CA2147046C - Polymer-thickened de-icing and anti-icing composition for aircraft - Google Patents
Polymer-thickened de-icing and anti-icing composition for aircraft Download PDFInfo
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- CA2147046C CA2147046C CA002147046A CA2147046A CA2147046C CA 2147046 C CA2147046 C CA 2147046C CA 002147046 A CA002147046 A CA 002147046A CA 2147046 A CA2147046 A CA 2147046A CA 2147046 C CA2147046 C CA 2147046C
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/18—Materials not provided for elsewhere for application to surfaces to minimize adherence of ice, mist or water thereto; Thawing or antifreeze materials for application to surfaces
- C09K3/185—Thawing materials
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/18—Materials not provided for elsewhere for application to surfaces to minimize adherence of ice, mist or water thereto; Thawing or antifreeze materials for application to surfaces
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Abstract
The de-icing and anti-icing composition described, which is based on glycols and water, contains as thickener water-soluble crosslinked copolymers of acrylic acid or methacrylic acid as principal monomer and an ester or amide of acrylic acid or methacrylic acid having a long alkyl radical in the ester group and one or two long alkyl radicals in the amide group as secondary monomer.
These copolymers are used to produce type II de-icing and anti-icing compositions for aircraft, which have a long holdover time and at the same time, owing to the pronounced pseudoplasticity of the copolymer, outstanding flow-off characteristics.
These copolymers are used to produce type II de-icing and anti-icing compositions for aircraft, which have a long holdover time and at the same time, owing to the pronounced pseudoplasticity of the copolymer, outstanding flow-off characteristics.
Description
~14704f HOECHST AKTIENGESELLSCHAFT HOE 94/F 911 Dr.GL-nu Werk Gendorf Polymer-thickened de-icing and anti-icing composition for aircraf t Description The invention relates to a de-icing and anti-icing composition for aircraft which is based on glycols and water and contains water-soluble crosslinked acrylic polymers as thickener.
De-icing and anti-icing compositions for aircraft (referred to below for the sake of brevity simply as de-icing compositions or de-icing liquids) are employed to remove ice, snow and/or hoarfrost from certain surfaces of aircraft and to avoid such deposits on these areas.
The period of time over which the de-icing liquid pro-vides protection against the re-formation of ice, snow and/or hoarfrost on the aircraft is termed the re-icing protection time or holdover time. The "Recommendations for De-/Anti-Icing of Aircraft on the Ground" (March 1993 edition) of the Association of European Airlines (AEA) and the International Standardisation Organisation (ISO) specifications 11075, 11076 and 11078 specify two types of aircraft de-icing liquids. Type I liquids are composed essentially of glycol, water and corrosion inhibitors with or without surfactants and pH regulators, while type II liquids additionally contain a water-soluble polymer as thickener in order to bring about a highly viscous, pseudoplastic consistency.
Particular expectations of aircraft de-icing compositions of said type II are that they should provide as long as possible a term of protection against re-icing of the wings prior to takeoff under extreme weather conditions such as snowfall or freezing rain and good flow-off from 214'~04~
De-icing and anti-icing compositions for aircraft (referred to below for the sake of brevity simply as de-icing compositions or de-icing liquids) are employed to remove ice, snow and/or hoarfrost from certain surfaces of aircraft and to avoid such deposits on these areas.
The period of time over which the de-icing liquid pro-vides protection against the re-formation of ice, snow and/or hoarfrost on the aircraft is termed the re-icing protection time or holdover time. The "Recommendations for De-/Anti-Icing of Aircraft on the Ground" (March 1993 edition) of the Association of European Airlines (AEA) and the International Standardisation Organisation (ISO) specifications 11075, 11076 and 11078 specify two types of aircraft de-icing liquids. Type I liquids are composed essentially of glycol, water and corrosion inhibitors with or without surfactants and pH regulators, while type II liquids additionally contain a water-soluble polymer as thickener in order to bring about a highly viscous, pseudoplastic consistency.
Particular expectations of aircraft de-icing compositions of said type II are that they should provide as long as possible a term of protection against re-icing of the wings prior to takeoff under extreme weather conditions such as snowfall or freezing rain and good flow-off from 214'~04~
the trailing edge of the wings when the aircraft takes off. Thus the ISO standard 11078, which came into force is 1993, requires a re-icing protection time of at least 30 minutes at -5°C in the "Water Spray Endurance Test"
(the de-icing liquid is subjected beforehand for 5 minutes to a shear stress of 3,500 revolutions per minute). With respect to flow-off characteristics, ISO 11078 describes for the first time a laboratory test, the "Aerodynamic Acceptance Test", which prescribes a maximum thickness (Boundary Layer Displacement Thickness, d*) of the film of de-icing composition which remains after a simulated takeoff of not more than 10 mm at -30°C
and not more than 9.5 mm at -10°C.
The holdover time and the flow-off characteristics of a type II de-icing composition are critically affected by the thickener. The discovery of a good polymer thickener is made more difficult by the fact, inter alia, that the two properties of holdover time and flow-off charac-teristics are essentially in conflict with one another.
Polymer-thickened aircraft de-icing compositions are described, for example, in DE-A-24 23 893 (Derwent Abstract AN 83335W) and also in EP-H-0 050 700 (US-A-4 358 389), EP-B-0 231 869 (US-A-4 744 913) and EP-B-0 360 183. They essentially comprise a) from 35 to 70% by weight of at least one glycol from the group consisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5% by weight of at least one water-soluble polymer as thickener, c) from 0.02 to 1.5% by weight of at least one surfactant from the group consisting of anionic and nonionic surfactants, d) at least one corrosion inhibitor in an effective quantity, e) at least one basic compound from the group consist-ing of alkali metal carbonates, alkali metal 214'~~ .46 hydroxides and amines, to establish a pH of from 7 to 11, and f) water as the remainder to 100% by weight, percentages by weight being based on the (ready-to-use) de-icing composition.
The de-icing and anti-icing composition for aircraft surfaces which is described in DE-A-24 23 893 contains as thickener water-soluble crosslinked or non-crosslinked homopolymers or copolymers of acrylic acid or methacrylic acid, in which the comonomer may be present in a quantity of from 5 to 70 mol% (based on the overall monomer mixture) . Comonomers mentioned are methyl, ethyl or butyl esters of acrylic, methacrylic or malefic acid, vinyl acetate, styrene, lower olefins and acrylamides or methacrylamides. In EP-B-0 360 183 the thickeners advoc-ated are water-soluble crosslinked polyacrylic acid products, while EP-B-0 050 700 additionally advocates water-soluble crosslinked copolymers of acrylic acid or methacrylic acid with a comonomer content of from 2 to 50% by weight (based on the copolymer); nothing more is said about the nature of the comonomer. In EP-B-0 231 869 a mixture essentially comprising a water-soluble cross-linked acrylic acid homopolymer and a copolymer of acrylic acid and acrylamide is employed as thickener. The known thickeners described give the aircraft de-icing compositions a certain pseudoplastic behavior, i.e. a relatively high viscosity (called viscosity at rest, flow limit or "yield value" ) which decreases when the composi-tion is subjected to shear stress. The intention is thereby to achieve a good holdover time coupled with adequate flow-off characteristics. However, the require-ments of the specification ISO 11078 are so high that the thickeners described either bring about only an adequate holdover time (as a result of high viscosity at rest) while failing to meet the requirements in respect of flow-off characteristics, or bring about flow-off charac-teristics (as a result of low viscosity at rest) but then do not meet the requirements with respect to holdover 214'~04~
(the de-icing liquid is subjected beforehand for 5 minutes to a shear stress of 3,500 revolutions per minute). With respect to flow-off characteristics, ISO 11078 describes for the first time a laboratory test, the "Aerodynamic Acceptance Test", which prescribes a maximum thickness (Boundary Layer Displacement Thickness, d*) of the film of de-icing composition which remains after a simulated takeoff of not more than 10 mm at -30°C
and not more than 9.5 mm at -10°C.
