DE1494537B1 - Varnishes containing dyes for electrical conductors based on terephthalic acid polyester - Google Patents

Description

In order to better identify multi-phase windings, they are colored as is known, their individual insulated electrical conductors. The coloring of the Isolation layers were used for the first time as the so-called polyurethane varnishes would be introduced into practice, as the insulating layers produced with these lacquers could be burned in with previously not customary low temperatures and the insulating material base had only a slight intrinsic color. By then you had worked through the individual phases Colored around spinning 'and this working method also for all those areas of application where the use of polyurethane enamel insulation is inappropriate is, especially in the manufacture of armature windings with wires of larger dimensions. While the wires are insulated with polyurethane varnish - not least because of their easy solderability - very quickly introduced to the low-voltage technology, The engine manufacturing industry soon rejected this insulation because it was under mechanical and electrical voltage tends to form hairline cracks and the hairline cracks can also occur in the impregnating varnish. Also, let heat shock resistance and Aging resistance of this lacquer insulation at temperatures above 130 "C increases to be desired.

For the motor winding sector, in steadily increasing proportions of conductors with insulation based on terephthalic acid polyester used. So far, however, these isolations have only been used for this purpose The only color available that varies between light brown and dark brown. This dark shade was very close to what it took to cure the insulation layer high baking temperature. It is therefore unimportant whether this terephthalate insulation Hardening accelerators contain z. B. in the form of organometallic compounds or present as isocyanates.

Incidentally, these polyterephthalate resins corresponded to with darker The inherent color also means the heat shock resistance at the temperatures required in practice of 180 ° C does not meet the requirements. The previously known insulated conductors with insulating layers made of polyesters based on terephthalic acid and / or isophthalic acid with a and polyhydric alcohols, the accelerators or curing catalysts, such as organometallic Compounds, butyl titanate or aluminum alcoholate and / or other compounds, such as isocyanates, etc., were the object of the invention not fair.

The same applies to wire lacquers based on a polyester, stabilized die or polyisocyanates and soluble metal compounds. in which as a metal compound chlorides or compounds with organic acids or organic Metal complex compounds are present.

The object on which the invention is based is the delivery of electrical conductors with insulation based on terephthalic acid polyester resins, those with insulation with a higher throughput speed and / or with others Temperatures than before can take place and at which also the isolation of the Head has a lower intrinsic color, shows no hairline cracks in the salt bath and is heat shock resistant above 175 "C. In particular, it is made by the invention possible, with choice of suitable dyes a luminous one. colorfast insulation to achieve what is due to the low curing temperatures and the resulting lower intrinsic color is due. The luminous, color-fast insulation of the Invention corresponds to the desire in practice, according to which the fill factor unfavorable influencing spinning of the conductors should be avoided and thus the motor size can be reduced. Finally, it is also possible according to the invention that optimal electrical and mechanical properties of the insulation layer To determine the calculation.

The invention relates to paints containing dyes for electrical purposes Ladder based on reaction products of terephthalic acid polyesters and Butyl titanate and optionally also metal alcoholates, the polyesters consist of reaction products of terephthalic acid and di- or trihydric alcohols, dissolved in solvents customary for polyester wire enamels. Draw these varnishes is characterized by it. that the terephthalic acid polyester, the butyl titanate and the metal alcoholates Contain in such amounts that at least 500 / (1 of the analytically determinable hydroxyl equivalent of the terephthalic acid polyester and 300 / o thereof are saturated by butyl titanate alone are.

They are wire enamels based on polybenzenedicarboxylic acid esters known, in their production, the esterification under very specific conditions must be carried out and the polyester must be one before dissolving To be subjected to extraction. These varnishes contain 1 to 15 after dissolution Percentage by weight of organometallic compounds of elements of group III or IV of the periodic table.

For the first time, the invention makes paints for electrical conductors Supplied that contain no stabilized die or polyisocyanates and no chlorides or Contain metal compounds with organic acids and also as an acid component contain only terephthalic acid. In making the paints of the invention There is also no need for extraction before dissolving.

