JPS59525B2 - Method for producing water-soluble organic polymers that can be electrodeposited - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION While it has been found that relatively thin films of resinous materials can be electrodeposited from aqueous solutions, it is not possible to ensure the desired range of film formation for a given polymer on a particular substrate. Nakatsuta.

In particular, it has been found that controlling and progressively increasing the thickness of electrodeposited film formations and obtaining precise consistency in the properties of polymeric films is beyond the capabilities of the art. . For most applications, especially those where multiple coatings must be used to obtain the desired film formation, film deposits are obtained by coating methods in which wire or other of material is passed through a solution, then possibly through a mold, a drying tower, and continuous movement takes place through the solution and finally into the drying tower for each successive formation. This method is a laborious and time-consuming method, and therefore there would be considerable economic savings, e.g., large structures to accommodate, if the coating method described above could be replaced by an electrodeposition method. And the economies gained by eliminating drying towers, which are expensive to operate and maintain, may be achieved. Also, with respect to solution-based coatings, only a relatively small amount of coating material can be deposited at a uniform thickness on the article as it passes through typical dip-and-drain solutions known in the coating art. has its own limitations. If electrodeposition were to become a meaningful practice in the industry, particularly in the field of applying insulation coatings on elements such as magnet wire, formulators would be able to apply a wide range of satisfactory resins, i.e., to deposits on conductors or other substrates. The formular must try to obtain a narrow range of molecular weight compositions that are relatively consistently obtained for the reactive moieties at the time of application, and the formulator may vary the thickness of the electrodeposited film from thin to thick films. must acquire the ability. Here, a polymer solution giving a thin electrodeposited coating is made into a dispersion by the introduction of an acid, and this dispersion is then compared without affecting the properties of the polymer in the ultimate cured film state. It has unexpectedly been found that electrodeposition can be performed to produce extremely thick coatings. Furthermore, once the ratio of bound COOH to NH3 is known and controlled, the desired film formation can be preselected for a given polymer, which can be formed in solution or in a well-dissolved thin film. It has been found that ranging from films to thick films in the case of dispersions, and intermediate film formation for intermediate ratios, this does not affect the known properties of the polymer in the cured state. Since molecular weight range plays a role in the performance properties of the cured polymer system, it is possible to incorporate the desired molecular weight range into the polymer before choosing electrodeposited film formation by simple selection of the COOH/NH3 ratio. It becomes possible. Furthermore, U.S. Patent No. 3
No. 663,510 (Application No. 823,108) discloses a method for improving polyamide coating materials in which a precursor material initially formulated in a 2/1 molar ratio of reactants has a slight molar excess. one or the other reactant in a ratio and the resulting product is then back titrated to a 1/1 molar ratio of reactants. In the present invention, either the dianhydride is back-added to the amine-terminated prepolyimide polymer or the aromatic diamine is back-added to the dianhydride-terminated prepolyimide polymer by the method described above. Thus any preselected desired molecular weight range is obtained. The product thus obtained can then be end-capped in the manner exemplified in US Pat. No. 3,652,500 (Application No. 851,835).

Polyorthoamic acid ammonium (ArrInO-Niu) synthesized with accurate viscosity and desired molecular weight range
Once we have obtained the correct ammonium stabilized aqueous solution of mpOlyOrthOamate), we proceed to adjust the PH of the system by adding a relatively weak acid such as formic acid, acetic acid or the like, and also adjust the intramolecular NH3// COOl) 7) By controlling the ratio, the solubility, and thus the ratio of the solution relative to the dispersed liquid phase of the polymer, can be determined, which is the It is a control condition for how thick a film can be electrodeposited on the substrate anode.

The main object of the present invention is to provide an improved method for producing an electrodepositable aqueous resin system that can be electrodeposited at a uniform rate onto a metal substrate to a uniform thickness of a preselected amount. . Another object of the present invention is to provide an improved method for formulating stable aqueous systems, preferably solutions, of resins whose molecular weight composition can be easily controlled, and whose composition can be dictated by the pH. It is possible to determine the thickness of a film electrodeposited on a metal substrate or the like by varying it with respect to a fixed (acid + anion)/base cation equivalence ratio.

Other objects and features of the invention will become apparent from the following description, which proceeds with reference to the accompanying drawings.

In general, resins that are soluble in aqueous ammonia are those that are stable in aqueous solution and that can be adjusted by a certain (acid + anion)/base cation equivalence ratio and dictated by the pH. It can be used in the present invention as long as it is soluble in. The inventors have found that, in general, the ratio of resin in the solution phase to resin in the dispersion or suspension phase has a decisive effect on the electrodepositability of the material. Most of the following examples
Although directed to polyimide insulating coated enamels, it should be understood that the principles of the invention are equally applicable to acrylic, polyester, alkyd, epoxy, cellulose, oleoresin enamels, and the like.

Examples of resins exemplifying the present invention are as follows.These resins are not intended to limit the present invention.

1. Polyimide Prepolymer System This resin system is derived from repeating units with pendant reactive carboxylic acid groups that can react with nitrogen bases to render the polymer water-soluble, and forms the polymer into a two-phase dispersion. and later acidified to transform into a soluble phase.

