GB1558963A - Protection of metal surfaces - Google Patents

Protection of metal surfaces Download PDF

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Publication number
GB1558963A
GB1558963A GB2982475A GB2982475A GB1558963A GB 1558963 A GB1558963 A GB 1558963A GB 2982475 A GB2982475 A GB 2982475A GB 2982475 A GB2982475 A GB 2982475A GB 1558963 A GB1558963 A GB 1558963A
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United Kingdom
Prior art keywords
paste
parts
component
liquid
zinc
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
Application number
GB2982475A
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.)
Belzona Molecular Metalife Ltd
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Belzona Molecular Metalife 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 Belzona Molecular Metalife Ltd filed Critical Belzona Molecular Metalife Ltd
Priority to GB2982475A priority Critical patent/GB1558963A/en
Publication of GB1558963A publication Critical patent/GB1558963A/en
Expired 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
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/08—Anti-corrosive paints
    • C09D5/10—Anti-corrosive paints containing metal dust
    • C09D5/106—Anti-corrosive paints containing metal dust containing Zn
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
    • C09D1/02—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances alkali metal silicates
    • C09D1/04—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances alkali metal silicates with organic additives

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Paints Or Removers (AREA)

Description

(54) PROTECTION OF METAL SURFACES (71) We,BELZONA MOLECULAR METALIFE LIMITED, of Claro Road, Harrogate HG1 4AY, North Yorkshire in the County of York, a British Company, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to the protection of metal surfaces and in particular to the protection of ferrous surfaces by selective galvanic action.
Ferrous surfaces can be protected by means of galvanic action using metals which are above iron in the electrochemical series. When placed in direct contact with ferrous surfaces, these metals, which include zinc, magnesium and aluminium, will protect the surface due to the formation of a galvanic cell, whereby the protecting metal corrodes rather than the ferrous surface.
Coatings based on zinc have been used for many years to protect steel by galvanic action.
For good protection the amount of zinc in the coating should be normally at least 85% by weight of the dry film. However, the optimum level of zinc will vary according to the binder employed. The binder can be based on "organic resins" such as expoxides or polyurethanes, or on so-called "inorganic resins" such as those based on ethyl silicate or alkali metal silicates.
The ethyl silicates are classed as inorganic resins because, on curing, the resultant polymer is inorganic in nature.
Both organic and inorganic zinc coatings protect steel by galvanic action although, generally speaking, the inorganic coatings are more reactive due to the nature of the polymer in the final coating.
Known inorganic coatings are supplied as a two component pack, one component being a liquid binder and the other component being a powder which includes zinc dust. It is difficult to mix the two components due to the completely different physical nature of the components. Even when mixed the resultant composition is difficult to apply to the metal surface.
According to the present invention there is provided a two component pack for providing a protective coating to a ferrous surface, comprising a first component which includes a liquid silicate based resin and a second component which comprises a thixotropic paste containing zinc dust and a thickening agent.
Fillers and/ or extenders may be used to replace part of the zinc dust if a product with lower cathodic protection and reactivity is required.
The liquid resin binder component may contain pigments and/ or extenders, but preferably up to an amount not greater than 20% by weight.
For best results the amount of zinc should be such that there is in a dry film about 90%by weight of zinc. The amount of zinc can, however, be varied between 55 % and 95 % by weight of the dry film depending on the particular properties required for the protective film. For coatings containing a lower level of zinc, certain pigments and extenders, for instance, zinc chromate and zinc oxide, can improve the effectiveness of the coating.
Preferably the liquid resin binder has a solid content of from 15 to 50% by weight. In addition to pigments and extenders, the binder component may also include solvent in order to make the mixed composition easier to apply.
The liquid portion of the paste components can be a non-polar organic liquid, such as xylene, or a polar organic liquid, such as ketone, an ester or a glycol ether. Preferably the paste includes both a polar and a non-polar liquid.
A thickening agent, when incorporated in the paste, can be an organic or an inorganic based material. Preferred thickening agents are hydrogenated castor oils and modified clays.
A pigment, if incorporated in the paste component, is selected according to the nature of the coating required. For optimum corrosion protection, the paste should contain no fillers, extenders or pigments.
The paste component is preferably prepared by placing a portion of the liquid, preferably approximately half the liquid, in a suitable container and adding thickening agent using a high speed dispersion machine. Zinc dust is added to the resultant paste and the remaining liquid is then added to keep the paste mobile. By this method a thixotripic zinc paste can be produced in which the zinc is completely dispersed and the resultant paste has excellent storage properties.
Examples in accordance with the present invention will now be described. All parts are by weight.
Example I A two component pack in accordance with the present invention included a paste component having the following formulation: Xylene 22.5 parts Bentone (Trade Mark) 27 (a dimethyl octadecyl derivative of a magnesium montmorillonite). 1.5 parts Zinc Dust 76.0.parts The paste component was mixed with 25 parts of a liquid silicate binder and the resultant mix provided an excellent protective coating. This formulation is based on a fast drying organic liquid and is suitable for application where a rapid drying primer is required. The silicate used is a partially hydrolysed tetraethyl orthosilicate sold under the trade- mark SILESTER ZNA by Monsanto.