The holdover time and the flow-off characteristics of a type II de-icing composition are critically affected by the thickener. The discovery of a good polymer thickener is made more difficult by the fact, inter alia, that the two properties of holdover time and flow-off charac-teristics are essentially in conflict with one another.
Polymer-thickened aircraft de-icing compositions are described, for example, in DE-A-24 23 893 (Derwent Abstract AN 83335W) and also in EP-H-0 050 700 (US-A-4 358 389), EP-B-0 231 869 (US-A-4 744 913) and EP-B-0 360 183. They essentially comprise a) from 35 to 70% by weight of at least one glycol from the group consisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5% by weight of at least one water-soluble polymer as thickener, c) from 0.02 to 1.5% by weight of at least one surfactant from the group consisting of anionic and nonionic surfactants, d) at least one corrosion inhibitor in an effective quantity, e) at least one basic compound from the group consist-ing of alkali metal carbonates, alkali metal 214'~~ .46 hydroxides and amines, to establish a pH of from 7 to 11, and f) water as the remainder to 100% by weight, percentages by weight being based on the (ready-to-use) de-icing composition.
The de-icing and anti-icing composition for aircraft surfaces which is described in DE-A-24 23 893 contains as thickener water-soluble crosslinked or non-crosslinked homopolymers or copolymers of acrylic acid or methacrylic acid, in which the comonomer may be present in a quantity of from 5 to 70 mol% (based on the overall monomer mixture) . Comonomers mentioned are methyl, ethyl or butyl esters of acrylic, methacrylic or malefic acid, vinyl acetate, styrene, lower olefins and acrylamides or methacrylamides. In EP-B-0 360 183 the thickeners advoc-ated are water-soluble crosslinked polyacrylic acid products, while EP-B-0 050 700 additionally advocates water-soluble crosslinked copolymers of acrylic acid or methacrylic acid with a comonomer content of from 2 to 50% by weight (based on the copolymer); nothing more is said about the nature of the comonomer. In EP-B-0 231 869 a mixture essentially comprising a water-soluble cross-linked acrylic acid homopolymer and a copolymer of acrylic acid and acrylamide is employed as thickener. The known thickeners described give the aircraft de-icing compositions a certain pseudoplastic behavior, i.e. a relatively high viscosity (called viscosity at rest, flow limit or "yield value" ) which decreases when the composi-tion is subjected to shear stress. The intention is thereby to achieve a good holdover time coupled with adequate flow-off characteristics. However, the require-ments of the specification ISO 11078 are so high that the thickeners described either bring about only an adequate holdover time (as a result of high viscosity at rest) while failing to meet the requirements in respect of flow-off characteristics, or bring about flow-off charac-teristics (as a result of low viscosity at rest) but then do not meet the requirements with respect to holdover 214'~04~
time. The known polymer thickeners described are therefore unable to conform simultaneously to the water spray endurance time prescribed in ISO 11078 and the limitation of the boundary layer displacement thickness in the aerodynamic acceptance test, the latter limitation having been newly laid down also in ISO 11078.
Further prior art is represented by the relatively recent document WO 93/24543, which describes linear or cross-linked polycarboxylates, containing specific macro-monomers, as thickeners for type II aircraft de-icing liquids. The macromonomer contains a hydrophobic terminal radical from the group of the alkaryls and is connected to the polycarboxylate (polyacrylate, polymethacrylate and the like) via a bridging link (see for example pages 9 and 19). This polymer thickener therefore requires monomers of relatively complex composition and can only be prepared over a plurality of reaction stages.
As mentioned above, the two properties of holdover time and flow-off characteristics are in conflict with one another. In order to achieve adequate flow-off character-istics, the chosen viscosity - and therefore the chosen concentration of thickener - must be as low as possible.
On the other hand, a sufficient holdover time requires a maximum yield value of the de-icing composition and thus, in general, a high viscosity and high concentration of thickener.
The object of the invention, accordingly, is to provide thickener polymers which are of simple composition and can be prepared easily and which bring about, in the ready-to-use aircraft de-icing composition, an increased pseudoplasticity - in other words, a greater decrease in viscosity under increasing shear stress - and which thereby, when subjected to shear stress and despite their high viscosity at rest, become mobile markedly more quickly and thus flow off better. The novel de-icing composition of enhanced pseudoplasticity should pass the 29374-64(S) water spray endurance test owing to its adequate viscosity at rest and should at the same time, owing to faster flow-off in the wind tunnel or on takeoff, attain the low values required for the boundary layer displacement thickness in the aerodynamic acceptance test. The novel type II aircraft de-icing composition should therefore be based on a simple and readily accessible polymer thickener and should easily fulfill the requirements of ISO Standard 11078 with regard to holdover time and flow-off characteristics.
According to one aspect of the present invention, there is provided a de-icing and anti-icing composition for aircraft which is based on glycols and water and contains water-soluble crosslinked acrylic polymers as thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the 2o amide group in a minority amount.
According to another aspect of the present invention, there is provided a de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 89 to 97.9% by weight of polymerized units of acrylic acid or methacrylic acid and from 2 to 10% by weight of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group, and from 0.1 to 1%
by weight of a polymerized crosslinking agent, percentages by weight being based on the copolymer.
29374-64(S) - 5a -According to still another aspect of the present invention, there is provided a de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 75 to 98.99% by weight of polymerized units of acrylic acid or methacrylic acid, from 1 to 15o of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C2z alkyl radical in the ester group and one or two C6 to C2a alkyl radicals in the amide group and from 0.01 to 10% by weight of polymerized crosslinking agent, percentages by weight being based on the copolymer.
According to yet another aspect of the present invention, there is provided a de-icing and anti-icing composition consisting essentially of a) from 35 to 70% by weight of at least one glycol from the group comprising alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5% by weight of at least one water-soluble crosslinked copolymer as thickener, consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid with a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals :in the amide group in a minority amount, c) from 0.02 to 1.5% by weight of at least one surfactant from the group comprising fatty alcohol alkoxylates and arylalkylsulfonates, d) from 0.01 to to by weight of at least one corrosion inhibitor for liquids based on glycols and water, e) at least one basic compound for establishing a pH of from 7 to 11, and f) water as the remainder to 100% by weight, percentages by weight being based on the de-icing composition.
