SE438320B - LACKS, INCLUDING A POLYESTER OR POLYESTERIMID RESIN WITH CYCLIC LACTAM GROUPS - Google Patents

Description

Polyester or polyestercrimide resins which are soluble in water have already been prepared by polycondensation of polycarboxylic acids with polyalcohols, such as diols or triols, leaving in the reaction mixture or at the end of the reaction time. In the reaction, an excess of carboxyl groups is added, which are then bound as salt by means of ammonia or an amine, which makes the resin soluble or partially soluble in water. However, these resins have high acid numbers of the order of H0-100. The presence of carboxyl groups is unfavorable for good adhesion to a metal substrate when used for coating wire or sheet metal. Furthermore, the amount of amine required for salt formation with the carboxyl groups is relatively large, and the commonly used amines, especially for the preparation of polyesterimide resins, are expensive products. The present invention has for its object to eliminate the various aforesaid the disadvantages and to provide paints based on polyester and / or polyesterimide resins which are dissolved in low or not at all polluting solvents, and preferably then partially aqueous, but with low acid numbers, so that only a small amount amine is required for their salt formation, so as to enable the obtaining of very adhesive coatings on a metal substrate, and which further exhibit physical and electrical properties at least equivalent to those of water-insoluble polyester and / or polyesterimide resins.

The paints according to the invention, of the type comprising a polyester and / or polyesterimide resin, which are prepared by polyesterification of at least one polycarboxylic acid containing at least one five-membered, cyclic lactam, or a compound capable of giving such an acid, with at least one polyalcohol, characterized in that the solvents contain an organic solvent which is low or non-polluting, preferably in admixture with water when it is miscible therewith. It has been found in practice that in contrast to polyester resins and polyesterimide resins, in which the polycarboxylic acid consists at least in part of terephthalic acid or isophthalic acid, those polyester resins and polyesterimide resins in which the polycarboxylic acid contains at least one five-membered, cyclic acid tam, a considerably superior tendency for solution in water or in water-miscible solvents. The paints according to the invention furthermore suitably have the following characteristic properties: - The solvent constitutes a mixture of water and an organic, cooperating solvent which at least in part consists of dimethylaminoethanol.

- The solvent further contains dimctylformamide.

- The solvent further contains ethyl glycol.

- The solvent further contains N-methylpyrrolidone.

The solvent constitutes an anhydrous solvent of LO the group comprising at least one alkyl ester and one ester or ether of glycol.

The polycarboxylic acid containing at least one five-membered cyclic lactam is a diacid lactam, produced by the condensation of about 2 moles of itaconic acid, or one of its substituted derivatives or esters, with 1 mole of a diamine, which at each end of its chain contains a primary amino group, and the weight fraction of the diacid lactam in the reaction mixture subjected to the polyesterification is between 30 and 90% by weight, preferably then about 70% by weight. The polycarboxylic acid containing at least one five-membered cyclic lactam is a diacid, produced by condensation in substantially equimolar proportions of itaconic acid or of one of its substituted derivatives or of its esters, with one amino acid, preferably with glycoll. They further contain a polyesterimide resin, prepared by polyesterification of a diacid diimide, obtained by condensing about 2 moles of an aromatic polyacid having at least three carboxyl groups, two groups of which are in the ortho position, or a compound capable of giving such an acid, with 1 mole of a di- iÛ amine, which contains a primary amino group at each end of its chain.

The proportion of the diacid lactam in the reaction mixture subjected to the polyesterification is between 10 and H0% by weight, preferably then about 50% by weight, and that of the diacid diamide 5 is between 20 and 80% by weight, preferably then about H0% by weight.

The polyesterification is carried out with a mixture of at least one diol and at least one triol, the amount of diol in the reaction mixture being between 5 and 20% by weight, preferably about 10% by weight, and the triol constituting between 10 and 40% by weight. -........_....__.._._.... ... ~ _ _ ..- 10 20 I nas with the abbreviation TBT) in 20 parts xylene. 1806149-6, preferably then about 20% by weight.

