Effective strategies for compound antioxidants to reduce odor during production

Compound antioxidants: "odor scavenger" in the production process

In the modern chemical industry, composite antioxidants have become an indispensable chemical additive. It is like an unknown hero behind the scenes, playing a crucial role in the production of plastics, rubbers and other polymer materials. Imagine that without the presence of composite antioxidants, our production environment could become as suffocating as a landfill. These magical small molecules can not only effectively delay the aging of materials, but also significantly reduce the odor generated during the production process, thus creating a more comfortable working and living environment for factory employees and surrounding residents.

So, what are compound antioxidants? Simply put, this is a chemical preparation composed of a variety of antioxidant ingredients. They are like "special forces" in the chemistry world, each with unique skills, but only in solidarity and collaboration can we complete complex tasks. In practical applications, composite antioxidants can effectively prevent oxidative degradation of polymer materials during high-temperature processing or long-term storage by inhibiting the generation and propagation of free radicals. This degradation reaction will not only reduce the performance of the product, but will also release a pungent odor, seriously polluting the environment and affecting the quality of the product.

This article will discuss the effective strategies of composite antioxidants to reduce odor during production. We will start from the basic principles of composite antioxidants, deeply explore their specific performance in different application scenarios, and combine research results in domestic and foreign literature to analyze how to maximize their efficacy through scientific selection and rational use. In addition, we will introduce some practical product parameters and comparison data to help readers better understand the practical application value of composite antioxidants. If you are an engineer or researcher interested in the chemical industry, or a friend who just wants to know this field, this article will definitely open your eyes!

Next, let us enter the world of compound antioxidants together and uncover the mystery behind it!

1. Basic knowledge of compound antioxidants

(I) Definition and composition

Compound antioxidant is a mixture of primary antioxidant, secondary antioxidant and other functional additives. Its main function is to prevent or slow down the oxidation reaction of polymer materials during production and use, thereby extending the service life of the material and improving processing performance. The main antioxidants are usually compounds with the ability to capture free radicals, such as phenolic antioxidants; while the auxiliary antioxidants are responsible for decomposing peroxides to prevent them from further triggering chain reactions. Common ones include phosphites and thioesters.

To illustrate this vividly, we can compare compound antioxidants to a relay race. The main antioxidant is the first player, it quickly grasps the free radicals that have just been generated and "uniform" it; the auxiliary antioxidantIt was the second player who took over the former's results and continued to deal with the peroxides that had already formed to ensure the smooth completion of the entire game. It is this clear model of cooperation that allows composite antioxidants to perform well in complex and variable chemical environments.

(Bi) Classification and Characteristics

Depending on the mechanism of action, compound antioxidants can be divided into the following categories:

Stealed phenolic antioxidants
This is a common type of main antioxidant with strong free radical capture ability. They break the oxidation chain reaction by binding to free radicals. Typical representatives include BHT (2,6-di-tert-butyl-p-cresol) and CAO-1010 (tris[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol). The advantages of this type of antioxidant are good thermal stability and low volatility, which is very suitable for material protection under high temperature processing conditions.
Phosophite antioxidants
It is mainly used as a supplementary antioxidant, which can effectively decompose peroxides and prevent them from decomposing and producing more free radicals. Common varieties include TNPP (trinolyphenylphosphite) and DOF (bioctadecylphosphite). This type of antioxidant is characterized by significant synergistic effects, which are better when used with hindered phenolic antioxidants.
Thioester antioxidants
It is also a supplementary antioxidant, mainly used to decompose peroxides and reduce carbonyl compounds. Typical representatives are DLTP (thiodipropyl dilaurate) and DSTP (thiodipropyl distearate). The advantages of thioester antioxidants are inexpensive and have good compatibility, but may cause slight odor problems in some sensitive materials.
Special functional antioxidants
With the advancement of technology, some composite antioxidants with special functions have also appeared on the market. For example, formulations containing metal ion passivating agents can effectively prevent catalytic oxidation caused by metal catalyst residues; while formulations containing ultraviolet absorbers can provide additional light stability in outdoor environments.

