Antifoam composition and process with α-hydroxyamine derivatives
FIELD OF THE INVENTION 
     The present invention relates to antifoam compositions which are useful in decreasing the tendency of solutions, liquors and dispersions in a large number of industrial processes to form foam, and for breaking foam which has already formed. The invention includes methods for inhibiting the formation of foam and for breaking foam by the use of said antifoam compositions. The invention is particularly directed towards oil and latex paints of decreased tendency to form foam when applied to surfaces in conventional manners. 
     BACKGROUND OF THE INVENTION 
     It is known that dispersions of certain solid materials in organic fluids or in water are effective antifoaming agents which are useful for defoaming industrial waste water and for inhibiting the formation of foam in papermaking white water, in the production of cellulose, in the production of dispersions of natural and synthetic film-forming materials (e.g., oil and latex paints) and pigment and dye dispersions, in biological processes, particularly fermentations, and in the manufacture of food. The antifoam agents referred to are finely divided solids of waxlike consistency, for example, pentaerythritol fatty acid esters, fatty acid monoglycerides, fatty acid polyglycol esters and the like. (See US. Pat. No. 2,715,613. ) 
     OBJECTS OF THE INVENTION 
     An object of the present invention is the development of an antifoam composition of a liquid solution or dispersion containing from 1% to 25% by weight of an α-hydroxyamine derivative of the formula ##STR2## wherein A is a member selected from the group consisting of --NHCO-- and --NHCONH--, R 1  and R 2  are members selected from the group consisting of hydrogen and alkyl having from 1 to 22 carbon atoms, at least one of R 1  and R 2  being alkyl and the sum of the carbon atoms in R 1  + R 2  is from 8 to 22, and R 3  is a member having 8 to 22 carbon atoms selected from the group consisting of alkyl and hydroxyalkyl. 
     Another object of the present invention is the development of a process for the control of foam in a foamable liquid comprising adding to said foamable liquid an antifoam effective amount of an α-hydroxyamine derivative of the formula ##STR3## wherein A is a member selected from the group consisting of --NHCO-- and --NHCONH--, R 1  and R 2  are members selected from the group consisting of hydrogen and alkyl having from 1 to 22 carbon atoms, at least one of R 1  and R 2  being alkyl and the sum of carbon atoms in R 1  + R 2  is from 8 to 22, and R 3  is a member having 8 to 22 carbon atoms selected from the group consisting of alkyl and hydroxyalkyl. 
     These and other objects of the invention will become more apparent as the description thereof proceeds. 
     DESCRIPTION OF THE INVENTION 
     Accordingly the present invention provides a process for inhibiting foam formulation in a liquid which comprises adding to said liquid an α-hydroxyamine derivative of the general Formula I ##STR4## wherein A = --NHCO-- or -- NHCONH-- 1  R 1  and R 2  = H or alkyl radicals of the chain lengths C 1  --C 22 , the total of the carbon atoms in the radicals R 1  and R 2  being 8 to 22, 
     R 3  = an alkyl radical or hydroxyalkyl radical of the chain length C 8  --C 22  ; 
     as well as antifoam compositions of a liquid solution or dispersion containing from 1% to 25%, preferably from 5% to 15 %, by weight of an α-hydroxyamine derivatives of the general Formula I. The α-hydroxyamine derivatives of the general Formula I can be added advantageously to organic and aqueous compositions which have a tendency to foam under normal processing conditions (i.e., when agitated with inclusion of air). They are useful in breaking foam which has already formed. 
     In general, the invention also includes a solution or dispersion wherein the continuous phase is a liquid having a solidification point below 5° C and a boiling point above 80° C, containing therein in solution or finely-divided form from 1% to 25% by weight of an α-hydroxyamine derivative of the general Formula I. 
