Thermochromic acrylic synthetic fiber, its processed article, and process for producing thermochromic acrylic synthetic fiber

A thermochromic acrylic comprising:

• an acrylonitrile polymer having thermochrornic microcapsules dispersed therein, said thermochromic microcapsules having a non-round particle cross-section and an average particle diameter of from 0.5 μm to 30 μm;
• said thermochromic microcapsules containing a reversible thermochromic pigment composition comprising (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound and (c) a reaction medium affecting the temperature at which the color-developing reaction of the both compounds takes place;
• said thermochromic microcapsules having a hollow at a portion of their particle outer surface and having a weight ratio of reversible thermochromic pigment composition/wall film of from 7/1 to 1/1;
• said thermochromic microcapsules being contained in an amount of from 0.5% to 40% by weight based on the weight of the acrylonitrile polymer, wherein said thermochromic acrylic is formed into fibers.