Roll film, method for producing roll film, method for producing copper-clad laminate and method for producing printed board

Abstract

A roll film comprising a melt-processable fluororesin as the main component and having a thickness of from 1 to 100 μm, the dimensional change rate of which is less than 1.0%, in terms of an absolute value, in each of MD and TD, when heated at 150° C. for 30 minutes and then cooled to 25° C., based on the dimension at 25° C.

What is claimed is: 
     
         1 . A roll film comprising a melt-processable fluororesin as the main component and having a thickness of from 1 to 100 μm, the dimensional change rate of which is less than 1.0%, in terms of an absolute value, in each of MD and TD, when heated at 150° C. for 30 minutes and then cooled to 25° C., based on the dimension at 25° C. 
     
     
         2 . The roll film according to  claim 1 , wherein the ratio of the tension when wound to the dimensional change rate, in terms of an absolute value, in MD is from 100 to 1,000,000. 
     
     
         3 . The roll film according to  claim 1 , which is used for a copper-clad laminate. 
     
     
         4 . The roll film according to  claim 1 , wherein the melt-processable fluororesin is a fluororesin having units derived from tetrafluoroethylene and units derived from a perfluoro(alkyl vinyl ether). 
     
     
         5 . The roll film according to  claim 1 , wherein the melt-processable fluororesin is a fluororesin having a functional group having an ion scavenging function. 
     
     
         6 . The roll film according to  claim 1 , which comprises a melt-processable fluororesin having a functional group having an ion scavenging function and a melt-processable fluororesin other than the above hot-melt fluororesin as the main component. 
     
     
         7 . The roll film according to  claim 1 , which has a layer of the melt-processable fluororesin and a layer of a melt-processable fluororesin having a functional group having an ion scavenging function. 
     
     
         8 . The roll film according to  claim 5 , wherein the functional group having an ion scavenging function is at least one member selected from the group consisting of a carbonyl group, a carboxy group, a carboxylic acid anhydride group (—C(═O)—O—C(═O)—), a carboxylate group, a sulfonyl group, a sulfo group and a sulfonic acid anhydride group (—S(═O) 2 —O—S(═O) 2 —). 
     
     
         9 . The roll film according to  claim 1 , which has a thickness of from 3 to 75 μm. 
     
     
         10 . A method for producing the roll film as defined in  claim 1 , which comprises subjecting a film comprising the melt-processable fluororesin as the main component and having a thickness of from 1 to 100 μm to annealing treatment at from a temperature lower by 210° C. than the melting temperature (Tm) of the melt-processable fluororesin to a temperature lower by 20° C. than Tm and then winding the film. 
     
     
         11 . The method according to  claim 10 , wherein the annealing treatment is carried out with a tension of at most 10 N/m applied to the film. 
     
     
         12 . The method according to  claim 10 , wherein the film is wound with a tension of at most 500 N/m applied on the film. 
     
     
         13 . A method for producing a copper-clad laminate, which comprises unwinding the roll film as defined in any one of  claim 1  and forming a copper layer on a surface of the unwound film. 
     
     
         14 . The method according to  claim 13 , which forms a copper layer having an AC resistance value of higher than 1.0×10 −9  Ω·cm. 
     
     
         15 . A method for producing a printed board, which comprises producing a copper-clad laminate by the method as defined in  claim 13  and etching the copper layer to form a patterned circuit.