Anti-icing composition and method of preventing icing

This invention provides: PA1 (A) an anti-icing composition comprising a silicone resin which is at least one condensate selected from the group consisting of: PA2 (i) a condensate of an alkoxydimethylsiloxane compound represented by the formula ##STR1## wherein R.sub.1 l is a methyl group or an ethyl group, A is an oxygen atom, an ethylene group or a 1,3-propylene group, a is an integer of 5 to 150, b and e are different or the same and each represent an integer of 1 to 3, c is an integer of 3-b and d is an integer of 3-e, PA2 (ii) a condensate of the compound of the formula (I) and an alkoxysilane compound represented by the formula EQU (R.sub.3)h--Si--(OR.sub.2)j (II) PA2 wherein R.sub.2 is a methyl group or an ethyl group, R.sub.3 is an alkyl group having 1 to 8 carbon atoms, h is an integer of 0 to 3 and j is an integer of 4-h, PA2 (iii) a condensate of the compound of the formula (I) and a dihydroxydimethylsiloxane compound represented by the formula ##STR2## wherein k is an integer of 10 to 200, and (iv) a condensate of the compound of the formula (I), the alkoxysilane compound of the formula (II) and the dihydroxydimethylsiloxane compound of the formula (III); and PA1 (B) a method of preventing icing which comprises applying to an article an aerosol comprising the foregoing anti-icing composition and a propellant.

The present invention relates to a novel anti-icing composition and a novel 
method of preventing icing. 
Ice-thawing agents are commercially available which comprise an ethylene 
glycol or like alcohol, a surfactant, a propellant such as carbon dioxide 
gas or LPG and the like. In use, such ice-thawing agent is sprayed to 
temporarily thaw the ice on an article as on portions of automobiles such 
as windshield glass, wiper, mirror, tire housing, keyholes and the like. 
However, these commercially available ice-thawing agents are intended to 
temporarily thaw the ice on an article and are unable to sustain the 
effect. Further the ice-thawing agent applied to an article can not 
prevent icing thereon. Generally an ice coating formed on an article 
exhibits an icing strength of less than about 1 kg/cm.sup.2 when forcedly 
separated from the article without use of a spatula, hammer, stick or the 
like. On the other hand, the portion of the ice-thawing agent sprayed and 
left on an article shows an icing strength of over 1 kg/cm.sup.2 when 
frozen into ice. In other words, the commercial ice-thawing agent has the 
further drawback of being formed into ice having a higher icing strength 
unless the active component in the agent is completely removed by 
thoroughly washing the sprayed agent with water. 
Japanese Unexamined Patent Publication No.185776/1987 discloses a 
defrosting and anti-icing composition comprising a homopolymer of glycol, 
acrylic acid or alkali metal acrylate, an acrylamide/acrylic acid 
copolymer or an acrylamide/alkali metal acrylate copolymer, an alkali 
metal alkylarylsulfonate, a corrosion inhibitor, three kinds of basic 
compounds for adjusting the pH and water. The disclosed composition is 
effective in defrosting or preventing icing on an article subjected to 
shear force as on aircraft taking off, but is unsatisfactory in removing 
ice or preventing icing on a stationary article. 
It is an object of the present invention to provide a novel anti-icing 
composition which is formed into ice with an icing strength of up to about 
1 kg/cm.sup.2 and which is capable of easily removing ice, and a method of 
preventing icing with the composition. 
It is another object of the invention to provide a novel anti-icing 
composition which can sustain an excellent anti-icing effect over a 
prolonged period, and a method of preventing icing with the composition. 
These and other objects of the invention will become apparent from the 
following description. 
According to the present invention, there is provided an anti-icing 
composition comprising a silicone resin which is at least one condensate 
selected from the group consisting of: 
(i) a condensate of an alkoxydimethylsiloxane compound represented by the 
formula 
##STR3## 
wherein R.sub.1 is a methyl group or an ethyl group, A is an oxygen atom, 
an ethylene group or a 1,3-propylene group, a is an integer of 5 to 150, b 
and e are different or the same and each represent an integer of 1 to 3, c 
is an integer of 3-b and d is an integer of 3-e, 
(ii) a condensate of the compound of the formula (I) and an alkoxysilane 
compound represented by the formula 
EQU (R.sub.3)h--Si--(OR.sub.2)j (II) 
wherein R.sub.2 is a methyl group or an ethyl group, R.sub.3 is an alkyl 
group having 1 to 8 carbon atoms, h is an integer of 0 to 3 and j is an 
integer of 4-h, 
(iii) a condensate of the compound of the formula (I) and a 
dihydroxydimethylsiloxane compound represented by the formula 
##STR4## 
wherein k is an integer of 10 to 200, and (iv) a condensate of the 
compound of the formula (I), the alkoxysilane compound of the formula (II) 
and the dihydroxydimethylsiloxane compound of the formula (III). 
These silicone resins (i) to (iv) will be hereinafter referred to each as 
"condensation silicone resin". 
According to the invention, there is also provided an anti-icing 
composition comprising the condensation silicone resin and a 
moisture-curable film-forming resin. 
According to the invention, there is further provided a method of 
preventing icing which comprises applying onto an article an aerosol 
containing the anti-icing composition and a propellant. 