The resin system is derived from the following general formula and is then reacted with a nitrogen base to make it water soluble. Specific examples of resin systems include the following 3, 3',
A T monomonium salt of a condensation polymer of 4,4'-benzophenonetetracarboxylic dianhydride and 4,4'-methylene dianiline is used. 2. Polyester-based This resin system is derived from repeating units with pendant reactive carboxylic acid groups that can react with nitrogen bases to render the polymer water-soluble, and the polymer can be dissolved in a two-phase dispersion and an aqueous phase. It is later acidified to convert it to

This resin system can be constructed using difunctional and, in special cases, trifunctional reactants to form a low to medium molecular weight system, or as a cross-linking system. In special cases, a polycarboxylic acid reactant is used to form the general formula, which is then reacted with a nitrogen base to render it water-soluble.

In particular, examples of this resin system include ammonium condensation polymers of ethylene glycol (2 moles), dimethyl terephthalate (3 moles) and glycerin (1 mole) (sometimes reacted with pyromellitic dianhydride). salt is used. 3. Polyesterimide-based This resin system is derived from repeating units with pendant reactive carboxylic acid groups that can react with nitrogen bases to render the polymer water soluble; It is later acidified to convert it into a dispersion and a soluble phase.

This resin system can be constructed using difunctional reactants to form a linear molecular weight system, or as the following general formula to form a low molecular weight, cross-linking system: Using a functional reactant, the following general formula is derived, which is then reacted with a nitrogen base to make it water-soluble.

In particular, examples of this resin system include the reaction product of ethylene glycol (2 moles), terephthalic acid (1 mole), 2 moles of trimellitic anhydride, and 1 mole of 4,4'-methylenedianiline. The ammonium salt of a condensation polymer of (2 mol) and trishydroxyethyl isocyanurate (1 mol), sometimes reacted with biromellitic dianhydride, is used. 4. Head-to-Head Polyacrylic This resin system is derived from repeating units with pendant reactive carboxylic acid groups that can react with nitrogen bases to render the polymer water-soluble; dispersion and later acidification to convert it into a soluble phase.

This resin system is derived from a polyethylene chain having essentially ethylene monomaleic anhydride repeating units, which is subsequently reacted to form a half-ester mono-semi-acid moiety, as follows: ,
This is reacted with a nitrogen base to make it water soluble.

In particular, as an example of this resin system, the following ammonium salt of a half ester of an ethylene/maleic acid copolymer is used. Other polyacids such as trimellitic acid, phthalic acid, etc.2. and 4. It can be used instead of pyromellitic acid in and it can be selected depending on the product.

Referring to FIG. 1 and considering a polyimide prepolymer, first the precursor BMB is
2 moles of tetracarboxylic dianhydride (19
A precursor molecule is produced consisting of the reaction product of 1 mole of diamine and 1 mole of diamine.

This reaction can be expressed as follows. 2B+M
→ BMB As a specific reaction product and specific reactant, the aromatic dianhydride consists of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BPDA) with the formula .

The aromatic diamine consists of 4,4'-methylene dianiline (MDA) having the formula:

These two substances are 2 parts BPDA and 1 part MD.
When taken together in the molar ratio of A, the precursor BMB has the following formula:
form. The precursor, known as BMB, can be partially imidized before ``zipping up'' the stable precursor units, which results in the addition of M, which is a dry solution consisting of N-methylpyrrolid. This is accomplished in a solvent under dry nitrogen, preferably at a temperature below 50°C. Adding a slight excess of M ensures that terminal amine groups are obtained, and the reaction can be generally expressed as: This can be expressed by the following equation.

Once the specific viscosity and molecular weight of the prepolyimide has been optimized for the requirements of the desired product, the polyimide prepolymer can be prepared with a certain (acid + anion)/base cation appropriate for the particular polymer system. Water can be reduced by creating a favorable equivalence ratio of .

A volatile base material that can be used for certain purposes is ammonium hydroxide, which converts the prepolymer into the ammonium salt of polyorthoamic acid, thus forming repeating units of the formula:

The molecular weight of water-soluble materials is typically greater than 76,000.

The preselected range of molecular weights is tracked indirectly by measuring intrinsic viscosity. BMB<7) The precursor is prepared and then this BMB is added to an approximately 1.6% molar excess of M.
and then back-titrated with B to the desired molecular weight range that can be narrowly determined and then end-capped with M. After obtaining the specified desired molecular weight range (and the desired degree of imidization to control the viscosity of the solution), the material for electrodeposition is prepared.

Qualitatively, the relationship is that the polymer is made to be relatively insoluble as a dispersion for thick films to be electrodeposited.

The dispersion was made by adjusting the NH3/COOH ratio to 0/1 and the pH close to 3.5-4.06 and for thinner films the NH3/COOH ratio was 1. /1 to bring the pH closer to 3.5 to 4.0.

The relationship between application, thickness and molecular weight can be summarized as follows.

The advantage of low molecular weight products is their low viscosity and relative ease of handling.

The specific combination of thickness and molecular weight for a particular coating is
The suggested uses set forth in Table 1 under heading 1, ``Uses'' are determined accordingly.

However, generally speaking, low molecular weight and small thickness coatings are provided when relatively inflexible and when high temperature requirements such as those found in kitchen appliances are involved. In high molecular weight ranges and low thickness films, there are requirements for flexibility and integrity in the flexed state, which, along with substantial adhesion and electrically insulating properties, for high molecular weight and low thickness films. This shows its use as an insulating coating for net wires. Referring to Figure 3, after obtaining the desired molecular weight in the manner described above, the PH is determined by passing a relatively weak volatile acid other than carbonic acid into the solution, such as acetic acid, formic acid or the like. and constant (
The equivalent ratio of acid (ten acid anions)/base cations is PH9-10.
equivalent to 1/1 or 0.7/1.0 depending on the polymer system
The ratio is varied from some conveniently obtained ratio, which can range from .