The polyalcohol is at least a part of trihydroxyethyl isocyanurate. The following examples describe processes for the production of polyester resins or polyesterimide resins and the preparation of lacquers according to the invention, as well as the painting of electrical wire with such lacquers, as well as the physical, mechanical, chemical, thermal and electrical properties of the obtained the varnishes on the threads. In Example 1 In a flask equipped with a stirrer, Vigreux column and thermometer, and under a nitrogen atmosphere, 220.6 parts by weight of N-methylpyrrolidone (hereinafter referred to by the abbreviation as NMP) are charged, and then with stirring 158, 8 parts by weight of methylenedianiline (hereinafter referred to by the abbreviation MDA), 48.85 parts by weight of monoethylene glycol and 205.6 parts by weight of trihydroxyethyl isocyanurate (hereinafter referred to by the abbreviation THEIC). calculated by weight. The mixture is heated for dissolution to .100 ° C. Then 182.15 parts of itaconic acid, 138.8 parts of MDA, 269 parts of trimellitic anhydride (hereinafter referred to as the abbreviation TMA) and 21 parts of tetrabutyl titanate are added. All parts are also in the following (which acts as a crosslinking agent and hereinafter referred to as - The heating is resumed while raising the temperature by 20 ° C per hour to 22o ° c. 100.8 parts of water are removed.

The condensation of the itaconic acid with the methylenedianiline takes place / +1 H2 3- (K \\ cnz _ // \\ N52 _ “_ \ __ CH CH - CO CO _ I 2. 'f O 2" K _ // __ __ \\ HOZC 7. (disyralactam) + 2H2O Distillation of water begins at 13000. Total according to the reaction scheme: C32 CO2 H '(1 -ncoz fi ià (I LO L5 7806149-6 The resin thus obtained can be cast to obtain a hard and brittle material, at a content of 80% by weight in NMP. The acid number of the resin is 12, and its drop point according to ubbeinode is 120%. This resin can be brined in solution as follows: 250 parts of the resin prepared according to the above 45 parts dimethylformamide (DMF) 50 parts of 2-dimethylaminoethanol (DMAE) 115 parts of methylene oxide (Mc) 150 parts of water 2 parts of crosslinking agent, ammonium lactate titanate (marketed by Du Pont de Nemours under the trade name TyzorLa) 10 parts of surfactant known under trade name Noramox CV15 (this product is intended to provide an improved surface when used as a varnish) 512 parts resin obtained lles with H0% active material. Its viscosity is 550 mPas at 20 ° C.

Analogous resins can be prepared by using as diamine for condensation with the itaconic acid another diamine, such as methylenedianiline, or preferably an aromatic diamine, such as diaminodiphenyl ketone, diaminodiphenyl sulfone, diaminodiphenyl ether, benzidine, etc. Similarly, other diols or propylene glycol can be used. pentaerythritol, etc., and other polycarboxylic acids, such as pyromellitic anhydride.

Example 2 In a flask with a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 20 parts of NMP and -88.85 parts of monoethylene glycol are charged. The mixture is heated with stirring to 10,000, after which 138.8 parts of MDA, 182.15 parts of itaconic acid, 205.6 parts of THEIC and 17.65 parts of TBT in 20 parts of xylene are added.

The temperature is gradually satisfied with 2000 per hour to 21000.

The distillation of the water begins at 150 ° C, and the amount of water eliminated is 50.8 parts. The mixture is cooled to 18,000, and 86.9 parts of monoethylene glycol are added. to 15 ° C, and 269 parts of TMA and 20 parts of xylene are added.

