DE891125C - Process for the production of storage-stable lacquers and paints pigmented with basic pigments or metal powders - Google Patents

Description

Process for the production of storage-stable, with basic pigments or metal powders of pigmented varnishes and paints The manufacture of with basic pigments or paints and varnishes pigmented with metal powders has so far been very frequent due to the thickening that occurs after a shorter or longer period of time or discoloration encountered particular difficulties. Since these appearances by the presence of acidic groups in the binders of these lacquers is conditional, In the beginning, efforts were made to produce acid-free paints in order to avoid the disturbances, which can be attributed to the formation of metal salts, to avoid these efforts did not bring ultimate success. In the case of bronze paints, it later proved to be advantageous proven to add small amounts of acids to the finished bronze paint, such as B. boric acid, citric acid, Tartaric acid, lactic acid, malic acid, etc.; to add, whereby a certain amount, but absolutely unsatisfactory improvement in durability can be achieved could.

In contrast, it has now been found that by adding stabilized Aluminum alcoholate solutions produced by known processes and the paints before pigmentation, expediently with moderate warming, thickenings are added in the case of pigmentation, finite basic pigments or color changes in bronze paints should be avoided during subsequent storage.

This is where the acid number of the binder contained in the paints comes in particular importance with regard to the changes occurring during storage to. It also forms when the aluminum alcoholate solution or the alcoholate preparation is added the calculation standard for the to be added Amount of alcohol, order To avoid a color change permanently, the alcoholate solution must at least as such contain a lot of aluminum that the acidic groups of the binder are saturated. As with many and especially with drying binders during storage and If acidic groups are still formed when drying, it is advisable to use the alcoholate preparation to be based on the aluminum number of the binder (see E. Eigenherger, Fette and Seifen, 1944, Book II, p. 45). E. Eigenberger differentiates the upper aluminum number (without AI number = g aluminum, which are bound by 100 g substance) and the lower Aluminum number (and Al number = upper aluminum number minus that of the acid number equivalent Aluminum value, where the conversion factor for the acid number in units of the aluminum number Is 0.053).

If you want to block the acidic groups in paints with aluminum alcoholate, the aluminum number equivalent corresponding to the acid number is determined and found in this size a measure of the minimum aluminum content of the stabilized to be added Aluminum alcoholate solution. Depending on the type of pigments used and due to the particularly with drying binders during storage and acidic groups occurring in the film, the aluminum dose is selected. While in the case of metal bronze paints, it is expediently higher than the aluminum number equivalent the acid number expresses it, it can be the case with lacquers mixed with basic pigments are also lower, since a reduction in the acid number is sufficient here. the The upper limit of the aluminum dose gives the upper aluminum number, which indicates how much Grams of aluminum can be bound by 100 g of the binder. The finished Bronze paint, for example, is therefore stabilized a lot at ordinary temperature Aluminum alcoholate solution added, its aluminum content between the aluminum number equivalent the acid number and the upper aluminum number. In this way you get paints, whose acidic groups are blocked and none of them, even after prolonged storage Changes occur.

It is known to use aluminum alcoholates in oil-containing paints and adding varnishes to improve gelation and film formation thereof. This way of working, which leads to a lower shelf life of the treated paints leads is fundamentally different from the method according to the invention. In which the latter are pigmented paints in their using basic pigments Shelf life and bronze paints also improved in their color fastness, what was not to be expected after the acquaintance, but the painting technique a desirable one Improvement of these Aristrichstoffe has brought.

Example i The solution of 700 g of a rosin resin ester with an acid number 8.7, o. AI number 2.25 and u. AI number i, 79 in toluene is stabilized with 224 ccm Aluminum butoxide solution is added, the aluminum content of which is 56 mg per cubic centimeter amounts to. After adding 25 @ °% copper bronze, based on the body content of the solution, a bronze lacquer is obtained which is not subject to greening on storage is. The same paint without aluminum alcoholate shows strong results after a few days Green color of the supernatant solution.

Example e The solution of 700 g of the modified phenolic resin known under the trade name Albertol III L and having an acid number 16.5, an Al number 4.2 and an Al number 3.3 in 300 g of toluene is stabilized with 174 cc of aluminum butoxide solution added, which contains 60.0 mg of aluminum in 1 cc of solution. After stirring in 25% copper bronze, based on the resin content of the solution, a bronze lacquer is obtained which shows no discoloration on storage. The same approach without aluminum alcoholate preparation begins to turn green after 2 days.

