EP0015336A1 - Method of cleaning metals - Google Patents

Method of cleaning metals Download PDF

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Publication number
EP0015336A1
EP0015336A1 EP79300966A EP79300966A EP0015336A1 EP 0015336 A1 EP0015336 A1 EP 0015336A1 EP 79300966 A EP79300966 A EP 79300966A EP 79300966 A EP79300966 A EP 79300966A EP 0015336 A1 EP0015336 A1 EP 0015336A1
Authority
EP
European Patent Office
Prior art keywords
emulsifier
solvent
cleaning
cleaner
concentration
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.)
Withdrawn
Application number
EP79300966A
Other languages
German (de)
French (fr)
Inventor
Luigi Dare
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
REEF CHEMICAL Corp (PROPRIETARY)LIMITED
Original Assignee
REEF CHEMICAL Corp (PROPRIETARY)LIMITED
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by REEF CHEMICAL Corp (PROPRIETARY)LIMITED filed Critical REEF CHEMICAL Corp (PROPRIETARY)LIMITED
Publication of EP0015336A1 publication Critical patent/EP0015336A1/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/78—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
    • C23G5/06—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents using emulsions

Definitions

  • This invention relates to the cleaning of metals and more particularly ferrous metals prior to the application of paint.
  • the cleaning is usually effected by sprays of a dilute alkaline metal cleaner used at ambient temperatures or above. There are usually two spray cleaning steps with the first step using a higher strength than the second. These are followed by spray rinsing to remove the residues of the cleaning solutions prior to phosphating.
  • the latter process is very sensitive to alkali contamination, to any carry-over of solvents and to soil contamination.
  • prewipe solvent-emulsifier are added into the first cleaning solution to assist cleaning, but always at a low level equal or less than the concentration of the alkali metal cleaner used. It has always been feared that such additives could carry over to contaminate the second cleaner system and not be removed to an adequate extent prior to phosphating.
  • the present invention is based on the surprising and unexpected discovery that high level additions of solvent-emulsifier to the first or only cleaning stage, and minor additions to the second cleaning stage, if present, can be used with success and can replace prewiping entirely.
  • the present invention provides a method in which metal articles are sprayed in at least one cleaning stage by means of an aqueous cleaning liquid containing an alkali metal cleaner and the articles are spray rinsed prior to phosphating, wherein a solvent-emulsifier is added to the cleaning liquid in the first cleaning stage at a concentration which is at least twice as high as the concentration of the alkali metal cleaner, which is present at a concentration of 1.0% or less.
  • the emulsifier of the solvent-emulsifier may be non-ionic, anionic or mixtures thereof.
  • the solvent-emulsifier may be present in a concentration which is up to 30 times as high as the concentration of the alkali metal cleaner, without any adverse effects on the subsequent phosphating step.
  • concentration of the solvent-emulsifier the better are the economics. It is therefore preferred to operate using a concentration of the solvent-emulsifier which is about 2 to 3 times the concentration of the alkali metal cleaner.
  • the practice was to use 5000tof solvent-emulsifier each month and it was applied manually in a prewipe operation.
  • the first cleaner was operated at a percentage of 0.5% of cleaner at 50°C and a spray pressure of 2 Bar.
  • the strength of the second cleaner solution was 0.3% at 55°C at a spray pressure of 2 Bar.
  • the present invention was applied to the same plant with no adverse effects on the phosphating over a period of 8 weeks. No prewipe was applied.
  • the first cleaner operated with the same alkali cleaner consisting of 0.5% by mass of a solution in water as set out below. To this was added 3.0% by mass of a solvent-emulsifier as set out below.
  • the spray pressure was 3 Bar and the temperature was kept at ambient.
  • the second cleaner operated with the same alkali cleaner at 0.3% by mass plus the same solvent-emulsifier at 0.05% by mass.
  • the spray pressure was 2 Bar and the temperature 55°C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Detergent Compositions (AREA)

Abstract

Ferrous metal parts are prepared for painting without a prewipe, but passed through two cleaning stages prior to phosphating. The parts are spray cleaned in the first stage by means of an aqueous liquid containing an alkali metal cleaner and a solvent-emulsifier, the concentration of the latter being several times that of the cleaner. In the second stage the parts are spray rinsed with a solution also containing an alkali cleaner and a lesser amount of a solvent-emulsifier.

