WO1993005200A1

WO1993005200A1 - Azeotrope-like compositions of 1,1-dichloro-1-fluoroethane and perfluorocarbons and optionally nitromethane

Info

Publication number: WO1993005200A1
Application number: PCT/US1992/007308
Authority: WO
Inventors: Rajat Subhra Basu; Richard Mervil Hollister; Kane David Cook; Peter Brian Logsdon
Original assignee: Allied-Signal Inc.
Priority date: 1991-08-30
Filing date: 1992-08-28
Publication date: 1993-03-18
Also published as: AU2558292A

Abstract

Azeotrope-like compositions comprising 1,1-dichloro-1-fluoroethane and perfluorocarbons having 4 to 8 carbon atoms are stable and have utility as solvents in a variety of industrial cleaning applications including cold cleaning and defluxing of printed circuit boards and are useful as blowing agents.

Description

AZEOTROPE-LIKE COMPOSITIONS OF

1,1-DICHLORO-1-FLUOROETHANE AND PERFLUOROCARBONS

AND OPTIONALLY NITROMETHANE

FIELD OF THE INVENTION

This invention relates to azeotrope-like mixtures of

1,1-dichloro-1-fluoroethane and perfluorocarbons. These mixtures are useful in a variety of vapor degreasing, cold cleaning and solvent cleaning applications including defluxing and are useful as blowing agents.

BACKGROUND OF THE INVENTION

Vapor degreasing and solvent cleaning with fluorocarbon based solvents have found widespread use in industry for the degreasing and otherwise cleaning of solid surfaces, especially intricate parts and difficult to remove soils. In its simplest form, vapor degreasing or solvent cleaning consists of exposing a room temperature object to be cleaned to the vapors of a boiling solvent. Vapors condensing on the object provide clean distilled solvent to wash away grease or other contamination. Final evaporation of solvent from the object leaves behind no residue as would be the case where the object is simply washed in liquid solvent.

For difficult to remove soils where elevated temperature is necessary to improve the cleaning action of the solvent, or for large volume assembly line operations where the cleaning of metal parts and assemblies must be done efficiently and quickly, the conventional operation of a vapor degreaser consists of immersing the part to be cleaned in a sump of boiling solvent which removes the bulk of the soil, thereafter immersing the part in a sump containing freshly distilled solvent near room temperature, and finally exposing the part to solvent vapors over the boiling sump which condense on the cleaned part. In addition, the part can also be sprayed with distilled solvent before final rinsing.

Vapor degreasers suitable in the above-described operations are well known in the art. For example, Sherliker et al. in U.S. Patent 3,085,918 disclose such suitable vapor degreasers comprising a boiling sump, a clean sump, a water separator, and other ancillary equipment.

Cold cleaning is another application where a number of solvents are used. In most cold cleaning applications, the soiled part is either immersed in the fluid or wiped with rags or similar objects soaked in solvents and allowed to air dry. Fluorocarbon solvents, such as trichlorotrifluoroethane, have attained widespread use in recent years as effective, nontoxic, and nonflammable agents useful in degreasing applications and other solvent cleaning applications. Trichlorotrifluoroethane has been found to have satisfactory solvent power for greases, oils, waxes and the like. It has therefore found widespread use for cleaning electric motors, compressors, heavy metal parts, delicate precision metal parts, printed circuit boards, gyroscopes, guidance systems, aerospace and missile hardware, aluminum parts and the like.

The art has looked towards azeotrope or azeotrope-like compositions including the desired fluorocarbon components such as trichlorotrifluoroethane and other components which contribute additionally desired characteristics, such as polar functionality, increased solvency power, and stabilizers. Azeotropic or azeotrope-like compositions are desired because they exhibit a minimum or maximum boiling point and do not fractionate upon boiling. This behavior is desirable because in the previously described vapor degreasing equipment with which these solvents are employed, redistilled material is generated for final rinse-cleaning. Thus, the vapor degreasing system acts as a still. Unless the solvent composition exhibits a constant boiling point, i.e., is an azeotrope or azeotrope-like, fractionation will occur and undesirable solvent distribution may act to upset the cleaning and safety of processing. Preferential evaporation of the more volatile components of the solvent mixtures, which would be the case if they were not azeotropic or azeotrope-like, would result in mixtures with changed compositions which may have less desirable properties, such as lower solvency towards soils, less inertness towards metal, plastic or elastomer components, and increased flaiπmability and toxicity.

