Paper making shoe press belt

Abstract

A paper making shoe press belt includes a reinforcing fiber substrate and a polyurethane laminate. The reinforcing fiber substrate is embedded in at least one layer of the polyurethane laminate. At least one layer of the polyurethane laminate includes a polyurethane obtained by heat-curing a urethane prepolymer together with a mixed curing agent. The urethane prepolymer includes a terminal isocyanate group and is obtained by reacting a diisocyanate compound and a long-chain polyol. The diisocyanate compound includes at least one of toluene-diisocyanate, diphenylmethane-diisocyanate, and paraphenylene-diisocyanate. The mixed curing agent includes 70-99.5 mol % of dimethylthiotoluenediamine and 0.5-30 mol % of a curing agent. The curing agent includes at least one of diethyltoluenediamine and hydroquinone bis (β-hydroxyethyl) ether. An equivalent ratio of active hydrogen groups of the mixed curing agent to isocyanate groups of the urethane prepolymer is from 1.02 to 1.15.

1 . A paper making shoe press belt, comprising:
 a reinforcing fiber substrate; and   a polyurethane laminate;   wherein:   the reinforcing fiber substrate is embedded in at least one layer of the polyurethane laminate;   at least one layer of the polyurethane laminate comprises a polyurethane obtained by heat-curing a urethane prepolymer (A) together with a mixed curing agent (B);   the urethane prepolymer (A) comprises a terminal isocyanate group;   the urethane prepolymer (A) is obtained by reacting a diisocyanate compound (a) and a long-chain polyol (b);   the diisocyanate compound (a) comprises at least one member selected from the group consisting of toluene-diisocyanate (TDI), diphenylmethane-diisocyanate (MDI), and paraphenylene-diisocyanate (PPDI);   the mixed curing agent (B) comprises 70-99.5 mol % of dimethylthiotoluenediamine (c) and 0.5-30 mol % of a curing agent (d);   the curing agent (d) comprises at least one member selected from the group consisting of diethyltoluenediamine and hydroquinone bis (β-hydroxyethyl) ether; and   an equivalent ratio of active hydrogen groups of the mixed curing agent (B) to isocyanate groups of the urethane prepolymer (A) ((—H)/(—NCO)) is from 1.02 to 1.15.   
     
     
         2 . The paper making shoe press belt of  claim 1 , wherein the polyurethane laminate comprises an inner peripheral polyurethane layer and an outer peripheral polyurethane layer. 
     
     
         3 . The paper making shoe press belt of  claim 2 , wherein the inner peripheral polyurethane layer comprises the polyurethane obtained by heat-curing the urethane prepolymer (A) together with the mixed curing agent (B). 
     
     
         4 . The paper making shoe press belt of  claim 3 , wherein the outer peripheral polyurethane layer has a surface comprising grooves. 
     
     
         5 . The paper making shoe press belt of  claim 3 , wherein both the inner peripheral polyurethane layer and the outer peripheral polyurethane layer comprise the polyurethane obtained by heat-curing the urethane prepolymer (A) together with the mixed curing agent (B). 
     
     
         6 . The paper making shoe press belt of  claim 5 , wherein the outer peripheral polyurethane layer has a surface comprising grooves. 
     
     
         7 . The paper making shoe press belt of  claim 2 , wherein the outer peripheral polyurethane layer comprises the polyurethane obtained by heat-curing the urethane prepolymer (A) together with the mixed curing agent (B). 
     
     
         8 . The paper making shoe press belt of  claim 7 , wherein the outer peripheral polyurethane layer has a surface comprising grooves. 
     
     
         9 . The paper making shoe press belt of  claim 2 , wherein the reinforcing fiber substrate is embedded in both the inner peripheral polyurethane layer and the outer peripheral polyurethane layer. 
     
     
         10 . The paper making shoe press belt of  claim 2 , further comprising an intermediate polyurethane layer between the inner peripheral polyurethane layer and the outer peripheral polyurethane layer. 
     
     
         11 . The paper making shoe press belt of  claim 10 , wherein the reinforcing fiber substrate is embedded in the intermediate polyurethane layer. 
     
     
         12 . The paper making shoe press belt of  claim 1 , wherein the diisocyanate compound (a) comprises toluene-diisocyanate (TDI). 
     
     
         13 . The paper making shoe press belt of  claim 1 , wherein the diisocyanate compound (a) comprises diphenylmethane-diisocyanate (MDI). 
     
     
         14 . The paper making shoe press belt of  claim 1 , wherein the diisocyanate compound (a) comprises paraphenylene-diisocyanate (PPDI). 
     
     
         15 . The paper making shoe press belt of  claim 1 , wherein the curing agent (d) comprises diethyltoluenediamine. 
     
     
         16 . The paper making shoe press belt of  claim 1 , wherein the curing agent (d) comprises hydroquinone bis (β-hydroxyethyl) ether. 
     
     
         17 . The paper making shoe press belt of  claim 1 , wherein an equivalent ratio of active hydrogen groups of the mixed curing agent (B) to isocyanate groups of the urethane prepolymer (A) is from 1.05 to 1.12. 
     
     
         18 . The paper making shoe press belt of  claim 1 , wherein an equivalent ratio of active hydrogen groups of the mixed curing agent (B) to isocyanate groups of the urethane prepolymer (A) is from 1.02 to 1.10. 
     
     
         19 . The paper making shoe press belt of  claim 1 , wherein an equivalent ratio of active hydrogen groups of the mixed curing agent (B) to isocyanate groups of the urethane prepolymer (A) is from 1.10 to 1.15.