GB2097809A - Coating metal articles - Google Patents

Coating metal articles Download PDF

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Publication number
GB2097809A
GB2097809A GB8113869A GB8113869A GB2097809A GB 2097809 A GB2097809 A GB 2097809A GB 8113869 A GB8113869 A GB 8113869A GB 8113869 A GB8113869 A GB 8113869A GB 2097809 A GB2097809 A GB 2097809A
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GB
United Kingdom
Prior art keywords
layer
coating
article
hot melt
pipe
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Withdrawn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
GB8113869A
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.)
Plascoat Systems Ltd
Original Assignee
Plascoat UK Ltd
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 Plascoat UK Ltd filed Critical Plascoat UK Ltd
Priority to GB8113869A priority Critical patent/GB2097809A/en
Publication of GB2097809A publication Critical patent/GB2097809A/en
Withdrawn legal-status Critical Current

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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
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J151/06—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond

Abstract

Metal articles, for example metal pipes, are provided with protective coatings which comprise a layer of thermoplastic hot melt adhesive containing polar groups.

Description

SPECIFICATION Improvements in coating metal articles The present invention relates to an improved coated metal article, in particular an externally coated metal pipe for use in pipe lines for carrying gas, oil or other fluids where the operating temperature can be in excess of 600C but not exceeding 950C, and to a method for coating the article.
According to a first aspect of the present invention there is provided a metal article having a protective coating thereon comprising a layer of thermoplastic hot melt adhesive containing polar groups. The coating preferably also contains in admixture with the thermoplastic hot melt adhesive a thermoplastic polymer.
The protective coating may further include a second layer comprising a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer.
According to a second aspect of the present invention there is provided a method of coating a metal article with a protective coating, comprising the steps of, (a) preheating the surface of the article to a temperature in the range of 1 500C-4000C (b) applying to the heated surface a layer of powdered thermoplastic hot melt adhesive containing polar groups.
The layer may contain in admixture with the thermoplastic hot melt adhesive a thermoplastic copolymer.
The method may further comprise applying to the first layer a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer.
The particle size of powders if preferably in the range 50-1000 microns.
The article is preferably a pipe and the metal is preferably iron, steel or brass.
According to either aspect, The thermoplastic hot melt adhesive is preferably an acrylic acid modified polypropylene or an acrylic acid modified ethylene propylene copolymer. The polar groups may be selected from the group comprising carboxyl, carbonyl, hydroxyl, amine and amide.
The second layer is preferably polypropylene, ethylene propylene copolymer or a mixture of either polypropylene or an ethylene propylene copolymer with other polyolefins. The second layer preferably contains a high level of antioxidant, preferably between 0.3-3.0% of a sterically hindered phenolic type.
The proportion of polyolefin or polyolefin mixture in the first layer is preferably in the range 0-90%.
The polyolefin in the second layer is preferably polybut-1 -ene. The proportion of polybut-1-ene is preferably in the range 5%95%.
The invention will now be described by way of an example only with reference to the accompanying drawing Figure 1 which is a diagrammatic non-scale section through a portion of steel pipe coated according to the invention.
Referring to the drawing there is shown a portion of coated steel pipe 10 comprising a steel pipe portion 1 a primer layer 12 coated onto the pipe portion 1 and a top coat 13 coated onto the primer layer 12.
The primer layer consists of a hot melt adhesive preferably propylene acrylic acid copolymer.
The top coat comprises a layer of polypropylene blended with polybut-1-ene.
EXAMPLE 1 The surface of a steel pipe 11 was cleaned by grit blasting the pipe. The pipe was then heated to about 2500C-3000C.
The heated pipe was then transferred to a coating station where it was rotated and strew coated with powdered primer of 100-400 micron size consisting of propylene acrylic acid copolymer to form a fused primer layer 1 2 about 0.25 mm thick on the pipe.
Powder polypropylene/polybut-1 -ene mixture was strew-coated onto the primer layer whilst the pipe was at a temperature of about 2500C to provide a top coat layer 13 about 2.5 mm thicl < .
After coating the pipe 10 was passed to a cooling station where it was cooled while rotating.
The coating exhibited good adhesion to the steel pipe and good resistance by means of the polypropylene based coating to damage from external sources, such as impacts or abrasion, at temperatures in excess of 60"C and up to 950C.
The polybut-1-ene afforded enhanced toughness and freedom from porosity to the coating.
