CA1045529A - Non-dripping heat resistant dye penetrant and method of dye penetrant inspection - Google Patents
Non-dripping heat resistant dye penetrant and method of dye penetrant inspectionInfo
- Publication number
- CA1045529A CA1045529A CA252,416A CA252416A CA1045529A CA 1045529 A CA1045529 A CA 1045529A CA 252416 A CA252416 A CA 252416A CA 1045529 A CA1045529 A CA 1045529A
- Authority
- CA
- Canada
- Prior art keywords
- dye
- surfactant
- silica
- parts
- dye penetrant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
- C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
- C09B67/0071—Process features in the making of dyestuff preparations; Dehydrating agents; Dispersing agents; Dustfree compositions
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/91—Investigating the presence of flaws or contamination using penetration of dyes, e.g. fluorescent ink
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- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Biodegradable water washable dye penetrant composition in the form of a gel for use in non-destructive dye penetrant inspec-tion of parts, and which can be applied to part surfaces at varying angles without dripping, and being resistant to decomposition and liquefaction when applied to heated surfaces, e.g. up to about 300°F
such composition consisting essentially of (1) an organic dye, pre-ferably a fluorescent dye, (2) a carrier or solvent for said dye, in the form of a surfactant comprised of certain straight chain, primary, aliphatic oxyalkylated alcohols, and (3) silica, particularly fumed silica, such silica employed e.g. in a propor-tion of 5 parts per 1 part of the sum of the other dye penetrant components, including biodegradable surfactant and dye, by volume.
The biodegradable heat resistant dye penetrant composition of the invention is a simple formulation which does not require the use of mixtures of conventional solvents and wetting agents and which avoids liquefaction and dripping and also avoids the genera-tion of obnoxious fumes, as distinct from prior art compositions.
Biodegradable water washable dye penetrant composition in the form of a gel for use in non-destructive dye penetrant inspec-tion of parts, and which can be applied to part surfaces at varying angles without dripping, and being resistant to decomposition and liquefaction when applied to heated surfaces, e.g. up to about 300°F
such composition consisting essentially of (1) an organic dye, pre-ferably a fluorescent dye, (2) a carrier or solvent for said dye, in the form of a surfactant comprised of certain straight chain, primary, aliphatic oxyalkylated alcohols, and (3) silica, particularly fumed silica, such silica employed e.g. in a propor-tion of 5 parts per 1 part of the sum of the other dye penetrant components, including biodegradable surfactant and dye, by volume.
The biodegradable heat resistant dye penetrant composition of the invention is a simple formulation which does not require the use of mixtures of conventional solvents and wetting agents and which avoids liquefaction and dripping and also avoids the genera-tion of obnoxious fumes, as distinct from prior art compositions.
Description
~0455~3 BACKGROUND OF T~E INVENTION
This invention relates to an improved non-dripping, heat resistant biodeyradable dye penetrallt composltion and method for non-destructively testing material specimens to locate and identify surface voids, cracks or defects. The invention is especially concerned with a novel dye penetrant composition having the above characteristics, and which can be applied to heated surfaces of an object without decomposi-tion or liquefaction, and without generating fumes, and which in addition has the properties of being readily water washable, and sensitive for disclosing a wide range of defective con-ditions in parts, employing as solvent or vehicle certain .
: ~ :
~ ..
~: :
~ :: : : :
4SSZ~
biadegradable nonionic surfactants in the form of certain oxy~
alkylated alcohols, and mixtures thereof; and to a method of utilizing such d~ penetrant composition for non-destru~-tive testing of parts, particularly parts heated to elevated temperature.
In known penetrant inspection methods for xapid location and evaluation of surface flaws or cracks in test bodies or parts, a dye penetrant composition, preferably con- ;
taining a fluorescent dye, and which will penetrate the open-ings of the surface cracks or flaw~ in the part, is applied to the surface of the test body, and the excess penetrant ~;
composition is removed from the surface of the body. A
developer composition may then be applied to the part surface, which acts as a wick and causes the liquid pcnetrant contain-ing the fluorescent dye, which was retained in the cracks or surface flaws, to be drawn up out of the surface defects by ¢apillary action. The part is then exposed to appropriate lighting conditions, such as invisible fluorescigenous light, and the location o~ the surfacs flaws is revealed by the emission of visible fluorescent light by the penetrant clye which was retained in the cracks or flaw~ after the penetrant composition wa~ removed from the sur~ace of the part.
For best efficiency, partic~larly for the detection . .
and location of minute surface cracks and flaws, as well as intermediate size and gross cracks, it is necessary that the ~ . . .
dye penetrant composltion have high sensiti~ity.
In addition, stability of the penetrant solution is essential without the necessity for carefully balancing the '!' ,.'~.'''., .. .: . ~ . . .. . ....
various liquid components of a dye penetrant solution in order to obtain efficient penetration of the solution into the cracks and flaws of a part, dye solubility, wetting action and washability control.
An additional criterion has recently developed also with respect to dye penetrant solutions and compositions. Generally, dye penetrant solutions presently being usecl and containing sol~
vents and wetting agents present a disposal problem in that they are substantially non-biodegradable, that i~;, they are very dif-ficult to decompose by bacteria in sewage disposal plants. Hence . ., :. .
the necessity for the development of dye penetrant solutions and compositions which are biodegradable, that is which employ dye solvents and carriers which are biodegradable, and are readily available despite the petrochemical shortage, has attained con-siderable importance.
Novel dye penetrants can be used which have improved washability and sensitivity characteristics, and which are biode-gradable, containing as the vehicle for the dye, certain biodegrad-able nonionic oxyalkylated alcbh~ls.
Further, penetrant inspection of hot surfaces of parts, e~pecially those of overhead and vertical orientation, present a particular problem. Conventional penetrants when employed under these conditions become extremely liquefied, produce obnoxious fumes, drip and change in sensitivity due to loss of volatiles. A conven-tional dye penetrant employed under these conditions and thinned by the action of heat creates a messy condition because it cannot be contained in prescribed . ., ~
~ - .
:
.. ~ ~, . .
10~S529 areas of parts or assemblies being inspected. ~ -In my Pahent No. 3,465,146 there is disclosed a dye ~
penetrant which comprises conventional liquid organic dye ~ -carriers or vehiole~ such as ~-methyl-2-pyrrolidone, and a thickening agent such as silica. However, although such composition is effective when applied to surfaces which are . - -at approximately ambient temperature, when applied to heated surfaces, e.g. surfaces heated at temperature in excess of ~
about 100 F, the composition dries and forms a powdery `~;
material and fails to perform effectively. In addition, the dye penetrant compositions of this patent are not biodegrad- -able.
Accordingly, an object of the present invention i8 the provision of a biodegradable heat resistant dye penetrant ,: .: ., composition which i~ a simple formulation and which does not ~: .. . .
require the use of mixtures of conventional solvents and wetting agent~, and which is foxmed of an essentially single or sole vehicle or carrier or the dye in the form of a bio-degradable nonionic surfactant, and which is heat stable, has excellent sensitivity and is essentially non-flammable and ; non-toxic. A particular object of the invention is to provide a dye penetrant composition of the above noted type, and which ~. ..-. .
in~orporates an additive which converts the dye penetrant composition to a gel-like consistency, permitting the dye .
pe~etrant composition to be applied to heated surfaces of objects disposed at~varying angles, without becoming lique~ied and dxipping, and without generating obnoxious fumes, substan-tially without afecting the biodegradability, penetrability :
: , .
', : ~ :
1C)455;Z9 or sensitivity of the dye penetrant. A still further object is the provision of procedure employing such novel heat stable biodegradable dye penetrant composition for inspection of cracks, flaws and metallurgical conditions in~tructural compo- -nents, particularly parts heated to elevated temperature, with-out dripping.
DESCRIPTION OF THE INVENTIO~
According to the present invention, it has been found that the above objects and advantages can be accomplished by an improved heat resistant and non-dripping dye penetrant, having good sensitivity for detection of cracks and defects in metal surfaces, and which is biodegradable, is provided by employing as a solvent or carrier for the dye, e.g., fluorescent dye, a biodegradable nonionic surfactant and incorporating a substan-tial proportion of silica (silicon dioxide), preferably in pow-dered form. Upon incorporation of the powdered silica into the dye penetrant containing the above not~d nonionic surfactant as carrier, and dye, the resulting composition is essentially in the form of a gel w~ich can range in consistency from thin cream-like gels to heavy grease-type gels, depending particularly upon the proportion of ~ilica incorporated.
The resulting dye penetrant composition or gel of the invention avoids the above-noted problems previously encountered in employing dye penetrants on heated surfaces, in that the gel-type dye penetrants of the invention are resistant to liquefac-tion and decomposition and do not generate fumes when applied to surfaces heated to a temperature, e.g., above 100 F. In view of such heat stability, the dye penetrant composition when ap-plled to slanted or anyularly disposed heated surfacesl~
': . ': ' ' 0~5529 including overhead and vertical heated surfaces, o~ objects to - :
be nondestructively tested, does not drip, run off or puddle.
Moreover, the silica additive is not only heat resistant but ~ -is inert with respect to the other com~onents of the dye pene- :
trant composition, and the excess dye penetrant can be readily washed away, the compo~ition other than the inert silica, being biodegradable. of particular significance, the presence o~ the silica in the dye penetrant composition does not change the sen~itivity or brilliance of the dye indication of cracks and flaws which are obtained. ~:~
It was unexpected to find that the dye penetrant com~
po3ition of the invention containing silica is heat resistant ~ .
at tempe~tures up to about 300F for extended periocls of time, :.
whereas, the dye penetrant co~position of my above patent, and . .
containing particularly ~-methyl-2-pyrrolidone a~ vehi~le, is not heat re~istant and becomes powdery: and ineffective under such conditions, while the washability, sensitivity and 1uores-cent brilliance o~ the dye penetrant composition of the inven-tion on the other hand is not adversely a~fected by exposure to such elevated temperature use.
The above advantageous charaaterisitics of the dye penetrant composition of the invention are particularly valu-. able for inspection of parts or components o~ any equipmentwhich i~ under continuously heated conditions and cannot be shut down convenient}y, such as steam generators-:: and atomic reactors, or parts with thick cross sections, e.g., welds in shipbuilding, which would require a ................. ~.~............ ~
:. ' .':,' " ', ".