The art is continually seeking new fluorocarbon based azeotropic or azeotrope-like mixtures which offer alternatives for new and special applications for vapor degreasing and other cleaning applications. Currently, of particular interest, are fluorocarbon based azeotrope-like mixtures which are considered to be stratospherically safe substitutes for presently used fully halogenated chlorofluorocarbons. The latter are suspected of causing environmental problems in connection with the earth's protective ozone layer. Mathematical models have substantiated that hydrochlorofluorocarbons, such as 1,1-chloro-1-fluoroethane (HCFC-141b), will not adversely affect atmospheric chemistry, being negligible contributors to ozone depletion and to green-house global warming in comparison to the fully halogenated species. The art is also seeking new fluorocarbon azeotrope-like mixtures which are useful as blowing agents. Fluorocarbons such as trichlorofluoromethane have been used commercially as auxiliary blowing agents for flexible foams and as primary blowing agents for rigid foams. Polyurethane foams are manufactured by reacting and foaming a mixture of ingredients comprising in general an organic isocyanate, such as pure or crude toluene diisocyanate or a polymeric diisocyanate, with an appropriate amount of polyol or mixture of polyols, in the presence of a volatile liquid blowing agent, which vaporizes during the reaction, causing the polymerizing mixture to foam. The reactivity of these ingredients is enhanced through the use of various additives such as amine and/or tin catalysts and surfactant materials which serve to control and adjust cell size as well as to stabilize the foam structure during its formation.

Flexible polyurethane foams are generally manufactured using an excess of diisocyanate which reacts with the water also included as a raw material, producing gaseous carbon dioxide, causing foam expansion. Flexible foams are widely used as cushioning materials in items such as furniture, bedding and automobiles. Auxiliary physical blowing agents such as methylene chloride and/or CFC-11 are required in addition to the water/diisocyanate blowing mechanism in order to produce low density, soft grades of flexible polyurethane foam.

Rigid polyurethane foams are almost exclusively expanded using CFC-11 as the blowing agent. Some rigid foam formulations do incorporate small amounts of water in addition to the CFC-11, but the CFC-11 is the major blowing agent component. Other formulations sometimes use small amounts of the more volatile dichlorodifluoromethane (CFC-12) in addition to CFC-11 for producing so-called froth-type foams. Rigid foams are closed-cell foams in which the CFC-11 vapor is trapped in the matrix of cells. These foams offer excellent thermal insulation characteristics, due in part to the low vapor thermal conductivity of CFC-11, and are used widely in thermal insulation applications such as roofing systems, building panels, refrigerators and freezers and the like. DESCRIPTION OF THE INVENTION

In accordance with the invention, novel azeotrope-like or constant-boiling compositions have been discovered comprising 1,1-dichloro-1-fluoroethane and perfluorocarbons having 4 to 8 carbon atoms and optionally nitromethane. The present azeotrope-like compositions wherein the perfluorocarbons have 5 to 7 carbon atoms are useful as solvents and are found to have better compatibility with polymeric materials. The present azeotrope-like compositions are also found to have good solubility with other fluorinated compounds and thus, may be used as carrier fluids for fluorinated compounds such as fluorolubricants used in disk drives.

The present azeotrope-like compositions wherein the perfluorocarbons have 4 to 6 carbon atoms are useful as blowing agents.

