CA2212554A1 - Non-cfcs solder flux composition - Google Patents
Non-cfcs solder flux compositionInfo
- Publication number
- CA2212554A1 CA2212554A1 CA 2212554 CA2212554A CA2212554A1 CA 2212554 A1 CA2212554 A1 CA 2212554A1 CA 2212554 CA2212554 CA 2212554 CA 2212554 A CA2212554 A CA 2212554A CA 2212554 A1 CA2212554 A1 CA 2212554A1
- Authority
- CA
- Canada
- Prior art keywords
- acid
- organic solvent
- hydrofluoric acid
- evaporative
- evaporative organic
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/3612—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with organic compounds as principal constituents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/3612—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with organic compounds as principal constituents
- B23K35/3618—Carboxylic acids or salts
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
A blend mixture of non-toxic, non-corrosive liquid soldering flux consists essentially of a solution of hydrofluoric acid, formic acid, benzyl alcohols, 1-naphthylacetic acid in iso-propanol. Neither precleaning nor postcleaning of the pieces being joined is necessary. The flux evaporates completely upon heating, leaving no corrosive residue or other product on the surface of the piece. The composition comprises about, a) 60-95% by weight iso-propanol, b) 1-10% by weight formic acid, c) 0.5-8% by hydrofluoric acid, d) 0-5% by weight benzyl alcohol, and e) 0-10% by weight 1-naphthylacetic acid.
Description
CA 02212554 1997-09-i2 "Non-Cl;Cs Solder Flll~ Composition"
nackground otthe Invention 1. I~ield of the lnvention The present invention relates gencrally to environmentally safe flux removing compositions specifically rormulated for clcaning electronic circuit assemblies, such as printcd circuit boards, during the fabrication thereof. Aryl alcohol (benzyl alcohol), hydtofluoric acid, rormic acid, and l-naphthylacetic acid in a solvent, such as isopropanol, are used to remove soldcr nux, oils, waxes and greasy substances, as well as adllesive and other residues from various n substrates.
nackground otthe Invention 1. I~ield of the lnvention The present invention relates gencrally to environmentally safe flux removing compositions specifically rormulated for clcaning electronic circuit assemblies, such as printcd circuit boards, during the fabrication thereof. Aryl alcohol (benzyl alcohol), hydtofluoric acid, rormic acid, and l-naphthylacetic acid in a solvent, such as isopropanol, are used to remove soldcr nux, oils, waxes and greasy substances, as well as adllesive and other residues from various n substrates.
2. Description of the Prior t~rt Soldering with a soft solder, such as tin-lcad based alloy melting at between 200"C to 260~C, is widely employed in the electrical and electronics industnes. In order to produce a satisfactory soldered joint, it is nccessary to use a flux with the so~ solder in order to remove any residual surface oxide films and hence providc a clean sulface and in order to reduce the surface tension of the molten solder and hence promote good wetting of the surface by the solder. It is important that the mol~en solder fiully wct thc surfaces to be Joined during the tinning step, as unwet portions result in voids at tlle surfaces aner soldering is complete, and the voids can cause 2() later failure of the bond.
Therefore, the surface to be fluxed must be cleaned of a portion of the oxide and colllaminalll coating prior to fluxing. Equally important, the soldered array must be carefully cleaned after soldering is complete, in a postclcaning process, to remove any unreacted ~lux and reaction products of the flux treatment. ~ny remaining flux or reaction products can continue reacting with the bonded pieces and corrode them during service. Such corrosion causcd by nuxes is a major concern for many types of soldcr bonding, as the bonded pieces are sometimes s uscd in environments having conditions such as higll humidity and high temperature that accelerate corrosion re~ctions that might otherwise procced slowly. Tiny amounts of unreacted llux or rcaction products that remain on the surface fiollowing soldering and postcleaning can thcrefore have disastrous conscquenccs. Bccause of the consequences of solder faiiures and the significance of solder joints, thc soldering process has been studied extensively.