It was not to be foreseen. that the union of such valuable properties like improved throughput speed at more favorable temperatures, lower ones Natural color, no hairline cracks in the salt bath, heat shock resistance of 1800C and the possibility of color-fast insulation in the case of the composite according to the invention Lacquers by coordinating the proportions of incorporated metal alcoholates, based on the analytically determinable hydroxyl equivalent of the polyterephthalic acid resin, could be achieved.

According to one embodiment of the invention, lie in the polyester resin converted polymers of butyl titanate, in particular die or trimers, before.

According to a further embodiment, the insulation contains the following Colorants, preferably in amounts up to 0.5 percent by weight: 0.5010 Zaponfast yellow G (Color Index, 2nd edition, 1956, Vol. 2, p. 2827, C. 1. 48 045), 0.50 / o astraphloxin G Conc. Type 8005 (Color Index, 2nd edition, 1956, vol. 1, p. 1632, C. 1. 48 070), 0.2U / o Irisolechtviolett BBN (Color Index, 2nd edition, 1956, Vol. 2, p. 2870, C. 1.

60 725), 0.4% patent blue V extr. conc. (Farhstotftabellen by Gustav Schultz, 7th edition, vol. 1, 1931, p. 349, no. 826), 0.166% patent blue V extr. Conc. + 0.334% zapon yellow G = green With the exception of ZapongelbG, the dyes listed are those that have so far hardly been used for insulation made of polyterephthalate resin lacquers, that is, they were uncommon.

As has been proven, the dyes mentioned have this property to increase the paint viscosity when added in the specified small amounts, a phenomenon that is probably due to an implementation. This one increase the reaction causing the paint viscosity leads to the dye on immersion does not bleed into alcohols, aromatics and aliphatics from the finished insulation, d. This means that the solvents and thus also the impregnating varnishes do not discolour. The following Test results confirm the mentioned increase in viscosity.

1. The solution of a polyterephthalate resin with an equivalent weight out of 450 was with an equivalent weight of 50U / n Amount by weight of polymeric butyl titanate added. Table 1 below illustrates the increase in viscosity when small amounts of dyes are added to the paint.

Panel I. DIN 53 211 Solid resin (mmDusc) in the paint color in the paint viscosity (Seconds) 30% without dye 292 30% 0.5% Zapon fast yellow G 386 30% 0.5% astraphloxin G conc. 393 Type 8005 39% 0.2% Irisol fast violet BBN 307 30% 0.166% patent blue V extr. conc. 416 O, 3340 / o Zaponechtgelb G 30% 0.40 / 0 patent blue V 330 extr. conc.

2. A solution of a polyterephthalate resin with an equivalent weight of 750 was again mixed with 50% of the equivalent amount of butyl titanate polymer. Table II lists the results: Table II Solid resin Viskosit @ t in the lacquer dye in the lacquer (seconds) 3O01o without dye 76 30%, 0.5% Zaponfast yellow G 76 30% 0.2% Irisol fast violet BBN 81 The mechanical properties of the insulated conductor depend on the ratio of dihydric to trihydric alcohol. The higher the proportion of trihydric alcohol, the more inelastic the corresponding wire enamel film. For this reason, the cross-sections of the conductor to be coated must be reduced as the proportion of trihydric alcohol increases.

The requirement for butyl titanate and / or metal allotolates must be calculated are from the hydroxyl @ equivalent of the terephthalic acid ester and the valence of butyl titanate or metal alcoholate. The lower the hydroxyl equivalent of the ester, the higher the weight requirement for butyl titanate and / or metal alcoholate while reducing the hardening temperature or increasing the hardening speed. It is expedient to use butyl titanate and metal alcoholates in a manner known per se to stabilize or reduce their responsiveness. The calculated Quantities can be added to the melt or to the solution of the polyterephthalate resin will. The conductor is isolated from the solution in a manner known per se.

