CA1108019A - Method of internally coating steel drums - Google Patents
Method of internally coating steel drumsInfo
- Publication number
- CA1108019A CA1108019A CA283,325A CA283325A CA1108019A CA 1108019 A CA1108019 A CA 1108019A CA 283325 A CA283325 A CA 283325A CA 1108019 A CA1108019 A CA 1108019A
- Authority
- CA
- Canada
- Prior art keywords
- coating
- drum
- spray
- shell
- iron phosphate
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
- B05D7/227—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of containers, cans or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
- B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field
- B05D1/06—Applying particulate materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2350/00—Pretreatment of the substrate
- B05D2350/10—Phosphatation
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Paints Or Removers (AREA)
- Electrostatic Spraying Apparatus (AREA)
Abstract
Title of the Invention METHOD OF INTERNALLY COATING STEEL DRUMS
Abstract of the Disclosure Drum shells, lids and filling hole covers, prior to the assembly of these parts to make steel drums, are pre-treated by spraying with an alkaline solution, iron phosphate and thereafter with a standard rust inhibitor, and the interiors of the drum parts are coated by electro-static spray application with a thermosetting epoxy-based powder to a critical thickness which eliminates subsequent cracking and subsequent vulnerability to destructive substances such as tomato paste and other more corrosive chemicals. The drum parts are preheated prior to the application of the powder to accelerate the fusion of the powder particle coating as well as reduce the associated material application problems. After application of the powder to the container interiors, the components are again subjected to oven temperatures to set and cure the coating.
Abstract of the Disclosure Drum shells, lids and filling hole covers, prior to the assembly of these parts to make steel drums, are pre-treated by spraying with an alkaline solution, iron phosphate and thereafter with a standard rust inhibitor, and the interiors of the drum parts are coated by electro-static spray application with a thermosetting epoxy-based powder to a critical thickness which eliminates subsequent cracking and subsequent vulnerability to destructive substances such as tomato paste and other more corrosive chemicals. The drum parts are preheated prior to the application of the powder to accelerate the fusion of the powder particle coating as well as reduce the associated material application problems. After application of the powder to the container interiors, the components are again subjected to oven temperatures to set and cure the coating.
Description
Related Application Copending Canadian application Sexial No. 283,326, filed July 22, 1977 and issued to Canadian Patent No. 1,084,698 on September 2, 1980 entitled "Rotator and Coater System for Drum Shells" discloses the preferred mechanical system for hand-lin~ and rotating the drum shells during the application of the powder coating. As disclosed therein, the drum shells are spun at about 100 r.p.m. with their axes horizontally disposed while the powder coating is applied, and the spray applicator head is moved through the shell and then back through it while the powder, charged negatively to a voltage of about -90 kv, is being spray-applied. The present method invention does not, however, require for its practice drum shell spinning or a~ial reciprocation of the spray applicator.
~`;' ' .
.
Related Patents and Publications The subject method employs a Ransburg-type applicating : s~stem which operates according to the old and well-known electrostatic principle of applying an elec~rostatic charge to the powder particles and applying the charged particles to the grounded shali!lid and ~illi~g hole cover partsO Exemplary Ran~burg-type application systems are sho~n and d~6cribed in ~ansburg~ et al. 2,463,422, Ransburg, et al. 2,509,448, and ~ansburg 2,567,781, and reference thereto may be had for a ) description o the principles involved and the operational detail tha~ may be employed.
Summar~ of the Invention The essential object and advantage of the invention is to provide a method ox coating the inside surfaces o~ preheated steel drum parts with an epoxy type of resinous coating ~o that the coating is i~pervious to attack by highly corrosive substancss, handling stresses and strains, and other conditions which tend to break down or rupture such coatings.
Descrip~ion of the Invention 0 The subject method of coating tha drum ~hells, lid~
and covers includes the ollowing steps:
1. Cleaning by abrasion
~`;' ' .
.
Related Patents and Publications The subject method employs a Ransburg-type applicating : s~stem which operates according to the old and well-known electrostatic principle of applying an elec~rostatic charge to the powder particles and applying the charged particles to the grounded shali!lid and ~illi~g hole cover partsO Exemplary Ran~burg-type application systems are sho~n and d~6cribed in ~ansburg~ et al. 2,463,422, Ransburg, et al. 2,509,448, and ~ansburg 2,567,781, and reference thereto may be had for a ) description o the principles involved and the operational detail tha~ may be employed.