1() Fluxes now in use include mixtures of inorganic acids in inorganic vehicles or solvents such as water, inorganic acids in petrolatum pas~es, salls in water, petrolatum paste or organic solvcnt, organic acids in watcr, organic halogcns in water, amines and amides in water, and natural or modified rosins. All of ~hcse nu~cs rcqllire postcleaning of the soldeted joint. ~luxing can also be carried out in a reducing environmcnt, as by accomplishing the soldering ptocess in a IS hydrogen gas atmosphere Postcleaning is not required, but m~inten~tlce and use of a pure hydrogcn atmosphere in large scale produc~ion opcrations is difficult, and can lead to related hydrogen embrit~lement. In sum, thcre is known no effcctive, generally applicable apptoach to fluxing which avoids the need for postcleanin~ of the soldcred parts.
There exists a nced for an improved appro~ch to soldering, and patticularly to the fluxing operation, which incrcascs the reliability of Ihc jOining process by promoting effèctive wetting of the solder to the picce during the tinning stcp, and also rcduces the incidence of post-soldering railures due to corrosion or rcla~ed causcs. Work continues in an effort to develop suitable fluxes that permit making a solder joint faster and bettcr, in a manner that is both environmentally acceptable and also does not require special prccautions to protect the health and productivity of production line workers.
Summary Or the ~nvention The present invention provides a soldcr tlux, and relatcd method for fluxing a surface and for joining two pieces together using the flux. T lle nux promotes even, smooth, regular wetting of the surface of the piece by solder, with a virtual absence of unwetted portions. Use of the flux does not require cleaning of the surface prior to {luxing or postcleaning of the bonded portions of the pieces after soldering is complete. The flux evaporates entirely during the fluxing process, leaving no residue or reaction products to interfere with the use of the bonded components, or cause corrosion or other harmful post-bonding efFects. At ambient ten~e.al~lte, the flux is a liquid having a viscosity comparable with that of waler, and can be readily provided in open containers at the point of use. The vapors from many embodiments of the flux are not odorous 1 s and of~ensive to persons who use the flux, and contact of the flux to the body does not cause injury. The flux can therefore bc used in asscmbly operations involving hand labor without special precautions such as required wi~h somc otl1er nuxcs.
In the past, strong inorganic acids sucll as hydrocllloric and hydrobromic acids have been incorporated into certain synthctic organic acids, which arc then processed into esters for use in 2() nuxes ~Jowever, hydrofluoric acid has been generally considered too strong an acid for widespread use in fluxes, becausc tiny amoun~s of residues could cause serious colTosion damage, and because the hydrofluoric acid attacks glass and ccramics used in many electronic components.
llydrofluoric acid has occasionally been used in water and petrolatum mixtures, but such use has been restricted due to the activity of tlle acid. It has now been found that hydrofluorie acid effects the fluxing operation when mixed with an evaporative organie solvent. The flux of the invention is applied to the surface to be nuxed by brielly immersing the surfaee into the flux, spraying the S tlux onto the surface, or by other convenient means. The surface is then tinned by dipping the surface into liquid solder, brushing the liquid solder onto ~he surface, or other eonvenient means.
When the flux of the invention is uscd, the surface to be fluxed and bonded need not be specially cleaned prior to application of the llux. rhe ~urface should not ha~e grease, thick dirt, or other impenetrable barrier that preven~s contact of the licluid flux to the surface. In the other n aspect of the invention, an evaporative organic acid is mixed with an e~apolative organie solvent to form a fiux. The evaporative organic acid must be present in an effeetive amount, which is typically in the range of from about 1 part of acid to 50 parts of solvent. ~ull fluxing effeetiveness is normally reached with about I part of the acid ror 50 parts of the solvent. Howevet, the general level of effeetiveness reached using evaporative organie aeids is less than that reaehed 15 using hydrofluorie acid, and therefore the nux mixture of hydrofluorie aeid and evaporative organie solvent is preferred. Acceptable evaporative organic solvent would be isopropallol and benzyl alcohol. Acceptable evaporative organic acids are those that evaporate fully at the fluxing temperature when mixed with the solvent. I-Naphthylacetie acid and forrnie acid are espeeially preferred in this embodiment. Inorganic acids ~llch as hydrofluorie aeid, hydrochlorie aeid, 2t) hydrobromic aeid and hydroiodie acid can be added, either singly or in eolnbination.
