Dry powder thermosetting resin composition
The present invention discloses a dry powder composition comprising a thermosetting resin in particulate form, wherein the dry powder composition has a particle size measured according to ISO 13320 (2009) characterized by a D v90 of 50 μm or lower, a D v50 in the range of 5.1 to 12.5 μm, and a ratio of Dv 90 - Dv 10 Dv 50 in the range of 1.5 to 4.2. The present invention also discloses processes for preparing the dry powder using jet milling, and processes of applying the dry powder composition to a metal surface. Furthermore, the present invention discloses the uses of the dry powder composition as a bonding material or as an adhesion promoter in a polymer compound.
1. A dry powder composition comprising a thermosetting resin in particulate form, wherein the dry powder composition has a particle size measured according to ISO 13320 (2009) characterized by
a D v90 of 50 μm or lower,
a D v50 in the range of 5.1 to 12.5 μm, and
a ratio of
Dv
90
-
Dv
10
Dv
50
in the range of 1.5 to 4.2.
2. The dry powder composition according to claim 1 , wherein the dry powder composition has a particle size D v90 measured according to ISO 13320 (2009) of 45 μm or lower.
3. The dry powder composition according to claim 1 , wherein the dry powder composition has a particle size D v50 measured according to ISO 13320 (2009) in the range of 6 to 12 μm.
4. The dry powder composition according, to claim 1 , wherein the dry powder composition has a ratio of
Dv
90
-
Dv
10
Dv
50
in the range of 2.0 to 3.8.
5. The dry powder composition according claim 1 , wherein the dry powder composition has a particle size D v99 measured according to ISO 13320 (2009) of 90 μm or lower.
6. The dry powder composition according to claim 1 , wherein the thermosetting resin is a phenolic resin.
7. The dry powder composition according to claim 1 , wherein the dry powder composition further comprises a curative and at least one inorganic particulate material.
8. The dry powder composition according to claim 7 , wherein the curative is selected from the group consisting of hexamethylenetetramine and hexamethoxymethylmelamine.
9. The dry powder composition according to claim 7 , wherein the inorganic particulate material is selected from a group consisting of anti-caking additives, anti-corrosive pigments and inorganic fillers.
10. The dry powder composition according to claim 1 , wherein the dry powder composition comprises, based on the total weight of the dry powder composition
thermosetting resin in an amount of 60 to 90%,
anti-caking additive in an amount of 1 to 10% by weight,
curative in an amount of 1 to 10% by weight,
anti-corrosive pigments in an amount of 5 to 25% by weight, and
optionally inorganic filler in an amount of 0 to 15% by weight.
11. The dry powder composition according to claim 10 , wherein the anti-caking additive is silica.
12. The dry powder composition according to claim 10 , wherein the anti-corrosive pigment is selected from a group consisting of zinc oxide, zinc phosphate, titanium dioxide, aluminum triphosphate and a combination thereof.
13. The dry powder composition according to claim 10 , wherein the inorganic filler is selected from a group consisting of carbon black, clay, CaCO 3 and a combination thereof.
14. A bonding material selected from a group consisting of coating, primer, adhesive and adhesion promoter comprising the dry powder composition of claim 1 .
15. An article selected from the group consisting of a brake pad and a brake shoe comprising the dry powder composition of claim 1 .
16. A rubber compound comprising the dry powder composition of claim 1 .
17. A process for preparing the dry powder composition according to claim 1 , the process comprising the steps:
(i) providing a precursor composition comprising a thermosetting resin in particulate form, and
(ii) jet milling the precursor composition in a the jet mill until a particle size D v90 measured according to ISO 13320 (2009) of 50 μm or lower is reached.
18. The process according to claim 17 , wherein the jet milling is carried out until a particle size D v50 measured according to ISO 13320 (2009) in the range of 5.1 to 12.5 μm is reached.
19. The process according to claim 17 , wherein the jet mill comprises a classifier wheel.
20. A process of applying a dry powder composition to a metal surface, the process comprising the step:
(i) applying the dry powder composition according to claim 1 onto a metal surface by means of electrostatic spraying or fluidized bed dipping.