Environmental urea-free pretreatment process to form new surface on hemp for enhancing the inkjet printing performance

Because of the non-cellulose substance in hemp fabric, such as pectin and waxiness, the inkjet printing products have light color yield and poor color fastness. Moreover, the inkjet printing pretreatment solution generally included urea, which might pollute the environment. Thus, an environmentally friendly pretreatment process was used in this study for improving hemp inkjet printing, which only included carboxymethyl guar gum (CMG) and NaHCO3. The results shown that the hemp fabrics pretreated with CMG had a longer wetting time and bigger contact angle. The pores of the freeze-dried CMG were far more than the sodium alginate. CMG pretreated fabric could absorb more dyes, which reacted with fibers. The results demonstrated that the K/S values of inkjet-printed hemp fabric reached the maximum when the pretreatment solution was 1.5 % CMG and 2 % NaHCO3. Compared with sodium alginate, the K/S values of the cyan, magenta, yellow and black color blocks of CMG pretreated hemp fabric increased by 36 %, 10 %, 26 % and 63 % respectively. Thus, the free-urea pretreatment process cannot only improve the inkjet printing performance and reduce the discharge of industrial wastewater, but also save raw materials and promote the development of the textile industry.