A wide variety of types of pieces can be fiuxed and joined by the proeesses of the invention. Conventional electronic components such as resistors, diodes, eapacitors, transistors, integrated circuits, and the like are included. Subassemblies can be fo~med or joined. Wires, connectors, printed wiring boards, and the like can be joined together or with active components.
The processes are also operable in conjunction with non-electronie soldenng operations, such as general metal joining, fabrica~ion, and the like. There are no known limitations on such uses of s the llux.
It will be apprecia~ed that ~he present invetltion presents an ill~pOI lant advanee in the art of soldering and fluxes. The flux of the invention is highly effective in prol-lolillg wetting of the portions of components to be joined by solder, produeing an evenly tinned surface. The flux and its reaetion products evaporate completely by the conclusion of the fluxing operation, so that 1() postcleaning is not required even though the flux contains a strong acid. The flux is easy to use in nuxing the surfaees and in bonding components. lt is not dangerous to eontact to the skin, and does not have an objec~ionable odor, so that the n.,~ can be used in mas~ production soldering operations.
Further, the purpose of the foregoing Abstract is to enable the Can~ n Intellectual 5 Property Office (CIPO) and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terrns of phraseology, to determine quickly from a c~lrsory inspection the nature and essence of the technical disclosure of the application Aceordingly, the Abstract is nei~her in~ended to define the invention ot the application, whieh only is measured by the claims, nor is it intended to be limiting as to the scope 2() of the invention in any way.
It is therefore an object Or the present invention to provide a new and improved composition for cleaning the surface of various soldered articles and which has all of the advantages of the prior art and none of the disadvantages.
It is another object of the present invention to provide a new and improved composition for cleaning the surface of various soldercd articles which may be efficiently manufactured and marketed.
An even further object Or the prescnt invention is to provide a new and improved composition for cleaning the surracc of various soldered articles which is susceptible of a low cost ormanufacture with regard to both materials and labor, and whi~h accordingly is then susceptible n of low prices of sale to the consuming public, thereby making such composition available to the buying public.
Still yet a filrther object of the present invention is to provide a new and improved composition for cleaning the surface of various ~oldered articles and which is adapted to be topically applied to such articles in a colourless thin liquid, easily sprayable form.
1~ These together with still other objects of the invention, along with the various features of novelty which charactcrize the invention, are pointcd out with particularity in the claims forming a part of this disclosure. l~or a better underst~rld;llg of the invcntion, its operating advantages and the specific objects attained by its uscs, rcrercllce should be made to the following detailed description of the prcferrcd embodimcnts or tl~c illVCIlliOn.
2n c, iplion Or the prererred Embodiment ~he present invention is embodied in a flux used in conjunction with soldering. The flux preferably is a mixture of llydrofluoric acid, formic acid, I-naphtylacetic acid and the evaporative organic solvent~ including isopropanol and benzyl alcollol, with the ratio of acid and solvent being .~ from about 1 to about 10 parts of hydrofluoric acid for each 46 parts of evaporative organic solvent. While greater propor~ions of acid are opcrable, completely effective results are obtained with les~ than about 10 parts of acid, and ~here is less danger from acid burns. Preferably, the solvent is isopropanol. Both the hydrolluoric ~cid and isopropanol should be without impurities that would not evaporate during nuxing.