EXAMPLE 2 A pipe was coated as in example 1, but with no primer layer, using a blend of polypropylene, polybut-1 -ene, polypropylene acrylic acid copolymer and a hindered phenolic antioxidant.
The coating exhibited good adhesion to the steel pipe and good resistance by means of the polypropylene based coating to damage from external sources, such as impacts or abrasion, at temperatures in excess of 600C and up to 950 C.
The polybut-1 -ene afforded enhanced toughness and freedom from porosity to the coating.
The pipe may be coated by methods other than strew coating, e.g., cascade coating (a heated pipe indexed under a vibrating mesh based hopper), tumble bed coating, or fluidised bed coating.
The top coat may be based on polypropylene, ethylene propylene copolymer, or a mixture of these with other polyolefins and modified polyolefins.
The thermoplastic hot melt adhesive should be compatible with the top coat.
1. A metal article having a protective coating thereon comprising a layer of thermoplastic hot melt adhesive containing polar groups.
2. An article as claimed in claim 1, wherein the thermoplastic hot melt adhesive is an acrylic acid modified polypropylene, or an acrylic acid
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (30)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in coating metal articles The present invention relates to an improved coated metal article, in particular an externally coated metal pipe for use in pipe lines for carrying gas, oil or other fluids where the operating temperature can be in excess of 600C but not exceeding 950C, and to a method for coating the article. According to a first aspect of the present invention there is provided a metal article having a protective coating thereon comprising a layer of thermoplastic hot melt adhesive containing polar groups. The coating preferably also contains in admixture with the thermoplastic hot melt adhesive a thermoplastic polymer. The protective coating may further include a second layer comprising a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer. According to a second aspect of the present invention there is provided a method of coating a metal article with a protective coating, comprising the steps of, (a) preheating the surface of the article to a temperature in the range of 1 500C-4000C (b) applying to the heated surface a layer of powdered thermoplastic hot melt adhesive containing polar groups. The layer may contain in admixture with the thermoplastic hot melt adhesive a thermoplastic copolymer. The method may further comprise applying to the first layer a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer. The particle size of powders if preferably in the range 50-1000 microns. The article is preferably a pipe and the metal is preferably iron, steel or brass. According to either aspect, The thermoplastic hot melt adhesive is preferably an acrylic acid modified polypropylene or an acrylic acid modified ethylene propylene copolymer. The polar groups may be selected from the group comprising carboxyl, carbonyl, hydroxyl, amine and amide. The second layer is preferably polypropylene, ethylene propylene copolymer or a mixture of either polypropylene or an ethylene propylene copolymer with other polyolefins. The second layer preferably contains a high level of antioxidant, preferably between 0.3-3.0% of a sterically hindered phenolic type. The proportion of polyolefin or polyolefin mixture in the first layer is preferably in the range 0-90%. The polyolefin in the second layer is preferably polybut-1 -ene. The proportion of polybut-1-ene is preferably in the range 5%95%. The invention will now be described by way of an example only with reference to the accompanying drawing Figure 1 which is a diagrammatic non-scale section through a portion of steel pipe coated according to the invention. Referring to the drawing there is shown a portion of coated steel pipe 10 comprising a steel pipe portion 1 a primer layer 12 coated onto the pipe portion 1 and a top coat 13 coated onto the primer layer 12. The primer layer consists of a hot melt adhesive preferably propylene acrylic acid copolymer. The top coat comprises a layer of polypropylene blended with polybut-1-ene. EXAMPLE 1 The surface of a steel pipe 11 was cleaned by grit blasting the pipe. The pipe was then heated to about 2500C-3000C. The heated pipe was then transferred to a coating station where it was rotated and strew coated with powdered primer of 100-400 micron size consisting of propylene acrylic acid copolymer to form a fused primer layer 1 2 about 0.25 mm thick on the pipe. Powder polypropylene/polybut-1 -ene mixture was strew-coated onto the primer layer whilst the pipe was at a temperature of about 2500C to provide a top coat layer 13 about 2.5 mm thicl < . After coating the pipe 10 was passed to a cooling station where it was cooled while rotating. The coating exhibited good adhesion to the steel pipe and good resistance by means of the polypropylene based coating to damage from external sources, such as impacts or abrasion, at temperatures in excess of 60"C and up to 950C. The polybut-1-ene afforded enhanced toughness and freedom from porosity to the coating. EXAMPLE 2 A pipe was coated as in example 1, but with no primer layer, using a blend of polypropylene, polybut-1 -ene, polypropylene acrylic acid copolymer and a hindered phenolic antioxidant. The coating exhibited good adhesion to the steel pipe and good resistance by means of the polypropylene based coating to damage from external sources, such as impacts or abrasion, at temperatures in excess of 600C and up to 950 C. The polybut-1 -ene afforded enhanced toughness and freedom from porosity to the coating. The pipe may be coated by methods other than strew coating, e.g., cascade coating (a heated pipe indexed under a vibrating mesh based hopper), tumble bed coating, or fluidised bed coating. The top coat may be based on polypropylene, ethylene propylene copolymer, or a mixture of these with other polyolefins and modified polyolefins. The thermoplastic hot melt adhesive should be compatible with the top coat. CLAIMS