     More particularly, the present invention relates to an antifoam composition of a liquid solution or dispersion containing from 1% to 25% by weight of an α-hydroxyamine derivative of the formula ##STR5## wherein A is a member selected from the group consisting of --NHCO-- and --NHCONH--, R 1  and R 2  are members selected from the group consisting of hydrogen and alkyl having from 1 to 22 carbon atoms, at least one of R 1  and R 2  being alkyl and the sum of the carbon atoms in R 1  + R 2  is from 8 to 22, and R 3  is a member having 8 to 22 carbon atoms selected from the group consisting of alkyl and hydroxyalkyl; as well as a process for the control of foam in a foamable liquid comprising adding to said foamable liquid an antifoam effective amount of an α-hydroxyamine derivative of the formula ##STR6## wherein A is a member selected from the group consisting of --NHCO-- and --NHCONH--, R 1  and R 2  are members selected from the group consisting of hydrogen and alkyl having from 1 to 22 carbon atoms, at least one of R 1  and R 2  being alkyl and the sum of the carbon atoms in R 1  + R 2  is from 8 to 22, and R 3  is a member having 8 to 22 carbon atoms selected from the group consisting of alkyl and hydroxyalkyl. 
     The α-hydroxyamine derivatives of the general Formula I are manufactured in accordance with known methods. One proceeds from α- or non-terminal olefins of the chain lengths C 10  to C 24  such as are obtained by, for example, dehydrogenation of paraffin hydrocarbons or by oligomerization of ethylene, and reacts them with epoxidation agents such as peracetic acid to form the corresponding olefin epoxide. The corresponding α-hydroxyamine is obtained by further reaction with ammonia. 
     Further reaction to form the derivatives is effected either with higher alkanoic acids or their reactive derivatives, such as esters or halides, wherein an amide grouping is formed, or with higher alkane monoisocyanates with the formation of a urea grouping. Suitable carboxylic acids, carboxylic acid derivatives or isocyanates have straight chain or branched chain alkyl radicals or hydroxyalkyl radicals having 8 to 22 carbon atoms. Solid waxlike defoamers are produced when using higher straight chain carboxylic acids, hydroxy carboxylic acids or isocyanates, for example, compounds where R 3  has from 15 to 17 carbon atoms and is substantially straight-chained. such as palmitic acid, stearic acid, 12-hydroxystearic acid or the methyl, ethyl or glyceryl esters thereof or chlorides thereof, or dodecylisocyanate, tetradecylisocyanate or hexadecylisocyanate, while the reaction products with lower or branched chain carboxylic acids or isocyanates, for example, compounds where R 3  has from 12 to 15 carbon atoms and is a branched-chain alkyl, such as isopalmitic acid, isotridecanoic acid or first distillate fatty acids of the chain lengths C 8  --C 10  and octylisocyanate or decylisocyanate, are semi-solid or liquid. 
     Preferably, the defoamers are used in the form of a fine-particulate dispersion in an organic or aqueous liquid. Waxlike defoamers having a melting point in excess of 60° C are particularly suitable for this purpose, although semi-solid or liquid products can be used in the same manner. In addition to water, organic substances, which are liquid at normal temperature and which have an adequately low solidification point or melting point of less than 5° C, are primarily suitable as the liquid phase. A relatively high viscosity is also advantageous, since this contributes to the stabilization of the dispersion. The liquid phase itself can have a defoaming effect or act only as a carrier for the defoamer. 
     Suitable liquids for the purpose are materials which have boiling points above the melting point of the α-hydroxyamine derivative selected. These include esters of aliphatic acids (which are branched or unsaturated) having 8 to 18 carbon atoms with monovalent or polyvalent alcohols, such as the glycol diester or glycerine triester of oleic acid and oleic oleate, etc., and also branched chain saturated or unsaturated liquid fatty acids and fatty alcohols having 8 to 18 carbon atoms, for example, isotridecyl alcohol and oleyl alcohol, and terpene hydrocarbons, for example, pine oil, oil of turpentine and the like. However, preferable to all of these are mineral oils which have boiling points in excess of 140° C. 
