Dimethyl-5-Sulfoisophathalate Sodium salt (DMSIP, CAS:3965-55-7) is mainly used to produce the dyed polyester chip.DMSIP(CAS:3965-55-7)is also used in water dispersible resin systems applied in coating and adhesives.DMSIP(CAS:3965-55-7) is acting as the third monomer of cation modified polyester(CDPET).DMSIP(CAS:3965-55-7) has a good affinity function with cation dyestuff because of the CDPET fiber containing sulfo group,the dyed fiber is bright and lustrous,having a complete range of color and dying deeply.The modified fiber has woolens feeling,it is easily blended with fleece that is necessary for garments manufacturing.