With the continuous progress and development of textile dye post-processing technology, and the formal promulgation of the EU REACH regulation, the selection of dyes and additives with excellent performance and environmental protection requirements is more and more valued by the textile industry. At the same time, textile dyes and additives are selected Safe and effective dispersants will become particularly urgent. Among the types of dispersants, lignosulfonates are the most effective. The raw materials of dispersants such as Medline's sodium lignin sulfonate sodium salt are natural pine wood, which has excellent dispersion stability for hydrophobic substances. It has gradually replaced or blended traditional naphthalene sulfonate dispersants in many industries. Used for processing products in textile dyes, pesticides, construction and other industries.

Lignin sulfonate is an anionic surfactant. It is a natural polymer containing a large number of carboxyl groups, methoxy groups, and sulfonic acid groups. The average molecular weight of different products is distributed in the range of 5 000 to 21,000. The sulfonate is generally the sodium salt. , Calcium salt, and also ammonium salt, is a polymer electrolyte. Due to the difference in the average molecular weight and the degree of sulfonation of wood turbulent dispersant, its end use is also very different. For example, Bordeperse AM-320, a lignin sulfonate ammonium salt of Medveg Weike, is more effective than other sulfonates in improving the solubility of acid dyes in cold water. It is widely used in the post-processing of metal complex acid dyes and weak acid dyes In the process, it is used to produce high-quality acid printing dyes. The high-purity lignin sulfonate ammonium salt has not yet been produced in China. U1trazine NA of Medvec Vic Co. has high purity and extremely low color sodium lignosulfonate, which is widely used in the post-processing of reactive dyes and acid dyes, which can significantly improve the cold water solubility of reactive dyes and acid dyes and reduce The generation of color points on the surface of dye printing cloth. And without any negative impact on the viscosity of printing paste, it is widely used to produce high-quality reactive and acid printing dyes. In the textile auxiliaries industry, Ultrizine NA is also used as a reactive dye dyeing and dispersing leveling agent, used to improve the level dyeing of reactive dyes such as reactive turquoise and other easily dyed flowers, and is especially suitable for cotton and polyester cotton package yarn dyeing. Adding Uhrazine NA during continuous dyeing with vat dyes can also prevent the occurrence of stains on the cloth. REX 85A is a multi-purpose dyeing and dispersing agent in the textile auxiliary industry. It is used to disperse dyes on polyester and acetate fibers. It can effectively prevent the dye from agglomerating under high temperature dyeing conditions and improve the leveling performance. It is especially suitable for low-bath ratio dyeing conditions such as package dyeing machine, roll dyeing machine, overflow dyeing machine, etc. Kraftsperse 1251 is a high-purity mixed lignin dispersant with very low staining on multi-fibers, which can effectively reduce the viscosity of the additive system. It is widely used in pigments and dye inkjet printing inks And, it is very effective to increase the carbon black addition amount and storage dispersion stability of carbon ink.

Determination of formaldehyde content in textile additives

    As China joins wro, foreign countries have put forward higher requirements on the ecology of textiles, and the control of harmful substances in textiles will be more stringent. The amount of formaldehyde in textiles is an indicator that is required to be tested more frequently. GB 18401-2003 (national The Basic Safety Technical Code for Textile Products and Oeko-Tex Standard 100-2004 General and special conditions strictly stipulate the limit value of free formaldehyde contained in different textiles + which stipulates that the amount of free formaldehyde in infants and young children is not detectable; direct contact with skin ≤75x 10; Indirect skin contact ≤300x 10. The textile auxiliary is the main source of residual formaldehyde in textiles, and the amount of formaldehyde is directly related to the residual amount on textiles.

1. Comparison of related methods

At present, there is no systematic method for determining the amount of formaldehyde in textile auxiliaries. By comparison, GB 18582-2001 "Interior Decoration and Decoration Materials Inner Wall Paint Limitation of Harmful Substances" Appendix B, GB 18583-2001 "Interior Decoration Materials Adhesives" Appendix A, GB 5543-1985 (Determination of Total Formaldehyde in Resin Finishing Agents), Appendix A, GB 5543-1985, Determination of Formaldehyde in 3 National Standards, combined with GB / T 2912.1-1998 "Determination of Formaldehyde in Textiles Part 1: Free Hydrolyzed formaldehyde (water extraction method) "(see Table 1), and then according to the characteristics of the additives, the following detection methods are proposed. As can be seen from Table 1, (1) ① ② ③ are used to extract formaldehyde by distillation, ④ by extraction Method for extracting formaldehyde; (2) ①②④ is to develop the color of the fraction with acetylacetone, and then use a spectrophotometer to determine the amount of formaldehyde in the color developing solution, ③determine the amount of formaldehyde in the fraction by iodometric method. Compared with ①②④, ③ If the distillate contains reducing or oxidizing substances, it will affect the measurement results; (3) Textile additives are used on textiles, and the method for determining the formaldehyde of textiles is based on GB / T 2912.1-1998. ①②④ The standard curve is produced in different ways. Considering the continuity of the determination method of formaldehyde in textiles and textiles, it is appropriate to use ④ for the preparation of the standard curve; (4) In the actual operation process, if the amount of formaldehyde in the sample is too low (<20> 1 ooo mg / kg), after the fraction is colored by acetylacetone, some crystals will be generated, causing spectrophotometric colorimetric measurement error. Therefore, the following detection method is only applicable to textiles with 20-500 mg / kg formaldehyde Additives.

Second, the detection method

A. Principle

After taking a certain amount of sample and distilling the fraction obtained by 100 oC distillation at a certain ratio with tertiary water, in the acetate-ammonium acetate buffer solution, formaldehyde in the fraction reacts with acetylacetone to form a stable yellow compound at 412 am Measure the absorbance at the wavelength and calculate the amount of formaldehyde in the sample according to the standard curve

B. Reagents and instruments

Reagents: ammonium acetate, glacial acetic acid, formaldehyde, phosphoric acid, acetylacetone, all of which are analytically pure, and the water meets the requirements of tertiary water in GB / T 6682. Instrument: analytical balance, with straight condenser tube full glass distillation device Oil bath, spectrophotometer.

C. Prepare solution

1. Acetylacetone solution

Weigh 150g of ammonium acetate, dissolve it with 800mL of water, then transfer to a 1000mL volumetric flask, then add 3mL of glacial acetic acid and 2mL of acetylacetone, dilute with water to the mark, and store in a brown bottle.

2. Formaldehyde stock solution

Take 3.8 mL formaldehyde into a 1 000 mL volumetric flask and dilute to the mark with water. The mass concentration of the formaldehyde stock solution is about 1 500 Ixg / mL: the calibration of the formaldehyde stock solution E is carried out according to the provisions of Appendix A of GB / T 2912.1-1998

3. Formaldehyde standard solution

Transfer 100 mL of the calibrated formaldehyde stock solution to a 1,000 mL volumetric flask and dilute to the mark with water.

D. Standard curve drawing

According to the volume of formaldehyde standard solution listed in Table 2, add 6 100 mL volumetric flasks respectively, dilute to the mark with water, mix well, and transfer 5.00 mL to 25 mL colorimetric tube with stopper by pipette, add 5.00 each mL acetylacetone solution, shake well, place in (4o ~ 2Fc water bath (3O ± 5) rain to develop color, take out and cool to room temperature, use a 1 cm absorption cell, use the blank solution as a reference, at a wavelength of 412 am Measure the absorbance at the place, the blank solution is (5.00 mL water + 5000 mL acetylacetone solution).