Description

  • This invention relates to the cleaning of metals and more particularly ferrous metals prior to the application of paint.
  • In the automotive and appliance industries it is common practice to use a spray cleaning process to remove oil, grease and protective oils, hereinafter collectively called "soil", from the metal surface prior to phosphating and painting. To facilitate cleaning it is common practice to prewipe the metal with a solvent-emulsifier combination to loosen and soften the soil.
  • The cleaning is usually effected by sprays of a dilute alkaline metal cleaner used at ambient temperatures or above. There are usually two spray cleaning steps with the first step using a higher strength than the second. These are followed by spray rinsing to remove the residues of the cleaning solutions prior to phosphating. The latter process is very sensitive to alkali contamination, to any carry-over of solvents and to soil contamination.
  • Not all plants use a prewipe system. In some cases relatively small amounts of the prewipe solvent-emulsifier are added into the first cleaning solution to assist cleaning, but always at a low level equal or less than the concentration of the alkali metal cleaner used. It has always been feared that such additives could carry over to contaminate the second cleaner system and not be removed to an adequate extent prior to phosphating.
  • The present invention is based on the surprising and unexpected discovery that high level additions of solvent-emulsifier to the first or only cleaning stage, and minor additions to the second cleaning stage, if present, can be used with success and can replace prewiping entirely.
  • Accordingly, the present invention provides a method in which metal articles are sprayed in at least one cleaning stage by means of an aqueous cleaning liquid containing an alkali metal cleaner and the articles are spray rinsed prior to phosphating, wherein a solvent-emulsifier is added to the cleaning liquid in the first cleaning stage at a concentration which is at least twice as high as the concentration of the alkali metal cleaner, which is present at a concentration of 1.0% or less.
  • - When there are two spray cleaning stages it is of advantage to add a small amount of solvent-emulsifier to the cleaning liquid used in the second cleaning stage.
  • The emulsifier of the solvent-emulsifier may be non-ionic, anionic or mixtures thereof.
  • Small scale tests have shown that in the first cleaning stage the solvent-emulsifier may be present in a concentration which is up to 30 times as high as the concentration of the alkali metal cleaner, without any adverse effects on the subsequent phosphating step. However, the lower the concentration of the solvent-emulsifier, the better are the economics. It is therefore preferred to operate using a concentration of the solvent-emulsifier which is about 2 to 3 times the concentration of the alkali metal cleaner.
    • EXAMPLE
  • In an automotive plant the practice was to use 5000tof solvent-emulsifier each month and it was applied manually in a prewipe operation. The first cleaner was operated at a percentage of 0.5% of cleaner at 50°C and a spray pressure of 2 Bar. The strength of the second cleaner solution was 0.3% at 55°C at a spray pressure of 2 Bar.
  • The present invention was applied to the same plant with no adverse effects on the phosphating over a period of 8 weeks. No prewipe was applied.
  • The first cleaner operated with the same alkali cleaner consisting of 0.5% by mass of a solution in water as set out below. To this was added 3.0% by mass of a solvent-emulsifier as set out below.
    • Alkali Cleaner:
  • Figure imgb0001
    • Solvent Cleaner:
  • Figure imgb0002
  • The spray pressure was 3 Bar and the temperature was kept at ambient.
  • The second cleaner operated with the same alkali cleaner at 0.3% by mass plus the same solvent-emulsifier at 0.05% by mass. The spray pressure was 2 Bar and the temperature 55°C.
  • The consumption of solvent-emulsifier was only 500 per month. In addition there was a
    considerable saving in labour and heating costs.

Claims (6)

1. A method in which metal articles are sprayed in at least one cleaning stage by means of an aqueous cleaning liquid containing an alkali metal cleaner and the articles are spray rinsed prior to phosphating, wherein a solvent-emulsifier is added to the cleaning liquid in the first cleaning stage at a concentration which is at least twice as high as the concentration of the alkali metal cleaner, which is present at a concentration of 1.0% or less.
2. A method as claimed in claim 1 in which there are at least two spray cleaning stages with a liquid containing an alkali metal cleaner.
3. A method as claimed in claim 2 in which a small amount of a solvent-emulsifier is added to the cleaning liquid used in the second cleaning stage.
4. A method as claimed in any of the preceding claims in which the cleaning liquid used in the first stage contains a solvent-emulsifier, at a concentration of up to 30 times the concentration of the alkali metal cleaner.
5. A method as claimed in any one of the preceding claims in which the cleaning liquid is sprayed at ambient temperatures.
6. A method as claimed in any one of the preceding claims in which the solvent-emulsifier contains an emulsifier which is non-ionic emulsifier an anionic emulsifier or a mixture thereof.
EP79300966A 1979-02-23 1979-05-29 Method of cleaning metals Withdrawn EP0015336A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA79884 1979-02-23
ZA790884 1979-02-23

Publications (1)

Publication Number Publication Date
EP0015336A1 true EP0015336A1 (en) 1980-09-17

Family

ID=25573963

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79300966A Withdrawn EP0015336A1 (en) 1979-02-23 1979-05-29 Method of cleaning metals

Country Status (5)

Country Link
EP (1) EP0015336A1 (en)
JP (1) JPS55114371A (en)
AU (1) AU4752879A (en)
BR (1) BR7904605A (en)
PT (1) PT69748A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996023088A1 (en) * 1995-01-24 1996-08-01 Vojcek Lorant Process for the cleaning and degreasing of solid surfaces
CN114850621A (en) * 2022-06-13 2022-08-05 张炜 Method for welding oil stain welding part

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2208524A (en) * 1936-01-06 1940-07-16 Parker Rust Proof Co Cleaning composition and process
US2298312A (en) * 1940-08-03 1942-10-13 American Chem Paint Co Method of phosphate coating ferrous metal surfaces
DE1170750B (en) * 1956-08-22 1964-05-21 Collardin Gmbh Gerhard Process to improve the non-cutting deformation of workpieces made of iron and zinc with the help of phosphate layers applied before deformation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2208524A (en) * 1936-01-06 1940-07-16 Parker Rust Proof Co Cleaning composition and process
US2298312A (en) * 1940-08-03 1942-10-13 American Chem Paint Co Method of phosphate coating ferrous metal surfaces
DE1170750B (en) * 1956-08-22 1964-05-21 Collardin Gmbh Gerhard Process to improve the non-cutting deformation of workpieces made of iron and zinc with the help of phosphate layers applied before deformation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996023088A1 (en) * 1995-01-24 1996-08-01 Vojcek Lorant Process for the cleaning and degreasing of solid surfaces
CN114850621A (en) * 2022-06-13 2022-08-05 张炜 Method for welding oil stain welding part

Also Published As

Publication number Publication date
JPS55114371A (en) 1980-09-03
PT69748A (en) 1979-07-01
AU4752879A (en) 1980-08-28
BR7904605A (en) 1981-01-21

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

Designated state(s): DE FR GB IT NL SE

17P Request for examination filed

Effective date: 19801015

STAA Information on the status of an ep patent application or granted ep patent

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18W Application withdrawn

Withdrawal date: 19801218

RIN1 Information on inventor provided before grant (corrected)

Inventor name: DARE, LUIGI