1. A metal article having a protective coating thereon comprising a layer of thermoplastic hot melt adhesive containing polar groups.
2. An article as claimed in claim 1, wherein the thermoplastic hot melt adhesive is an acrylic acid modified polypropylene, or an acrylic acid modified ethylene propylene copolymer.
3. An particle as claimed in claim 1 or 2, wherein the polar groups are selected from the group comprising carboxyl, carbonyl, hydroxyl, amine and amide.
4. An article as claimed in claim 1, 2 or 3, wherein the proportion of polyolefin or polyolefin mixture in the first layer is in the range 0-90%.
5. An article as claimed in any preceding claim, wherein the coating aiso contains, in admixture with the thermoplastic hot melt adhesive, a thermoplastic polymer.
6. An article as claimed in any preceding claim, wherein the coating further includes a second layer comprising a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer.
7. An article as claimed in claim 6, wherein the second layer is polypropylene, ethylene propylene copolymer or a mixture of either polypropylene or an ethylene propylene copolymer with other polyolefins.
8. An article as claimed in any preceding claim, wherein the second layer contains a high level of antioxidant.
9. An article as claimed in claim 8, wherein the second layer contains between 0.33.0% of a sterically hindered phenolic type antioxidant.
10. An article as claimed in claim 6, or claim 6 in combination with any of claims 7 to 9, wherein the polyolefin in the second layer is polybut-1 -ene.
1 An article as claimed in claim 10, wherein the proportion of polybut-1-ene is in the range 5%95%.
12. An article as claimed in any preceding claim, wherein the metal is-iron. steel or brass.
13. An article as claimed in any preceding claim, which comprises a metal pipe, tank, plate or sheet.
14. A method of coating a metal article with a protective coating, comprising the steps of, (a) preheating the surface of the article to a temperature in the range of 1 50 C 400 C (b) applying to the heated surface a layer of powdered thermoplastic hot melt adhesive containing polar groups.
1 5. A method as claimed in claim 14, wherein the layer contains, in admixture with the thermoplastic hot melt adhesive, a thermoplastic polymer.
16. A method as claimed in claim 14 or 15, further comprising applying to the first layer a second layer of a thermoplastic material compatible with the thermoplastic hot melt adhesive or mixture of the first layer.
17. A method as claimed in any of claims 14 to 16, wherein the powder particle size is in the range 50-1000 microns.
18. A method as claimed in any of claims 14 to 17, wherein the thermoplastic hot melt adhesive is an acrylic acid modified polypropylene, or an acrylic acid modified ethylene propylene copolymer.
19. A method as claimed in any of claims 14 to 18, wherein the polar groups are selected from the group comprising carboxyl, carbonyl, hydroxyl, amine and amide.
20. A method as claimed in any of claims 14 to 1 9, wherein the proportion of polyolefin or polyolefin mixture in the first layer is in the range 0-90%.
21. A method as claimed in claim 16, or claim 1 6 in combination with any of claims 1 7 to 20, wherein the second layer is polypropylene, ethylene propylene copolymer or a mixture of either polypropylene or an ethylene propylene copolymer with other polyolefins.
22. A method as claimed in claim 16, or claim 16 in combination with any of claims 17 to 21, wherein the second layer contains a high level of antioxidant.
23. A method as claimed in claim 22, wherein the second layer contains between 0.33.0% of a sterically hindered phenolic type antioxidant.
24. A method as claimed in claim 16, or claim 1 6 in combination with any of claims 17 to 23, wherein the polyolefin in the second layer is polybut-1 -ene.
25. A method as claimed in claim 24, wherein the proportion of polybut-1 -ene is in the range 5%~95%.
26. A method as claimed in any of claims 14 to 25, wherein the metal article is iron, steel or brass.
27. A method as claimed in any of claims 14 to 26, wherein the metal article comprises a metal pipe, tank, plate or sheet.
28. Metal articles having protective coatings thereon, substantially as hereinbefore described.
29. A metal article having a protective coating thereon substantially as hereinbefore described with reference to Example 1.
30. A metal article having a protective coating thereon substantially as hereinbefore described with reference to Example 2.
GB8113869A 1981-05-06 1981-05-06 Coating metal articles Withdrawn GB2097809A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8113869A GB2097809A (en) 1981-05-06 1981-05-06 Coating metal articles

