DE1765738A1 - Electric conductors - Google Patents

Description

DR. I. M. MAAS

DR. W. ΟΙ PFEIFFER PATENTANWÄLTE MÖNCHEN 23 UNGERERSTR. 25 - TH .. »O2J6

252 557 / C

Standard Oil Company, Chicago 111., V. St. Λ. Electric conductors

The invention relates to electrical conductors with a dielectric coating and is characterized in that the Coating an insoluble in polar organic solvents, infusible o Polyamidiinidharz iat »this mainly from repeating units of the formula

NO..

where R is a divalent aromatic group, consists *.

Since β uneehmelebare polyamide i midharz from which the coating according to the

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Invention exists, and its manufacture Bind in patent (patent application by the same applicant dated

the same day with the internal file number 252 557 / B) and are briefly explained below.

The new polymeric products are made from an acyl halide derivative of trimelitic anhydride (benzene-1,2,4-tricarboxylic anhydride) with at least one acyl halide group in the 4-position of the benzene ring. This includes that 4-carboxylic acid chloride, the 1,4- and 2,4-dicarboxylic acid chloride (with an ester group in the remaining position) and the 1,2,4-tricarboxylic acid chloride. The bromides and other reactive halides are also suitable.

The acid halide is associated with an aromatic diaraine one or more aromatic rings and two primary amino groups reacted. The aromatic part of the diamine provides the thermal properties for the polymers, while the primary Amino groups promote the formation of the desired imide rings in the poly enable meren. The aromatic diamine generally contains 1 to 4 aromatic rings, preferably 1 or 2 aromatic rings Rings and especially 2 aromatic rings. The aromatic diamines with more than one aromatic ring can also be used as characterized polyoyolic aromatic compounds with two primary amino groups on a polyoyolic aromatic nucleus will. The aromatic rings can be fused, as in structures of the type of naphthalenes or phenanthrenes, or

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directly as in dephanyl amines or indirectly, for example Threatened reection-overcoming bonds "e.g. an" oxy-, carbyl- (■ carbon linked with 2 or fewer hydrogen atoms), Carbonyl, sulfonyl, or some other relatively inactive Group, like a sulfide group, to be connected »As examples of the carbyl group may be methylene * xthylene and substituted derivatives such as 1,1-diaethylmethylene. Suitable aroma tic cores include benzene, naphthalene, anthracene, Haphthacene, diphenyl, terphenyl, phenylnaphthalene, quaterphenyl and by oxy, carbyl, carbonyl, sulfonyl and thio ■

aromatic hinge separated by groups. Bs is advantageous if the bonds between the aromatic groups are oxy or methylene groups and the amino groups are in the m <- or p-position on the aromatic ring. Preferred diamines for the production of wire aail or dielectric coatings are p, p ^f -ethylene-bi8- (aniline) and p, p'-oxybis (aniline).

Usually the reaction in the presence of an organic polar solvent such as Ν, Η-dimethylacetamide, H-methyl-. _ pyrrolidone, I,! - Dimethylformamide and Diaethylsulfoxyd ·, whereby H, Η-dimethy! acetamide and N-methylpyrrolidone and especially, Η, Μ-dimethylacetamide are preferred. The reaction should be carried out under practically anhydrous conditions and at a temperature of below are preferably carried out at about 50 ⁰ C for about 70 ⁰ C, but aufih temperatures up to approx .. 25 ⁰ C are very suitable. The reaction time depends on the temperature and varies from about 1-24 hours.

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BAD OBIGINAt

th at 50 to 70 ⁰ C with reaction times of 2 to 4 hours iet eu recommend.

The reactants are preferably in practical equimolar ratio. Fluctuations within a range of + 3 mol ~ # of one or the other output meter usually have only negligible effects on the properties of the products.