The optimal properties of the conductor are correct if the highest take-off speed or the lowest temperature at which the Ladder in the salt bath when bending to your own diameter, no hairline formation shows more and under these conditions also insulates a perfect thermal shock at 180 C, regardless of whether it is colored or colorless isolated is. Taking the measures of the invention as a basis, it can easily be determined how to achieve these optimal properties.

The insulated conductor shows in when immersed at 50 C for 30 minutes aliphatic, aromatic and alcoholic solvents do not soften. The pencil hardness the insulated conductor drops when treated in the same way in acetone at room temperatures by no more than one degree of hardness.

The following examples illustrate the invention.

Example @ A terephthalic acid ester was obtained by transesterification of Dimethyl terephthalate made with glycerine and glycol, which has an excess Contained hydroxyl.

The following were used: 582 g of dimethyl terephthalate .... 6 COOH 124 g of glycol ... ... ... 4 OH 110.5 g glycerine 3, 60H After the methanol has been completely removed the yield is 623.5 g, which accounts for 1.6 mol of OH.

Melting point: 48 ° C; theoretical equivalent weight: 389; analytically determined: 395.

The melting point of the ester was determined by further temperature treatment at about 220 ° C increased to 82 ° C, this creates cleavage products that are practically are free of methanol. The analytically determinable equivalent weight of the ester rose to 550.

The ester thus obtained was m a solvent mixture of the same Parts of a phenol and an aromatic hydrocarbon which is liquid at room temperature dissolved and the required amount of butyl titanate calculated from the equivalent weight to the solution of the ester: added, with a partial reaction already occurring, which increases both in the form of turbidity and an increase in viscosity recognize there. One now heats up 100 C for 30 minutes, in this way, storage-stable precondensates of butyl titanate and terephthalic acid ester were obtained, which are suitable for insulating electrical conductors.

Wire enamel 1 a): 550 g ester, dissolved in cresol solvent naphtha (1: 1), 95g trimeric butyl titanate, corresponding to 100% crosslinking.

Wire enamel 1 b): 550 g ester, dissolved in creso-solvent naphtha (1: 1), 85 g of monomeric butyl titanate, corresponding to 100% crosslinking.

The reaction product that arises on the ladder is for ladder of 1 to 0.50 mm in diameter too brittle in terms of its mechanical properties however, it is suitable for conductors with a diameter of 0.30 mm and for those with a smaller cross-section (see table 1).

Example 2 The procedure was analogous to Example I, but the proportion of glycol increased: 582 g dimethyl terephthalate ... 6.0 COOH 136.4 g glycol .... .. .. 4AOH 92.3 g glycerin. . . 3.0 OH The theoretical yield of ester of 619 g corresponded to one Equivalent weight of 442, the following equivalent weights were determined analytically Depending on the melting point: F. = 50 C equivalent weight 417, F. = 68 C equivalent weight 465, F. = 81 C equivalent weight 480.

Wire enamel 2a): 480 g ester. dissolved as 1 a), 95g trimeric butyl titanate, Corresponding 1000 networking.

Wire enamel 2 b): 480 g of ester, dissolved as 1 a), 72 g of trimeric butyl titanate. Corresponding to 75.70 cross-linking.

Wire enamel 2 c): 480g ester. dissolved as 1 a), 85 g of butyl titanate. monomeric. corresponds to 1000 of the above networking.

Wire enamel 2d): 480 g of ester, dissolved as in 1 a).

62.4 g butyl titanate, monomeric, corresp.

73.5% networking.

The mechanical properties of these insulating compounds are sufficient for wires 1 mm diameter straight, but not for larger cross-sections (see table II).

Example 3 Esters were prepared from dimethyl terephthalate, whose proportion of glycol was increased, while the hydroxyl excess remained the same. Hydroxy equivalent of the ester with a melting point of 82 C: 450 g.

