Rubber anti-aging additive: N,N’-Diphenyl-p-phenylenediamine

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Rubber anti-aging additives: N,N’-Diphenyl-p-phenylenediamine. Read this chapter in the novel reader. Immerse yourself in reading within the novel reader. Over time, rubber and plastic products are prone to aging issues such as cracking, hardening, and loss of elasticity, which significantly shortens their service life. N,N’-Diphenyl-p-phenylenediamine (antioxidant H/antioxidant PPD), as a p-phenylenediamine-based antioxidant, has a long history of use in the rubber and plastic processing industry and is compatible with a wide range of rubber types. Its applications also extend to fields such as optoelectronic materials and dye synthesis. With the establishment of new production capacity in China, the industry is entering a new phase of development. I. Basic physical and chemical parameters and safety properties: N,N’-Diphenylenediamine is a gray powder solid under normal conditions. There is a significant difference in solubility: it is completely insoluble in water, slightly soluble in ethanol, and readily soluble in common organic solvents such as ether, acetone, chloroform, toluene, glacial acetic acid, and carbon disulfide, which facilitates its uniform dispersion and addition in rubber and plastic compounding systems. Safety risk: It is toxic; contact with the eyes can cause severe irritation ； Prolonged skin contact can easily lead to skin allergy sensitization ； It has a strong flammability; it can burn and decompose when exposed to open flames or high-temperature heat sources, releasing toxic nitrogen-containing fumes. In storage, production, and feeding processes, it is necessary to use sealed operations, ventilation systems, protective equipment, as well as fire and explosion prevention measures. II. Applications (1) Rubber industry: In the industry, it is commonly referred to as Antioxidant H or Antioxidant PPD. It can be used directly as a rubber antioxidant on its own, or combined with Antioxidant D to achieve synergistic effects. Additionally, it serves as a crucial raw material component in the synthesis of the high-performance antioxidant 4020; thus, it occupies a key position in the industrial chain. It is compatible with the vast majority of common synthetic rubber and natural rubber systems, such as natural rubber, styrene-butadiene rubber, nitrile rubber, and butadiene rubber; upon addition, multiple protective effects are achieved simultaneously: it significantly improves the resistance of the rubber compound to fatigue from repeated bending, and prevents cracking on the surface of the products ； Enhance heat-resistant oxidation and ozone corrosion resistance ； Its key advantage is that it does not interfere with the normal vulcanization process of rubber, does not delay vulcanization or reduce the cross-linking density, making it suitable for the production of heavy-duty rubber products such as tires, hoses, and conveyor belts. (II) Plastic processing aids: Adding this product to the production and processing of polyethylene and polypropylene, which are common polyolefin plastics, can prevent the oxidation and chain scission of polymer chains, delay the aging and embrittlement of plastics, and extend the service life of plastic components, pipes, and injection-molded parts when used outdoors. (III) Extended applications in fine chemicals 1. Dye synthesis intermediates: Used as aromatic amine monomers in the synthesis of organic dyes ； 2. Preparation of photoelectric functional materials: Using N,N’-diphenyl-p-phenylenediamine as a starting material, and combining it with aryl bromides in an o-xylene solvent system, along with a catalyst and heating, a substitution reaction takes place to produce terphenylamine-type organic electroluminescent materials; these materials are important synthetic monomers in the field of new OLED photoelectric materials. III. Main industrial synthesis routes: 1. Aniline + hydroquinone route: Triethyl phosphate is used as a catalyst, and an aromatic nucleophilic substitution reaction takes place under specific temperature and pressure conditions to synthesize the target product in one step ； 2. For the dibromobenzene + aniline route: a coupling reaction takes place under the catalysis of palladium-based catalysts, resulting in a high reaction conversion rate and high product purity ； 3. Other alternative processes: N,N’-diphenyl-p-phenylenediamine can also be prepared by using three sets of raw materials – p-phenylenediamine and bromobenzene, p-chloronitrobenzene and aniline, and p-quinone and aniline – and through processes such as condensation, reduction, and addition. IV. New domestic production capacity: According to publicly available environmental impact assessment information related to this industry, the approval decision regarding the environmental impact assessment for Huayao Chemical (Lanzhou) Co., Ltd.’s new project focused on the production of high-quality fine chemicals was officially made public in February 2026. The total investment in this project is 20 million yuan. It is planned to construct a dedicated production line for 100 tons per year of N,N’-diphenyl-p-phenylenediamine. The project is equipped with a complete set of specialized production equipment, including condensation reactors, distillation reactors, product cooling tanks, aniline phase separators, and slitting machines. Once operational, it will be able to supply industrial-grade finished products on a stable basis. The establishment of this new production capacity indicates a steady and strong demand for N,N’-diphenyl-p-phenylenediamine in China’s rubber and plastic additives market, as well as a continuous expansion of the country’s overall effective production capacity. V. Summary of the industry’s overall development: N,N’-diphenyl-p-phenylenediamine boasts excellent resistance to ozone and heat-oxidative aging, making it an essential component in rubber anti-aging agents. Its ability to be used in formulations, as an intermediate for the synthesis of high-end additives, and in various applications related to optoelectronic materials ensures a long market lifecycle for this substance. The upgrading of the global rubber and plastics industry, along with the expansion of production capacity for OLED optoelectronic materials, continues to drive demand. In the future, the direction of industry advancement will focus on continuous closed-loop production, automated material feeding, closed-loop treatment of waste materials, and the production of high-purity products with low levels of impurities.