     It is advantageous to use as the liquid (i.e., continuous) phase non-ionic hydrophobic (i.e., water-insoluble) organic fluids which at elevated temperatures possess a good solvent power for the defoamer but which are substantial non-solvents for these materials at room temperature so that they precipitate the α-hydroxyamine derivatives in finely divided form upon cooling. Liquids of this type render it possible to manufacture the defoaming dispersions in an economical manner by heating the solvent and the antifoam agents together and then rapidly cooling the resulting solution with intensive agitation, whereby an extremely fine particulate and stable dispersion is obtained. Alternatively, however, it is possible to manufacture the dispersion by stirring the waxy antifoam agents in highly particulate form into the liquid phase at room temperature, or by emulsifying a defoamer in liquid state. The dispersions preferably contain approximately 5% to 15% by weight of the antifoam agent, but may contain a larger or smaller proportion, if desired, from 1% to 25% by weight, as long as the dispersion is of fluid viscosity at normal temperature (20° C to 40° C). 
     Semi-solid or liquid defoamers, such as are obtained by amidification of an α-hydroxyamine with branched fatty acids, such as isotridecanoic acid, or relatively short-chain fatty acids, such as first distillate fatty acids, or such as are obtained by reaction with short-chain isocyanates of the chain lengths C 8  -C 10 , can be added in a dissolved form or as such to the liquids to be defoamed. Suitable solvents are water-soluble alcohols, polyglycols or dioxane. 
     When a dispersion of the solid α-hydroxyamine derivative in a liquid is employed, the solid particles should be sufficiently small so that the dispersion is substantially self-sustaining at room temperature, i.e., so that the particles do not noticeably cream or settle out during normal storage (two weeks at 20° C). Preferably, the particles are of such size that at room temperature a 1% by weight dispersion of the antifoam in organic liquid or in water possesses an opalescent haze which indicates that the particles are of colloidal dimensions and which exhibits the Tyndall effect. Dispersions of this extreme and very desirable particle size can be attained by passing the dispersion through a colloid mill or homogenizer, and this is specially advantageous when the dispersion medium is water. 
     The defoamers in accordance with the invention have an excellent defoaming power and can be used with unexpectedly satisfactory results in a number of industrial processes, and also in cases in which the controlling of foam normally presents great difficulties. However, for use in particularly difficult or special fields of application, it can be advantageous to add to the defoamers other known substances having a defoaming action, such as silicone oils, fats, waxes, fatty acids, adducts of ethylene oxide and/or propylene oxide to fatty alcohols, alkylphenols or fatty acids and the like. The defoaming action which can be obtained with combinations of this type is frequently greater than that obtainable with the individual components. 
     The defoamers can be added directly to the liquids which tend to form foam, preferably in the form of dispersions thereof in organic or aqueous liquids, such as polymeric dispersions, such as polyacrylate, polystyrene, polybutadiene, or polyvinylacetate dispersions. Accordingly, they can also be directly incorporated in aqueous paper-coating compositions or dispersion paints (latex paints). Another possibility of use resides in adding the defoamer at the location where the foam is formed, for example, during the manufacture of paper and cellulose or during the defoaming of waste water. In this case, the foam is controlled by sprinkling or spraying the defoamer in the working range of agitators or pumps, at overflows and the like. The defoamers can also be used in the same manner to control troublesome foam in the food industry, for example, in the production of sugar and yeast, and in fermentation processes. The quantities used depend upon the nature of the relevant substrate and its tendency to foam. Consequently, the metering of the defoamer, particularly during sprinkling or spraying, is adapted to the effect to be obtained. When adding the defoamers to foaming solutions or incorporating them in dyestuff dispersions or polymeric dispersions and the like, the quantities of defoamer required are approximately 0.5 to 10 gm/liter. A suitable amount can be readily determined by trial. 
     The following examples are illustrative of the invention without being limitative in any respect. 
    
    
     EXAMPLES 
     Production of the α-hydroxyamine derivative defoamers is shown by Examples 1 to 4. 