The term "perfluorocarbon" as used herein means compounds having carbon and fluorine atoms therein. The perfluorocarbon having 4 to 8 carbon atoms is selected from the group consisting of perfluorobutane; perfluoro- 2-methylpropane; perfluoropentane; perfluoro-2- methylbutane; perfluoro-2,2-dimethylpropane; perfluorohexane; perfluoro-2-methylpentane; perfluoro-3- methylpentane; perfluoro-2,3-dimethylbutane; perfluoro- 2,2-dimethylbutane; perfluoroheptane; perfluoro-2- methylhexane; perfluoro-3-methylhexane; perfluoro-2,3- dimethylpentane; perfluoro-2,4-dimethylpentane; perfluoro-2,2-dimethylpentane; perfluoro-3,3- dimethylpentane; perfluoro-2,2,3-trimethylbutane; perfluorooctane; perfluoro-2-methylheptane; perfluoro-3- methylheptane; perfluoro-4-methylheptane; perfluoro-2,3- dimethylhexane; perfluoro-2,4-dimethylhexane; perfluoro- 2,5-dimethylhexane; perfluoro-3,4-dimethylhexane; perfluoro-2,2-dimethylhexane; perfluoro-3,3- dimethylhexane; perfluoro-2,3,4-trimethylpentane; perfluoro-2,2,3-trimethylpentane; perfluoro-2,3,3- trimethylpentane; perfluoro-2,2,3,3-tetramethylbutane; perf luoro - 1 , 3 - dimethylcyclohexane ; perfluoromethylcyclohexane; perfluoromethylcyclopentane; and tetradecafluoro-2-methylpentane.

Perfluoro-1,3-dimethylcyclohexane; perfluorohexane; perfluoro(methylcyclohexane); perfluorooctane; perfluoropentane; and perfluoroheptane are available commercially. The other perfluorocarbons may be prepared by using known methods for the preparation of perfluorocarbons. Novel azeotrope-like compositions comprise from about 25 to about 99.95 weight percent 1,1-dichloro-1- fluoroethane and from about 0.05 to about 75 weight percent perfluorocarbon having 4 to 8 carbon atoms and from 0 to about 1 weight percent nitromethane which boil between about 16°C and about 32°C at 760 mm Hg (101 kPa) wherein said perfluorocarbon is not perfluoro-1,2- dimethylcyclobutane.

Commercially available perf luorohexane comprises at least 75% perf luoro-n-hexane and the remainder is lin e a r and branched perfluorocarbons having 5 to 18 carbon atoms, perfluoromethylpentane, and dodecafluorocyclohexa n e **Commercially available perfluoroheptane comprises at least 75% perfluoro-n-heptane and the

remainder is linear and branched perfluorocarbons having 5 to 18 carbon atoms.

The precise or true azeotrope composition has not been determined but has been ascertained to be within the indicated ranges. Regardless of where the true azeotrope lies, all compositions within the indicated ranges, as well as certain compositions outside the indicated ranges, are azeotrope-like, as defined more particularly below.

For the purpose of this discussion, the term "azeotrope-like composition" is intended to mean that the composition behaves like an azeotrope, i.e. has constant-boiling characteristics or a tendency not to fractionate upon boiling or evaporation. Such compositions may or may not be a true azeotrope. Thus, in such compositions, the composition of the vapor formed during boiling or evaporation is identical or substantially identical to the original liquid composition. Hence, during boiling or evaporation, the liquid composition, if it changes at all, changes only to a minimal or negligible extent. This is to be contrasted with non-azeotrope-like compositions in which during boiling or evaporation, the liquid composition changes to a substantial degree. Inhibitors may be added to the present azeotrope-like compositions to inhibit decomposition of the compositions; react with undesirable decomposition products of the compositions; and/or prevent corrosion of metal surfaces. Any or all of the following classes of inhibitors may be employed in the invention: alkanols having 4 to 7 carbon atoms, nitroalkanes having 2 to 3 carbon atoms, 1,2-epoxyalkanes having 2 to 7 carbon atoms, phosphite esters having 12 to 30 carbon atoms, ethers having 3 or 4 carbon atoms, unsaturated compounds having 4 to 6 carbon atoms, acetals having 4 to 7 carbon atoms, ketones having 3 to 5 carbon atoms, and amines having 6 to 8 carbon atoms. Other suitable inhibitors will readily occur to those skilled in the art. The inhibitors may be used alone or in mixtures thereof in any proportions. Typically, up to about 2 percent based on the total weight of the azeotrope-like composition of inhibitor might be used. The azeotrope-like compositions of the invention are useful as solvents in a variety of vapor degreasing, cold cleaning and solvent cleaning applications including defluxing and dry cleaning. In one process embodiment of the invention, the azeotrope-like compositions of the invention may be used as carrier fluids for compounds which are to be deposited or coated on the surface of a substrate by dissolving the compounds in the azeotrope-like compositions and passing the resulting composition over the surface of a substrate.

