A SURFACTANT CONTAINING BINARY, WATER DISPLACEMENT COMPOSITION

Abstract: Article drying compositions which effectively remove water from the surface of non-absorbent articles to be dried. The solvents used to formulate the additive modified compositions are azeotropic binary mixtures, comprised of isobutanol and trichlorotrifluoroethane; and n-butanol and trichlorotrifluoroethane. The non-volatile additive, dissolved in the binary systems comprises a phosphate ester free acid type. These additives characterized as complex phosphate ester-free acid surfactants of the ethylene oxide type, which are commercially available, are preferred.

Description: A-SURFACTANT CONTAINING BINARY, WATER DISPLACEMENT COMPOSITION The invention relates to water removal composi¬ tion. More particularly, the invention relates to improved compositions for drying water wet articles in which the residue left on the dried article using the water removal composition is substantially reduced. The wettability is enhanced through the presence of iso-butanol or n-butanol as one of the components of the azeotropic mixtures used in these formulations. BACKGROUND OF THE INVENTION Various drying compositions are known in the prior art. These compositions contain various kinds and various amounts of surfactants and other additives. Specifically, the concentration of surfactants added to chlorocarbon and chlorofluorocarbon solvents, such as, methylene chloride or 1,1,2-trichloro-l,2,2-trifluoro- ethane typically used in amounts of 500 pp or greater, such as in U.S. Patent Nos. 3,386,181; 4,401,584 and 4,438,026 are known. Such levels of surfactant leave substantial residue on dried parts from the drying solvent and require relatively long rinse times. Moreover, the inclusion in the drying composition of such relatively large amounts of surfactants hinders phase separation in that water becomes more miscible and hence more difficult to remove. It is thus apparent that a need exists for an improved drying composition characterised as an azeotrope which can function at a low additive level and maintain higher solvency power and enhanced wettability. SUMMARY OF THE INVENTION It is a primary object of the invention to provide a water removal composition that functions at a low additive level and enhanced wettability. It is a more particular object of the invention to provide an azeotropic drying composition of 1, 1, 2-trichloro-l, 2, 2- trifluoroethane and n-butanol or isobutanol which leave minimal residue on articles dried with these compositions and which because of the low solubility of water therein permits a more complete phase separation. The presence of n-butanol or isobutanol is the base solvent contributes to water removal by improving 5 solvent wettability in a manner similar to surfactant, but without increasing non-volatile residue; hence not contributing to rinse sump contamination or process time. This is an advantage over the prior art. The azeotropic nature of the volatile components of the U-- composition of the invention provides increased wettability to both liquid and vapor, hence constituting advantage over prior art surfactant/solvent systems. DETAILED DESCRIPTION OF THE INVENTION In accordance with the invention, any water immis- 15 cible organic solvent may be employed. Such solvent should have a boiling point of 21-75°C, a density of at least 1.1 at 20°C, and should not form an azeotrope containing more than 2% by weight water. "Water- immiscible solvent" is intended to include solvents in 20 which water is not more than 0.1% by weight soluble. Preferably, the solvent has a boiling point of about 35- 49 β C, a density of about 1.4 to 1.6 weight percent at 20°C, and does not form an azeotrope containing more than about 0.5% of