JPH01292035A - Moldable polyimide resin and molded article - Google Patents

Abstract

PURPOSE: To obtain the titled tough resin with for a molding granule of a large surface area by reacting an organic diamine with tetracarboxylic acid dianhydrate in a solvent, adjusting a density after the reaction, mixing a polymer solution with the nonsolvent and stirring it.

CONSTITUTION: The organic diamine and the tetracarboxylic acid dianhydrate of a formula I (R' is a bivalent residue having more than one 6-carbon ring, the rings are characterized by benzenoide unsaturation, a valence connection being not more than one is positioned on one of the cycles when more than two rings exist) is reacted in pH 0.8-10.0 solvent, the polymer density in the reaction liquid is kept to be 1-15% after that, the polymer solution is added by keeping that it contains the solvent where the proportions of the nonsolvent of the polymer and the nonsolvent with the original polymer solvent are equal to below 70% at the time of adding them and it is stirred so that the target resin being the solid particular shape which is provided with repeating units indicated by the formula II (RT is the quadrivalent residue of 6-carbon atom cycle which is characterized by benzenoide unsaturation, etc.), and is provided with the surface area being more than 20 m² per 1 g is obtained.

COPYRIGHT: (C)1989,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION Aromatic polyimide materials are generally produced by reacting a detracarboxylic dianhydride with an organic diamine to form a polyamic acid and then converting the polyamic acid to a polyimide. Techniques for the production of such polymers are described, for example, in US Pat.
Found in 88.

Endley's patent involves simultaneous conversion to polyamic acid and polyimide and precipitation of this polymer from solution. Another technique, previously suggested and exemplified in Example 7 of the Endley patent, is to first precipitate a polyamic acid;
It then involves converting the polyamic acid to polyimide by thermal or chemical means. This results in a resin with low crystallinity and low surface area. The process described in the Gall patent produces polyimides with high surface area and high crystallinity.

Polyimides are used industrially for a wide variety of applications.

For example, polyimides can be formed into tangible articles or incorporated into paint enamels. Other uses of such resins include applications in molded products (
molding applications), where polyimide in particulate form can be used in a variety of technologically demanding environments such as jet engines, business machinery, automotive parts, and a wide variety of industrial equipment. Processed into a structure. Such molded polyimide parts can withstand high temperatures and exhibit excellent bearing properties, good electrical properties and excellent creep resistance. However, continuing efforts are directed towards improving the mechanical properties of these resins, such as toughness, to enable their use in a wider range of high temperature environments.

SUMMARY OF THE INVENTION The present invention provides an improved polyimide molding resin that can be used in a molded configuration.
In particular, the present invention is characterized in that it has excellent stiffness in n). 00 [where R is a tetravalent residue having at least one six-carbon atom ring characterized by benzenoid unsaturation, and four carbonyl groups are directly linked to different carbon atoms in this residue, Six pairs of carbonyl groups are linked to adjacent carbon atoms in the six-membered benzenoid rings of the residues and R' is a divalent residue with at least one six-carbon atom ring (each term is , characterized by benzenoid unsaturation), and when at least two terms are present in R′,
In a solid particulate polyimide with no more than one valence bond located on any one of these terms and the particles have a surface area of more than 20 square meters per duram, this The solid particulate polyimide is improved in that the polyimide repeating units have less than two flexible bonds and are substantially amorphous.

The present invention also provides molded products of this polyimide.
a density of at least about 1.30 f/cc when molded to provide improved tensile elongation and tensile strength compared to the same polymer in crystalline form in the absence of fillers. show.

The present invention further provides the formula (1) [(2N-R'-NF12 (
where 11' is a divalent residue with at least one six-carbon atom (each term is characterized by benzenoid unsaturation), and when at least two rings are present in R', one No more valence bonds exist in any one of the rings than
and (2) at least one tetracarboxylic dianhydride and converting the resulting product into a polyimide. ,(,
) reacting the diamine and the dianhydride in a solvent having a - of about 0.8 to 10.0; ■) reducing the concentration of the solution resulting from the reaction of the tetracarboxylic acid and the dianhydride to about 1 to 15% polymer; (C) contacting the polymer solution with a non-solvent for the resulting polymer at a temperature of about 0 to 65°C; (d) adjusting the ratio of the non-solvent to the layer polymer solvent; (e) Stir the mixture of polymer solution and non-solvent so as to obtain a surface area in the polyimide polymer of greater than about 20 square meters per duram. The present invention provides a method for producing the solid particulate polyimide, which is improved by bringing the solution into close contact with a nonsolvent.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1.2 and 3 show that when immersed in a caustic soda solution,
1 is a graphical illustration of the performance of molding resins of the present invention compared to prior art resins.

FIG. 4 is a graphical comparison of the tensile strength of one inventive and prior art resin upon exposure to refluxing acetic acid.

Figures 5 and 6 are graphical comparisons of tensile strength and elongation of inventive and prior art resins containing various concentrations of graphite.

Figures 7 and 8 are representative X-ray diffraction curves for substantially amorphous and crystalline polyimides, respectively.

DETAILED DESCRIPTION OF THE INVENTION The reactants used to make the present polyimide compositions are those described in Gall, US Pat. No. 3,249,588, incorporated herein by reference.

In addition to the reactants specifically disclosed in the Gall patent, R2, R as described in the Gall patent.
3, as well as reactants in which R7 is partially or fully halogenated can be used.

The present invention provides for the production of rigid, normally crystalline polyimides of the type described in the Endrei patent, which, when produced under processing conditions as defined herein, exhibit high surface area and substantially amorphous properties. It is based on the discovery that it can be made in a particulate form characterized by a crystalline state. These particulate polyimides, when molded using high pressure according to conventional techniques, yield products characterized by significantly improved toughness.

Depending on the composition of polyimide, the tensile strength can be increased by 6 times (300%).
) can be improved. At the same time, the elongation at break of these products can be improved by a factor of 10 (1000%).

In contrast, polyimides that are not stiff or exhibit low crystallinity, when produced by conventional solution phase imidization, benefit little or no from the production of a substantially amorphous molding resin. Not at all.

The present invention, as noted above, is applicable to normally crystalline and rigid polyamides, ie polyimides whose repeating units have less than two flexible bonds. Such polyimides include rod-shaped polymers in which both the dianhydride and the diamine from which the polyimide is made are composed exclusively of phenylene rings or other rigid rings such as biphenyl or naphthyl groups. Relatively sparse polyimides can also be used in accordance with the present invention so long as the polyimide has fewer than two flexible bonds in the polyimide repeat units. Examples of such table flexible joins are -o-, -s-, -CH2-
, -E102-, -0(CF3)2-.

-(c=o)-, -0(0)-1JE(-1 or -c
(o)-o-.

Relative to Vera-substituted monomers, meta- or ortho-substituted aromatic diamines and dianhydrides also reduce crystallinity in the polymer. Such positional isomerism is therefore considered to be a suspended flexible bond in the context of the present invention.

The invention is applicable to polyimides as defined above which are normally crystalline. Crystalline is used in its common sense. That is, the X-ray diffraction scan obtained from the polymer is characterized by distinct peaks in the corner areas of the scan that are dominated by chain-to-chain interactions. These crystalline peaks are equatorial reflections (mirror coefficient hko for polymers where the chain axis of the polymer coincides with the C axis of the unit cell).

%CuK in corner areas with stronger equatorial reflections
- Generally between 10° and 35° 2-theta when observed by alpha radiation (α 15418 nm).