-7- :
1C~455Z~
considerable time for cooling before nondestructive test inspec-tion. Also, the invention composition can be employed on parts which are environmentally heated, such as by solar heating.
The nonionic biodegradable solvent or carrier employed essentially as the sole vehicle or carrier for the dye of the dye penetrant composition according to the invention can be alkylene oxide condensation products prepared by the reaction of an organic compound having a reactive hydrogen atom, such as an aliphatic alcohol, wikh ethylene oxide, propylene oxide, or mixtures thereof.
The biodegradable nonionic surfactant employed comprises alkoxy-lates of essentially ~inear primary of secondary aliphatic alcohols having alkyl chains of from 8 to 20 carbon atoms~ and an average of from 3 to 12 moles of an alkylene oxide of from 2 to 4 carbon atoms or mixture thereof, preferably, they are essentially linear primary, aliphatic oxyalkylated alcohols, generally in the form of mixtures thereof, wherein the primary aliphatic alcohols can have from 8 to 20 carbon atoms, preferably 10 to 1~ carbon atoms, and the oxyalkyl groups are ethylene oxide and propylene oxide, prefer- ~ -ably in the form of a mixture thereof.
One class of nonionic carriers within the broad c~ass of materials defined above is a cogeneric mixture of compounds represented by the formula:
R-O(A~H
wherein:
R is an essentially linear alkyl group having from 10 to 18 carbon atoms, with the provise that at least 70 :. ' ".
.' .''''~ ' .:
:
8 - ~-~ ` ~0455;~9 ~
weight percent of said compounds in said mixture have an R
of from 12 to 16 carbon atoms, and A is a mixture ~f oxy~
propylene and oxyethylene groups, said oxypropylene and ox~è~hylene groups being from 55% to 8~ of the total weight o~ the compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1, preferably 1.25:1 to 2.25:1.
Another preferred class o condensation products or oxyalkylated alcohols within th~ above definition are those wherein the aliphatic alcohols of the oxyalkylated alcohols, or R in the above formula, ranges from 12 to 18 carbon atoms, and the total number of ethylene oxide and propylene oxide groups in the mixture thereof, or designated A in the above formula, ranges ~rom about 4 to about 14.
The term "cogeneric mixture" as employed herein, de~ignates a series of closely related homologues obtained by condensing a plurality o~ oxide u~its, with an alcohol or a mixture thereof. As is known, when a mixture of this type ~is generated, various oxyalkylene chain lengths are obtained.
Alcohol3 which may be employed in the preparation of the products noted above are those e~sentially linear, primary, aliphatic alcohols having from 8 to 20 carbon atoms, pre~erably 10 to 18 carbon atoms. Mixtures of alcohols are usually pre-ferred since their use provide~ for a good balance of pro- ;
.
perties in the resulting products. Examples of alc~h~ls which are op¢rable include decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol,tetra-docyl alcohol, pentadecyl .
alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, ~9~
lO~SS;Z ~
hydrogenated tallow alcohol, and mixtures thereof. They may be naturally-derived such as from coconut oil or synthetically-derived such as from linear alkanes or linear olefins.
The above nonionic biodegradable surfactants employed as carrier or vehicle for the dye of the penetrant solution according to the invention, are prepared by condensing an alcohol or mixture of alcohols, as described above, with a mixture of ethylene oxide and propylene oxide, in the presence of an alkaline catalyst, such as potassium ~ydroxide. ~he oxide mixture may be added to the ~
alcohol in one continuous step or it may be added in sevexal steps.
The products thus produced possess random distribution of oxyethy-~ene and oxypropylene groups.
The nonionic surface active agents described above and their method of prepar~tion are disclosed in U.S. Patent No.
3,504,041. These surface active agents are believed to include, for example, that class of surfactants which are marketed as the "Plurafac" (trade mark) surfactants "RA-40" grades.
Another class of biodegradable liquid, water miscible oxy-alkylated alcohol condensation products within the above definition are those wherein the aliphatic alcohol, or R, is a straight chain alkyl group having from 8 to 20 carbon atoms, the number of ethy-lene oxide groups in the mixture thereof with propylene oxide, or A, ranges from 3.75 to 12.75, and the number of propylene oxide groups in such mixture ranges from 1.7 to 7.0, the oxyethylene to ~
oxypropylene ratio in such mixtures being from 1.8:1 to 2.2:1. -, Such cogeneric mixtures i ' 10 ~1~)4SS29 : ~
.
n be prepared in two steps, the first step being condensation of an alcohol mixture and ethylene oxide in the presence of an alkaline condensing agent or catalyst, to form an ethoxylated product, followed by condensing the resulting ethoxylated product with propylene oxide. There can be employed in such reaction a mixture of straight chain aliphatic alcohols having from 8 to 20 carbon atoms in the aliphatic chain. This cogeneric mixture of condensa-tion products and the method of their prepa~tion are disclosed in U.S. Patent No. 3,340,309. The nonionic oxyalkylated alcohols marketed as the "RA-20" grades of "Plurafac", are believed repre-sentative o the class of surface ackive agents disclosed in the latter patent.
Various other "Plurafac" grades which are marketed and are believed to be generally within the above-described classes of oxy-alkylated alcohol surfactants are those designated RA~43, A-24, A-~5, B-25,5, B-26 and D-25.
A class of particularly preferred nonionic biodegradable solvents or carriers which can be employed as substantially the sole vehicle for the dye of the dye penetrant compositions according to the present invention are ethoxylates of a mixture of linear secondary aliphatic alcohols, with the hydroxyl groups randomly distributed, the linear aliphatic hydrophobic portion of such alcohols being a mixture of alkyl chains aontaining in the range ~rom lO to 17 carbon atoms, preferably from ll to 15 carbon atoms, and containing an average of from 3 to 12 moles of ethylene oxide.
.~
' '~' '', : .
The above particularly preferred class o~ nonionic biodegradable surfactant employed as carrier for the dye penetrant of the invention is a mixture of. compounds which can be represented by the formula:
CH3-(CH2)n CH3 O~ (CH2-CH20~m-H
where n is in the range from 9 to 13, and m is an average o 3 to l2.
Although preferably each of the immediately above-defined surfactants is formed of a mixture of two or more linear alkyl hydrophobic chains ranging from Cll to C15 as noted below, the surfactant can contain a single such ahain formed from a ~ingle secondary aliphatic alcohol of the types described below. :: .
The linear alkyl hydrophobic portion of the above defined surfactant is a mixture of Cll to C15 linear alkyl chains, and can be derived from a mixture of Cll to C15 aliphatic secondary alcohols, for example the secondary undecyl, dodecyl, tridecyl, ~etradecyl and pentadecyl alcohols. ;;
The hydrophilic portion of the surfactant i5 a polyoxyethylene chain raddomly at~ached to any carbon atom of the linear alkyl hydrophobic ~hains, other than to the terminal carbon atoms ::-. .
thereof, through an ether linkage. Such hydrophilic p~ oxy- ;
ethylene chain is generally expressed in terms of an average number of moles of ethylene oxide. : ~
Illustrative examples of biodegradable nonionic .:
surf~ctants of the types defined in the ab~ve formula are :
those consisting of a mixture of ethoxylates ~f from 11 to : .
15 carbon atoms in the aliphatic hydrophobic chain, and which have an average of 3, 5, 7, 9 and 1~ moles of ethylene oxide, respectively as the hydrophil.
Materials corresponding to these fiv~e examples of biodegrad-able nonionic surfactants are marketed, resplsctively as:
Tergitol (trade mark) 15-S-3 " 15-S-5 " 16~S-7 " 15-S-9 " 1~-S-12 In each case of the Tergitol S series of surfactants listed above, the number to the left of the "S" indicates a hydrophobic aliphatic chain of from 11 to 15 carbon atoms derived from a mixture of alcohols on Cll to C15 backbone chains, and the number to the right of the "S" designates the average number of moles of ethylene oxide as the hydrophil. Thus for example, Tergitol 15-S-5 is a mixture of linear aliphatic alcohols in *he Cll to C15 range ethoxylated with an average of 5 moles of ethylene oxide~ All of these commercially marketed Tergitol S series of surfactants are water soluble except for Tergitol 15-S-3, which is essentially water insoluble. Mixtures o these materials can also be employed in providing the dye penetrant of the invention, such as a mixture of the above Tergitols 15-S-5 and 15~S~3; a mixture of 15-S-3 and 15-S-9; and a mixture of 15-S-5 and 15-S-9.
The above preferred class of nonionic biodegradable sur-faatants employed as carrier or vehicle for the dye of the . ~ ' ', .
"~r~ ', - 13 -- . , ~09!~552~
penetrant solution according to the invention, are prepared by reacting an alcohol or mixture of alcohols, as described above, with the desired proportion of ethylene oxide, in the presence of an alkaline catalyst, such as potassium hydroxide.
The ethylene oxide may be added to the alcohol or mixture of alcohols in one continuous step ox it may be added in several stepsO The products thus produced possess random distribu-tion of oxyethylene groups, as noted above.
Another process for preparing the above preferred nonionic surfactants in the form of ethoxylates of linear secondary aliphatic alcohols, is described in U. S. Patent No.
This invention relates to an improved non-dripping, heat resistant biodeyradable dye penetrallt composltion and method for non-destructively testing material specimens to locate and identify surface voids, cracks or defects. The invention is especially concerned with a novel dye penetrant composition having the above characteristics, and which can be applied to heated surfaces of an object without decomposi-tion or liquefaction, and without generating fumes, and which in addition has the properties of being readily water washable, and sensitive for disclosing a wide range of defective con-ditions in parts, employing as solvent or vehicle certain .
: ~ :
~ ..
~: :
~ :: : : :
4SSZ~
biadegradable nonionic surfactants in the form of certain oxy~
alkylated alcohols, and mixtures thereof; and to a method of utilizing such d~ penetrant composition for non-destru~-tive testing of parts, particularly parts heated to elevated temperature.
In known penetrant inspection methods for xapid location and evaluation of surface flaws or cracks in test bodies or parts, a dye penetrant composition, preferably con- ;
taining a fluorescent dye, and which will penetrate the open-ings of the surface cracks or flaw~ in the part, is applied to the surface of the test body, and the excess penetrant ~;
composition is removed from the surface of the body. A
developer composition may then be applied to the part surface, which acts as a wick and causes the liquid pcnetrant contain-ing the fluorescent dye, which was retained in the cracks or surface flaws, to be drawn up out of the surface defects by ¢apillary action. The part is then exposed to appropriate lighting conditions, such as invisible fluorescigenous light, and the location o~ the surfacs flaws is revealed by the emission of visible fluorescent light by the penetrant clye which was retained in the cracks or flaw~ after the penetrant composition wa~ removed from the sur~ace of the part.
