Method of manufacturing a randomly patterned floor covering from a preform of rubber

A method of manufacturing a predeterminately patterned floor covering having a background portion and contrastingly-colored zones arranged in a predetermined pattern on the background portion from a preform of rubber, said method comprising the steps of:

• (a) mixing a rubber mixture of a first color with contrastingly-colored particles of a second color in an amount of at least ten percent by weight so as to form an evenly mixed, random arrangement of said contrastingly colored particles of a second color in the mixture, said particles having a diameter in the range of 1.2 to 1.4 mm, being substantially free of flat surfaces, and in, at least, an advanced state of vulcanization compared to the state of vulcanization of the rubber mixture;
• (b) drawing a single-layered preform having a predetermined thickness from the rubber mixture obtained in step (a);
• (c) cutting the preform into pieces;
• (d) molding the pieces into respective blanks, each blank having a background portion having a first, average color density and a predetermined pattern of projections extending therefrom in a relief-like fashion on one side of the blank;
• (e) solidifying the blanks by vulcanization;
• and
• (f) cutting off the tops of the predeterminately patterned projections to form a predetermined pattern of zones characterized by a second average color density formed by the random arrangement of the contrastingly colored particles that contrasts with the first color density of the background portion.