water. Suitable solvents include 2-5 trichloromonofluoromethane, 1,1,2-trichloro-l,2,2-tri- fluoroethane and azeotropic mixtures of the latter solvent with n-butanol or isobutanol, the isobutanol- trichlorotrifluoroethane mixture is preferred. The solvent generally contains a surfactant to aid 30 in displacement of water from articles to be dried. Preferably, the surfactant is soluble in the solvent and virtually insoluble in water. Any solvent-soluble surfactant which provides for displacement of water by the solvent may be used. Suitable surfactant include 35 long chain carboxylic acids containing an amidomethyl group such as a oleoyl sarcosine or alkyl phosphate esters neutralized with saturated aliphatic amines such as the 2-ethyhexyl a ine salt of di-n-octyl phosphate or an ethylene oxide-adduct type complex phosphate ester free acid. The latter is preferred. Such phosphate ester free acid surfactants are commercially available and contain a mixture of both mono and di-esters. The hydrophobic base may be aromatic or aliphatic, preferably aromatic. Typical of the complex phosphate ester-free acid surfactants are those of the ethylene oxide adduct type. These anionic products are mixtures of mono and diester, e.g. R0 ( CH wherein R is an alkylaryl radical and introduces a hydrophobic property; n has a value that signifies 2-10 moles of ethylene oxide reacted with one mole of hydrophobe. Preferably 3-5 moles of ethylene oxide are reacted with one mole of hydrophobe. The hydrophobe or hydrophobic group R is comprised of an alkyl group of three to nine carbon atoms, attach¬ ed to an aromatic nuclei such as benzene or naphthal¬ ene. The preferable hydrophobe is an aromatic alkyl phenol preferably nonyl phenol. Such surfactants include GAFAC RM-410 or GAFAC RL-210 (GAF Corp.); GAFAC RM-410 is preferred. Surfactant concentration may range from 150 ppm to 500 ppm, but a concentration between 50 and 500 ppm is preferred. It is further preferred that surfactant concentration be 100 ppm. The presence of certain alcohols (n-butanol or isobutanol) improve the wettability of the solvent and hence aid in the removal of water without contribution to non-volatile residue in the solvent. It is also preferred, that the alcohol form a constant-boiling compσ-Eiit σn with the solvent. The constant-boiling composition should contain 5 between 0.1 and 3.0% by weight of alcohol and preferably between 0.1 and 1.0% by weight of alcohol. The constant-boiling behavior is desired to maintain wettability characteristics in both liquid and vapor phases of the solvent composition during use (and to 10. avoid build-up of alcohol in the boiling sump of a typical, solvent dryer). It is further preferred that the a=lcx_τol be n-butanol at a composition between 0.5 and 0".75% by weight or isobutanol at a composition between 0.2 and 0.5% by weight. 15 in order that the invention may be more fully unde¬ rstood, the following examples are set forth for purpos¬ es of illustration. The specific enumeration of details therein should not be interpreted as a limitation except as expressed in the amended claims. 20 EXAMPLE 1 Constant boiling behavior of 1,1,2-trichloro-l,2,2- trifluoroethane and n-butanol, isobutanol. In order to maintain the contribution of wettabili¬ ty provided by a volatile additive such as an alcohol, 25 throughout the liquid and vapor zones of a typical dry¬ ing apparatus, the volatile additive and base solvent must form a constant boiling mixture. Thus, 1350 grams of a mixture of 3.0% by weight n-butanol in 1,1,2-tri- chloro-1,2,2-trifluoroethane was charged to a 3 liter 30 boiling flask fitted with a 21" Vigreaux column and Allihn reflux head. The mixture was allowed to reflux for one hour before distilling over any material. The boil-up rate was 15 ml/minute. The first overhead cut, 170 ml in volume, was discarded. A 30 minute period of ^ total reflux was provided between cuts. The next three cuts were combined and retained to serve as starting ma¬ terial for a seconds distillation. Cut size, head tem¬ peratures, and barometric pressure are given in Table 1. TABLE 1 First Distillation of n-butanol and 1 , 1 , 2-trichloro-l , 2, 2-trif luoroe thane Cut # Cut We ight , grams Head Temperature °C 2 262. 