Polymer compositions and products formed therewith

Abstract

The present disclosure provides compositions and products formed therefrom. In particular, the disclosure provides elastomeric latex articles, such as gloves and condoms, that can be prepared utilizing a styrene-polyisoprene-styrene (SIS) latex. The elastomeric articles can exhibit desired tensile properties while being substantially or completely free of undesired components, such as sulfur and zinc oxide, which can be allergens. The disclosure further provides methods of preparing elastomeric latex articles.

1 . An elastomeric article comprising one or more layers of a polystyrene-polyisoprene-polystyrene (SIS) latex composition, wherein the elastomeric article at a thickness of about 0.1 mm or less exhibits a tensile strength of about 20 MPa or greater when measured in accordance with ASTM D412 and exhibits a tensile modulus at 500% elongation of less than 2.75 MPa when measured in accordance with ASTM D412. 
     
     
         2 . The elastomeric article of  claim 1 , wherein the SIS latex composition is substantially free of one or more of the following: elemental sulfur or free sulfur; zinc oxide; and diphenyl guanidine. 
     
     
         3 . The elastomeric article of  claim 1 , wherein the elastomeric article exhibits an elongation at break of about 1000% or greater. 
     
     
         4 . The elastomeric article of  claim 1 , wherein the elastomeric article exhibits a tear strength of at least 2 N/mm when measured in accordance with ASTM D624-00. 
     
     
         5 . The elastomeric article of  claim 1 , wherein the elastomeric article exhibits a Young's modulus (E′) that is less than 1 MPa at a frequency of 1 Hz and that is greater than 1 MPa at a frequency of 21.5 Hz. 
     
     
         6 . The elastomeric article of  claim 1 , wherein the SIS latex composition further comprises a dithiocarbamate. 
     
     
         7 . The elastomeric article of  claim 1 , wherein the SIS latex composition further comprises a thiuram. 
     
     
         8 . The elastomeric article of  claim 1 , wherein the SIS latex composition further comprises one or more of a surfactant, an antioxidant, a viscosity modifier, a filler, and a smoothing agent. 
     
     
         9 . The elastomeric article of  claim 8 , wherein the SIS latex composition comprises a viscosity modifier including at least a hydrophobically modified alkali soluble emulsion. 
     
     
         10 . The elastomeric article of  claim 1 , wherein the elastomeric article is a condom. 
     
     
         11 . An elastomeric article formed from a composition comprising:
 polystyrene-polyisoprene-polystyrene (SIS) latex;   an amphoteric surfactant;   at least one sulfur donor; and   at least one dithiocarbamate.   
     
     
         12 . The elastomeric article of  claim 11 , wherein the composition comprises the amphoteric surfactant in an amount of 0.01 to about 2.0 phr. 
     
     
         12 . The elastomeric article of  claim 11 , wherein the composition comprises the dithiocarbamate in an amount of about 0.1 to about 2.0 phr. 
     
     
         14 . The elastomeric article of  claim 11 , wherein the composition comprises the at least one sulfur donor in an amount of about 0.1 to about 2.0 phr. 
     
     
         15 . The elastomeric article of  claim 11 , wherein the at least one sulfur donor comprises a thiuram compound. 
     
     
         16 . The elastomeric article of  claim 11 , wherein the composition further comprises one or more of an antioxidant, a viscosity modifier, a filler, and a smoothing agent. 
     
     
         17 . The elastomeric article of  claim 11 , wherein the elastomeric article at a thickness of about 0.1 mm or less exhibits a tensile strength of about 20 MPa or greater when measured in accordance with ASTM D412 and exhibits a tensile modulus at 500% elongation of less than 2.75 MPa when measured in accordance with ASTM D412. 
     
     
         18 . The elastomeric article of  claim 11 , wherein the composition is substantially free of one or more of the following: elemental sulfur or free sulfur; zinc oxide; and diphenyl guanidine 
     
     
         19 . A method for preparing an elastomeric article, the method comprising forming a film on a former using two separate formulations having different overall compositions, each of the two separate formulations comprising a polystyrene-polyisoprene-polystyrene (SIS) polymer. 
     
     
         20 . The method of  claim 19 , wherein one of the two separate formulations includes one or more cure accelerators and one or more surfactants, and wherein another of the two separate formulations expressly excludes any cure accelerators. 
     
     
         21 . The method of  claim 19 , wherein the method comprises sequential dipping of the former into separate containers that separately contain the two separate formulations to form the film on the former. 
     
     
         22 . The method of  claim 21 , wherein the method further comprises separating the sequential dipping of the former into the separate containers with a drying period that is carried out at a temperature of about 50° C. or greater for a time of about 1 minute or greater. 
     
     
         23 . The method of  claim 21 , wherein the method further comprises curing the film formed by the sequential dipping of the former into the separate containers, and the curing is carried out at a temperature of about 100° C. or greater for a time of about 5 minutes or greater. 
     
     
         24 . A method for preparing an elastomeric article, the method comprising:
 preparing a compounded latex composition include a polystyrene-polyisoprene-polystyrene (SIS) latex, at least one sulfur donor, and at least one dithiocarbamate;   prevulcanizing the compounded latex composition to form a prevulcanized compounded latex composition;   dipping a former into the prevulcanized compounded latex composition to form at least one layer of the prevulcanized compounded latex composition thereon; and   curing the at least one layer of the prevulcanized compounded latex composition on the former to provide the elastomeric article.   
     
     
         25 . The method of  claim 24 , wherein the at least one sulfur donor is a thiuram compound. 
     
     
         26 . The method of  claim 24 , wherein the at least one sulfur donor includes one or both of dipentamethylenethiuram tetrasulfide (DPTT) and dipentamethylenethiuram hexasulfide (DPTTH). 
     
     
         27 . The method of  claim 24 , wherein the compounded latex composition further includes at least one amphoteric surfactant. 
     
     
         28 . The method of  claim 24 , wherein the compounded latex composition further includes at least one antioxidant. 
     
     
         29 . The method of  claim 24 , comprising prevulcanizing the compounded latex composition in a temperature range of about 25° C. to about 40° C. for a time of about 12 hours to about 48 hours. 
     
     
         30 . The method of  claim 24 , comprising prevulcanizing the compounded latex composition until achieving a relaxed modulus of about 0.50 to about 0.61. 
     
     
         31 . An elastomeric article prepared according to the method of  claim 24 . 
     
     
         32 . The elastomeric article of  claim 31 , wherein the elastomeric article is a condom. 
     
     
         33 . The elastomeric article of  claim 31 , wherein the elastomeric article at a thickness of about 0.1 mm or less exhibits one or both of a tensile strength of about 20 MPa or greater when measured in accordance with ASTM D412 and a tensile modulus at 500% elongation of less than 2.25 MPa when measured in accordance with ASTM D412.