Heating is resumed at 2000 per hour to about 18500. The mixture is cooled The temperature is lowered the amount of water evaporated is about 17 parts. to 130 ° C and is added with 138.2 parts of MDA and 20 parts of xylene, then heating is disconnected with a temperature increase of 2006 per hour to 210 ~ 220 ° C. The amount of water eliminated is 33.6 parts. The resin thus obtained can be poured to obtain a hard and brittle material with 89% content, an acid number of lo and a drop point: according to ubbelheae ev lu5 ° Q.

This resin can likewise be dissolved in the following manner: 1.5 parts of the resin prepared according to the above 25.1 parts of DMF 12 parts of DMAE - parts of water 2U0 parts of lacquer with 50% of active material.

Its viscosity is 800 mPas at 2000.

'Example 3' In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 116.5 parts of NMP are charged and with stirring U5.95 parts of monoethylene glycol. The mixture is cooled to 100 ° C, and 158.80 parts of MDA, 182.15 parts of itaconic acid, 205.60 parts of THEIC and 8 parts of TBT in 20 parts of xylene are added. The temperature is raised to l95 ° C by 20 ° C per hour. The distillation of water begins at 130 DEG C. and the total amount of water evaporated is 50 parts. The whole kylee to 18,000, one & 90 parts of monoethylene glycol and 10 parts of NMP are added. When the temperature has dropped to 110 ° C, 138.80 parts of MDA and 269 parts of TMA are added.

Heating is resumed at 20 ° C per hour to 22000. Distillation begins at 0 ° C and the total amount of water evaporated is 50, H parts. . The resin thus obtained can be cast to obtain a solid and brittle material at 80% content, with an acid value of 12 and an Ubbelhode drop point of 117 ° C.

This resin can also be dissolved in the following manner: ll2.5 parts of the resin prepared according to the above 31.5 parts DMAE l§§_¿ parts water 300 parts of a lacquer with 30% active material.

Its viscosity is about 150 mPas at 20 ° C.

Example H 220.6 parts of NMP and δ 8.85 parts of monoethylene glycol are charged to a flask with a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer. The mixture is heated with stirring to 10,000 and added with 158.8 parts of MDA, 182.15 parts of itaconic acid, 205.60 parts of THEIC and 3 parts of TBT in 20 parts of xylene, and 5 parts of cerium octoate, 0.15 parts of zinc acetate, 158. 8 parts MDA and 269 parts TMA. The temperature is adjusted to 22o ° c at 2o ° c per hour.

The distillation began at 13,000, and the total amount of water evaporated is 100.8 parts.

The resin thus obtained can be cast to obtain a hard and brittle material at 80% content and with an acid number of 16 and an Ubbelhode droplet point at 11 ° C. This resin can likewise be dissolved in the following manner: 180 parts of the resin prepared as above 32.25 parts DMF 54_ parts DMAE 21.60 parts monoethylene glycol U2, 15 parts water 7.20 parts surfactant Dísperbyk from Société BYK Mallinckrodt 367.2 parts of a resin with H0% active material.

Its viscosity is about 800 mPas at 20 ° C.

B-180 parts of the resin according to Example H 52.30 parts DMF 21.60 parts DMAE 32.40 parts methyl glycol 93.60 parts water 1, uu parts crosslinking agent with Iyzer LA 7.20 parts surfactant Noramox CV15 368.8 parts of a lacquer with H0% active material.

Its viscosity is 550 mPas at 2000.

Example 5 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 220.6 parts of NMP and N8.85 parts (0.787 mol) of monoethylene glycol) are charged. The mixture is heated with stirring to 100 ° C and added with 138.8 parts (0.7 moles) of MDA, 182.15 parts (1.0 moles) of itaconic acid, 205.60 parts (0.778 moles) of THEIC and 3 parts of TBT in 20 parts xylene, and 5 parts cerium octoate, 0.15 parts zinc acetate, 158.8 parts (0.7 mol) MDA and 269 parts (1, M flour) TMA. The temperature is adjusted to 22o ° c at 2o ° c per hour. The distillation begins at 15,000, and the total amount of water evaporated is 100.8 parts. The reaction is stopped when the Ubbel head is 12000. The mixture is cooled, and 195.85 parts of DMF are added, at 15000 195.85 parts of 15 ° C 130.55 parts of DMAE, at 115 ° C 565.75 parts of the drop point at 17 °. c herring methylglycol, at water, and at 6000 8.7 parts of ammonium lactate titanate and H3.5 parts of Noramox CV 15.