Summar~ of the Invention The essential object and advantage of the invention is to provide a method ox coating the inside surfaces o~ preheated steel drum parts with an epoxy type of resinous coating ~o that the coating is i~pervious to attack by highly corrosive substancss, handling stresses and strains, and other conditions which tend to break down or rupture such coatings.
Descrip~ion of the Invention 0 The subject method of coating tha drum ~hells, lid~
and covers includes the ollowing steps:
1. Cleaning by abrasion
2. Washing
3. Rinsing
4. Iron phosphate application
5. Rinsing
6. Rust inhibitor application
7~ Preheating Il ' ~
8. Powder coating application
9. Heati~g to set re5in First, the drum components are cleaned and abraded by sho~-blasting with small abrasive grit.to provide anchor patterns S in the metal or the a~choring o~ the sub~e~uently applied powder.
The drum parts are the~ spray-wa~hed with water o about 160 F. containin~ a sma~l amount o~ alkali, eOg., 1~7% by wei~ht o~ al~ali.
Next, the drum parts are spray-rinsed i~ water at about ~0 ~ room ~emperature.
The part~ are then sprayed with an iron phosphate solution of, ~or example, 4.2% by weight of the phosphate in water, the solution being warm, eOg., 150 F. Thi~ i~ an important step in the process and it serves the purpo~e o~ pro-LS viding a primer coating which serves to adhera the epoxy coating to thQ metal with optimum holdlng powex.
Tha parts are then again spray rinsed with water at about room temperature.
Next, the par~s are spraye~ wi~h a rust inhibitor o solution, ~or example, a 0.3/0 by wei~ht 801ution 0~ ~hromia acid in water, the solution being at about 140 F.
The dr-um parts are then heated u~ti~ th~ir surace tempexatuxe reache~ about 200 F., the opexative range being from about 180 to about 220 F.
,5 Immediately after reaching the temperature o~ about 200 F~ or 180 - 220 F., the powder coating i5 ~pxay applied through a ~onventional Ransburg type o electrostatic ~pray applicator. At the temperatura o the metal parts, the epoxy , l, ?ow~er par~icles fuse directl~ to the metal and to ~ach otner to begin the cross-linki~g process neces~ary to form a pinhole-fr~e co~ting of 1.5 - 3.0 mil~ in thic~ness. The preferred thic~;ness is 2.0 - 2.5 mils. For example, under tomato paste handl`ins conditions a coating thic~ness in excess of 3.0 mil~
leads to rupture or cracking of the coating, particularly on the s~rfac~ ~f the filling h~le cover, while a coating of less than .
1.5 mils is vulnerable to penetra~ion ~y the food acid o~ the ~omato paste under the stress and strains of drum handling~
~he preerred class of epoxy resin powders for ~se in the subject process i9 that of the diglycidal etherq of bisphenol-A resins (DGEsA). Of the~e, those compoun~ed with aromatic amine, Lewis acid and acid anhydride curing agents are preferred. The .qelected powder should be ree flowing, having lr> a particle size range o~ 20 - 150 microns and pre~erably 30 ~ 70 :~
micron~, and have a melting point within ~he range of 180~220 F~
`A fully satisactory epoxy powder coating having such proper~ies :
and characteristics is the 531-7076 gra~e o Du Pont Company~
. powder coatings marketed under the trade mark "FLINTFLEX".
~0 Next, to set and cure the resin, the drum part~ are heated to a metal surface temperature of about 400 F., i.e., from àbout 3~0 F. to about 420 F., or about SLX minute~ e~, within a range o 5 - 12 minutes.
. Assembled drums, the parts o~ which have been treated as described above, may safely be used without deterioration of the dru~s or contents in shipment, or in storage for extended periods. Such assembled drums are there~ore particularly useful for the handling and storage of tomato paste, cherries, olives and other food products which have a gxeat potential '~r 3Q corroding and destroyin~ ~teel container~
~ 4 .
,`. ~
The drum parts are the~ spray-wa~hed with water o about 160 F. containin~ a sma~l amount o~ alkali, eOg., 1~7% by wei~ht o~ al~ali.