Thus, by continuously adding large amounts of acid, the relationships set forth in the following table are obtained, which are taken from the polyimide-type polymers of the following examples. For optimal results, the pH of the electrodeposited dispersion should be PH3. O ~ about PH6.5
It was found that the maximum benefit of the present invention can be obtained within this range.

It has been found that above this range the dispersion is no longer suitable and no improvement in coating thickness can be obtained for a given amount of coating resin used compared to the results when operating within this range. Although dispersions are generally stable below this range, the acidic conditions created are generally undesirable for many applications, such as for use with copper and iron substrates. The table shows the constant (acid + anion) that can be dictated by the pH of the system.
/base cation equivalent ratio is illustrated. The relationship between constant (acid + anion)/base cation equivalence ratio and film formation under the influence of external potential is shown in Table 1.

Although the foregoing examples can be obtained by using acetic acid or formic acid, it is to be understood that these are merely illustrative of the acids that can be used and that other acids are also contemplated; The requirements are that such acid is complementary to the product and that the reaction RCOONH4+HAc-+RCOO
The strength and concentration of the acid is selected to perform H+NH4Ac (where Ac indicates the polymer species), but not only to do so but also not to cause cleavage of the resin.

Referring to Figure 3, the diagram shows the NH3 of the polymer to be coated.
This is a graph showing the tendency of the relationship between the equivalence ratio of /COOH and the thickness of electrodeposition, where A indicates the "dispersion" region and B indicates the "dispersion" region.
indicates the "metastable" region and C indicates the "solution" region. As seen in Figure 3, when the ammonia to carboxylic acid ratio changes from 1.0 to 0.00, the anode under the influence of external potential The thickness of the cured polymer coating formed with increases from about 0.1 mil to about 2.e! mil.

From about 0.0 to about 0.30 (6 dispersion area), NH3
The thickness of the electrodeposition changes only slightly as the ratio of /COOH changes. Approximately 0.30 to approximately 0.58NH3/CO
The OH(7)"metastable" region has the greatest impact on control methods. In the "metastable region," the OH(7)" is controlled by carefully titrating the acid in the polymer and controlling the ammonia to carboxylic acid ratio. , it is possible to accurately determine the increase in the thickness of the deposit on the anode once a current is passed through an aqueous solution of a "metastable" substance. NH3/COOH ratio is approximately 0.6
In the solution region, which occurs at around 1.0, the thickness of the deposit hardly changes even if the ratio changes, so this is generally a curve for adjusting the change in the thickness of the deposit. This is a less critical area of

The changes that occur in the NH3/COOH ratio, reflected in the PH in each case, change the thickness of the electrocoated resin without affecting the ultimate properties of the polyimide laminate after it has been fully cured. That is, the electrodeposited film formation can be varied;
and generally increases from thin to thick films, but such formation can occur gradually and in a controlled manner, and with little regard to the degree of molecular weight range, from relatively thin to relatively thick films. Increases into film.
Although there is no significant effect on the ultimate properties of the polyimide itself, it is possible to obtain various physical properties that are a function of the physical thickness of the polyimide and the molecular weight range of the polyimide. In general, any aqueous solution of resin can be used to advantage in carrying out the principles of the present invention. Resin systems and formulas are presented by way of example and not limitation and fall into the following categories: I Polyimide Polyester I Polyesterimide Single Head Polyacrylic - In general, what is required is that (1) the resin is produced by a synthesis appropriate thereto, (2) it is polymerized to the desired molecular weight range,
(3) Solubilization by the addition of ammonium hydroxide or other suitable base materials and (4) the pH of certain (acid decaion)/base cations of this type of resin, which can be directed by the pH. By changing the equivalence ratio, it is possible to adjust the desired distribution from the solution phase to the dispersed phase, thereby determining the thickness of the electrodeposited film.

In the case of polyimide polymers, a tetracarboxylic dianhydride is reacted with an aromatic diamine, and the reaction product is treated with ammonium hydroxide to convert the prepolyimide to an ammonium salt of polyorthoamic acid. A polyorthoamate repeat unit is produced having the formula:

The degree of imidization is determined by the desired molecular weight range requirements, in other words the viscosity tailored to the product.

Heating the electrodeposited material at a temperature of about 100 DEG C. to about 500 DEG C. produces a final polyimide having repeating units of the formula:

Other aromatic dianhydrides useful in the process of the invention have the general formula: where R represents at least one ring of 6 carbon atoms.
is an organic tetravalent group containing 100% carbon atoms and having benzenoid unsaturation, in which the 4 carboxyl groups of each unit are directly bonded to separate carbon atoms, and each pair of carboxyl groups is an bonded to a carbon atom).

These dianhydrides include, for example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride. , benzene-1,2,3,4-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenylmethane dianhydride, bis( 2,3-dicarboxyphenyl)methane dianhydride, 2,6-dichlornaphthalene-
1,4,5,8-tetracarboxylic dianhydride, 2,7-
Dichlornaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachlornaphthalene-1,4,5,8-tetracarboxylic dianhydride, naphthalene-1, 4,5,8-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 1 , 2,5,6-naphthalenetetracarboxylic dianhydride, 2,2',3,3'-diphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride anhydride, 3,4,9,10-phenylenetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 2,2-bis(
2,3-dicarboxyphenyl)propane dianhydride, 1
, 1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, and the like. Organic diamines useful in the process of the invention have the formula H2N-R'-NH2, where R' is (where Bi5 and R7 are alkyl or aryl groups having 1 to 6 carbon atoms. , n is an integer from 1 to 4, m has a value of 0, 1 or more) and δ《:》R
9 (where R2 is a carbon in an alkylene chain having 1 to 3 carbon atoms, and -O-, -S-, -SO2- and -N- (where R''' and Bi2 are the above-mentioned That's right, X
is an integer of at least 0);