In one process embodiment of the invention, the azeotrope-like compositions of the invention may be used to clean solid surfaces by treating said surfaces with said compositions in any manner well known to the art such as by dipping or spraying or use of conventional degreasing apparatus. The present method dissolves or removes most contaminants from the surface of a substrate. For example, the present method dissolves or removes organic contaminants such as mineral oils from the surface of a substrate. Under the term "mineral oils", both petroleum-based and petroleum-derived oils are included. Lubricants such as engine oil, machine oil, and cutting oil are examples of petroleum-derived oils. The present method also dissolves or removes synthetic, semi- synthetic, and water emusifiable oils. The present method is particularly useful in dissolving or removing perfluorinated contaminants.

The present method also removes water from the surface of a substrate. The method may be used in the single-stage or multi-stage drying of objects.

The present method may be used to clean the surface of inorganic and organic substrates. Examples of inorganic substrates include metallic substrates, ceramic substrates, and glass substrates. Examples of organic substrates include polymeric substrates such as polycarbonate , polystyrene , and acrylonitrile-butadiene-styrene. The method also may be used to clean the surface of natural fabrics such as cotton, silk, fur, suede, leather, linen, and wool. The method also may be used to clean the surface of synthetic fabrics such as polyester, rayon, acrylics, nylon, and blends thereof, and blends of synthetic and natural fabrics. It should also be understood that composites of the foregoing materials may be cleaned by the present method. The present method may be particularly useful in cleaning the surface of polycarbonate, polystyrene, and acrylonitrile-butadiene-styrene substrates. The present method may be used in vapor degreasing, solvent cleaning, cold cleaning, dewatering, and dry cleaning. In these uses, the object to be cleaned is immersed in one or more stages in the liquid and/or vaporized solvent or is sprayed with the liquid solvent. Elevated temperatures, ultrasonic energy, and/or agitation may be used to intensify the cleaning effect.

In another process embodiment of the invention, the azeotrope-like compositions of the invention may be used to form polyurethane and polyisocyanurate foams by reacting and foaming a mixture of ingredients which will react to form polyurethane and polyisocyanurate foams in the presence of a blowing agent comprising the azeotrope-like compositions.

The compositions of the invention may be used as auxiliary or primary blowing agents for the preparation of polyurethane foams. Polyurethanes are polymers of polyols and isocyanates. A wide variety of polyols may be employed as disclosed in the prior art, such as polyether polyols and polyester polyols. Illustrative suitable polyether polyols are polyoxypropylene diols having a molecular weight of between about 1,500 and 2,500, glycerol based polyoxypropylene triols having a molecular weight of between about 1,000 and 3,000, trimethylol-propane-based triols having a hydroxyl number of about 390, sorbitol-based hexol having a hydroxyl number of about 490, and sucrose-based octols having a hydroxyl number of about 410. Illustrative suitable polyester polyols are the reaction products of polyfunctional organic carboxylic acids such as succinic acid, adipic acid, phthalic acid and terephthalic acid with monomeric polyhydric alcohols such as glycerol, ethylene glycol, trimethylol propane, and the like.

