Compositions – Heat-exchange – low-freezing or pour point – or high boiling... – Organic components
Reexamination Certificate
2003-10-02
2004-11-16
Ogden, Necholus (Department: 1751)
Compositions
Heat-exchange, low-freezing or pour point, or high boiling...
Organic components
C252S075000, C252S077000, C252S078100, C252S078300, C008S543000, C008S650000, C008S675000
Reexamination Certificate
active
06818147
ABSTRACT:
The present invention relates to novel antifreeze concentrates based on alkylene glycols or derivatives thereof or on glycerol, comprising, as dye, Colour Index (“C.I.”) Reactive Violet 5 (Colour Index No. 18097). The present invention furthermore relates to ready-to-use aqueous coolant compositions which comprise said antifreeze concentrates. The present invention also relates to the use of these antifreeze concentrates for the preparation of aqueous coolant compositions for internal-combustion engines.
Antifreeze concentrates for the cooling systems of internal-combustion engines, for example in automobiles, usually comprise alkylene glycols, especially ethylene glycol or propylene glycol, as the principal component. For use in the cooling system, they are diluted with water and are intended to ensure good heat dissipation as well as provide protection against freezing.
Alkylene glycol/water mixtures are very corrosive at the operating temperatures of internal-combustion engines. For this reason, the various metals, such as steel, cast iron, copper, brass, aluminum, magnesium and alloys thereof, as well as solder metals, for example solder tin, which are used in the cooling system have to be adequately protected against a very wide variety of types of corrosion, for example pitting corrosion, crevice corrosion, erosion or cavitation, through the use of corrosion inhibitors.
Antifreeze concentrates and radiator protection compositions are almost always colored by addition of a dye in order to prevent confusion with other functional fluids in motor vehicles, for example screen wash or brake fluids. The coloring is also intended to be recognizable during and after use in the cooling system.
Radiator protection compositions are subjected to extreme temperatures and strongly oxidizing conditions in practice. Only very few dyes have been found which are stable in an environment of this type. Commercial use is made principally of C.I. Direct Blue 199 (C.I. 74190), C.I. Direct Blue 86 (C.I. 74180), C.I. Acid Green 25 (C.I. 61570), C.I. Acid Yellow 73 (C.I. 45350) and uranine (sodium fluoroscein). C.I. Acid Green 25 is generally combined with C.I. Acid Yellow 73 or with uranine, giving a fluorescent green color. C.I. Acid Yellow 221 is frequently also used as yellow dye and C.I. Basic Violet 10 (C.I. 45170) as red dye.
U.S. Pat. No. 5,723,060 (1) describes blue dyes having a 1-amino-4-anilinoanthraquinone structure as colorant for coolant compositions.
U.S. Pat. No. 5,725,794 (2) recommends coolant compositions which comprise polyoxyalkylene-substituted reactive dyes which are said to have improved thermal stability due to the polymer substituents; for example, reactive dyes, such as C.I. Basic Violet 3 or C.I. Reactive Violet 5, are chemically reacted specifically with polyoxyalkyleneamines or with polyoxyethylene-dimethylsiloxane copolymers. EP-B 864 616 (3) likewise teaches a reaction of reactive dyes of this type with polyoxyethylene-dimethylsiloxane copolymers and the use thereof in coolant compositions. Disadvantages in the teaching of (2) and (3) compared with the unsubstituted reactive dyes are, in particular, the additional synthesis step and the lack of commercial availability of such dyes.
From the viewpoint of the automobile industry, a disadvantage of many of the dyes employed in radiator protection compositions is that, due to the slight intentional leakage desired for lubrication of the water pump, they form colored residues of the escaped coolant on the outer metal surface of the water pump, the occurrence of which may give the impression of rust formation or incorrectly be attributed to defective or perished pump gaskets, resulting in unjustified customer complaints.
There is thus a demand for thermally stable dyes which do not form colored residues, but instead at most colorless residues after drying on metal surfaces at leaking points of the cooling system.
Surprisingly, it has now been found that the unsubstituted reactive dye C.I. Reactive Violet 5 (Colour Index No. 18097) not only has excellent thermal stability in coolants, but also, in contrast to other dyes employed in coolants, does not leave colored residues on metal surfaces at leaks in the cooling system.
