about 2.0 to 4.0. Polymers are now in practical use.

(However, R and R'' are residues containing an aromatic ring.)
However, aromatic JFX polyimide requires 111 features, especially heat resistance! In some fields, there are strict requirements for aromatic polyimide's ability to perform 11, and products may be discarded as substandard products due to the presence of a small amount of glue in the formed film or the presence of RF micro pinholes. It's not that small. Also'! ! At the time of J film, (, 1,) r r l) both ends become gripping margins for the machine, so the n) i side is later cut off at 1: east, but at n; t, 11 of aromatic polyimide. (ShiruyJ Kozokude 1~Lacarvone dianhydride and Banko diilmin are extremely expensive chemicals, and the parts that are discarded are aromatic polyimide!)! J'! +'i, -]
J's influence on S1 is great.

It is well known that these Tozan fIA polyimides are decomposed by heating in the presence of alkaliba, but they are completely converted into single M units of Yoshiyama 11'A phthracarboxylic 4p and Chikara group diamines. Min F ((l), subjecting this again to the m condensation reaction σ)
There is no known way to do so.

The reason (good for hydrolysis) -r mido bond ll'
In the case before i′, 11111nl+ reaction of the carboxyl group is accompanied, and the removal of the carpo-1-syl group! 11
Article 911 Article 1'1 (1,
At the end, the imide bond is not completely dissociated, and the polyimide A 7- remains. incense b x ji j
For example, the six colors of ``min'' (nζ5 colors) are -8. The presence of polyimide A oligomer (311, unpopular methanol in the recovered material)) can be clearly confirmed by Mr.

Calcium mixed into the raw material 3. (n of
IJ nil to J, the result is 11 components of charcoal/AI/recarbon, 11 components of charcoal, poly7mide oligomer, etc., I' (1 of harmful substances) of polycondensation reaction. When using 1'l of the recovered raw material which has a size of 0.0596 J, the logarithmic viscosity becomes 13 in the polycondensation reaction.
Aromatic polyimide with f of 2.0 or more.G, L, polycondensation reactivity? 'b < , 3
3) Reusable as 'J aromatic polyamide Harahiro': 1)
Regarding the recovery method of dianhydride detrancarboxylic acid dianhydride and aromatic mhχ diamine, it was found that
Completed fl Ming.

In other words, the present invention has the advantage that it is possible to hydrolyze aromatic polyimide to J, C aromatic %/J, which cannot be used as a molded product, etc.
X-j'-l Lacarvone filf dianhydride,! 3Jζ
JJ-C1 is a method for simultaneously recovering aromatic diamines and aromatic diamines.
~1.0 per polyimide unit of aromatic rrI group polyimide
~4.8 times the molar coexistence of l-fluoride 150-230
At a temperature of 71°C, the aromatic hapolyimide is hydrolyzed to the extent that no imide bonds remain in the nail. After avoiding contact with 1vj, acid in an amount equal to or more than the neutralization equivalent and 1fluorkali are added to precipitate the noko group detracarboxylic acid Jj J, bi'y) 7mine, and these are separated into A method for recovering aromatic hi'l-lacarvone dianhydride and aromatic diamines having a 1-# characteristic of 111'Ll will be described.

The aromatic polyimide used in this invention has a heat resistance of 1! There is no restriction if I is right1-rub.

The h method of the present invention (one-dimensional explanation η) is 11.O to 4.84ES for aromatic polyimide and polyimide units.
71 - 11 - 11 sodium chloride, an alkali such as 1'1 potash or ammonia, and water are put into a durable reactor such as 71-1-1 crepe, and the gas phase is inert with nitrogen or blown acid gas. After replacing with 11 gas, 1 5 0 ~ 2 3
0 - to l/) Q4'i lIIl (1) Vortex 1
The polyimide is hydrolyzed until it undergoes heating and undergoes r'fl crystals and substantially no imide bonds are present.

The 1'lrkih''A tetracarboxylic acid produced by hydrolysis hγ exists in aqueous solution as a j'lukaline salt, and Yoshizai P., Diamine Banyo, Cold Julisu, A-1. Since the precipitate is at the bottom of the tube, separate it by filtration.Add 1 to the filtrate)
After adding J:ru 11+2 (Ha treatment to the 1-grade charcoal, add inorganic ^1 such as 1-product acid, +gt fiQ, etc., or right-pressing agents such as GI and ml acid to change the astringency to acid (I). The group detoshicarboxylic acids are precipitated and recovered by filtration, washing with water, and drying. It is necessary to make the liquid acidic by adding more than an equivalent amount of acid in order to remove the mixed diamine component.Recovered 5'
The 3-carboxylic dianhydride is heated in an inert gas stream with 1111 water and converted into an aromatic tracarboxylic dianhydride, which is then used as a raw material for monoaromatic polyimide. However, a purification operation may be added before or after the anhydrous millet.