Example 3 160 g of a maleate resin with the acid number 51.8, the o. AI number 5.6 and the u. AI number. 2; 9 are dissolved with 40 g of thinner made from mineral spirits and butanol in a ratio of 2: 1, and 57.8 ccm of a stabilized aluminum butoxide solution, which contains 53 mg of aluminum per cubic centimeter, is added. The prepared resin solution is kept at 50 to 60 ° for 30 minutes and then adjusted to q = 60 seconds (20 °) by further dilution. 140 g of this are pigmented with 72 g of zinc oxide, ie in the ratio resin: pigment = i: i.

The viscosity values are ii (pigm.): = io2.6 sec. (2o °) after 48 h - = 126.6 seconds (2o °) after 96 h 17 - = 13o, 8 sec. (2o °). A sample of the same resin with the above thinner adjusted to 77 = 60 seconds, 135 g of which pigmented with 79 g of zinc oxide in the ratio resin: pigment = i: i gives 77 (Pigm.) = 1i4 sec. (2o °) after. 48 h - = 477 seconds (2o °) after 96 h - = 896 seconds (2o °). The zinc white compatibility was tested as follows: The paint resin to be tested for zinc white compatibility is adjusted to approximately q = 60 seconds (20 °) by diluting with solvent. After pigmentation in the ratio resin: zinc oxide = i: i, the flow time in the Din beaker (»pigm.) Is determined again and the determination is repeated after 48 or 72 hours. The increase in the outflow time should not be more than 25%. The aluminum-prepared lacquer solutions are expediently heated to 50 to 60 ° for 30 minutes before pigmentation.

Example 4 100 g of a modified phenolic resin with the trade name Albertol III L are fused with zoo g rosin at 80 °. This gives the melt an acid number of 46; 1, o. AI number 5.8 and u, AI number 3.4. 21o g of this resin combination are dissolved in 100 g of thinner made from mineral spirits and butanol in a ratio of 2: 1, and 79.2 cc of stabilized aluminum butoxide solution, which contains 53 mg of A1 per cubic centimeter, is added. The aluminized resin solution is heated to 50 to 60 ° for 30 minutes and then adjusted to q = 60 seconds (20 °) by adding more thinner. Of these, zoo g are pigmented with 100.8 g zinc oxide in the ratio resin: pigment = i: i.

The viscosity values are 27 (Pigm.) = 97 sec. (2o °) after 48 h - = 1i8.2 sec. (2o °) after 72 h - = 125.2 seconds (20 °). A sample of the same resin with the above thinner adjusted to 21 = 60 sec 27 (pigm.) = 134.6 sec. (2o °) after 48 h - = 224.0 seconds (2o °) after 72 h - = 233.0 seconds (2o °). EXAMPLE 5 140 g of an oil-modified alkyd resin which is incompatible with zinc white and has an acid number 9.5, an AI number 4.3 and an AI number 3.8 are dissolved in 60 g of thinner made from mineral spirits and butanol in a ratio of 2: 1 and with 52, 8 cc of a stabilized aluminum butoxide solution containing 53 mg of Al per cubic centimeter is added. The pigmented resin solution is kept at 50 to 60 ° for 30 minutes and then adjusted to 77 = 60 seconds (20 °) by further dilution. 140 g of this are pigmented with 62.5 g of zinc oxide in a resin: pigment = i: x ratio.

The viscosity values are 71 (pigm.) = 8o, 2 sec. (2o °) after 48 h - = 86.6 seconds (2o °) after 96 h - = 93.4 seconds: (2o °). A sample of the same resin with the above thinner adjusted to ii = 60 seconds, 125 g of which pigmented with 70 g of zinc oxide in the same ratio of resin: pigment gives (pigm.) = iig, 2 sec. (2o °) after 48 h - = 165.4 seconds (2o °) after 96 h - = ig2, o sec. (2o °).

Claims (1)

PATENT CLAIM: A process for the production of storage-stable, using basic pigments or metal powders, pigmented lacquers and paints, characterized in that the binders on which they are based are treated with an aluminum alcoholate solution stabilized in a known manner before pigmentation, expediently in solution and with moderate heating will. Cited publications: Chemisches Zentralblatt, 195o, Bd.11, p.113, para. 7; Journal "Fette und Seifen", 1944, Vol. 51, pp. 45 and 87 (work by E. Eigenberger); Zeitschrift für Angewandte Chemie, 1940, 53rd year, p. 266 (summary work by Bersin); German patent specification No. 653 249.