A lacquer is obtained with A0% active material and a viscosity of 520 mPas. vid-2000.

Example gel 6 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 212.75 parts of NMP and 58.60 parts (0.94 U mol) of monoethylene glycol are charged. the mixture is heated with stirring to 100 ° C and added with 158.80 parts (0.7 mol) of MDA, 182.15 parts (1.1 mol) of itaconic acid, 16U, 50 parts (0.63 mol) of THEIC and 3 parts of TBT in 20 parts xylene, and 3 parts cerium octoate, 0.15 parts zinc acetate, 138.80 parts (0.7 mol) MDA and 269 parts (1.1 H mol) TMA. The temperature is raised to 22.2 ° C by 2000 per hour. The distillation starts at 13000 and the total amount of water evaporated is 100.8 parts.

The obtained resin can be cast to obtain a hard and brittle material with 80% content, an acid number of 15 and an Ubbelhode drop point of 11000.

This resin can also be brought into solution in the same manner as in Example 1 to obtain a lacquer with A0% active material and a viscosity of 530 mPas at 2000.

Example 7 8 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 225.7 parts of NMP and 52.75 parts (0.85 mol) of monoethylene glycol are charged. The whole is heated with stirring to 10,000 and added with 158.8 parts (0.7 moles) of MDA, 182.15 parts (1.1 moles) of itaconic acid, 222.05 parts (0.85 moles) of THEIC and 5 parts TBT in 20 parts xylene, and 3 parts cerium octoate, 0.15 parts zinc acetate, 138.8 parts (0.7 mol) MDA and 269 parts (1.1 H mol) TMA. The temperature is raised to 22,000 by 2,000 per hour.

Distillation begins at 13000, and the total amount of water evaporated is 100.8 parts. The resin thus obtained can be cast to obtain a hard and brittle product with 80% content, an acid number of 12 and a drop point according to Ubbelhode at 111 ° C.

This resin can also be dissolved in the same way as in Example 1 to obtain a lacquer with H0% active material and with a viscosity of 560 mPas at 20 ° C.

In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 80 parts of NMP and U8.8 parts (0.787 mol) of monoethylene glycol are charged. The mixture is heated with stirring to 9000 and added with 91 parts (0.7 mol) of itaconic acid and then with 52.5 parts (0.7 moles) of glyco carbon. Heating is resumed to 110 ° C, and 205.6 parts (0.787 moles) of THEIC are added.

The whole is heated at about 14,000 until parts of water have been evaporated. As catalyst, 3 parts of a complex of lead phenolate and hexamethylenediamine are added, and then in small portions a mixture of 138.8 parts (0.7 mol) of MDA and 269 parts (1.0 mol) of TMA for an addition time of about 1.5 hours. Towards the end of the addition of MDA and TMA, the mixture is heated to 160 ° C to facilitate stirring, after which the mixture is progressively heated at 2000 per hour to 22000. The amount of water evaporated is 88.2 parts. The reaction is stopped when the resin has an Ubbelhode drop point of 159 ° C, the acid number being 29.

The resin thus prepared is in the form of a hard and brittle product with 90% NMP.

The condensation of the itaconic acid with glycoco o en takes place according to the following reaction scheme: coon / cooH 0112-- c P cH¿- cn | H 1% | I c ena co C112 // o N foï Ã-if; fra-cin coon cnz coon The resin can be diluted as follows: H2.1 parts of the resin prepared as above 20 parts NMP 10 parts DMF 6 parts DMAE 10 parts MG _ïâ parts water 135.1 parts resin with 30% active material. Analog resins can be used using an amino acid other than glycol carbon for the condensation, preferably aliphatic, such as aminopropionic acid, aminocaproic acid, etc.