The reaction between acid halide dea of trimellitic acid anhydride and the Diomin leads to a high molecular weight polyamide with an amide content of over about $ 50> of the bonds between the units dee polymers. Such products are easily soluble in organic solvents such as dimethylacetamide, N-methyl-pyrrolidane, Ν, Ν-diraethylforamide and Ν, Ν-dimethyl sulfoxide.

The reaction thus leads to the formation of solid polymers with a high Molecular weight and forming properties that are soluble in organic polar solvents. With «Solve in a solvent such as N, N ~ dimethylaoetamide, the polymers have a lower limit of viscosity of about 0.2 (defined by W.R.Sorenson and T.V. Campbell in Preparative Methods of Polymer Chemistry 1961, p. 34) based on a polyamide made from ρ, ρ'-methylenebis (aniline) as a standard. The lower limit of the inherent viscosity varies somewhat with the particular diamine used. For example, the lower inherent Viβ-

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The viscosity of the polyamide made from ρ, ρ'-oxybie (aniline) is about 0.3. Particularly suitable polyamides aua ρ, ρ'-K · thyIenbiβ (aniline) and p, p'-oxybi8 (aniline) have inherent viscosities In of the order of 0.3 and 0.5 respectively. These viscosities indicate that the polyamides have molecular weights of about 2500-5000 and own above.

The polyamide formed in the first reaction is usually soluble in substantial amounts in highly polar organic solvents. Based on N, N-dimethylaoetamide, solutions with a solids content of about 15 to 50 wt .- # ™ are obtained. that the solutions contain about 25 to 40 wt .- ^, preferably 35 wt .- 56 solids. With concentrations of this kind one obtains solutions which, for most practical purposes, have a good compromise between moisture content and viscosity values useful for processing. The viscosities of such solutions are in the range of 10-400 poise. The viscosities of φ

^, If-Dimethylacetamidlöeungen with a solids content of about For example, 30 Ji is about 50 poise.

Ia following is an example of making the new Given to polymers.

Trimellitic anhydride bee 4-acid chloride, which practically

does not contain any free trieellitic anhydride, is

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Fourth form used. The acid chloride and p, p * -Methylenbie (aniline) or ρ, ρ'-Oxybis (aniline) are mixed together in equivalent amounts (t 0.1 mol- #) and the mixture then becomes N, N ~ dimethylacetamide with a Water content of less than about 0.3 wt. -F> given. The N, N ~ Dimethylaoetamid was previously cooled to 5 to 10 ⁰ C and purged with dry nitrogen at the same time ^ During the addition, the mixture dee the Reaktlonsfceilnehmer a cooling bath used to maintain the temperature of the solution at about 50 ⁰ C. The addition is completed after about 15 to 30 minutes, after which heat is added with the aid of a warm water bath, because the reaction is then usually not sufficient to maintain a temperature of 0 ° C. After a few hours (about 2 hours), the viscosity generally peaks. The polymerization is practically complete and the reaction mixture is cooled to room temperature and can be stored overnight without any risk of degradation for the product. However, it is preferred to store the food at a temperature of about 5 ° C. At this temperature, ea can be left for long periods of time without any noticeable change in yiakoaity.

At this stage, the polyamide solution (reaction mixture) already suitable. However, the polyamide solution is preferably a treatment to remove from the acid

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halide ataeaenden subjected to hydrogen halide. The treatment can usually either be by precipitation of the polyamides be carried out in water, washing the precipitate and, if necessary, renewed formation of the polyamide solution, or one know the polyamide solution with an aluminum oxide, such as ethylene oxide or i'ropylenoxyd treat, which is with the Holügen hydrogen converts to form a compound which can be volatilized during the sswide reaction. At the first treatment the polyamide, which contains the hydrogen halide, becomes Advantageously to a viscosity of about 150 poise set and can be poured into a large excess of water with moderate stirring. The polyamide solution will then poured from a height on the order of about 60 cm (2 feet) above the water level to avoid the failure of a to effect endless thread on the Rühratab. When the container is filled with a loose ball, the liquid is removed and the polymer is fresh for about an hour Water put in, wo'es more solvent and more Loses hydrogen chloride. The measure of the drip and Soaking the polymer in fresh water is usually repeated 2 or 5 times or more times. After all, the Polymer thread soaked over power and once more with water washed. Another soaking, draining and drying at about 49 ° C can be carried out if the polymer is to be stored for long periods of time. In this state leaves A solution of the polyamide with a solvent can easily be prepared because it has a large surface area.