n A nux having reagent grade hydrofluoric acid provided as an aqueous solution of 49 percent hydrogen fluoride, and reagent grade formic acid provided as an aqueous solution of 85 percent formic acid, and reagent 8rade isopropanol, mixed in the ratio of 2 parts by volume of hydrofluoric acid to 46 parts by volumc of isopropanol, is the presently most preferred cmbodiment of the invention. This flux mixture is prcparcd by adding the required volume of n~ hydrofluoric acid slowly to the isopropanol, taking care not to splatter the acid or overheat the solution. Concentrated hydrofluoric acid is polcnially dan~erous, as it is a very strong acid that rapidly attacks human tissue. Conscqucntly, thc preparation of the flux mixture should be accomplished by a person skillcd in making acid mixtures, using good ventilation and appropriate safety equipment including at Icast gogglcs, a nlbbcr apron, and rubber gloves.
2() Once, the flux mixture is pre~ared, thc conccntration of hydrofluoric acid i~ sufflciently low that there is a greatly reduccd risk of injury. Tlle tlux mixture can be contacted to the skin for brief pcriods without burns or injury, although i~ is rccommended that any nux touching the skin bc washed away as soon as possible. Neverthcless, the fiux mixture is much safer than many other commercial liquid tluxes, which quickly burn the skin. The dominant odor of the flux is that of the solvent, in the preferred case the isopropanol. While prolonged exposure to this odor is not recommended, exposure to a weak odor or for brief periods is not ;~llmediately harrnfill. Thus, ~he fiux is safe to handle in ordinary conditions of good ventilation and a reasonably safe working envilonll,ellt. It is seen that the llux and approacll of the present invention yield important advantages in soldering. Good tinning and soldcring are achieved, without the need for cleaning and postcleaning. The tlux is nontoxic, and can bc used in production operations where hand wiring is done.
While the present invention has been fully described above with particularity and detail in connection with what is presently deemed to be thc most practical and p.~fel.ed examples of the invcntion, it will be apparent to those of ordinary skill in the art that many modifications thereof may be made without departing from the principles and concepts set forth herein. Hence, the proper scope of the present invention should be determined only by the broadest interpretation of 1~ the appended claims so as to encompass all sucl1 modifications.
2()
Therefore, the surface to be fluxed must be cleaned of a portion of the oxide and colllaminalll coating prior to fluxing. Equally important, the soldered array must be carefully cleaned after soldering is complete, in a postclcaning process, to remove any unreacted ~lux and reaction products of the flux treatment. ~ny remaining flux or reaction products can continue reacting with the bonded pieces and corrode them during service. Such corrosion causcd by nuxes is a major concern for many types of soldcr bonding, as the bonded pieces are sometimes s uscd in environments having conditions such as higll humidity and high temperature that accelerate corrosion re~ctions that might otherwise procced slowly. Tiny amounts of unreacted llux or rcaction products that remain on the surface fiollowing soldering and postcleaning can thcrefore have disastrous conscquenccs. Bccause of the consequences of solder faiiures and the significance of solder joints, thc soldering process has been studied extensively.
1() Fluxes now in use include mixtures of inorganic acids in inorganic vehicles or solvents such as water, inorganic acids in petrolatum pas~es, salls in water, petrolatum paste or organic solvcnt, organic acids in watcr, organic halogcns in water, amines and amides in water, and natural or modified rosins. All of ~hcse nu~cs rcqllire postcleaning of the soldeted joint. ~luxing can also be carried out in a reducing environmcnt, as by accomplishing the soldering ptocess in a IS hydrogen gas atmosphere Postcleaning is not required, but m~inten~tlce and use of a pure hydrogcn atmosphere in large scale produc~ion opcrations is difficult, and can lead to related hydrogen embrit~lement. In sum, thcre is known no effcctive, generally applicable apptoach to fluxing which avoids the need for postcleanin~ of the soldcred parts.