Polyimides are usually characterized by the presence of a well-defined mesodional peak (as discussed above, with a Miller coefficient of 001 or 002) at angles less than 10°2-theta, which indicates the absence of a well-defined peak. should not be considered contradictory. More specifically, 10° and 65°2-
The absence of a distinct peak in the region between theta can be tested by the absence of any distinct minima in this region other than the low and high angle limits of the broad amorphous peak. A sharp minimum is characterized by having a slope of zero or a first derivative where the curvature or second derivative is positive or upwardly concave. The scan for this test consists of a nickel filter or a monochromatic crystal and a characteristic copper emission
Obtained on a well-aligned reflective powder diffractometer using pulse height analysis set to pass 0% symmetrically. Similarly, substantially amorphous means
This is the lack of clear outlying peaks as discussed in .

Typical X-ray diffraction scans are shown in Figures 7 and 8, for substantially amorphous and crystalline polyimides, respectively. The crystalline scan in FIG. 8 shows distinct peaks 1. in the corner areas of the scan dominated by chain-on-chain interactions.
2. and 3 are shown. These peaks are not present in the corresponding scans in FIG.

Substantially amorphous crystalline properties are also indicated by a low crystallinity coefficient, which arises from crystalline and amorphous regions in the polymer powder, as derived from X-ray diffractometer scanning of the resin powder. The total interference intensity is the ratio of the interference intensity arising from the crystalline zone to 1% for a polyimide prepared from oxydianiline and pyromesotonic dianhydride, which has a substantially amorphous crystalline character.

Generally indicated by a crystallinity factor of about 15.

The production of the polymer includes reacting at least one tetracarboxylic dianhydride with at least one organic diamine as defined herein to obtain a polyamic acid. The polyamic acid is then precipitated from solution and then converted to polyimide by heating. Within this reaction sequence, careful control of reaction parameters is necessary to obtain the improved polyimide compositions of the present invention, which are characterized by high surface roughness and low crystallinity. Besides the structural requirements as listed above, the reaction parameters include:
Composition of polymer solvent solution: including polymer solution concentration; solvent solution to precipitation solution concentration: as well as agitation intensity in the precipitation environment.

In preparing the polyimide compositions of the present invention, the specific diamine reactant is generally first dissolved in a solvent. Solvents that can be used include organic solvents whose functional groups do not appreciably react with any of the reactants and exhibit about 8 to 10... The... of a solvent can be measured by dipping a piece of p)1 paper moistened with water in pure solvent. Such solvents include, for example, pyridine and eta-picoline. Pyridine has been found to be particularly satisfactory in the preparation of the polyimides of the present invention having high surface areas. Additionally, as long as the solvent mixture remains within the range of 8 to 10 as stated above, about 4
Up to .degree. weight percent of non-basic solvents such as dimethylacetamide (DMAO) or n-methylpyrrolidine (NMP) can be included. In cases where the insolubility of the polyamic acid in pyridine would cause premature precipitation of the low molecular weight polymer, inclusion of a relatively polar non-basic solvent may be preferred.

The amount of solvent is important in obtaining products with high surface area.

In particular, the solvent is such that:) the concentration of the polymeric reaction product of the amine and dianhydride is from about 1 to 15% by weight of the solution, preferably from about 1 to 15% by weight of the solution;
It should exist in such a way that it becomes 10%.

Generally, after dissolving the organic diamine in a suitable solvent and at the desired concentration, the dianhydride reactant is added to the reaction solution. Additional solvent can be used during addition of the dianhydride reactant so long as the final concentration of reaction product in solvent is about 1-15%. However, if desired, the dianhydride can be introduced before or simultaneously with the diamine.

The polyamic acid is precipitated by adding a non-solvent to the polyamic acid. Such non-solvents include, for example, acetone, ketone solutions or liquid hydrocarbons having at least 3 carbon atoms, such as n-octane, hexane, toluene, liquid pronocolon, cyclohexane, tetralin, chloroform, methylene chloride and trichlorotrichloride. It can be selected from halocarbons such as fluoroethane and esters such as ethyl acetate, aliphatic ethers such as diethyl ether, and alcohols such as methanol. Of these, acetone, toluene and trichlorotrifluoroethane have been found to be particularly satisfactory. Combinations of the above solvents can also be used. The choice of non-solvent will be apparent to those skilled in the art and will vary with each polymer composition.

Precipitation of polyamic acid should be carried out at a temperature of about 0-65°C. Temperatures of about 10° to 40° have been found to be particularly convenient.

The ratio at which the polymer solution and non-solvent are contacted is an important factor in obtaining the high surface area polyimide of the present invention. Specifically, the solvent and non-solvent together should contain no more than about 70% solvent.

After conversion, the solvent and non-solvent are brought into intimate contact to obtain a surface area in the final polyimide of greater than about 20 m2/f.

Generally, more vigorous agitation results in higher surface area.

After precipitating the polyamic acid from the initial reaction solution, the polyamic acid is preferably washed with a non-solvent to remove the solvent. Typically, washing is carried out at external conditions with an additional amount of precipitation liquid, generally at least about three times the volume of the polyamic acid. Unless residual solvent is substantially completely removed.

Resulting in low surface area in the final resin.

After washing the precipitated polyamic acid, about 190 to 200
It can be converted to polyimide by heating to a temperature of 150-180°C, preferably about 150-180°C. 200℃
Temperatures above 100° C. result in relatively low toughness in the molded article, while curing temperatures below about 100° C. result in inadequate conversion of the polyamic acid to polyimide. Typically, the conversion of polyamic acid to f IJ imide is carried out in an inert atmosphere, such as nitrogen, to prevent hydrolytic and/or oxidative degradation of the resin.

Depending on the particle size resulting from precipitation of the polyamic acid from the reaction solution, the polyimide particles can be further modified, for example by suitable grinding techniques, to obtain the desired particle size for handling and subsequent shaping. can. Particulate polyimide can be formed under high pressure into a wide variety of structures. It has been found convenient to form the particulate polyimide at an ambient temperature at a pressure of about so,ooo to 100,000 psi, and then sinter at an elevated temperature, e.g., about 400<0>C for about 5 hours. These molding conditions typically result in a mold density of at least about 1.30 f/cc.

The resulting molded polyimide retains its substantially amorphous character. Polyimides made from oxydianiline (CLIA) and pyromellitic dianhydride (PMDA) have a density of less than about 15, for example, when molded to a density of at least about 1.50 f/cc, as determined by X-ray diffraction. indicates the crystallinity coefficient of These molded polyimides are E-
Using the tensile par described in Figure 17 of 8, ASTM
Exhibits a tensile elongation of greater than about 20% as measured by Procedure D-638. Moreover, the tensile strength is at least j7k
It is psi. The present polyimide compositions are therefore particularly well suited for structural components when significant resistance to high temperatures is required, combined with good toughness. Additionally, the dihydric composition exhibits improved resistance to caustic soda and acetic acid.

Fillers, particularly carbonaceous fillers such as graphite, can also be used in the present polyimides to improve wear and friction properties while retaining improved tensile properties to a large extent.

For example, incorporation of about 2 to 10 percent graphite in polyimides made from ODA and PMDA results in moldings having an elongation greater than about 189 g and a tensile strength greater than about 11.5 kpsi. Incorporation of about 10-50% graphite results in a mold with an elongation greater than 49 g and a tensile strength greater than about 7' kpsi. Graphite or other fillers should be added before precipitation.

The outstanding performance of this product is not completely understood, but is believed to be a function of its high surface area, combined with its low crystallinity. Previous FoIJ imide moldable resins are characterized by either high surface area and high crystallinity or low surface area and low crystallinity.