The present invention thus relates to antifreeze concentrates based on alkylene glycols or derivatives thereof or on glycerol, comprising from 0.0005 to 0.1% by weight, preferably from 0.001 to 0.05% by weight, in particular from 0.002 to 0.02% by weight, of the dye C.I. Reactive Violet 5 (Colour Index No. 18097), based on the total amount of the concentrate.
C.I. Reactive Violet 5 (Colour Index No. 18097) is the copper complex of 5-(acetylamino-)-4-hydroxy-3-[[2-hydroxy-4-[[2-(sulfoxy)ethyl]sulfonyl]phenyl]azo]-2,7-naphthalenedisulfon ic acid. Its CAS registry number is 12226-38-9.
The dye C.I. Reactive Violet 5 is incorporated into the antifreeze concentrate in underivatized form, i.e. in commercially available form. The incorporation is carried out in such a way as to exclude chemical reactions with constituents of the antifreeze concentrate—at least before introduction into the cooling system.
The present invention therefore also relates to a process for the preparation of antifreeze concentrates wherein the dye C.I. Reactive Violet 5 (Colour Index No. 18097) is incorporated into antifreeze concentrates based on alkylene glycols or derivatives thereof or on glycerol in an amount of from 0.0005 to 0.1% by weight, preferably from 0.001 to 0.05% by weight, in particular from 0.002 to 0.02% by weight, based on the total amount of the concentrate. The incorporation is usually carried out before preparation of the ready-to-use aqueous coolant compositions from the concentrates or before introduction of the ready-to-use aqueous coolant compositions into the cooling system.
In a preferred embodiment, the antifreeze concentrates according to the invention comprise the following compounds in addition to the dye:
a) from 0.05 to 5% by weight, based on the total amount of the concentrate, of one or more aliphatic, cycloaliphatic or aromatic monocarboxylic acids, each having from 3 to 16 carbon atoms, in the form of their alkali metal, ammonium or substituted ammonium salts, and/or
b) from 0.05 to 5% by weight, based on the total amount of the concentrate, of one or more aliphatic or aromatic di- or tricarboxylic acids, each having from 3 to 21 carbon atoms, in the form of their alkali metal, ammonium or substituted ammonium salts, and/or
c) one or more alkali metal borates, alkali metal phosphates, alkali metal silicates, alkali metal nitrites, alkali or alkaline earth metal nitrates, alkali metal molybdates or alkali or alkaline earth metal fluorides, each in amounts of up to 1% by weight, based on the total amount of the concentrate, and/or
d) from 0.05 to 5% by weight, based on the total amount of the concentrate, of one or more aliphatic, cycloaliphatic or aromatic amines having from 2 to 15 carbon atoms, which may additionally contain ether oxygen atoms or hydroxyl groups, and/or
e) from 0.05 to 5% by weight, based on the total amount of the concentration, of one or more monocyclic or bicyclic unsaturated or partially unsaturated heterocyclic compounds having from 4 to 10 carbon atoms, which may be benzo-fused and/or may carry additional functional groups, and/or
f) from 0.05 to 5% by weight, based on the total amount of the concentrate, of one or more tetra(C
1
-C
8
-alkoxy)silanes (tetra-C
1
-C
8
-alkyl orthosilicates), and/or
g) from 0.05 to 10% by weight, based on the total amount of the concentrate, of one or more carboxamides and/or sulfonamides, and/or
h) up to 1% by weight, based on the total amount of the concentrate, of one or more hard-water stabilizers based on polyacrylic acid, polymaleic acid, acrylic acid-maleic acid copolymers, polyvinylpyrrolidone, polyvinylimidazole, vinylpyrrolidone-vinylimidazole copolymers and/or copolymers of unsaturated carboxylic acids and olefins.
The compounds from groups a) to g) are generally corrosion inhibitors.
Suitable
Dambach Stefan
Meszaros Ladislaus
Nitzschke Uwe
Wenderoth Bernd
BASF - Aktiengesellschaft
Ogden Necholus
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