Particular diamines suitable for use in the present invention include m-phenylenediamine, p-phenylenediamine, 4,4'
-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, benzidine, 4,,4'-diaminodiphenyl sulfide, 4,4L diaminodiphenyl sulfone, 3,3L diaminodiphenyl sulfone, bis(
-aminophenyl)diethylsilane, bis(4-aminophenyl)phosphine oxide, bis(4-aminophenyl)-N-methylamine, 1,5-diaminonaphthalene, 3,3'-dimethyl-4,4'-diaminodiphenyl -3,3'-dimethoxybenzidine, m-xylene diamine, p-xylene diamine, 1,3-bis-S-
aminobutyltetramethyldisiloxane, 1,3-bis-r-aminopropyltetraphenyldisiloxane and mixtures thereof.

Solvents useful in the solution phase of this invention are organic solvents whose functional groups do not react to any extent with any of the reactants (diamines or dianhydrides).

In addition to being inert to the system and preferably a solvent for the polyamic acid, the organic solvent must be a solvent for at least one of the reactants, and preferably for both reactants. An organic solvent is an organic liquid other than the reactants or homologs of the reactants, i.e., a solvent for at least one of the reactants, and contains functional groups, the functional groups being monofunctional primary and secondary It is a group other than an amino group and other than a monofunctional dicarboxylic acid anhydride group. Solvents of this type include dimethyl sulfoxide, N-methyl-2-pyrrolidone:N,N-dimethylmethoxyacetamide, N
- normally liquid organic solvents such as methylcaprolactam and tetramethylene urea, including pyridine, dimethyl sulfoxide, hexamethylphosphoramide, tetramethylene sulfone, formamide, N-methylformamide, butyrolactone and N-acetyl-2-pyrrolidone. Solvents can be used alone, in mixtures or in combination with solvents such as benzene, toluenine, cresylic acid, xylene, dioxane, cyclohexane or benzonitrile. Nitrogen-containing bases useful in the process of the invention include ammonium hydroxide (NH3), ammonium hydroxide (NH3),
NH4OH'). Charcoal. ammonium acid [(NH4)2C
03], and methylamine, ethylamine, Sec-
butylamine, isopropylamine, dimethylamine,
Includes primary and secondary aliphatic amines containing up to 4 carbon atoms such as diethylamine, dibutylamine, and the like.

j The acid for neutralizing the ammoniated compound may be any acid other than carbonic acid that does not have the effect of causing cleavage of the polymer and has a certain (acid + anion)/base cation equivalent, i.e. For this purpose, any relatively weak acid (except carbonic acid) can be used that has the effect of controlling the ratio of (COOH+COOe)/NHP, and the discovery that electrodepositing far exceeds that previously obtained This means that it is possible to obtain a film layer that is thicker than the previous one. Acid materials found to be useful include acetic acid, formic acid, butyric acid, propionic acid, benzoic acid, and the like. Addition of this type of acid is dictated by the PH according to the relationships shown in Table 1 and FIG. In order that those skilled in the art may better understand how to put the invention into practice, the following examples are included by way of illustration and not as a limitation of the invention.

All parts are parts by weight unless otherwise stated.

The electrodepositable water-soluble organic polymer obtained in each of the following examples can be electrodeposited by an electrodeposition apparatus 12 shown in FIG.

A copper wire anode 14 is immersed in an aqueous solution 16 that is stirred by a magnetic stirring bar 18 activated by a magnetic stirrer 20 .

Two spectrographic grade 7.5 ml carbon electrodes serve as cathodes 22 and 24 and are connected by conductors 28 and 30 to a DC constant power supply 32 with a voltmeter.

A milliamp meter 36 is connected in series from conductor 33 to anode 14 . The anode copper wire is degreased, pickled, and washed with water before coating. The aqueous solution is held in an inert container 34, such as glass. 1. Polyimide System Example 1 Referring to Figure 1A, 1309 N-methyl-2-
Pyrrolidone was added.

Then, while stirring, 3,3',4,4' of 16.19
-Benzophenonetetracarboxylic dianhydride was added. Next, add 10.19 P, p'- to the blender while stirring.
Methylene dianiline was added over 5 minutes. The maximum temperature during this period was 48°C. After running the compounder for approximately 10 minutes to produce a clear solution of polyorthoamic acid, the imidization rate was calculated from titration for carboxylic acid content and was found to be less than 2% imidized. At this point 10 ml of concentrated ammonium hydroxide was added over 1 minute with continuous stirring. followed by 100
ml of distilled water was added and stirred continuously for about 5 minutes. The resulting clear poly(ammonium orthoamic acid) solution was 10% solids based on polyorthoamic acid;
It had an absolute viscosity of 350 cp at °C. The ammonia content of the poly(ammonium orthoamate) solution is determined by titration and is such that the ratio of carboxylic acid to ammonium ions in the polymer is about 1.00/0.95. I understand. 10 obtained as above
% solids poly(ammonium orthoamate) 100
A mixture of 20 ml of 1.0N acetic acid and 23 ml of distilled water was added dropwise to the solution under vigorous stirring.