The invention is further illustrated by the following specific examples, in which example parts and percentages are by weight unless otherwise specified.

The specific surface area of the resin is the number of square meters of surface per resin durum, as measured by nitrogen absorption techniques. In these examples, measurements of this resin parameter were carried out by Instrument Publishing Co.
“5 scientific and engineering” published in 1942
industrial glassblovingand
Laboratory Techniques” x
Standard B as described by Pal and Anhorn in Chapter
l! :T operation was used.

Example 1 and Comparative Example A In Example 1, 4.4'diaminodiphenyl ether (ODA) 6 was added to a dry nitrogen blanket type reaction vessel.
I prepared 0 copies. The ODA was flushed into the flask during the addition of 1500 parts of pyridine with stirring. After ODA is dissolved, pyromellitic dianhydride (PMDA) 64
．． 5f was completely flushed into the system in stages with an additional 150 parts of pyridine.

After stirring for 1 hour at room temperature, the intrinsic viscosity was determined to be 1.05 and the solution concentration was 70%.

This solution of boriamic acid in pyridine was pumped at a rate of 65 parts/min into a countercurrent precipitator with a stirring blade enclosed in a glass envelope with two inflows and one outflow. The acetone flow to the precipitator was controlled at 70 parts/min using a valve and rotometer, and 4 parts/min was added to the effluent slurry stream.
A pyridine concentration of 6% was obtained. The reaction and precipitation were carried out at room temperature. The slurry was filtered in a medium porosity filter. The mother liquor was removed from the filter cake through drainage washing using about 1600 parts of acetone. This acetone wet filter cake was heated to 160°C and 25°C in a nitrogen stream.
Drying at 1F If vacuum for 16 hours converted the polyamic acid to polyimide. This polyimide resin is %3o
Grind in a mill using a mesh sieve.

Comparative Example A was prepared from the same reactants but simultaneously precipitated and converted from polyamic acid to polyimide substantially in accordance with the procedure set forth in Gol US Pat. No. 3,249,588 Example 3.

This resin was tested according to ASTM Procedure D-638 using the tensile parr described in Figure 17 of E-8. Tensile par is 100.0OOT from copolyimirr
I01 and formed directly in a room temperature trap and sintered at 405°C for 3 hours. Pars were formed using the procedure described by Jordan, US Pat. No. 3,413,394.

Table I shows the properties of the resins and molded articles for the resins of Example 1 and Comparative Example A.

Table 1 Physical property examples Surface area m2/ta ゛ 60 4゜Crystallinity coefficient 30 12 Infrared imide% 9
0 9゜Appearance is density 9/Cl-0,2[)
015 type shrinkage, shrinkage X 2.0-2.5
2.5-3.5 tensile strength kpe111.0
140 Elongation (DMAC)
A freshly prepared solution of 12.01 parts of highly purified 4,4'-diaminodiphenyl ether in 118 parts was used to prepare polyamic acid. This solution was prepared, using vigorous stirring, with 1 part of pyromellitic dianhydride in 65 parts of DMACl.
Added quickly to 2.83 parts of freshly prepared solution. D
Transfer of one solution to the other was completed using 47 parts of MA0. These solutions were prepared in a nitrogen atmosphere. The polyamic acid solution obtained after the reaction was completed had an intrinsic viscosity of 1.12. DM a part of this polyamic acid solution
It was diluted to twice its volume with Ac and precipitated by high shear stirring in a mixer filled with toluene. Large volumes of toluene were required, yielding precipitation to solution ratios greater than 10 to 1. Excess solvent was decanted and the precipitate was washed with fresh toluene in a blender. This precipitate was heated to 100°C in a nitrogen stream.
Heat and dry for one night and increase the temperature to 325°C for 8 hours.

It was formed into a tensile bar at 100.0 OOpBi and room temperature and sintered at 1.405° C. for 3 hours.

The tensile properties were evaluated and found to exhibit a tensile strength of 51) kpsi and an elongation of 6.4%.

Example 2 and Comparative Example C In Example 2, 7.
A 25% by weight solution of polyamic acid in pyridine was prepared. 100 parts of this polymer solution were fed at 20 parts per minute into 150 parts of trichlorotrifluoroethane in a high shear mixer operated at room temperature. The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with trichlorotrifluoroethane. The filter cake was dried for 16 hours at 160'C in a 25 inch mercury vacuum under a nitrogen purge. The dried resin was ground through a 30 mesh sieve. This dried resin was processed into tensile shears according to ASTM procedure-638 using a tensile parr as described in FIG. 17 of E-6. Par is room temperature and 100
,000 psi forming pressure and free sintered at 405° C. for 3 hours under nitrogen purge/atmospheric pressure. The tensile strength and elongation of this par are h 12-okp
s i and 20%.

In Comparative Example C, Gal's US% allowance was 3,249,58
8. Tensile shivers from polyimide resin prepared according to the procedure of Example 3 were similarly molded and sintered at the same time. Their par has a tensile strength of 1α6kpei and 7,96'
It has an elongation of mourning. The crystallinity coefficient of Comparative Example C is 27.1
Met.

Example 6 The procedure of Example 2 was repeated, except that trichlorotrifluorethane was replaced with acetone as the precipitant solution. 1.1! tensile bar from this resin together with ζ- from Example 1!
A, exhibited a tensile strength of 1 kpsi and an elongation of 26%.

The X-ray diffraction crystallinity coefficient of this resin was measured and found to be 1'5.9, as opposed to 27.1 for Control Example O.

Example 4 and Comparative Example D The procedure of Example 3 was repeated except that the concentration of the polyamic acid-pyridine solution was 3.5% by weight and contained 15% by weight graphite based on the polymer. repeated. The graphite was Dickson type 200-09 with an average particle size of 5 microns. This resin has an X of 12.0
It had a linear diffraction crystallinity coefficient. In the comparative example,
Comparative Example A, but with 5 micron graphite 15x1
A polyimide resin containing as much as 1% was tested and had an X-ray diffraction crystallinity coefficient of 32. The resin of Example 4 was 11.
It had a tensile strength elongation of 2 kpai and 18%.

The tensile strength elongation of the control resin was 10, 1 kpsi and 8
%Met.

Example 5 and Comparative Example E Example 3 except that pyridine was replaced with beta-picoline
and Comparative Example A was repeated. Polymer solution at 250 m/min
The mixture was fed into a blender at the same time. Resin is 12.6k
It had a tensile strength of psi and an elongation of 24%. In Comparative Example E, the control resin had a tensile strength of 11.6 kpsi and an elongation of 9%.

The following examples are based on the operation of a continuous precipitation system using a polymer solution, as described in U.S. Pat. No. 3,249,588 to Gall. The polyamic acid solution is delivered to a precipitation vessel, which is also supplied with a continuous flow of non-solvent. The resulting slurry is then filtered and the filter cake is washed. The resulting polyamide is then converted to polyimide by drying in a vacuum tray drying mold at 170° C. and then ground and passed through a 30 mesh sieve.

The following series of examples shows the response of the properties of this resin to the concentration of pyridine in the precipitation environment.

Example 6 In a continuous precipitation system, 7% by weight of polyamic acid on the surface
Pyridine solution at 55 parts per minute and acetone feed rate at 50
It was supplied by the department. The concentration of pyridine in the precipitation environment is 51
%, the temperature was nominally 25° C., and the stirrer was operated at maximum speed.