There exists a nced for an improved appro~ch to soldering, and patticularly to the fluxing operation, which incrcascs the reliability of Ihc jOining process by promoting effèctive wetting of the solder to the picce during the tinning stcp, and also rcduces the incidence of post-soldering railures due to corrosion or rcla~ed causcs. Work continues in an effort to develop suitable fluxes that permit making a solder joint faster and bettcr, in a manner that is both environmentally acceptable and also does not require special prccautions to protect the health and productivity of production line workers.
Summary Or the ~nvention The present invention provides a soldcr tlux, and relatcd method for fluxing a surface and for joining two pieces together using the flux. T lle nux promotes even, smooth, regular wetting of the surface of the piece by solder, with a virtual absence of unwetted portions. Use of the flux does not require cleaning of the surface prior to {luxing or postcleaning of the bonded portions of the pieces after soldering is complete. The flux evaporates entirely during the fluxing process, leaving no residue or reaction products to interfere with the use of the bonded components, or cause corrosion or other harmful post-bonding efFects. At ambient ten~e.al~lte, the flux is a liquid having a viscosity comparable with that of waler, and can be readily provided in open containers at the point of use. The vapors from many embodiments of the flux are not odorous 1 s and of~ensive to persons who use the flux, and contact of the flux to the body does not cause injury. The flux can therefore bc used in asscmbly operations involving hand labor without special precautions such as required wi~h somc otl1er nuxcs.
In the past, strong inorganic acids sucll as hydrocllloric and hydrobromic acids have been incorporated into certain synthctic organic acids, which arc then processed into esters for use in 2() nuxes ~Jowever, hydrofluoric acid has been generally considered too strong an acid for widespread use in fluxes, becausc tiny amoun~s of residues could cause serious colTosion damage, and because the hydrofluoric acid attacks glass and ccramics used in many electronic components.
llydrofluoric acid has occasionally been used in water and petrolatum mixtures, but such use has been restricted due to the activity of tlle acid. It has now been found that hydrofluorie acid effects the fluxing operation when mixed with an evaporative organie solvent. The flux of the invention is applied to the surface to be nuxed by brielly immersing the surfaee into the flux, spraying the S tlux onto the surface, or by other convenient means. The surface is then tinned by dipping the surface into liquid solder, brushing the liquid solder onto ~he surface, or other eonvenient means.
When the flux of the invention is uscd, the surface to be fluxed and bonded need not be specially cleaned prior to application of the llux. rhe ~urface should not ha~e grease, thick dirt, or other impenetrable barrier that preven~s contact of the licluid flux to the surface. In the other n aspect of the invention, an evaporative organic acid is mixed with an e~apolative organie solvent to form a fiux. The evaporative organic acid must be present in an effeetive amount, which is typically in the range of from about 1 part of acid to 50 parts of solvent. ~ull fluxing effeetiveness is normally reached with about I part of the acid ror 50 parts of the solvent. Howevet, the general level of effeetiveness reached using evaporative organie aeids is less than that reaehed 15 using hydrofluorie acid, and therefore the nux mixture of hydrofluorie aeid and evaporative organie solvent is preferred. Acceptable evaporative organic solvent would be isopropallol and benzyl alcohol. Acceptable evaporative organic acids are those that evaporate fully at the fluxing temperature when mixed with the solvent. I-Naphthylacetie acid and forrnie acid are espeeially preferred in this embodiment. Inorganic acids ~llch as hydrofluorie aeid, hydrochlorie aeid, 2t) hydrobromic aeid and hydroiodie acid can be added, either singly or in eolnbination.
A wide variety of types of pieces can be fiuxed and joined by the proeesses of the invention. Conventional electronic components such as resistors, diodes, eapacitors, transistors, integrated circuits, and the like are included. Subassemblies can be fo~med or joined. Wires, connectors, printed wiring boards, and the like can be joined together or with active components.
The processes are also operable in conjunction with non-electronie soldenng operations, such as general metal joining, fabrica~ion, and the like. There are no known limitations on such uses of s the llux.