     EXAMPLE 1 
     301.0 gm of 12-hydroxystearic acid were placed in a round-bottomed flask provided with an agitator, thermometer and condenser; 274.5 gm of a non-terminal α-hydroxyamine were added at 90° to 95° C under agitation, and the reaction mixture was subsequently heated to 200° C while being purged with nitrogen and was agitated at this temperature until the acid number had dropped to 5. The reaction mixture was then cooled. The slightly yellowish α-hydroxycarboxylic acid amide obtained had a melting range of from 80° C to 90° C and corresponded to the general Formula I, given in the description, with the following carbon chain distribution: 
     (R 1  + R 2 ) = approximately 25% C 13   
     approximately 30% C 14   
     approximately 30% C 15   
     approximately 15% C 16   
     The yield was 553 grams. EXAMPLE 2 
     In the same manner as described in Example 1, 273 gm of technical stearic acid were reacted with 274.5 gm of the same α-hydroxyamine. 525 gm of a slightly yellowish product having a melting range of 55° C to 65° C were obtained. 
     EXAMPLE 3 
     283 gm of hardened beef tallow were melted in a round-bottomed flask provided with an agitator, a thermometer and a reflux condenser, and 223 gm of an α-hydroxyamine corresponding to Example 1 were added. The mixture was heated to 200° C while being purged with nitrogen and was agitated for two hours at this temperature. Approximately 505 gm of a light brown, waxlike defoamer were obtained after cooling. 
     EXAMPLE 4 
     111.5 gm of an α-hydroxyamine corresponding to Example 1 were heated to 80° C in an agitated flask while being purged with nitrogen. 148 gm of stearylisocyanate were added drop by drop at this temperature within 45 to 60 minutes. After further agitation for 30 minutes at 90° C to 95° C, the mixture was cooled. 259 gm of a light yellow waxlike defoamer were obtained and solidified at approximately 40° C. 
     Production of defoamer dispersions is shown by Examples 5 to 8. 
     EXAMPLE 5 
     895 parts by weight (PW) of mineral oil (D 15 ° =  0.901, η 20 =  32 cSt, solidification point -15° C) were heated to approximately 90° C in a stirring mechanism having a high-speed agitator. 70 PW of the defoamer in accordance with Example 1, 30 PW of a polyalkylene glycol (57% propylene oxide, 43% ethylene oxide, molar weight 3500) esterified with stearic acid, and 5.0 PW of aluminum stearate were stirred into the heated oil until an homogeneous solution was produced. The mixture was then cooled to normal temperature. 
     EXAMPLE 6 
     A defoamer dispersion was produced in the same manner with the defoamer described in Example 2. 
     EXAMPLE 7 
     A defoamer dispersion was produced in the same manner with the condensation product described in Example 3. 
     EXAMPLE 8 
     A defoamer dispersion was produced in the same manner with the condensation product described in Example 4. 
     EXAMPLE 9 
     Defoaming a Dispersion Paint 
     A dispersion paint was manufactured in accordance with the following formulation with the use of polyacrylate dispersions and the defoamer dispersion of Examples 5 to 8: 
     
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                    Parts by                                              
                    Weight                                                
______________________________________                                    
Propyleneglycol-1,2   65.2                                                
Aqueous sodium polyacrylate                                               
solution, 25%         14.0                                                
Antifoaming agent in accordance                                           
with one of Examples 5 to 8                                               
                      4.7                                                 
Water                 18.6                                                
Titanium oxide        256.0                                               
Water                 46.6                                                
Aqueous polyacrylate dispersion,                                          
46% to 47% η  = 1000 cP.sub.25°                                
                      509.0                                               
Tributylphosphate     17.1                                                
Preservative          2.8                                                 
Antifoaming agent in accordance                                           
with one of Examples 5 to 8                                               
                      4.7                                                 
Ammonia (25%)         2.0                                                 
propyleneglycol-1,2   28.0                                                
Ammonium polyacrylate                                                     
solution, 22%         9.3                                                 
Water                 22.0                                                
                      1,000.0   PW                                        
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     The constituents listed above were mixed in a Dissolver in the given sequence, with the exception of the preservative which had previously been dissolved in tributylphosphate, and the 22% ammonium polyacrylate solution which had previously been diluted with water. 
