Production method for organopolysiloxane emulsion composition

A method for producing an organopolysiloxane oil-in-water emulsion composition, the method comprising the steps of:

• (I) preparing an emulsion composition by emulsifying a mixture comprising
• (A) 100 parts by weight of an organopolysiloxane of general formula (1) below which has an octamethylcyclotetrasiloxane content of not more than 1,000 ppm
• HO(R12SiO)nH (1)
• (wherein each R1 is independently a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group of 1 to 20 carbon atoms, and n is a number such that the organopolysiloxane has a viscosity at 25° C. of at least 200 mm2/s and less than 2,000 mm2/s),
• (B) from 1 to 8 parts by weight of a surfactant of general formula (2) below having an alkylnaphthalene skeleton
• R2a—C10H(7-a)—SO3M (2)
• (wherein R2 is a linear or branched alkyl group of 1 to 30 carbon atoms;
• M is a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an ammonium ion or a tertiary ammonium ion;
• and a is an integer from 1 or 3), and
• (C-1) from 1 to 10,000 parts by weight of water;
• and
• (II) after optionally adding to the resulting emulsion composition
• (C-2) from 0 to 10,000 parts by weight of water, carrying out emulsion polymerization at a temperature below 40° C. in the presence of
• (D) an acid catalyst, which is optional when component (B) is catalytic,
• wherein the organopolysiloxane that forms has a viscosity at 25° C. of at least 300,000 mPa·s, the amount of octamethylcyclotetrasiloxane included in the organopolysiloxane that forms is not more than 3,000 ppm, and the size of the resulting emulsion particles is not more than 500 nm,
• wherein the organopolysiloxane emulsion composition that forms after Step (II) is stable at 50° C. for at least 3 months.