It will be apprecia~ed that ~he present invetltion presents an ill~pOI lant advanee in the art of soldering and fluxes. The flux of the invention is highly effective in prol-lolillg wetting of the portions of components to be joined by solder, produeing an evenly tinned surface. The flux and its reaetion products evaporate completely by the conclusion of the fluxing operation, so that 1() postcleaning is not required even though the flux contains a strong acid. The flux is easy to use in nuxing the surfaees and in bonding components. lt is not dangerous to eontact to the skin, and does not have an objec~ionable odor, so that the n.,~ can be used in mas~ production soldering operations.
Further, the purpose of the foregoing Abstract is to enable the Can~ n Intellectual 5 Property Office (CIPO) and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terrns of phraseology, to determine quickly from a c~lrsory inspection the nature and essence of the technical disclosure of the application Aceordingly, the Abstract is nei~her in~ended to define the invention ot the application, whieh only is measured by the claims, nor is it intended to be limiting as to the scope 2() of the invention in any way.
It is therefore an object Or the present invention to provide a new and improved composition for cleaning the surface of various soldered articles and which has all of the advantages of the prior art and none of the disadvantages.
It is another object of the present invention to provide a new and improved composition for cleaning the surface of various soldercd articles which may be efficiently manufactured and marketed.
An even further object Or the prescnt invention is to provide a new and improved composition for cleaning the surracc of various soldered articles which is susceptible of a low cost ormanufacture with regard to both materials and labor, and whi~h accordingly is then susceptible n of low prices of sale to the consuming public, thereby making such composition available to the buying public.
Still yet a filrther object of the present invention is to provide a new and improved composition for cleaning the surface of various ~oldered articles and which is adapted to be topically applied to such articles in a colourless thin liquid, easily sprayable form.
1~ These together with still other objects of the invention, along with the various features of novelty which charactcrize the invention, are pointcd out with particularity in the claims forming a part of this disclosure. l~or a better underst~rld;llg of the invcntion, its operating advantages and the specific objects attained by its uscs, rcrercllce should be made to the following detailed description of the prcferrcd embodimcnts or tl~c illVCIlliOn.
2n c, iplion Or the prererred Embodiment ~he present invention is embodied in a flux used in conjunction with soldering. The flux preferably is a mixture of llydrofluoric acid, formic acid, I-naphtylacetic acid and the evaporative organic solvent~ including isopropanol and benzyl alcollol, with the ratio of acid and solvent being .~ from about 1 to about 10 parts of hydrofluoric acid for each 46 parts of evaporative organic solvent. While greater propor~ions of acid are opcrable, completely effective results are obtained with les~ than about 10 parts of acid, and ~here is less danger from acid burns. Preferably, the solvent is isopropanol. Both the hydrolluoric ~cid and isopropanol should be without impurities that would not evaporate during nuxing.
n A nux having reagent grade hydrofluoric acid provided as an aqueous solution of 49 percent hydrogen fluoride, and reagent grade formic acid provided as an aqueous solution of 85 percent formic acid, and reagent 8rade isopropanol, mixed in the ratio of 2 parts by volume of hydrofluoric acid to 46 parts by volumc of isopropanol, is the presently most preferred cmbodiment of the invention. This flux mixture is prcparcd by adding the required volume of n~ hydrofluoric acid slowly to the isopropanol, taking care not to splatter the acid or overheat the solution. Concentrated hydrofluoric acid is polcnially dan~erous, as it is a very strong acid that rapidly attacks human tissue. Conscqucntly, thc preparation of the flux mixture should be accomplished by a person skillcd in making acid mixtures, using good ventilation and appropriate safety equipment including at Icast gogglcs, a nlbbcr apron, and rubber gloves.