A wide variety of isocyanates may be employed as disclosed in the prior art. Illustrative suitable isocyanates are the aliphatic isocyanates such as hexamethylene diisocyanate, aromatic isocyanates such as toluene diisocyanate (TDI), preferably the isomeric mixture containing about 80 weight percent of the 2,4 isomer and 20 weight percent of the 2,6 isomer, crude TDI, crude diphenylmethane diisocyanate and polymethylpolyphenyl isocyanate.

The amount of blowing agent to be employed will depend on whether it is to be used as a primary or auxiliary blowing agent and the nature of the foams desired, i.e, whether flexible or rigid foam is desired.

The amount of blowing agent employed can be readily determined by persons of ordinary skill in the art.

Generally, about 1 to about 15 weight percent based on the polyurethane forming reaction mixture is employed and preferably, between about 5 to about 10 weight percent.

As is well known in the art, the urethane-forming reaction requires a catalyst. Any of the well known urethane-forming catalysts may be employed. Illustrative organic catalysts are the amino compounds such as triethylenediamineN,N,N',N'-tetramethylethylenediamine, dimethylethanolamine, triethylamine and N-ethyl- morpholine. Inorganic compounds such as the non-basic heavy metal compounds as illustrated by dibutyl tin dilaurate, stannous octoate and manganese acetyl acetonate may also be used as catalysts. In general, the amount of catalyst present in the foam forming mixture ranges from about 0.05 to about 2 parts by weight per 100 parts by weight of the polyol component.

As is well recognized in the art, a variety of other additives may be incorporated in the foam-forming mixtures including stabilizers, such as silicone oils; cross-linking agents such as 1,4-butanediol, glycerol, triethanolaminemethylenedianiline; plasticizers, such as tricresyl phosphate and dioctyl phthalate; antioxidants; flame retardants; coloring material; fillers; and antiscorch agents. Polyurethane foams are prepared according to the invention by reacting and foaming a mixture of ingredients which will react to form the foams in the presence of a blowing agent according to the invention. In practice, the foam forming ingredients are blended, allowed to foam, and are then cured to a finished product. The foaming and curing reactions, and conditions therefor are well-known in the art and do not form a part of this invention. Such are more fully described in the prior art relating to the manufacture of polyurethane foams. Thus, for example, the polyether may first be converted to a polyether-polyisocyanate prepolymer by reaction in one or more stages with an excess amount of isocyanate at temperatures from about 75°-125°C. or by reacting the polyol and the isocyanate together at room temperature in the presence of a catalyst for the reaction such as

N-methylmorpholine. The prepolymer would then be charged to the foam-forming mixture as the foam producing ingredient with or without the addition of additional isocyanate and foamed in the presence of the blowing agent, optionally with additional polyol cross-linking agents and other conventional optional additives. Heat may be applied to cure the foam. If a prepolymer is not employed, the polyether, isocyanate, blowing agent and other optional additives may be reacted simultaneously to produce the foam in a single stage.

The 1,1-dichloro-1-fluoroethane; perfluoroccrbon; and nitromethane components of the novel solvent azeotrope-like compositions of the invention are known materials.

The 1,1-dichloro-1-fluoroethane component of the invention has good solvent properties. The perfluorocarbons also have good solvent capabilities for perfluorinated compounds. Thus, when these compounds are combined in effective amounts, an efficient azeotrope-like solvent results. It should be understood that the present compositions may include additional components so as to form new azeotrope-like compositions. Any such compositions are considered to be within the scope of the present invention as long as the compositions are azeotrope-like or essentially azeotrope-like and contain all of the essential components described herein.

The present invention is more fully illustrated by the following non- limiting Examples .

EXAMPLE 1

The azeotropic properties of 1,1-dichloro-1- fluoroethane and perfluoropentane (85% n-perfluoropentane with the remainder a mixture of perfluorinated alkanes having 5 to 18 carbon atoms) were determined using ebulliometric techniques.