Concentrating on the specific properties of dimethylpolysiloxane (silicone 
oil) of being hydrophobic and having low surface energy, we investigated 
and found that with a low cohesive strength, the silicone oil is removed 
together with ice and is unable to sustain its low icing strength. Then we 
conducted extensive research on anti-icing compositions prepared utilizing 
the advantage of low icing strength due to dimethylpolysiloxane chains and 
capable of being formed into ice retaining a low icing strength. Our 
research revealed that a composition containing a condensation product 
prepared from a specific alkoxydimethylsiloxane compound can achieve the 
foregoing objects. 
The present invention has been accomplished on the basis of this novel 
finding. 
The condensation silicone resin for use in the invention is at least one 
condensate selected from (i) the condensate of the alkoxydimethylsiloxane 
compound of the formula (I) (hereinafter referred to as "compound (I)"), 
(ii) the condensate of the compound (I) and the alkoxysilane compound of 
the formula (II), (iii) the condensate of the compound (I) and the 
dihydroxydimethylsiloxane compound of the formula (III) and (iv) the 
condensate of the compound (I), the alkoxysilane of the formula (II) and 
the dihydroxydimethylsiloxane of the formula (III). These condensation 
siloxane resins predominantly contain hydrophobic dimethylsiloxane chains 
and are preferably comb-shaped condensates having hydrophobic 
dimethylsiloxane chains as the side chains. 
The condensates (i) and (ii) are prepared by partially hydrolytic 
condensation or co-condensation reaction. The reaction for forming the 
condensate (ii) is typically illustrated by the following reaction scheme. 
##STR5## 
The condensates (iii) and (iv) can be prepared by the same method as 
above, i.e. by partially hydrolytic cocondensation reaction, and can be 
optionally prepared without hydrolysis. For example, the condensate (iii) 
is obtained according to the following reaction scheme. 
##STR6## 
In the reaction between the compound (I) and the alkoxysilane of the 
formula (II) for giving the condensate (ii), it is preferred to use about 
30% by weight or less of the alkoxysilane of the formula (II) based on the 
combined amount of both compounds. If over 30% by weight of the 
alkoxysilane of the formula (II) is used, the alkoxy group as the polar 
group or the hydrolyzed silanol group readily remain, resulting in 
increase of icing strength. 
In the reaction between the compound (I) and the dihydroxydimethylsiloxane 
of the formula (III) for giving the condensate (iii), the 
dihydroxydimethylsiloxane of the formula (III) is used in an amount of 
preferably about 80% by weight or less, more preferably about 20 to about 
70% by weight, based on the combined amount of both compounds. If more 
than 80% by weight of the dihydroxydimethylsiloxane of the formula (III) 
is used, the unreacted silanol group readily remains in large quantity, 
leading to increase of icing strength. 
In the reaction for providing the condensate (iv), it is suitable to use 
about 20% by weight or more, preferably about 30 to about 70% by weight, 
of the compound (I); about 30% by weight or less, preferably about 20% by 
weight or less of the alkoxysilane of the formula (II); and about 80% by 
weight or less, preferably about 30 to about 70% by weight, of the 
dihydroxydimethylsiloxane of the formula (III), all based on the combined 
amount of the three compounds. 
With less than 20% by weight of the compound (I) used, the amount of 
hydrophobic polydimethylsiloxane chains as the side chains is reduced, 
resulting in increase of icing strength. 
With more than 30% by weight of the alkoxysilane of the formula (II) used, 
the alkoxy group and the hydrolyzed silanol group both as polar groups 
readily remain, causing the increase of icing strength. 
With over 80% by weight of the dihydroxydimethylsiloxane of the formula 
(III) used, the unreacted silanol group readily remains in large amount, 
leading to increase of icing strength. 
According to the invention, the condensation silicone resin for the 
composition of the invention is prepared by condensing at least one 
compound (I), or by co-condensing the compound (I), the alkoxysilane of 
the formula (II) and/or the dihydroxydimethylsiloxane of the formula 
(III). For the preparation of the condensation silicone resin, it is 
desirable to suitably select the kind of starting materials, mixing ratio, 
kind of reaction catalyst, amount of catalyst, reaction temperature and 
reaction time so that the resulting condensation silicone resin has a 
weight average molecular weight of about 15,000 to about 200,000, 
preferably about 20,000 to about 150,000. Examples of useful reaction 
catalysts are mineral acids such as hydrochloric acid, sulfuric acid and 
the like; organic acids such as formic acid, acetic acid and the like; 
acetylacetone complexes of manganese, cobalt, lead, nickel, iron, tin, 
zinc or like metals; stearic acid salt, octylic acid salt or like fatty 
acid salts of the above-mentioned metals; etc. The reaction catalyst is 
used usually in an amount of about 0.001 to about 1 part by weight per 100 
parts by weight of the silicone compounds of the formulas (I) to (III) as 
combined. The condensation reaction is carried out at a temperature of 
about 50 to about 150.degree. C for about 30 minutes to about 10 hours. 
According to the invention, the condensation silicone resin is used singly 
or in mixture with an organic solvent, or preferably in mixture with a 
moisturecurable film-forming resin to give a film with improved strength 
and a higher adhesion to the substrate, consequently with an enhanced 
ability to sustain the antiicing effect for a long term. 
A suitable ratio of the condensation silicone resin and the 
moisture-curable film-forming resin is about 2% by weight or more, 
preferably about 5 to about 95% by weight, of the former and about 98% by 
weight or less, preferably about 95 to about 5% by weight, of the latter, 
based on the combined amount of the two components. Use of below 2% by 
weight of the condensation silicone resin (i.e. above 98% by weight of the 
moisture-curable film-forming resin) is likely to increase the icing 
strength, hence undesirable. 
