PPE

Please excuse the late arrival of this article about mask odor

Abstract: when it comes to mask odor, we have to talk about the raw materials of masks. A large part of mask odor is due to the odor of non-woven fabrics, and the odor of non-woven fabrics is due to the odor of polypropylene granules. The author found that polypropylene itself is odorless and nontoxic. So the question is, why do masks smell

today’s article, first of all, excludes the situation of expired / contaminated and fake products. We only conduct a quasi professional technical analysis on the peculiar smell of masks from regular manufacturers in the industry. Of course, this analysis combines some views of filter material suppliers, industry experts, mask manufacturers and terminal service providers in the industry, and the professional discussion part, Please refer to Yang Xianhua’s “in depth analysis of odor problem of newly bought masks” by Xiamen Bottle Technology Co., Ltd. thank you! Written hastily, welcome to discuss the message

first of all, people who are sensitive to the taste will be more sensitive to the material and taste of masks. 1n this special period, masks are concentrated for three days from production to sales to end-users, which is far less than the eight hour gamma ray radiation sterilization or 14 day analytical release of chemical residues required for odor treatment before leaving the factory, The masks bought at this node may have more peculiar smell. Because the total time from raw materials to finished products to users may be less than 14 days

“low odor” raw materials, but the requirements are very high

when it comes to mask odor, we have to say the raw materials of masks. A large part of mask odor is due to the odor of non-woven fabrics, and the odor of non-woven fabrics is due to the odor of raw material polypropylene granules. The author found that polypropylene itself is odorless and nontoxic. So the question is, why do masks smell

the material of mainstream non-woven mask is PP non-woven

the raw material of PP non-woven fabric is polypropylene. PP non-woven fabric is formed by drawing polypropylene granules or powders. The production process of polypropylene granules involves a lot of technical requirements. Due to self degradation and the use of various additives, polypropylene granules have peculiar smell

in recent years, China has achieved a high level of technology in the field of polypropylene, including polypropylene pellets from Sinopec, PetroChina and ExxonMobil. However, improving the source of raw materials can improve the odor problem of raw materials. We can only say improvement, not no smell at all

for the whole non-woven fabric industry, the number of non-woven fabrics used in masks accounts for a small proportion, while other occasions where these non-woven fabrics are used do not have very high requirements for their own odor level, so the low-cost polypropylene raw material particles “make do”. According to people in the non-woven industry, due to the fierce competition in the non-woven industry, the profit of a ton of non-woven fabrics is generally reduced to about 1000 yuan. 1f you choose good polypropylene raw materials, the cost of a ton will be increased by 500 yuan, which is equivalent to directly cutting 50% of the profit. The end result is the odor problem caused by these non-woven fabrics when used on masks

it is not only the raw material problem that masks have peculiar smell.

polypropylene will break the chain above 150 ℃ and generate a series of oxidation products, which are also one of the sources of peculiar smell. 1mproper use of additives, catalyst residues, etc., will produce odor. 1n order to control the generation of odor, we need efficient volatilization equipment, control the amount and category of additives, control the residue of catalyst, etc., so we need suppliers with considerable scale and technical conditions. Through their own unique way of processing to reduce this problem

then the problem comes, there are excellent granular materials, excellent processing granular technology, to ensure that the production of PP non-woven fabric with “low odor” level. 1f mask manufacturers get excellent “low odor” non-woven fabrics, can they solve the problem of mask odor

the answer is No

first of all, the non-woven fabric itself has a strong ability to absorb the surrounding odor. 1f it is improper in the process of storage and transportation, the non-woven fabric will have peculiar smell. The manufacturer should at least have a separate warehouse for storing non-woven fabrics and achieve good preservation, which is the first point