Example 9 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 2H1, 13 parts of NMP, 78.21 parts (1.26 mol) of monoethylene glycol and 92.09 parts (1 mol) of glycerol are charged, and then with stirring at 60 ° C. 407, H2 parts (2.055 mol) of MDA, 53.0, 71 parts (U, 11 mol) of itaconic acid and 1.1 parts of TBT in 20 parts of xylene. The mixture is heated to 22006 at 20 ° C per hour. The distillation begins at 120 ° C and the total amount of water evaporated is 117.96 parts. The resin thus obtained is 80% in NMP and has a drop point according to Ubbel head at 78 ° C. This resin can be dissolved in the same manner as in Example 1.

Example 10 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer are charged 283.4 parts of NMP and 78.21 parts (1.26 moles) of monoethylene glycol, after which 251, 2U parts (1 ml) are added with stirring at 6000 THEIC, ħ7, U2 parts (2.055 mol) MDA, 554.71 parts (H, ll mol) itaconic acid and 1.3 parts TBT The whole is heated to 22000 at 20 ° C per hour.

The distillation begins at 12,000, and the total amount of water evaporated is 147.96 parts. The resin thus obtained is 80% NMP and has an Ubbelhode drop point at 91 ° C. This resin can be brought into solution in the same manner as in Example 1.

Example 11 In a flask under a nitrogen atmosphere and equipped with a stirrer, Vigreux column and thermometer, 27.9 parts (0, 5 moles) of monoethylene glycol and 20 parts of xylene are charged, after which stirring at 8000 is added. ) THEIC, 75 parts (1 mol) of glycocol, 150 parts (1 mol) of itaconic acid and 1 part of catalyst (complex between lead phenolate and hexamethylenediamine to 25% in cresol), and the mixture is heated to 20,000 at 20 ° C per hour . The distillation starts at 130 ° C and the total amount of water evaporated is 5ü parts. The resin thus obtained has an Ubbelhode drop point at 129 ° C. This resin can be dissolved in the following manner: H0 parts of the resin prepared as above parts DNF parts methyl glycol parts DMAE 56 parts water part Tyzor LA parts Noramox CVl5 LED-J G 106 parts resin with H0% active material.

A copper wire with a diameter of 0.8 mm is lacquered with the solutions described in Examples 1 to 11 with 6 continuous coatings in a vertical furnace with a length of 3.6 m for lacing metal wires and with N heating zones at 210, 530, N60 and 360 ° C.

The following examinations were made of the lacquered wire: Experiment no. 1: Measurement of applied thickness (IEC standard, article U) This is carried out on 5 test pieces with a precision micrometer. First the diameter of the insulated conductor is measured, and then the diameter of the wire after removal of the locomotive layer. The average value of the 5 results is calculated.

Experiment No. 2: Flexibility of the lacquered wire (IEC standard, article 8-1) In Windings are made on mandrels with diameters equal to a whole number of times the normal diameter of the trees, before and after extension by 10, 20 and 50 %. In the latter case, a winding of 1 diameter defines an excellent flexibility.

Experiment No. 3: Adhesion (IEC standard, Article 8-2) This experiment consists of rapidly stretching the wire to break. No cracks may occur.