For best efficiency, partic~larly for the detection . .
and location of minute surface cracks and flaws, as well as intermediate size and gross cracks, it is necessary that the ~ . . .
dye penetrant composltion have high sensiti~ity.
In addition, stability of the penetrant solution is essential without the necessity for carefully balancing the '!' ,.'~.'''., .. .: . ~ . . .. . ....
various liquid components of a dye penetrant solution in order to obtain efficient penetration of the solution into the cracks and flaws of a part, dye solubility, wetting action and washability control.
An additional criterion has recently developed also with respect to dye penetrant solutions and compositions. Generally, dye penetrant solutions presently being usecl and containing sol~
vents and wetting agents present a disposal problem in that they are substantially non-biodegradable, that i~;, they are very dif-ficult to decompose by bacteria in sewage disposal plants. Hence . ., :. .
the necessity for the development of dye penetrant solutions and compositions which are biodegradable, that is which employ dye solvents and carriers which are biodegradable, and are readily available despite the petrochemical shortage, has attained con-siderable importance.
Novel dye penetrants can be used which have improved washability and sensitivity characteristics, and which are biode-gradable, containing as the vehicle for the dye, certain biodegrad-able nonionic oxyalkylated alcbh~ls.
Further, penetrant inspection of hot surfaces of parts, e~pecially those of overhead and vertical orientation, present a particular problem. Conventional penetrants when employed under these conditions become extremely liquefied, produce obnoxious fumes, drip and change in sensitivity due to loss of volatiles. A conven-tional dye penetrant employed under these conditions and thinned by the action of heat creates a messy condition because it cannot be contained in prescribed . ., ~
~ - .
:
.. ~ ~, . .
10~S529 areas of parts or assemblies being inspected. ~ -In my Pahent No. 3,465,146 there is disclosed a dye ~
penetrant which comprises conventional liquid organic dye ~ -carriers or vehiole~ such as ~-methyl-2-pyrrolidone, and a thickening agent such as silica. However, although such composition is effective when applied to surfaces which are . - -at approximately ambient temperature, when applied to heated surfaces, e.g. surfaces heated at temperature in excess of ~
about 100 F, the composition dries and forms a powdery `~;
material and fails to perform effectively. In addition, the dye penetrant compositions of this patent are not biodegrad- -able.
Accordingly, an object of the present invention i8 the provision of a biodegradable heat resistant dye penetrant ,: .: ., composition which i~ a simple formulation and which does not ~: .. . .
require the use of mixtures of conventional solvents and wetting agent~, and which is foxmed of an essentially single or sole vehicle or carrier or the dye in the form of a bio-degradable nonionic surfactant, and which is heat stable, has excellent sensitivity and is essentially non-flammable and ; non-toxic. A particular object of the invention is to provide a dye penetrant composition of the above noted type, and which ~. ..-. .
in~orporates an additive which converts the dye penetrant composition to a gel-like consistency, permitting the dye .
pe~etrant composition to be applied to heated surfaces of objects disposed at~varying angles, without becoming lique~ied and dxipping, and without generating obnoxious fumes, substan-tially without afecting the biodegradability, penetrability :
: , .
', : ~ :
1C)455;Z9 or sensitivity of the dye penetrant. A still further object is the provision of procedure employing such novel heat stable biodegradable dye penetrant composition for inspection of cracks, flaws and metallurgical conditions in~tructural compo- -nents, particularly parts heated to elevated temperature, with-out dripping.
DESCRIPTION OF THE INVENTIO~
According to the present invention, it has been found that the above objects and advantages can be accomplished by an improved heat resistant and non-dripping dye penetrant, having good sensitivity for detection of cracks and defects in metal surfaces, and which is biodegradable, is provided by employing as a solvent or carrier for the dye, e.g., fluorescent dye, a biodegradable nonionic surfactant and incorporating a substan-tial proportion of silica (silicon dioxide), preferably in pow-dered form. Upon incorporation of the powdered silica into the dye penetrant containing the above not~d nonionic surfactant as carrier, and dye, the resulting composition is essentially in the form of a gel w~ich can range in consistency from thin cream-like gels to heavy grease-type gels, depending particularly upon the proportion of ~ilica incorporated.
The resulting dye penetrant composition or gel of the invention avoids the above-noted problems previously encountered in employing dye penetrants on heated surfaces, in that the gel-type dye penetrants of the invention are resistant to liquefac-tion and decomposition and do not generate fumes when applied to surfaces heated to a temperature, e.g., above 100 F. In view of such heat stability, the dye penetrant composition when ap-plled to slanted or anyularly disposed heated surfacesl~
': . ': ' ' 0~5529 including overhead and vertical heated surfaces, o~ objects to - :
be nondestructively tested, does not drip, run off or puddle.
Moreover, the silica additive is not only heat resistant but ~ -is inert with respect to the other com~onents of the dye pene- :
trant composition, and the excess dye penetrant can be readily washed away, the compo~ition other than the inert silica, being biodegradable. of particular significance, the presence o~ the silica in the dye penetrant composition does not change the sen~itivity or brilliance of the dye indication of cracks and flaws which are obtained. ~:~
It was unexpected to find that the dye penetrant com~
po3ition of the invention containing silica is heat resistant ~ .
at tempe~tures up to about 300F for extended periocls of time, :.
whereas, the dye penetrant co~position of my above patent, and . .
containing particularly ~-methyl-2-pyrrolidone a~ vehi~le, is not heat re~istant and becomes powdery: and ineffective under such conditions, while the washability, sensitivity and 1uores-cent brilliance o~ the dye penetrant composition of the inven-tion on the other hand is not adversely a~fected by exposure to such elevated temperature use.
The above advantageous charaaterisitics of the dye penetrant composition of the invention are particularly valu-. able for inspection of parts or components o~ any equipmentwhich i~ under continuously heated conditions and cannot be shut down convenient}y, such as steam generators-:: and atomic reactors, or parts with thick cross sections, e.g., welds in shipbuilding, which would require a ................. ~.~............ ~
:. ' .':,' " ', ".
-7- :
1C~455Z~
considerable time for cooling before nondestructive test inspec-tion. Also, the invention composition can be employed on parts which are environmentally heated, such as by solar heating.
The nonionic biodegradable solvent or carrier employed essentially as the sole vehicle or carrier for the dye of the dye penetrant composition according to the invention can be alkylene oxide condensation products prepared by the reaction of an organic compound having a reactive hydrogen atom, such as an aliphatic alcohol, wikh ethylene oxide, propylene oxide, or mixtures thereof.
The biodegradable nonionic surfactant employed comprises alkoxy-lates of essentially ~inear primary of secondary aliphatic alcohols having alkyl chains of from 8 to 20 carbon atoms~ and an average of from 3 to 12 moles of an alkylene oxide of from 2 to 4 carbon atoms or mixture thereof, preferably, they are essentially linear primary, aliphatic oxyalkylated alcohols, generally in the form of mixtures thereof, wherein the primary aliphatic alcohols can have from 8 to 20 carbon atoms, preferably 10 to 1~ carbon atoms, and the oxyalkyl groups are ethylene oxide and propylene oxide, prefer- ~ -ably in the form of a mixture thereof.
One class of nonionic carriers within the broad c~ass of materials defined above is a cogeneric mixture of compounds represented by the formula:
R-O(A~H
wherein:
R is an essentially linear alkyl group having from 10 to 18 carbon atoms, with the provise that at least 70 :. ' ".
.' .''''~ ' .:
:
8 - ~-~ ` ~0455;~9 ~
weight percent of said compounds in said mixture have an R
of from 12 to 16 carbon atoms, and A is a mixture ~f oxy~
propylene and oxyethylene groups, said oxypropylene and ox~è~hylene groups being from 55% to 8~ of the total weight o~ the compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1, preferably 1.25:1 to 2.25:1.
Another preferred class o condensation products or oxyalkylated alcohols within th~ above definition are those wherein the aliphatic alcohols of the oxyalkylated alcohols, or R in the above formula, ranges from 12 to 18 carbon atoms, and the total number of ethylene oxide and propylene oxide groups in the mixture thereof, or designated A in the above formula, ranges ~rom about 4 to about 14.
The term "cogeneric mixture" as employed herein, de~ignates a series of closely related homologues obtained by condensing a plurality o~ oxide u~its, with an alcohol or a mixture thereof. As is known, when a mixture of this type ~is generated, various oxyalkylene chain lengths are obtained.
Alcohol3 which may be employed in the preparation of the products noted above are those e~sentially linear, primary, aliphatic alcohols having from 8 to 20 carbon atoms, pre~erably 10 to 18 carbon atoms. Mixtures of alcohols are usually pre-ferred since their use provide~ for a good balance of pro- ;
.
perties in the resulting products. Examples of alc~h~ls which are op¢rable include decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol,tetra-docyl alcohol, pentadecyl .
alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, ~9~
lO~SS;Z ~
hydrogenated tallow alcohol, and mixtures thereof. They may be naturally-derived such as from coconut oil or synthetically-derived such as from linear alkanes or linear olefins.
The above nonionic biodegradable surfactants employed as carrier or vehicle for the dye of the penetrant solution according to the invention, are prepared by condensing an alcohol or mixture of alcohols, as described above, with a mixture of ethylene oxide and propylene oxide, in the presence of an alkaline catalyst, such as potassium ~ydroxide. ~he oxide mixture may be added to the ~
alcohol in one continuous step or it may be added in sevexal steps.
The products thus produced possess random distribution of oxyethy-~ene and oxypropylene groups.
The nonionic surface active agents described above and their method of prepar~tion are disclosed in U.S. Patent No.
3,504,041. These surface active agents are believed to include, for example, that class of surfactants which are marketed as the "Plurafac" (trade mark) surfactants "RA-40" grades.
