FI58790C - VAT ALKALISKT RENGOERINGSMEDEL SAERSKILT FOER YTOR AV ALUMINIUM ELLER ALUMINIUMLEGERINGAR - Google Patents

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jSgr · (11) UTLÄGGNINGSSKIUFT bö / 9U

C ^ 45j Patent granted 10 04 1931 Patent iseddelat V (51) Kv.lk?/lm.CI.3 C 11 D 7/06 ENGLISH — Fl N LAN D (21) ρ «* ^ ιΐΜ * · ^ -ρκ · πβΜβΐΜΜηβ 2603/7 ** (22) HakamitpUvi - AMiMuilnpdai 05.09-7 * + (23) AlkuplM — GUtljhaoda * 05.09-7 * + (41) Tullut JulklMkal - Bllvit offantllg 08.03.75

Patent · la rakiaterihallitu * .... ......, _ '(44) Date of publication and publication. -

Patent · och ngleUntyrmlemt '' Anaökan utlagd och Utl.skrlftan pubUcend 31.12.80 (32) (33) (31) fyy ^ Atty etuoikaua — Baglrd prlorltet 07-09-73

Sweden-Sweden (SE) 7312217-8 Proven-Styrkt (71) AB Helios Kemisk-Tekniska Fabriker, S-126 11 Stockholm 32,

Sweden-Sweden (SE) (72) Barbro Sylvia Irene Liiborg, Södertälje, Sweden-Sweden (SE) (7 * +) Oy Kolster Ab (5 * +) Aqueous alkaline cleaner, especially for aluminum or aluminum alloy surfaces - Vattenhaltigt alkaliskt ren -göringsmedel, särskilt för ytor av Aluminum eller aluminiumlege-ringar «

The invention relates to an aqueous alkaline cleaner, in particular for aluminum or aluminum alloy surfaces, having a pH of 12 to 1 and containing one or more potassium and / or sodium hydroxides and a corrosion inhibitor, which detergent is characterized in that it contains one or more corrosion inhibitors. a number of unsaturated fatty acids such as oleic acid, linoleic acid, tall oil acid or castor oil acid, an alkali metal salt, and optionally a lime soap dispersant having an alkali metal hydroxide content of at least 0.1% by weight and a corrosion inhibitor content of at least 0.02% by weight.

It is known that most medium-strength and all highly temporal chemicals except ammonia have a detrimental, more or less detrimental effect on aluminum and most light metal alloys, however, weakly temporal cleaning agents only to a negligible extent. Combinations of surfactants, complexing agents and silicates, in particular metasilicate, have hitherto been used as cleaning agents in industrial grill ovens, 2,58790, which are usually constructed of aluminum sheet metal and aluminum components. However, at the required high silicate content, precipitates are obtained which make the grills mottled by the action of silicate coatings on aluminum surfaces. With low or no metasilicate concentrations, the cleaning efficiency remains poor.

The present invention completely eliminates the above-mentioned drawbacks. In working to find suitable inhibitors, to reduce the detrimental effects of commonly used alkaline cleaners on aluminum surfaces, it has surprisingly been found that the already relatively small addition of alkali salts of unsaturated fatty acids is very effective in preventing the harmful effects of aqueous potassium or sodium hydroxide solutions. Very satisfactory results are given here by oleic acid, linoleic acid, tall oil acid and castor oleic acid, to name a few of the most common unsaturated fatty acids. By way of comparison, the salts of saturated fatty acids such as palmitic acid,? -Sulfopalmitic acid, tallow fatty acid, eurucic acid, lauric acid and coconut fatty acid did not act as an inhibitor. Table 1 shows a representative range of tested cleaning combinations that show the relationship between the alkali and inhibitor of the active ingredients. The table also clearly shows the detrimental effects of the presence of sodium tripolyphosphate (STPP), nitrile acetic acid (NTA), ethylenediaminetetraacetate (EDTA) and metasilicate (Meta). These substances should therefore be avoided as additives.