2() Once, the flux mixture is pre~ared, thc conccntration of hydrofluoric acid i~ sufflciently low that there is a greatly reduccd risk of injury. Tlle tlux mixture can be contacted to the skin for brief pcriods without burns or injury, although i~ is rccommended that any nux touching the skin bc washed away as soon as possible. Neverthcless, the fiux mixture is much safer than many other commercial liquid tluxes, which quickly burn the skin. The dominant odor of the flux is that of the solvent, in the preferred case the isopropanol. While prolonged exposure to this odor is not recommended, exposure to a weak odor or for brief periods is not ;~llmediately harrnfill. Thus, ~he fiux is safe to handle in ordinary conditions of good ventilation and a reasonably safe working envilonll,ellt. It is seen that the llux and approacll of the present invention yield important advantages in soldering. Good tinning and soldcring are achieved, without the need for cleaning and postcleaning. The tlux is nontoxic, and can bc used in production operations where hand wiring is done.
While the present invention has been fully described above with particularity and detail in connection with what is presently deemed to be thc most practical and p.~fel.ed examples of the invcntion, it will be apparent to those of ordinary skill in the art that many modifications thereof may be made without departing from the principles and concepts set forth herein. Hence, the proper scope of the present invention should be determined only by the broadest interpretation of 1~ the appended claims so as to encompass all sucl1 modifications.
2()
Claims (16)
1. A soldering flux, consisting essentially of a mixture of an evaporative organic solvent and an acid selected from the group consisting of hydrofluoric acid and an evaporative organic acid, the acid being present in an effective amount less than the solubility limit in the evaporative organic solvent.
2. The composition of claim 1 comprising, by weight of the total composition of:
i). 60 to 95% of organic solvent selected from the class consisting short-chain alcohol, ii). 1 to 10% of evaporative organic acid consisting short-chain carboxylic acid, iii). 0.5 to 8% of inorganic acid containing hydrofluoric acid, iv). 0 to 5% of organic solvent selected from the class consisting aryl alcohol, v). 0 to 10% of evaporative organic acid consisting conjugated aromatic carboxylic acid.
i). 60 to 95% of organic solvent selected from the class consisting short-chain alcohol, ii). 1 to 10% of evaporative organic acid consisting short-chain carboxylic acid, iii). 0.5 to 8% of inorganic acid containing hydrofluoric acid, iv). 0 to 5% of organic solvent selected from the class consisting aryl alcohol, v). 0 to 10% of evaporative organic acid consisting conjugated aromatic carboxylic acid.
3. The flux of claim 1, wherein the acid is hydrofluoric acid, and the ratio of hydrofluoric acid to evaporative organic solvent is from about 1 to about 10 parts of hydrofluoric acid, to about 46 parts of evaporative organic solvent.
4. The flux of claim 1, wherein the acid is hydrofluoric acid, and the ratio of hydrofluoric acid to evaporative organic solvent is about 2 parts of hydrofluoric acid to about 46 parts of evaporative organic solvent.
5. The flux of claim 1, wherein the evaporative organic solvent is selected from the group consisting of isopropanol and benzyl alcohol.
6. The flux of claim 1, further including an organic acid.
7. The flux of claim 1, wherein the flux is a mixture of about 2 parts of hydrofluoric acid in about 46 parts of isopropanol.
8. A method for fluxing the surface of a portion on a piece, comprising the steps of:
i). Furnishing a piece to be fluxed;
ii). Contacting the portion to be fluxed to a solution consisting essentially of a mixture of an evaporative organic solvent and an acid selected from the group consisting of hydrofluoric acid and an evaporative organic acid, the acid being present in an effective amount less than the solubility limit in the evaporative organic solvent;
iii). Heating the contacted portion to a temperature at which the hydrofluoric acid reacts with the oxides on the surface, and the solution evaporates.
i). Furnishing a piece to be fluxed;
ii). Contacting the portion to be fluxed to a solution consisting essentially of a mixture of an evaporative organic solvent and an acid selected from the group consisting of hydrofluoric acid and an evaporative organic acid, the acid being present in an effective amount less than the solubility limit in the evaporative organic solvent;
iii). Heating the contacted portion to a temperature at which the hydrofluoric acid reacts with the oxides on the surface, and the solution evaporates.