Category	Main Ingredients	Functional Features
Stealed phenolic antioxidants	BHT, CAO-1010	Catch free radicals, good thermal stability, low volatility
PhosophitesAntioxidants	TNPP, DOF	Decompose peroxides, and the synergistic effect is significant
Thioester antioxidants	DLTP, DSTP	Decompose peroxide, low price, good compatibility
Special functional antioxidants	Metal ion passivator, UV absorber	Provides additional protection features such as anti-metal catalytic oxidation or light stability

(III) Mechanism of action

The mechanism of action of composite antioxidants can be summarized in the following steps:

Free Radical Capture
Free radicals are generated when polymer materials are affected by heat, light or other external factors. These free radicals trigger chain oxidation reactions, resulting in a decline in material properties. The main antioxidant breaks this reaction chain by combining with free radicals to form a relatively stable product.
Peroxide Decomposition
During the oxidation process, a large amount of peroxide is often generated. If not processed in time, these peroxides will further decompose to produce new free radicals, aggravate the oxidation reaction. The auxiliary antioxidants prevent the reaction from continuing by decomposing peroxides and converting them into harmless substances.
Synergy Effect
The reason why complex antioxidants are powerful is that they make full use of the synergies between different components. For example, when hindered phenolic antioxidants and phosphite antioxidants are used in combination, the former is responsible for capturing free radicals, and the latter is responsible for decomposing peroxides. The two complement each other and jointly improve the overall antioxidant performance.

2. Advantages of composite antioxidants in reducing odor

In industrial production, the problem of odor has always been a headache. Whether it is a plastic product processing factory or a rubber manufacturing workshop, the pungent smell in the air not only affects the health of workers, but may also lead to product complaints and even customer churn. Compound antioxidants have shown unique advantages in this regard and can be regarded as a "magic weapon" to solve the problem of odor.

(I) Inhibit oxidative degradation reaction

Plumer materials are prone to oxidation and degradation reactions during processing, which releases a series of volatile organic compounds (VOCs), which are often the main sources of odor. For example, polyethylene (PE) may undergo oxidation and cracking at high temperatures, forming aldehydes, ketones and carboxylic acids, which emit the substances.The smell is unbearable.

Compound antioxidants can significantly reduce the generation of these harmful substances by inhibiting the occurrence of oxidative degradation reactions. Take hindered phenolic antioxidants as an example, which can capture them at the early stages of radical formation, thereby avoiding subsequent chain reactions. This not only reduces the emission of VOCs, but also reduces the risk of yellowing on the surface of the material.

(II) Optimize processing conditions

In addition to directly inhibiting the oxidation reaction, composite antioxidants can also indirectly reduce the generation of odor by optimizing processing conditions. For example, during injection molding, if the melt temperature is too high, the material is prone to local overheating, causing a strong odor. By adding an appropriate amount of composite antioxidant, the heat resistance and flowability of the material can be improved, making the processing process more stable, thereby reducing odor problems caused by overheating.

(III) Enhance product stability

The use of composite antioxidants is particularly important for some products that require long-term storage or exposure to harsh environments. For example, agricultural films are prone to photooxidation reactions under direct sunlight, resulting in an unpleasant odor. By adding composite antioxidants containing ultraviolet absorbers, the aging rate of the material can not only delay the material, but also effectively control the generation of odors.

Application Scenario	Common sources of odor	Composite antioxidant solutions
Plastic injection molding	High temperature oxidation and cleavage to generate VOCs	Add hindered phenolic antioxidants and phosphite antioxidants to inhibit oxidation reaction
Rubber vulcanization processing	Vulcanized by-products and incomplete reaction monomers	Use thioester antioxidants to decompose peroxides and reduce residual substances
Agricultural film	Photooxidation reaction produces aldehyde substances	Add a composite antioxidant containing ultraviolet absorber to enhance light stability

3. Selection and use strategies for compound antioxidants

Although compound antioxidants are powerful, if they are selected improperly or used incorrectly, they may be counterproductive. Therefore, in practical applications, we need to select the appropriate types of antioxidants according to specific needs and formulate scientific usage plans.

(I) Selection Principle

Select according to material type
Different types of polymer materials have different requirements for composite antioxidants. For example,Polyolefin materials (such as PE and PP) usually use hindered phenolic antioxidants, supplemented by phosphite antioxidants; while engineering plastics (such as PA and PC) require higher performance composite antioxidants to cope with higher processing temperatures and a more demanding use environment.
Consider processing technology
Different processing techniques will also affect the choice of composite antioxidants. For example, during the extrusion molding process, due to the large shear force, the material is prone to mechanical degradation, so antioxidants with good shear resistance should be preferred. In the film blowing process, attention is needed to be paid to the influence of antioxidants on the transparency of the film.
Balance cost and performance
While high-end composite antioxidants can provide better protection, their high prices may increase production costs. Therefore, when selecting a model, you should comprehensively consider the product positioning and market demand and choose a cost-effective solution.

