Knowledge of woven fabric (part 4) – Learn about Formaldehyde

Formaldehyde is an organic compound with many different names such as formol, methyl aldehyde, methylene oxide, methanal, is the simplest andehyde … The chemical formula is HCHO, is a volatile organic compound and has the ability to transfer to gas in normal conditions, colorless, acrid smell, difficult to smell, very soluble in water (if this solution is about 40% by volume or 37% by weight called formon or formalin).

Formaldehyde is one of the basic industrial chemicals, very toxic but very common. Formaldehyde is widely used in textile, plastic, and plastic industries (accounting for half of total formaldehyde consumption), in paper, paint, construction, cosmetics, hair dyes, adhesives, explosives, and cleaning products, in medicine and dental products, coal paper, copier ink … as a disinfectant in agriculture and fisheries.

Formaldehyde has high antiseptic properties, so it is used in medicine to kill bacteria, disinfect and as solvents to protect laboratory samples, human body organs, embalmed … Formaldehyde easily combines with other proteins (usually food ingredients) form durable, non-rotting, non-rotting compounds, but are difficult to digest. It is this property that has been used to extend the shelf life of foods such as pho noodles, noodles, rice vermicelli, wet cakes … and even in beer to combat sediment because of its low cost.

The World Health Organization lists formaldehyde as a chemical that is harmful to human health. If the human body is exposed to formaldehyde for a long time, even high or low levels can cause serious damage to the skin and respiratory system, causing cancer of many organs in the body, especially cancer. Respiratory tract such as nose, throat, lungs, … Formaldehyde is the cause of deviations and malformation of chromosomes, infected pregnant women can affect the development of the fetus.

Formaldehyde is a potentially carcinogenic substance that has been debated since the 1980s. Since April 2004, formaldehyde has been classified as Group 3 by the International Agency for Research on Cancer (a carcinogen). to group 1 (carcinogen). However, formaldehyde is now classified as a carcinogen that remains in the EU.

Particularly, the existence of formaldehyde on fabric and clothes was discovered in 2007, after a number of Chinese mattresses and blankets sold in Australia were found to have high levels of formaldehyde. Formaldehyde exists in the fabric is entirely possible, regardless of factory textiles or traditional craft textiles. Formaldehyde exists in fabrics because it is used in dyeing and finishing processes to preserve color and create cross-linking to prevent wrinkles in the finishing stage and mold resistance. Use plastic Formalfehyde in finishing treatment to prevent creasing, mostly applied to textile products made from natural fibers such as cotton, silk … Although there are many other technologies and chemicals to replace formaldehyde, But formaldehyde is still used in the textile industry because of its low cost.

The level of formaldehyde in fabrics is not the same in countries, Japan has a strict limit that fabrics for children do not have formaldehyde and no more than 75 ppm for fabrics in direct contact with the skin. However, this limit can be considered as a technical barrier because the testing method according to ISO 14184-1998 only detects formaldehyde above 20 ppm in fabric.

European experts believe that less than 10 ppm is considered to be free of formaldehyde, from 10 ppm to 20 ppm, there may be formaldehyde in the fabric but can only be quantified when formaldehyde has more than 20 ppm, so Given that determination of formalfehyde in the fabric from 0 to 20 ppm is not real. Since then, the European Union has accepted that the limit of formaldehyde contained in fabrics is ≤ 30 ppm. In fact, it is not easy to recognize the presence of formaldehyde in a fabric because its characteristic odor can still be mixed with sizing chemicals, dyes or between different fabric materials. The identification of this chemical residue can only be done by inspection methods.

Recently, there are many countries including Vietnam, in terms of fabric quality standards do not mention formaldehyde. Consequently, shipments of clothing imported into Vietnam are not subject to this standard test. In the news, many Chinese clothes contain formaldehyde, a carcinogen that worries many people. However, according to experts, because formaldehyde has water-soluble properties, it is best to just wash clothes before you use them to clean up before using to reduce the risk of poisoning ( An experiment in Korea showed that formaldehyde residues in textile products decreased by 60% after the first wash. Over time, the formaldehyde residues in textiles will diminish as the air decomposes because it is a volatile gas.

Therefore, in order to produce fabrics or garments that can be exported to foreign markets, understanding the requirements for formaldehyde content is a matter of concern to select dye chemicals and appropriate treatment technology. , of the manufacturer.

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