4. Emill

An optimum soaping agent for reactive dyestuff will require:

• Insusceptibility to water quality and hardness
• Soaping properties with minimal fluctuation due to temperature, capable of producing sufficient effects even in low temperatures
• High affinity to dyestuff, properties of forming additional chemical compounds with hydrolyzed dyestuff component but without affinity to fiber
• Causing no color alteration after soaping
• Properties of promoting diffusion, dispersion, solubility of washed-off dyestuff and further washing off supported by appropriate water temperature, mechanical movement of cloth, flow rate, agitation and frequency of squeezing and rinsing

• Quick, powerful soaping
• A great soaping result even in a small bath ratio
• Prevention of color redeposition from wash-off
• Reduction in the frequency of rinsing (easy rinsing)
• Low foam (no foam)
  

Group (A)

G-170, G-100 and G-50 potently prevent redeposition of wash-off and staining besides removing it. White-ground soaping agents suitable for prints. Versatile and inexpensive.

Group (B)

2G conc, 2G conc new and BZ conc are conc-type products with superior soaping properties and good stain removal.

Group (C)

R-60, YK and 2G can balance the performance between wash-off removal and prevention of staining (the characteristics of A and D). Most conventional, versatile and inexpensive products.

Group (D)

Powerful soaping with anti-staining/redeposition properties, outstanding effects in the removal of staining 5G conc., SK-D: Also suitable for deep-printing G-A: Good for deep-dyeing (black)

Table 1 is the summary of the performances, purposes and characteristics of above products. Table 1 Emill group characteristic, performance and method

Table1 EMILL: each group's characteristic, performance and method

The following are specific data on practical use.

When dyeing only the cotton side of polyester/cotton union cloth (border pattern) with reactive black dyestuff (VS type), the polyester side becomes stained and is no longer available for reserve dyeing. The graph in Fig.2 shows that the amount of reactive dyestuff remaining on the polyester part and the amount of unfixed dyestuff on the cotton after soaping this one-side dyed material at 60°C, 75°C and 90°C.

Fig.2 Staining on polyester/cotton union cloth after one-side reactive dyeing and soaping

In ②, the high-temp (90°C) rinsing removed more than 50% of unfixed dyestuff on the cotton part without using any soaping agent, but it proved impossible to remove the stain on the polyester.

In ③ and ④, a competitor's soaping agent was added. Removal of stains on polyester was incomplete, without any improvement observed even with the use of STPP (sodium tripolyphosphate).

In ⑤ and ⑥, EMILL SK-D was used. Deposition on both fibers was removed effectively with soaping above 75°C. The addition of STPP proved effective and brought about improved results.

Fig.3 shows comparison of anti-staining effects and colorfastness to washing according to the kind of soaping agent in 60°C, 75°C and 90°C soaping of reactive-dyed cotton.

Fig.3 Comparison of anti-staining effects and washing fastness after the soaping of reactive-dyed cotton

Soaping was carried out directly after dyeing 100% cotton knit with C. I. Reactive Red 120, without undergoing cold or hot rinsing. To test the anti-staining of white ground, stains on white cloth were observed with a white cloth added to the soaping bath. To test fastness to washing, bleeding on an attached white cloth was measured after the soaping and drying of a dyed cloth, using the launderometer, based on JIS A-4 method.

② is a conventional type with a balance between removing and anti-staining properties.

③ causes no staining on white ground because of low removing properties and has very low fastness to washing.

④ is potent in removal but inferior in preventing staining, resulting in more redeposition of dyestuff and low washing fastness.

As described above, the performance of soaping agents differ according to the kind. Emill G-170 (⑤) has a very low concentration of 0.5 g/L and shows great results in both anti-staining of white ground and washing fastness.

Fastness examination of dyed, soaped cloth (dyestuff bleeding test)

Competitor's 2 g/L	Emill 5G conc 1 g/L

Test method

Dyeing of cotton cloth with CI Reactive Black 5 →Soaping (80°C x 10min) and drying →The dyed cloth and cotton white cloth sewn together vertically →The bottom of the dyed cloth dipped in a 0.5g/L solution of nonionic surfactant, 20°C x 10min. →Determination of the bleeding rate of the reactive dye remaining unfixed on the white cloth