The resulting system of 7% solids based on polyorthoamic acid was a stable dispersion. PH-6.0 and calculated COOH/NH
3/NH4OAc=38/15/20 (COOH
is of the polymer, NH3 is bound, and NH4OAc is in solution), the dispersion is deposited to length 9 (V7) using the electrodeposition apparatus shown in Figure 2. !
40 mil copper wire can be anodized. Example 2 A further 1
009 poly(ammonium orthoaminate) 10m
A mixture of 1.0N acetic acid (1) and distilled water (33T111) was added dropwise with vigorous stirring.

The product system with a solids content of 7% based on polyorthoamic acid was a stable solution. PH=6.8 and calculated COOlVNHv
A solution of H4OAc-38/25/10 can be anodized onto 40 mil copper wire of length 9 (V7!) using the electrodeposition apparatus shown in FIG. % solids of another 1009 poly(ammonium orthoamate).
A mixture of 0N acetic acid and 1377# distilled water was added dropwise with vigorous stirring.

The resulting system of 7% solids based on polyorthoamic acid was a stable dispersion. PH=5.9 and calculated COOH/NH
Similar to Example 1 using a solution of 3/NH4OAc-38/5/30 to a length of 9? 40 mil copper wire can be anodized. Thermal conversion of the deposits to polyimide by this coating resulted in a film formation of 2.2 mils in diameter for the cured electrical film, whereas the immersion and draining method in the absence of an external potential produced a cured electrical film of 2.2 mils in diameter. A similar cured film thus formed was 0.15 mil. The coated copper wire was stretched by 25% and was found to pass the 2x winding test. The above example shows the effective CO using acetic acid.
It is shown that the thickness of the electrodeposit can be controlled for a given potential and time by the use of a back titration method to adjust the OH/NH3 ratio.

The following examples illustrate the use of other acids. Example 4 1009 poly(
A mixture of 20 ml of 1.0 N formic acid and 23 ml of distilled water was added dropwise to the ammonium orthoamate with vigorous stirring.

A 7% solids product based on polyorthoamic acid was produced as a stable dispersion. PH=6.0 and calculated COOH/NH
A 9 cm length of 40 mil copper wire may be anodized as in Example 1 using a dispersion in which 3/NH4FOA = 38/15/20. Comparative Example 1 According to Example 1 to a gas-liquid contact bottle 1
1009 poly(ammonium orthoamate) prepared to 0% solids was charged and brought to 7% solids with distilled water.

A CO2 cylinder was contacted with the gas inlet tube and CO2 was allowed to flow into the aqueous solution for several hours. Dispersions could not be made using this method. The solution remained clear. It can be seen from Examples 1 to 4 and Comparative Example 1 that the acid strength of acetic acid and formic acid is sufficient to produce a stable dispersion. Carbonic acid clearly has insufficient acid strength to form a dispersion. Example 5 Referring to FIG. 1, 5320f1 N-methyl-2- Pyrrolidone (NMP) was charged under nitrogen.

Then, 695.49 3,3',4,4L benzophenonetetracarboxylic acid dianhydride (BPDA) (2.16 moles, 99.5% purity) was charged and stirred for 2 minutes. Then, 218.29 P,p'-methylene dianiline (M
DA) (1.08 mol), 99.9% purity) was added with stirring over 5 minutes and allowed to stir for an additional 15 minutes,
The temperature was then controlled at 25° C. to form a BMB precursor. An additional 218.49 MDA (1.10 mol) was then added continuously with stirring over a period of 15 minutes,
The temperature was controlled at a maximum of 40°C. The polyimide prepolymer which is the polyorthoamic acid produced is 17.5%
It was solid and had an intrinsic viscosity of 0.67 d1/9 as measured at 37.8° C. at a concentration in NMP of 0.500 d1/9. The imidization rate was determined to be 1.5% by titration of the carboxylic acid content in pyridine with tetrabutylammonium hydroxide and thymol blue as indicator. Molecular weight adjustment was carried out under nitrogen and at 40
9. as a solution in NMP of 5009 at a maximum temperature of 0.degree.
This was done by a back titration method (see US Pat. No. 3,663,510) consisting of continuous addition of 6 g of BPDA with stirring for 5 minutes, followed by a further 60 minutes of stirring. The polyorthoamic acid produced was 16.3%
solid content, imidization rate of 1.501) and 0.90d1
It had an intrinsic viscosity of /9. Then, 600f! was applied to the reactor.
P,p' of 0.4009 previously dissolved in NMP of
- Methylene dianiline was added with stirring under nitrogen. The addition was carried out continuously with stirring over a period of 5 minutes and the temperature was controlled at 35±3°C. Stirring was continued at this temperature for 30 minutes. The intrinsic viscosity of this polymer is NM
The concentration in P was measured at 37.8° C. at 0.500 d1/9 and was 0.87 d1/9. It was found that the produced polyorthoamic acid had a solid content of 15.0%, an absolute viscosity of 3700 cp at 25°C, and an essentially unchanged imidization rate of 1.5%. The polymer solution 2009 obtained above was charged into a General Electric type compounder, and 9.09 (10.0 mol) of concentrated ammonium hydroxide solution (28% by weight NH3) was added thereto. It was added gradually and with stirring.