Wire enamel 3 a): 450 g ester, dissolved as 1 a), 95 g butyl titanate, trimer, corresponding to 100% networking.

Wire enamel 3 b): 450 g ester, dissolved as 1 a), 48 g butyl titanate, trimer, corresponding to 50.5% crosslinking.

The mechanical properties are such that they are used to isolate Ladders with a diameter of more than 1 mm are suitable (see Table III for results).

Example 4 The proportion of glycol corresponded to Example 3. the proportion of free OH groups was reduced.

Hydroxyl equivalent weight of the ester: 750; Melting point: 82 C.

Wire enamel 4 a): 750 g of ester, dissolved as I a).

95g butyl titanate, trimer (crosslinking 100%).

Wire enamel 4 b): 750 g of ester, dissolved as 1 a).

50g butyl titanate, trimer (crosslinking 52.6%), wire enamel 4c): 750 g Ester, dissolved as 1 a).

37.3 g of butyl titanate. trimer (crosslinking 39.2%), wire enamel 4d): 750 g ester, dissolved as 1 a).

85 g of butyl titanate. monomeric (crosslinking 100%).

Mechanically sufficient for wires over 1 mm in diameter (results see Table IV).

Example 5 Instead of exclusively butyl titanate, there was butyl aluminate used.

Wire enamel 5a): 550 g of ester according to Example 1, dissolved as 1 a), 36.6 g butyl titanate. trimer (crosslinking 38.5), 50 g butyl aluminate (crosslinking 61.5%).

The results of this combination are shown in Table 1. Tested was in turn on ladders with a diameter of 0.30 mm.

Example 6 For the precondensation between the terephthalic acid polyester and butyl titanate speaks besides the haze. which occurs temporarily and when heated disappears to 60 to 100 C, the following change in viscosity: 1,300; 0 solution of the ester according to example 1 (according to DIN 53211) .. 82 seconds 2. After adding 50% the equivalent amount of butyl titanate stabilized ........... 112 seconds 3. After Warming to 100 C for 30 minutes .. 125 seconds The precondensate is after 3 months of storage at a temperature of -8 to +15 "C in viscosity and Appearance unchanged.

The 300 / own solution with 82 seconds (viscosity) will be 5001o the equivalent amount of butyl titanate added, the viscosity increases to 120 seconds and after 30 minutes at 100 ° C. the storage stability has increased to 128 seconds is good.

The insulation of the conductors was done according to the usual practice Methods. The conductors were made in order to achieve the prescribed layer thickness required number of swipes through a bath of the dissolved precondensate drawn and each layer burned in for itself. The stripping is done by means of Felts or nozzles, the furnace shafts can be stored horizontally or vertically.

In the following tables, column 1 is the designation of the Wire enamels listed according to the examples. In column 2 is the withdrawal speed of the conductor to be insulated through an oven of 2.5 m length at 460 ° C in meters played per minute. Column 3 shows the pencil hardness. split 4 gives the pencil hardness of the insulating layer after 30 minutes of treatment at 50 ° C in the listed media (fuel, benzene, gasoline, acetone). From column 5 is to see the color of the insulation. Column 6 (salt bath) gives the assessment the bending test of the insulated conductor in a 0.5 "/" igeu saline solution is the salt bath at one pole, but the conductor at the opposite pole of I (H) volts DC voltage connected. Column 7 (thermal shock 180 C, single wire diameter); a curl of a single wire diameter and 10 cm in length is used for the duration exposed to a temperature of 180 ° C for 60 minutes. From column 7 is the assessment is evident.

Column 8 corresponds to column 7, but with the wire doubled Wire diameter was wound.

The tables show that with the combinations according to the invention significant technical advantages compared to the previous commercially available products can be achieved. These advantages lie primarily in the excellent heat shock resistance at 180: C, while at the same time behaving perfectly in the salt bath, at an elevated temperature Take-off speed and at least partially with a greater surface hardness.

