Post-finishing: Reasonable selection of finishing agents
The finishing and functional finishing of fabrics are mostly carried out in the later stages of dyeing and finishing. The auxiliaries remain more on the fabric, and the chemical substances in the finishing auxiliaries are more likely to reach 1 tpy (tons/year/per manufacturer or importer) According to the registration requirements, if the finishing agent contains SVHC (chemical substances of very high concern), its concentration in the fabric can easily reach 0.1%. In order to prevent the content of chemical substances on textiles from exceeding the requirements, corresponding alternative finishing technologies should be actively developed. Choose finishing agents rationally, avoid SVHC and restricted chemicals, or try to keep the SVHC chemical content on the fabric below 0.1%.
Anti-wrinkle finishing
Formaldehyde is a restricted substance in the REACH regulations, and its restricted content is still implemented in accordance with 76/769/EEC. How to overcome the formaldehyde content in textiles The problem is still one of the directions for dyeing and finishing technology efforts. Traditional anti-wrinkle press finishing agents include 2D resin (dimethylol dihydroxy cycloethylene urea resin, DMDHEU), trimethylol melamine resin (TMM) and hexamethylol melamine resin (HMM). These resins are used in It is easy to cause hydrolysis of cross-linked bonds during use and storage, releasing formaldehyde, and its resin finishing agent contains free formaldehyde.
In order to meet the EU’s relevant textile formaldehyde content requirements, three finishing processes can be used: etherification low-formaldehyde and ultra-low formaldehyde finishing (such as Huntsman’s Knittex RCT low-formaldehyde dry cross-linked resin, Knittex FA conc. Low-formaldehyde wet cross-linking resin, Clariant’s Arkofix MCL low-formaldehyde resin, BASF’s Fixpret ECO low-formaldehyde resin, Huntsman Knittex FEL ultra-low formaldehyde resin, etc.), polyurethane resin finishing (such as Lanxess’s Baypret USV polyurethane Finishing agent, used with reactive resin to reduce free formaldehyde content) and formaldehyde-free resin finishing (such as Clariant’s Arkofix NEFliq’s BTCA formaldehyde-free resin finishing agent, etc.). It is worth noting that formaldehyde-free finishing agents are currently unable to completely replace N-hydroxymethyl resin finishing agents, and their anti-wrinkle effect, strength reduction and cost need to be further developed.
Softening finishing
The current prominent issue in softening finishing in response to REACH regulations is the content control of APEO. The EU requires that the APEO content in textiles should be less than 0.1 % (1000mg/kg), but there are an increasing number of large EU buyers who require APEO-free textiles, such as A&M and other companies. The softeners used in the softening and finishing of textiles are divided into four types according to their ionic properties: cationic, nonionic, anionic and amphoteric. Cationic softeners are widely used, including amino silicone oil (and polyether silicone oil, epoxy silicone oil, methyl silicone oil, hydrogenated silicone oil, hydroxyl silicone oil) softeners that are used in large quantities in my country. APEO is generally used as this type of softener. The dosage of emulsifier is 30% to 50% of amino silicone oil. It is difficult for various silicone oil emulsions composed of APEO to meet the requirements of REACH. New APEO-free softeners should be used as much as possible, such as Clariant’s Sandoperm SEI oil liq softener and Swiss Brookline company’s Brooksil Ml6 softener.
Nonionic softeners rank second in usage in my country, among which fatty acid amide softeners are used more frequently, which can react with cellulose fibers to give fabrics a durable softening effect, such as softeners MS-80, softener HRQ and softener TR. This type of softener releases formaldehyde during use and storage and has biodegradation and toxicity issues, so its use should be avoided.
Anionic softeners are mainly silicone resin type and succinate type, amphoteric softeners mainly include fatty amine and acrylate condensate and stearic acid type, etc. The dosage of these two types of softeners There are fewer species and varieties, and toxicity and biodegradability are their main problems. Currently, products that can meet ecological requirements include BASF’s Pesistol KF (amphiphilic type) and Japanese Daiei Chemical Co., Ltd.’s softener AS-350 (anionic type).
Waterproof and oil-proof finishing
At present, my country’s annual import of organic fluorine finishing agent raw materials has reached 11,000 tons in recent years. my country’s waterproof and oil-proof finishing and “three Fluorine-containing finishing agents are mostly used for anti-”finishing, which leads to the problem that the finished products contain PFOS (perfluorooctanoate) and PFOA (perfluorooctanoic acid). PFOS is currently a refractory organic pollutant. The European Union has banned the sale of finished products with a mass fraction of PFOS exceeding 0.005% (50 mg/kg) on the market. Although PFOA has not yet been banned by the EU, it has been banned by several well-known textile brand companies such as H&M. PFOS-free and PFOA-free finishing is the inevitable direction for waterproof, oil-proof and “three-proof” finishing in the future.
Therefore, when carrying out waterproof, oil-proof and “three-proof” finishing, finishing agents must be correctly selected. There are currently three types of finishing agents available for selection. One is acrylic fluorocarbon ester finishing agents, such as Huntsman’s Oleophobol C, 3M’s Scout Guard FC, Asahi Glass’s Asahiguard AG, Japan’s Daikin’s Unidyne TG, DuPont’s Zepel, etc.; the second is fluorine-containing stain-removing finishing agents containing hydrophilic segments, such as Unidyne TG-991 from Japan’s Daikin Company; the third is modified silicone polyemulsion finishing agents, such as Finish WS 60E from Wacker Company in Germany. wait. AA
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