This was followed by the addition of 1009 water slowly and with stirring. The resulting clear solution had a solids content of 10.0% based on polyorthoamic acid and a pH of 9.2.
The viscosity of this liquid was 525 cp at 25°C. Ammonia content was determined by placing the sample in a 50% by weight aqueous sodium hydroxide solution and heating to evaporate the water and ammonia. Ammonia was absorbed in 0.1N HCI and excess acid was titrated with 0.1N Na0W to a promthyol end point. The amount of ammonia is NHν℃00H
= 1.00/1.18, COOH/NH3 ratio = 1.00
/0.85. As mentioned above, 1
100f manufactured to 0.0% solid content! A mixture of 19 ml of 1.0 N acetic acid solution and 19 ml of distilled water was slowly added to the poly(ammonium orthoamic acid) with stirring to obtain a solid content of 7.2% based on polyorthoamic acid. PH=6.0 and calculated COOH/NH3/NH
A stable dispersion of 4OAc=38/13/19 was obtained. This dispersion was prepared using the apparatus shown in FIG.
! can be effectively used to anodize 40 mil copper wire.
Example 6 10 prepared according to Example 5 with 10.0% solids, PH-9.8 and NH,/COOH=1.00/1.18
A mixture of 9 ml of 1.0 N acetic acid and 29 TfL of distilled water was slowly added to the poly(ammonium orthoamic acid) of No. 09 while stirring to give a solid content of 7.201), pH based on polyorthoamic acid. =6.7 and calculation C
A stable solution of OOH/NH3/NH4OAc=38/23/9 was obtained.

This dispersion was prepared in the same manner as in Example 1 to a length of 9 mm. used to anodize 40 mil copper wire. Example 7 10.0% solids, PH=9.2 and NH as per Example 5
1009 manufactured at 3/COOH=1.00/1.18
of poly(ammonium orthoamate) to 31 ml of 1
．． A mixture of 0N acetic acid and 7Tn1 of distilled water was added slowly and with stirring to give 7Tn1 based on orthoamic acid.
．． 2% solids, PH=5.8 and calculated COOH/NH3
A stable dispersion of /NH4OAc=38/1/31 was obtained.

This dispersion was prepared in the same way as in Example 1, with a length of 9Cr 1L.
Used to anodize milled copper wire. Example 8 According to Example 5, 10.0% solids, PH=9.2 and NH,
38TI11 of 1.0N acetic acid was slowly added to 1009 poly(ammonium orthoamate) prepared at COOH=1.00/1.18 with stirring.

7.2% solids based on polyorthoamic acid, PH=5.
6 and calculation COOH/NH3/NH4OAc/HOAc
An unstable dispersion of =38/0/32/6 resulted. This dispersion slowly aggregated and settled as spheres at the bottom of the beaker, leaving a cloudy supernatant with a pH of 5.6. Example 9 10.0% solids, PH=9.2 and NH as per Example 5
1.0 ml of nonylphenol ethylene oxide adduct wetting agent was added dropwise by syringe to the vigorously stirred 1009 poly(orthoamino acid ammonium) prepared at 3/COOH/=1.00/1.18.

Next, 1. of 38Tn1 was added slowly and while stirring.
0N acetic acid was added. 7.2 based on polyorthoamic acid
% solids, PH=5.6 and calculated COOH/NH3/N
A stable dispersion of H4OAc/T-10Ac = 38/0/32/6 resulted. This dispersion is used to anodize 9 cm (7) lengths of 40 mil copper wire in the same manner as in Example 1. 2. Polyester Example 10 Ethylene glycol/terephthalic acid/glycerin = 2/
The polyester of 4001, formed in a 3/1 molar ratio and then reacted with 1.5 phr of pyromellitic dianhydride, was dissolved in tetrahydrofurfuryl alcohol of 6009 at 125°C to yield a clear solution.

This solution was then dispersed with vigorous stirring into 5-20 DEG C. water containing 2% nonylphenol ethylene oxide adduct wetting agent, resulting in a total resin solids content of 23%. The pH of this system is adjusted by adding ammonia water to NH3/
Adjustments were made by changing the COOH ratio. PH of 11
The polymer was a clear solution.

The above polyester prepared to 22% solids at PH=11 was treated with 1.0N acetic acid dropwise and with vigorous stirring to reduce the NH3/COOH ratio and to reduce the NH3/COOH ratio to PH=9.
It was set to 1.

A stable dispersion with pH=9.1 was obtained. This is length 2
Used to anodize 32 mil copper wire. Example 11 The polyester of Example 10 was treated with acetic acid by a procedure similar to that described in Example 10 to greatly reduce the overall NH3/COOH ratio to a pH of 8.3.

This solution is used to anodize 20 CTIL lengths of 32 mil copper wire. Example 12 The polyester of Example 10 is treated with acetic acid by a procedure similar to that described in Example 10 to give a pH of 7.8.NH3/COOH
It was compared.

This solution is used for anodic deposition on copper. Example 1
3 Ethylene glycol/dimethyl terephthalate/glycerin - 4009 polyester formed in a molar ratio of 2/3/1 and then reacted with 0.7f1 pyromellitic dianhydride was added to 6001 tetrahydrofurfuryl alcohol at 125°C. Dissolve, cool to 23°C, reheat to 90°C, cool to 23°C, then disperse in water containing 2% non-ionic wetting agent with vigorous stirring at 5-10°C to obtain a total solid. 17%.

The pH of this system is changed by introducing ammonia and NH3/CO
It was increased by increasing the OH ratio and aqueous ammonia was added to give pH=9.1. The polyester obtained as described above was diluted with 1.0N acetic acid to pH=
NH3/COO exhibiting 7.3 and producing a stable dispersion.
Adjusted to H.

3. Polyesterimide system example 14 Ethylene glycol/trishydroxyethyl isocyanurate/terephthalic acid/reaction product of 2 moles of trimellitic anhydride and 1 mole of methylene dianiline = 2/1
4001 polyesterimide formed in a molar ratio of /1/2 was added to tetrahydrofurfuryl alcohol at 130°C.
Upon dissolution at , a clear solution was produced which remained in solution at 23°C.