Next, the drum parts are spray-rinsed i~ water at about ~0 ~ room ~emperature.
The part~ are then sprayed with an iron phosphate solution of, ~or example, 4.2% by weight of the phosphate in water, the solution being warm, eOg., 150 F. Thi~ i~ an important step in the process and it serves the purpo~e o~ pro-LS viding a primer coating which serves to adhera the epoxy coating to thQ metal with optimum holdlng powex.
Tha parts are then again spray rinsed with water at about room temperature.
Next, the par~s are spraye~ wi~h a rust inhibitor o solution, ~or example, a 0.3/0 by wei~ht 801ution 0~ ~hromia acid in water, the solution being at about 140 F.
The dr-um parts are then heated u~ti~ th~ir surace tempexatuxe reache~ about 200 F., the opexative range being from about 180 to about 220 F.
,5 Immediately after reaching the temperature o~ about 200 F~ or 180 - 220 F., the powder coating i5 ~pxay applied through a ~onventional Ransburg type o electrostatic ~pray applicator. At the temperatura o the metal parts, the epoxy , l, ?ow~er par~icles fuse directl~ to the metal and to ~ach otner to begin the cross-linki~g process neces~ary to form a pinhole-fr~e co~ting of 1.5 - 3.0 mil~ in thic~ness. The preferred thic~;ness is 2.0 - 2.5 mils. For example, under tomato paste handl`ins conditions a coating thic~ness in excess of 3.0 mil~
leads to rupture or cracking of the coating, particularly on the s~rfac~ ~f the filling h~le cover, while a coating of less than .
1.5 mils is vulnerable to penetra~ion ~y the food acid o~ the ~omato paste under the stress and strains of drum handling~
~he preerred class of epoxy resin powders for ~se in the subject process i9 that of the diglycidal etherq of bisphenol-A resins (DGEsA). Of the~e, those compoun~ed with aromatic amine, Lewis acid and acid anhydride curing agents are preferred. The .qelected powder should be ree flowing, having lr> a particle size range o~ 20 - 150 microns and pre~erably 30 ~ 70 :~
micron~, and have a melting point within ~he range of 180~220 F~
`A fully satisactory epoxy powder coating having such proper~ies :
and characteristics is the 531-7076 gra~e o Du Pont Company~
. powder coatings marketed under the trade mark "FLINTFLEX".
~0 Next, to set and cure the resin, the drum part~ are heated to a metal surface temperature of about 400 F., i.e., from àbout 3~0 F. to about 420 F., or about SLX minute~ e~, within a range o 5 - 12 minutes.
. Assembled drums, the parts o~ which have been treated as described above, may safely be used without deterioration of the dru~s or contents in shipment, or in storage for extended periods. Such assembled drums are there~ore particularly useful for the handling and storage of tomato paste, cherries, olives and other food products which have a gxeat potential '~r 3Q corroding and destroyin~ ~teel container~
~ 4 .
,`. ~
Claims (7)
1. A method for protectively coating the inside surfaces of a steel drum shell and its related lid and filling hole cover to render the drum suitable for use as a container for tomato paste comprising applying a primer coating of iron phosphate thereto, heating said surfaces to a temperature of 180 - 220 degrees F, electrostatically spray-coating said heated surfaces with a therosetting epoxy resin powder adapted to melt and fuse thereto at said temperature and building up said fused coating to a thickness of 1.5-3.0 mils, and heating said surfaces to a temperature of from about 390 degrees F to about 420 degrees F for a period of 5-12 minutes to set and cure said fused coating.
2. The method of Claim 1, said epoxy resin being of the diglycidyl ether of bisphenol A type containing a curing agent selected from the group consisting of aromatic amines, Lewis acids and acid anhydrides.
3. The method of Claim 1, wherein said resin powder is spray-coated onto the inside surfaces of the drum shell in a radial spray pattern which is moved progressively along the length of the drum shell.
4. The method of Claim 1, wherein said drum shell is rotated while being spray-coated with said resin powder.
5. The method of Claim 1 wherein said shell and its related lid and filling hole cover are subjected to an alkaline wash and water rinse prior to applying said primer coating of iron phosphate.
6. The method of Claim 1 wherein said shell and its related lid and cover are spray-rinsed with water after applying said primer coating of iron phosphate thereto.
