JPS58189260A - Production of polyimide varnish - Google Patents

Abstract

PURPOSE:To produce a polyimide varnish which gives a heat-resistant substance, by reacting an org. tetracarboxylic acid anhydride with a diamine in a suspension of a specified polyimide powder to form a polyimide precursor. CONSTITUTION:An org. tetracarboxylic acid anhydride (A) of formula I (wherein R1 is a 6-20 C arom. ring or arom. heterocyclic ring) is reacted with a diamine (B) of formula II (wherein R2 is R1) in a ratio of A/B of 0.7-1 in a polar solvent such as dimethyl sulfoxide at 40-80 deg.C to obtain a polyimide precursor soln. having a concn. of 20-35%. This soln. is heated at an imide-cyclizing temp. (100-200 deg.C) to precipitate polyimide powder, whereby a suspension of polyimide powder is obtd. Them components A and B are added to this suspension and reacted at 40-80 deg.C to form a polyimide precursor, whereby a polyimide varnish contg. polyimide powder and the precursor in a weight ratio of 70/30- 40/60 can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a novel polyimide powder-containing polyimide varnish that provides a heat-resistant material.

Conventionally, there are two methods for producing powder-containing polyimide varnish.
The conventional method has been to add inorganic or organic powder to ordinary polyimide varnish and mix and disperse it using mechanical methods such as stirring.

However, with this method, it is difficult to uniformly disperse a large amount of powder in the varnish, and when the varnish is observed under a microscope, a large number of secondary aggregates are seen.

For example, when this face is used as an ink for screen printing, the ink does not easily escape from the screen, making it impossible to print multiple times. The coating film cannot be maintained.

The object of the present invention is to disperse a large amount of powder uniformly in the varnish. An object of the present invention is to provide a method for producing polyimide varnish.

The present invention has the following configuration to achieve the above object.

That is, a tetraorganic carboxylic acid anhydride diamine is reacted in a solvent, the obtained polyimide precursor solution is heated at the imide ring closing temperature to precipitate polyimide powder, and in the suspension of the obtained polyimide powder, The present invention is characterized by a method for producing a polyimide varnish, in which a tetraorganic carboxylic acid anhydride and a diamine are reacted to form a polyimide precursor.

Tetra organic carboxylic acid anhydride solution applied to the present invention,
It is represented by the general formula OgSg]R1(g)0, and R4 in the same formula is an aromatic ring or aromatic heterocycle having 6 to 20 carbon atoms, and the carbonyl group is bonded to the ortho or peri position. Examples of R1 include phenyl group,
naphthalene group, perylene group.

Typical examples include, but are not limited to, a diphenyl group, a diphenyl ether group, a diphenylsulfone group, a 2.2'-:/phenylpropane group, and a benzophenone group. Particularly desirable are phenyl groups and benzophenone groups.

The tetraorganic carboxylic acid anhydride used as a raw material for the powder and the tetraorganic carboxylic acid anhydride used to form the polyimide precursor in the polyimide powder suspension may be the same or different substances.

Next, the cyamine applied to the present invention has the general formula H2N
It is represented by -R2-NH2, and R2 in the same formula consists of an aromatic ring or an aromatic heterocycle.

Examples of R2 include diphenyl ether group and phenyl group.

Typical examples include toluylene group, diphenylmethane group, and diphenylsulfone group.

= 6- Yes, even if these groups have substituents such as amino groups, acid groups, carboxyl groups, sulfonic acid groups, etc., as long as they do not adversely affect the powder form performance and heat resistance of these groups. good. In particular, diphenyl ether groups and phenyl groups are preferably used.

Note that the diamine used as a raw material for the powder and the diamine used to form the polyimide precursor in the suspension of polyimide powder may be the same or different substances.

The solvent used for reacting the tetraorganic carboxylic acid anhydride and the diamine is preferably a polar solvent from the viewpoint of polymer solubility. As examples of polar solvents, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl 2-pyrrolidone, hexamethylphosphoramide, etc. are preferably used.

