Water-based PU coating technology for textiles

Number

422-EN

Section

General Section

Use

Sector

Manufacture of textiles, leather, fur

Function

Other

Process

Other

Product category

Textile dyes, and impregnating poducts

Abstract

Coated textiles find use in industries as diverse as automotive, sportswear and fashion apparel & footwear, as well as myriad technical applications. Covestro launched in 2014, INSQIN® which is a offer of waterborne and solvent-free PU coating technology for textiles. The alternative technology allowing complete substitution of dimethylformamide (DMF) normally used in this process.

Substituted substances

N,N-dimethylformamide

CAS No. 68-12-2 EC No. 200-679-5 Index No. 616-001-00-X

Chemical group

Carboxamides

Classification: hazard statements

H360D May damage the unborn child
H332 Harmful if inhaled
H312 Harmful in contact with skin
H319 Causes serious eye irritation

Reliability of information

Evidence of implementation: there is evidence that the solution was implemented and in use at time of publication
Convergent opinions: conclusions for similar cases are similar to the ones in this case study

Reason substitution

CMR

Other type of alternative

Water-based PU coating technology for textiles

Hazard Assessment

Substance to be substituted: DMF is included on the REACH restriction list, according to Article 73 of Regulation (EG) No. 1907/2006 (REACH Regulation). It is listed on the Substance Database according to SUBSPORTplus Screening Criteria (SDSC) as CMR cat. 1A or 1B. » Check the Substance Database according to SUBSPORTplus Screening Criteria (SDSC)

Description of Substitution

PU coated textile is an important class of textile material, with around four billion square meters being produced every year. It is consumed mainly by the fashion and sports footwear and apparel industries, being used in shoes, garments and accessories. Woven-/Non-Woven- or Knitted- synthetic leather is manufactured according to the “wet process”: a process that brings about the coagulation of a polyurethane resin dissolved in the solvent dimethylformamide (DMF) onto a textile backing. This process was established more than 50 years ago and remains ubiquitous. The production of these materials with the “wet process” brings several environmental concerns. Whilst polyurethane itself is a polymer widely and safely used in applications from building to refrigeration, from automobiles to mattresses, the DMF on which this process relies is labelled Toxic and recently entered the prioritization list for authorization in REACH. Its use presents health risks for workers in the mills upon exposure, as well as emission into the atmosphere. Traces up to 0.1% may remain in the coated textiles. A second concern is the energy consumption: the process generates water contaminated with DMF that must be reclaimed through distillation, requiring significant energy. Finally, the process consumes much water: it requires constant inflow of clean water to fill the coagulation and washing baths, replacing that removed for DMF reclamation. Polyurethane Dispersions (PUD) enable the manufacture of Woven-/Non-Woven- or Knitted- synthetic leather in a process quite different to the standard: it is a “dry process” that does not need the mixture of water and DMF to create the PU synthetic material base. When using PUD’s, the leather like effect is created through the application of a “foam” of PUD onto a textile or paper substrate before drying in an oven. These INSQIN® technology enables an entirely new level of sustainability in the production of the materials themselves, using no solvents at all, 95% less water and 50% less energy. Not only does this remove the pollution risk to air, water and ground; manufacturers are also assured of a safer workplace for their operatives. Considering such an environmental and social impact, the substitution of solventborne PU technology for the manufacture of PU synthetic materials clearly has the potential to transform a whole industry, one which employs workers in hundreds of factories, mostly in China. Covestro believe that disruptive innovation requires not only the right technology, but also the right kinds of collaboration in the value chain. It committed to collaboration with players all along the value chain, including directly with brand owners, thereby leveraging to the maximum the innovative potential of its technologies. This commitment extends to the provision of further value-adding services that address industry pain points. There are various fashion and retail brands, who use this technology as an alternative to solvent based PU. One is ALDI Germany, who uses the material for kids shoes.

Case/substitution evaluation

This case story from a producer describes a new technology developed to eliminate DMF used in the production of PU coated textiles.

State of implementation

In use

Date and place of implementation

2015 China

Availability ofAlternative

on the market

Producer/Provider

http://www.duksung21.com/en/

Type of information supplier

Producer / distributor

Contact

www.covestro.com

Further information

More information about the alternative technology can be found at: http://www.products.covestro.com/en/Industries/Textile/INSQIN.aspx

Date, reviewed

February 9, 2022