A proper moisture-curable film-forming resin for use in the invention is a 
resin having a silicon group represented by the formula 
##STR7## 
wherein R.sub.5 is a hydrocarbon group of 1 to 10 carbon atoms selected 
from an alkyl group, an aryl group and an aralkyl group, Z is a 
hydrolyzable group selected from a halogen atom, an alkoxy group, an 
acyloxy group, a phenoxy group and a thioalkoxy group and t is an integer 
of 1 to 3, the resin having per molecule at least one silicon group, 
preferably about 2 to about 1,200 silicon groups, attached to the 
hydrolyzable group or groups at the terminal or side chain. The presence 
of hydrolyzable group renders the resin moisture-curable. 
Silicon groups having hydrolyzable groups are introduced into the resin by 
(a) effecting a hydrosilyl-forming reaction between a resin having 
polymerizable carbon-carbon double bond and a hydrosilane compound 
represented by the formula 
##STR8## 
wherein R.sub.5, Z and t are as defined above in the presence of a VIII 
group transition metal catalyst, or (b) subjecting to radical 
copolymerization a polymerizable unsaturated compound and a silane 
compound represented by the formula 
##STR9## 
wherein R.sub.6 is an organic residue having polymerizable carbon-carbon 
double bond, and R.sub.5, Z and t are as defined above. 
Examples of hydrosilane compounds useful in the method (a) are 
methyldichlorosilane, trichlorosilane, phenyldichlorosilane and like 
halogenated hydrosilanes; methyldiethoxysilane, methyldimethoxysilane, 
phenyldimethoxysilane, trimethoxysilane, triethoxysilane and like 
alkoxyhydrosilanes; and methyldiacetoxyhydrosilane, phenyldiacetoxysilane, 
triacetoxysilane and like acyloxyhydrosilanes. 
Among these hydrosilane compounds, halogenated hydrosilane compounds, which 
are capable of easily reacting, give a resin which is preferably treated 
to introduce therein other hydrolyzable functional group replacing the 
halogen group because the resin containing a halogenated silicon group as 
hydrolyzable group is useful only for limited applications in view of the 
problems that the hydrogen chloride given off on exposure to air will emit 
an irritating odor and cause corrosion. 
Examples of resins having polymerizable carbon-carbon double bond which can 
be used in the method (a) are vinyl-type resins, polyester-type resins, 
polybutadiene-type resins, urethane-type resins and the like. 
Useful vinyl-type resins consist essentially of a copolymer of monomers 
such as methyl acrylate or methacrylate, ethyl acrylate or methacrylate, 
propyl acrylate or methacrylate, n-butyl acrylate or methacrylate, i-butyl 
acrylate or methacrylate, t-butyl acrylate or methacrylate, 2-ethylhexyl 
acrylate or methacrylate, cyclohexyl acrylate or methacrylate, n-octyl 
acrylate or methacrylate, lauryl acrylate or methacrylate, benzyl acrylate 
or methacrylate and like esters of acrylic or methacrylic acids; styrene, 
.alpha.-methylstyrene, vinyltoluene, p-chlorostyrene, p-t-butylstyrene and 
like vinyl aromatic compounds; acrylic or methacrylic acid, crotonic acid, 
fumaric acid, maleic anhydride or acid, itaconic anhydride or acid and 
like unsaturated carboxylic acids; glycidyl acrylate or methacrylate, 
vinyl glycidyl ether, allylglycidyl ether and like glycidyl-containing 
vinyl compounds; vinyl acetate, vinyl benzoate, "VEOVA" (trademark, 
product of Shell Chemical Co.) and like vinyl esters; acrylonitrile or 
methacrylonitrile and like cyano-containing monomers; 
N,N-dimethylaminoethyl acrylate or methacrylate, N,N-diethylaminoethyl 
acrylate or methacrylate and like N,N-dialkylaminoalkyl acrylate- or 
methacrylate-type tertiary amino-containing monomers; n-butyl vinyl ether, 
ethyl vinyl ether, methyl vinyl ether and like vinyl monomers; etc. 
Allyl groups as polymerizable carbon-carbon double bonds may be introduced 
into the copolymer by radical copolymerization using allyl acrylate or 
methacrylate and an azo-type polymerization initiator. Polymerizable 
double bonds may be also introduced into the copolymer by copolymerizing 
2-hydroxyethyl acrylate or methacrylate or like hydroxyl-containing 
polymerizable unsaturated compounds with the above monomer to react the 
hydroxyl group with an adduct of isophorone diisocyanate or tolylene 
diisocyanate with hydroxy acrylate or methacrylate (1/1 molar ratio); 
isocyanoethyl acrylate or methacrylate, 
m-isopropenyl-.alpha.,.alpha.'-dimethyl benzyl isocyanate or like 
isocyanate-containing polymerizable unsaturated compound. Optionally allyl 
groups may be introduced into the copolymer by incorporating isocyanate 
groups into the copolymer and reacting the isocyanate groups with the 
hydroxyl-containing polymerizable unsaturated compound. As a further 
option, polymerizable double bonds may be introduced into the copolymer 
utilizing the ability of functional groups to react with each other, e.g. 
reacting hydroxyl groups with carboxyl groups, reacting hydroxyl groups 
with acid anhydride groups, instead of reacting the isocyanate groups with 
the hydroxyl groups. 