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Instead of threads, the precipitate can also be shaped produce small particles by pouring the polyamide solution into water, which is passed through a comminution device, e.B « a Cowles ^ lion is moved vigorously. Through this device the precipitate is hacked into small particles, which become usually easier to weigh and transport than the felled thread.

The polyamide can also be subjected to the treatment to remove the enclosed hydrogen halides directly in solution. For example, a scavenger, for example alkylene oxide, can be added to the solution, whereby the hydrogen halide can be converted into a form which no longer attacks the polyamide and can be removed in vapor form during the second reaction. By way of example for this treatment is the addition of ethylene "or propylene oxide to a polyamide solution in quantities you about 1-8 mol / Hol halide (calculated from the Acylhalogeniö) whereby upon Bohandlungszviten 1 hour ODTR including at IiO ⁰ C or preferably from .2 to Satisfactory results can be obtained after 3 days at room temperature.

As already mentioned, the soluble polyamides are transformed by an internal imidization reaction through heat introduction - in a viscous » converted to infusible and insoluble polyamide-imide resins. For example, a solution is the reaction product, the one Subjected to treatment to remove hydrogen halides

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had been bie a wire aufgebracht.und to a temperature of about 200 Ton 42O ⁰ C, heated preferably about 300 to 40O ⁰ C until the insoluble forms Polyamiditnld. At 400 ^° C., around 1 minute is sufficient, while at 300 ^° C., around 2 minutes are required.

The conversion of the soluble polyamide into the meltable form lies within the scope of the invention and is carried out by curing the soluble polymer at an elevated temperature the curing temperature used and the curing time depend on ™ from one another and are chosen so that the carboxyl and amide groups are essentially converted into imide groups and as a result, the polymer which is insoluble in organic polar solvents is formed.

In another embodiment of the invention, the partially polymerized or uncured polyamides can be denimldized, thereby producing products of increased solubility and their use in the form of solutions with a high φ Feetetoffhalt and relatively low viscosity, is possible. For example, the soluble polyamide will be To increase solubility in relation to the viscosity of its solutions, first treatment with a dilute aqueous alkali solution, e.g. of sodium hydroxide or potassium hydroxide or the corresponding carbonates and bicarbonates (usually

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0.1-0.5 a NaOH or KOH). The product obtained by such treatment is then treated with an aqueous dilute solution of an acid such as sulfuric acid, hydrochloric acid, nitric acid or other mineral acids, usually 0.1 to 0.5 η HCl, with the formation of a polymeric product treated, which has increased solubility in an organic polar solvent.

When treated with the alkali solution, the polymer door is usually in solution and forms a polyamide precipitate, which is then treated with the acid solution. The acid-treated precipitate is then redissolved in the same solvent or other suitable organic polar solvent to give a solution having a higher ratio of polyamide solids to viscosity. The treatment described above converts, for example, a polyamide which, in N _t N-dimethylacetamide, forms a solution with a polyamide solids content of 20 % at a viscosity of 100 poise into a polyamide which, in the same solvent, has a solution with a polyamide solids content of 35 1> results in the same viscosity. On the other hand, where lower viscosities are desired, a polyamide solution in Ν, Ν-dimethylacetamide or N, HD ime thy If ο rna mid ait 15 > Feetoffhalt at 30 poise, for example by the above

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the treatment described in a solution with the same Feetotoff, but a viscosity of about 0.6 poise.