29374-64(S) - 5b -It has been found that water-soluble crosslinked copolymers of acrylic acid or methacrylic acid as principal monomer, and an ester or amide of acrylic acid or methacrylic acid having a long alkyl radical in the ester group and one or two long alkyl radicals in the amide group, as the secondary monomer, have a particularly pronounced pseudoplasticity and produce aircraft de-icing compositions of type II having the combination of properties called for above.
The thickener copolymer proposed in accordance with the invention therefore essentially comprises polymerized acrylic acid or methacrylic acid as principal constituent and a copolymerized ester or amide of acrylic acid or methacrylic acid, the ester compound containing a long alkyl radical and the amide compound containing one or two long alkyl radicals. A preferred copolymer essentially comprises from 85 to 99% by weight, preferably from 90 to 98% by weight (percentages by weight being based on the copolymer) of polymerized acrylic acid or methacrylic acid and from 1 to 15o by weight, preferably from 2 to 10% by weight, of polymerized ester compound or amide compound.
The alkyl radicals are preferably C6 to C22 alkyl, especially Clo to C18 alkyl and very particularly Clo to C14 alkyl. The ester monomers, accordingly, are of formulae (1) and (2) below ~1~'~046 -6_ //
CH2=CH-C ' (1) \0R1 //
CH2=C-C (2) \0R2 in which Rl and R2, which are identical or different, are each a long alkyl radical, preferably an alkyl radical having 6 to 22 carbon atoms, especially 10 to 18 carbon atoms and very particularly 10 to 14 carbon atoms, and the amide monomers are of formulae (3) and (4) below O
//
CH2=CH-C R3 (3) N
\R4 //
CH2=C-C R5 (4) N
\R6 in which R3 to R6, which are identical or different, are each a long alkyl radical, preferably an alkyl radical having 6 to 22 carbon atoms, especially 10 to 18 carbon atoms and very particularly 10 to 14 carbon atoms, and in which R4 and R6 may also be H or a short alkyl radical, preferably C1 to C4 alkyl. The alkyl radicals may be straight-chain or branched; they are preferably straight-chain. Of the two secondary monomers, the ester compounds are preferred.
_ 7 _ The aircraft de-icing composition according to the invention generally comprises from 0.05 to 1.5~ by weight, preferably from 0.1 to 1~ by weight, of at least one of the copolymers described, percentages by weight being based on the (ready-to-use) de-icing composition.
The copolymers to be employed in accordance with the invention are known and commercially available. They are prepared by copolymerization of the stated monomers in the presence of crosslinking agents. Copolymerization reactions of this kind are described in detail, for example, in US-A-4 744 913 which is mentioned at the outset. A further preparation method is based on first of all preparing an acrylic acid homopolymer or methacrylic acid homopolymer and then subjecting this homopolymer to the esterification or amidation indicated. It is self-evident that the principal monomer, acrylic acid or methacrylic acid, or else in the form of the corres-ponding acrylates, preferably alkali metal acrylates (the alkali metal is preferably potassium or sodium), can be polymerized with the secondary monomer, the ester or amide (acrylic acid and methacrylic acid are referred to alone only for the sake of simplicity). Here too, among the crosslinking agents mentioned in US-A-4 744 913, preference is given to those from the group consisting of polyunsaturated ethers, with particular preference being given to diallyl ethers, di- or triallyl glycerol ethers, di- or triallyl trimethylolethane ethers, di- or triallyl trimethylolpropane ethers, tetraallyloxyethane and di-, tri-, tetra-, penta- or hexaallyl ethers of sugar alcohols, and also the corresponding methallyl ethers.
The quantity of crosslinking agent in the copolymer is in general from 0.01 to 10~ by weight, preferably from 0.1 to l~ by weight, based on the copolymer. Accordingly, the water-soluble copolymer to be employed in accordance with the invention is essentially composed, with the inclusion of the quantity of crosslinking agent, of polymerized acrylic acid or methacrylic acid as principal constit-uent, of a smaller quantity of polymerized secondary ~1~'~04~
_$_ monomer and of a likewise smaller quantity of polymerized crosslinking agent. With the inclusion of the quantity of crosslinking agent, a preferred copolymer essentially comprises from 75 to 98.99% by weight, preferably from 89 to 97.9% by weight, of polymerized acrylic acid or methacrylic acid, from 1 to 15% by weight, preferably from 2 to 10% by weight, of polymerized ester compound or amide compound and from 0.01 to 10% by weight, preferably from 0.1 to 1% by weight, of polymerized crosslinking agent, percentages by weight being based on the (ready-to-use) copolymer.
The de-icing liquid according to the invention contains in particular, besides the thickener described, glycols and water and preferably also, in addition thereto, surfactants, corrosion inhibitors and, if required, pH
regulators for establishing a pH of from 7 to 11, preferably from 7.5 to 9.
The glycols present in the de-icing liquid according to the invention are preferably those from the group con-sisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms.
Preferred glycol compounds are ethylene glycol, propylene glycol (1,2-propylene glycol or 1,3-propylene glycol), diethylene glycol, dipropylene glycol or a mixture of two or more of these glycols, with particular preference being given to propylene glycols. The glycols are used in particular to lower the freezing point and, apart from water, constitute the majority component of the liquid.
The water employed is preferably deionized water.
As surfactants, fatty alcohol alkoxylates or arylalkyl-sulfonates or a mixture thereof are preferably employed.
The alkoxylate is preferably one having from 1 to 10, preferably from 1 to 5, ethylene oxide units, propylene oxide units or a mixure thereof, with ethylene oxide alone being preferred. The alkyl radical in the fatty alcohol generally contains 6 to 22 carbon atoms, _ g _ preferably 8 to 18 carbon atoms, and may be straight-chain or branched, preferably straight-chain, and may be saturated or unsaturated with preferably from 1 to 3 double bonds. Examples are octyl, decyl, dodecyl, isotri-decyl and stearyl alcohol, oleyl, coconut alkyl and tallow-alkyl alcohol and a fatty alcohol mixture with a C12 alkyl radical and a C14 alkyl radical (C12/Ci4 fatty alcohol) ethoxylated with from 1 to 5 mol of ethylene oxide. The alkarylsulfonate is preferably potassium and/or sodium alkylarylsulfonate having one or more, preferably one or two, sulfonate groups (S03R or S03Na groups), one or more, preferably one or two, alkyl groups of 5 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and one or more, preferably one or two, benzene rings. Preference is given to alkali metal (potassium and/or sodium) alkylbenzenesulfonates having 12 to 18 carbon atoms in the alkyl group. Since the preparation of alkylarylsulfonates also starts from mixtures of hydro-carbons, as are obtained, for example, as fractions in the processing of crude oil, the alkyl group may also constitute such mixtures. In this case the number of carbon atoms is preferably from 12 to 18 (that is, an average number of 15).