The polyester-type resin for use in the method (a) predominantly contains a 
polyester resin prepared by condensing an organic acid component and an 
alcohol component which are commonly employed in preparation of polyester 
resins. Usually polybasic acids can be used as the organic acid component. 
Examples of useful polybasic acids are phthalic acid, isophthalic acid, 
terephthalic acid, tetrahydrophthalic acid, tetrahydroterephthalic acid, 
hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic 
acid, HET acid (chlorendic acid), trimellitic acid, hexahydrotrimellitic 
acid, pyromellitic acid, cyclohexanetetracarboxylic acid, 
methyltetrahydrophthalic acid, methylhexahydrophthalic acid, 
endometylenehexahydrophthalic acid, methylendomethylenetetrahydrophthalic 
acid, maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric 
acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, 
suberic acid, pimelic acid, dimer acid (dimer of tall oil fatty acid), 
tetrachlorophthalic acid, naphthalenedicarboxylic acid, 
4,4'-diphenylmethanedicarboxylic acid, 4,4'-dicarboxybiphenyl and the 
like, anhydrides thereof, dialkyl esters thereof, especially dimethyl 
esters thereof and the like. 
Dihydric and trihydric alcohols are usually used as the alcohol component. 
Examples of useful dihydric alcohols are ethylene glycol, propylene 
glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 
1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 
2,3-dimethyltrimethylene glycol, 3-methyl-1,5-pentane-diol, 
3-methyl-4,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 
1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,4-cyclohexanedimethanol, 
diethylene glycol, dipropylene glycol, triethylene glycol, neopentyl 
glycol, hydroxypivalic acid, neopentyl glycol ester, polyalkylene oxide, 
bishydroxyethylterephthalate, adduct of hydrogenated bisphenol A or 
bisphenol A with alkylene oxide and the like. Monoepoxy compounds such as 
Cardula E10 (trademark, product of Shell Chemical Co.), .alpha.-olefin 
epoxide, butylene oxide and the like can be also used as a kind of glycol. 
Examples of useful trihydric or polyhydric alcohols are glycerin, 
trimetylolpropane, trimethylolethane, diglycerin, pentaerythritol, 
dipentaerythritol, sorbitol and the like. 
Also usable are compounds having both carboxylic acid and hydroxyl group in 
the molecule. Examples of such compounds are dimethylolpropionic acid, 
pivalic acid, 12-hydroxystearic acid, ricinoleic acid, etc. Lactones such 
as .epsilon.-caprolactone, .gamma.-valerolactone, etc. are usable as well. 
The organic acid component and the alcohol component are partially replaced 
by natural or synthetic higher fatty acid, higher alcohol, 2-hydroxyethyl 
acrylate, 2-hydroxyethyl methacrylate, acrylic acid, methacrylic acid, 
benzoic acid, p-t-butyl benzoate and like monofunctional compounds or 
natural oil. 
Polymerizable double bonds may be introduced into the resin by using the 
organic acid component and alcohol component containing polymerizable 
unsaturated group. As another option, when the polyester resin prepared by 
condensing the organic acid component and the alcohol component contains 
hydroxyl group, introduction of polymerizable double bonds can be 
performed by reacting the hydroxyl group with the isocyanate-containing 
polymerizable unsaturated compound or by reacting the hydroxyl group with 
a polymerizable unsaturated compound having carboxyl group or acid 
anhydride group. On the other hand, when the polyester resin contains 
carboxyl group, the introduction of polymerizable double bond can be done 
by reacting carboxyl group with a polymerizable unsaturated compound 
having hydroxyl group in less than equivalent amount relative to the 
carboxyl group. 
In the method (a), a transition metal complex needs to be used as a 
catalyst in the reaction of the hydrosilane compound with the 
polymerizable double bond. Effectively usable as the transition metal 
complex catalyst is a VIII group transition metal complex compound 
selected from platinum, rhodium, cobalt, palladium and nickel. The 
reaction of the hydrosilane compound with the polymerizable double bond is 
conducted at a temperature of about 50 to about 150.degree. C. for about 1 
to about 10 hours. 
The amount of hydrosilane compound used in the reaction is preferably 0.5 
to 2 moles relative to the carbon-carbon double bond present in the 
vinyl-type resin. The amount of hydrosilane compound may exceed the range, 
but an excess thereof only results in recovery of the surplus as the 
unreacted hydrosilane. 
Examples of silane compounds useful in the method (b) are 
.gamma.-acryloyloxypropylmethyldimethoxysilane, 
.gamma.-acryloyloxypropyltrimethoxysilane, 
.gamma.-acryloyloxypropylmethyldichlorosilane, 
.gamma.-acryloyloxypropyltrichlorosilane, 
.gamma.-methacryloyloxypropylmethyldimethoxysilane, 
.gamma.-methaoryloyloxypropyltrimethoxysilane, 
##STR10## 
Vinyl monomers usable for synthesis of the copolymer which is the main 
component of the vinyl-type resin in the method (a) are also usable as the 
polymerizable unsaturated compound to be copolymerized with the silane 
compound in the method (b). 
