Applicator die

A die for alternately depositing first and second liquid materials on the surface of a moving web to form a coating layer thereon, said die comprising

• a die body defining an elongated coating orifice, first and second liquid passageways communicating with said coating orifice, first and second inlet orifices communicating with said first and second liquid passageways, respectively, and closure means for alternately opening and closing said first and second liquid passageways, said closure means being adapted to:
• (a) define a closed passage from said first inlet orifice to said coating orifice when said second liquid passageway is closed, whereby said first liquid material can flow from said first inlet orifice through said coating orifice but is prevented from entering said second liquid passageway, and said second liquid material is prevented from flowing through said coating orifice or entering said first liquid passageway;
• and
• (b) define a closed passage from said second inlet orifice to said coating orifice when said first liquid passageway is closed, whereby said second liquid material can flow from said second inlet orifice through said coating orifice but is prevented from entering said first liquid passageway, and said first liquid material is prevented from flowing through said coating orifice or entering said second liquid passageway;
• whereby the supply of liquid to said coating orifice is switched rapidly and positively from said first liquid material to said second liquid material and from said second liquid material to said first liquid material, and leakage of said first liquid material and second liquid material into one another is prevented.