7, The method of Claim 1 wherein a rust inhibitor is applied to said shell, and its related lid and cover after said primer coating of iron phosphate has been applied.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US75934277A | 1977-01-14 | 1977-01-14 | |
| US759,342 | 1977-01-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1108019A true CA1108019A (en) | 1981-09-01 |
Family
ID=25055300
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,325A Expired CA1108019A (en) | 1977-01-14 | 1977-07-22 | Method of internally coating steel drums |
Country Status (13)
| Country | Link |
|---|---|
| JP (1) | JPS5388839A (en) |
| AU (1) | AU509790B2 (en) |
| BE (1) | BE859197A (en) |
| BR (1) | BR7707935A (en) |
| CA (1) | CA1108019A (en) |
| DE (1) | DE2743379C3 (en) |
| FR (1) | FR2377236A1 (en) |
| GB (1) | GB1552210A (en) |
| IL (1) | IL53124A (en) |
| IT (1) | IT1087186B (en) |
| MX (1) | MX148207A (en) |
| NL (1) | NL172730C (en) |
| PT (1) | PT67231B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4285783A (en) * | 1979-07-06 | 1981-08-25 | Metropolitan Wire Corporation | Coating for metal shelving and method of applying same |
| DE4333859C2 (en) * | 1993-10-05 | 1998-02-19 | Niederrheinische Blechwarenfab | Process for painting the inner surfaces of tinplate containers and system for carrying out the process |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3260611A (en) * | 1963-02-13 | 1966-07-12 | Polymer Corp | Coating method |
| GB1156776A (en) * | 1966-06-20 | 1969-07-02 | Price Co H C | Method and Apparatus for Coating Elongate Members such as Pipes. |
| DE1816330A1 (en) * | 1968-12-21 | 1970-06-25 | Metallgesellschaft Ag | Adhesive polyamide coatings, resistant to hot - water, on metal objects |
| FR2331624A1 (en) * | 1975-11-13 | 1977-06-10 | Delhomme Jacques | Long life protective coating for transformer tanks - using phosphate coating, then electrostatic spraying of powdered plastic |
-
1977
- 1977-07-22 CA CA283,325A patent/CA1108019A/en not_active Expired
- 1977-09-05 AU AU28556/77A patent/AU509790B2/en not_active Expired
- 1977-09-27 DE DE19772743379 patent/DE2743379C3/en not_active Expired
- 1977-09-29 BE BE181306A patent/BE859197A/en not_active IP Right Cessation
- 1977-10-03 FR FR7729633A patent/FR2377236A1/en active Granted
- 1977-10-13 IL IL5312477A patent/IL53124A/en unknown
- 1977-10-13 NL NL7711233A patent/NL172730C/en not_active IP Right Cessation
- 1977-10-18 IT IT2873377A patent/IT1087186B/en active
- 1977-11-02 PT PT6723177A patent/PT67231B/en unknown
- 1977-11-29 BR BR7707935A patent/BR7707935A/en unknown
-
1978
- 1978-01-13 MX MX17204578A patent/MX148207A/en unknown
- 1978-01-13 JP JP263778A patent/JPS5388839A/en active Pending
- 1978-01-16 GB GB162478A patent/GB1552210A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| AU2855677A (en) | 1979-03-15 |
| NL7711233A (en) | 1978-07-18 |
| GB1552210A (en) | 1979-09-12 |
| BR7707935A (en) | 1978-09-05 |
| FR2377236A1 (en) | 1978-08-11 |
| DE2743379A1 (en) | 1978-07-20 |
| NL172730B (en) | 1983-05-16 |
| PT67231A (en) | 1977-12-01 |
| FR2377236B1 (en) | 1982-12-31 |
| NL172730C (en) | 1983-10-17 |
| PT67231B (en) | 1979-04-13 |
| IT1087186B (en) | 1985-05-31 |
| AU509790B2 (en) | 1980-05-22 |
| JPS5388839A (en) | 1978-08-04 |
| DE2743379B2 (en) | 1980-06-26 |
| IL53124A (en) | 1980-05-30 |
| BE859197A (en) | 1978-01-16 |
| MX148207A (en) | 1983-03-25 |
| DE2743379C3 (en) | 1981-02-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19980901 |