The treatment described above leads to polyamides which in the named solvents, preferably H _? Ti-methylacetamide and N _# K-dimethylformemide solutions with features of 15 ~ 70 fS and viscosities in the range from about 1 to 50 poise result.

The following examples illustrate the invention without representing it restrict.

example 1

A mixture of 1.05 g (0.005 mol) of trimellitic anhydride with a 4-position acid chloride group (prepared from TrimelXitheic anhydride and sulfonyl chloride), 1.0 g (0.005 mol) of ρ, ρ'-oxybls (aniline), 6 g of N, N- dimethylacetamide (solvent) and 6 g of toluene (as a solvent) is flushed in a 3 Hül8glaskolben with nitrogen Ea erfo% t an exothermic reaction, due to which in a few minutes a maximum temperature is reached of 40 ⁰ C. After stirring for 30 minutes, the temperature falls back to room temperature. The passage of nitrogen is slowly continued. After an initial-

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The viscosity drops in about 2 hours again to a constant value. The solution is left to stand for 16 hours at room temperature with the exclusion of air, and the reaction is then carried out. A polyamide is formed.

The polyamide solution is applied to a wire and heated to ^{300-40O 0 C for about 2 minutes.} For testing purposes, the polyamide is processed into a film and heat-cured.

Example 2

2200 ml of dry Ν, Ν-dimethylacetamide are poured with nitrogen while stirring in a glass flask at room temperature. Then the 4-acid chloride of trimellitic anhydride and the p, p '~ oxybis (aniline) are introduced into the flask alternately in portions of 20 g each. A total of 421 "24 g of the acid chloride and 400.48 g of the amine with such Geschwindigkeitüjsugegeben that the temperature of the reaction mixture at 20 - 40 ⁰ C remains. Then the passage of τοη nitrogen is continued with stirring for a further 16 hours.

The viscous solution obtained is poured into a poured a large excess of water, creating a low ■ blow forms. The precipitated polymer is then washed several times with water to remove any remaining HCl and solvent Remove EU .. Then it is mixed with acetone and again with water.

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wash and dry in a vacuum oven at about 35 ^{° C.} The procedure described in Example 1 is used to coat wire.

500 g of the hydrochloric acid-free polymer are then dissolved in 1000 ml of Ν, Ν-dimethylacetamide. This solution is further diluted with 690 g of toluene in order to bring the solids content to the same value as an available solution of a polymer obtained from pyromellitic acid dihydride and ρ, ρ ^f «oxybis (aniline) in N ₉ N-dimethy! acetamide and toluene.

Awaken to test "is propagated of polyamides in N, N-dimethylacetamide and toluene on a copper plate of 0.6 mm (24 gauge) into a film thickness and baked 10 minutes at about 204- ⁰ C (400 ⁰ P) part. The dry film is 12.7 microns (1/2 mil) thick and is yellow and clear.

Example 3

The polyamide film obtained according to Example 2 was compared with a polyimide film used industrially as a wire enamel, which was produced from pyromellitic dianhydride and ρ, ρ'-oxybis (aniline). The polyimide film was produced at the same baking temperature (204 ^° C.) and in the same baking time (to minutes) as the polyamide film.

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The long-term impact strength of both films was over 181 cm.kg (160 in.lbs) which is a very positive value. The heat resistance was determined by exposing each film to the flame of a Bunsen burner, both films exhibiting very good heat resistance. The films were also subjected to an alkali test, a drop of 2 # NaOH being applied to each film and left on for overnight. The standard values of this technical test are: useful, whereby the film is practically not attacked by the alkali, and unusable, wherein the film is partially dissolved, made brittle or lifted off by the alkali. Here, the polyamide film was found to be useful, while the polyimide film was rated as unusable. After a baking time τοη 20 minutes (10 minutes longer) at 204 ⁰ C the PoIyimidfilm in the examination proved stwar be useful, but the / lkalitropfen had a dark stains left thereon. The polyamide film, which was also baked for 20 minutes, was alkali-resistant without being darkened by the alkali