The corrosion inhibitors employed may be the compounds which are customary for liquids based on glycols and water. Suitable corrosion inhibitors are alkali metal phosphates, lower alkyl phosphates such as ethyl phos-phate, dimethyl phosphate, isopropyl phosphate and the like, imidazoles such as 1H-imidazole, methylimidazole, benzimidazole and the like and triazoles such as benzo-triazole and tolyltriazole, the triazoles being preferred.
In order to establish the pH of from 7 to 10, preferably from 7.5 to 9, use is made of basic compounds. Preference is given to those from the group consisting of alkali metal hydroxides such as NaOH and ROH, alkylamines such as butylamine, hexylamine, octylamine and isononylamine, ~14'~040 and alkanolamines such as mono-, di- and triethanolamine.
The alkali metal hydroxides are particularly preferred.
The de-icing and anti-icing composition according to the invention is prepared by mixing together the individual (known and co~ercially available) components in any desired order, which can be carried out, for example, in a vessel fitted with a stirrer.
Taking into account all of the components described above, the de-icing liquid according to the invention essentially comprises a) from 35 to 70~ by weight, preferably from 40 to 60~
by weight, of at least one glycol from the group consisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5o by weight, preferably from 0.1 to l~ by weight, of at least one water-soluble cross-linked copolymer of the type described, as thickener, c) from 0.02 to 1.5~ by weight, preferably from 0.05 to l~ by weight, of at least one surfactant from the group consisting of fatty alcohol alkoxylates and arylalkylsulfonates as described above, d) from 0.01 to l~ by weight, preferably from 0.03 to 0.7~ by weight, of at least one corrosion inhibitor for liquids based on glycols and water, e) at least one basic compound for establishing a pH of from 7 to 11, and f) water as the remainder to 100 by weight, percentages by Weight being based on the composition.
As mentioned above, the copolymer to be employed in accordance with the invention should be soluble in water.
It possesses water-solubility if the dissolution of up to 10 g of copolymer in 1000 g of water at about 20°C after establishing a pH of 7 with an alkali metal hydroxide produces a clear solution. As a further property, the ~14'~046 copolymer in a 0.2~ strength by weight aqueous solution at 20°C and with a pH of 7 (which is established with alkali metal hydroxide if such a pH is not present in any case) has a viscosity of from 1000 to 20,000 mPas, measured with a Brookfield viscometer at 20 revolutions per minute (rpm).
The type II de-icing liquid according to the invention easily meets the requirements set out above. Even if the de-icing liquid has a high viscosity at rest (yield value), which ensures a long holdover time, the new thickener achieves unexpectedly good flow-off character-istics. Using the novel thickener, therefore, it is possible to resolve the conflict between the two proper-ties of holdover time and flow-off characteristics. This surprising result apparently stems from the unexpectedly pronounced pseudoplastic behavior of the thickener described, which leads to a marked decrease in viscosity as shear increases and consequently to the low layer thicknesses required of the film of de-icing composition in the aerodynamic acceptance test.
The invention is illustrated in more detail by way of Examples 1 and 2 according to the invention and a compar-ison example, which follow.
Example 1 A type II aircraft de-icer having the following composi-tion was prepared in accordance with the procedure below:
50.00 ~ by weight of 1,2-propylene glycol 0.05 ~ by weight of benzotriazole 0.40 ~ by weight of sodium dodecylbenzenesulfonate 0.10 ~ by weight of fatty alcohol ethoxylate of 12 to 14 carbon atoms in the fatty alcohol and ethoxylated with 2 mol of ethylene oxide 0.30 ~ by weight of crosslinked acrylic acid-dodecyl methacrylate copolymer comprising 96.5% by weight of polymerized acrylic acid and 3.5% by weight of polymerized dodecyl methacrylate 0.093 % by weight of sodium hydroxide 0.019 % by weight of potassium hydroxide 49.038 % by weight of water.
The copolymer along with the benzotriazole and the surfactants were dissolved in water at 20°C by vigorous stirring. The 1,2-propylene glycol was then added and the pH was established at from 7 to 7.4 with sodium hydroxide and potassium hydroxide (in each case in the form of an approximately 10% strength by weight aqueous solution).
The de-icing composition obtained was tested in respect of viscosity, water-spray endurance time and boundary layer displacement thickness, d*, in the aerodynamic acceptance test. The results are compiled in Tables 1 and 2 below:
Table 1 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s-1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s-1.
Shear rate [s 1] 0.084 0.84 8.4 16.8 Viscosity [mPas] 5000 1500 630 500 2 Decrease in viscosity0 70.0 87 . 90 5 [ % ] 4 Table 2 Water spray endurance time and boundary layer displace-ment thickness, d*, in the aerodynamic acceptance test.
214'~0~6 Example 1 Requirements of ISO 11078 Water spray eaduraace time at -5C (mint 34 > 30 Boundary layer displacement thickness, d* at -30C (mm] 8.5 < 10.5 Boundary layer displacement thickness, d* at -10C (mm] 8.0 < 9.5 Example 2 A type II aircraft de-icer having the following composi-tion was prepared as in Example 1:
51.00 % by weight of 1,2-propyleneglycol 0.05 % by weight of tolyltriazole 0.40 % by weight of sodium dodecylbenzenesulfonate 0.33 % by weight of crosslinked acrylic acid-octadecyl methacrylate copolymer comprising 95% by weight of polymerized acrylic acid and 5% by weight of polymerized octadecyl methacrylate 0.118 % by weight of sodium hydroxide (in the form of an approximately 10% strength by weight solution) 48.102 % by weight of water.
The de-icing composition obtained (pH 7.2) was tested as in Example 1. The results are compiled in Tables 3 and 4 below:
Table 3 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s-1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s-1.
214'~~J4~
Shear rate Ls 1l 0.084 0.84 8.4 16.8 Viscosity ImPasl 7400 2450 910 680 Decrease in viscosity0 67.0 87.8 90.8 (XI
Table 4 Water spray endurance time and boundary layer displace-ment thickness, d*, in the aerodynamic acceptance test.
Example 2 Requirements of ISO 11078 Water spray endurance time at 34 > 30 -5C Imin) Boundary layer displacement thickness, d* at -30C Irtm1 10.0 < t0.5 1 Boundary layer displacement thickness, d* at -10C Cmm7 9.0 < 9.5 Comparison Example A type II aircraft de-icer having the following composi tion was prepared in accordance with the procedure below:
51.00 % by weight of 1,2-propylene glycol 0.05 % by weight of benzotriazole 0.40 % by weight of sodium dodecylbenzenesulfonate 0.10 % by weight of fatty alcohol ethoxylate of 12 to 14 carbon atoms in the fatty alcohol and ethoxylated with 2 mol of ethylene oxide 0.30 % by weight of crosslinked polyacrylic acid 0.086 % by weight of sodium hydroxide 0.017 % by weight of potassium hydroxide 48.047 % by weight of water.