A microebulliometer which consisted of a 15 milliliter round bottom double neck flask containing a magnetic stirbar and heated with an electrical heating mantel was used. Approximately three milliliters of the lower boiling material, perfluoropentane, was charged into the microebulliometer and HCFC-141b was added in small measured increments by an automated syringe capable of injecting microliters. The temperature was measured using a platinum resistance thermometer and barometric pressure was measured. An approximate correction to the boiling point was done to obtain the boiling point at 760 mm Hg. A minimum boiling azeotrope was observed. We also observed that compositions of about 25-85 wt%/15-75 wt% HCFC-141b/perfluoropentane respectively are constant boiling at 19.3°C ± about 1°C at 760 mmHg.

EXAMPLE 2

Example 1 was repeated except that perfluoromethylcyclopentane (purity 90%) was used instead of perfluoropentane. Approximately 2.8 milliliters of the lower boiling material, HCFC-141b, were initially charged into the microebulliometer and perfluoromethylcyclopentane was added in small measured increments by an automated syringe capable of injecting microliters. A minimum boiling azeotrope was observed. We also observed that compositions of about 25-95 wt%/5- 75 wt% HCFC-141b/ perfluoropentane respectively are constant boiling at 27.3°C ± about 1°C at 760 mmHg

EXAMPLE 3

Example 1 was repeated except that perfluorohexane was used instead of perfluoropentane. The perfluorohexane used was FC-72^® which is available from 3M and comprises at least 75% perfluoro-n-hexane and the remainder is linear and branched perfluorocarbons having 5 to 18 carbon atoms. Three milliliters of HCFC-141b were initially charged to the ebulliometer. A minimum boiling azeotrope was observed. We also observed that compositions of about 25-92.7wt%/7.3-75wt% HCFC- 141b/perfluorohexane respectively are constant boiling at 27.7°C ± about 1°C. EXAMPLE 4

Example 1 was repeated except that perfluoromethylcyclohexane was used instead of perfluoropentane. Three milliliters of HCFC-141b were initially added to the ebulliometer. A minimum boiling azeotrope was observed. We also observed that compositions of about 60-99.95wt%/0.05-40wt% HCFC- 141b/perfluoromethylcyclohexane respectively are constant boiling at 31.6°C ± about 0.4°C.

EXAMPLE 5

Example 1 was repeated except that perfluoro-1,3- dimethylcyclohexane was used instead of perfluoropentane. Three milliliters of HCFC-141b were initially added to the ebulliometer. The results showed that compositions of about 90-99.95wt%/0.05-10wt% HCFC-141b/perfluoro-1,3- dimethylcyclohexane respectively are constant boiling at 32°C ± about 2°C at 760 mmHg. EXAMPLE 6

Example 1 was repeated except that perfluoroheptane was used instead of perfluoropentane. The perfluoroheptane used was FC-84^® which is available from 3M and comprises at least 75% perfluoro-n-heptane and the remainder is linear and branched perfluorocarbons having 5 to 18 carbon atoms. Three milliliters of HCFC-141b were initially charged to the ebulliometer. A minimum boiling azeotrope was observed. We also observed that compositions of about 40-99.95wt%/0.05-60wt% HCFC- 141b/perfluoroheptane are constant boiling at 31.4°C ± about 0.6°C at 760 mmHg.

EXAMPLES 7 THROUGH 34

The present invention also provides the azeotrope- like compositions of Tables VII, VIII, and IX below:

EXAMPLES 35 THROUGH 68

Each of Examples 1 through 34 is repeated except that nitromethane is also present in an amount up to about 1 weight percent. EXAMPLE 69

An azeotrope-like composition of 80 weight percent

HFCF-141b and 20 weight percent perfluorohexane, which is from 3M under the name FC-72^®, was used to dissolve a perfluorinated ether. The perfluorinated ether used was

FOMBLIN^® which is used as a lubricant in disk drives.