Another class of biodegradable liquid, water miscible oxy-alkylated alcohol condensation products within the above definition are those wherein the aliphatic alcohol, or R, is a straight chain alkyl group having from 8 to 20 carbon atoms, the number of ethy-lene oxide groups in the mixture thereof with propylene oxide, or A, ranges from 3.75 to 12.75, and the number of propylene oxide groups in such mixture ranges from 1.7 to 7.0, the oxyethylene to ~
oxypropylene ratio in such mixtures being from 1.8:1 to 2.2:1. -, Such cogeneric mixtures i ' 10 ~1~)4SS29 : ~
.
n be prepared in two steps, the first step being condensation of an alcohol mixture and ethylene oxide in the presence of an alkaline condensing agent or catalyst, to form an ethoxylated product, followed by condensing the resulting ethoxylated product with propylene oxide. There can be employed in such reaction a mixture of straight chain aliphatic alcohols having from 8 to 20 carbon atoms in the aliphatic chain. This cogeneric mixture of condensa-tion products and the method of their prepa~tion are disclosed in U.S. Patent No. 3,340,309. The nonionic oxyalkylated alcohols marketed as the "RA-20" grades of "Plurafac", are believed repre-sentative o the class of surface ackive agents disclosed in the latter patent.
Various other "Plurafac" grades which are marketed and are believed to be generally within the above-described classes of oxy-alkylated alcohol surfactants are those designated RA~43, A-24, A-~5, B-25,5, B-26 and D-25.
A class of particularly preferred nonionic biodegradable solvents or carriers which can be employed as substantially the sole vehicle for the dye of the dye penetrant compositions according to the present invention are ethoxylates of a mixture of linear secondary aliphatic alcohols, with the hydroxyl groups randomly distributed, the linear aliphatic hydrophobic portion of such alcohols being a mixture of alkyl chains aontaining in the range ~rom lO to 17 carbon atoms, preferably from ll to 15 carbon atoms, and containing an average of from 3 to 12 moles of ethylene oxide.
.~
' '~' '', : .
The above particularly preferred class o~ nonionic biodegradable surfactant employed as carrier for the dye penetrant of the invention is a mixture of. compounds which can be represented by the formula:
CH3-(CH2)n CH3 O~ (CH2-CH20~m-H
where n is in the range from 9 to 13, and m is an average o 3 to l2.
Although preferably each of the immediately above-defined surfactants is formed of a mixture of two or more linear alkyl hydrophobic chains ranging from Cll to C15 as noted below, the surfactant can contain a single such ahain formed from a ~ingle secondary aliphatic alcohol of the types described below. :: .
The linear alkyl hydrophobic portion of the above defined surfactant is a mixture of Cll to C15 linear alkyl chains, and can be derived from a mixture of Cll to C15 aliphatic secondary alcohols, for example the secondary undecyl, dodecyl, tridecyl, ~etradecyl and pentadecyl alcohols. ;;
The hydrophilic portion of the surfactant i5 a polyoxyethylene chain raddomly at~ached to any carbon atom of the linear alkyl hydrophobic ~hains, other than to the terminal carbon atoms ::-. .
thereof, through an ether linkage. Such hydrophilic p~ oxy- ;
ethylene chain is generally expressed in terms of an average number of moles of ethylene oxide. : ~
Illustrative examples of biodegradable nonionic .:
surf~ctants of the types defined in the ab~ve formula are :
those consisting of a mixture of ethoxylates ~f from 11 to : .
15 carbon atoms in the aliphatic hydrophobic chain, and which have an average of 3, 5, 7, 9 and 1~ moles of ethylene oxide, respectively as the hydrophil.
Materials corresponding to these fiv~e examples of biodegrad-able nonionic surfactants are marketed, resplsctively as:
Tergitol (trade mark) 15-S-3 " 15-S-5 " 16~S-7 " 15-S-9 " 1~-S-12 In each case of the Tergitol S series of surfactants listed above, the number to the left of the "S" indicates a hydrophobic aliphatic chain of from 11 to 15 carbon atoms derived from a mixture of alcohols on Cll to C15 backbone chains, and the number to the right of the "S" designates the average number of moles of ethylene oxide as the hydrophil. Thus for example, Tergitol 15-S-5 is a mixture of linear aliphatic alcohols in *he Cll to C15 range ethoxylated with an average of 5 moles of ethylene oxide~ All of these commercially marketed Tergitol S series of surfactants are water soluble except for Tergitol 15-S-3, which is essentially water insoluble. Mixtures o these materials can also be employed in providing the dye penetrant of the invention, such as a mixture of the above Tergitols 15-S-5 and 15~S~3; a mixture of 15-S-3 and 15-S-9; and a mixture of 15-S-5 and 15-S-9.
The above preferred class of nonionic biodegradable sur-faatants employed as carrier or vehicle for the dye of the . ~ ' ', .
"~r~ ', - 13 -- . , ~09!~552~
penetrant solution according to the invention, are prepared by reacting an alcohol or mixture of alcohols, as described above, with the desired proportion of ethylene oxide, in the presence of an alkaline catalyst, such as potassium hydroxide.
The ethylene oxide may be added to the alcohol or mixture of alcohols in one continuous step ox it may be added in several stepsO The products thus produced possess random distribu-tion of oxyethylene groups, as noted above.
Another process for preparing the above preferred nonionic surfactants in the form of ethoxylates of linear secondary aliphatic alcohols, is described in U. S. Patent No.
2,870,220.
Any suitable dye generally employed in dye penetrant compositions can be incorporated into the nonionic oxyalky-lated alcohol surfactants described above for producing ~he dye penetrant compo~ tions employed in the invention process.
Preerably, however, a fluorescent dye is employed for this -~
purpose. The oxyalkylated surfactant vehicle for the dye is compatible therewith and has the ability to dissolve either small or relatively large amounts of the dye and to hold a high concentration of dye in solution while providing good xesolution and clarity of the dye trace in the cracks and .
~laws.
As previously noted, the dye penetrant solution employed according to the invention preferably contains a fluorescent dy~. Various types of fluorescent dyes can be employed including for example the dye marketed as Fluorol 7GA as well as other fluorescent dyes such as those marketed as Calco1uor Yellow, Azosol Brilliant Yellow 6GF; Rhodanine B~
-14- :
.. .. :
~.~45S2~
Rhodanine 6 GD~, Calcofluor White RW, Blancophor White AW, Auramine and Eosine G, and water soluble 1uorescent dyes such as Blancophor FFG.
The dye penetrant composition employed according to the invention alternatively can contain non-flu4re~cent or daylight type dyes such as azo type dyes, e.g., xylenaezo- ~ :
beta-naphthol, Mefford ~o. 322 dye, believed to be o-toluene-azoxyleneazo-beta-naphthol, and the azo dyes marketed as Oil Red "o" and Sudan Red. These dyes conveniently can be employed where d~ylight or white light is only available, and particularly where the surface of the body to be detected contains relatively gross cracks. ~owever, it is pre~erred to employ fluorescent dyes having greater sensitivity or : :
detectability as result of the high contrast o~tained by the ~ :
fluorescent indications, The amount of dye which is incorporated into the oxyalkylated alcohol surfactant or carrier to produce the dye penetrant composition of the invention, can range from about Ool to 15, preferably about 0.5 to about 10, parts of the dye, :
or mixtures thereof, per 100 parts of the oxyalkylated alcohol sur~actant, by weight. In preparing the dye penetrant composi-tion employed according to the invention, the dye is simply added to the ~xyalkylated alcohol carrier, in the desired proportion. The resulting dye penetrant composition has both high and low temperature stability.
Although Tergitol 15-S-3 is essentially water insol-uble and is usually employed in combination with the other mem-bers o~ the Tergîtol S series noted above, such as Terg:itol 15-S-5, dye penetrant compositions according to the invention ~15- :
~ss~9 containing Tergitol 15-S-3 alone, can be employed. However, Tergitol 15-S-3 has its greatest utility for production of dye penetrants having high sensitivity according to the invention, when employed in combination with the other water washable and water soluble Tergitols such as Tergitol 15-S-5 andl Tergitol 15-S-9.
Also, particularly effective dye penetrants aLre provided according to the invention employing a combination or mixture of the above Tergitols 15-S-5 and 15-S-9 and to which there can be added optionally Tergitol 15-S-3.
The silica additive incorporated in the dye penetrant composition for rendering such composition heat resistant and non-dripping, is preferably in fine powder form and of particle size ranging from about 0.007 to about 0.050 micron (about 70 to about 500 Angstroms), and is an extremely fluffy, snow-white powder of ~xtremely low bulk density. A commercially available form of this component is marketed as Cab-O-Sil (trade mark) M-5 by Cabot Corporation. The Cab-O-Sil has an enormous external area, one gram of Cab-O-Sil M-5 having about 400 square meters of surface area.
Cab-O-Sil M-5 is a submicroscopic fire-dry fumed silica cl1ferent in structure from precipitated silicas or silica gels, with a maximum density of 2.3 lbs./cu.ft.
The silica th~s incorporated into the dye penetrant hereof i3 capable of conferring thickening properties on the liquid dye penetrant without increasing the viscosity thereof. The ~ormation of the resulting gel does not inhibit the pene~rability or sensi-tivity of the gelled penetxant, but only limits its ability to flow over the surface to which it is ::: ~ .:
.~ :
" ~:
: ' . ' , . .
4552~
applied. Thus, the silica in the gel functions merely to entrap the penetrant in a multitude of sponges formed by the silica particles, but the penetrant itself remains liquid and ~uickly spreads into any surface defect with which the dye penetrant gel comes in contact in the same manner that a sponge filled with water wets a surace~ The silica addi-tive however is chemically stable and completely inert with respect to both the dye and the oxyalkylated nonionic surfac-tant vehicle of the penetrant. Thust the liquid ~ehicle of ;
the penetrant remains in liquid ~orm and its penetrability ~
and sensitivity are not affected by addition o the silica ~;
additive.
As previously noted, by addition of the s:ilica, theconsistency of the previously highly mobile liquid dye pene-trant changes to a gel-like appearance with the additive holding the liquid penetrant in the location where it i5 applied, preventing the tendency of the liquid to drip ox flow over a vertical or slanted surface, while the penatrant itself remains liquid and spreads ~uickly into any surface defect with which the dye penetrant gel comes into contactp The amount of silica added to the dye penetrant can vary widely, but generally the silica i8 a substantial portion of the resulting composition, the amount employed beiny suf-~icient to convert the dye penetrant composition into a gel~ -Generally~ there can be employed about 1 to about 8 parts of silica per 1 part, by volume, vf the sum of the other com-ponents of the dye penetrant, namely the oxyalkylat~d nonionic surfactant and dye. Preferably about 1 to about 6 parts o sil-ica, and most desirably about 3 to about 6 parts of s~ilica, to ~. - . .