The polyacrylic acid along with the benzotriazole and the surfactants were dissolved in water at 20°C by vigorous stirring. The 1,2-propylene glycol was then added and the pH was established at from 7 to 7.4 with sodium hydroxide and potassium hydroxide (in each case in the form of an ~14'~04~
approximately 10~ strength by weight aqueous solution).
The de-icing composition obtained was tested as in Example 1. The results are compiled in Tables 5 and 6 below:
Table 5 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s'1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s'1.
1 Shear rate [s-1] 0.084 0.84 8.4 16.8 Viscosity (mPae1 3800 1700 790 620 Decrease is viscosity0 55.3 79.2 83.7 (%]
Table 6 Water spray endurance time and boundary layer displace-meat thickness, d*, in the aerodynamic acceptance test.
Comparison Requirements Example of ISO 11078 f4ater spray endurance time at -5C [mint 34 > 30 Boundary layer displacement thickness, d* at -30C [mm] 12.0 < 10.5 Boundary layer displacement thickness, 2 a* at -toc (mm] la.o < 9.s
Further prior art is represented by the relatively recent document WO 93/24543, which describes linear or cross-linked polycarboxylates, containing specific macro-monomers, as thickeners for type II aircraft de-icing liquids. The macromonomer contains a hydrophobic terminal radical from the group of the alkaryls and is connected to the polycarboxylate (polyacrylate, polymethacrylate and the like) via a bridging link (see for example pages 9 and 19). This polymer thickener therefore requires monomers of relatively complex composition and can only be prepared over a plurality of reaction stages.
As mentioned above, the two properties of holdover time and flow-off characteristics are in conflict with one another. In order to achieve adequate flow-off character-istics, the chosen viscosity - and therefore the chosen concentration of thickener - must be as low as possible.
On the other hand, a sufficient holdover time requires a maximum yield value of the de-icing composition and thus, in general, a high viscosity and high concentration of thickener.
The object of the invention, accordingly, is to provide thickener polymers which are of simple composition and can be prepared easily and which bring about, in the ready-to-use aircraft de-icing composition, an increased pseudoplasticity - in other words, a greater decrease in viscosity under increasing shear stress - and which thereby, when subjected to shear stress and despite their high viscosity at rest, become mobile markedly more quickly and thus flow off better. The novel de-icing composition of enhanced pseudoplasticity should pass the 29374-64(S) water spray endurance test owing to its adequate viscosity at rest and should at the same time, owing to faster flow-off in the wind tunnel or on takeoff, attain the low values required for the boundary layer displacement thickness in the aerodynamic acceptance test. The novel type II aircraft de-icing composition should therefore be based on a simple and readily accessible polymer thickener and should easily fulfill the requirements of ISO Standard 11078 with regard to holdover time and flow-off characteristics.
According to one aspect of the present invention, there is provided a de-icing and anti-icing composition for aircraft which is based on glycols and water and contains water-soluble crosslinked acrylic polymers as thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the 2o amide group in a minority amount.
According to another aspect of the present invention, there is provided a de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 89 to 97.9% by weight of polymerized units of acrylic acid or methacrylic acid and from 2 to 10% by weight of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group, and from 0.1 to 1%
by weight of a polymerized crosslinking agent, percentages by weight being based on the copolymer.
29374-64(S) - 5a -According to still another aspect of the present invention, there is provided a de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 75 to 98.99% by weight of polymerized units of acrylic acid or methacrylic acid, from 1 to 15o of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C2z alkyl radical in the ester group and one or two C6 to C2a alkyl radicals in the amide group and from 0.01 to 10% by weight of polymerized crosslinking agent, percentages by weight being based on the copolymer.
According to yet another aspect of the present invention, there is provided a de-icing and anti-icing composition consisting essentially of a) from 35 to 70% by weight of at least one glycol from the group comprising alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5% by weight of at least one water-soluble crosslinked copolymer as thickener, consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid with a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals :in the amide group in a minority amount, c) from 0.02 to 1.5% by weight of at least one surfactant from the group comprising fatty alcohol alkoxylates and arylalkylsulfonates, d) from 0.01 to to by weight of at least one corrosion inhibitor for liquids based on glycols and water, e) at least one basic compound for establishing a pH of from 7 to 11, and f) water as the remainder to 100% by weight, percentages by weight being based on the de-icing composition.
29374-64(S) - 5b -It has been found that water-soluble crosslinked copolymers of acrylic acid or methacrylic acid as principal monomer, and an ester or amide of acrylic acid or methacrylic acid having a long alkyl radical in the ester group and one or two long alkyl radicals in the amide group, as the secondary monomer, have a particularly pronounced pseudoplasticity and produce aircraft de-icing compositions of type II having the combination of properties called for above.
The thickener copolymer proposed in accordance with the invention therefore essentially comprises polymerized acrylic acid or methacrylic acid as principal constituent and a copolymerized ester or amide of acrylic acid or methacrylic acid, the ester compound containing a long alkyl radical and the amide compound containing one or two long alkyl radicals. A preferred copolymer essentially comprises from 85 to 99% by weight, preferably from 90 to 98% by weight (percentages by weight being based on the copolymer) of polymerized acrylic acid or methacrylic acid and from 1 to 15o by weight, preferably from 2 to 10% by weight, of polymerized ester compound or amide compound.
The alkyl radicals are preferably C6 to C22 alkyl, especially Clo to C18 alkyl and very particularly Clo to C14 alkyl. The ester monomers, accordingly, are of formulae (1) and (2) below ~1~'~046 -6_ //
CH2=CH-C ' (1) \0R1 //
CH2=C-C (2) \0R2 in which Rl and R2, which are identical or different, are each a long alkyl radical, preferably an alkyl radical having 6 to 22 carbon atoms, especially 10 to 18 carbon atoms and very particularly 10 to 14 carbon atoms, and the amide monomers are of formulae (3) and (4) below O
//
CH2=CH-C R3 (3) N
\R4 //
CH2=C-C R5 (4) N
\R6 in which R3 to R6, which are identical or different, are each a long alkyl radical, preferably an alkyl radical having 6 to 22 carbon atoms, especially 10 to 18 carbon atoms and very particularly 10 to 14 carbon atoms, and in which R4 and R6 may also be H or a short alkyl radical, preferably C1 to C4 alkyl. The alkyl radicals may be straight-chain or branched; they are preferably straight-chain. Of the two secondary monomers, the ester compounds are preferred.
_ 7 _ The aircraft de-icing composition according to the invention generally comprises from 0.05 to 1.5~ by weight, preferably from 0.1 to 1~ by weight, of at least one of the copolymers described, percentages by weight being based on the (ready-to-use) de-icing composition.