In this way, 90% of non-standard aromatic polyimide
Aromatic te-racarboxylic dianhydride can be recovered with the following two high yields.

On the other hand, the precipitate filtered out after the hydrolysis is '3L'j Kosin diamine, which is subjected to the following treatment to remove foreign matter and to remove the two colors.

Add the precipitate to an aqueous solution of acids such as hydrochloric acid, sulfuric acid, ginseng, Nishi 101, etc., and apply two-color treatment to activated charcoal (filter).

Next, 7JJ soda, 1!1 potash of Xun, and noflukali of 7 points of ammonino were added to the rdn solution to make the C1 solution alkaline.

The precipitated aromatic diamine is collected by filtration, washing with water, and drying. Here, n! Jf! During precipitation from I solution, it is necessary to add an alkali (more than 11 equivalents + yI) to make the solution alkali 111 and 121 in order to remove the carboxylic acid components that have entered the solution. Therefore, it is possible to recover katazane hk dinomine from non-standard aromatic polyimide with a yield of over 90%. Of course, purification operations such as four-way purification may be added.

In this invention, the alkali used for hydrolysis is caustic soda, caustic potassium, or ammonia, but the rtX used is 4.04H'5 for the polyimide bond.
It is necessary to add more than 10% of the amount, and if there is less, the decomposition reaction will proceed completely. A low molecular weight A oligomer that connects the polyimide bonds is formed. In addition, excessive use accelerates the acid reaction (;?), so θf;
<>/1.0 to 4.8 (for polyimide bonding position)
n7ru culm is optimal. Water addition j) The river of water at the time of Fn should have enough flow to dissolve the alkali salt of the produced 18 aromatic acid 1~lacarboxylic acid, but in general, 5 to 204 for small amounts of polyimide
8 culms are enough.

J+ A: In this invention, when hydrolyzing polyimide, the time required for imide bonds to substantially disappear is 7 hours during the warm polishing of the hydrolysis.
1; 711. at 50°C. 'i, 511 at 170℃
．． Between lr, 200℃'c, 3,511;'1, 2
2.5 hours at 30°C is suitable.

Below is the actual f+I! i Accepted Example A3 and Comparative Example.

Example 1゜3.3-14.4'-biphenylde1-lacarvone n!
; dianhydride (hereinafter abbreviated as 13PDA) and diaminosyphinyl J: -)'ru (hereinafter DΔl) EdoF3
The gripping area of 1f F group polyimide 115 produced by polycondensation of
1 number viscosity (ηi++l+) is 3.5] is 309
, caustic soda 11.59 (for polyimide Ai Q;?J
300 ml of distilled water was poured into an A-1 crepe with an internal volume of 430 ml. After the gas phase was ground with nitrogen, the product was 190 ml. Hydrolyze the mixture by stirring for 4 hours at C.C. and filter the contents of the cold 7.1140'A-1-91 knob.Add one portion of powdered activated carbon to the filtrate and stir for 30 minutes. After filtering, add 1 portion of activated charcoal and add 4 portions of concentrated hydrochloric acid (Uni) to the filtrate.
A, Fl @filtration, washing with water, drying at 60°C to -Ik reduction II, partially methyl esterifying, and then elemental analysis and gas 0-mass analysis: 3.3'.

4.4---Bif J Nirula 1-lacarvone li9 (hereinafter referred to as B1) (abbreviated as l-A)
(The concentration of 2 carbonic acid components was as small as 0.014%.Also, the recovered 13'Ii) 1ΔG, 1 Because it completely dissolves in methanol and does not contain any insoluble matter. , it was observed that the polyimide bond did not contain any A ribomer at 11°1. In a nitrogen stream, 240
'C'' C1G time f3 P Heating TA j1; 2 water l
The recovery rate of 1 as 13P[)A was 92.6% for the aromatic polyimide containing 1.
, l Furthermore, after hydrolysis m, 30 m1 of a1 is added to each filtered solid.
Add hydrochloric acid and 270ml of distilled water and dissolve.
Add 111g and 117g for 30 minutes. stirred i
The crystalline charcoal was filtered and combined for 11 minutes. 15 ml of caustic soda in the stock solution
1 J was added and stirred, and the precipitate precipitated was filtered and washed with water (dried under reduced pressure at 60° C. overnight to obtain a white powder).

A portion was subjected to elemental analysis and gas chromatography analysis and was found to be pure 1]80E (ηCm). The recovery rate was 91°'1%.