The azeotrope-like composition dissolved over 12 weight percent of the perfluorinated ether. This mixture of the azeotrope- like composition and the perfluorinated ether was applied to magnetic disks. The azeotrope-like composition evaporated and the perfluorinated ether lubricant was deposited on the magnetic disk substrate.

Thus, the present azeotrope-like compositions are useful as carrier fluids. HCFC-141b alone does not dissolve perfluorinated ethers and as a result, HCFC-141b alone is not useful as a carrier fluid for perfluorinated ethers. EXAMPLES 70 THROUGH 138

Performance studies are conducted wherein metal coupons are cleaned using the present azeotrope-like compositions as solvents. The metal coupons are soiled with various types of oils and heated to 93°C so as to partially simulate the temperature attained while machining and grinding in the presence of these oils.

A stainless steel beaker with condensing coils near its lips is used. Each azeotrope-like composition is boiled in the beaker which condenses on the coils providing adequate vapor and the condensed solvent drips back to the beaker.

The metal coupons are held in the solvent vapor and then vapor rinsed for a period of 15 seconds to 2 minutes depending upon the oils selected. The azeotrope-like compositions of Examples 1 through 68 are used as the solvents. Cleanliness testing of coupons are done by measurement of the weight change of the coupons using an analytical balance to determine the total residual materials left after cleaning.

EXAMPLES 139 THROUGH 140

Acrylic and polycarbonate parts were refluxed in HCFC-141b alone and blends of HCFC-141b and commercially available perfluorohexane for 10 minutes; this reflux time is typical in commercial cleaning applications. HCFC-141b alone had an adverse effect on polycarbonate, polystyrene, and acryonitrile-butadiene-styrene. The blends used were as in Table X below. Unexpectedly, the blends showed no adverse effect on the polymeric materials.

EXAMPLES 141 THROUGH 209

Free-rise rigid polyurethane foam is prepared from the formulations specified in Table XI using Martin Sweets Co. Modern Module III urethane foam machine at a delivery rate of 15 pounds per minute by using the azeotrope-like compositions of Examples 1 through 68 as blowing agents. This polyurethane formulation is one example of a pour- in-place rigid polyurethane formulation which might be used as an applicance insulation.

The polyol is an aromatic amine polyol which is available as P-824^® from BASF Corporation. The surfactant is Tegostab ^®B-8404 available from Goldschmidt Chemical Company. The catalyst is Polycat-8^® which is N,N-dimethylcyclohexylamine from Air Products and Chemicals, Inc. The polyisocyanate is polymethylene polyphenylisocyanate which is available as Lupranate M20S^® (1.29 index) from BASF Corporation.

EXAMPLES 210 THROUGH 278

Polyurethane modified polyisocyanurate foam is prepared from the formulations specified in Table XII using Martin Sweets Co. Modern Module III urethane foam machine at a delivery rate of 15 pounds per minute by using the azeotrope-like compositions of Examples 1 through 68 as blowing agents. This polyurethane modified polyisocyanurate formulation is one example of formulation which might be used as a rigid laminated boardstock.

The polyol is a polyester polyol which is available as Stepanpol PS-2502A^® from Stepan Company. The surfactant is Tegostab ^®B-8404 available from Goldschmidt Chemical Company. The potassium octoate is DABCO^® K-15 available from Air Products and Chemicals, Inc. The amine catalyst is DABCO^® TMR-30 available from Air Products and Chemicals, Inc. The polyisocyanate is polymethylene polyphenylisocyanate which is available as Lupranate M20S^® (1.29 index) from BASF Corporation.

Claims

What is claimed is:

1. Azeotrope-like compositions consisting essentially of about 25 to about 99.95 weight percent 1,1-dichloro-1-fluoroethane and about 0.05 to about 75 weight percent perfluorocarbon having 4 to 8 carbon atoms and 0 to about 1 weight percent nitromethane which boil between about 16°C and about 32°C at 760 mm Hg wherein said perfluorocarbon is not perfluoro-1,2- dimethylcyclobutane.