The copolymers to be employed in accordance with the invention are known and commercially available. They are prepared by copolymerization of the stated monomers in the presence of crosslinking agents. Copolymerization reactions of this kind are described in detail, for example, in US-A-4 744 913 which is mentioned at the outset. A further preparation method is based on first of all preparing an acrylic acid homopolymer or methacrylic acid homopolymer and then subjecting this homopolymer to the esterification or amidation indicated. It is self-evident that the principal monomer, acrylic acid or methacrylic acid, or else in the form of the corres-ponding acrylates, preferably alkali metal acrylates (the alkali metal is preferably potassium or sodium), can be polymerized with the secondary monomer, the ester or amide (acrylic acid and methacrylic acid are referred to alone only for the sake of simplicity). Here too, among the crosslinking agents mentioned in US-A-4 744 913, preference is given to those from the group consisting of polyunsaturated ethers, with particular preference being given to diallyl ethers, di- or triallyl glycerol ethers, di- or triallyl trimethylolethane ethers, di- or triallyl trimethylolpropane ethers, tetraallyloxyethane and di-, tri-, tetra-, penta- or hexaallyl ethers of sugar alcohols, and also the corresponding methallyl ethers.
The quantity of crosslinking agent in the copolymer is in general from 0.01 to 10~ by weight, preferably from 0.1 to l~ by weight, based on the copolymer. Accordingly, the water-soluble copolymer to be employed in accordance with the invention is essentially composed, with the inclusion of the quantity of crosslinking agent, of polymerized acrylic acid or methacrylic acid as principal constit-uent, of a smaller quantity of polymerized secondary ~1~'~04~
_$_ monomer and of a likewise smaller quantity of polymerized crosslinking agent. With the inclusion of the quantity of crosslinking agent, a preferred copolymer essentially comprises from 75 to 98.99% by weight, preferably from 89 to 97.9% by weight, of polymerized acrylic acid or methacrylic acid, from 1 to 15% by weight, preferably from 2 to 10% by weight, of polymerized ester compound or amide compound and from 0.01 to 10% by weight, preferably from 0.1 to 1% by weight, of polymerized crosslinking agent, percentages by weight being based on the (ready-to-use) copolymer.
The de-icing liquid according to the invention contains in particular, besides the thickener described, glycols and water and preferably also, in addition thereto, surfactants, corrosion inhibitors and, if required, pH
regulators for establishing a pH of from 7 to 11, preferably from 7.5 to 9.
The glycols present in the de-icing liquid according to the invention are preferably those from the group con-sisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms.
Preferred glycol compounds are ethylene glycol, propylene glycol (1,2-propylene glycol or 1,3-propylene glycol), diethylene glycol, dipropylene glycol or a mixture of two or more of these glycols, with particular preference being given to propylene glycols. The glycols are used in particular to lower the freezing point and, apart from water, constitute the majority component of the liquid.
The water employed is preferably deionized water.
As surfactants, fatty alcohol alkoxylates or arylalkyl-sulfonates or a mixture thereof are preferably employed.
The alkoxylate is preferably one having from 1 to 10, preferably from 1 to 5, ethylene oxide units, propylene oxide units or a mixure thereof, with ethylene oxide alone being preferred. The alkyl radical in the fatty alcohol generally contains 6 to 22 carbon atoms, _ g _ preferably 8 to 18 carbon atoms, and may be straight-chain or branched, preferably straight-chain, and may be saturated or unsaturated with preferably from 1 to 3 double bonds. Examples are octyl, decyl, dodecyl, isotri-decyl and stearyl alcohol, oleyl, coconut alkyl and tallow-alkyl alcohol and a fatty alcohol mixture with a C12 alkyl radical and a C14 alkyl radical (C12/Ci4 fatty alcohol) ethoxylated with from 1 to 5 mol of ethylene oxide. The alkarylsulfonate is preferably potassium and/or sodium alkylarylsulfonate having one or more, preferably one or two, sulfonate groups (S03R or S03Na groups), one or more, preferably one or two, alkyl groups of 5 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and one or more, preferably one or two, benzene rings. Preference is given to alkali metal (potassium and/or sodium) alkylbenzenesulfonates having 12 to 18 carbon atoms in the alkyl group. Since the preparation of alkylarylsulfonates also starts from mixtures of hydro-carbons, as are obtained, for example, as fractions in the processing of crude oil, the alkyl group may also constitute such mixtures. In this case the number of carbon atoms is preferably from 12 to 18 (that is, an average number of 15).
The corrosion inhibitors employed may be the compounds which are customary for liquids based on glycols and water. Suitable corrosion inhibitors are alkali metal phosphates, lower alkyl phosphates such as ethyl phos-phate, dimethyl phosphate, isopropyl phosphate and the like, imidazoles such as 1H-imidazole, methylimidazole, benzimidazole and the like and triazoles such as benzo-triazole and tolyltriazole, the triazoles being preferred.
In order to establish the pH of from 7 to 10, preferably from 7.5 to 9, use is made of basic compounds. Preference is given to those from the group consisting of alkali metal hydroxides such as NaOH and ROH, alkylamines such as butylamine, hexylamine, octylamine and isononylamine, ~14'~040 and alkanolamines such as mono-, di- and triethanolamine.
The alkali metal hydroxides are particularly preferred.
The de-icing and anti-icing composition according to the invention is prepared by mixing together the individual (known and co~ercially available) components in any desired order, which can be carried out, for example, in a vessel fitted with a stirrer.
Taking into account all of the components described above, the de-icing liquid according to the invention essentially comprises a) from 35 to 70~ by weight, preferably from 40 to 60~
by weight, of at least one glycol from the group consisting of alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5o by weight, preferably from 0.1 to l~ by weight, of at least one water-soluble cross-linked copolymer of the type described, as thickener, c) from 0.02 to 1.5~ by weight, preferably from 0.05 to l~ by weight, of at least one surfactant from the group consisting of fatty alcohol alkoxylates and arylalkylsulfonates as described above, d) from 0.01 to l~ by weight, preferably from 0.03 to 0.7~ by weight, of at least one corrosion inhibitor for liquids based on glycols and water, e) at least one basic compound for establishing a pH of from 7 to 11, and f) water as the remainder to 100 by weight, percentages by Weight being based on the composition.
As mentioned above, the copolymer to be employed in accordance with the invention should be soluble in water.
It possesses water-solubility if the dissolution of up to 10 g of copolymer in 1000 g of water at about 20°C after establishing a pH of 7 with an alkali metal hydroxide produces a clear solution. As a further property, the ~14'~046 copolymer in a 0.2~ strength by weight aqueous solution at 20°C and with a pH of 7 (which is established with alkali metal hydroxide if such a pH is not present in any case) has a viscosity of from 1000 to 20,000 mPas, measured with a Brookfield viscometer at 20 revolutions per minute (rpm).
The type II de-icing liquid according to the invention easily meets the requirements set out above. Even if the de-icing liquid has a high viscosity at rest (yield value), which ensures a long holdover time, the new thickener achieves unexpectedly good flow-off character-istics. Using the novel thickener, therefore, it is possible to resolve the conflict between the two proper-ties of holdover time and flow-off characteristics. This surprising result apparently stems from the unexpectedly pronounced pseudoplastic behavior of the thickener described, which leads to a marked decrease in viscosity as shear increases and consequently to the low layer thicknesses required of the film of de-icing composition in the aerodynamic acceptance test.
The invention is illustrated in more detail by way of Examples 1 and 2 according to the invention and a compar-ison example, which follow.
