Production apparatus of multilayer coating film

Abstract

A method for forming multiple coating layers produces a coating construction that has flexibility corresponding to the number of layers of multiple coating layers, by which a multilayer coating film can be produced with small film thickness without adherence of dust to a film surface, a drying fault such as unevenness induced by drying-wind on the film surface, or a coating fault such as a level variation and a streak. The multilayer coating film has a coating surface state of high quality with coating thickness deviation of 3% or less. In the method, a belt-like substrate is continuously fed. A coating/drying step follows, with multiple steps performed in a single unit. A plurality of coating layers are formed by sequentially performing the coating/drying step by multiple units. Finally, the belt-like substrate with the multiple coatings is continuously wound.

1 . A method for forming a multiple coating layers, comprising: 
 continuously feeding a belt-like substrate;    performing a coating/drying step in which following steps (i) to (iv) are performed in a single unit; 
 (i) introducing the belt-like substrate into a casing and continuously transferring the belt-like substrate to a coating zone;  
 (ii) forming a single coating layer by applying a coating solution onto the belt-like substrate while performing the continuous transferring;  
 (iii) drying the single coating layer while performing the continuous transferring; and  
 (iv) leading the belt-like substrate out of the casing;  
   forming a plurality of coating layers by sequentially performing the step of coating/drying by a plurality of units, each of which is the single unit, arranged a number of times being equal to a number of the plurality of coating layers; and    continuously winding the belt-like substrate on which the multiple coating layers are formed.    
   
   
       2 . The method for forming a multiple coating layers according to  claim 1 , further comprising: 
 forming a down flow of clean air by exhausting a clean air blown from an air inlet port formed at a ceiling surface of the casing through an exhausting port formed at a bottom surface of the casing.    
   
   
       3 . The method for forming a multiple coating layers according to  claim 2 , wherein in transferring the belt-like substrate in at least one of the steps of (i) introducing, (ii) forming, and (iv) leading, 
 the belt-like substrate is transferred in a box-shaped or tube-shaped transfer path case provided in the casing along the transfer path, and    a part of clean air, which is blown from the air inlet port at a ceiling surface, is introduced from an air introduction port formed at inlet port side of the transfer path case and the part of clean air is exhausted through an air exhaust port formed at exhaust side of the transfer path case.    
   
   
       4 . The method for forming a multiple coating layers according to  claim 3 , wherein an inside pressure of the transfer path case is kept higher than an outside pressure.  
   
   
       5 . The method for forming a multiple coating layers according to  claim 3 , wherein 
 a plurality of pass rollers are placed in the transfer path case along the transfer path, and    only a roller shell portion of the plurality of pass rollers is enclosed by the transfer path case.    
   
   
       6 . The method for forming a multiple coating layers according to  claim 4 , wherein 
 a plurality of pass rollers are placed in the transfer path case along the transfer path, and    only a roller shell portion of the plurality of pass rollers is enclosed by the transfer path case.