` 1~45SZ9 : ~
1 part, by volume, of the sum o the remaining dye penetrant components, is utilized. The above general and preferred volumetric ranges correspond approximately to a general range of about 4 to about 320 and a preferred range of about 4 to about 25, paxts of silica, to 100 parts by weight, of the sum of the surfactant and dye. When slmaller proportions of silica are employed within the above noted ranges, the resulting gels can have a thin cream-like consistency, and when larger propo~tions of silica are employed within the above noted ranges, the resulting gels can have a heavy grease-type consistency. The gels produced according to the invention are generally clear and translucent. Regardless of the consî~tency of such gels, it has been found that they are sufficiently adhesive to prevent runoff of the dye pene-trant when applied to slanted, vertical or overhead surfaces.
Typical liquid dye penetrant compositions to which the silica additive can be added according to the invention are as follows:
' Liquid Compositions (Parts by Wei~ht) COMPONENTS A B C D E F (3 H
.. . ., . . _ Tergitol 15-S-3 -~ -- 25 --Tergitol 15-S-5100 -- 75 -- 75 -- 75 75 Tergitol 15-S-9 -- -- 25 -- -- 100 25 25 Pluravac A-24 -- 100 -- -- -- --Plurafac RA-43 -- -- -- 100 -- --Calcofluor White RW 5.0 5.0 5.0 5.0 2.5 2.5 2..5 1.25 Fluorol 7 G A 1.5 1.5 1.5 1.5- 0.75 0.75 0.75 O 37$
Illustratlve examples of the dye penetrant gel com-position~ oE the invention incorporating varying proportions, o the fumed silica, cab-O-sil M-5, into the typical dye pene-trant compositions A-H of Table 1 above, are set Eorth in Table 2 below.
DYe Penetrant Gel ComPositions (Parts bY Volume COMPONENTS I II III IV V VI VII VIII IX
. . . _ Cab-O-Sil M-5, 5 5 4 3 2 1 6 5 7 B
C
D
E
F
G
H
~55;2~
Where a developer composition is employed, any one of the three general types of developer compositions, namely dry powder, wet aqueous (water-base) and wet non-aqueous (volatile solvent base) developer compositions can be employed. In each case~ the developer composition contains a light colored powder, forming a coating which contrasts with the color of the dye in the penetrant and which acts as a wick or blotter, and causes liquid penetrant con-taining the dye, e.g. fluorescent dye, which was retained in the cracks or surface flaws, to be drawn up out of the surface defects by capillary action and to "bleed" thxough the powder. Preferred developer compositions for use in conjunction with the dye pene-trant composition according to the invention, are those described in my Patent No. 3,803,051, which is a dry powder developer con-taining fumed alumina, fumed silica, ~umed titanium dioxide and talc, and in my Patent No. 3,748,469, and which is a wet nonaqueous developer composition consisting essentially o isopropyl alcohol, talc and glycol monobutyl ether.
The dye penetrant composition employed in the invention process, employing the above biodegradable nonionic oxyalkylated alcohol surfactants can be tailored to have varying degrees of sensitivity for detection of the smallest micro-cracks to gross cracks in a part surface by generally varying khe amount of dye incorporated and also by selecting particular surfactants or combinations thereof.
In the method for detecting crac~s and flaws in the sur~
face of an object employing khe dye penetrant compositions of the invention, such dye penetrant in gel form is applied , ~ ~ - 20 -.....
1~ 529 to the part surface in any suitable manner, as for example, by brushing. After application of the dye penetrant gel to the surface of the test part, the excess dye penetrant com-position is readily removed from the object: surface by water washing, e.g. by application of a water ~pray or sprayed mix-ture of air and water. In such procedure when the part sur-face is at high temperature of the order of about 200-300 F, some of the water wash i9 converted to steam, which is bene-ficial. The dye penetrant gel composition hereof, such as those containing the above noted Plurafacs and particularly those containing the abo~e Tergitols 15-S-5 to 15-S-9, gen-erally have axcellent washability without removing dye pene-trant from the cracks and de~acts on the part surface.
If desired~ a developer composition of the types ~ `~
noted above can then be applied to the part surface followed by removal of excess developer, as by means of an air blast.
The part is then viewed under suitable lighting conditions, employing black light or fluorescent illumination when the dye penetrant contains a fluorescent dye.
Illustrative example~ of practice of the invention are set forth below.
Dye penetrant composition I of Table 2 above was prepared by mixing 5 parts o~ Cab-0-Sil M-5 to 1 part by ~ -volume of the liquid dye penetrant composition A of Table 1.
The resulting formulation was a heavy grease-type gel.
A test panel of 2014 aluminum ~ontaining microcracks uniformly distributed over the panel was divided by a groove 9155Z~I
into two equal test areas for test comparison purposes. The fluorescent dye penetrant gel composition I prepared as noted above was applied as by brushing to one half of the surface of the test panel which was previously heated to about 300 F
for a period of 3 hours. The excess dye penetrant gel com position on the test panel was removed by an air-water spray applied over the coating, causing almost instantaneous washing away of the dye penetrant gel from the surface of the panel without dislodging liquid dye penetrant from the surface cracks and thus entrapping the penetrant therein. The part was then dried by an air blast.
The procedure above was repeated, but applying the liquid dye penetrant composi~ion A of Table 1 above containing no Bilica~ to the other half of the test panel surface, ollowed by application of a water wash under the same conditio~ noted above for removal of excess dye penetrant, and finally followed by drying with an air blast.
The dye penetrant li~uid removed from the part sur-face in each of the a~ove procedures was biodegradable.
Inspection o~ the two penetrant treated surface~ of the test panel under ultraviolet or fluorescent light, revealed ~luorescent indications from numerou~ readily defined micro-cracks therein, the fluoresc~nt indications on both sides of the te~t panel being in substantially equivalent concentration, with substantial1y the same brightness and sensitivity or optical intenæity on both sides of the test panel~
This example shows that the silica containing dye :: .
penetrant composition of ths invention) following removal o excess dye penetrant gel, has esaentially the same ~;ensitivity .. ........
~55~Zg or ability to disclose cracks and defects in a part surface, and has the same biodegradability a~ in the case of the dye penetrant compoæition free of silica.
The gel composition I and II of ~rable 2 above, each conta~ning 5 parts of Cab-0-Sil M-5, to l part of the liquid dye penetrant compositions ~ and B, respecltively of Table l above, were ~ormulated, both being heavy grease-type ge].s which were clear and tranælucent.
Both of these gel ~enetrants were applied to t:est panels of chromium-plated bra~s containing minute cracks o the order of 0.00002 to 0.0001 inch in width, closely distri~
buted over their entire surfaces.
The gel compositions I and II each were app}ied by : ;
brushing to a ~eries of test panels o the above type, 5uch test panel~ being placed in various positions including slanted and vertical positions in a heated air circulating type oven.
The te~b were conducted at various temperature~ and time cycles ranging from 100F for 3 hours to 300F for 3 hours.
It was noted that the gel compositions remained on the areas of the test panels to which the compositions were applied, without any dripping or runoff, and no fumes were generated during the period that the gel~ were on the panel~, The test panels wère then sprayed with clean water or wiped with clean water-soaked rags to remove surface excess ponetrant, ~ollowed by air blasting for drying.
The tes~ panels were then immersed in a powder developer ha~ing the following composition, accordins t:o my ` ` ~IL~45S29 above Patent- No. 3,083,051.
COMPONEl~TS PERCE~T BY WEIGHT
Talc 52 Alumina 35 ;
Silica :
Excess developer composition w~s then carefully -removed rom the surfaces of the test paneLs by means of a gentle air blast.
The p~nels were then placed under black light (Fluorescent~ illumination and viewed. It was observed that the surfacq o~ all panels to which the above gel compositions I and II were applied, disclosed fluorescent indications from numerous readily defined microcracks therein, such fluorescent indicationQ being sharp and brilliant and revealing all de~
fectivQ conditions on the ~urface of the te~t panels.
The results of these tests showed the two gel pene-trant ~ormulations I and II each containing respectively ~ergitol nonionic 15-S-5 and Plura~ac A-24 nonionic sur~ac-20 tants, and the umed silica, to be highly heat resistant,non-migrating, non-lique~ying ~ormulations, and perorming effeatively under the drastic heated environment employed in the te~ts.
. : . ...:
~X~M LE 3 ~he grease-type d~e pene~rant composition of above Patent 3,465,l46 corresponding to composition I above, but contaLning ~-methyl-2-pyrrolidone as liquid vehicle for the - .
'' "
' ~Q~SSZ9~
dye instead of Tergitol 15-S-5, was tested by application to test panels of the type employed in Example 2 and heated under the same temperature conditions as :in Example 2.
After the period of heating, it was noted that the initially grease-like penetrant compositions applied to the surface of such panels had dried out and formed a powdery material.
Such powdery material was removed from the panel surfaces, a developer applied as in Example 2, and following removal of such developer the panels were viewed under fluor-escent light. It was found that unsatisfactory results were obtained, which did not provide the sensitivity, concentration and brilliance of the fluorescent indications which were observed on the test panels according to the procedure of Example 2 employing the gel compositionsI and II above.
Test~ ~ere carried out ~ollowing the procedure of Exampla 2 above, but employing test compositionæcorrespond-ing to compositions I and II above, wherein the proportion of Cab-0-Sil M-5 varied from 1 to 4 parts, to 1 part of the re-spective dye penetrant liquids A and B. ~he formulations thus produced ranged from thin cream-like gels employing the smaller proportions of the silica, to heavy grease-type gels when employing the higher proportions of silica O the g~ls in each case being essentially clear and translucent.
As in the case of Example 2, the gelled pen~etrants remained on the surface of the variously positioned and heated panels without dripping, runoff or pud~ling.
~!LV45S~9 Following removal of the excess dye p~netrant from the surface of the test panels, the remaining liquid dye :~
penetrants thus removed were biodegradableO :
In all cases the dye penetrant compo~ition performed :
excellently with bright fluorescent indications of the micro-crack~ obtained.
. .,: . .
