Abstract: Microorganism cells such as Saccharomyces or Candida yeast cells are treated with an alkaline aqueous solution with heating and stirring or with a cell wall dissolving enzyme such as glucanase or mannase to obtain cells that function as microcapsules by rapidly taking up a large amount of hydrophobic liquid. Treatment with an alkaline aqueous solution is preferably carried out at a pH of at least 8 for at least 1 hour at a temperature of 20.degree.-100.degree. C. A preferred embodiment of enzyme treatment is with .beta.-1,3-glucanase for about 30 minutes to 5 hours at pH 4-9 at a temperature of 30.degree.-60.degree. C. The treatments dissolve cell walls of the yeast such that the walls still have sufficient strength for enclosing hydrophobic liquids.

Abstract: There is disclosed a heat sensitive recording material comprising a color-forming agent consisting of an aromatic isocyanate compound and an imino compound, and a phenol compound; said recoridng material being excellent in storability of image and storability of non-image area as well.

Abstract: The present invention provides a heat sensitive recording material which is less in fog in background area and has superior color toning effect with high image storage stability which contain a fluoran compound represented by the following formula in addition to an aromatic isocyanate compound and an imino compound having at least one >C.dbd.NH group which forms color upon application of heat: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 each represents a hydrogen atom, a lower alkyl group, a cyclohexyl group or an allyl group and R.sub.4 and R.sub.5 each represents a hydrogen atom, a lower alkyl group, a phenyl group, a cyclohexyl group or an aralkyl group. This heat sensitive recording material may further contain a heat fusible substance and/or a phenol compound to further improve heat responsivity or anti-fogging properties of background portion.