Example 2 A two component pack according to the present invention included a paste component having the following formulation: Ethyl Glycol Acetate 22.5 parts Bentone 27 2.5 parts Zinc Dust 75.0 parts The paste component was mixed with 25 parts of a liquid silicate binder (SILESTER ZNA). This formulation is based on a more slowly drying organic liquid and is particularly advantageous where it is desired to eliminate the problem of dry spray. This formulation also enables films of thicknesses up to 5.0 mils to be applied in a single application. The use of a more slowly drying solvent also helps to overcome the problem of mud-cracking which can be a considerable problem with zinc silicate protective coatings.
Example 3 A two component pack in accordance with the present invention included a paste component having the following formulation: Xylene 7.5 parts Ethyl Glycol Acetate 15.0 parts Bentone 27 1.5 parts Zinc Dust 76.0 parts 25 parts of liquid silicate binder (SILESTER ZNA) were added to the paste component. This formulation is based on a blend of slow and fast drying organic liquids.
Example 4 A two component pack in accordance with the present invention includes a paste component having the following composition: Zinc Dust 44.0 parts Ethyl Glycol Acetate 35.0 parts Zinc Oxide 9.0 parts Talc 15.0 parts Bentone 27 2.0 parts 30 parts of a liquid silicate binder (SILESTER ZNA) were added to the paste component. It can be seen that in the paste component the amount of zinc dust is comparatively low and zinc oxide and talc have been added as fillers.
The resultant mix provides a lower level of corrosion resistance but, being less reactive, the amount of zinc salt formed is reduced. Such reduced zinc dust formulations may be preferred where the appearance of the steel work is important.
WHAT WE CLAIM IS: 1. A two component pack for providing a protective coating to a ferrous surface, comprising a first component which includes a liquid silicate based resin and a second component which comprises a thixotropic paste containing zinc dust and a thickening agent.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. A thickening agent, when incorporated in the paste, can be an organic or an inorganic based material. Preferred thickening agents are hydrogenated castor oils and modified clays. A pigment, if incorporated in the paste component, is selected according to the nature of the coating required. For optimum corrosion protection, the paste should contain no fillers, extenders or pigments. The paste component is preferably prepared by placing a portion of the liquid, preferably approximately half the liquid, in a suitable container and adding thickening agent using a high speed dispersion machine. Zinc dust is added to the resultant paste and the remaining liquid is then added to keep the paste mobile. By this method a thixotripic zinc paste can be produced in which the zinc is completely dispersed and the resultant paste has excellent storage properties. Examples in accordance with the present invention will now be described. All parts are by weight. Example I A two component pack in accordance with the present invention included a paste component having the following formulation: Xylene 22.5 parts Bentone (Trade Mark) 27 (a dimethyl octadecyl derivative of a magnesium montmorillonite). 1.5 parts Zinc Dust 76.0.parts The paste component was mixed with 25 parts of a liquid silicate binder and the resultant mix provided an excellent protective coating. This formulation is based on a fast drying organic liquid and is suitable for application where a rapid drying primer is required. The silicate used is a partially hydrolysed tetraethyl orthosilicate sold under the trade- mark SILESTER ZNA by Monsanto. Example 2 A two component pack according to the present invention included a paste component having the following formulation: Ethyl Glycol Acetate 22.5 parts Bentone 27 2.5 parts Zinc Dust 75.0 parts The paste component was mixed with 25 parts of a liquid silicate binder (SILESTER ZNA). This formulation is based on a more slowly drying organic liquid and is particularly advantageous where it is desired to eliminate the problem of dry spray. This formulation also enables films of thicknesses up to 5.0 mils to be applied in a single application. The use of a more slowly drying solvent also helps to overcome the problem of mud-cracking which can be a considerable problem with zinc silicate protective coatings. Example 3 A two component pack in accordance with the present invention included a paste component having the following formulation: Xylene 7.5 parts Ethyl Glycol Acetate 15.0 parts Bentone 27 1.5 parts Zinc Dust 76.0 parts 25 parts of liquid silicate binder (SILESTER ZNA) were added to the paste component. This formulation is based on a blend of slow and fast drying organic liquids. Example 4 A two component pack in accordance with the present invention includes a paste component having the following composition: Zinc Dust 44.0 parts Ethyl Glycol Acetate 35.0 parts Zinc Oxide 9.0 parts Talc 15.0 parts Bentone 27 2.0 parts 30 parts of a liquid silicate binder (SILESTER ZNA) were added to the paste component. It can be seen that in the paste component the amount of zinc dust is comparatively low and zinc oxide and talc have been added as fillers. The resultant mix provides a lower level of corrosion resistance but, being less reactive, the amount of zinc salt formed is reduced. Such reduced zinc dust formulations may be preferred where the appearance of the steel work is important. WHAT WE CLAIM IS:
1. A two component pack for providing a protective coating to a ferrous surface, comprising a first component which includes a liquid silicate based resin and a second component which comprises a thixotropic paste containing zinc dust and a thickening agent.
2. A pack according to claim 1 wherein the liquid resin has a solid content of from 15 to
50% by weight of said liquid resin.
3. A pack according to claim 1 or claim 2 wherein the paste includes both a polar and a non-polar liquid.
4. A pack according to any of the preceding claims wherein the paste is prepared by adding thickening agent to a portion of a liquid which is being stirred by means of a high speed dispersion machine, adding zinc dust to the resultant paste, and adding further liquid to keep the paste mobile.
5. A pack according to claim 1 and substantially as herein described.
6. A two component pack substantially as described in any of the specific Examples.
GB2982475A 1976-07-12 1976-07-12 Protection of metal surfaces Expired GB1558963A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2982475A GB1558963A (en) 1976-07-12 1976-07-12 Protection of metal surfaces