The problem of coloring polyterephthalate paints is so old like the paints themselves. It should not be denied that since it became known these lacquers no colored polyester lacquer of sufficient quality on the market was. From this fact it can be seen how difficult polyester paints have been to be stained colourfast with soluble dyes.

It should only be mentioned that at times even pigmented terephthalate lacquers were on the market that contained up to 20 "/" titanium dioxide and the corresponding lacquer technology exhibited reduced properties.

The invention was therefore based on the object of developing a paint which develops as little intrinsic color as possible at the required high baking temperature, So not like the well-known polyterephthalate lacquers turned dark brown when stoving, at the same time dyes had to be found that match those contained in the paint Solvent compatible, d. H. were readily soluble and color fast.

In addition, it was required. that the dyes even after a long time Storage of the paint in metal containers was allowed to be stable and also temperature-resistant had to be in order to achieve a good visual effect in the smallest possible quantities.

It is known from "Farbe und Lacke", 1955, Heft2, p. 66, butyl titanate in amounts of 1 to 10010 resins of various kinds to be added, which are also used as electrical insulating varnishes Find use. It is also stated here that butyl titanates react with resins, containing a hydroxyl group. It is true that an improvement is also certain electrical properties of paints spoken by the addition of butyl titanate, However, alkyd, maprenal, Desmodur-Desmophen and epoxy resins are mentioned and placed side by side at the same time. It is also expressly pointed out that that one disadvantage of adding butyl titanate to these binders is the resulting is a yellowish tone that increases with the amount of butyl titanate. The procedure of the invention makes it for the selected special case of terephthalic acid polyester possible to accelerate the drying so that the polyester, under the action at higher temperatures shows a strong brown color, at significantly lower temperatures Temperatures can be dried. It develops so little color of its own that it becomes possible to dye the solution of this polyester so that it is colored flawless enamelled wires with luminous, colourfast insulation can be achieved.

The information in "Angewandte Chemie", 1952, p. 538, is only it can be seen that butyl titanate is a good crosslinking agent for those containing hydroxyl groups Polyester is. According to the résumé of French patent specification 1 234 466, a Esters of terephthalic acid with 2 to 60 percent by weight isopropyl titanate, butyl titanate or 2-ethylhexyl titanate are mixed. Here is from a selection in the spirit of the Invention out of the question. In isopropyl titanate there is 16.9 weight percent effective titanium contained, but in the 2-ethylhexyl titanate only 9.46% titanium. Totally independent of these differences in titanium content, according to the French patent but all three titanates are equally effective. The assignment of effective titanium in Form of monomeric or polymeric butyl titanate for the number of free OH groups of terephthalic acid polyester, expressed as OH equivalent, is the basis of the method of the invention. The addition of butyl titanate should not change the color cause, but are kept so low according to the invention that practically none Self-coloring occurs. The staining is then carried out with soluble dyes.

If in the reference "Industrie-Lackierbetrieb", 1959, p. 173, right column, it is mentioned that Irisol fast violet BBN can be used for coloring Wire enamels based on silicone have already been used, so there is none here See reference to the invention. The use of a soluble dye in a silicone varnish is relatively unproblematic, with the exception of temperature resistance no special requirements have to be placed on the dye. Silicone varnishes are soluble in normal solvents such as aromatics and ketones. Your chemical By nature they are neutral, and they also dry without yellowing.

So you can paint the purest white with them produce, which do not yellow even with long-term exposure to temperatures of up to 400 ° C. In the Coloring of silicone varnishes with soluble dyes can therefore be due to the chemical Neutrality of the binder no reaction take place as it is according to the invention to the esters of terephthalic acid crosslinked in the stoichiometric ratio with butyl titanate and the soluble dyes takes place and is clearly recognizable by a Expresses increase in viscosity.

Silicone varnishes are many times higher in price than the varnishes based on terephthalic acid polyesters for the purposes of the invention.