The precipitated polymer was filtered, washed on the surface with 3 cake volumes of acetone, and dried at 175° C. in a 25 inch mercury vacuum.
Dry for 6-20 hours. The dried resin was milled through a 30 mesh sieve. The resin has a crystallinity coefficient of 12.5, a surface area of 46,3 m2/9, and a
．． It had a tensile strength/elongation of 9 kpsi/23%. The control resin prepared as in Comparative Example A had a crystallinity coefficient of 27, a surface area of 56.8 m2/9, and a surface area of 11.6 k
It had a tensile strength of psi and an elongation of 95%.

The infrared spectrum of this resin is the absorbance ratio of the band of 725cIR-' to the hand of i1027c11 and about 3.
Assuming an absorbance ratio of 10 represents 100% imidization)
showed a degree of imidization of 89%. The control resin was 100
% imidization degree.

Example 7 Example 6 was repeated except that the acetone rate was 80 parts per minute and the concentration of pyridine in the precipitation environment was 39%. This resin has an X-ray diffraction crystallinity coefficient of 99, 55
．． Surface area of 3 m2/9, line K 13.3 kpsi,
It had a tensile strength of 24% and an elongation of 24%. Example 8 Example 6 was repeated except that the acetone rate was 42 parts per minute and the concentration of pyridine in the precipitation environment was 55%. This resin has a crystallinity coefficient of 12.8, 56.4fn
It had a surface area of 2/9 and a tensile strength of 13.1 kpsi and an elongation of 25%.

The infrared spectrum of this resin showed 92% imide.

Example 9 Example 6 was repeated except that the acetone rate was 34 parts per minute and the concentration of pyridine in the precipitation environment was 60%. This resin has an X-ray diffraction crystallinity coefficient of 12.8,
32.6 fi2/litre surface area and 12.7 k each
psi and a tensile strength and elongation of 28%.

Example 10 Example 6 was repeated except that the acetone rate was 28 parts per minute and the concentration of pyridine in the precipitation environment was 65%. This resin is 14.2 kpai and 29%, respectively.
It had a tensile strength of 24% and an elongation of 24%.

Example 11 Example 6 was repeated except that the acetone rate was 28 parts per minute and the concentration of pyridine in the precipitation environment was 70%. This resin has an X-ray diffraction crystallinity coefficient of 118, 22.
It had a surface area of 7WL2/9 and a tensile strength and elongation of 111 kpsi and 20%.

Comparative Example F Example 6 was repeated except that the precipitation environment minor solvent concentration was 75% pyridine. Acetone supply rate is 1 per minute
There were 8 parts. This resin has a crystallinity coefficient of 10.5, 1
1.7 m2/9 surface area and 10.6 kpsi each
and a tensile strength and elongation of 19%.

In Comparative Examples G-H, polyimide products in solvent were produced having a pH lower than about 8-10.

Comparative Example G 99% by weight dimethylacetamide with a pH of about 7
of PAA were added to 1735 parts of toluene in a high shear mixer operated at room temperature. The slurry was filtered, washed with 3 cake volumes of toluene, and dried at 175° C. for 18 hours in a 25 inch mercury vacuum under a stream of nitrogen.

The dried resin was ground through a 30 mesh sieve.

The resin had a crystallinity coefficient of 14.8, a surface area of 12.6 2/9, and a tensile strength and elongation of 10.0 kpsi and 5.3%, respectively.

Comparative Example H Comparative Example G was repeated, except that the FAA/DMAc solution was 5.5 wt-0 PAA. The crystallinity coefficient of the obtained resin is 12.5, the surface area is 11.9°2/9, and the tensile strength and elongation are 7 and 6k, respectively.
psi and 3.5%.

Examples 12-15 and Comparative Examples 1-L In Examples 12-15 and Comparative Examples 1-L, the tensile strength was determined according to the present invention and according to Gall, U.S. Patent No. 5.249, respectively.
．． 588, was formed directly at 100,000 psi and room temperature from the resin produced by the simultaneous conversion and precipitation shown in Example 6. The tensile strength and elongation responses to temperature were measured for both resins as shown in Table 1 below.

Table ■ 12 405 14.1/22 I 405 11.2/9.5 13 380 13.3/25 J 3Q0 1o, 5/8.1 14 350 12.9/25 K 350 9.215.3 15 300 11.6/22 L 300 4.3/1.5 Examples 16-17 and Comparative Example M From the same resin used in Examples 12-15 and Comparative Example E-L at a standard pressure of 100,000 psi. A.S.
TM-E8 tensile pars were directly formed.

Pars from both resins were sintered at 405°C for 3 hours.

In Example 17, another set of pars formed from the resin of the invention was sintered at 300° C. for 3 hours. These pars were immersed in a 1% caustic soda solution at 50°C. Figures 1 and 2 show the rapid weight gain of the par during the first two days of S dew, followed by the rapid loss of weight as the par softens and loses material at the surface.

The par of Example 16 gains weight at a much slower rate and exhibits superior tensile strength. The tensile strength after exposure is shown in Figure 5 for Example 16 and Comparative Example MK. The resins of the present invention lose tensile strength relatively slowly.

Example 18 and Comparative Example N Example 16 and Comparative Example M except that the tensile pars were exposed to a refluxing (102-103°C) 15% aqueous acetic acid environment.
The operation was repeated. FIG. 4 shows the significant tensile strength retention of pars made from the present resin compared to the comparative pars after 41 days of dew.

The following examples illustrate the properties of the graphite-filled resins of the present invention in comparison to prior art graphite-filled resins.

Example 19 Polyimide was produced using the continuous precipitation procedure of Example 5. Lonza KS-5 with an average particle size of 5 microns
6.5 wt% FAA containing 10 wt% graphite (based on the weight of the polyimide resin to be formed)
/pyridine solution was fed at 55 parts/min. For a pyridine concentration of 60% by weight in the precipitation environment, acetone was fed at 35 parts/min. The slurry was filtered into a 4 liter glass fritted funnel and washed with 3 cake volumes of acetone. Filter cake, 25"H under nitrogen purge
Tray dried at 170"C in 2 vacuums. The dried resin was milled in a Willey mill through a 6o mesh sieve. The resin had a crystallinity coefficient of 12.9, a crystallinity coefficient of 26.5
It had a surface area of 1n2/9 and a tensile strength and elongation of 12.3 kpsi and 25%, respectively.

Example 20 Example 19 was repeated except that 20% graphite was included in the PAA/pyridine solution. This resin had a crystallinity coefficient of 13.8, a surface area of 25.0 m2/9, and a tensile strength and elongation of 10.7 kpsi and 19%, respectively.

Example 21 Example 19 was repeated except that 40 wt.ffi% graphite was included in the PAA/pyridine solution. This resin had a crystallinity coefficient of 15.1, a surface area of 20.4 m2/9, and a tensile strength and elongation of 8.8 kpsi and 72%, respectively.

Example 22 Example 19 was repeated except that 30% by weight graphite was included in the FAA/pyridine solution. This resin had a crystallinity coefficient of 15.8, a surface area of 23.8 2/9, and a tensile strength and elongation of 9.2 kpsi and 12%, respectively.

Example 23 Example 19 was repeated except that 50% by weight graphite was included in the FAA/pyridine solution. This resin had a crystallinity coefficient of 16.8, a surface area of 24.2 m2/g, and a tensile strength and elongation of 8.2 kpai and 5.3%, respectively.

Comparative Examples 0 and P The operations of Examples 19-23 were repeated, except that the polyimide resin prepared according to Comparative Example A was used.

The graphite concentrations were 15% and 37%, respectively.

Comparative crystallinity coefficients and surface areas for the graphite-filled resins of Examples 19 to 23 and Comparative Examples 0 and P are shown in Table 2.

The tensile properties of the graphite-filled resins of the present invention compared to the graphite-filled resins prepared according to Comparative Examples O and P are shown in FIGS. 5 and 6.

