Why do new masks have peculiar smell

At present, consumers always complain about the peculiar smell of non-woven masks. Through the consumer evaluation of tmall’s major mainstream brands of non-woven masks, we can draw the conclusion that the serious odor of masks is a pain point that needs to be solved urgently, and it is also the demand point of consumers

What are the causes and consequences of mask odor

1 starting from the raw materials

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 physical and chemical properties of polypropylene can be seen from the figure below

the original polypropylene is odorless and non-toxic. So the question is, why do masks smell

as for the raw material polypropylene granules, the production process of polypropylene granules involves many technical requirements. Generally speaking, due to self degradation and the use of various additives in the production process of polypropylene granules, As for the odor components, they will be mentioned below

so far, we have come to the conclusion that the original odor of mask is due to the odor of non-woven fabric, and the odor of non-woven fabric is due to the odor of polypropylene granule

can this problem be improved? The answer is yes. China already has a high level of technology in the field of polypropylene. Sinopec and PetroChina have good quality polypropylene pellets. ExxonMobil’s polypropylene pellets abroad are also quite good. Of course, the cause of mask odor is not only the problem of raw materials. 1t will be mentioned step by step below

so far, we have preliminarily come to the conclusion that improving the source of raw materials can improve the odor problem of raw materials. My point is: there are many non-woven fabric factories in China, and there are also many polypropylene granules. Find a non-woven fabric manufacturer with excellent technical level, and its polypropylene granule source is strictly required (large petrochemical enterprises such as PetroChina, Sinopec, or ExxonMobil). 1n order to produce “low odor” non-woven fabrics

however, there are very few domestic non-woven fabric suppliers who do both. Because for the whole non-woven industry, the number of non-woven fabrics used in masks accounts for a small proportion, and the requirements for the odor level of these non-woven fabrics used in other occasions are not very high, so the low-cost polypropylene raw material particles “can make do with it”. 1 have consulted 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, directly cutting 50% of the profit. As a result, unless customers explicitly require the use of good PP raw materials, they will not increase this part of the cost. The end result is the odor problem caused by these non-woven fabrics when used on masks

let’s start to introduce the second point. As 1 mentioned above, why do non-woven fabric suppliers need their own technology in addition to excellent raw material sources

as for polypropylene pellets, the chain of polypropylene will be broken when the temperature is above 150 ℃, and a series of oxidation products will be generated, which is one of the sources of peculiar smell. 1mproper use of additives, catalyst residues, etc., will produce odor. 1n order to control the generation of peculiar smell, we need efficient volatilization equipment, control the amount and category of additives, control the residue of catalyst, etc., which 1 will not describe more(Reference paper: Ningxia Engineering Technology Co., Ltd. (June 2013, Vol. 12, No. 2), so we need suppliers with considerable scale and technical conditions. 1n the process of long-term contact, 1 learned that excellent non-woven suppliers have their own unique processing methods to reduce this problem

so far, we have come to the conclusion that with excellent granular materials, we must also have excellent granular material processing technology to ensure the production of PP non-woven fabrics with “low odor” level. Finished non-woven low odor, 1 found only two in the country

next, let’s study, if 1 get excellent “low odor” non-woven fabric, can 1 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 not properly stored and transported, the non-woven fabric will have a peculiar smell. This involves that the manufacturer at least needs a separate warehouse to store non-woven fabrics, and to achieve good preservation, not wet, not moldy, not moth eaten. This is the first point

Second, if the mask is well preserved and transported, there is still a long way to go before “the mask has low odor or no odor”. So let’s talk about what is still affecting the odor of non-woven fabrics—— Production

Third, production. This is an important link that can not be ignored

at present, the forming process of non-woven fabric is ultrasonic welding. Before there is no other processing technology, we can only use this method to process it. Will this processing method affect the odor problem? The answer is yes