This solution was combined with 2% nonylphenol ethylene oxide adduct wetting agent and the resulting NH3/COOH ratio
= 5 to 1 containing ammonia to the extent that it shows a system of 9.1
It was dispersed in water at 0° C. with vigorous stirring. The polyesterimide thus obtained was treated with 1.0N acetic acid to reduce the NH3/COOH ratio of the polymer.
H decreased from 9.1 to 7.3.

4. Head-to-Head Polyacrylic System Example 15 Equipped with a stirrer, controlled atmosphere, and diluted with 480 ml of distilled water, 37.0 WLI of concentrated ammonia water (28
．． 0 wt% ammonia) in a reaction vessel containing 2500
The methyl semi-ester of ethylene-maleic anhydride copolymer of 79.09 in the molecular weight range of 0 was added slowly and with stirring.

NH3/COOH equivalent ratio of 0.95/1.00 and 8.
A clear solution of 15.8% solids by weight with a pH of 5 was produced.

The N of the polymer in 50.0 ml of this 15.8% solids system
Hν℃00H ratio is 50. (g) Adjustment by addition of 0.5N acetic acid in d with stirring produced a stable solution giving a polymer NH3/('00H ratio of approximately 0.5/1.0 and a pH of 6.2. .

Example 16 15.8% solids system prepared according to Example 15 50. (g) Adjusting the NH37900H level of the polymer in d by adding 50 ml of 1.0N acetic acid with stirring results in a polymer NH3/COOH ratio of approximately O/1 and a Z'P of 5.0.
A stable dispersion was formed that gave H.

Prolonging the time at constant voltage in the electrodeposition of the solutions and dispersions of Examples 15-16 resulted in correspondingly larger formations in each case, and the final current remained approximately constant over double and triple times. .

For example, the film formation obtained in 10 seconds was 1.6 mils for the dispersion of Example 16 and 0 mils for the solution of Example 15.
．． 8 mils, and for the solution of Example 15 was found to be 0.6 mils. Similarly, changes in voltage play a large role in the resulting film structure and desired electrocoated film performance characteristics. The proportions of voltage, current, time and polymer solids level of the solution or dispersion must be determined keeping in mind the metal substrate provided with the final product.
Such proportions are readily determined experimentally by those skilled in the art. It is well known to those skilled in the art that the teachings of the present invention apply to films for a given polymer by controlling the NH,/COOH ratio using the volatile base and acid additives shown in the examples above. Controlling the formation of films from polymers in solution in a single process and without changing the properties that a particular polymer can exhibit. In both of the foregoing examples, electrodeposition was primarily derived from a dispersed phase of resinous material.

Incidentally, some solution phase resin material is also electrodeposited, but this is only incidental. The basic discovery of the present invention is the use of a dispersion of particles as a coating source, and it is in this phase that the inventors expect to obtain improved results. Therefore, the inventor carefully adjusts the value of PH to ensure that dispersion occurs and to the extent that the electrocoat is derived primarily from such a dispersion source. Also, in order to achieve electrodeposition from a dispersed phase, as distinguished from electrodeposition coatings derived primarily from solution phase resins, the necessarily varying voltage is also adjusted, as is well known to those skilled in the art. This latter factor is not easily quantified as it does not vary with resin system and PH. Nevertheless, it is a factor and a sufficient factor to consider in the present invention. To eliminate the above-mentioned difficulties, electrodeposition is difficult because high voltages tend to result in electrodeposition from the solution phase as opposed to dispersed phase resins, thus impairing the good results that characterize the present invention. Transient voltages are clearly avoided.

Forming a resin system with reactive pendant carboxyl groups on relatively small molecular chain units and repeating such carboxyl groups along the length of the molecule, the carboxyl groups are removed with a nitrogen-containing base. The polymer can be made water-soluble by reacting with.

Water is then added to the system so that a combined organic/aqueous solvent system is present. Then, in order to make the polymer preferentially insoluble, the ratio of [COOH+COOe''3/NH4l] was adjusted by acid titration with relatively weak acids (but excluding carbonic acid), and the insoluble dispersions and solutions of the gourd polymer were prepared. Two phases result.It has now been discovered that the amount of dispersion can be adjusted by the simple means of addition of acid and that the amount of dispersion controls the electrodepositivity of the resin, allowing for larger thicknesses. As used herein, the term ``dispersion'' is used in its conventional sense to include suspensions of particles in a liquid continuous phase of organic and aqueous solvents. be done.
The improved coating is obtained primarily from the dispersed phase polymer. Note that the embodiments of the present invention are as follows. (1
) from about 3.0 to vary the thickness of the electrodeposition on the metal substrate.
5. The method of claim 1, comprising adjusting the ratio of carboxylic acid to ammonia to a pH of about 6.5. (2) The method according to the claims, wherein the precursor is a reaction product of an aromatic dianhydride and an aromatic diamine.

(3) The method of paragraph 2, comprising heating the raw product of paragraph 2 to at least partially imidize the prepolymer polyamideimide to a preferred viscosity.

(4) One molecule of the prepolymer consists of XYX or YXY (where X consists of an aromatic dianhydride and Y consists of an aromatic diamine), and the reactant is a molar excess of Y or 2/1 molar ratio in an organic solvent by adding and then back titrating with Y to the desired molecular weight of the reaction product.

(5) The Or the method according to item 4, which comprises heating the YXY system. (6) The method according to item 4, wherein the ratio of aromatic dianhydride and aromatic diamine is close to 1/1 so that back titration produces a reaction product with a preferred molecular weight.

