Elastic laminates and process for producing same

Abstract

A method is provided for producing elastic composite laminates. The laminates contain elastic filaments that are stretched and laminated to at least one facing material. The continuous filaments are laminated to the facing material using a starved slot coat process. The starved slot coat process provides various benefits and advantages including the production of laminates having improved properties.

1 . A method for producing a composite material comprising: 
 extruding continuous filaments, the filaments comprising an elastomeric material;    stretching the continuous filaments;    applying an adhesive material to a first side of a facing material, the adhesive material being applied to the facing material from a slot extrusion die, the adhesive material forming a discontinuous coating comprising amorphous elements of the adhesive material; and    laminating the stretched continuous filaments to the first side of the facing material after the adhesive material has been applied.    
   
   
       2 . A method as defined in  claim 1 , wherein, in terms of basis weight per area, the adhesive material is applied in a substantially uniform manner over the first side of the facing material.  
   
   
       3 . A method as defined in  claim 1 , further comprising the step of applying an adhesive material to a first side of a second facing material, the adhesive material being applied to the second facing material from a slot extruder; and 
 laminating the stretched continuous filaments to the first side of the second facing material, the stretched continuous filaments being positioned in between the first facing material and the second facing material to form the composite material, the composite material having a porosity of less than about 300 cfm per ft 2 .    
   
   
       4 . A method as defined in  claim 3 , wherein the first facing material and the second facing material comprise spunbond webs.  
   
   
       5 . A method as defined in  claim 1 , wherein the slot extrusion die defines a slot through which the adhesive material is emitted, and wherein the first side of the facing material contacts the slot as the adhesive material is applied to the facing material.  
   
   
       6 . A method as defined in  claim 1 , wherein the adhesive material is applied to the first side of the facing material in an amount less than about 4.4 gsm.  
   
   
       7 . A method as defined in  claim 1 , wherein the adhesive material is applied to the first side of the facing material in an amount from about 0.5 gsm to about 3 gsm.  
   
   
       8 . A method as defined in  claim 1 , wherein the adhesive material comprises a styrenic block copolymer, a random copolymer of a polyolefin, an amorphous polyalphaolefin, or mixtures therof.  
   
   
       9 . A method as defined in  claim 1 , wherein the adhesive material comprises a hotmelt adhesive.  
   
   
       10 . A method as defined in  claim 1 , wherein the adhesive material has a viscosity of from about 500 cp to about 50,000 cp as the material is being applied to the first side of the facing material.  
   
   
       11 . A method as defined in  claim 1 , wherein the continuous filaments move vertically downward as they are formed and laminated to the first facing material.  
   
   
       12 . A method as defined in  claim 1 , further comprising the step of relaxing the composite nonwoven material after the continuous filaments are laminated to the facing material.  
   
   
       13 . A method as defined in  claim 1 , further comprising the step of applying an adhesive material to a first side of a second facing material, the adhesive material being applied to the second facing material from a slot extrusion die, the adhesive material forming a discontinuous coating comprising amorphous elements of the adhesive material; and 
 laminating the stretched continuous filaments to the first side of the second facing material after the adhesive material has been applied to the second facing material, the stretched continuous filaments being positioned in between the first facing material and the second facing material to form the composite nonwoven material.    
   
   
       14 . A method as defined in  claim 1 , wherein the continuous filaments are stretched by being conveyed over at least one roller.  
   
   
       15 . A method as defined in  claim 1 , wherein the facing material comprises a nonwoven web having a basis weight of from about 0.2 osy to about 1.5 osy.  
   
   
       16 . A method as defined in  claim 15 , wherein the nonwoven web comprises a spunbond web.  
   
   
       17 . A method as defined in  claim 1 , wherein the elastomeric material used to make the filaments comprises an elastomer selected from the group consisting of elastic polyesters, elastic polyurethanes, elastic polyamides, elastic copolymers of ethylene and at least one vinyl monomer, elastic metallocene-catalyzed polyolefins, and elastic block copolymers.  
   
   
       18 . A method as defined in  claim 1 , wherein the resulting composite material has at least three layers and has an air permeability of less than about 350 cfm per ft 2 .  
   
   
       19 . A method as defined in  claim 1 , wherein the resulting composite material comprises only two layers including the layer of continuous filaments in the facing material, the facing material comprising a spunbond web, the composite material having an air permeability of less than about 400 cfm per ft 2 .  
   
   
       20 . A composite elastic material comprising: 
 elastic continuous filaments extending generally in the same direction, the continuous filaments comprising an elastomeric material;    a nonwoven web having a first side and a second side, the first side of the nonwoven web being laminated to the elastic continuous filaments, the elastic continuous filaments being laminated to the nonwoven web in a stretched state such that the nonwoven web gathers when the elastic continuous filaments are relaxed; and    an adhesive material bonding the elastic continuous filaments to the first side of the nonwoven web, the adhesive material comprising a discontinuous coating on the first side of the nonwoven web, the discontinuous coating comprising amorphous elements of the adhesive material, the adhesive material being present on the nonwoven web in an amount less than about 4.4 gsm.    
   
   
       21 . A composite elastic material as defined in  claim 20 , wherein the adhesive material is present on the first side of the nonwoven web in an amount from about 0.8 gsm to about 3 gsm.  
   
   
       22 . A composite elastic material as defined in  claim 20 , wherein the adhesive material comprises a styrenic block copolymer, a random copolymer of a polyolefin, an amorphous polyalphaolefin, or mixtures therof.  
   
   
       23 . A composite elastic material as defined in  claim 20 , wherein the adhesive material comprises a hotmelt adhesive.  
   
   
       24 . A composite elastic material as defined in  claim 20 , further comprising a second nonwoven web having a first side and a second side, the first side of the second nonwoven web being laminated to the elastic continuous filaments such that the elastic continuous filaments are positioned in between the first nonwoven web and the second nonwoven web; and 
 an adhesive material bonding the elastic continuous filaments to the first side of the second nonwoven web, the adhesive material comprising a discontinuous coating on the first side of the second nonwoven web, the discontinuous coating comprising amorphous elements of the adhesive material, the adhesive material being present on the first side of the second nonwoven web in an amount of less than about 4.4 gsm.    
   
   
       25 . A composite elastic material as defined in  claim 20 , wherein the nonwoven web comprises a spunbond web having a basis weight of from about 10 gsm to about 20 gsm.  
   
   
       26 . A composite elastic material as defined in  claim 20 , wherein the elastomeric material used to form the continuous filaments comprises an elastomer selected from the group consisting of elastic polyesters, elastic polyurethanes, elastic polyamides, elastic copolymers of ethylene and at least one vinyl monomer, elastic metallocene-catalyzed polyolefins, and elastic block copolymers.  
   
   
       27 . A composite elastic material as defined in  claim 24 , wherein the composite elastic material has an air permeability of less than about 350 cfm per ft 2 .  
   
   
       28 . A composite elastic material as defined in  claim 20 , wherein the adhesive material is present on the first side of the nonwoven web in a substantially uniform manner in terms of amount per unit area.  
   
   
       29 . A composite elastic material as defined in  claim 20 , wherein the composite elastic material only comprises two layers including a layer of the continuous filaments and the nonwoven web, the nonwoven comprising a spunbond web, the composite elastic material having an air permeability of less than about 400 cfm per ft 2 .  
   
   
       30 . A composite elastic material as defined in  claim 20 , wherein the adhesive only coats the surface fibers of the nonwoven web and does not appreciably deposit in any pores on the nonwoven web.