Experiment no. U: Adhesion during twisting (VSM standard 23715, November 1956) This experiment is carried out in accordance with VSM standard 23713, November 1956. It consists of a lacquered wire with a length of 1 meter twisting around itself after being scraped along and generatris. The number of revolutions is required for a release of the paint. Experiment No. 5: Abrasion resistance There are two methods which give results which are not mutually comparable. '1) Reciprocating method (IEC standard 251-1, article 11) 10- 20 25. 30 550 ÄO ._.___._._. Í _-_____.__._ .., 7806149-6 12 Abrasion resistance is defined by the number of reciprocating cycles performed by a small, polished steel cylinder with a diameter of 0.1 mm, which is pressed against the lacquered wire with a load which is a function of the diameter of the trees, before the lacquer layer is worn. _ _ 7 2) The unidirectional method (NEMA NW 1000 standard, part 5, section 3-2 and 22-H-2) The abrasion resistance is given by the load in grams required to wear the varnish when scraping with a steel needle with 0.25 mm diameter, pressed against the wire with a load that increases during its movement. The Mcdel value is determined by 6 samples with 2 test pieces, each of which is scraped along 3 generatrices, separated by 12o °. ; Experiment No. 6: Resistance to solvents (IEC standard 251-1, article 12) The pen hardness of the paint is measured after immersion by 50 mm in a mixture of 30% refrigerant, 10% butanol and 60% white spirit at 60 ° C. Experiment No. 7: Thermoplastic test (IEC standard 251-1, Article 10) 7 Two wires are placed crossed on a heating block, which is heated to a given temperature, set to an accuracy of 1 2 ° C§ After 1 minute heating a load is imposed on the intersection of the wires. The softening point for the paint is greater than or equal to the block temperature if the insulation is not damaged within 2 minutes. Short circuit is detected by a voltage of 100 volts which is permanently applied between the two wires. the speed of the block is varied until the strength under load Tempera- is less than 2 minutes.

Experiment no. 8: Heat shock g Winding of lacquered wire, made on mandrels with a growing diameter from 1 to 6 times the nominal diameter of the trees, is heated for half an hour or 1 hour to a temperature selected The wire may in some cases have below- The smallest diameter noted, on in accordance with the type of varnish. thrown a previous stretch. which does not appear cracks after examination by means of an 8 times magnifying magnifying glass.

Experiment No. 9: Dielectric strength (IEC standard 251-1, article 'kei 13)' The measurement is carried out on windings, manufactured in accordance with the IEC standard. The values given are obtained as an average of 5 experiments. For diameters 0.315 and 0.800 mm, the winding is 125 mm and comprises 25 turns, performed below 1.70 N, and 8 turns below 13.50 N. 7 Experiment no. 10: Tangent for the loss angle (IEC standard 251 ~ 1, Article 19) ' prisoner delta. measured: by means of the one described in the IEC standard. the method at the frequency l kHz on a lacquered wire in a U-shape in a container containing mercury. Some measurements are performed at 50 Hz. _ The results for the paints are shown in the following table. 14 7806149-6 vom wow mn mm mm mm mn mq oom fl .oom fi om oz nom: Qom: wow wow Xm KN NH wa mw mw owno ow.o¶ mzw fl mdw fl xcm fi p xaw fl ß zcd fi p xsq fi p aa Mm mm w m Nn oom fl om nom: vom MN XH mm oæ.o ände øøw vom wow now wow _ mm mn mi _ mn mq mm mn mm mm mm mm m = | mm_ m: m: M ma .m = ¶ oom fl oom fl oon fi 7 ooma oom fi om om om oz om kom: »omm pom: _ fi owr nom: now wow now wow wow x fi xm xw xw xm wa x fl x fl x fl NH mm mm mm mm mw Qæ.o ow fl o Qw. @ ow fl o ow.o mzw fi nøw fi nsmnmswa csnnmsw fl ss Gsnnwdw fi xcm fi n xcw fl n xcm fi n w xm> xm w xm m xm = xm vom mm mn m: | mm oom fl oz Qmoq. nom Xm xm mm ow.o: ann w fi cnox w fl cnox xcman m Km wow mm än Inlïm oom fi oz Qcc: wow Mm, XN ww oæ fl o ANN cowhmv cmumë lhod fl w flfi ho fl zoc IOE uoñ m fl mum fl mw fl mw fi mw fl mw fi mw fl mw fl nw. vmß fi hm fl uccmm .m nu xmwhmm nummxwsmww mxw fl smx mn omw fl m: nnwum: oo uwscnmsccmm Umßx fi n fl wxcw wucwmw only m nn xmmmmw uwm fl cuæz nom: wow XN XN KN mm En N x nn.