The dye penetrant gel compositions of the invention are particularly applicable for use in detecting cracks, defects and metallurgical conditions in assemblies and parts which have been heat txeated and are still hot, recently welded assemblies and parts, aircraft stationed in hot cli- :
mates, rocket engines which are ~till hot, atomlc reactors : ~:
which require penetrant inspection while in ex~emely heated condition, and geothermal pre~sure ve3sels and piping.
From the foregoing, it i~ seen that the invantion provides a highly effective substantially biodegradable water washable dye penetrant composition in the form of a gel, which is heat resistant, nonflammable, and non~toxic, and which can be applied effectively to heated surfaces of parts positioned at various angle~, without runvE~ or dripping, and which can be readily removed rom a part surface by conventional wash ing. The dye penetrant gels of the invention contain as essential components a single carrier for the dye, which i~
preferably fluorescent, in the form of certain biodegradable oxyalkylated alcohols, and 8 substantial or major proportion of a ilica9 preerably fumed silica. Followîng removal o~
exce~s gel penetrant ~rom the surface of ~he parts and fur-ther processing of the part surfaces in the conventional ~ '"
' :''' ' ' .. . . . . . . . ~:
~5529 manner for viewing under ~uitable, e.g. fluorescent, light-ing conditions, fluorescent indicatio~ of high brilliance, definition and resolution of the dye traces from cracks and flaws in the part surfaces are obtainable, equivalent in this respect to the results obtained employing the same dye penetrant but in the absence of the silica.
Since various changes and modifications of the invention will occur to and can be made readily by those skilled in the art without departing from the invention con- -:
cept, the invention is not to be taken as limited except by the scope of the appended claims.
Any suitable dye generally employed in dye penetrant compositions can be incorporated into the nonionic oxyalky-lated alcohol surfactants described above for producing ~he dye penetrant compo~ tions employed in the invention process.
Preerably, however, a fluorescent dye is employed for this -~
purpose. The oxyalkylated surfactant vehicle for the dye is compatible therewith and has the ability to dissolve either small or relatively large amounts of the dye and to hold a high concentration of dye in solution while providing good xesolution and clarity of the dye trace in the cracks and .
~laws.
As previously noted, the dye penetrant solution employed according to the invention preferably contains a fluorescent dy~. Various types of fluorescent dyes can be employed including for example the dye marketed as Fluorol 7GA as well as other fluorescent dyes such as those marketed as Calco1uor Yellow, Azosol Brilliant Yellow 6GF; Rhodanine B~
-14- :
.. .. :
~.~45S2~
Rhodanine 6 GD~, Calcofluor White RW, Blancophor White AW, Auramine and Eosine G, and water soluble 1uorescent dyes such as Blancophor FFG.
The dye penetrant composition employed according to the invention alternatively can contain non-flu4re~cent or daylight type dyes such as azo type dyes, e.g., xylenaezo- ~ :
beta-naphthol, Mefford ~o. 322 dye, believed to be o-toluene-azoxyleneazo-beta-naphthol, and the azo dyes marketed as Oil Red "o" and Sudan Red. These dyes conveniently can be employed where d~ylight or white light is only available, and particularly where the surface of the body to be detected contains relatively gross cracks. ~owever, it is pre~erred to employ fluorescent dyes having greater sensitivity or : :
detectability as result of the high contrast o~tained by the ~ :
fluorescent indications, The amount of dye which is incorporated into the oxyalkylated alcohol surfactant or carrier to produce the dye penetrant composition of the invention, can range from about Ool to 15, preferably about 0.5 to about 10, parts of the dye, :
or mixtures thereof, per 100 parts of the oxyalkylated alcohol sur~actant, by weight. In preparing the dye penetrant composi-tion employed according to the invention, the dye is simply added to the ~xyalkylated alcohol carrier, in the desired proportion. The resulting dye penetrant composition has both high and low temperature stability.
Although Tergitol 15-S-3 is essentially water insol-uble and is usually employed in combination with the other mem-bers o~ the Tergîtol S series noted above, such as Terg:itol 15-S-5, dye penetrant compositions according to the invention ~15- :
~ss~9 containing Tergitol 15-S-3 alone, can be employed. However, Tergitol 15-S-3 has its greatest utility for production of dye penetrants having high sensitivity according to the invention, when employed in combination with the other water washable and water soluble Tergitols such as Tergitol 15-S-5 andl Tergitol 15-S-9.
Also, particularly effective dye penetrants aLre provided according to the invention employing a combination or mixture of the above Tergitols 15-S-5 and 15-S-9 and to which there can be added optionally Tergitol 15-S-3.
The silica additive incorporated in the dye penetrant composition for rendering such composition heat resistant and non-dripping, is preferably in fine powder form and of particle size ranging from about 0.007 to about 0.050 micron (about 70 to about 500 Angstroms), and is an extremely fluffy, snow-white powder of ~xtremely low bulk density. A commercially available form of this component is marketed as Cab-O-Sil (trade mark) M-5 by Cabot Corporation. The Cab-O-Sil has an enormous external area, one gram of Cab-O-Sil M-5 having about 400 square meters of surface area.
Cab-O-Sil M-5 is a submicroscopic fire-dry fumed silica cl1ferent in structure from precipitated silicas or silica gels, with a maximum density of 2.3 lbs./cu.ft.
The silica th~s incorporated into the dye penetrant hereof i3 capable of conferring thickening properties on the liquid dye penetrant without increasing the viscosity thereof. The ~ormation of the resulting gel does not inhibit the pene~rability or sensi-tivity of the gelled penetxant, but only limits its ability to flow over the surface to which it is ::: ~ .:
.~ :
" ~:
: ' . ' , . .
4552~
applied. Thus, the silica in the gel functions merely to entrap the penetrant in a multitude of sponges formed by the silica particles, but the penetrant itself remains liquid and ~uickly spreads into any surface defect with which the dye penetrant gel comes in contact in the same manner that a sponge filled with water wets a surace~ The silica addi-tive however is chemically stable and completely inert with respect to both the dye and the oxyalkylated nonionic surfac-tant vehicle of the penetrant. Thust the liquid ~ehicle of ;
the penetrant remains in liquid ~orm and its penetrability ~
and sensitivity are not affected by addition o the silica ~;
additive.
As previously noted, by addition of the s:ilica, theconsistency of the previously highly mobile liquid dye pene-trant changes to a gel-like appearance with the additive holding the liquid penetrant in the location where it i5 applied, preventing the tendency of the liquid to drip ox flow over a vertical or slanted surface, while the penatrant itself remains liquid and spreads ~uickly into any surface defect with which the dye penetrant gel comes into contactp The amount of silica added to the dye penetrant can vary widely, but generally the silica i8 a substantial portion of the resulting composition, the amount employed beiny suf-~icient to convert the dye penetrant composition into a gel~ -Generally~ there can be employed about 1 to about 8 parts of silica per 1 part, by volume, vf the sum of the other com-ponents of the dye penetrant, namely the oxyalkylat~d nonionic surfactant and dye. Preferably about 1 to about 6 parts o sil-ica, and most desirably about 3 to about 6 parts of s~ilica, to ~. - . .
` 1~45SZ9 : ~
1 part, by volume, of the sum o the remaining dye penetrant components, is utilized. The above general and preferred volumetric ranges correspond approximately to a general range of about 4 to about 320 and a preferred range of about 4 to about 25, paxts of silica, to 100 parts by weight, of the sum of the surfactant and dye. When slmaller proportions of silica are employed within the above noted ranges, the resulting gels can have a thin cream-like consistency, and when larger propo~tions of silica are employed within the above noted ranges, the resulting gels can have a heavy grease-type consistency. The gels produced according to the invention are generally clear and translucent. Regardless of the consî~tency of such gels, it has been found that they are sufficiently adhesive to prevent runoff of the dye pene-trant when applied to slanted, vertical or overhead surfaces.
Typical liquid dye penetrant compositions to which the silica additive can be added according to the invention are as follows:
' Liquid Compositions (Parts by Wei~ht) COMPONENTS A B C D E F (3 H
.. . ., . . _ Tergitol 15-S-3 -~ -- 25 --Tergitol 15-S-5100 -- 75 -- 75 -- 75 75 Tergitol 15-S-9 -- -- 25 -- -- 100 25 25 Pluravac A-24 -- 100 -- -- -- --Plurafac RA-43 -- -- -- 100 -- --Calcofluor White RW 5.0 5.0 5.0 5.0 2.5 2.5 2..5 1.25 Fluorol 7 G A 1.5 1.5 1.5 1.5- 0.75 0.75 0.75 O 37$
Illustratlve examples of the dye penetrant gel com-position~ oE the invention incorporating varying proportions, o the fumed silica, cab-O-sil M-5, into the typical dye pene-trant compositions A-H of Table 1 above, are set Eorth in Table 2 below.
DYe Penetrant Gel ComPositions (Parts bY Volume COMPONENTS I II III IV V VI VII VIII IX
. . . _ Cab-O-Sil M-5, 5 5 4 3 2 1 6 5 7 B
C
D
E
F
G
H
~55;2~
Where a developer composition is employed, any one of the three general types of developer compositions, namely dry powder, wet aqueous (water-base) and wet non-aqueous (volatile solvent base) developer compositions can be employed. In each case~ the developer composition contains a light colored powder, forming a coating which contrasts with the color of the dye in the penetrant and which acts as a wick or blotter, and causes liquid penetrant con-taining the dye, e.g. fluorescent dye, which was retained in the cracks or surface flaws, to be drawn up out of the surface defects by capillary action and to "bleed" thxough the powder. Preferred developer compositions for use in conjunction with the dye pene-trant composition according to the invention, are those described in my Patent No. 3,803,051, which is a dry powder developer con-taining fumed alumina, fumed silica, ~umed titanium dioxide and talc, and in my Patent No. 3,748,469, and which is a wet nonaqueous developer composition consisting essentially o isopropyl alcohol, talc and glycol monobutyl ether.
The dye penetrant composition employed in the invention process, employing the above biodegradable nonionic oxyalkylated alcohol surfactants can be tailored to have varying degrees of sensitivity for detection of the smallest micro-cracks to gross cracks in a part surface by generally varying khe amount of dye incorporated and also by selecting particular surfactants or combinations thereof.
In the method for detecting crac~s and flaws in the sur~
face of an object employing khe dye penetrant compositions of the invention, such dye penetrant in gel form is applied , ~ ~ - 20 -.....