Table ■ About graphite-filled polyimide resin 19
10 12.9 26.520 2
0 13.8 25.021 40
15.1 20.422 30
15.8 23.823 50
16.8 24.2P 37
55 60 In the following example, after precipitation of the polyamic acid from the reaction solution, the slurry was filtered in a fritted glass funnel. The filter cake was drain washed with about 3-5 cake volumes of 'non-solvent' to completely remove residual solvent. Otherwise, there will be a low surface area in the final resin. The filter cake is removed from the filter and dried, typically under 25 inches of mercury vacuum and a nitrogen purge at 160° C. for 16 to 24 hours. 200°C
Drying temperatures exceeding 100% result in a decrease in the toughness of the molded article. 3 to limit the maximum particle size to approximately 600 microns.
Grind or deagglomerate the dry resin in a Willie mill equipped with a 0 mesh sieve. The final resin and products molded from this resin are routinely characterized for tensile properties.

Relative X-ray crystallinity, specific gravity and surface area were measured as appropriate.

In all embodiments of the invention, the surface area is 20 f
n2/9, the polyimide was substantially amorphous.

Example 24 and Comparative Example Q - PMDA/PPD Example
24 DMAc 250- and pyridine 350- at 60°C
20.00 g of para-phenylenediamine was dissolved in -. Pyromellitic dianhydride 4 with washing liquid of 20 pyridine
0.159 was added to make a 9% polymer solution.

A solution with an intrinsic viscosity of 13 dl/9 (in D1wLAc) was obtained. The exotherm of polymerization brought the temperature of the solution to 78°C.

After stirring the solution for 2.75 hours at about 75°C, the solution was cooled to 65°C and precipitated into acetone in a 1 quart size blender operated at room temperature and medium speed. Approximately 400 μm of acetone was used for every 125 μm of polyamide acid solution. The precipitation is immediate and quantitative;
The resulting slurry was filtered and washed with acetone. The filter cake was dried for 30 hours at 160 °C and 25" mercury vacuum under nitrogen purge. The dried resin was ground through a 30 mesh sieve in a laboratory scale Willey mill. The dried resin was dried at room temperature and at 100" 000ps
Processed to tensile par (ASTM E8) at a forming pressure of i.

The molded density of par is 1.40 cum3. The tensile par was then free sintered at 405° C. for 3 hours under 1 atmosphere with a nitrogen purge. Par density is 1.4 after sintering
It increased to 794-. The tensile strength and elongation of these pars were 7.5 kpsi and 1%.

Comparative Example Q Para-phenylenediamine 7,607 was dissolved in DMAc 75- and pyridine 145-. This solution was heated at 60°C.
pyromellitic dianhydride (15.269 g) was added along with 20 g. of pyridine. Intrinsic viscosity 1.3 dl/liter (D
A 97% by weight polymer solution (in MAc) was obtained.

After stirring the solution for 60 minutes at 75 DEG C., the polyamic acid solution was added dropwise using an addition funnel to a flask containing 100 ml of pyridine and 50 mL of DMAc under reflux. After the addition of the polyamic acid solution was complete, the solution was refluxed for an additional 2.5 hours. The resulting suspension was filtered and washed with 5 cake volumes of acetone. The filter cake was dried for 30 hours at 150° C. and 25” mercury vacuum under nitrogen purge. The dried resin was dried in a Wiley mill for 30 hours.
Grind through a mesh sieve. This dried resin,
Processed to tensile par (ASTM 118) at room temperature and 100,000 psi forming pressure to a formed density of 1.4
I got a par of 597 an'. The tensile par was then free sintered at 405° C. for 3 hours under 1 atmosphere with a nitrogen purge. The resulting tensile par has a density of 1.492/cm
3, tensile strength and elongation are 3.2 kpsi and 0
．． It is 3%.

Comparative Examples R and S - PMDA/APB-133 Comparative Example
R At 69°C, 1,6-bis(3-
Aminophenoxy)benzene (APR-133) 1Z0
1 was dissolved. 12.639 ml of pyromellitic dianhydride was added along with a 20-ml wash of pyridine to create a 13.8% polymer solution. A solution with an intrinsic viscosity of 0.34 dt/9<in pyridine was obtained. The exotherm of polymerization brought the temperature of the solution to 84°C. Keep the solution at about 85°C for 3 hours,
It was then heated in refluxing pyridine (115°C) for 6.5 hours. The precipitate was washed three times with acetone and the filter cake was dried for 24 hours at 180°C and 25" mercury vacuum under a nitrogen purge. The dried resin was ground through a 30 mesh sieve in a laboratory scale Willey mill. The dry resin was processed into tensile par (ASTM B8) at room temperature and a forming pressure of 5,0 Opsi.The mold density of the par is 1.40 g/l knee.

The tensile par was then free sintered at 550 DEG C. for 6 hours under 1 atmosphere using a nitrogen gun. The tensile strength and elongation of these pars were 8.8 kpsi and 3.5%.

Comparative Example S Pyridine 170- to 1,3-bis(5-aminophenoxy)benzea (APB133) 17. ．． 04g was dissolved and the solution was cooled to 5°C. Add 12.729 ml of pyromellitic dianhydride together with 20 ml of pyridine washing solution,
．． An 8% polymer solution was made. Intrinsic viscosity 0.76dl
A solution of /li (in DMAC) was obtained.

The exotherm of polymerization brought the temperature of the solution to 26°C. The solution was kept at approximately 25°C for 2 hours. This polyamic acid solution was added dropwise to refluxing pyridine (115°C) containing 15-acetic anhydride. The resulting suspension was refluxed for a further 2 hours, then the precipitated polyimide was filtered and washed three times with acetone, and the filter cake was dried for 16 hours at 150° C. and 25" mercury vacuum under nitrogen purge. The dried resin was milled through a 30 mesh sieve in a laboratory scale Willie mill.The dried resin was heated at room temperature and 5.000 psi
Processed to tensile par (ASTM E8) at a forming pressure of . The tensile par was then free sintered at 650° C. for 3 hours under 1 atmosphere with a nitrogen purge. The tensile strength and elongation of these pars are 13.2 kpsi and 5.7
%Met.

Example 25 and Comparative Example T - BPDA/PPD Example
25 DMAclOo- and pyridine 130- at 60°C
7.829 g of para-phenylenediamine was dissolved in the solution. 21.179 of 3.3',4.4'-biphenyltetracarboxylic dianhydride was added along with the wash of pyridine 20 to form a 10.8% polymer solution.

A solution with an intrinsic viscosity of 1.11 dl/g (in DMAc) was obtained.

The exotherm of polymerization brought the temperature of the solution to 74°C. The temperature of the solution was maintained at about 75° C. for 4 hours, and the solution was cooled to 65° C. and precipitated into acetone in a 1 quart size blender operated at room temperature and medium speed. Approximately 400 d of acetone was used for every 125 ml of polyamic acid solution. The precipitation was immediate, timely and quantitative, and the resulting slurry was filtered and washed with acetone. The filter cake was heated at 160° C. under nitrogen/ξ-di and 25” of mercury vacuum.
It was dried for 6 hours. The dry resin was ground through a 30 mesh sieve in a laboratory scale Wiley mill. This dry resin was processed into tensile parr (Allll'l'M E8) at room temperature and a forming pressure of 100.000 psi to obtain a parr with a density of 1.3194-. This tensile parr was then heated at 380° C. under 1 atm with a nitrogen purge.
Time-free sintering. The tensile par obtained was i, 419.
It has a density of 13 and a tensile strength and elongation of 20.9 respectively.
kpsi and 4.3%.