9. In claim 7, wherein the acid is hydrofluoric acid, and the ratio of hydrofluoric acid to evaporative organic solvent is from about 1 to about 10 parts of hydrofluoric acid, to about 46 parts of evaporative organic solvent.
10. In claim 7, wherein the acid is hydrofluoric acid, and the ratio of hydrofluoric acid to evaporative organic solvent is about 2 parts of hydrofluoric acid, to about 46 parts of evaporative organic solvent.
11. The flux of claim 7, wherein the acid is the evaporative organic acid 1-naphtylacelic acid.
12. A method for joining portions or two pieces, comprising the steps of:
i). Furnishing the two pieces to be joined;
ii). Contacting the portions to be joined to a solution consisting essentially of a mixture of an evaporative organic solvent and an acid selected from the group consisting of hydrofluoric acid and an evaporative organic acid, the acid being present in an effective amount less than the solubility limit in the evaporative organic solvent;
iii). Applying a metallic solder to at least one of the portions to be joined to tin the portion at a temperature above the melting temperature of the solder;
iv). Contacting the two portions to h e joined at a temperature above the melting point of the metallic solder and then cooling the contacted portions to a temperature below the melting point of the metallic solder, thereby joining the contacted portions together, said method being accomplished without any postcleaning of the joined components.
i). Furnishing the two pieces to be joined;
ii). Contacting the portions to be joined to a solution consisting essentially of a mixture of an evaporative organic solvent and an acid selected from the group consisting of hydrofluoric acid and an evaporative organic acid, the acid being present in an effective amount less than the solubility limit in the evaporative organic solvent;
iii). Applying a metallic solder to at least one of the portions to be joined to tin the portion at a temperature above the melting temperature of the solder;
iv). Contacting the two portions to h e joined at a temperature above the melting point of the metallic solder and then cooling the contacted portions to a temperature below the melting point of the metallic solder, thereby joining the contacted portions together, said method being accomplished without any postcleaning of the joined components.
13. In claim 11, wherein at least one of the pieces is an electronic component.
14. In claim 11, wherein the acid is hydrofluoric acid, and the ratio of hydrofluoric acid to evaporative organic solvent is about 2 parts of hydrofluoric acid, to about 46 parts of evaporative organic solvent.
15. In claim 11, wherein the acid is hydrofluoric acid and the evaporative organic solvent is a mixture of isopropanol and benzyl alcohol.
16. In claim 11, wherein the acid is hydrofluoric acid, the evaporative organic solvent is a mixture of isopropanol and benzyl alcohol and the evaporative organic acid is 1-naphthylacetic acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2212554 CA2212554A1 (en) | 1997-09-22 | 1997-09-22 | Non-cfcs solder flux composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2212554 CA2212554A1 (en) | 1997-09-22 | 1997-09-22 | Non-cfcs solder flux composition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2212554A1 true CA2212554A1 (en) | 1999-03-22 |
Family
ID=4161226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2212554 Abandoned CA2212554A1 (en) | 1997-09-22 | 1997-09-22 | Non-cfcs solder flux composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2212554A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111836695A (en) * | 2018-03-09 | 2020-10-27 | 株式会社欧利生 | Flux, solder paste, soldering process, method for manufacturing soldered product, and method for manufacturing BGA package |
| CN112247400A (en) * | 2020-10-13 | 2021-01-22 | 浙江新锐焊接科技股份有限公司 | Inorganic bonding system for water-based environment-friendly brazing flux and application thereof |
-
1997
- 1997-09-22 CA CA 2212554 patent/CA2212554A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111836695A (en) * | 2018-03-09 | 2020-10-27 | 株式会社欧利生 | Flux, solder paste, soldering process, method for manufacturing soldered product, and method for manufacturing BGA package |
| CN112247400A (en) * | 2020-10-13 | 2021-01-22 | 浙江新锐焊接科技股份有限公司 | Inorganic bonding system for water-based environment-friendly brazing flux and application thereof |
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