B P I) Δ5.88q(
20 mmol>I) ADE4. , Olg (20 mmol) was prepared by the method described in JP-A-55-65227 to obtain C11]-L1F1'nor91.6<1wo'7
B'ljA Toshi-C1601'r'-C' 111.
The logarithmic viscosity (ηinl+,) at 50°C is 2.83 for J aromatic polyimide. This 11f1 is a sufficient number M foot. This shows that l!'!i condensation was achieved as much as possible.

ηinh, = l n (η/η.)/Nikode η: Electrical formation η of the polyimide solution. :Solvent (+)-chlorophenol) viscosity rxC:polyimide m (o/100o) 1τ film was made by the method described in JP-A-55-65227 to produce a film with a thickness of 30μ. Create the tensile strength L(
Measure l +3 and elongation (at break) L/Ic Toco 7
), each 1z 23, 9ku/m11I', 83%
Met.

Example 2 In the same manner as in Example 1, a non-standard film 30 (+) of yi fragrance polyimide was hydrolyzed at 150° C. for 7 hours to form 1'
31) I) A and 1)△1) E balls were obtained with recovery rates of 91.1% and 93.3%, respectively. Recovered B P 1)
The atcr of the decarboxylated component in -A was sufficiently low at 0.011%, and the polyimide oligomer was not at all goldstone.

When polycondensation was carried out in the same manner as in Example 1 using 1ift i'l of these recovered materials, the logarithmic viscosity at 50°C was 1.1.
The tensile strength Iff of the polyimide film was 43 and the elongation was 24.1.
kg/m1+F, Onibi 85%.

Example 3 Hydrolysis FIZ of aromatic polyimide was carried out in a humid environment at 230°C for 2.5 hours, except that formic acid was used instead of hydrochloric acid.
In the same manner as in Example 1, C31) DΔ and 1]ΔDE
The recoveries were 193.11%, 92, and 6%, respectively, resulting in 4!77 cases.

The concentration of the 182 carbonate component in the recovered +3Pl)Δ was 0.01896 and 11(ri), and the polyimide oligomer was not at all C1.
Polycondensation was carried out in the same manner as in Example 1 using
The λ・1 number viscosity of R1) is 2.97, which is a fully satisfactory value, and the tensile strength of the polyimide film is 23°6ko.
/rnF, the elongation was 82%.

Comparative Example 1 Using 26.29 mols of caustic soda (10 times the mole per polyimide unit), Kobaka conducted the same experiment as in Example 1, and calculated the recovery rates of Bl)-1-A and 1]ΔD[, respectively. 92.4%, 92.1%, 11. Collection-FB
As a result of PTA analysis, polyimide oligomers were not present, but traces of decarboxylation components were found to be 0.00%. Furthermore, when polycondensation was carried out in the same manner as in Example 1, the logarithmic viscosity of the small condensate was as low as 1.63, which was a satisfactory l+f (but not quite). The tensile strength of polyimide film is 13.
7 kg/m1ffi, elongation was 45%.

Comparative Example 2 Hydrolysis was carried out at 130° C. for 15 hours using the method of Example 1, and 3% of BPT and 55.1% of DADE were recovered. As a result of BPTA analysis, the concentration of decarboxylated components was 0.
．． 00% and I [but polyimide oligomer is 7.3
% was also mixed in. The recovered BPTA is made anhydrous and B
l) After setting D A, do the same as in Example 1! Although F polycondensation was carried out, the viscosity of the reaction solution did not increase at all.

Comparative Example 3 Hydrolysis was carried out in the same manner as in Example 1 at 250°C for 1 hour, and 13[]'Δ and D A DE were each 9
4.696.9/1.1% return rate, 1st discipline. [31)
As a result of analysis of 'rA, polyimide oligomers were not included in i, but the concentration of l121u2 acid component was 1.6.
It was as high as 5%. As a result of the polycondensation test, the logarithmic calculus at 50°C was 1.16, and the tensile strength If of the polyimide film was
Get 7, 6 k (1/wvF, elongation is 23%
This was a low and unsatisfactory value.

Claims (1)

[Claims] [Claims] When hydrolyzed from polyimide (fragrance that can no longer be used as a molded product), it is possible to obtain lAte1-lacarboxylic acid dianhydride J3 J, bi'i''J xylic group diamine]1 In the method of recovering and covering the polyimide of J'''J polyimide, the imide bond is substantially removed at a temperature of 150 to 230°C. Polyimide was hydrolyzed to yJ?1'I using culm I which does not remain, and the obtained 'y''J^f Para 1~
Aqueous alkali solution and aqueous acid solution of acarboxylic acid, Jζ and 3S aromatic diamine are brought into contact with activated charcoal.
After neutralization, after the first month of the month, add 1 l of fFl 83 and alkali and separate the tetracarboron (r7-J to 14 and 16) ya IN.
5' Method for recovering tracarboxylic dianhydride and aromatic diamine.