     Testing the Foaming Behavior 
     80 PW of the paint were mixed with 20 PW of water and agitated in a Dissolver (diameter of the dispersion disc = 40 mm) for one minute at 2,000 r.p.m. and one minute at 3,000 r.p.m. 50 ml of the paint were subsequently weighed out. The higher the weight of the sample, the lower is the content of air and, consequently, the better the action of the defoamer used. 
     The paints were further tested in an application test. The dispersion paint, diluted with water in the ratio 80:20, was agitated in a Dissolver for one minute at 2,000 r.p.m. 
     The smooth sides of pieces of hard fiberboard having the dimensions 20 × 30 × 0.4 cm were sealed by applying a plastics lacquer dispersion, diluted in the ratio 1:1, by means of a brush. 60 to 70 gm of the paint agitated in the Dissolver were then applied to the piece of hard fiberboard and were uniformly distributed by means of a foam roller such that 15 gm of wet paint, corresponding to 250 gm/m 2 , remained. 
     The foam roller had a width of 6 cm and a diameter of 7 cm. It was made from open-pore polyurethane foam. When using a roller of this type, air is additionally incorporated in the coating in the same manner which occurs, to a lesser extent, when applying the coating by means of a brush. 
     In the evaluation of the coating film in the following Table, 1 indicates that the film of paint has a very large number of flaws caused by air bubbles. The value 6 indicates that the coating has dried completely without air bubbles. 
     
         ______________________________________                                    
                        Value in                                          
             Weight of  Application                                       
             50 ml in gm                                                  
                        Test                                              
______________________________________                                    
Blank value (paint                                                        
without defoamer)                                                         
               43.2         1                                             
Paint with defoamer,                                                      
Example 5      59.0         4 to 5                                        
Paint with defoamer,                                                      
Example 6      58.0         4                                             
Paint with defoamer,                                                      
Example 7      51.3         4                                             
Paint with defoamer,                                                      
Example 8      51.0         4                                             
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     EXAMPLE 10 
     Testing the Foaming Behavior of Molasses Solutions 
     The effect of defoamers on solutions occurring in the sugar and yeast industry can be tested in the laboratory in the following manner. 
     A two-liter measuring cylinder is filled with 500 ml of molasses diluted with water in the ratio 1:4. The solution is drawn from the bottom of the measuring cylinder with a glass tube by means of a laboratory hose pump. The liquid is returned by way of a second tube whose bottom end is located on a level with the top edge of the measuring cylinder. The liquid is circulated at a speed of four liters per minute and returns into the measuring cylinder. In order to maintain a constant temperature, the measuring cylinder is located in a water bath adjusted to 25° C. 
     A substantially constant level of foam is established in the measuring cylinder after the pump has been running for a short period of time. The total volume of liquid and foam which has been read off, reduced by the volume of liquid initially measured, is given as the measured value. After standardizing the blank value relative to the quantity of molasses, 0.01% by weight of defoamer is added from a micropipette, and the fresh level of foam now established is measured at varying intervals of time. 
     Liquid α-hydroxycarboxylic acid amides were obtained by reacting the α-hydroxyamine of Example 1 with isotridecanoic acid (A) or with isopalmitic acid (B) in the molar ratio 1:1 in accordance with Example 1, and were used for the defoaming of molasses solutions. 
     The following results were obtained: 
     
         ______________________________________                                    
Blank                                                                     
Value   0.5    1      2    3    5    10   20   30 min.                    
______________________________________                                    
A   1,500   120    100  100  120  140  500  1,360                         
                                                 1,480                    
                                                 ml                       
B   1,500   280    140  140  160  400  820  1,400                         
                                                 1,480                    
                                                 ml                       
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     It can thus be seen that a substantial defoaming effect was observed which had a practically instantaneous onset and lasted for five to ten minutes. 
     The preceding specific embodiments are illustrative of the practice of the invention. It is to be understood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the invention or the scope of the appended claims.