Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2001-01-08
2002-04-09
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S347000
Reexamination Certificate
active
06369022
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a foam control agent for detergent compositions, particularly a foam control agent comprising a silicone antifoam.
BACKGROUND OF THE INVENTION
Detergent compositions used, for example in washing applications, contain surfactants which promote the production of foam during a washing process. The amount of foam produced when detergent compositions are agitated, as found during a washing process, can be excessive which can have detrimental effect upon the cleaning efficiency of the detergent composition. It is therefore desirable to control the amount of foam generated and generally foam control agents are added to the detergent composition for this purpose.
Silicone antifoams are known in the art, for example in U.S. Pat. No. 5,968,889 and EP 709451. U.S. Pat. No. 5,668,095 describes a suds suppressing system for detergent compositions which comprises a mixture of a silicone oil with a 2-alkyl alcanol. U.S. Pat. No. 4,806,266 describes a particulate foam control agent in finely divided form for inclusion in a detergent composition in powder form, the agent comprising 1 part by weight of a silicone antifoam and not less than 1 part by weight of an organic material which is a fatty acid or a fatty alcohol having a carbon chain containing from 12 to 20 carbon atoms and a melting point in the range 45 to 80° C. and being insoluble in water. U.S. Pat. No. 5,238,596 describes particulate foam control agents for powder detergents comprising silicone antifoam with at least 30% by weight water insoluble 12-20C fatty acid or fatty alcohol and melting point in the range 45-80° C. or a monoester of glycerol and a fatty acid having a melting point in the range 50-85° C., and a native starch carrier material. U.S. Pat. No. 4,824,593 describes an antifoam agent in the form of a polysiloxane in a fatty acid matrix.
U.S. Pat. No. 3,329,625 describes a defoaming cleaning cake, for use in a floor cleaning device, comprising a wax-like material of melting point 40-100° C., a polyalkylene oxide emulsifier and suspended particles of polydimethylsiloxane.
There is a trend in the detergents industry towards compositions containing more high foaming surfactants. There is therefore a need to provide an improved foam control agent suitable for use in detergent compositions which avoids the need for higher concentrations of silicone antifoams with the high foaming surfactants.
SUMMARY OF THE INVENTION
We have found according to the invention that the use of unsaturated alcohols in combination with silicone antifoams enhances the ability of silicone antifoams to control foam formation.
According to the invention there is provided a foam control agent comprising a silicone antifoam and an olefinically unsaturated alcohol.
DETAILED DESCRIPTION OF THE INVENTION
The silicone used in the foam control agent of the present invention is generally a liquid organopolysiloxane polymer and can be any of those suggested for use in silicone antifoams, for example as described in EP 578424. The polymers can be linear or branched having a structure according to the general formula (I).
In formula (I), R″ denotes a monovalent hydrocarbon group having from 1 to 35 carbon atoms, preferably 1 to 8 carbon atoms. The groups R″ may be the same or different. R
1
denotes a group R″, a hydroxyl group or a group according to the general formula (II).
wherein R2 denotes a divalent hydrocarbon, hydrocarbonoxy, siloxane group or oxygen and Y denotes a group R″ or a hydroxyl group, a, b and c have a value of 0 or an integer, provided at least one of a and b is an integer and the total of a+b+c has a value such that the viscosity of the organopolysiloxane polymer at 25° C. is at least 50 mm
2
/s, preferably at least 500 mm
2
/s. In the case where the organopolysiloxane polymers are linear, R1 denotes R″ or a hydroxyl group. It is preferred for the linear organopolysiloxanes that Y denotes a group R″ and that b=0.
Preferred polymers include those wherein at least 60 or even 80% of all R″ groups denote an alkyl group having from 1 to 4 carbon atoms, most preferably methyl. The organopolysiloxane may be a trimethylsiloxy end-blocked polydimethylsiloxane, a polydiethylsiloxane or a methylphenylpolysiloxane, or may contain alkyl groups having 9 to 35 carbon atoms as described in U.S. Pat. No. 5,486,306. The organopolysiloxane can alternatively comprise an organopolysiloxane material having at least one silicon-bonded substituent of the formula X—Ph, wherein X denotes a divalent aliphatic organic group bonded to silicon through a carbon atom and Ph denotes an aromatic group as described in U.S. application Ser. No. 09/636,799, for example 2-phenylethyl or 2-phenylpropyl groups formed by reaction of styrene or alpha-methylstyrene with a Si—H group. The preferred viscosity of the organopolysiloxanes is from 500 to 100,000 mm
2
/s and more preferably 1000 to 60,000 mm
2
/s at 25° C.
Preferably the liquid organopolysiloxanes are branched or higher viscosity siloxanes (i.e. above 12,500 mm
2
/s at 25° C.). In the case where the organopolysiloxanes have branching in the siloxane chain, the polymers preferably have a structure according to Formula (I), wherein b has a value of at least 1 and R2 is preferably a divalent siloxane group or an oxygen atom. Preferred siloxane groups R2 can be formed by reaction of a siloxane resin with a polydiorganosiloxane polymer as described in U.S. Pat. No. 4,396,524. Branched siloxanes and methods of making them are described in a number of patent specifications, e.g. EP217501 and U.S. Pat. No. 5,055,229.
The silicone antifoam can additionally comprise a filler. Suitable fillers are described in many publications, for example U.S. Pat. No. 4,072,621. The fillers are generally finely divided particulate materials and include silica, fumed TiO2, Al2O3, zinc oxide, magnesium oxide, silicone resins, for example, alkylated silicone resins, salts of aliphatic carboxylic acids, reaction products of isocyanates with certain materials e.g. cyclohexylamine, alkyl amides, for example, ethylene or methylene bis stearamide.
The most preferred fillers are silica particles with a surface area of at least 50 m
2
/g as measured by BET. Suitable silica particles may be made according to any of the standard manufacturing techniques, for example, thermal decomposition of a silicon halide, decomposition and precipitation of a metal salt of silicic acid, e.g. sodium silicate and a gel formation method. Suitable silicas for use in the silicone antifoams include fumed silica, precipitated silica and gel formation silica. The average particle size of the fillers preferably range from 0.1 to 20 micrometers, more preferably 0.25 to 10 micrometers and most preferably 0.5 to 5 micrometers.
Preferably the surface of the filler is rendered hydrophobic, and this can be effected by treatment of the filler particles with treating agents, e.g. reactive silanes or siloxanes, for example, dimethyldichlorosilane, trimethylchlorosilane, hexamethyldisilazane, hydroxyl end-blocked and methyl end-blocked polydimethylsiloxanes, siloxane resins, fatty acids or a mixture of one or more of these. Fillers which have already been treated with such compounds are commercially available from many companies, e.g. from Degussa. The surface of the filler may be rendered hydrophobic prior to the addition of the filler to the organopolysiloxane. Alternatively the filler surface may be rendered hydrophobic in situ, i.e. after the filler has been dispersed in the liquid organopolysiloxane component. This may be effected by adding to the liquid organopolysiloxane prior to, during or after the dispersion of the filler therein, the appropriate amount of treating agent of the kind described above either in the presence of a catalyst and/or heating the mixture to a temperature above 40° C. The filler is preferably present at 1 to 20 or 25% by weight of the antifoam, most preferably from 2 to 8%.
The silicone antifoam may additionally contain a siloxane resin, for examp
Hoogland Jan
Sawicki George
Dow Corning S.A.
Duane Morris LLP
Gupta Yogendra N.
Petruncio John M
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