2. The azeotrope-like compositions of claim 1 wherein said perfluorocarbon having 4 to 8 carbon atoms is selected from the group consisting of perfluoropentane, perfluoromethylcyclopentane, perfluorohexane, perfluoromethylcyclohexane, perfluoro- 1,3-dimethylcyclohexane, and perfluoroheptane wherein said perfluoropentane compositions boil at about 19.3°C at 760 mm Hg, said perfluoromethylcyclopentane compositions boil at about 27.3°C at 760 mm Hg, said perfluorohexane compositions boil at about 27.7°C at 760 mm Hg, said perfluoromethylcyclohexane compositions boil at about 31.6°C at 760 mm Hg, said perfluoro-1,3- dimethylcyclohexane compositions boil at about 32°C at 760 mm Hg, and said perfluoroheptane compositions boil at about 31.4ºC at 760 mm Hg.

3. The azeotrope-like compositions of claim 2 consisting essentially of about 25 to about 85 weight percent said 1,1-dichloro-1-fluoroethane and about 15 to about 75 weight percent said perfluoropentane and from 0 to about 0.5 weight percent nitromethane.

4. The azeotrope-like compositions of claim 2 consisting essentially of about 25 to about 95 weight percent said 1,1-dichloro-1-fluoroethane and from about 5 to about 75 weight percent said perfluoromethylcyclopentane and from 0 to about 1 weight percent nitromethane.

5. The azeotrope-like compositions of claim 2 consisting essentially of about 25 to about 92.7 weight percent said 1,1-dichloro-1-fluoroethane and from about 7.3 to about 75 weight percent said perfluorohexane and from 0 to about 1 weight percent nitromethane.

6. The azeotrope-like compositions of claim 2 consisting essentially of about 60 to about 99.95 weight percent said 1,1-dichloro-1-fluoroethane and from about 0.05 to about 40 weight percent said perfluoromethylcyclohexane and from 0 to about 1 weight percent nitromethane.

7. The azeotrope-like compositions of claim 2 consisting essentially of about 90 to about 99.5 weight percent said 1,1-dichloro-1-fluoroethane and from about 0.05 to about 10 weight percent said perfluoro-1,3- dimethylcyclohexane and from 0 to about 1 weight percent nitromethane.

8. The azeotrope-like compositions of claim 2 consisting essentially of about 40 to about 99.95 weight percent said 1,1-dichloro-1-fluoroethane and from about 0.05 to about 60 weight percent said perfluoroheptane and from 0 to about 1 weight percent nitromethane.

9. The azeotrope-like compositions of claii 2 wherein said inhibitor is selected from the group consisting of alkanols having 4 to 7 carbon atoms, nitroalkanes having 2 to 3 carbon atoms, 1,2-epoxyalkanes having 2 to 7 carbon atoms, phosphite esters having 12 to 30 carbon atoms, ethers having 3 or 4 carbon atoms, unsaturated compounds having 4 to 6 carbon atoms, acetals having 4 to 7 carbon atoms, ketones having 3 to 5 carbon atoms, and amines having 6 to 8 carbon atoms.

10. A method of depositing or coating compounds on the surface of a substrate comprising the steps of:

(a) dissolving said compounds in said azeotrope-like compositions of claim 2; and

(b) passing the composition resulting from step (a) over said substrate surface.

11. The method of claim 10 wherein said compound is perfluorinated.

12. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 3 as solvent.

13. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 4 as solvent.

14. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 5 as solvent.

15. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 6 as solvent.

16. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 7 as solvent.

17. A method of dissolving contaminants or removing contaminants from the surface of a substrate which comprises the step of:

using said azeotrope-like composition of claim 8 as solvent.

18. A method of preparing polyurethane and polyisocyanurate foams which comprises reacting and foaming a mixture of ingredients which will react to form the polyurethane and polyisocyanurate foams in the presence of a blowing agent comprising said azeotrope- like compositions of claim 2 wherein said perfluorocarbon has 4 to 6 carbon atoms.