The above polyamic acid solution is (a) in ethyl acetate and (b)
The above procedure was repeated, except that the precipitation was in methylene chloride. Tensile strength/elongation is 16.6/2 in case (a)
．． 4, Mata et al.), it is 17.0/2.5.

Comparative Example T Para-phenylenediamine 7,579 was dissolved in DMAC 80 and pyridine 120. This solution was heated to 60°C, and 5.5', 4.4
'-Biphenyltetracarboxylic dianhydride 2 G, 7
Of was added to make an 11.8% polymer solution. The exotherm of polymerization raised the temperature of the solution to 73°C. 60℃
The solution was stirred for 0.5 h. This polyamic acid solution was added dropwise using an addition funnel to a flask containing pyridine 100- at reflux. After the polyamic acid solution addition was complete, the solution was refluxed for an additional 1.5 hours. The resulting suspension was filtered and washed with 5 cake volumes of acetone.

The filter cake was dried for 60 hours at 150° C. and 25” of mercury vacuum under nitrogen gas. The dried resin was
Milled through a 30 mesh sieve in a Willie mill. This dry resin was processed into tensile par (AS'rM E8) at room temperature and a forming pressure of 100,000 psi to a formed density of 1.34 L? , got a par of 5. This tensile parr was then subjected to 405°C under 1 atm using a nitrogen purge.
Free sintering was carried out at ℃ for 3 hours. The resulting tensile par exhibited a density of 1.41 t/cm' with a tensile strength and elongation of 6.9 Kpsi and 0.9 inches.

Example 26 and Comparative Example U - BPDA10DA Example
26 Oxydianiline 4α329 was dissolved in pyridine 820 d at 40°C. 3.3',4.4'-biphenyltetracarzenic dianhydride 5B, 95f was added along with a wash of 20 rrtl of pyridine to form a 10.6% polymer solution. A solution with an intrinsic viscosity of 1.16 di/f (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 55°C. The solution was heated at 70°C for 5.5 hours. The solution was then cooled to 65°C and precipitated into methylene chloride in a 1 quart size blender operated at room temperature and medium speed. Polyamic acid solution 150
Approximately 450 methylene chloride was used per d. The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with methylene chloride. The filter cake was dried for 15 hours at 160° C. and 25 # of mercury vacuum under nitrogen. The dry resin was ground through a 30 mesh sieve in a laboratory scale Wiley mill. This dry resin was processed into tensile pars (ASTM E8) at room temperature and 100,000 psi forming pressure to 1.2517 cm3.
I got a density of par. Next, this tensile parr was
Free sintering was carried out at 380° C. for 6 hours under 1 atm pressure. The tensile par obtained has a density of 1.30 f/α3 and a tensile strength and elongation of 17. I Kpsi and 21 Chi.

The above procedure was repeated, except that the precipitation was carried out in acetone; the result obtained was 17.0/21.

Comparative Example U 975v of oxydianiline was dissolved in 170rnl of pyridine. The solution was warmed to 70°C and 14.391 3.3',4.4'-biphenyltetracal I dianhydride was added along with 20 ytl of pyridine to give a 11.5% by weight polymer solution, i.e. A viscosity of 1.11 dt/l was obtained. The temperature of the solution rose to 81°C. The polyamic acid was stirred for 0.5 h at 80°C and then 100 m of pyridine was added under reflux.
Added dropwise to the flask containing J using an addition funnel. After the polyamic acid addition was complete, the solution was refluxed for an additional 1.5 hours. The resulting suspension was filtered and washed with 3 cake volumes of acetone. Filter cake under nitrogen purge
Dry for 15 hours at 50°C and 25" mercury vacuum.

The dry resin was ground through a 30 mesh sieve in a Willie mill. This dry resin was dried at room temperature and at 100.00
Tensile Par (ASTM) at 0 psi forming pressure
E8) to obtain a par with a molding density of 1.29 t/c-. This tensile par was then free sintered at 405° C. for 3 hours under 1 atmosphere using a nitrogen nozzle. The par obtained had a density of 1.32 t/l- with a tensile strength and elongation of 16.5 Kpsi and 6.8 inches.

Example 27 and Comparative Example V - ETDA/'PPD Example 27 22.519 para-phenylenediamine was dissolved in 750 WLl of pyridine at 60<0>C. Piri Kun 20
Adding 66.54f of 3.4.3',4'-benzophenonetetracardiphosphoric acid dianhydride together with the al washing solution,
A 3% IQ polymer solution was prepared. Intrinsic viscosity 0.55
A solution of a7t (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 74°C. The temperature of the solution was heated at 80C for 1.3 hours. The solution was cooled to about 60° C. and precipitated into methylene chloride in a 1 quart size blender operated at room temperature and medium speed. Approximately 4504 ml of methylene chloride was used for every 150 d of polyamic acid solution. The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with methylene chloride. The filter cake was dried for 15 hours at 160 DEG C. and a 25" mercury vacuum under a nitrogen blanket. The dried resin was ground through a 60 mesh sieve in a laboratory scale Willey mill.

This dry resin was processed into tensile par (ASTM E8) at room temperature and a forming pressure of 100,000 o8i. The tensile par was then free sintered at 380 DEG C. for 3 hours under 1 atmosphere of nitrogen gas. The resulting pars had a tensile strength and elongation of 19.3 Kpsi and 3.0 Kpsi, respectively.
5 showed regret.

The above procedure was repeated, except that the precipitation was carried out in (at ethyl acetate, (b) acetone and (C) a 1:1 mixture of hexane and ethyl acetate.

Tensile strength/elongation is 1 B, 3/3.2; 12, respectively.
．． 3/2.0 and 16.5/3.2.

Comparative Example V Pyridine 2252 and Raphenylenediamine 11.
06f was dissolved. Warm the solution to 62°C and add pyridine 2
3.4.3',4'-penzophenonetetracarzenic acid dianhydride 32.7 (l) was added with 0d, 14.4
A weight % polymer solution with an intrinsic viscosity of 0.74 dl/f was obtained. The temperature of the solution rose to 82°C.

Stir this polyamic acid for 0.5 hour at 80°C,
It was then added dropwise under reflux to a flask containing 100 d of pyridine. , N IJ After the addition of the amic acid solution was complete, the solution was refluxed for an additional 3 hours. The resulting suspension was filtered and washed with 5 cake volumes of acetone. The filter cake was dried for 15 hours at 180° C. and 25” of mercury vacuum under a nitrogen vacuum.

The dry resin was ground through a 30 mesh sieve in a Willie mill. This dry resin was heated at room temperature and at 100,000
Tensile par (ASTM) at forming pressure of Opai
E8). The tensile par was then free sintered at 380° C. for 3 hours under 1 atmosphere with a nitrogen purge. The obtained tensile strength and elongation were 4.9 Kps.
i and 0,5 chi are shown.

Comparative Example W -X -ETDA/MPD Comparative Example W 16.31 f of para-phenylenediamine was dissolved in 670- of pyridine at 60°C. Add 3.4.3',4'-benzophenonetetracarginic acid dianhydride 48.579 with the washing solution of pyridine 20-
% polymer solution was made. Intrinsic viscosity 0.34αn't
A solution of (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 81°C. The solution was stirred for 3.5 hours at 80°C. The solution was then cooled to about 40° C. and precipitated into methylene chloride in a 1 quart size blender operated at room temperature and medium speed. Approximately 400 ml of non-solvent methylene chloride was used for every 80 mm of polyamic acid solution. The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with methylene chloride.

