Multi-component coating method for porous substrates

Abstract

The disclosure relates to a coating method including the steps of providing a multi-component coating composition including two or more components, applying each component to a porous substrate, mixing each component with at least one other component thereby causing at least two components to undergo a chemical reaction.

1 . A method comprising:
 providing a multi-component coating composition including two or more components;   introducing each component at a rate corresponding to an application rate for each component;   applying each component to a surface of a porous substrate at the application rate;   mixing each component with at least one other component, thereby causing at least two components to undergo a chemical reaction.   
   
   
       2 . The method of  claim 1 , further comprising allowing at least some of the components to penetrate into the porous substrate. 
   
   
       3 . The method of  claim 1 , wherein the porous substrate is one of a fibrous cement substrate and a gypsum wall board. 
   
   
       4 . The method of  claim 1 , wherein the porous substrate is a fibrous cement substrate. 
   
   
       5 . The method of  claim 1 , wherein each component in the coating composition is in a separate container before the component is applied to the surface. 
   
   
       6 . The method of  claim 1 , wherein the multi-component coating composition comprises at least a first component and a second component, wherein the first component and second component comprise, respectively:
 an amino-functional compound and an oxirane-functional compound;   an amide-functional compound and an oxirane-functional compound   an amino-functional compound and an isocyanate compound;   an amino-functional compound and a (meth)acrylic functional compound;   a hydroxyl-functional compound and an isocyanate compound;   a hydroxyl-functional compound and a melamine compound;   an acid-functional compound and a melamine compound.   
   
   
       7 . The method of  claim 1 , wherein the multi-component coating composition comprises at least a first component comprising an amino-functional chemical compound, and at least a second component comprising an oxirane-functional chemical compound. 
   
   
       8 . The method of  claim 1 , wherein the multi-component coating composition further comprises at least one additive selected from the group consisting of a catalyst, a wetting agent, or a rheology control agent. 
   
   
       9 . The method of  claim 1 , wherein the multi-component coating composition comprises at least one carrier liquid. 
   
   
       10 . The method of  claim 1 , wherein the porous substrate is a fibrous cement substrate comprising a sheet having a plurality of edges adjoining a first major surface, and a second major surface adjoining the edges opposite the first major surface. 
   
   
       11 . The method of  claim 10 , wherein each component is applied to at least the first major surface and at least one of the edges. 
   
   
       12 . The method of  claim 11 , wherein each component is further applied to the second major surface and each of the edges. 
   
   
       13 . The method of  claim 1 , wherein the porous substrate is a fibrous cement substrate, and wherein a first component of the multi-component coating composition is applied to a surface of the substrate before a second component of the multi-component coating composition is applied to the surface of the substrate, and wherein a first component penetration time is allowed to elapse before applying the second component. 
   
   
       14 . The method of  claim 13 , wherein the first component comprises an amino-functional chemical compound, and wherein the second component comprises an oxirane-functional chemical compound. 
   
   
       15 . The method of  claim 1 , further comprising removing at least a portion of the multi-component coating composition from a surface of the substrate. 
   
   
       16 . The method of  claim 15 , wherein removing at least a portion of the multi-component coating composition from a surface of the substrate takes place after allowing at least some of the components to penetrate into the substrate. 
   
   
       17 . The method of  claim 15 , further comprising applying at least a portion of the multi-component coating composition removed from the surface of the substrate to a surface of a second substrate. 
   
   
       18 . The method of  claim 17 , further comprising mixing at least a portion of the multi-component coating composition removed from the surface of the substrate with at least a portion of the multi-component coating composition not previously applied to the substrate to form a recycled coating mixture before applying the recycled coating mixture to a surface of a second substrate. 
   
   
       19 . The method of  claim 15 , wherein removing at least a portion of the multi-component coating composition from the surface of the substrate comprises directing a gas stream against at least a portion of the coated surface to remove at least a portion of the multi-component coating composition. 
   
   
       20 . The method of  claim 1 , wherein applying each component to the substrate comprises coating the component onto a surface of the substrate using one or more of brush coating, knife coating, direct roll coating, reverse roll coating, spray coating, extrusion die coating, curtain coating, flood coating and vacuum coating the porous substrate is a fibrous cement substrate. 
   
   
       21 . The method of  claim 1 , wherein mixing takes place before applying each component to the substrate. 
   
   
       22 . The method of  claim 21 , wherein mixing takes place in an in-line mixer. 
   
   
       23 . The method of  claim 1 , wherein mixing occurs upon applying each component to the substrate. 
   
   
       24 . The method of  claim 1 , wherein the multi-component coating composition is applied to the substrate to obtain a dry coating weight of from about 1 g/m 2  to about 40 g/m 2 . 
   
   
       25 . The method of  claim 1 , wherein the substrate is a fibrous cement substrate, and wherein the substrate exhibits a water droplet penetration time of from about 1 second to about 15 seconds. 
   
   
       26 . A method comprising:
 providing a multi-component coating composition including at least a first component comprising an amino-functional polymer and a second component comprising an oxirane-functional polymer;   applying each component to a fibrous cement substrate;   mixing the first component with at least the second component, thereby forming a reacting mixture wherein the first and second components undergo a chemical reaction; and   allowing at least some of the reacting mixture to penetrate into the fibrous cement substrate.   
   
   
       27 . The method of  claim 26 , wherein each component is contained in a separate container prior the applying step. 
   
   
       28 . A method comprising:
 providing a multi-component coating composition comprising at least a first component comprising an amino-functional compound and a second component comprising an oxirane-functional compound, wherein each component is contained in a separate container;   applying each component to a porous substrate;   mixing the first component with at least the second component on a surface of the porous substrate, thereby forming a reacting mixture wherein the first and second components undergo a chemical reaction; and   allowing at least some of the reacting mixture to penetrate into the surface of the porous substrate.   
   
   
       29 . The method of  claim 28 , wherein the porous substrate comprises a sheet having a plurality of edge surfaces adjoining a first major surface, and a second major surface adjoining the edge surfaces opposite the first major surface, wherein each component is applied to at least the first major surface and the plurality of edges. 
   
   
       30 . The method of  claim 28 , wherein the reaction is a cross-linking reaction.