What is the biochemical mechanism by which P-Phenylenediamine (PPD) causes allergic reactions (dermatitis)? What are the current global limits on the content of P-Phenylenediamine (PPD) in hair dyes?

What emergency measures should be taken if EA drums are found to be bulging during summer transport? How is the supplier's responsibility determined? How can gas chromatography (GC) determine whether trace impurities in ethyl acrylate (Eacrylate) will cause yellowing of the copolymer?

Is the industrial specification of P-Phenylenediamine (PPD) usually in flake or powder form? Which form is better in terms of dissolution rate and dust control?

When importing Eacrylate from China, is using OA (Open Access) 30 days or LC at sight more beneficial for buyers to avoid quality dispute risks?

What is the mainstream process for synthesizing P-Phenylenediamine (PPD)? What are the advantages and disadvantages of the reduction of p-nitroaniline and ammonolysis?

Does the supplier have bonded warehouses in Ho Chi Minh City/Rotterdam? What is the minimum lead time for emergency replenishment?

Under GHS standards, what type of environmental hazard does P-Phenylenediamine (PPD) fall under? How toxic is it to aquatic organisms?

Does the supplier commit to providing independent third-party laboratory (e.g., SGS) testing support in the event of a quality claim?