Prepreg and method of manufacturing the prepreg

Abstract

The present invention relates to a prepreg which is free from the phenomenon that air is trapped between layers to generate voids, has good handling characteristics and can produce molded articles having any complicated shape and also relates to a method of producing the prepreg. A reinforced-fiber sheet is impregnated with a matrix resin so as to form a continuous resin layer at least in the inside thereof, and then, a protective film having an irregular surface is applied to at least one surface of the reinforced-fiber sheet impregnated with the matrix resin such that the irregular surface faces the reinforced-fiber sheet. In this state, the prepreg is allowed to leave at 30 to 60° C. under the atmosphere for 12 hours or more. The resulting prepreg ( 1 ) is provided with a continuous resin layer ( 3 a ) which exists therein, wherein at least one surface of one side of the prepreg is constituted of a resin-impregnated part ( 3 b ) where the impregnated resin substantially exists and a fiber part ( 2 a ) where no resin substantially exists.

1 . A prepreg produced by impregnating a reinforced-fiber sheet with a matrix resin, wherein the prepreg comprises a continuous resin layer which exists in an inside thereof, and at least one surface of one side thereof is constituted of a resin-impregnated part where an impregnated resin substantially exists and a fiber part where an impregnated resin does not substantially exist.  
   
   
       2 . The prepreg according to  claim 1 , wherein the one surface of the one side thereof has a sea-island structure in which the fiber part constitutes a sea portion and the resin-impregnated part constitutes an island portion.  
   
   
       3 . The prepreg according to  claim 2 , wherein an area of the island portion is 1 to 80% of a total area of the one surface of the one side thereof.  
   
   
       4 . The prepreg according to  claim 1 , wherein a protective film having an irregular surface is applied to at least one surface of one side of the reinforced-fiber sheet impregnated with the matrix resin.  
   
   
       5 . The prepreg according to  claim 2 , wherein a center distance between adjacent island portions is 1 to 10 mm.  
   
   
       6 . A method of producing a prepreg, comprising: 
 impregnating a reinforced-fiber sheet with a matrix resin so as to form a continuous resin layer at least in an inside thereof; and    applying a protective film having an irregular surface to at least one surface of one side of the reinforced-fiber sheet impregnated with the matrix resin.    
   
   
       7 . The method of producing the prepreg according to  claim 6 , wherein only a convex portion of the irregular surface is brought into contact with the reinforced-fiber sheet impregnated with the matrix resin.  
   
   
       8 . The method of producing the prepreg according to  claim 6 , comprising keeping the viscosity of an impregnated resin at 10000 Poise or less for 4 hours or more in a situation where the protective film is applied to the reinforced-fiber sheet.  
   
   
       9 . The method of producing the prepreg according to  claim 6 , comprising keeping a temperature at 30 to 150° C. for 4 hours or more in a situation where the protective film is applied to the reinforced-fiber sheet.  
   
   
       10 . The method of producing the prepreg according to  claim 6 , wherein the irregular surface of the protective film is formed of a number of independent convex portions.  
   
   
       11 . The method of producing the prepreg according to  claim 10 , wherein the irregular surface of the protective film is disposed with dispersing a number of convex portions uniformly on a surface of the film.  
   
   
       12 . The method of producing the prepreg according to  claim 10 , wherein a center distance between the adjacent convex portions is 1 to 10 mm.