AWC al cocmv 1 than xmwhmm al oo ßvuø f n ußnmümv -H QS xmwämu "w:« = «@ fi NVH> ws f n f SSP R if wn al CWSS» & OH w have xwmhnm .ßwßw fifl wwm r | J1L | ll¶l nwømzwcwmm mxm al cmxmä H QS Mmmäßm xw al xoo al pxumq hmuwëd al ññwä fi wnww mnwvmnß mwcwwwas mswømna fi mnmxwcwmm mxm flfl ßx fi wæm 7806149-6 15 ooom fl> oomM NN ooowm> oomH NN uoozm> oomH Nm 0000 »Qoøß fi uomß fi ooow fi oooß fi oooß fl> omw fi NO> N: M: hc xwm fi mh Anm oo fi U fi> b fl o> av cHmx: fl> uw: Hhom hmm mammans ^e§.o@H \ H \ H @ fi>> v umnpwmw flfl wn xw fi ppxm fl w fl m m nu xmw fi nw nmnmx x o mm> w nu xmwnßm umsnmn flfl ma xm fi umm fi aoënwa> ocnH bomm fl> oonH Nm KN ooø fl n ooø fl n uoo fl n N hc Mmmhmh hwmmxmcwwm mxw fi enma i vsoewa-e 16 _15: -20 25 _os rake with lacquer with excellent.

The high solubility of these resins enables their solubilization without the use of amines in ester type and / or glycol ether type non-polluting solvents. This type of composition has the advantage that excessive pollution of the air is avoided when releasing the evaporated solvents E into the atmosphere. Examples of other solvents which may be mentioned are methyl benzoate, methyl adipate, 2-nitropropane, propylene and ethyl carbonate, DMF, NMP, etc. A non-limiting example of a dilution is the following: 250 parts of resin according to Example 113 113 parts of methyl benzoate * : l_parts xylene H00 shares a lacquer with 50% active material and a viscosity according to ßaumé of 1100 mPas at 2o ° c.

This varnish is of interest in two respects, namely that the pollution is very limited, since the indicated solvents are designated as non-polluting, and that the varnish is very concentrated and as such can be used for varnishing, which is of economic importance.

Although the methods of preparation described above constitute preferred embodiments, it will be appreciated that various modifications may be made without departing from the scope of the invention, whereby certain methods, reagents, solvents or additives may be exchanged for others which give the same technical results. In particular, itaconic acid can be exchanged for one of its esters. * The resins defined above are particularly suitable for the production of insulating varnishes for wires, but they can also be used for the production of insulating films, foils and casting compounds, especially for use in electrical engineering.

Claims (1)

1.,? 7806149-6 lliäêllšïííäf Lacquer, containing a polyester or polystyrene resin, prepared by polyesterification of at least one polycurbonic acid containing at least one five-membered, cyclic lactam, or of a compound capable of producing such an acid, having at least one polyalcoholic acid, wherein is prepared by the condensation of itaconic acid or one of its substituted derivatives or its esters with a primary amine, which further contains an additional amino group or a carboxyl group at the end of the chain, and characterized in that it contains as solvent an organic solvent which is low or not at all polluting, and which consists of either a mixture of water and an organic, cooperating solvent, which at least in part consists of dimethylaminoethanol, and optionally further dimethylformamide and / or methylglycol and / or N -methyl-pyrrolidone, or is an anhydrous solvent from the group comprising at least one alkyl ester and a glycol ester or glycol ether.