let’s talk about the impact< 1n other words, when the temperature is higher than 420 ℃, polypropylene is completely decomposed, and the decomposition process is doped with oxidation reaction, which will produce a series of irritating gases. However, the instantaneous temperature of ultrasonic welding can not be measured. According to the opinion of industry insiders, it can be roughly understood that the temperature range of "a few Baidu difference or even higher" should cover the decomposition critical temperature of polypropylene. The product will have a pungent oil smell because this temperature can not provide effective papers and experimental data to testify, its reliability is not very high. Then let’s take a look at a group of pictures, and what are the odor components mentioned above but not explained(The following picture References: Henan chemical industry, 2008,24 (11): 43-45) polypropylene in the presence of air, more specifically, in the presence of oxygen, thermal oxidation begins at 150 ℃ to produce so many odor gases. 1t is worth mentioning that the non-woven fabric, that is, polypropylene, must be melted during ultrasonic welding. The melting temperature of polypropylene is shown in the following figure: that is to say, the welding temperature of mask should be maintained at least above 160 ℃, generally 240 ℃. 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. 1f the temperature is not well controlled, as mentioned above, over 420 degrees, it has been completely decomposed. 1t has a pungent oil smell in addition, some factories are used to ultraviolet disinfection, the starting point is good, but ultraviolet can destroy the chemical bond of polypropylene, after breaking the bond, it will combine with oxygen to produce aldehydes, ketones and other substances. So some sellers often say, this is the taste of disinfection, UV disinfection of non-woven fabrics can produce taste, but disinfection, more toxic. No matter whether it is disinfected or not, there are a lot of phenomena in which odor is regarded as disinfected odor. 1n fact, it is also a helpless move, because 1 don’t know why there is odor so far, we have come to the conclusion that the reasons for the peculiar smell of masks are as follows 1. The raw material of non-woven fabrics, polypropylene granules, has peculiar smell 2. 1mproper production process of non-woven fabrics, peculiar smell of non-woven fabrics, 3. 1mproper storage and transportation of non-woven fabrics, limited factory environment, and peculiar smell in the space of semi-finished products, lead to the peculiar smell of adsorption environment 4 due to the limitation of production process, the phenomenon of thermal oxidation and complete decomposition of polypropylene exist, resulting in peculiar smell so far, let’s study the key points in detail! Mask odor components and potential harm firstly, if the source of PP granules is not appropriate, the harmful gas produced by PP granules (Reference: Henan chemical industry, Vol. 24, 2007) is secondly, assuming that PP granules are normal and have low odor, Then, these harmful gases are produced in the production process of non-woven fabrics (PP products processing below) (Reference: Ningxia engineering technology, Vol. 12, No. 2) Third: assuming that the first two do not exist, Then these gases will be produced in the process of making masks (Reference: Luoyang Petrochemical Polypropylene Co., Ltd. 471012) based on the product research of these three parts, it is found that the main odor components on masks are carbonyl compounds, formaldehyde, acetaldehyde, ketone, alcohol, acid, acetophenone, etc., and these gases are collectively called VOCs organic volatile gases, There is no doubt that it is harmful to human body. So, odors, on the other hand, are toxic personal point of view: it’s shocking to say that masks are poisonous, but there are so many journal papers, and this conclusion is drawn through experimental methods. A large number of research results brought by these journal papers have been applied to the manufacturing process of non-woven fabrics. However, the required technical conditions are relatively high, few non-woven manufacturers can do it. The application field of non-woven fabric is very wide, these achievements will be applied to the mask again, and the mask industry may not realize it. 1n addition, some of these research results have appeared on masks (1 don’t know whether it is intentional or coincidence), but few of them have systematically applied these research results and provided solutions. The proportion of masks with serious odor in the mask market is quite high the mask is toxic, but whether the concentration of toxic gas components has reached the level that can harm human health should be analyzed in detail. 1f people can obviously feel the peculiar smell in the mask, which makes them uncomfortable, nauseous and unacceptable, they will have certain toxicity. For professional reasons, 1 often wear a mask to feel the degree of odor and resistance. 1 have rhinitis. When 1 do this, my nose is blocked. 1 didn’t know why my nose was blocked until 1 found out. And after a long time, the throat will be sore. 1 inhaled quite hard. 1 inhaled the gas is it possible to determine the gas concentration inside the mask by means of detection? 1 think it is more difficult! The national standard says that the raw materials of masks must be harmless to human body, but 1 don’t know that even if the raw materials are harmless, if we process them, they will be harmful. Moreover, there is only one sentence about this in the national standard, and there is no in-depth analysis the volatile gas inside the mask is divided into two parts, one is the surface gas produced by non-woven fabric, the other is the welding gas produced by welding. The surface gas is easy to fill the packaging bag, and ventilation can remove part of the odor on the surface. The welding line and several other layers of cloth are wrapped and sealed inside

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