Alkyl silicate paint compositions with improved cracking resistance
The present application discloses an acidic-stabilized alkyl silicate composition comprising 0.5-30% by solids volume of inorganic fibers, wherein the fibers have (i) an average length of 25-250 μm and an average thickness of 1-50 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5; and (ii) a specific surface area (BET) of 0.01-6 m 2 /g. A corresponding acidic-stabilized alkyl silicate composition comprising zinc and inorganic fibers, wherein the zinc constitutes 50-95% by solids weight of the total composition, and the fibers constitutes 0.5-30% by solids volume of the non-zinc fraction of the composition, is also disclosed. The application further discloses a method for the establishment of a crack resistant alkyl silicate paint coat by applying one of the compositions to a metal surface.
1. An acidic-stabilised alkyl silicate composition comprising 0.5-30% by solids volume of inorganic fibres,
said fibres having
(i) an average length of 25-250 μm and an average thickness of 1-50 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5; and
(ii) a specific surface area (BET) of 0.01-6 m 2 /g.
2. The composition according to claim 1 , wherein the fibres are mineral fibres.
3. The composition according to claim 1 , wherein the fibres have a pH of 8.0-11.0.
4. The composition according to claim 1 , wherein the fibres have a silicium (SiO 2 ) content of 30-60% w/w, a combined calcium (CaO) and magnesium (MgO) content of 20-50% w/w, an aluminium (Al 2 O 3 ) content of 0.1-30% w/w, an iron (Fe 2 O 3 /FeO) content of up to 10% w/w, and a combined potassium (K 2 O) and sodium (Na 2 O) content of below 8% w/w.
5. The composition according to claim 1 , wherein the fibres have a specific surface area (BET) of 0.05-4.0 m 2 /g.
6. The composition according to claim 1 , which comprises 2-30% by solids volume of the fibres.
7. The composition according to claim 1 , wherein the degree of pre-hydrolysis of the alkyl silicate resin is more than 50%.
8. The composition according to claim 1 , wherein the fibres have an average length of 50-250 μm, an average thickness of 2-20 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5.
9. The composition according to claim 1 , wherein the weight ratio of said fibres to the alkyl silicate
resin is at least 20:100.
10. The composition according to claim 1 which comprises 1-25% by solids volume of mineral fibres,
said fibres having
(i) an average length of 50-250 μm, an average thickness of 2-20 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5;
(ii) a specific surface area (BET) of 0.05-4.0 m 2 /g;
(iii) a silicium (SiO 2 ) content of 30-60% w/w, a combined calcium (CaO) and magnesium (MgO) content of 20-50% w/w, an aluminium (Al 2 O 3 ) content of 0.1-30% w/w, an iron (Fe 2 O 3 /FeO) content of up to 10% w/w, and a combined potassium (K 2 O) and sodium (Na 2 O) content of below 8% w/w;
the weight ratio of said fibre to the alkyl silicate resin being at least 20:100.
11. The composition according to claim 10 , wherein the fibres have a pH of 8.5-10.5.
12. An acidic-stabilised alkyl silicate composition comprising zinc and inorganic fibres, the zinc constituting 50-95% by solids weight of the total composition, and the fibres constituting 0.5-30% by solids volume of the non-zinc fraction of the composition,
said fibres having
(i) an average length of 25-250 μm and an average thickness of 1-50 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5; and
(ii) a specific surface area (BET) of 0.01-6 m 2 /g.
13. The composition according to claim 12 which comprises 2-20% by solids volume of the non-zinc fraction of the composition of the fibres.
14. The composition according to claim 12 , wherein said fibres having
(i) an average length of 50-250 μm, an average thickness of 2-20 μm, and a ratio between the average length and the average thickness (aspect ratio) of at least 5;
(ii) a specific surface area (BET) of 0.05-4.0 m 2 /g; and
(iii) a silicium (SiO 2 ) content of 30-60% w/w, a combined calcium (CaO) and magnesium (MgO) content of 20-50% w/w, an aluminium (Al 2 O 3 ) content of 0.1-30% w/w, an iron (Fe 2 O 3 /FeO) content of up to 10% w/w, and a combined potassium (K 2 O) and sodium (Na 2 O) content of below 8% w/w;
the weight ratio of said fibre to the alkyl silicate resin being at least 20:100.
15. A method for the establishment of a crack resistant alkyl silicate paint coat, said method comprising the step of applying a composition as defined in claim 1 to a metal surface.
16. A method for the establishment of a crack resistant alkyl silicate paint coat, said method comprising the step of applying a composition as defined in claim 12 to a metal surface.