3 4 7. 5 3 267. 3 47. 5 4 285. 8 47. 5 Barometric Pressure - 743.0 mm Hg at 28.1°C The bottom portion was discarded. The recombined cuts 2, 3 and 4 were charged to the same apparatus as above and a second distillation performed in the same manner. Analysis of the distilled cuts was performed by gas chromatography. Results appear in Table 2. TABLE 2 Analysis of Distillation Cuts, Second Distillation of n-butanol and 1, 1, 2-trichloro-l, 2, 2-trif luoroethane Grams Weight, Head Cut Composition, % wt. Cut # grams Temperature % n-butanol 2 154.4 48.0 0.33 3 153.5 48.0 0.38 4 152.5 48.0 0.45 Barometric Pressure = 753.5 m Hg @ 24.0°C A third distillation was performed where 176.2 grams of a mixture containing 0.3% weight n-butanol served as starting material. This composition was formulated as the average of the cuts from the second distillation. Table 3 gives the composition of the cuts that resulted. TABLE 3 Cut Wfeight Head Cut Coϊrposition, % wt. Cut # grams Temperature °C n-butanol 2 152.4 48.0 0.22 3 153.3 48.0 0.23 4 153.0 48.0 0.28 Barometric Pressure = 749.2 mm Hg § 26.5°C 10. Tables 2 and 3 of this example illustrate the con¬ stant l__Q___L___cg; behavior of n-butanol in 1, 1, 2-trichloro- r, ? 2,,2 trd_£Iu:σroethane through successive distillation at a n-butanol concentration of about 0.2 to 0.5% by weight. 15 Similarly, isobutanol and 1, 1, 2-trichloro-l, 2,2- trifluoroethane were distilled. Data in Tables 4, 5 and 6 establish the constant boiling behavior of this pair. TABLE 4 0 First Distillation of isobutanol and 1,1,2-trichloro-1,2,2,-tricfluoroethane mixture, Charge Composition - 3% weight isobutanol in 1,1,2-trichloro-1,2,2-trifluoroethane Charge tfeight = 1632 grams Cut Weight, Head 5 Cut # grams Temperature °C 2 342.1 47.5 3 350.6 47.5 4 345.6 47.5 TABLE 5 D: Analysis of Cuts, Second Distillation of Isobutanol and 1,1,2-trichloro-l,2,2-trifluoroethane mixture Charge W_ight - 1028.9 grams Cut ϊfeight, Head Cut Cαπposition, % wt. 5 Cut # grams Temperature °C isobutanol 2 170.8 47.9 0.58 3 175.0 47.9 0.63 4 228.0 47.8 0.74 Bar tetric Pressure = 750.54 mm Hg @ 26.1°C TABLE 6 Final Distillation of Isobutanol in 1,1,2-trichloro-l,2,2-trifluoroethane Charge composition: 0.65 weight percent isobutanol in 1,1,2-trichloro-1,2,2-trifluoroethane Charge Weight = 1028.9 grams Cut Weight, Head Cut Composition, % wt. Cut # grams Temperature °C n-butanol 2 156.6 47.0 0.51 3 157.0 47.0 0.54 4 154.6 ' 47.0 0.60 Barcmetric Pressure - 749.2 mm Hg @ 26.5°C it can be seen from date in Tables 4 , 5 and 6 that isobutanol forms a constant-boiling composition with 1 , l , 2-trichloro- l , 2 , 2-trif luoroethane at about 0. 5 to 0. 75% by weight of isobutanol . EXAMPLE II The ability of a solvent to preferentially wet a substrate that is already wet with water was character¬ ized using the method below. A deionized water droplet of measured volume was expressed from a 10 microliter syringe with the resulting droplet adhered to the end of the needle. The needle was immersed just beneath the surface of given solvent composition and held in a beak¬ er at 99°F. Immediate removal of the needle followed. The process required a smooth motion of one second dura¬ tion. The droplet volume that would release to the sol- vent composition surface was recorded. It is apparent in