(II) Usage Strategy

Reasonable amount of addition
The more the compound antioxidant is added, the better. Excessive use may lead to precipitation of antioxidants, affecting the appearance and performance of the product. Generally speaking, the recommended amount of addition is 0.1%~0.5%, and the specific value should be determined based on the experimental results.
Evening dispersion
The dispersibility of antioxidants has an important influence on their efficacy. If dispersion is uneven, it may lead to lack of protection in local areas, making the material more susceptible to oxidative degradation. Therefore, during the preparation of masterbatches or kneading, it is necessary to ensure that the antioxidant can be fully dispersed into the substrate.
Note compatibility with other additives
Complex antioxidants often need to be used together with other additives (such as plasticizers, stabilizers, etc.). At this time, attention should be paid to the interaction between the auxiliary agents to avoid adverse consequences due to incompatibility. For example, some halogen-containing flame retardants may react with phosphite-based antioxidants, reducing the latter's effectiveness.

4. Domestic and foreign research progress and typical case analysis

In recent years, with the enhancement of environmental awareness and the improvement of technical level, the research on composite antioxidants has achieved many breakthrough results. The following will combine typical cases in domestic and foreign literature to demonstrate the practical application effect of composite antioxidants in reducing odor during production.

(I) Foreign research trends

In the United States, DuPont has developed a new composite antioxidant formula that is specifically used in the production of automotive interior parts. This formula usesMulti-layer structure design, in which the inner layer is a high-efficiency radical capture agent and the outer layer is a peroxide decomposition agent. In this way, not only excellent antioxidant properties are achieved, but also greatly reduces odor emissions during processing. Experimental data show that after using this formula, the VOC concentration in the production workshop was reduced by more than 70%, and employee satisfaction was significantly improved.

In Europe, BASF launched a green composite antioxidant product, which is particularly suitable for applications in the food packaging field. This product is based on natural plant extracts and has good biodegradability and safety. After multiple tests and verifications, it can effectively control odor problems during processing without affecting the packaging performance and meet strict food safety regulations.

(II) Domestic research progress

In China, a study by the Institute of Chemistry, Chinese Academy of Sciences shows that by adjusting the proportion of components in composite antioxidants, their stability in high temperature environments can be significantly improved. The researchers found that when the mass ratio of hindered phenolic antioxidants to phosphite antioxidants is 2:1, the overall antioxidant performance of the system reaches an optimal state. Based on this research result, they have successfully developed a composite antioxidant product suitable for high-performance engineering plastics and have been put into industrial production.

In addition, an experiment conducted by Tsinghua University and a well-known company also proved the effectiveness of composite antioxidants in reducing odors during rubber vulcanization. By introducing a specific proportion of thioester antioxidants into the formulation, the generation of vulcanized by-products is not only reduced, but also improved the physical and mechanical properties of the final product. This achievement provides strong support for the green development of my country's rubber industry.

Research Institutions/Enterprise	Core Innovation Points	Practical application effect
DuPont (US)	Multi-layer structural design, synergistic effect of inner and outer layers	VOC concentration is reduced by 70%, employee satisfaction is improved
BASF (Europe)	Based on natural plant extracts, focusing on environmental protection and safety	Complied with food safety regulations and reduced processing odors
Institute of Chemistry, Chinese Academy of Sciences	Optimize the group allocation ratio to improve high temperature stability	Reasonably improved antioxidant performance
Tsinghua University	Introduce thioester antioxidants to improve the rubber vulcanization process	Reduce vulcanized by-products and improve product performance

V. Summaryand prospect

Through the detailed discussion in this article, we can see the important role of compound antioxidants in reducing odor during production. It has shown great potential and value from the perspective of basic theory and practical application. However, we must also recognize that the development of composite antioxidants still faces many challenges, such as how to further improve their environmental performance, reduce costs, and expand their scope of application.

In the future, with the continuous emergence of emerging fields such as nanotechnology and smart materials, the research and development of composite antioxidants will also usher in more opportunities. We look forward to seeing more innovative products coming out and contributing more to the sustainable development of the chemical industry. As the old saying goes, "Technology changes life." I believe that in the near future, compound antioxidants will become an indispensable tool in the hands of every chemical practitioner, making our world a better place!

Effective strategies for compound antioxidants to reduce odor during production

Compound antioxidants: "odor scavenger" in the production process