Examples 4-6

For comparison purposes, products by converting trimellitic anhydride and! p, p'-oxybi8 (aniline) and made from trimellitic anhydride uad p, p'-methylenebie (aniline). A mixture of sub 1 _e 9212 g (0.01 mol) of trimellitic anhydride and 2 ₀ 0024 g (0 _p 0i mol) ρ, ρ ¹ · oxybie (aniline) were used to

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heated to form a melt and then held at about 250 ° C for about 1/2 hour. The molten state remained only temporarily, after which the mass quickly solidified again. She was then in about 764 ral N, N - / dl gelbat Dimethyleoetamid to a solution with a Konientration O ₅ .5 g. The inherent viscosity of the product was found to be 0.08. It was also found that the product in Ν, Ν-dimethylacetamide yielded no Lösengen with concentrations of about 5 $> solids.

A second mixture of 1.9212 g (0.01 mol) of trimellitic anhydride and 1.9827 g (0.01 mol) of p, p -methylene bis (aniline) was added to 10 ml of Ν, Μ-dimethyl acetaxide. The mixture was heated ^{to about MO 0} C for about 1/2 hour. The solution was diluted to 0.5 g / dl with about 774 ml of NN-dimethylaeetamide. The inherent viscosity of the product was about 0.07. A robe of the solution before dilution was also painted on a metal surface and subjected to baking temperatures. Only a black, brittle and heterogeneous film was formed, from which it can be seen that the material is unsuitable for the production of coatings.

A third mixture of trimellitic anhydride (0.1 mol) and ρ, ρ'-oxybie (aniline) (0.1 mol) was reacted in 59.5 g of N, N-dimethylacetemide. The temperature of the solution was initially about 25 ° C _; rose due to a massive

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exothermic reaction to about 40 ⁰ C and reached after addition of 10 g of N, N ~ dimethylacetamide about 50 ⁰ C and was about 3 1/2 hours, maintained at that value. After falling to room temperature, a further small amount of Ν, Ν-dimethylacetamide was added. A portion of the solution was diluted to 0.5 g / dL and showed an inherent viscosity of about 0.11. A second portion of this solution was spread and .for about 316 ⁰ C for 2 to 4 minutes eingebranntr In this opaque black and brittle films ^ formed which were brittle on bending and cm.kg possessed a bending fatigue strength of only about 2.3. The adhesion was also very poor and the coating could easily be peeled off the surface.

The above results indicate that the products from trimellitic anhydride have much lower inherent viscosities and much inferior properties than that Products from the 4-acid chloride of trimellitic anhydride. The inherent viscosities of the first-mentioned products were 0.08, 0.07 and »0.11 and are therefore very much lower than that inherent viscosities of 0.2 to 0.6 of the polyamides obtainable according to the invention, which indicates that the free Trimellitic anhydride products are much less Molecular weight as the products cue the 4-acid chloride of trimellitic anhydride.

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BATH ORIGINAL

Example 7

Trioellitic anhydride - ^ - chloride and ρ, ρ ¹ »methylenebis (aniline were mixed with one another in equimolar proportions and converted into a solution containing about 33% pesticides with Ν, ϊϊ-dimethylacetamide. The mixture was added in about 45 minutes at an initial temperature of about 5 - 10 ⁰ C, which rose during the addition to 50 ⁰ C and was maintained at this value by means of a kuhi-bathing is carried out after the exothermic reaction, the reaction mixture was approximately 2 to 2 1/2 hours at 50 ^0th C. and then allowed to cool slowly in about 1 to 2 hours to 30 ^° C. The solution was pressed under pressure into circulating water (about 4 parts of water per part of solution) which was agitated vigorously.