secondly, assuming good storage and transportation, there is another important link that can not be ignored – production problem< At present, the forming process of non-woven fabric is ultrasonic welding. When the temperature of ultrasonic welding exceeds 150 ℃, the phenomenon of thermal oxidation and complete decomposition of polypropylene exist, which oxidizes to aldehydes and ketones, resulting in peculiar smell. 1t is worth mentioning that the non-woven fabric must be melted, that is to say, polypropylene must be melted for ultrasonic welding. 1n other words, the welding temperature of the mask must be maintained at least above 160 degrees, generally 240 degrees as long as the mask can be welded, there must be a thermal oxidation temperature higher than 150 ℃ (generally 240 ℃ is the ideal thermal oxidation temperature). Thermal oxidation products and a lot of odorous small molecules must be produced at present, the problem of peculiar smell has been mentioned in the domestic detection standards, and there is no detection method to determine the gas concentration inside the mask. As we know, some of these volatile gases inside the mask are surface gas produced by non-woven fabrics, and the other part is welding gas produced by welding, and the surface gas is easy to fill the packaging bag, Ventilation can remove part of the odor on the surface. However, the welding line and other layers of cloth are wrapped and sealed in the inner layer, which can not diffuse in a short time, and the volatilization process takes a long time as a health protection product, masks should be as low as possible for pregnant women, children, the elderly and the frail, no matter the concentration. 1n this special period, the time is tight and the task is heavy. Many links are “urged” by the epidemic situation. However, the problem of peculiar smell of masks is not only highlighted at this time, but is particularly serious recently [summary at the end of the paper] there are three types of masks in the market: non-woven masks, cotton masks and printed masks 1. The reason for the peculiar smell of non-woven masks (including N95 masks) 1) the taste of raw materials used in the production of non-woven fabrics will not be repeated. At present, no country or factory in the world can solve this light smell. What we can do is to be as near as possible to tasteless. However, this flavor will gradually disappear if the raw materials and products are exposed to the air for a period of time. This kind of odor is harmless to human body 2) peculiar smell caused by adding recycled materials in the production process of non-woven fabric due to cost considerations, many non-woven fabric factories will add calcium carbonate or recycled materials in the production process of non-woven fabric to reduce costs. Some low-tech factories, because the technical level is not up to standard, resulting in the production of non-woven fabrics have a peculiar smell. Generally, this kind of peculiar smell is pungent, but the price is very low. So there are a lot of mask workshops to buy such low-end products and produce harmful masks with peculiar smell. When purchasing masks, please choose famous brands or log in to the labor insurance website(www.chinalaobao.com )Search 3) non woven activated carbon masks are easy to produce sour smell activated carbon masks are often found to have peculiar smell, mainly sour. The main reason for this flavor is that in the process of producing activated carbon non-woven fabric, activated carbon particles need to be attached to the non-woven fabric with adhesive. 1f the production technology is not up to standard a little, it will easily lead to acid taste of activated carbon non-woven fabric. This kind of odor is harmless to human body 2. The reason for the peculiar smell of the cotton mask the main reason for the peculiar smell of the cotton mask is that the cotton or cotton mask is damp and moldy in the process of keeping. This kind of odor is harmful to human body 3. The reason for the peculiar smell of the printed mask the main reason for the peculiar smell of the printed mask is the use of non environmental friendly harmful printing pigments or inks, resulting in pungent peculiar smell. This kind of peculiar smell mask mainly exists in two layers of personalized calico mask. This kind of odor is harmful to human body 4. Other reasons for peculiar smell of masks 1) some masks, especially kn95 series masks with cup shape, often use plastic headbands, and inferior plastic headbands often cause peculiar smell. This kind of odor is harmful to human body 2) the earband and headband of the mask are often made of plastic or latex, and inferior materials are easy to cause peculiar smell. This kind of odor is harmful to human body what we are concerned about is: is mask odor harmful to human body whether the mask has peculiar smell is harmful to human body depends on the situation. At the same time, it is necessary to identify which part of the mask produces the peculiar smell 1. The non-woven fabric made of pure polypropylene has a slight smell of chemical fiber, which is harmless to human body. This kind of taste, generally open the package, scatter about 2 weeks, the taste lightens or disappears 2. 1f the non-woven fabric with additives has a strong taste, it is harmful to human body 3. The acid taste of activated carbon mask is harmless to human body< 4. The peculiar smell of cotton cloth is generally harmful to human body 5. The pungent smell of printed mask is harmful to human body 6. 1f there is a peculiar smell on the hanging belt of the mask, it is harmful to some extent, but it does not touch the nose and mouth, which is relatively small in a word, the existence of peculiar smell in masks cannot be generalized. 1n addition, domestic factories with high production technology level and strong specialization have been increasing research and development efforts. Over time, the odor problem that plagues consumers will be gradually solved so, have you bought a mask

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