(7) The method according to item 4, which includes terminal-capping the reaction product with an aromatic diamine.

(8) The method according to item 7, wherein the acid is selected from the group consisting of acetic acid and formic acid. (9) The method according to item 7, wherein the solubility of the resin is gradually decreased by adding resin to increase the proportion of insoluble resin, thereby increasing the amount of deposit on the substrate.

The 00a polymerizable organic product is reacted in an organic solvent in which the functional groups do not react with any of the reactants to form the following formula along the polymer chain, where R and R' are (1) A compound of a carboxylic acid anhydride and a diamine, (2) a compound of a condensable polycarboxylic acid and a polyhydric alcohol, (3) a first ethylene group having a first pendant group and a second pendant group. (4) having a carboxylic acid repeating unit selected from the group consisting of cross-linking polycarboxylic acids, polyhydric alcohols, polycarboxylic acid anhydrides, and diamines; forming a polymer, b
Partially neutralizing the carboxylic acid units with a nitrogen-containing base to control the ratio of bound carboxyl to base to make the polymer water-soluble, and c adding water to a solution of the partially neutralized polymer. and d back-titrating the aqueous solution to form a combination of dispersion and solution phases that are electrodepositable according to the proportion of the resin made water-insoluble as a dispersion. A method for producing a water-soluble organic polymer.

A method according to paragraph 10, comprising: a1) combining the aqueous solution of the resin and the oxide adduct wetting agent and matching the amount of organic solvent/water to form a dispersion when the back titration is performed.

02) The resin system consists of repeating units of the following general formula, and a base is added to provide a constant (acid + anion)/base cation and to make the resin system water soluble, and acetic acid , formic acid, and ammonium hydroxide.
The first method of controlling the electrodepositivity of the resin system by adjusting the ratio of base cations to form two phases, a dispersed phase and a solution phase.
The method described in item 0.

03) a) A polymerizable organic material is reacted in an organic solvent system to form a compound of the following general formula along the length of the polymer, where X and Y are selected from the group consisting of polyimide, polyester, polyacrylic and polyesterimide. b) at least partially neutralizing the carboxylic acid units with a nitrogen-containing base to render the polymer water-soluble; c adding water to the solution; d adjusting the effective ratio of COOH/NH3 by back titration with a weak acid, thereby controlling the proportion of dispersed phase polymer to solution phase polymer;
This consists in adjusting the electrodepositivity.

A method for producing a water-soluble resin solution for electrodeposition. (auto) base is ammonia, ammonium hydroxide, ammonium carbonate, and 4
14. The method of claim 13, wherein the amine is selected from the group consisting of primary and secondary amines containing up to 1 carbon atoms.

14. The method according to item 13, wherein the acid for back titration is selected from the group consisting of acetic acid, formic acid, butyric acid, propionic acid and benzoic acid.

A6) The method according to paragraph 13 above, wherein water is added to the organic solvent system in an amount that adjusts the organic solvent/water ratio so as to provide a dispersion capable of electrodepositing the resin from both the dispersed phase and the solution phase. .

(5) Polyimide [wherein R is an organic tetravalent group containing 6 carbon atoms and at least one ring with benzenoid unsaturation, and the 4 carboxyl groups of each unit are directly connected to another carbon atom] each pair of carboxyl groups is bonded to an adjacent carbon atom in the ring of the R group, and R' is [where R''5 and R'M
is an alkyl or aryl group having 1 to 6 carbon atoms, n is an integer from 1 to 4, m has a value of 0, 1 or more] and {wherein R} is 1 to 3 carbon atoms in the alkylene chain, as well as -O-, -S-, -SO2-, and -N- (R'' in the formula
' and 'are as described above, and X is an integer of at least O), and are selected from the group consisting of oxygen, silicon, phosphorus, and sulfur]
14. The method according to item 13, wherein the method is derived as a reaction product of

[Brief explanation of the drawing]

FIG. 1 illustrates forming a precursor, then activating the precursor to form a polyorthoamic acid, adjusting the desired molecular weight range, end-capping the polyorthoamic acid, and activating the precursor to form a water-reducing polyorthoamic acid. (ammonium orthoamate) and then P before electrodeposition to obtain the desired film thickness of the electrodeposited resin.
1 is a flow sheet illustrating a method consisting of adjusting H; FIG. 1A is an o-sheet illustrating the method of forming the precursor using the 1 method. FIG. 2 shows the equipment used for electrodeposition. Figure 3 shows the film thickness versus NH3/
It is a graph illustrating the relationship of COOll'5. The symbols representing the main parts in the figure are explained as follows. 12... Device, 14... Copper wire anode,
16...Aqueous solution, 18...Magnetic stirring bar, 20...Magnetic stirrer, 22...Cathode, 24...Cathode, 28・・・・・・Conductor, 30
・・・・・・Conducting wire. 32...DC constant power supply source with voltmeter, 33...Conductor wire, 34...
・Container, 36...milliamp meter.

Claims (1)

[Claims] 1. A method for producing an electrodepositable water-soluble polyorthoamic acid, comprising forming an aqueous solution of a salt consisting of a polyorthoamic acid and a nitrogen-containing base, the method comprising: adding a weak acid (excluding carbonic acid) to the aqueous solution; precipitating a portion of said salt, thereby producing a composition containing a solution phase and a dispersed phase, the proportions of said two phases being determined by the proportion of weak acid added to said aqueous solution. A method for producing a water-soluble polyorthoamic acid that can be electrodeposited.