The copolymer of vinyl monomer and silane compound can be synthesized by 
usual solution polymerization method using a vinyl monomer, silane 
compound, radical polymerization initiator and, when required, 
n-dodecylmercaptan, t-dodecylmercaptan or like chain transfer agent which 
assists to give a silylcontaining copolymer of suitable molecular weight. 
The polymerization is effected at a temperature of about 50 to about 
150.degree. C. with or without a solvent. Preferred solvents are 
unreactive ones such as ethers, hydrocarbons, esters of acetic acids, etc. 
While not specifically limited in molecular weight, the moisture-curable 
film-forming resin for use in the invention has a weight average molecular 
weight of preferably about 3,000 to about 200,000, more preferably about 
5,000 to about 100,000. 
The hydrolyzable group attached to the silicon atom in the resin prepared 
by the method (a) or (b) can be replaced by other hydrolyzable group by 
the conventional method. 
When required, in order to accelerate the condensation reaction between the 
reactive groups of the condensation silicone resin and the 
moisture-curable film-forming resin and to give a film of increased 
strength, the composition of the invention containing the condensation 
silicone resin and the moisture-curable film-forming resin may incorporate 
therein a dimethylsiloxane compound having alkoxysilyl groups at both 
terminals and represented by the formula 
##STR11## 
wherein R.sub.3 and R.sub.4 are the same or different and each represent a 
methyl group or an ethyl group, D and E are the same or different and each 
represent an oxygen atom, an ethylene group or a 1,3-propylene group, X is 
an integer of 3 to 30, m and r are the same or different and each 
represent an integer of 1 to 3, n is 3-m and S is 3-r. The film formed on 
an article from the composition comprising the condensation silicone resin 
and the moisture-curable film-forming resin has the moisture-curable 
film-forming resin present in the lower film portion (close to the 
substrate) and the condensation silicone resin present in the upper film 
portion (close to the atmosphere). The dimethylsiloxane of the formula 
(IV) incorporated in the composition serves to increase the bonding 
between these two resins and to enhance the ability to sustain the low 
icing strength for a long term. 
When required, the composition of the invention may further contain a 
silicone oil represented by the formula 
##STR12## 
wherein y is an integer of 1 to 20,000. The presence of the silicone oil 
of the formula (V) in the composition of the invention causes the 
hydrophobic polydimethylsiloxane chains and the alkyl chains in the 
condensation silicone resin to orien toward the atmosphere and readily 
prevents the orientation of highly polar alkoxysilyl groups toward the 
film surface (close to the atmosphere). 
Suitable proportions of condensation silicone resin, moisture-curable 
film-forming resin, dimethylsiloxane of the formula (IV) and silicone oil 
of the formula (V) in the composition of the invention are, based on the 
combined amount of the four components, about 2 to about 100% by weight, 
preferably about 5 to about 95% by weight, of the condensation silicone 
resin; about 98% by weight or less, preferably about 3 to about 95% by 
weight, of the moisture-curable film-forming resin; about 30% by weight or 
less, preferably about 20% by weight or less, of the dimethylsiloxane of 
the formula (IV); and about 30% by weight or less, preferably about 20% by 
weight or less, of the silicone oil of the formula (V). Below 2% by weight 
of the condensation silicone resin used or above 98% by weight of the 
moisture-curable film-forming resin used, an increase of icing strength 
tends to result. Above 30% by weight of the dimethylsiloxane of the 
formula (IV) used, a large quantity of the unreacted alkoxy group is 
likely to remain, tending to increase the icing strength. Above 30% by 
weight of the silicone oil of the formula (V) used, the composition 
applied to the substrate becomes less curable, tending to readily stain 
the film surface and to deteriorate the adhesion to the substrate. 
The composition of the invention may contain an organic solvent. A 
spray-type aerosol anti-icing agent which can be conveniently sprayed can 
be easily produced by filling an organic solvent and a propellant along 
with the composition into a container and hermetically closing the 
container. Useful organic solvents are any of those capable of dissolving 
or dispersing the composition of the invention such as xylene, toluene, 
methanol, ethanol, isopropanol, n-butanol, isobutanol, ethyl acetate, 
butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, hexane, 
heptane, isooctane, ethylene glycol monoethyl ether, ethylene glycol 
monobutyl ether, ethylene glycol monomethyl ether acetate and the like. 
Useful propellants include aerosol propellants commonly employed such as 
liquefied petroleum gas (LPG), liquefied carbon dioxide gas, flon gas, 
etc. The composition of the invention can be applied as well by brushing 
or by other spraying method than aerosol application. 
The composition of the invention contains the condensation silicone resin 
having the hydrophobic dimethylsiloxane chains predominantly present. The 
condensation silicone resin of the invention has a higher anti-icing 
effect than a silicone oil consisting of straight-chain dimethylsiloxane, 
and is excellent in anti-icing property, and high in adhesion to the 
substrate and in ability to sustain the anti-icing property due to the 
presence of alkoxy group and/or silanol group. Further the composition 
comprising the moisture-curable film-forming resin and optionally the 
compound of the formula (IV) as well as the condensation silicone resin 
gives a film with a higher strength and with a prolonged retention of 
anti-icing effect. 
The present invention will be described below in more detail with reference 
to the following examples in which the parts and the percentages are all 
by weight.

