Coated body and building exterior member
To provide a coated body excellent in weather resistance and excellent also in pressure marking resistance. The coated body comprises a substrate, an undercoating film, a prescribed intermediate coating film and a top coating film formed by curing a top coating material comprising the following components (1) to (3), in this order: (1) a fluorinated polymer having hydroxy groups or carboxy groups; (2) a curing agent for curing the fluorinated polymer; and (3) a prescribed ultraviolet absorber.
1. A coated body comprising a substrate, an undercoating film, the following intermediate coating film and the following top coating film in this order,
Intermediate coating film: a coating film formed from an intermediate coating material comprising a pigment, a polyvinylidene fluoride and a (meth)acrylic resin, wherein the mass ratio of the polyvinylidene fluoride to the (meth)acrylic resin (i.e. the mass ratio of the polyvinylidene fluoride/the (meth)acrylic resin) is from 50/50 to 90/10,
Top coating film: a coating film formed by curing a top coating material comprising the following (1) to (3):
(1) a fluorinated polymer having hydroxy groups or carboxy groups, wherein the fluorinated polymer having hydroxy groups or carboxy groups comprises units based on a monomer having a hydroxy group or a monomer having a carboxy group, and the monomer having a hydroxy group is selected from the group consisting of a hydroxyalkyl vinyl ether, a hydroxyalkyl carboxylic acid vinyl ester, a hydroxyalkyl allyl ether, a hydroxyalkyl carboxylic acid allyl ester, a hydroxyalkyl (meth)acrylate,
(2) a curing agent for curing the fluorinated polymer,
(3) at least one ultraviolet absorber selected from the group consisting of an inorganic ultraviolet absorber, a salicylate-type ultraviolet absorber, a benzotriazole-type ultraviolet absorber, a hydroxyphenyl triazine-type ultraviolet absorber, a benzophenone-type ultraviolet absorber and a cyanoacrylate-type ultraviolet absorber, wherein said top coating film does not contain titanium oxide.
2. The coated body according to claim 1 , wherein the elongation of the top coating film is from 50 to 200%.
3. The coated body according to claim 1 , wherein the breaking stress of the top coating film is from 5.0 to 40.0 MPa, and the glass transition temperature of the top coating film is from −15 to 40° C.
4. The coated body according to claim 1 , wherein the fluorinated polymer comprises units based on a fluoroolefin, the units based on a monomer having a hydroxy group or a monomer having a carboxy group, and units based on a monomer having a C 2-12 chain alkyl group.
5. The coated body according to claim 1 , wherein the curing agent is a curing agent having an isocyanate group or a blocked isocyanate group.
6. The coated body according to claim 1 , wherein the fluorinated polymer comprises units based on a fluoroolefin, the units based on a monomer having a hydroxy group, and units based on a monomer having a C 2-12 chain alkyl group, and has a hydroxy value of from 20 to 200 mg KOH/g.
7. The coated body according to claim 1 , wherein the pigment contains titanium oxide.
8. The coated body according to claim 1 , wherein the undercoating film is a coating film formed from a coating material containing a (meth)acrylic resin, a polyester resin or an epoxy resin.
9. The coated body according to claim 1 , wherein the substrate is a metal plate.
10. A building exterior member comprising a coated body as defined in claim 1 .
11. The coated body according to claim 1 , wherein the fluorinated polymer comprises,
from 20 to 80 mol % of units based on a fluoroolefin,
from 0.5 to 60 mol % of group the units based on a monomer having a hydroxy group or a monomer having a carboxy group,
from 0.5 to 60 mol % of units based on a monomer having a C 2-12 chain alkyl group, and
from 0 to 30 mol % of units based on a monomer having a cyclic hydrocarbon group with at least 3 carbon atoms,
to all units in the fluorinated polymer.
12. The coated body according to claim 4 , wherein the monomer having a C 2-12 chain alkyl group is selected from the group consisting of an alkyl vinyl ether, an alkyl vinyl ester, an alkyl allyl ether, an alkyl allyl ester, and an alkyl (meth)acrylate.
13. The coated body according to claim 4 , wherein the content of the units based on a monomer having the above chain alkyl group is at least 30 mol %, to all units in the fluorinated polymer.
14. The coated body according to claim 1 , wherein the content of the ultraviolet absorber is from 0.1 to 15 mass % to the fluorinated polymer.
15. The coated body according to claim 1 , wherein the fluorinated polymer contains hydroxy groups and does not contain carboxy groups.
16. The coated body according to claim 1 , wherein the content of the ultraviolet absorber is from 12.0 to 15.0 mass % to the fluorinated polymer.