58790 3

table 1

Type of inhibitor Aluminum corrosion

Alkali pH Esto- (alkali salt time 15 min. Temperature 70+ 5 ° C

% acid corresponding to substances) 0.1 KOH 12.0 - - Strong effect 0.25 "12.3 - - 0.5" 12.6 - - Very strong effect.

0.5 "" 0.25 Tall oil Acid No effect 0.5 "" 0.125 0.5 "" 0.075 0.5 "" 0.025 Predisposition to adverse effects 0.5 "" 0.5 Palmitic acid Strong effect 0.5 "" 0, 25 0.5 "" 0.1 0.5 "" 0.5 oC-sulfopalmitin- Very strong effect on acid

Di 0.5 "" 0.25 Effect 0.5 "" 0.1 0.5 "" 0.05 0.5 "" 0.5 C (.- sulfopalmitin- Strong effect on acid

Mono 0.5 "" 0.25 0.5 "" 0.1 0.5 "" 0.05 0.5 "" 0.25 Tallow fatty acid Very strong effect 0.5 "" 0.25 1.2 dicarboxylic acid 0 .5 "" 0.5 Lauric acid Strong effect 0.5 "" 0.1 Effect 0.5 "" 0.05 0.5 "" 0.5 Coconut fatty acid Strong effect 0.5 "" 0.25 k 58790 (Table 1 continued)

Alkali pH Preventant Type of inhibitor Aluminum corrosion% of substance (alkali salt time 15 min, temp.

% corresponding acid) 70 + ^ 5 C

0.5 KOH 12.6 0.1 Coconut fatty acid Strong effect 0.5 "" 0.05 0.5 "" 0.5 Eurucic acid Very strong effect 0.5 "" 0.25 0.5 "" 0.1 0 .5 "" 0.05 0.5 "" 0.25 Oil appo No effect 0.5 "" 0.1 0.5 "" 0.05 0.5 "" 0.25 Linoleic acid 0.5 "" 0 .1 0.5 "" 0.05 0.5 "" 0.25 Castor oil acid 0.5 "" 0.1 0.5 "" 0.05 0.5 NaOH "0.05 Tall oil acid 0.5" "0.025 Predisposition to adverse effects 0.25 NaOH) "0.05 No effect 0.25 KOH and 0.25 NaOH) 12.3 0.05 0.25 MEA / 0.25 NaOH) 12.3 0.05

0.25 NH 4 OHJ

0.25 KOH 1 12.3 0.05

0.25 NH 4 OHJ

0.25 KOH> 12.1+ 0.05 0.25 Na 2 CO 2 0.25 KOH) 12.6 0.05 Effect 0.25 Meta $ 0.25 KOH 7 12.2 0.05 Strong effect 0.25 STPP) 0.25 KOH "0.25 0.25 STPP) 0.25 KOH *)" 0.7 0.25 STPPj 0.25 KOH ")" 1, 1 + 0.25 STPP) "(t Table 1 continued) 5 58790

Alkali pH Preventant Type of inhibitor Aluminum corrosion% of substance (alkali salt for 15 min. Temp.

% acid) 70+ 5 ° C

0.25 K0h) "1.1+ Tall oil Acid Strong effect 0.1 STPP) 0.25 KOH) 12.6 0.05 0.25 NTAj 0.25 KOH ^" 0.25 0.25 WTAj 0.25 KOH *) "0.05

0.25 EDTAJ

0.25 KOH Ί "0.25

0.25 EDTAJ

0.25 KOH "0.7 -" -

0.25 MetaJ

1.5 NaOH *) 13.5 0.075 No effect

0.1U KOH J

0.7 KOH 13.0 0.35 1.1+ KOH 13.5 0.7

If the cleaning agent according to the invention is to be used diluted with hard water, it is advantageous to add tallow fatty alcohol containing 11 moles of ethylene oxide, whereby the ethylene oxide product already acts as a dispersant of lime soap in a small amount and acts on the foam, which is considerably reduced.

The cleaning agent according to the invention is preferably used at temperatures above room temperature, e.g. at about 70 ° C, when cleaning grill ovens. Even at boiling temperature, the cleaning agent according to the invention can be used without dissolving the aluminum, even if the pH is between 12 and 13.