The precipitated solids were collected in a net, transferred to a vessel filled with water, and subjected to several soaking treatments therein until the drain was neutral and its refractive index was about 1.33 or that of pure water Temperature of 49-149 ⁰ C (120-300 ⁰ P) dried. Solutions in a solvent mixture of 2 parts of N-methylpyrrol.idön and 1 part of N ₉ N-dimethylacetamide with a pesticide content of 20-35 Grew .- # were then prepared from the dry precipitate.

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This polyamide solution was very useful for making a pile β suitable, deeeen properties those of Pilsen from the Polyamide according to Example 2 corresponded. In the procedure described above for the production of a polyanide solution the hydrogen chloride was practically completely removed by the water washes described. That way it became a very well suited solution for the production of wire covers according to the Procedure described in Example 1 obtained.

Example 8

A polyamide has been treated to improve its solution properties. The polyamide was prepared from a mixture of 842.28 g of the 4-acid chloride of Trimellithaäureanhydrids and 792.95 g of p.p'-OacybisCanilin) prepared to about 3525 ml Ν, Ν-dimethylformamide at about 14 ⁰ C within about 15 Hinuten were admitted. The reaction temperature rose to about 55 ° C. Then about 1175 πα Ν, Ν-dimethylacetamide was added and the reaction mixture was stirred for about 4 hours at about 50 ⁰ C. The viscosity of the product then obtained was 150 poises.

A portion of the solution was poured into a large excess of water, in which it coagulated into yellow threads. the Threads were washed with water several times, over eight soaked in water, drained and dried in a stream of air at room temperature. The dry threads were in N, Ii-Di me thy If orma ml d to a solution with a fatty substance

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15 * and a viscosity of 30 poise

Another part of the solution (about 86 g) was about Poured 1 1 1/2 η KOT (in water), whereby a precipitate of white threads forms. After leaving it in for 1 ~ 3 hours The threads were removed from the medium, washed with water and soaked in 1/2 η HCl (in water) for about 1 hour washed with water, left in water overnight, drained and dried in a stream of air at room temperature. The dry threads were in Ν, Ν-dimethylformamide in a solution with a solids content of 15 # and converted to a viscosity of 0.6 poise. A second 35 # solids solution in the same solvent had a viscosity of 100 poise.

The 15 5 * solutions containing 35 1> solids were

34f _o

Applied to copper plates and baked at 6Θ & C for 2 minutes. This resulted in clear, tough coatings that could be subjected to a bending test on a 3.2 mm (1/8 inch)

• Well

Thorn and an impact strength test with 181 cm.kg/on the bend when you stood up on a flat surface.

The above results show that the solubility properties of the polyamide prepared as described above by treatment with KOH and HCl. Before the

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Treatment contained the polyamide solution 15% solids and exhibited a viscosity of 30 poise. After the polyamide had been treated, the solution had a Fe et material content of $ 15> a viscosity of 0.6 poise, so that the considerable reduction in viscosity from 30 to 0.6 poise was achieved. Nevertheless, like the solution with a solids content of 35 ° , this solution formed clear-looking coatings which showed good flexibility and good values in the impact resistance test.

In the context of the present invention, protection for the soluble, uncured polyamides and their production is not applied. However, the description of these polyamides and their production is considered necessary for the full disclosure of the invention, since they are indispensable as starting materials for the process according to the invention and have not been described so far.

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Claims (2)

Claims sasaasssassssssasss38883ssuss 1. Electrical coated with a dielectric Conductor, characterized in that the overbend is an infusible one which is insoluble in organic polar solvents PolyamidimidharB is composed essentially of repeating units of the formula ■ HN -— C -Cu NO wherein R represents a divalent aromatic group 2. Electrical conductor according to claim 1, characterized gekenuceic ^ et that R In the recurring units of the resin an oxy-bis-phenylene «or methylene-bis-phenylene group beda: tfc _o 'U 5,>■■>H'