PREATION OF CONDENSATION SILICONE RESIN SOLUTIONS 
PREATION EXAMPLE 1 
______________________________________ 
##STR13## 90 parts 
wherein x is an integer of about 100 
on an average 
CH.sub.3 CH.sub.2 CH.sub.2 Si(OCH.sub.3).sub.3 
10 parts 
0.1N aqueous solution of 
4 parts 
hydrochloric acid 
Xylene 50 parts 
Methyl isobutyl ketone 
50 parts 
______________________________________ 
A mixture of the above components was reacted with stirring in a glass 
reactor at a temperature of 85.degree. C. for 3 hours. The reaction 
mixture was subjected to condensation at 120.degree. C. for 2 hours while 
removing the solvent, giving a solution A.sub.1 containing a condensation 
silicone resin with a weight average molecular weight of about 38,000. The 
solution had a solids content of 67%. 
PREATION EXAMPLE 2 
______________________________________ 
##STR14## 60 parts 
wherein x is an integer of about 10 
on an average 
##STR15## 40 parts 
wherein x is an integer of about 25 
on an average 
Tin octylate catalyst 0.5 part 
Toluene 100 parts 
______________________________________ 
A mixture of the above components was reacted with stirring in a glass 
reactor at 105.degree. C. for 2 hours. The reaction mixture was subjected 
to condensation for 2 hours while removing the solvent, giving a solution 
A.sub.2 containing a condensation silicone resin which was about 47,000 in 
weight average molecular weight. The solution had a solids content of 70%. 
PREATION EXAMPLE 3 
______________________________________ 
##STR16## 80 parts 
wherein x is an integer of about 50 
on an average 
CH.sub.3 Si(OCH.sub.3).sub.3 
20 parts 
0.1N aqueous solution of 
4 parts 
hydrochloric acid 
Xylene 50 parts 
Methyl isobutyl ketone 
50 parts 
______________________________________ 
A mixture of the above components was reacted with stirring in a glass 
reactor at 80.degree. C. for 3 hours. Subsequently the reaction mixture 
was subjected to condensation at 120.degree. C. for 2 hours while removing 
the solvent, giving a solution A.sub.3 containing a condensation silicone 
resin with a weight average molecular weight of about 34,000. the solution 
had a solids content of 62%. 
PREATION EXAMPLE 4 
______________________________________ 
##STR17## 35 parts 
wherein x is an integer of about 30 
on an average 
CH.sub.3 Si(OCH.sub.3).sub.3 
15 parts 
##STR18## 50 parts 
wherein x is an integer of about 25 
on an average 
Tin octylate catalyst 0.5 part 
Toluene 100 parts 
______________________________________ 
A mixture of the above components was reacted with stirring in a glass 
reactor at 105.degree. C. for 2 hours. The reaction mixture was subjected 
to condensation at the same temperature for 2 hours while removing the 
solvent, giving a solution A.sub.4 containing a condensation silicone 
resin with a weight average molecular weight of about 27,000. The solution 
had a solids content of 72%. 
PREATION EXAMPLE 5 
______________________________________ 
##STR19## 100 parts 
wherein x is an integer of about 10 
on an average 
0.1N aqueous solution of 
5.5 parts 
hydrochloric acid 
Xylene 50 parts 
Methyl isobutyl ketone 
50 parts 
______________________________________ 
A mixture of the above components was reacted with stirring in a glass 
reactor at 83.degree. C. for 3 hours. The reaction mixture was subjected 
to condensation at 120.degree. C. for 2 hours while removing the solvent, 
giving a solution A.sub.5 containing a condensation silicone resin about 
20,000 in weight average molecular weight. The solution had a solids 
content of 69%. 
PREATION OF MOISTURE-CURABLE FILM-FORMING RESIN SOLUTIONS 
PREATION EXAMPLE 6 
______________________________________ 
Methacryloyloxypropyl 30 parts 
trimethoxysilane 
n-Butyl acrylate 20 parts 
Methyl methacrylate 50 parts 
.alpha., .alpha.'-Azobisisobutyronitrile 
1 part 
______________________________________ 
A glass reactor was charged with 30 parts of xylene, 30 parts of butyl 
acetate and 15 parts of n-butyl alcohol and the mixture was heated to 
90.degree. C. To the mixture maintained at 90.degree. C. was added 
dropwise a mixture of the monomers and the catalyst as listed above by a 
dropping funnel over a period of 4 hours. After the addition, the mixture 
was heated to 110.degree. C. To the mixture maintained at 110.degree. C. 
was added dropwise a mixture of 10 parts of xylene, 10 parts of butyl 
acetate, 5 parts of n-butyl alcohol and 1 part of 
2,2'-azobis-2,4-dimethylvaleronitrile by a dropping funnel over a period 
of 30 minutes. After completion of the addition, the mixture was 
maintained at 110.degree. C. for 1 hour, giving a solution having a solids 
content of about 50% and containing an alkoxysilyl-containing acrylic 
resin with a weight average molecular weight of about 36,000. The resin 
contained about 130 silicon groups bonded to hydrolyzable groups per 
molecule. 