Example 1 A type II aircraft de-icer having the following composi-tion was prepared in accordance with the procedure below:
50.00 ~ by weight of 1,2-propylene glycol 0.05 ~ by weight of benzotriazole 0.40 ~ by weight of sodium dodecylbenzenesulfonate 0.10 ~ by weight of fatty alcohol ethoxylate of 12 to 14 carbon atoms in the fatty alcohol and ethoxylated with 2 mol of ethylene oxide 0.30 ~ by weight of crosslinked acrylic acid-dodecyl methacrylate copolymer comprising 96.5% by weight of polymerized acrylic acid and 3.5% by weight of polymerized dodecyl methacrylate 0.093 % by weight of sodium hydroxide 0.019 % by weight of potassium hydroxide 49.038 % by weight of water.
The copolymer along with the benzotriazole and the surfactants were dissolved in water at 20°C by vigorous stirring. The 1,2-propylene glycol was then added and the pH was established at from 7 to 7.4 with sodium hydroxide and potassium hydroxide (in each case in the form of an approximately 10% strength by weight aqueous solution).
The de-icing composition obtained was tested in respect of viscosity, water-spray endurance time and boundary layer displacement thickness, d*, in the aerodynamic acceptance test. The results are compiled in Tables 1 and 2 below:
Table 1 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s-1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s-1.
Shear rate [s 1] 0.084 0.84 8.4 16.8 Viscosity [mPas] 5000 1500 630 500 2 Decrease in viscosity0 70.0 87 . 90 5 [ % ] 4 Table 2 Water spray endurance time and boundary layer displace-ment thickness, d*, in the aerodynamic acceptance test.
214'~0~6 Example 1 Requirements of ISO 11078 Water spray eaduraace time at -5C (mint 34 > 30 Boundary layer displacement thickness, d* at -30C (mm] 8.5 < 10.5 Boundary layer displacement thickness, d* at -10C (mm] 8.0 < 9.5 Example 2 A type II aircraft de-icer having the following composi-tion was prepared as in Example 1:
51.00 % by weight of 1,2-propyleneglycol 0.05 % by weight of tolyltriazole 0.40 % by weight of sodium dodecylbenzenesulfonate 0.33 % by weight of crosslinked acrylic acid-octadecyl methacrylate copolymer comprising 95% by weight of polymerized acrylic acid and 5% by weight of polymerized octadecyl methacrylate 0.118 % by weight of sodium hydroxide (in the form of an approximately 10% strength by weight solution) 48.102 % by weight of water.
The de-icing composition obtained (pH 7.2) was tested as in Example 1. The results are compiled in Tables 3 and 4 below:
Table 3 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s-1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s-1.
214'~~J4~
Shear rate Ls 1l 0.084 0.84 8.4 16.8 Viscosity ImPasl 7400 2450 910 680 Decrease in viscosity0 67.0 87.8 90.8 (XI
Table 4 Water spray endurance time and boundary layer displace-ment thickness, d*, in the aerodynamic acceptance test.
Example 2 Requirements of ISO 11078 Water spray endurance time at 34 > 30 -5C Imin) Boundary layer displacement thickness, d* at -30C Irtm1 10.0 < t0.5 1 Boundary layer displacement thickness, d* at -10C Cmm7 9.0 < 9.5 Comparison Example A type II aircraft de-icer having the following composi tion was prepared in accordance with the procedure below:
51.00 % by weight of 1,2-propylene glycol 0.05 % by weight of benzotriazole 0.40 % by weight of sodium dodecylbenzenesulfonate 0.10 % by weight of fatty alcohol ethoxylate of 12 to 14 carbon atoms in the fatty alcohol and ethoxylated with 2 mol of ethylene oxide 0.30 % by weight of crosslinked polyacrylic acid 0.086 % by weight of sodium hydroxide 0.017 % by weight of potassium hydroxide 48.047 % by weight of water.
The polyacrylic acid along with the benzotriazole and the surfactants were dissolved in water at 20°C by vigorous stirring. The 1,2-propylene glycol was then added and the pH was established at from 7 to 7.4 with sodium hydroxide and potassium hydroxide (in each case in the form of an ~14'~04~
approximately 10~ strength by weight aqueous solution).
The de-icing composition obtained was tested as in Example 1. The results are compiled in Tables 5 and 6 below:
Table 5 Viscosity values at 0°C and 0.084, 0.84, 8.4 and 16.8 s'1 shear rate and decrease in viscosity at the ascending shear rates indicated, expressed in percent based on the viscosity value at a shear rate of 0.084 s'1.
1 Shear rate [s-1] 0.084 0.84 8.4 16.8 Viscosity (mPae1 3800 1700 790 620 Decrease is viscosity0 55.3 79.2 83.7 (%]
Table 6 Water spray endurance time and boundary layer displace-meat thickness, d*, in the aerodynamic acceptance test.
Comparison Requirements Example of ISO 11078 f4ater spray endurance time at -5C [mint 34 > 30 Boundary layer displacement thickness, d* at -30C [mm] 12.0 < 10.5 Boundary layer displacement thickness, 2 a* at -toc (mm] la.o < 9.s
Claims (9)
1. A de-icing and anti-icing composition for aircraft which is based on glycols and water and contains water-soluble crosslinked acrylic polymers as thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group in a minority amount.
2. A de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 89 to 97.9% by weight of polymerized units of acrylic acid or methacrylic acid and from 2 to 10% by weight of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group, and from 0.1 to 1% by weight of a polymerized crosslinking agent, percentages by weight being based on the copolymer.
3. A de-icing and anti-icing composition comprising water, a glycol and a thickener, wherein the thickener is a water-soluble crosslinked copolymer consisting essentially of from 75 to 98.99% by weight of polymerized units of acrylic acid or methacrylic acid, from 1 to 15% of polymerized units of an ester or amide of acrylic acid or methacrylic acid having a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group and from 0.01 to 10% by weight of polymerized crosslinking agent, percentages by weight being based on the copolymer.
4. The composition as claimed in any one of claims 1 to 3, wherein the alkyl radical or the alkyl radicals has or each have 10 to 18 carbon atoms.
5. The composition as claimed in any one of claims 1 to 4, comprising from 0.05 to 1.5% by weight of the water-soluble crosslinked copolymer, percentages by weight being based on the de-icing composition.
6. The composition as claimed in any one of claims 1 to 5, additionally comprising at least one surfactant from the group comprising fatty alcohol alkoxylates and arylalkylsulfonates, at least one corrosion inhibitor for a liquid based on a glycol and water and at least one basic compound for establishing a pH of from 7 to 11.