As a method for reacting the above tetraorganic carboxylic acid anhydride and diamine in a solvent, the diamine is added and dissolved in the solvent with stirring, and after dissolving, the tetraorganic carboxylic acid anhydride is added and reacted. -Yuhi 4- Seiichi tetra organic carboxylic acid anhydride (A) and diamine (B
) The ratio (A>/(B) is preferably 0.7 to 1.0, preferably 08 to 0.95. If this ratio is less than 07, the phenol produced will have poor malleability, making it difficult to use for screen printing. When used as ink, it becomes difficult to print continuously.

The concentration of polyimide precursor in the polyimide precursor solution is 2
0 to 55%, and 23 to 30% is desirable. 20
If it is less than 35%, the proportion of powder in the face is too low and the shape retention of the pattern is poor when used as a screen printing ink, and if it is more than 35%, the viscosity of the polyimide precursor solution becomes high and stirring becomes difficult.

The reaction temperature for making the polyimide precursor solution is:
The temperature is preferably 40-80°C, preferably 40-60°C. 4
If the temperature is below 0°C, the polymerization rate will be slow, and if it is above 80°C, the molecular weight will decrease, which is not preferable.

The upper limit of the imide ring-closing temperature for precipitating imide powder from a polyimide precursor solution is the boiling point of the solvent used;
The lower limit varies slightly depending on the polymer, but is 100 to 200°C.
, preferably 110 to 170°C.

In order to make the polymerization of the 9th order polyimide precursor proceed more smoothly in the process of making a suspension of this polyimide powder,
Condensed water generated during imide ring closure may be removed by nitrogen flow, vacuum suction, or the like. - The polymerization temperature when polymerizing the polyimide precursor in a suspension of polyimide powder is 40°C to 80°C, preferably 40°C.
℃~60℃ is desirable. Below 40°C, the polymerization rate is slow, and above 80°C, the viscosity of the phenol decreases due to a decrease in molecular weight, which is undesirable.

H21J-R2-NH3 which is a diamine and 0<3>R' which is a tetraorganic carboxylic acid anhydride. As a method for adding 0〉o to polyimide 1\CO powder suspension, I(2N −
The weight ratio of R2 polyimide powder/polyimide precursor is 70
/30-40/60 preferably 65/35-45155
is desirable.

If the 6-polyimide powder is 7044 or higher, the film strength will decrease and the coating film will be prone to cracks. If it is less than 40%, when the varnish is used as an ink for screen printing, the shape retention of the printed pattern will be poor and good printed matter will not be obtained.

Furthermore, the general formula ○guZ:nR1gu3gn0 and H211
1-FU2WH2 polyimide powder and polyimide precursor may be copolymerized with other monomers or organic and/or inorganic powders may be added to the extent that the powder-forming ability, film-forming ability, and heat resistance are not significantly impaired. Good too.

The polyimide varnish manufactured by the manufacturing method described in the present invention has a solid content of 30 to 45% after drying in a hot air oven at 200°C for 2 hours, and a viscosity of BS type manufactured by Tokyo Keiki Co., Ltd. of 70.
It is of 0 to 2000 poise.

A small amount of this varnish was dropped onto a cover glass and the dispersibility of the particles was examined under an optical microscope at 150x magnification.

No secondary aggregation of particles was observed. Also, Cambridge
``Quantinet'' manufactured by Instrument Company
Regarding the sample diluted approximately 3 to 5 times using a 720 image processing analyzer, the particle size distribution was kept constant at a7 with a microscope magnification of 150 times. As a result, there were no coarse particles with a particle size of 30p or more, and 9 particles were uniformly dispersed. I found out that

Apply this varnish to LT-150T (
Using a screen printing machine (manufactured by Co., Ltd.), a soft error prevention film pattern consisting of about 200 patterns of 50μ in the size of 5mm x 6 plates was printed onto a silicon wafer, and 150 meshes were printed using a silicone squeegee to form an emulsion film. 100μ thick screen, printing cycle 3 minutes/sheet, squeegee angle #69 degrees, distance between screen and silicon wafer 28cm, printing speed 4.6 an/sec, printing pressure 1kg
/(2) As a result of printing with 2, the varnish came out well from the screen, and 100 silicon wafers could be coated continuously without any part of the pattern being chipped.Furthermore, Samurai , the coated film was heated to 80°C for +1 min.
Cure at 50°C for 30 minutes + 200'C for 30 minutes and 550°C for 30 minutes.

As a result of observation under a microscope with a magnification of 150 times, it was confirmed that a good coating film in which single particles were uniformly dispersed was formed.