The filter cake was dried for 15 hours at 160° C. under nitrogen, e-dielectric and 25” of mercury vacuum. The dried resin was
Milled through a 50 mesh sieve in a laboratory scale Willie mill. This dry resin was heated to room temperature and 40.0OO
Tensile par (ASTM E8) at a forming pressure of psi
). Next, this tensile par was free sintered at 60° C. for 3 hours under 1 atm using a nitrogen nozzle.

The density of par increased by 1.47 t/cm'K after that.

The resulting tensile pars were 20. IK
It showed a psi of 5.3%.

The non-solvent is (a) ethyl acetate, (b) acetone and (C)
The above procedure was repeated except that a 1:1 mixture of hexane and ethyl acetate was substituted. The tensile strength/elongation of parts molded from the corresponding resins are respectively (al 17. I K
psi, 5.4%; (bl 16.7 Kpsi
, 5.5 L12 and (c) 10.2 Kp8i
, 3.6 I regret it.

Comparative Example X 11.06f of pyridine 225dK meta-phenylenediamine was dissolved at 55°C. 32.969 of 3.4.3',4'-penzophenonetetracarzenic acid dianhydride was added along with a wash of 20d of pyridine to form a 14.5% polymer solution. A solution with an intrinsic viscosity of 0.35 tu7y (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 77°C. Stir this poly(amic acid)% acid solution for 0.5 h at 75°C and then add 100 d of pyridine under reflux.
was added dropwise to the flask containing. After the addition of the polyamic acid solution was complete, the solution was refluxed for an additional 3.5 hours. The resulting suspension was filtered and washed with 3 cake volumes of acetone.

The filter cake was dried at 150° C. and 25” mercury vacuum for 15 hours under a nitrogen purge. The dried resin was
Milled through a 30 mesh sieve in a Willie mill. This dry resin was processed into tensile materials (ASTM E8) at room temperature and a forming pressure of 100,000 psi. This par was then heated to 65°C under 1 atm using a nitrogen purge.
Free sintering was performed at 0° C. for 3 hours. The resulting tensile par shows a tensile strength and elongation of 16.8 Kpsi and 3.0%.

Comparative Examples Y and Z -BTDA10DA Comparative Example Y Pyridine 750 dK Oxydianiline 3 at 55°C
4.41f was dissolved. 54.95 f of 3.4.3',4'-penzophenonetetracarzenedic anhydride was added along with 20 rxl of pyridine wash solution to make a 10.4 liter polymer solution. A solution with an intrinsic viscosity of 0.60 dt/f (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 66°C. The temperature of the solution was heated to about 60° C. for 3 hours. The solution was then cooled to 60°C and precipitated into ethyl acetate in a 1 quart size blender operated at room temperature and medium speed. Approximately 400 tnl of ethyl acetate was used for every 15[]+tJ of polyamic acid solution.

The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with methylene chloride. The filter cake was heated at 160°C under nitrogen, R-di and mercury vacuum 25' for 15 minutes.
Dry for an hour. The dry resin was ground through a 30 mesh sieve in a laboratory scale Wiley mill. The dry resin was tensile per (ASTM E8) VC processed at room temperature and a forming pressure of 100,000 psi. This tensile parr was then heated to 35°C under 1 atm using a nitrogen purge.
Free sintering was performed at 0° C. for 3 hours. The resulting tensile pars were 17.9 Kpsi and 11.9 Kpsi for tensile strength and elongation, respectively.
It showed 5%.

Precipitate with (a) acetone (b) ethyl acetate and hexane 1
:2 mixture (c) except that it was carried out in methylene chloride.
Repeated the above operation. The results are 1Z5/12.7 respectively.
; 17.0/10.1 and 17.3/10.1.

Comparative Example 2 Pyridine 225flC Oxydianiline 16.85? was dissolved. This solution was heated to 59°C and pyridine 20-
3.4.3',4'-benzophenonetetracarginic acid dianhydride 26.9C1 was added with the washing liquid to obtain a polymer solution of 14.41 with an intrinsic viscosity of 0.82 dt/f. . An exotherm caused the temperature of the solution to rise to 75°C. The polyamic acid was stirred in solution for 0.75 hours at 75 DEG C. and then added dropwise under reflux to the flask containing 100-pyridine. After completing the addition of the amino acid solution, add the solution.3.
It was refluxed for 5 hours.

The resulting suspension was filtered and washed with 5 cake volumes of acetone. The filter cake was heated to 150°C under a nitrogen nozzle.
and dried in a 25" mercury vacuum for 15 hours. The dried resin was ground through a 60 mesh sieve in a Wiley mill. The dried resin was dried at room temperature and at 100,000 ps.
Processed to tensile par (ASTM E8) at a forming pressure of i. The molding density of par is 1.4097 cm3. This par was then heated to 380° C. under 1 atm using a nitrogen purge.
Free sintering was carried out at ℃ for 3 hours. The resulting tensile par shows a tensile strength and elongation of 20.9 Kpsi and 12.91.

Example 28 and Comparative Example - PMDA/MPD Example
28 10.05f of meta-phenylenediamine was dissolved in biridine 320- at 40°C. 20.172 ml of pyromellitic acid anhydride was added along with 20 d of pyridine wash to make an 8.3 t polymer solution.

A solution with an intrinsic viscosity Q of 7 dt/f (in pyridine) was obtained. The exotherm of polymerization brought the temperature of the solution to 62°C. 70℃
The temperature of the solution was heated for 40 minutes. Then add the solution to 6
Cooled to 5°C and precipitated into methylene chloride in a 1 quart size blender operated at room temperature and medium speed.

Approximately 400 methylene chloride for every 120 d of polyamic acid solution
- was used. The precipitation was immediate and quantitative, and the resulting slurry was filtered and washed with methylene chloride. The filter cake was heated at 160°C under nitrogen/ξ-di and 25°C in a mercury vacuum.
The dried resin was ground through a 30 mesh sieve in a laboratory scale Wiley mill.

This dry resin was processed into tensile pars (ASTM E8) at room temperature and a forming pressure of 100,000 psi to obtain pars with a density of t 25 Pi et al. The tensile par was then free sintered at 405° C. for 3 hours under 1 atmosphere with a nitrogen purge. The resulting tensile par shows a tensile strength and elongation of 17.3 Kpsi and 12.7 inches, respectively.

The above procedure was repeated, except that the precipitation was carried out in (a) anatone and (b) ethyl acetate. The results obtained are (a) 17.4 Kpsi/7.8% and 17.5 Kpsi/11.1%, respectively.

Comparative example: Pyridine 200 r! d! 10.12f of meta-phenylenediamine was dissolved in the solution. Keeping the solution at external temperature, add 20.47 t of pyromellitic dianhydride along with 20 rItl of pyridine.
12. with an intrinsic viscosity of 1.03 dt/l.
A 4% by weight polymer solution was obtained. The temperature of the solution rose to 55°C. The polyamic acid was stirred for 0.5 hour at 60° C. and then added dropwise using a 1 addition funnel to a flask containing 1001 Il of pyridine under reflux. After the addition of the polyamic acid solution was complete, the solution was refluxed for an additional 2.5 hours. The resulting suspension was filtered and washed with 3 cake volumes of acetone. The filter cake was dried for 15 hours at 150° C. and a 25” mercury vacuum under nitrogen A-di. The dried resin was ground through a 30 mesh sieve in a Wiley mill. The parr was processed into tensile parr (ASTM E8) at pressure. The parr was then processed to
Free sintering was carried out at 05° C. for 5 hours. The resulting tensile par shows a tensile strength and elongation of 5.3 Kpsi and a modulus of 1.2.

