Cosmetic material containing crystalline superfine silk powder

A cosmetic material containing a colored crystalline superfine silk powder obtained by the steps of:

• bringing a silk substance into contact with an alkali aqueous solution at a temperature ranging from more than 100° C. to 150° C. and a pressure ranging from more than 1 through 5 atmospheric pressures to reduce the tensile strength of the silk substance to not greater than 0.02 g/d,
• dealkalizing and drying the silk substance,
• powdering the silk substance into a crystalline superfine silk powder below 3 μm in average particle diameter, and either
• dyeing said crystalline superfine silk powder with a natural or synthetic coloring material or mixing said crystalline superfine silk powder with a natural or synthetic coloring material.

A cosmetic material containing a crystalline superfine silk powder obtained by the steps of:

• bringing a silk substance into contact with an alkali aqueous solution at a temperature ranging from more than 100° C. to 150° C. and a pressure ranging from more than 1 through 5 atmospheric pressures to reduce the tensile strength of the silk substance to not greater than 0.02 g/d,
• dealkalizing and washing the silk substance in water,
• dyeing the silk substance with a natural or synthetic coloring material, and
• powdering the silk substance into a crystalline superfine silk powder below 3 μm in average particle diameter.

A method of preparing crystalline superfine silk powder having an average particle diameter less than 3 μm, comprising the steps of:

• contacting a silk substance with an alkali aqueous solution at a temperature of more than 100° C. and a pressure of more than one atmosphere to reduce the tensile strength of the silk substance to no greater than 0.02 g/d without dissolving the silk substance;
• dealkalizing the silk substance having the reduced tensile strength;
• drying the dealkalized silk substance;
• and
• powdering the dried silk substance to obtain crystalline superfine silk powder having an average particle diameter less than 3 μm.

A method of preparing a cosmetic material containing a colored crystalline superfine silk powder having an average particle diameter less than 3 μm, comprising the steps of:

• contacting a silk substance with an alkali aqueous solution at a temperature of from more than 100° C. to 150° C. and a pressure ranging from more than 1 through 5 atmospheres to reduce the tensile strength of the silk substance to no greater than 0.02 g/d;
• dealkalizing the silk substance having the reduced tensile strength;
• drying the dealkalized silk substance;
• powdering the dried silk substance to obtain crystalline superfine silk powder having an average particle diameter less than 3 μm;
• and either
• dyeing the crystalline superfine silk powder with a natural or synthetic coloring material or mixing the crystalline superfine silk powder with a natural or synthetic coloring material.

A method of preparing a cosmetic material containing a crystalline superfine silk powder having an average particle diameter less than 3 μm, comprising the steps of:

• contacting a silk substance with an alkali aqueous solution at a temperature of from more than 100° C. to 150° C. and a pressure ranging from more than 1 through 5 atmospheres to reduce the tensile strength of the silk substance to no greater than 0.02 g/d;
• dealkalizing and washing the silk substance in water;
• drying the silk substance;
• dyeing the silk substance with a natural or synthetic coloring material;
• and
• powdering the silk substance into a crystalline superfine silk powder having an average particle diameter than than 3 μm.

A cosmetic material containing a crystalline-superfine silk powder obtained by the steps consisting essentially of:

• bringing a silk substance into contact with an alkali aqueous solution at temperatures ranging from more than 100° C. to 150° C. and a pressure ranging from more than 1 through 5 atmospheric pressures to reduce the tensile strength of the silk substance to not greater than 0.02 g/d without dissolving the silk substance;
• dealkalizing and drying the silk substance;
• and
• powdering the silk substance into a crystalline powder below 3 μm in average particle diameter.

A method of preparing crystalline superfine silk powder having an average particle diameter less than 3 μm, consisting essentially of the steps of:

• contacting a silk substance with an alkali aqueous solution at a temperature of more than 100° C. and a pressure of more than one atmosphere to reduce the tensile strength of the silk substance to no greater than 0.02 g/d without dissolving the silk substance;
• dealkalizing the silk substance having the reduced tensile strength;
• drying the dealkalized silk substance;
• and powdering the dried silk substance to obtain crystalline superfine silk powder having an average particle diameter less than 3 μm.