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2982475A GB1558963A (en) 1976-07-12 1976-07-12 Protection of metal surfaces

Publications (1)

Publication Number Publication Date
GB1558963A true GB1558963A (en) 1980-01-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB2982475A Expired GB1558963A (en) 1976-07-12 1976-07-12 Protection of metal surfaces

Country Status (1)

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GB (1) GB1558963A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2478660A1 (en) * 1980-03-20 1981-09-25 Lappartient Sa Peintures H Two-part zinc silicate paint - one part contg. pigments dispersion in varnish, the other reactive silicate
GB2131822A (en) * 1982-10-28 1984-06-27 Alan Richard Parkinson Corrosion preventive composition
BE1008926A4 (en) * 1994-11-16 1996-10-01 Zingametall B V B A Method for covering metal pieces with a protective layer containing zinc

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2478660A1 (en) * 1980-03-20 1981-09-25 Lappartient Sa Peintures H Two-part zinc silicate paint - one part contg. pigments dispersion in varnish, the other reactive silicate
GB2131822A (en) * 1982-10-28 1984-06-27 Alan Richard Parkinson Corrosion preventive composition
BE1008926A4 (en) * 1994-11-16 1996-10-01 Zingametall B V B A Method for covering metal pieces with a protective layer containing zinc

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Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920712