The present invention will be described in further detail in Examples 8- vinegar.

Example 1 695.6 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) solvent was weighed into a three-necked 21 flask. To this, diaminodiphenyl ether (hereinafter abbreviated as DAE) 1
Add 20.1 g of the solvent at 50° C. while stirring to completely dissolve. After DAB was completely dissolved, 124.5 g of pyromellitic anhydride (hereinafter abbreviated as PMDA) was added little by little while stirring the solution.

DAB and PMDA react and the temperature in the system increases from 5 to 5 due to the heat of 2 reactions.
The temperature increases by 10℃. After reacting for 60 minutes, the temperature inside the system was raised to 80° C., and the reaction was further continued for 60 minutes. This time frame is kept in a closed system or under N2 flow. After reacting at 80° C. for 60 minutes, the system temperature was raised to 150° C. in a closed system with a cooling pipe attached to precipitate polyimide powder. 1.5-2 at 150℃
The reaction was carried out for 0 hours to precipitate polyimide powder, and then for 70 hours.
The temperature drops to ℃. DAB 94 when the temperature inside the system reaches 70℃
．． Add 3g of benzophenonetetracarboxylic anhydride (hereinafter referred to as BTDA) to t-<” (abbreviated as BTDA) 159.5g
and react.

9- After reacting for about 1 hour, use a BS viscometer (Tokyo Keiki Co., Ltd.)
Measure the viscosity using a 1000 to 200 poise product. If the viscosity is low, add a small amount of BTDA, if the viscosity is high, dilute with NMP. When the viscosity matches, let it react for another hour and take it out. It was confirmed using a microscope and an image processing analysis device that the varnish prepared by this method had good powder dispersibility despite the powder/binder ratio being 171.

The result of printing this varnish with a screen printing machine.

The varnish "released" well from the screen, and multiple printings were possible. Furthermore, as a result of curing the obtained coating film, a pattern consisting of a good polyimide film was obtained.

Example 2 -1 in Example 1! 11M instead of IMP single bath salt
P/ethyl cellosolve (hereinafter abbreviated as EC8) = 8571
A varnish was prepared in exactly the same manner as in Example 1 using the mixed solvent system of Example 5.

When the resulting varnish was printed using an LT-15G screen printer, it had good printability, and when cured using the same curing step as in Example 1, a good pattern consisting of a polyimide film was obtained.

Comparative Example 1 695.6 g of NMP was weighed into a Mitsuro 21 flask. To this, 120.1 g of DAli was added at 5D° C. while stirring the solvent, and completely dissolved. When DAg is completely dissolved, 124.3 g of PMDA is added little by little and reacted at 50°C for 50 minutes. Thereafter, the temperature was raised to 80°C and the reaction was continued for an additional 50 minutes. Thereafter, the temperature was raised to 150°C, and a reaction was carried out at 150°C for 20 hours to precipitate polyimide powder.

This powder was filtered through a 3G glass filter and heated to 150°C.
Vacuum drying was carried out for one day and night to create polyimide powder.

Separately, 695.6 g of NMP was placed in a Mitsuro flask (No. 21), and 94.3 g of DAE was added thereto at 70° C. until completely dissolved. After DARE is completely dissolved, add BTDA1 under stirring.
59.3g was added and reacted for 2 hours to produce polyamic acid. The polyimide powder prepared earlier was added little by little to the resulting polyamic acid solution to prepare a varnish. When this varnish was observed using a microscope image processing analyzer, a large number of secondary aggregates were observed, indicating that the powder was not uniformly dispersed in the binder.When screen printing was performed using this varnish, the varnish screen "Shedding" was poor, making it impossible to print multiple times, and secondary aggregates were observed here and there in the coating film obtained, making it impossible to obtain a uniform coating film.

Patent Applicant Higashi Shikaisha Co., Ltd. 12-

Claims (1)

[Claims] A tetraorganic carboxylic acid anhydride and a diamine are reacted in a solvent, and the polyimide precursor bath solution is heated at an imide ring-closing degree to precipitate polyimide powder, and in a suspension of the obtained polyimide powder. A method for producing a polyimide varnish, which comprises reacting a tetraorganic carboxylic acid anhydride and a diamine to form a polyimide precursor.