PREATON EXAMPLE 7 
______________________________________ 
Methacryloyloxypropyl 50 parts 
methyldimethoxysilane 
t-Butyl methacrylate 40 parts 
Lauryl acrylate 10 parts 
.alpha., .alpha.'-Azobisisobutyronitrile 
0.9 part 
______________________________________ 
A glass reactor was charged with 38 parts of xylene and 37 parts of n-butyl 
alcohol and the mixture was heated to 90.degree. C. To the mixture 
maintained at the same temperature was added dropwise a mixture of the 
monomers and the catalyst as listed above through a dropping funnel over a 
period of 4 hours. After the addition, the mixture was heated to 
110.degree. C. To the mixture maintained at 110.degree. C. was added 
dropwise a mixture of 12 parts of xylene, 13 parts of n-butyl alcohol and 
1 part of 2,2'-azobis-2,4-dimethylvaleronitrile over a period of 1 hour 
through a dropping funnel. After completion of the addition, the mixture 
was maintained at 110.degree. C. for 30 minutes, giving a solution having 
a solids content of about 50% and containing an alkoxysilyl-containing 
acrylic resin with a weight average molecular weight of about 42,000. The 
resin contained about 270 silicon groups bonded to hydrolyzable groups per 
molecule. 
PREATION EXAMPLE 8 
______________________________________ 
Allyl acrylate 25 parts 
Methyl methacrylate 30 parts 
n-Butyl acrylate 45 parts 
.alpha., .alpha.'-Azobisisobutyronitrile 
1 part 
______________________________________ 
A 40 parts quantity of xylene and 40 parts of butyl acetate were placed 
into a glass reactor and the mixture was heated to 90.degree. C. To the 
mixture maintained at the same temperature was added dropwise a mixture of 
the monomers and the catalyst as listed above through a dropping funnel 
over a period of 4 hours. After the addition, a mixture of 10 parts of 
xylene, 10 parts of butyl acetate and 1 part of 
2,2'-azobis-2,4-dimethylvaleronitrile was added dropwise to the reaction 
mixture maintained at 90.degree. C. over a period of 30 minutes. After 
completion of the addition, the mixture was maintained at 90.degree. C. 
for 1 hour, giving a solution containing an acrylic resin about 40,000 in 
weight average molecular weight. 
Subsequently, the resin solution was kept at 80.degree. C. To the solution 
was added dropwise a mixture of 0.4 part of platinum catalyst, 28 parts of 
trimethoxysilane and 28 parts of xylene over a 3-hour period. After the 
addition, the mixture was heated and maintained at 100.degree. C. at which 
0.1 part of platinum catalyst was added thereto, followed by 2 hours of 
reaction, giving a solution containing an alkoxysilyl group-containing 
acrylic resin and having a solids content of about 50%. The resin had 
about 210 silicon groups bonded to hydrolyzable groups in the molecule. 
PREATION EXAMPLE 9 
______________________________________ 
Phthalic anhydride 32.1 parts 
Trimethylolpropane 14.1 parts 
Pentaerythritol 14.5 parts 
Fatty acid of soybean oil 
46.2 parts 
______________________________________ 
A mixture of the above components was placed into a glass reactor and 
heated with stirring. The mixture was heated and maintained at 180.degree. 
C. for 1 hour to effect esterification. Then 5 parts of xylene was added 
and the mixture was heated to 230.degree. C. While refluxing xylene at 
230.degree. C., the reaction proceeded for about 4 hours and was 
terminated when the acid value (calculated as solids) reached 15. After 
the reaction mixture was cooled, xylene was added thereto, giving a resin 
solution having a solids content of 50%. The resin thus obtained was about 
23,000 in weight average molecular weight. 
Thereafter the obtained resin solution was maintained at 80.degree. C. and 
reacted with 27 parts of isocyanoethyl methacrylate until isocyanate group 
was substantially removed from the reaction system. To the reaction 
mixture maintained at 80.degree. C. was added dropwise a mixture of 21.1 
parts of trimethoxysilane, 0.15 part of platinum catalyst and 21 parts of 
xylene over a period of 3 hours. After the addition, the mixture was 
heated and maintained at 100.degree. C. and 0.05 part of a platinum 
catalyst was added. The mixture was reacted for 2 hours, giving an 
alkoxysilyl-containing polyester resin solution. The resin contained about 
120 silicon groups bonded to hydrolyzable groups per molecule. The 
solution had a solids content of 58%. 
EXAMPLE 1 
______________________________________ 
Condensation silicone resin 
20 parts 
solution A.sub.1 of Prep. Ex. 1 
Acrylic resin solution of 
2 parts 
Prep. Ex. 6 
Dimethylsiloxane 2 parts 
of the formula (IV) (Note 1) 
Silicone oil (Note 2) 
2.5 parts 
Isooctane 40 parts 
Ethanol 33.5 parts 
______________________________________ 
A container was charged with 100 parts of a mixture of the above components 
and 200 parts of LPG serving as a propellant and was hermetically sealed. 
The resulting composition was sprayed over an aluminum panel to form a 
film with a dry thickness of about 5 .mu.m. The coated panel was left to 
stand for 24 hours at room temperature for drying and the dried panel was 
used for determining icing-strength. Table 2 shows the result. 
##STR20## 
wherein x is an integer of about 5 on an average. 
##STR21## 
wherein x is an integer of about 8 on an average. 
EXAMPLES 2 TO 9 AND COMISON EXAMPLE 1 
Shear strength (kg/cm.sup.2) at an ice-substrate interface was determined 
in the same manner as in Example 1 with the exception of using the 
components as shown below in Table 1 in the listed amounts. Table 2 shows 
the results. 
TABLE 1 
__________________________________________________________________________ 
Example Comp. Ex. 
1 2 3 4 5 6 7 8 1 
__________________________________________________________________________ 
Condensation silicone 
resin solution 
Kind (Prep. Ex. No.) 