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8113869A GB2097809A (en) 1981-05-06 1981-05-06 Coating metal articles

Publications (1)

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GB2097809A true GB2097809A (en) 1982-11-10

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2166065A (en) * 1984-10-27 1986-04-30 Webco Ltd Insulated pipeline
GB2185046A (en) * 1985-11-29 1987-07-08 Square Grip Ltd Concrete reinforcing elements allowing for relative movement between concrete and element
EP0462680A2 (en) * 1985-03-19 1991-12-27 Mitsui Petrochemical Industries, Ltd. Olefin polymer composition and laminated structure including said composition as adhesive layer
WO1994010240A1 (en) * 1992-10-30 1994-05-11 Shell Oil Company Polyolefin compositions
EP0609569A2 (en) * 1993-01-21 1994-08-10 Mitsubishi Jukogyo Kabushiki Kaisha Polypropylene lining
GB2364659A (en) * 2000-06-10 2002-02-06 Plascoat Systems Ltd Method of coating an underbody of a vehicle
CN106114603A (en) * 2016-07-23 2016-11-16 上海招博塑料制品有限公司 A kind of vehicle steering with dual density EPP structure and manufacturing process thereof

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2166065A (en) * 1984-10-27 1986-04-30 Webco Ltd Insulated pipeline
EP0462680A2 (en) * 1985-03-19 1991-12-27 Mitsui Petrochemical Industries, Ltd. Olefin polymer composition and laminated structure including said composition as adhesive layer
EP0462680A3 (en) * 1985-03-19 1992-11-25 Mitsui Petrochemical Industries, Ltd. Olefin polymer composition and laminated structure including said composition as adhesive layer
GB2185046A (en) * 1985-11-29 1987-07-08 Square Grip Ltd Concrete reinforcing elements allowing for relative movement between concrete and element
WO1994010240A1 (en) * 1992-10-30 1994-05-11 Shell Oil Company Polyolefin compositions
EP0609569A2 (en) * 1993-01-21 1994-08-10 Mitsubishi Jukogyo Kabushiki Kaisha Polypropylene lining
EP0609569A3 (en) * 1993-01-21 1994-12-21 Mitsubishi Heavy Ind Ltd Polypropylene lining.
US5677378A (en) * 1993-01-21 1997-10-14 Mitsubishi Jukogyo Kabushiki Kaisha Polypropylene lining
US5677377A (en) * 1993-01-21 1997-10-14 Mitsubishi Jukogyo Kabushiki Kaisha Polypropylene lining
CN1129639C (en) * 1993-01-21 2003-12-03 三菱重工业株式会社 Polypropylene lining
GB2364659A (en) * 2000-06-10 2002-02-06 Plascoat Systems Ltd Method of coating an underbody of a vehicle
CN106114603A (en) * 2016-07-23 2016-11-16 上海招博塑料制品有限公司 A kind of vehicle steering with dual density EPP structure and manufacturing process thereof

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