Table 7 of the example, that the addition of certain alcohols to 1, 1,2-trichloro-l, 2,2-trifluoroethane increases the ability of the solvent to wet a substrate already wet with water. TABLE 7 Enhanced Wtettability of 1,1,2-trichloro-l,2,2-trifluoroethane Using Certain Alcohols Solvent Composition % Weight Water Droplet Volume Released, ml. 1) 1, 1,2-trichloro- 1, 2, 2-trif luoroethane 0.20 (Solv. A) 2) 0.54% isobutanol in 0.05 Solv. A 3) 0.22% n-butanol in 0.10 Solv. A 4) 0.5% isopropanol in " 0.10 Solv. A EXAMPLE III Water Removal Ef fectiveness The method used to determine water displacement times given in Table 7 is described below. Clean stainless steel screws , 1" x 1/8 " , roundhead , were used as received. Alumina ceramic slides , 1 1/2" x 1 1/2" , were found to be 100% water wettable as acquired, hence were not cleaned prior to use. To ensure a 100% water wettable surface on 1" x 3" glass slide, said slides were soaked overnight in a mixture of water, ammonia, methanol, and detergent. The slides were then rinsed consecutive, with deionized water, acetone, and methanol and finally allowed to air dry. A 600 ml glass beaker was charged with 400 ml of drying solvent and heated to boiling on a ceramic hot plate. Parts to be dried were first immersed in deion¬ ized water and then in boiling drying solvent. The time required to remove water from the part was recorded. In Table 8, four additive packages were evaluated for their ability to impart water displacement capabilities to base solvent, in this case, 1, 1,2-trichloro-l, 2, 2- trifluoroethane. In the case of the latter two additive packages, each when combined with 1,1,2-trichloro-l, 2,2- trifluoroethane constitute commercially available water displacement solvents as noted in Table 8 under solvent compositions. The commercial materials were used in this evaluation. Table 8 of this example shows that water displacement from glass, alumina, ceramic and stainless steel is demonstrated for the composition of the invention in time frames comparable to existing commercial formulations. TABLE 8 Effectiveness of Water Removal Solvent Composition Time Reguired to Remove Water, Seconds 1,1,2-trichloro- Stainless Steel 1,2,2-trifluoroethane Screws Alumina Ceramic with ... Trial 1 Trial 2 Trial 1 Trial 2 100 ppm phosphate ester free acid surfactant (2) and 0.54% isobutanol 10 100 ppm phosphate ester free acid surfactant (2) and 0.22% n-butanol 15 15 alkyl phosphate ester neutralized with saturated aliphatic amine (3) (Cotrmercially available as Du POnt Ereon ® TEFC) 10 10 0.25% sarcosine (4) surfactant and demsifers (Available ccmmercially as GENESOLV ® DRM from 105 (1) 195 (1) Allied-Signal Corp.) TABLE 8 (cont). Effectiveness of Water Removal Solvent Composition Time Required to Remove W_vter, Seconds 1,1,2-trichloro- 1,2,2-trifluoroethane Glass Slides with Trial 1 Trial 2 Trial 3 100 ppm phosphate ester free acid surfactant (2) and " 0.54% isobutanol 20 25 26 100 ppm phosphate ester free acid surfactant (2) and 0.22% n-butanol 26 20 21 alkyl phosphate ester neutralized with saturated aliphatic amine (3) (Commercially as Du Pont Freon ® TDFC) 10 0.25% sarcosine (4) surfactant and demsifers (Cαnmercially as Allied GENESOLV ® DRM) 85 195 240 (1) (1) No drying detected, the test was interrupted at this point. (2) GAFAC RM-410 surfactant (GAF Corporation). (3) 0.05 to 3.0% by weight of a mixture of mono-oxo-octyl and di- oxo-octyl phosphates or a mixture of mono(tridecyl) and bis(tridecyl) phosphates or a mixture of mono- and di-n-octyl and mono- and di-n-decyl phosphates neutralized with 2-ethylhexylamine or other suitable amines as disclosed in U.S. Patent 3,386,181. (4) N-lauryl sarcosine. However, N-cocoyl sarcosine or N-oleoyl sarcosine, and mixtures, may also be