1 2 1 3 4 1 5 2 
Amount (part) 
20 19.5 
1.5 1.5 2.3 15 7.1 5 
Moisture-curable film- 
forming resin solution 
Kind (Prep. Ex. No.) 
6 7 7 7 6 8 9 
Amount (part) 
2 1.5 20 20 5 4.6 6 
Dimethylsiloxane 
of the formula (IV) 
Kind (Note No.) 
N1 N3 N1 N1 
Amount (part) 
2 1 1 1 
Silicone oil 
Kind (Note No.) 
N2 N4 N2 N2 N4 N4 N5 
Amount (part) 
2.5 2 1 1 0.7 2.5 15 
Solvent (part) 
Isooctane 40 40 40 40 20.2 
Ethanol 33.5 36.5 
36.5 
Heptane 35 35 13 
Butanol 20 40 35.3 
12 
Ethylene glycol mono- 
21 10 
methyl ether acetate 
Methyl isobutyl ketone 17 10 
Octane 85 85 
Propellant (part) 
LPG 200 200 200 200 200 200 150 200 
Carbon dioxide gas 200 50 
__________________________________________________________________________ 
The symbols N1 to N5 stand for (Note 1) to (Note 5), respectively. 
TABLE 2 
__________________________________________________________________________ 
Example Comp. Ex. 
1 2 3 4 5 6 7 8 1 
__________________________________________________________________________ 
Shear strength 
0.08 
0.18 
0.18 
0.15 
0.20 
0.05 
0.05 
0.24 
0.95 
(kg/cm.sup.2) (Note 6) 
Initial value 
Repeat test (Note 7) 
After 10 times 
0.21 
0.23 
0.27 
0.25 
0.23 
0.59 
0.41 
0.39 
3.20 
After 20 times 
0.24 
0.36 
0.28 
0.26 
0.25 
1.23 
0.49 
0.51 
4.73 
After 30 times 
0.38 
0.47 
0.30 
0.27 
0.28 
1.98 
0.53 
0.81 
-- 
After 40 times 
0.40 
0.69 
0.40 
0.38 
0.36 
-- 0.79 
0.87 
-- 
After 50 times 
0.43 
0.83 
0.48 
0.41 
0.45 
-- 0.93 
0.99 
-- 
Outdoor exposure test 
(Note 8) 
For 2 weeks 
0.45 
0.56 
0.45 
0.41 
0.35 
0.91 
0.38 
0.48 
5.75 
For 4 weeks 
0.57 
0.78 
0.55 
0.43 
0.58 
1.89 
0.48 
0.51 
-- 
For 8 weeks 
0.78 
0.91 
0.70 
0.59 
0.88 
-- 0.76 
0.87 
-- 
For 12 weeks 
0.93 
1.11 
0.78 
0.74 
0.99 
-- 1.12 
1.39 
-- 
__________________________________________________________________________ 
In Table 1, (Note 3), (Note 4) and (Note 5) denote the following. 
##STR22## 
wherein x is an integer of about 20 on an average. 
##STR23## 
wherein x is an integer of about 200 on an average. 
##STR24## 
wherein x is an integer of about 1,000 on an average, the oil having a 
viscosity of about 1,000 St. (at 25.degree. C.). 
The tests for checking the properties as designated (Note 6), (Note 7) and 
(Note 8) in Table 2 were carried out by the following methods. 
TEST METHODS 
Note 6 
Test method for determining the shear strength 
A stainless steel ring (5 cm.sup.2 in inner area) was placed on a test 
panel (an aluminum panel coated with the anti-icing coating composition 
for testing and then dried). The panel with the ring was introduced into a 
constant temperature bath for freezing test at -10.degree. C. and 
precooled for 90 minutes. A 2 ml quantity of deionized water and 
maintained at 5.degree. C. was poured into the inside of the ring to form 
ice on the coating surface on the panel which was then left to stand at 
-10.degree. C. for 2 hours. The panel with the ring attached thereto was 
connected to a load cell and force was applied to the ring by a 
powerdriven operating metal rod to measure the shear strength (unit: 
kg/cm.sup.2) required in separating the ice from the coating. 
Note 7 
Repeat test 
The test as described in (Note 6) was conducted repeatedly with the 
stainless steel ring placed in the same position on the test panel to 
measure the shear strength. Table 2 shows the results obtained each time 
when the test was repeated 10, 20, 30, 40 and 50 times, respectively. 
Note 8 
Test for determining the shear strength after outdoor exposure 
Test panels were inclined at an angle of 35.degree. and directed southward 
in Hiratsuka city, Kanagawa prefecture and subjected to outdoor exposure. 
The test as described in (Note 6) was conducted using four kinds of test 
panels each exposed to weather for 2, 4, 8 and 12 weeks, respectively. 
The shear strength was also measured on test panels not subjected to the 
test as described in (Note 6). 
Table 2 shows that ice was formed with low adhesion to the surface of the 
test panel coated with the anti-icing composition of the invention. The 
same effect was produced not only on the test panels coated with the 
anti-icing composition of the invention by aerosol application, but also 
on the test panels coated with the anti-icing composition of the invention 
free of a propellant by a brushing and air spray coating. 
Moreover, the coating compositions obtained in other Examples than Example 
6 and containing the moisturecurable film-forming resin sustained the 
anti-icing effect for a longer period of time than the composition of 
Example 6.