In addition, silicone varnishes have the disadvantage that at Processing with Varnish solvents and impregnating varnishes cause a significant drop in surface hardness Purchase must be taken #. In the citation "Industrial paint shop" (op. a. O.) shows this drop in hardness in the table shown.

Only through the process of precondensation between the hydroxyl-containing Ester and the butyl titanate and the further reaction with the dye accordingly According to the invention, a color-fast coating could be achieved. Nobody had to Impairment of the optimal electrical and mechanical properties of the insulating layer be accepted.

Table I. 1 2 3 4 5 6 7 8 Take-off 30 minutes at 50 ° C in single duplicates geachwindig- hardness color salt bath diameter diameter Shock shock fuel benzene gasoline acetone 180 ° C 180 ° C la 16 m 4 H 4H 4H 4H 3H light yellow good 2 Platzer good 1a 18 m 4H 4H 4H 4H 3H light yellow good good good 1b 16 m 4H 4H 4H 4H 3H light yellow good 4 Platzer good Ib 18m 4H 4H 4H 4H 3H light yellow good good good 5a 16m 3H 3H 3H 3H 2H light yellow good 4 burst good 5a 18m 3H 3H 3H 3H 2H light yellow good good good Wire thickness: 0.3mm.

Table II 1 2 3 4 5 6 7 8 Take-off 30 minutes at 50 ° C in single duplicates Lacquer geachwindig- hardness @ @ @ color salt bath diameter diameter ability shock shock Gasoline benzene gasoline acetone shock shock 180 ° C 180 ° C 2a 8m 2 to 3H 2 to 3H 2 to 3H 2 to 3H H to 2H yellow good 2 bursts good 2b 8m 2 to 3H 2 to 3H 2 to 3H 2 to 3H H to 2H yellow good 1 burst good 2c @ 8m 2bis3H 2bis3H 2bis3H 2bis3H Hbis2H Yellow good 5 bursts good 2d 8m 2 to 3H 2 to 3H 2 to 3H 2 to 3H H to 2H yellow good 3 bursts good Commercial 5 m HHHHF brown well destroys many usual burst Paint 6m HHHH 3B brown cracked 3 bursts good Wire thickness: 1 mm Table III 1 2 3 4 5 6 7 8 Take-off 30 minutes at 50 ° C in single duplicates Paint speed hardness color salt bath diameter diameter Shock shock ability fuel benzene gasoline accton 180 ° C 180 ° C 3a 9m 2H 2H H 2H 2H H light yellow good 1 Platzeri good 3b 8m HHHHF light yellow good 4 Platzer good Commercial 5m HHHHF brown well destroys many usual burst Paint 6m HHHH 3B brown cracked 3 bursts good Wire thickness: 1 mm Table IV 1 2 3 4 5 6 7 8 Take-off 30 minutes at 50 ° C in single duplicates Paint speed- hardness diameter diameter Farge salt bath shock shock ability fuel benzene gasoline accton 180 ° C 180 ° C 4a 8 m H to 2H H to 2H H to 2H H to 2H F light yellow good 1 burst good 4b 8m HHHHB light yellow good 3 burst good 4c 7 m HHHHB yellow good 25 places 5 places 4d 8 HHHHHF light yellow good good good Commercial 5m HHHHF Braun gut destroys many usual burst Paint 6m HHFH 3B brown cracked 3 bursts good Wire thickness: 1 mm.

Claims (1)

Claim: Paints containing dyes for electrical conductors based on reaction products of terephthalic acid polyesters and butyl titanate and optionally also metal alcoholates, the polyesters being made from reaction products consist of terephthalic acid and di- and / or trihydric alcohols, dissolved in for Poly ester wire enamels customary solvents, characterized in that the terephthalic acid polyester contain the butyl titanate and the metal alcoholates in such amounts that at least 5001o of the analytically determinable hydroxyl equivalent of the terephthalic acid polyester and 30,010 of these are saturated by butyl titanate alone.