Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2000-08-11
2003-02-18
Metzmaier, Daniel S. (Department: 1712)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C516S118000, C516S120000, C516S121000, C510S347000, C510S349000, C510S361000, C510S377000, C510S507000
Reexamination Certificate
active
06521587
ABSTRACT:
FIELD OF THE INVENTION
This invention is concerned with silicone-based foam control agents, particularly for use in aqueous compositions, preferably detergent compositions.
In many aqueous systems which are used e.g. in food processes, textile dying, paper production, sewage treatment and cleaning applications, surface active agents are present either as an unwanted ingredient or as deliberately introduced materials to achieve a certain function. Due to the presence of these surface active agents foam is often generated. In certain applications, such as in dish washing by hand, this is a welcome effect but in other applications foam generation can lead to unsatisfactory results. This is for example the case in the dyeing of textiles or in the manufacture of paper. In other applications, for example the use of detergent compositions for domestic laundering, the production of foam needs to be controlled rather than avoided. It is important to keep the foam formation to an acceptable level when laundering is performed in automatic washing machines, especially front loading machines. Excessive foam would cause overflow of the washing liquor onto the floor as well as reduction in the efficiency of the laundering operation itself.
BACKGROUND OF THE INVENTION
Silicone-based foam control agents are known and have been incorporated into for example heavy duty detergent powders and liquids for use in automatic washing machines. Silicone foam control agents are regarded as very effective in this application as they can be added in very small quantities and are not affected by e.g. the hardness of water, while traditional foam control compositions, such as soaps, require a certain water hardness for their effectiveness. However, they are usually not cheap, and there is a need to find ways to cheapen such formulations without compromising the cost-efficiency of the foam control agents.
In addition, the detergent industry is constantly going through an evolution where, due to environmental concerns, energy conservation efforts, machine design changes, water conservation and changing laundering habits there is a move towards the use of detergent compositions which will perform to a higher efficiency than hitherto. There is a need to control foam from e.g. increased surfactant levels in the detergent compositions, use of surfactants which have a higher foam profile than traditional surfactants and changing laundering conditions. Since silicone foam control agents do not directly contribute to the cleaning power of a detergent composition it is desirable to keep the addition level of such foam control agents to a minimum. There has therefore arisen a need to develop improved foam control agents for incorporation into detergent compositions.
Silicone foam control agents are mostly based on organopolysiloxane materials, which may be linear or branched, and which may contain a variety of silicon-bonded substituents. EP 217501 describes a foam control agent wherein a liquid siloxane component is obtained by mixing 100 parts by weight of a polydiorganosiloxane having triorganosiloxane end-groups, 10 to 125 parts of a polydiorganosiloxane having at least one terminal silanol group and at least 40 silicon atoms and 0.5 to 10 parts of an organopolysiloxane resin comprising monofunctional and tetrafunctional siloxane units in a ratio of from 0.5:1 to 1.2:1, and having at least one silanol group per molecule, and there-after heating the mixture. The specification describes the need to control the amount of resin used in order to retain a liquid polymer, avoiding a gel structure. This indicates that some branching occurs in the siloxane component of the foam control agent.
JP-A-56-139107 describes a self-emulsifying antifoaming agent comprising an organopolysiloxane oxyalkylene copolymer of the formula
where G is an oxyalkylene group; Y is —CH2CHR″—R5-D or —CH2CHR″COOR″, where R″ is H or alkyl, R5 is divalent hydrocarbon, for example ethylene, propylene, butylene, phenylene or phenethylene, and D is H or OH; a, b and c are each 0,1,2 or 3 and a+b+c=3.
GB 2257709 describes a foam control agent which is particularly useful when incorporated in detergent compositions where a high level of high foaming surfactants is present, and comprises a branched polydiorganosiloxane which is prepared through hydrosilylation.
GB 1224026 describes an antifoaming agent which is composed of 10 parts by weight of certain water-insoluble organic liquids and from 0.1 to 5.0 parts by weight of an organopolysiloxane which is compatible in the organic liquid and consists essentially of monovalent and tetravalent siloxane units. U.S. Pat. No. 3,666,681 describes an antifoaming agent for aqueous systems consisting essentially of a mixture of 100 parts by weight of certain water-insoluble organic liquids, from 0.5 to 10.0 parts by weight of an organopolysiloxane, which may be a fluid or a resinous compound, and from 0.5 to 10.0 parts by weight of a filler which is selected from finely divided silica and methylsilsesquioxane gel, and from 0.002 to 5.0 parts by weight of a compound which is selected from ammonia, a disilazane and an alkali or alkaline earth metal hydroxide.
SUMMARY OF THE INVENTION
There is still a need to provide more efficient foam control agents. We have now found that if organopolysiloxane materials with certain aromatic substituents are combined with water-insoluble organic liquids in the presence of certain organosilicon resins and fillers, a more efficient foam control is obtained.
A foam control agent according to the invention comprises (A) an organopolysiloxane material having at least one silicon-bonded substituent of the formula X—Ph, wherein X denotes a divalent aliphatic hydrocarbon group and Ph denotes an aromatic group, (B) a water-insoluble organic fluid, (C) an organosilicon resin and (D) a hydrophobic filler.
DETAILED DESCRIPTION OF THE INVENTION
The organopolysiloxane material (A) is preferably a fluid and is preferably a polydiorganosiloxane. The aromatic group Ph can be unsubstituted or substituted. (A) preferably comprises diorganosiloxane units of the formula
where Y is an alkyl group having 1 to 4 carbon atoms, preferably methyl. These diorganosiloxane units containing a —X—Ph group may comprise substantially all or a majority of the diorganosiloxane units in (A), but preferably comprise up to 50%, most preferably 5 to 40%, of the diorganosiloxane units in (A). The group X is preferably a divalent alkylene group having from 2 to 10 carbon atoms, most preferably 2 to 4 carbon atoms, but can alternatively contain an ether linkage between two alkylene groups or between an alkylene group and —Ph, or can contain an ester linkage. Ph is preferably a moiety containing at least one aromatic ring —C
6
R
5
, wherein each R independently denotes hydrogen, halogen, hydroxyl, an alkoxy group having 1 to 6 carbon atoms or a monovalent hydrocarbon group having 1 to 12 carbon atoms, or wherein two or more R groups together represent a divalent hydrocarbon group. Ph is most preferably a phenyl group, but may be substituted for example by one or more methyl, methoxy, hydroxy or chloro group, or two substituents R may together form a divalent alkylene group, or may together form an aromatic ring, resulting in conjunction with the Ph group in e.g. a naphthalene group. A particularly preferred X—Ph group is 2-phenylpropyl —CH
2
—CH(CH
3
)—C
6
H
5
. Alternatively —Ph can be a heterocyclic group of aromatic character such as thiophene, pyridine or quinoxaline.
The polydiorganosiloxane (A) also preferably comprises at least 50% diorganosiloxane units of the formula
where Y′ is an aliphatic hydrocarbon group having 1 to 24 carbon atoms, preferably 1 to 6 carbon atoms, for example ethyl, methyl, propyl, isobutyl, hexyl, vinyl or lauryl, or a cycloalkyl group such as cyclohexylethyl. Mixtures of alkyl groups Y′ can be used. Other groups may be present, for example haloalkyl groups such as chloropropyl, acyloxyalkyl or alkoxyalkyl groups or aromatic groups such as
L'Hostis Jacqueline
Renauld Franck
Sawicki George
Dow Corning S.A.
Metzmaier Daniel S.
Reising Ethington, Barnes, Kisselle, Learman & McCulloch, P.C.
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