used as disclosed in U.S. Patent 4,401,584. EXAMPLE IV Solubility of Water in Water Removal Compositions Increased solubility of water in water removal sol¬ vents affects drying and dryer performance by prohibit- ing complete phase separation of water from solvents, increasing the tendency to form emulsions and necessar¬ ily allowing more water to inhabit the vapor zone of a dryer. Table 9 of this example illustrates the solubil- ity of water in various drying solvent compositions. In Table 9 of this example, as in Table 8 of Example III, the combination of 1,1,2-trichloro-l,2,2-trifluoroethane with each of the four listed additive packages were tested for water displacement ability. In the case of the latter two additive packages, their combination with 1,1,2-trichloro-l,2,2-trifluoroethane produces a result comprable to commercially available water displacement solvents. These two commercial solvents, as given in Table 9 under Solvent Composition, were used as such in testing. A microburet was used to titrate deionized water into 50 ml of drying solvent at room tempera¬ ture. The buret tip was held beneath the solvent surface. The solvent was stirred using a magnetic stirrer. The volume of water added t'hat caused cloudiness was taken to be the limit of solubility. TABLE 9 Solubility of Water Removal Compositions Volume of Dionized Water Required 5 Solvent Composition to Generate Cloudiness, ml. 1,1,2-trichloro-l,2,2- trifluoroethane with 100 ppm phosphate ester free acid surfactant (1) D- and 0.54% isobutanol 0.4 IQXI ppm phosphate ester free- acid surfactant (1) and 0.22% n-butanol 0.4 alkyl phosphate ester, amine salt (2) 5 (Du Pont Freon ® TDFC) 0.5 0.25% Sarcosine surfactants (3) (Allied GENESOLV ® DPM) 1.2 TT) GAFAC RM-410 surfactant (GAF Corp.) 0 (2) 0.05 to 3.0% by weight of a mixture of mono-oxo-octyl and di- oxo-octyl phosphates or a mixture of mono(tridecyl) and bis(tridecyl) phosphates or a mixture of mono- and di-n-octyl and di-n-decyl phosphates neutralized with 2-ethylhexylamine or other suitable amins as disclosed in U.S. Patent 3,386,181 (3) N-lauryl sarcosine. However, N-cocoyl or N-oleoyl sarcosine 5 and mixtures may also be used as disclosed in U.S. Patent 4,401,584. Various changes may be made in the reactants, proportions, and conditions within the disclosure is set O forth and therefore the invention is not to be limited except as set forth in the claims which follow. 5

Claims: What is Claimed is: 1. A binary azeotropic composition for removal of water from the surface of articles comprising: a) a fluorocarbon selected from the group consisting of trichloromonofluoromethane and 1,1,2- trichloro-1,2,2,-trifluoroethane; b) from about 0.1 to about 3 percent by weight, based on the weight of (a) of an alcohol selected from straight and branched chain alcohols of 3 to 8 carbon atoms; and c) from about 50 ppm to about 500 ppm of an ethylene oxide adduct phosphate ester free acid. 2. The composition of claim 1 wherein (b) is the azeotropic mixture of n-butanol and trichlorotrifluoroethane comprised of 0.20-0.50 weight percent of n-butanol and 99.80-99.50 trichlorotrifluoro¬ ethane and has a boiling point of about 48.0°F at the atmospheric pressure of about 749.2 mm Hg. 3. The composition of claim 1 wherein (b) is the azeotropic mixture of isobutanol and trichlorotrifluoro¬ ethane comprised of 99.50-99.25 weight percent of tri¬ chlorotrifluoroethane and 0.50-0.75 weight percent of isobutanol and has a boiling point of about 47.5°C (at the atmospheric pressure of about 749.2 mm Hg.)

Inventors: FIGIEL FRANCIS JOHN, ZYHOWSKI GARY JOHN, FIGIEL, FRANCIS, JOHN, ZYHOWSKI, GARY, JOHN
Applicants: ALLIED CORP, ALLIED CORPORATION
Application year: 1986
Main classification: C23G5
IPC codes: B01D12, C09K3, C23G5