The properties of the polyimides obtained from Examples 24-28 and Comparative Example Q-AA are summarized in Table 2.

Tensile strength (Kpsi) 24/Q PMDA/PPD 7.5 3.2 +
134P%/S PMDA/APB 16.1 13
．． 2 +2225 BPDA/PPD 2
Q, 9 6.9 +20326 BPDA
loDA 17.1 16.5 +4W BTDA
/1) FD 19.3 4.9 +294Y/Z B
TDA/WD 20.1 1&8 +2028/AA
BTDAloDA 17.9 2 [L9 -14/A
A PMDAAAPD 17.3 5.3 +226 table ■ 1.00.3 +23346139 7.45.7 +3147 small 4.30.9 +378497 2tO'&8 +209 37 19
Shoko 5α5 +60067146 Yes 5.33.0 +77441o4 Small IT512.9-113287 No 12.7 11 +1055 -
Although the present invention has been described in detail on a plate, the present invention can be further summarized by the following embodiments.

1) A repeating unit represented by the following formula [where R is a tetravalent residue having at least one six-carbon atom ring characterized by benzenoid unsaturation, and four cartonyl groups are present in this residue. directly linked to different carbon atoms, six pairs of cardanyl groups are linked to adjacent carbon atoms in the six-membered benzenoid ring of this residue, and R' has at least one six-carbon atom ring. is a divalent residue (the 6 rings are characterized by benzenoid unsaturation) and when at least two rings are present in R',
In a solid particulate polyimide with not more than one valence bond located on any one of these rings and the particles having a surface area of more than 20 square meters per duram, this 2 priimide repeat units
The above solid particulate polyimide is improved in that it has a flexible bond of less than

2) having a density of at least about 1.3 (1/CC) and about 2
% filler and exhibiting a tensile elongation of greater than about 20% and a tensile strength of greater than about 12 Kpsi.

3) has a density of at least about 1.30 f/Cr;
The polyimide molded article of item 1) containing less than about 10% filler and exhibiting a tensile elongation greater than about 18 kpsi and a tensile strength greater than about 1t5 Kpsi.

4) The polyimide of 1) above, having a density of at least about 1.30 r/cc, containing less than about 50% filler, and exhibiting a tensile elongation of greater than about 4 Kpsi and a tensile strength of greater than about 7 Kpsi. molded products.

5) The molded article described in 2) above, wherein the filling agent is graphite.

6) (Formula 11 H2N-R'-NH2 [where R' is
A divalent residue having at least one 6-carbon atom ring (the 6-ring is characterized by benzenoid unsaturation), and when at least two rings are present in R', no more than one atom the valence bond is located on any one of the ring formations] (both one organic diamine, and (2)
A method for preparing a solid particulate polyimide by reaction of at least one tetracarzenic dianhydride and polyimide PK conversion of the resulting product, comprising: (a) in a solvent having a - of about 0.8 to 10.0; reacting the diamine and the dianhydride; (b) maintaining the concentration of the solution resulting from the reaction of the tetracardic acid and the dianhydride at a concentration of about 1 to 15 degrees of polymer; (C) reacting this at a temperature of about 0 to 65°C; contacting the polymer solution with a non-solvent for the resulting polymer; (d) maintaining the ratio of the non-solvent to the prototype coalescing solvent such that the solvent and non-solvent combined contain no more than about 70% solvent; (el Stir the mixture of the polymer solution and the non-solvent,
Bolimir larger than about 20 square meters per duram
7) Process for producing solid particulate polyimide, the improvement being that the non-solvent and this solution are intimately fused so as to obtain a surface texture in the polymer. 6), wherein the concentration of the solution is maintained at about 1-10% polymer.

8) The method described in 6) above, wherein the solvent is pyridine.

9) The method described in 6) above, wherein the solvent is beta-picoline.

6) The method according to 6) above, wherein the concentration of the solution resulting from the reaction of the tetracarzenic dianhydride and the organic diamine is less than about 10%.

11) The method according to 6) above, wherein the i-merged core liquid is contacted with a non-solvent at a temperature of about 10° to 40°C.

[Brief explanation of the drawing]

Figures 1.2 and 3 show that when immersed in caustic soda solution,
1 is a graphical illustration of the performance of molding resins of the present invention compared to prior art resins. FIG. 4 is a graphical comparison of the tensile strength of inventive and prior art resins upon exposure to refluxing acetic acid. Figures 5 and 6 are graphical comparisons of tensile strength and elongation of inventive and prior art resins containing various concentrations of graphite. Figures 7 and 8 are representative X-ray diffraction curves for substantially amorphous and crystalline polyimides, respectively. Patent Applicant: E.I. DuPont de Nemours & Company, Patent Attorney: Chiyoshi Ki 9. - 2 people outside of F 1z-plane cleanliness, 1 (no change in content) FIG, 1 6 cases 17 × example 16 0 control da IM Exposure work gojo (snake) FIG, 2 6 cases j7 × 1 row 16 0 contrast Example~1 0 2 4 6
a exposure ■ okai (snake) FjG, 3 0 10 20
KO 0 40 exposure Z sake (anatomy FIG, 4

Claims (1)

[Claims] 1) A repeating unit represented by the following formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [where R is a tetravalent residue having at least one 6-carbon atom ring characterized by benzenoid unsaturation] a group in which the four carbonyl groups are directly linked to different carbon atoms in the residue, and each pair of carbonyl groups is linked to an adjacent carbon atom in the six-membered benzenoid ring of the residue. , R' is a divalent residue having at least one six-carbon atom ring (each ring characterized by benzenoid unsaturation), and when at least two rings are present in R',
in a solid particulate polyimide having not more than one valence bond located on any one of these rings and the particles having a surface area of more than 20 square meters per gram; The solid particulate polyimide as described above, wherein the polyimide repeat unit has less than two flexible bonds and is substantially amorphous. 2) having a density of at least about 1.30 g/cc, about 2
2. The polyimide molded article of claim 1 containing less than % filler and exhibiting a tensile elongation greater than about 20% and a tensile strength greater than about 12 kpsi. 3) having a density of at least about 1.30 g/cc and about 1
The polyimide molded article of claim 1 containing less than 0% filler and exhibiting a tensile elongation greater than about 18% and a tensile strength greater than about 11.5 kpsi. 4) having a density of at least about 1.30 g/cc and about 5
The polyimide molded article of claim 1 containing less than 0% filler and exhibiting a tensile elongation greater than about 4% and a tensile strength greater than about 7 kpsi. 5) (1) Formula H2N-R'-NH_2 [wherein R' is a divalent residue having at least one 6-carbon atom ring (each ring is characterized by benzenoid unsaturation); when two rings are present in R', no more than one valence bond is located on any one of the rings;
) a process for preparing a solid particulate polyimide by reacting at least one tetracarboxylic dianhydride and converting the resulting product to a polyimide, comprising: (a) from about 0.8 to
reacting the diamine and dianhydride in a solvent having a pH of 10.0; (b) maintaining the concentration of the solution resulting from the reaction of the tetracarboxylic acid and dianhydride at about 1-15% polymer; (c) The polymer solution is contacted with a non-solvent for the resulting polymer at a temperature of about 0 to 65°C; (d) the ratio of the non-solvent to the original polymer solvent is about 70 for the combined solvent and non-solvent; (e) Stir the mixture of polymer solution and non-solvent to obtain a surface area in the polyimide polymer of greater than about 20 square meters per gram of the non-solvent and this solution. A method for producing the above-mentioned solid particulate polyimide, which is improved by bringing the polyimide into close contact with the solid particulate polyimide.