Fin material for heat exchanger, and heat exchanger

Abstract

A heat-exchanger fin material which has a substrate composed of aluminum and a coating film formed on the substrate. The coating film is composed of a one-layered or two or more-layered coating and has a hydrophilic colored coating on its outermost surface. The hydrophilic colored coating contains an acrylic-modified epoxy resin (A), a melamine resin (B), a perfluoroalkyl group-containing alcohol resin (C), and a pigment (D). The content of the pigment (D) in the hydrophilic colored coating is 1 to 80 mg/m 2 . The water-contact angle of the hydrophilic colored coating is 20° or less. The elution ratio of the hydrophilic colored coating into running water is 1 mass % or less after an immersion test in which the heat-exchanger fin material is immersed in running water with a flow rate of 5 L/hour for 24 hours. A heat exchanger which includes a fin composed of the aforesaid heat-exchanger fin material.

1 . A heat-exchanger fin material comprising:
 a substrate composed of aluminum; and   a coating film formed on the substrate and composed of a one-layered or two or more-layered coating;   wherein the coating film has a hydrophilic colored coating on its outermost surface,   the hydrophilic colored coating contains an acrylic-modified epoxy resin (A), a melamine resin (B), a perfluoroalkyl group-containing alcohol resin (C), and a pigment (D),   the content of the pigment (D) in the hydrophilic colored coating is 1 to 80 mg/m 2 ,   the water-contact angle of the hydrophilic colored coating is 20° or less, and   the elution ratio of the hydrophilic colored coating into running water is 1 mass % or less after an immersion test in which the heat-exchanger fin material is immersed in running water with a flow rate of 5 L/hour for 24 hours.   
     
     
         2 . The heat-exchanger fin material according to  claim 1 , wherein the color fading degree of the hydrophilic colored coating after the immersion test is indicated as (ΔL, Δa, Δb)=(±2.5, ±1.0, ±1.0) in a Lab color specification system. 
     
     
         3 . The heat-exchanger fin material according to  claim 1 , wherein the hydrophilic colored coating contains 45 to 65 parts by mass of the acrylic modified epoxy resin (A) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         4 . The heat-exchanger fin material according to  claim 1 , wherein the hydrophilic colored coating contains 2 to 13 parts by mass of the melamine resin (B) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         5 . The heat-exchanger fin material according to  claim 1 , wherein the ratio of the content of the melamine resin (B) to the content of the acrylic-modified epoxy resin (A) in the hydrophilic colored coating is 0.03 to 0.25 in terms of mass ratio. 
     
     
         6 . The heat-exchanger fin material according to  claim 1 , wherein the hydrophilic colored coating contains 30 to 50 parts by mass of the perfluoroalkyl group-containing alcohol resin (C) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         7 . The heat-exchanger fin material according to  claim 1 , wherein the ratio of the content of the perfluoroalkyl group-containing alcohol resin (C) to the content of the acrylic-modified epoxy resin (A) in the hydrophilic colored coating is 5/14 to 11/8 in terms of mass ratio. 
     
     
         8 . The heat-exchanger fin material according to  claim 1 , wherein the ratio of the content of the perfluoroalkyl group-containing alcohol resin (C) to the content of the melamine resin (B) in the hydrophilic colored coating is 3/1 to 10/1 in terms of mass ratio. 
     
     
         9 . The heat-exchanger fin material according to  claim 1 , wherein the hydrophilic colored coating further contains at least one of an antibacterial agent and an antifungal agent. 
     
     
         10 . The heat-exchanger fin material according to  claim 1 , wherein the coating film comprises a corrosion resistant coating between the hydrophilic colored coating and the substrate, the corrosion resistant coating containing at least one kind of resin selected from the group consisting of acrylic-based resins, epoxy-based resins, urethane-based resins, and ester-based resins. 
     
     
         11 . A heat exchanger comprising:
 a fin composed of the heat-exchanger fin material according to  claim 1 .   
     
     
         12 . The heat-exchanger fin material according to  claim 2 , wherein the hydrophilic colored coating contains 45 to 65 parts by mass of the acrylic modified epoxy resin (A) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         13 . The heat-exchanger fin material according to  claim 2 , wherein the hydrophilic colored coating contains 2 to 13 parts by mass of the melamine resin (B) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         14 . The heat-exchanger fin material according to  claim 2 , wherein the ratio of the content of the melamine resin (B) to the content of the acrylic-modified epoxy resin (A) in the hydrophilic colored coating is 0.03 to 0.25 in terms of mass ratio. 
     
     
         15 . The heat-exchanger fin material according to  claim 2 , wherein the hydrophilic colored coating contains 30 to 50 parts by mass of the perfluoroalkyl group-containing alcohol resin (C) with respect to 100 parts by mass of resin components in the hydrophilic colored coating. 
     
     
         16 . The heat-exchanger fin material according to  claim 2 , wherein the ratio of the content of the perfluoroalkyl group-containing alcohol resin (C) to the content of the acrylic-modified epoxy resin (A) in the hydrophilic colored coating is 5/14 to 11/8 in terms of mass ratio. 
     
     
         17 . The heat-exchanger fin material according to  claim 2 , wherein the ratio of the content of the perfluoroalkyl group-containing alcohol resin (C) to the content of the melamine resin (B) in the hydrophilic colored coating is 3/1 to 10/1 in terms of mass ratio. 
     
     
         18 . The heat-exchanger fin material according to  claim 2 , wherein the hydrophilic colored coating further contains at least one of an antibacterial agent and an antifungal agent. 
     
     
         19 . The heat-exchanger fin material according to  claim 2 , wherein the coating film comprises a corrosion resistant film between the hydrophilic colored coating and the substrate, the corrosion resistant film containing at least one kind of resin selected from the group consisting of acrylic-based resins, epoxy-based resins, urethane-based resins, and ester-based resins. 
     
     
         20 . The heat-exchanger fin material according to  claim 3 , wherein the hydrophilic colored coating contains 2 to 13 parts by mass of the melamine resin (B) with respect to 100 parts by mass of resin components in the hydrophilic colored coating.