1~ 529 to the part surface in any suitable manner, as for example, by brushing. After application of the dye penetrant gel to the surface of the test part, the excess dye penetrant com-position is readily removed from the object: surface by water washing, e.g. by application of a water ~pray or sprayed mix-ture of air and water. In such procedure when the part sur-face is at high temperature of the order of about 200-300 F, some of the water wash i9 converted to steam, which is bene-ficial. The dye penetrant gel composition hereof, such as those containing the above noted Plurafacs and particularly those containing the abo~e Tergitols 15-S-5 to 15-S-9, gen-erally have axcellent washability without removing dye pene-trant from the cracks and de~acts on the part surface.
If desired~ a developer composition of the types ~ `~
noted above can then be applied to the part surface followed by removal of excess developer, as by means of an air blast.
The part is then viewed under suitable lighting conditions, employing black light or fluorescent illumination when the dye penetrant contains a fluorescent dye.
Illustrative example~ of practice of the invention are set forth below.
Dye penetrant composition I of Table 2 above was prepared by mixing 5 parts o~ Cab-0-Sil M-5 to 1 part by ~ -volume of the liquid dye penetrant composition A of Table 1.
The resulting formulation was a heavy grease-type gel.
A test panel of 2014 aluminum ~ontaining microcracks uniformly distributed over the panel was divided by a groove 9155Z~I
into two equal test areas for test comparison purposes. The fluorescent dye penetrant gel composition I prepared as noted above was applied as by brushing to one half of the surface of the test panel which was previously heated to about 300 F
for a period of 3 hours. The excess dye penetrant gel com position on the test panel was removed by an air-water spray applied over the coating, causing almost instantaneous washing away of the dye penetrant gel from the surface of the panel without dislodging liquid dye penetrant from the surface cracks and thus entrapping the penetrant therein. The part was then dried by an air blast.
The procedure above was repeated, but applying the liquid dye penetrant composi~ion A of Table 1 above containing no Bilica~ to the other half of the test panel surface, ollowed by application of a water wash under the same conditio~ noted above for removal of excess dye penetrant, and finally followed by drying with an air blast.
The dye penetrant li~uid removed from the part sur-face in each of the a~ove procedures was biodegradable.
Inspection o~ the two penetrant treated surface~ of the test panel under ultraviolet or fluorescent light, revealed ~luorescent indications from numerou~ readily defined micro-cracks therein, the fluoresc~nt indications on both sides of the te~t panel being in substantially equivalent concentration, with substantial1y the same brightness and sensitivity or optical intenæity on both sides of the test panel~
This example shows that the silica containing dye :: .
penetrant composition of ths invention) following removal o excess dye penetrant gel, has esaentially the same ~;ensitivity .. ........
~55~Zg or ability to disclose cracks and defects in a part surface, and has the same biodegradability a~ in the case of the dye penetrant compoæition free of silica.
The gel composition I and II of ~rable 2 above, each conta~ning 5 parts of Cab-0-Sil M-5, to l part of the liquid dye penetrant compositions ~ and B, respecltively of Table l above, were ~ormulated, both being heavy grease-type ge].s which were clear and tranælucent.
Both of these gel ~enetrants were applied to t:est panels of chromium-plated bra~s containing minute cracks o the order of 0.00002 to 0.0001 inch in width, closely distri~
buted over their entire surfaces.
The gel compositions I and II each were app}ied by : ;
brushing to a ~eries of test panels o the above type, 5uch test panel~ being placed in various positions including slanted and vertical positions in a heated air circulating type oven.
The te~b were conducted at various temperature~ and time cycles ranging from 100F for 3 hours to 300F for 3 hours.
It was noted that the gel compositions remained on the areas of the test panels to which the compositions were applied, without any dripping or runoff, and no fumes were generated during the period that the gel~ were on the panel~, The test panels wère then sprayed with clean water or wiped with clean water-soaked rags to remove surface excess ponetrant, ~ollowed by air blasting for drying.
The tes~ panels were then immersed in a powder developer ha~ing the following composition, accordins t:o my ` ` ~IL~45S29 above Patent- No. 3,083,051.
COMPONEl~TS PERCE~T BY WEIGHT
Talc 52 Alumina 35 ;
Silica :
Excess developer composition w~s then carefully -removed rom the surfaces of the test paneLs by means of a gentle air blast.
The p~nels were then placed under black light (Fluorescent~ illumination and viewed. It was observed that the surfacq o~ all panels to which the above gel compositions I and II were applied, disclosed fluorescent indications from numerous readily defined microcracks therein, such fluorescent indicationQ being sharp and brilliant and revealing all de~
fectivQ conditions on the ~urface of the te~t panels.
The results of these tests showed the two gel pene-trant ~ormulations I and II each containing respectively ~ergitol nonionic 15-S-5 and Plura~ac A-24 nonionic sur~ac-20 tants, and the umed silica, to be highly heat resistant,non-migrating, non-lique~ying ~ormulations, and perorming effeatively under the drastic heated environment employed in the te~ts.
. : . ...:
~X~M LE 3 ~he grease-type d~e pene~rant composition of above Patent 3,465,l46 corresponding to composition I above, but contaLning ~-methyl-2-pyrrolidone as liquid vehicle for the - .
'' "
' ~Q~SSZ9~
dye instead of Tergitol 15-S-5, was tested by application to test panels of the type employed in Example 2 and heated under the same temperature conditions as :in Example 2.
After the period of heating, it was noted that the initially grease-like penetrant compositions applied to the surface of such panels had dried out and formed a powdery material.
Such powdery material was removed from the panel surfaces, a developer applied as in Example 2, and following removal of such developer the panels were viewed under fluor-escent light. It was found that unsatisfactory results were obtained, which did not provide the sensitivity, concentration and brilliance of the fluorescent indications which were observed on the test panels according to the procedure of Example 2 employing the gel compositionsI and II above.
Test~ ~ere carried out ~ollowing the procedure of Exampla 2 above, but employing test compositionæcorrespond-ing to compositions I and II above, wherein the proportion of Cab-0-Sil M-5 varied from 1 to 4 parts, to 1 part of the re-spective dye penetrant liquids A and B. ~he formulations thus produced ranged from thin cream-like gels employing the smaller proportions of the silica, to heavy grease-type gels when employing the higher proportions of silica O the g~ls in each case being essentially clear and translucent.
As in the case of Example 2, the gelled pen~etrants remained on the surface of the variously positioned and heated panels without dripping, runoff or pud~ling.
~!LV45S~9 Following removal of the excess dye p~netrant from the surface of the test panels, the remaining liquid dye :~
penetrants thus removed were biodegradableO :
In all cases the dye penetrant compo~ition performed :
excellently with bright fluorescent indications of the micro-crack~ obtained.
. .,: . .
The dye penetrant gel compositions of the invention are particularly applicable for use in detecting cracks, defects and metallurgical conditions in assemblies and parts which have been heat txeated and are still hot, recently welded assemblies and parts, aircraft stationed in hot cli- :
mates, rocket engines which are ~till hot, atomlc reactors : ~:
which require penetrant inspection while in ex~emely heated condition, and geothermal pre~sure ve3sels and piping.
From the foregoing, it i~ seen that the invantion provides a highly effective substantially biodegradable water washable dye penetrant composition in the form of a gel, which is heat resistant, nonflammable, and non~toxic, and which can be applied effectively to heated surfaces of parts positioned at various angle~, without runvE~ or dripping, and which can be readily removed rom a part surface by conventional wash ing. The dye penetrant gels of the invention contain as essential components a single carrier for the dye, which i~
preferably fluorescent, in the form of certain biodegradable oxyalkylated alcohols, and 8 substantial or major proportion of a ilica9 preerably fumed silica. Followîng removal o~
exce~s gel penetrant ~rom the surface of ~he parts and fur-ther processing of the part surfaces in the conventional ~ '"
' :''' ' ' .. . . . . . . . ~:
~5529 manner for viewing under ~uitable, e.g. fluorescent, light-ing conditions, fluorescent indicatio~ of high brilliance, definition and resolution of the dye traces from cracks and flaws in the part surfaces are obtainable, equivalent in this respect to the results obtained employing the same dye penetrant but in the absence of the silica.
Since various changes and modifications of the invention will occur to and can be made readily by those skilled in the art without departing from the invention con- -:
cept, the invention is not to be taken as limited except by the scope of the appended claims.
Claims (33)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A heat resistant biodegradable dye penetrant composition for use in non-destructive testing for detecting cracks and flaws and metallurgical conditions in the surface of an object, which comprises (1) a biodegradable nonionic surfactant which consists essentially of alkoxylates of essentially linear primary or secondary aliphatic alcohols, the linear aliphatic portion of said alcohols being alkyl chains containing in the range of from 8 to 20 carbon atoms, and containing an average of from 3 to 12 moles of an alkylene oxide of from 2 to 4 carbon atoms or mixture thereof, (2) a small amount of a dye soluble in said surfactant and (3) a substantial amount of silica sufficient to convert said dye penetrant composition into a gel.
2. A dye penetrant composition as defined in claim 1 wherein said surfactant is selected from the group consisting of (a) straight chain, primary, aliphatic oxyalkylated alcohols, wherein said alcohols can contain from 8 to 20 carbon atoms and the oxyalkyl groups are a mixture of ethylene oxide and propylene oxide groups, and (b) ethoxylates of linear secondary aliphatic alcohols, with the hydroxyl groups randomly distributed, the linear aliphatic portion of said alcohols being a mixture of alkyl chains containing in the range from 10 to 17 carbon atoms, and containing an average of from 3 to 12 moles of ethylene oxide.
3. A dye penetrant composition as defined in claim 2, said silica being present in an amount ranging from about 1 to about 8 parts, to 1 part by volume of the sum of said surfactant and said dye.
4. A dye penetrant composition as defined in claim 2, said dye being present in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight of said surfactant, and said silica being powdered silica present in an amount ranging from about 1 to about 6 parts, to 1 part by volume of the sum of said surfactant and said dye.