7. A de-icing and anti-icing composition consisting essentially of a) from 35 to 70% by weight of at least one glycol from the group comprising alkylene glycols having 2 or 3 carbon atoms and oxyalkylene glycols having 4 to 6 carbon atoms, b) from 0.05 to 1.5% by weight of at least one water-soluble crosslinked copolymer as thickener, consisting essentially of polymerized units of acrylic acid or methacrylic acid in a majority amount and polymerized units of an ester or amide of acrylic acid or methacrylic acid with a C6 to C22 alkyl radical in the ester group and one or two C6 to C22 alkyl radicals in the amide group in a minority amount, c) from 0.02 to 1.5% by weight of at least one surfactant from the group comprising fatty alcohol alkoxylates and arylalkylsulfonates, d) from 0.01 to 1% by weight of at least one corrosion inhibitor for liquids based on glycols and water, e) at least one basic compound for establishing a pH of from 7 to 11, and f) water as the remainder to 100% by weight, percentages by weight being based on the de-icing composition.
8. The composition as claimed in claim 7, wherein the fatty alcohol alkoxylate is a fatty alcohol ethoxylate having 1 to 10 ethylene oxide units.
9. The composition as claimed in claim 7, wherein the alkyl radical or the alkyl radicals in the ester or amide has or each have 10 to 18 carbon atoms and the fatty alcohol alkoxylate is a fatty alcohol ethoxylate having 1 to 5 ethylene oxide units.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4412790A DE4412790A1 (en) | 1994-04-14 | 1994-04-14 | Polymer-thickened deicing agent and anti-icing agent for aircraft |
| DEP4412790.1 | 1994-04-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2147046A1 CA2147046A1 (en) | 1995-10-15 |
| CA2147046C true CA2147046C (en) | 2003-12-02 |
Family
ID=6515335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002147046A Expired - Lifetime CA2147046C (en) | 1994-04-14 | 1995-04-13 | Polymer-thickened de-icing and anti-icing composition for aircraft |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0678565B1 (en) |
| JP (1) | JP3977876B2 (en) |
| CA (1) | CA2147046C (en) |
| DE (2) | DE4412790A1 (en) |
| DK (1) | DK0678565T3 (en) |
| FI (1) | FI112246B (en) |
| NO (1) | NO311893B1 (en) |
| RU (1) | RU2137797C1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101831275A (en) * | 2010-05-24 | 2010-09-15 | 陕西高科理化技术有限公司 | Polymer-thickened non-Newton aircraft deicing/anti-icing liquid |
| US8309667B2 (en) | 2005-11-14 | 2012-11-13 | Sumitomo Seika Chemicals Co., Ltd. | Water-soluble copolymer having alkyl-modified carboxyl groups |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19538607A1 (en) * | 1995-10-18 | 1997-04-24 | Hoechst Ag | Polymer thickened deicing and anti-icing agent for aircraft |
| US5750047A (en) * | 1997-03-13 | 1998-05-12 | The B.F. Goodrich Company | Anti-icing fluids |
| DE19816796A1 (en) * | 1998-04-16 | 1999-10-21 | Clariant Gmbh | Anti-icing agents for aircraft |
| DE19836808A1 (en) * | 1998-08-14 | 2000-02-24 | Basf Ag | Thickener for surfactant-containing compositions |
| JP4809557B2 (en) * | 2001-09-28 | 2011-11-09 | 成田国際空港株式会社 | How to recycle and reuse antifreeze liquid |
| GB0605235D0 (en) * | 2006-03-15 | 2006-04-26 | Kilfrost Ltd | Aircraft-de-/anti-icer |
| DE102006040122B3 (en) * | 2006-08-26 | 2007-10-31 | Degussa Gmbh | De-icing- or antifreezing agent, useful to remove frozen precipitations such as ice and snows from surfaces, comprises glycol, dentritic polymer, thickening agent and water |
| RU2525553C1 (en) * | 2013-06-25 | 2014-08-20 | Общество с ограниченной ответственностью "АВИАФЛЮИД Интернешнл" | Method of step-by-step obtaining composition of thickener of anti-icing liquid and thickener composition |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1901061A1 (en) * | 1969-01-10 | 1970-08-20 | Huels Chemische Werke Ag | Deicing fluid for aircraft surfaces |
| FR2057577A5 (en) * | 1969-08-28 | 1971-05-21 | Gusudarstvenny N | Anti-icing solns with increased viscosity |
| DE3635721A1 (en) * | 1986-02-06 | 1987-08-13 | Hoechst Ag | DEFROST AND ICE PROTECTION AGENTS FOR AIRCRAFT |
| FR2623516B1 (en) * | 1987-11-19 | 1994-04-15 | Saint Gobain Vitrage | COMPOSITION FOR ANTI-FOG COATING, PRODUCT COATED WITH THIS COMPOSITION AND PROCESS FOR PREPARING THE SAME |
| DE3832310A1 (en) * | 1988-09-23 | 1990-04-05 | Basf Ag | De-icing agent BZW. EXTRACTION PROTECTION FOR PLANES |
| US5118435A (en) * | 1990-11-19 | 1992-06-02 | Texaco Chemical Company | Anti-icing compositions containing thickener blend having polyacrylic acid and copolymer of acrylic acid and hydrophobic vinyl monomer |
-
1994
- 1994-04-14 DE DE4412790A patent/DE4412790A1/en not_active Withdrawn
-
1995
- 1995-04-08 DK DK95105348T patent/DK0678565T3/en active
- 1995-04-08 DE DE59505066T patent/DE59505066D1/en not_active Expired - Lifetime
- 1995-04-08 EP EP95105348A patent/EP0678565B1/en not_active Expired - Lifetime
- 1995-04-12 FI FI951763A patent/FI112246B/en not_active IP Right Cessation
- 1995-04-12 NO NO19951437A patent/NO311893B1/en not_active IP Right Cessation
- 1995-04-12 RU RU95105884/04A patent/RU2137797C1/en active
- 1995-04-13 JP JP08846095A patent/JP3977876B2/en not_active Expired - Lifetime
- 1995-04-13 CA CA002147046A patent/CA2147046C/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8309667B2 (en) | 2005-11-14 | 2012-11-13 | Sumitomo Seika Chemicals Co., Ltd. | Water-soluble copolymer having alkyl-modified carboxyl groups |
| CN101831275A (en) * | 2010-05-24 | 2010-09-15 | 陕西高科理化技术有限公司 | Polymer-thickened non-Newton aircraft deicing/anti-icing liquid |
Also Published As
| Publication number | Publication date |
|---|---|
| NO951437L (en) | 1995-10-16 |
| DE59505066D1 (en) | 1999-03-25 |
| CA2147046A1 (en) | 1995-10-15 |
| JPH0848970A (en) | 1996-02-20 |
| DK0678565T3 (en) | 2000-04-17 |
| FI112246B (en) | 2003-11-14 |
| FI951763A (en) | 1995-10-15 |
| FI951763A0 (en) | 1995-04-12 |
| NO951437D0 (en) | 1995-04-12 |
| EP0678565A1 (en) | 1995-10-25 |
| DE4412790A1 (en) | 1995-10-19 |
| EP0678565B1 (en) | 1999-02-10 |
| RU2137797C1 (en) | 1999-09-20 |
| RU95105884A (en) | 1997-03-20 |
| JP3977876B2 (en) | 2007-09-19 |
| NO311893B1 (en) | 2002-02-11 |
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