Don’t buy this kind of underwear randomly, it’s really unhygienic!

The May Day holiday is coming soon, and many friends have put their travel plans on the agenda.

But it is really painful to wash your underwear by hand after a tiring day out! If you collect them and wash them at home, you are worried that bacteria and microorganisms will multiply. Therefore, many friends choose disposable underwear, which is very convenient to throw away after use.

But are disposable underwear really safe? Some netizens said that after wearing substandard disposable underwear, not only did it not become cleaner and more hygienic, but it also caused gynecological diseases, because they bought disposable underwear made from "recycled cotton".

Image source: TikTok @黑犬酱

So, as ordinary consumers, how can we choose safe and hygienic disposable underwear?

See the standard:

Look for hygiene standards + safety technology categories

1. Hygiene standards

Look for GB15979-2002 "Hygiene Standards for Disposable Sanitary Products". This standard has strict requirements for bacteria, E. coli, fungi, etc., which can show whether the disinfection requirements are met.

Image source: GB15979-2002 "Hygiene Standards for Disposable Sanitary Products"〔S〕

2. Safety technology category

Look for GB18401-2010 "National Basic Safety Technical Specifications for Textile Products". Infant textile products should meet Class A requirements, products that come into direct contact with the skin should at least meet Class B requirements, and products that do not come into direct contact with the skin should at least meet Class C requirements. Therefore, when buying disposable underwear, look for Class A or Class B.

Image source: GB18401-2010 "National Basic Safety Technical Specifications for Textile Products" [S]

3. Product standards

The product standard can show whether the disposable underwear is qualified, such as whether it is easy to break or unravel. There is currently no special national standard for disposable underwear. Most corporate standards follow the standard of GB/T8878-2023 "Knitted Underwear", which is the common underwear standard. Since the latest version of the knitted underwear standard will not be implemented until December 1, 2023, the products produced before this are still marked with the standard number of GB/T 8878-2014, as shown in the figure below↓

Image source: Screenshot of e-commerce platform

When we buy disposable underwear, we must pay attention to whether the "hygiene standards" and "safety technology categories" are marked on the packaging. Many "three-no" products do not have these two standards, and some products may only have one marked.

Look at the sterilization process:

Look for high energy electron beam sterilization

Disposable products are usually not washed and worn directly, and it is inevitable that bacteria will remain on the fabric during production. Disposable underwear itself is a product that comes into contact with private parts, so be sure to choose products that have undergone a "sterilization process."

Searching for "disposable underwear" on e-commerce platforms revealed that disposable underwear is a disaster area for "three-no" products. These disposable underwear do not have any certificates of conformity on the packaging bags, and do not even have the manufacturer's information, but they have a very high purchasing volume.

Because these products are marked "high temperature sterilized" on the product homepage, it is very confusing for consumers. Therefore, we must pay attention to the sterilization method when purchasing.

Image source: Screenshot of e-commerce platform

1. Ethylene oxide sterilization

Most disposable underwear is sterilized with ethylene oxide (EO sterilization). Ethylene oxide is a broad-spectrum sterilant that can kill various microorganisms at room temperature. This technology is very mature, and our "disposable medical masks" widely use this technology. However, it has a disadvantage that "ethylene oxide" has a peculiar smell, and if the manufacturer does not completely remove the odor, it will remain on the fabric.

Image source: Screenshot of e-commerce platform

2. High-energy electron beam sterilization

There is another sterilization process that is even better, that is "high-energy electron beam sterilization", which uses radiation to kill the residual microorganisms in the product packaging. Its advantages are thorough sterilization, safe operation, and no residue. This technology is widely used in food sterilization. For example, the "dehydrated vegetables" in the instant noodles we eat use this technology. Because there is no additional chemical sterilizer introduced, there is no odor residue.

Image source: Screenshot of e-commerce platform

Look at the craftsmanship: Look for knitting

Cheap disposable underwear is usually made of "non-woven fabrics", and the biggest advantage is that it is cheap. Its production process is similar to that of a face towel, but if you pull it a little, you will find that it is easy to lose shape or even have holes. If you rub it a few times, there will be visible lint. It is often seen in public places such as saunas and beauty salons.

The non-woven fabric used in this disposable underwear is very similar to that of "disposable masks". Its main components are polyester fiber (polyester) and polypropylene (PP). It has poor breathability and sweat absorption. After wearing it for one or two hours, it will feel stuffy and not breathable.

Image source: Screenshot of e-commerce platform

Good disposable underwear is usually made of knitted fabrics, which are the same as the weaving structure of the underwear we usually wear. The fabrics interwoven with yarns can ensure that they are not easy to lose shape when worn and fit the body better. At the same time, the yarns are tightly held together, and the linting will be much less than disposable underwear made of non-woven fabrics.

Image source: Screenshot of e-commerce platform

Look at the material:

Regenerated cellulose fiber/viscose fiber

In everyone's subconscious mind, the first reaction is definitely that cotton is the best material, but for "disposable underwear", this is not necessarily the case.

Cotton grows naturally. Due to the variety, planting area, management method and climate factors, the quality of cotton will vary. After the cotton is harvested, professional organizations will grade the cotton. Good quality cotton is usually used to make high-end home textiles, high-end shirts, etc., which can sell more products at a premium; ordinary cotton is used to make daily T-shirts and clothes to increase market sales; and inferior quality cotton is used to make disposable products, which can reasonably play its value and also achieve the purpose of low price. There are many disposable underwear on the market that are made of pure cotton, mainly medium and low count combed cotton fabrics.

Image source: Screenshot of e-commerce platform

The material that is more suitable for making disposable underwear is "regenerated cellulose fiber/viscose fiber". This material is made by dissolving "trees or cotton linters" and then spinning them, so that the molecular structure of cellulose fibers is rearranged, making the moisture absorption 50% higher than cotton itself. Secondly, "regenerated cellulose fiber" is a man-made fiber, so the length control is more stable, generally between 36~40mm, which is already the fiber length of long-staple cotton, so the fabric made is not easy to shed.

Image source: Screenshot of e-commerce platform

Since the raw materials of regenerated cellulose fiber/viscose fiber come from trees that can be planted on a large scale, the production cost is very low, usually only about 70% of the price of cotton yarn, so it is more cost-effective.

But this material has a disadvantage, that is, it is easy to tear when washed (poor wet strength), and it is also prone to shrinkage. But this huge defect is just avoided in disposable underwear, and there is no need to consider the washing situation.

Tips:

1. Can disposable underwear still be worn after being washed?

The fabrics and sewing threads of disposable underwear are usually relatively loose, and they are prone to unraveling, damage, wrinkles, etc. after washing, resulting in a significantly poor wearing experience after washing. It is not recommended to wear them after washing.

2. Is it really okay to wear disposable underwear for a long time?

It is OK to wear disposable underwear for a long time, but this long-term wearing means "wearing underwear once but changing it frequently", which will not cause the risk of bacterial growth. However, it is not recommended to wear a pair of disposable underwear for a long time, as bacteria can easily grow, and the fabric and design of disposable underwear are not designed for long-term use. It is easy to break, lose lint, and unravel after long-term wear.

Author: Yao Weiming, Textile Chemical Engineer

Audit丨Song Lidan Consulting Engineer, Industrial Research Department, China Textile Construction Planning Institute