5. A dye penetrant composition as defined in claim 4, wherein said silica is fumed silica.
6. A dye penetrant composition as defined in claim 4, wherein said dye is a fluorescent dye.
7. A dye penetrant composition as defined in claim 2, wherein said surfactant is the sole liquid carrier for said dye.
8. A dye penetrant composition as defined in claim 2, wherein said surfactant (a) is a mixture of compounds having the formula:
R - O(A)H
wherein R is an essentially linear alkyl group having from 10 to 18 carbon atoms, at least 70 weight per cent of said compounds in said mixture having an R of from 12 to 16 carbon atoms, and A
is a mixture of oxypropylene and oxyethylene groups, said oxypropylene and oxyethylene groups being from 55 to 80% of the total weight of said compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1, and wherein said surfactant (b) is ethoxylates of a mixture of alcohols having the formula:
where n is in the range from 9 to 13 and m is an average of 3 to 12; and said dye is present in said composition in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight, of said surfactant, said composition being substantially non-flammable.
R - O(A)H
wherein R is an essentially linear alkyl group having from 10 to 18 carbon atoms, at least 70 weight per cent of said compounds in said mixture having an R of from 12 to 16 carbon atoms, and A
is a mixture of oxypropylene and oxyethylene groups, said oxypropylene and oxyethylene groups being from 55 to 80% of the total weight of said compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1, and wherein said surfactant (b) is ethoxylates of a mixture of alcohols having the formula:
where n is in the range from 9 to 13 and m is an average of 3 to 12; and said dye is present in said composition in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight, of said surfactant, said composition being substantially non-flammable.
9. A dye penetrant composition as defined in claim 8, wherein R in said surfactant (a) can have from 12 to 18 carbon atoms, and the total number of A groups can range from about 4 to about 14; and wherein in surfactant (b) the linear alkyl hydrophobic portion of said surfactant is a mixture of C11 to C15 linear chains, and the hydrophilic portion of said surfactant is a polyoxyethylene chain randomly attached to the linear alkyl hydrophobic chains through the ether linkage, and wherein said surfactant (b) is selected from the group consisting of said ethoxylates of said mixture of alcohols, wherein n ranges from 9 to 13, and m is an average of 3, 5, 7, 9 or 12.
10. A dye penetrant composition as defined in claim 9, said silica being present in an amount ranging from about 1 to about 8 parts, to 1 part by volume of the sum of said surfactant and said dye.
11. A dye penetrant composition as defined in claim 9, said dye being present in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight of said surfactant, and said silica being powdered silica present in an amount ranging from about 1 to about 6 parts, to 1 part by volume of the sum of said surfactant and said dye.
12. A dye penetrant composition as defined in claim 11, wherein said dye is a fluorescent dye, and said silica is fumed silica, said dye penetrant composition ranging from a thin cream-like gel to a heavy grease-type gel, said dye penetrant composition being non-dripping.
13. A dye penetrant composition as defined in claim 9, wherein said surfactant is said surfactant (b).
14. A dye penetrant composition as defined in claim 13, wherein said dye is a fluorescent dye, said silica is fumed silica, and said silica is present in an amount ranging from about 1 to about 6 parts, to 1 part by volume of the sum of said surfactant and said dye.
15. A dye penetrant composition as defined in claim 14, wherein said silica is present in an amount ranging from about 3 to about 6 parts, to 1 part by volume of the sum of said surfactant and said dye.
16. A dye penetrant composition as defined in claim 14, employing a combination of said biodegradable nonionic surfactants.
17. A dye penetrant composition as defined in claim 14, employing a combination of said biodegradable nonionic surfactants wherein m in one of said surfactants is an average of 5 and m in another of said surfactants is an average of 9.
18. A method for detecting cracks and flaws in the surface of an object, which comprises applying to said surface a water washable biodegradable heat resistant dye penetrant composition which comprises (1) a biodegradable nonionic surfactant which consists essentially of alkoxylates of essentially linear primary or secondary aliphatic alcohols, the linear aliphatic portion of said alcohols being alkyl chains containing in the range of from 8 to 20 carbon atoms, and containing an average of from 3 to 12 moles of an alkylene oxide of from 2 to 4 carbon atoms or mixture thereof, (2) a small amount of a dye soluble in said surfactant and (3) a substantial amount of silica sufficient to convert said dye penetrant composition into a gel, removing said dye penetrant composition from said surface without removing liquid dye penetrant from said cracks and flaws in said surface, and viewing the surface of said object under lighting conditions to obtain colored fraces from the said cracks and flaws.
19. A method as defined in claim 18 wherein said surfactant is selected from the group consisting of (a) straight chain, primary, aliphatic oxyalkylated alcohols, wherein said alcohols can contain from 8 to 20 carbon atoms and the oxyalkyl groups are a mixture of ethylene oxide and propylene oxide groups, and (b) ethoxylates of linear secondary aliphatic alcohols, with the hydroxyl groups randomly distributed, the linear aliphatic portion of said alcohols being a mixture of alkyl chains contain-ing in the range from 10 to 17 carbon atoms, and containing an average of from 3 to 12 moles of ethylene oxide.
20. A method as defined in claim 19, wherein said surface is a surface heated to elevated temperature and said silica is present in amount sufficient to prevent runoff when said surface is a slanted or vertical surface.
21. A method as defined in claim 20, said surface being heated to a temperature ranging from 100°F to about 300°F.
22. A method as defined in claim 20, said silica being present in an amount ranging from about 1 to about 8 parts, to 1 part by volume of the sum of said surfactant and said dye.
23. A method as defined in claim 20, said dye being present in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight of said surfactant, and said silica being powdered silica present in an amount ranging from about 1 to about 6 parts, to 1 part by volume of the sum of said surfactant and said dye.
24. A method as defined in claim 23, wherein said dye is a fluorescent dye, said silica is fumed silica, and said surface of said object is viewed under fluorescigenous light to obtain colored fluorescent traces from the dye in said cracks and flaws.
25. A method as defined in claim 19, wherein said surfactant (a) is a mixture of compounds having the formula:
R - O(A)H
wherein R is an essentially linear alkyl group having from 10 to 18 carbon atoms, at least 70 weight per cent of said compounds in said mixture having an R of from 12 to 16 carbon atoms, and A is a mixture of oxypropylene and oxyethylene groups, said oxypropylene and oxyethylene groups being from 55 to 80% of the total weight of said compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1; and wherein said surfactant (b) is ethoxylates of a mixture of alcohols having the formula:
where n is in the range from 9 to 13 and m is an average of 3 to 12; and said dye is present in said composition in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight, of said surfactant.
R - O(A)H
wherein R is an essentially linear alkyl group having from 10 to 18 carbon atoms, at least 70 weight per cent of said compounds in said mixture having an R of from 12 to 16 carbon atoms, and A is a mixture of oxypropylene and oxyethylene groups, said oxypropylene and oxyethylene groups being from 55 to 80% of the total weight of said compounds, the oxypropylene to oxyethylene ratio of said total weight being from 0.85:1 to 2.75:1; and wherein said surfactant (b) is ethoxylates of a mixture of alcohols having the formula:
where n is in the range from 9 to 13 and m is an average of 3 to 12; and said dye is present in said composition in an amount ranging from about 0.1 to 15 parts, per 100 parts, by weight, of said surfactant.
26. A method as defined in claim 25, wherein R in said surfactant (a) can have from 12 to 18 carbon atoms, and the total number of A groups can range from about 4 to about 14;
and wherein in surfactant (b) the linear alkyl hydrophobic portion of said surfactant is a mixture of C11 to C15 linear chains, and the hydrophilic portion of said surfactant is a polyoxyethylene chain randomly attached to the linear alkyl hydrophobic chains through the ether linkage, and wherein said surfactant (b) is selected from the group consisting of said ethoxylates of said mixture of alcohols, wherein n ranges from 9 to 13, and m is an average of 3, 5, 7, 9 or 12.
and wherein in surfactant (b) the linear alkyl hydrophobic portion of said surfactant is a mixture of C11 to C15 linear chains, and the hydrophilic portion of said surfactant is a polyoxyethylene chain randomly attached to the linear alkyl hydrophobic chains through the ether linkage, and wherein said surfactant (b) is selected from the group consisting of said ethoxylates of said mixture of alcohols, wherein n ranges from 9 to 13, and m is an average of 3, 5, 7, 9 or 12.
27. A method as defined in claim 26, wherein said surface is heated to elevated temperature, said silica being present in an amount ranging from about 1 to about 8 parts, to 1 part by volume of the sum of said surfactant and said dye.
28. A method as defined in claim 27, wherein said dye is a fluorescent dye, and said silica is fumed silica, employed in an amount ranging from about 1 to about 6 parts, to 1 part of the sum of said surfactant and said dye, said dye penetrant com-position ranging from a thin cream-like gel to a heavy grease-type gel, and being non-dripping, and said surface of said object is viewed under fluorescigenous light to obtain colored fluorescent traces from the dye in said cracks and flaws.
29. A method as defined in claim 28, wherein said surfactant is said surfactant (b).
30. A method as defined in claim 28, said removing said dye penetrant composition from said surface being carried out by a water wash.
31. A method as defined in claim 29, employing a combination of said surfactants wherein m in one of said surfactants is an average of 5 and m in another of said surfactants is an average of 9.
32. A method as defined in claim 31, wherein said removing said dye penetrant composition from said surface is carried out by a water wash.
33. A method as defined in claim 32, said surface being heated to a temperature ranging from 100°F to about 300°F.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/580,442 US4049568A (en) | 1974-02-21 | 1975-05-23 | Non-dripping heat resistant dye penetrant |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1045529A true CA1045529A (en) | 1979-01-02 |
Family
ID=24321121
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA252,416A Expired CA1045529A (en) | 1975-05-23 | 1976-05-13 | Non-dripping heat resistant dye penetrant and method of dye penetrant inspection |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1045529A (en) |
| DE (1) | DE2622997A1 (en) |
| FR (1) | FR2311835A1 (en) |
| GB (1) | GB1554185A (en) |
-
1976
- 1976-05-13 CA CA252,416A patent/CA1045529A/en not_active Expired
- 1976-05-17 GB GB2030376A patent/GB1554185A/en not_active Expired
- 1976-05-21 FR FR7615551A patent/FR2311835A1/en active Granted
- 1976-05-22 DE DE19762622997 patent/DE2622997A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE2622997A1 (en) | 1976-12-09 |
| FR2311835A1 (en) | 1976-12-17 |
| GB1554185A (en) | 1979-10-17 |
| FR2311835B3 (en) | 1979-02-16 |
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