Liquid Phosphite Antioxidant

Introduction

Liquid phosphite antioxidants are a category of liquid auxiliary antioxidants widely used in polymer processing, including aromatic mixed phosphites, fully alkyl phenol-free phosphites, polymeric phosphites and pentaerythritol diphosphites.

Their core function is to decompose hydroperoxides generated during high-temperature plastic extrusion, injection molding and foaming, cut off the thermal oxidation chain reaction, effectively suppress yellowing, discoloration and surface fogging of products, and simultaneously passivate metal ions (Cu, Fe, Zn) to avoid catalytic aging of resins.

Classification by structure

2.1 Aromatic phenyl-containing liquid phosphites

Representative grades: DPP, TPP, THOP, DPOP, PDOP, TNPP, 1500, DTDP, 4500

2.2 Fully alkyl phenol-free liquid phosphites

Representative grades: TOP, TDP, TLP, TTDP, TFAP, DLP

2.3 Polyether polymeric phosphites

Representative grade: PDP (poly(dipropyleneglycol) phenyl phosphite)

2.4 Pentaerythritol diphosphites

Representative grades: DIPDP diisodecyl, DIPDP distridecyl

Classification by property

Low lmpurity Phosphite antioxidants

Table 1 compare table of low impurity Phosphites antioxidants

Grade Phosphorus clarity Hydrolysis

Resistance

 Volatility Odor Emission Fluidity extraction

resistance

 Max Temp
DPP 14.2% 5 poor high heavy 5 poor 180℃
TPP 10.0% 5 poor high Heavy 4 poor 200℃
PDOP 7.3% 3 moderate moderate moderate 5 Moderate 220℃
DPOP 8.4% 4 moderate moderate moderate 4 Good 220℃
PDDP 6.4% 3 best low slight 3 best 250℃
DPDP 7.8% 4 Good Low Slight 3 good 245℃

 

Selection Guide of low impurity phosphite antioxidants

For PVC Applications

  • For cost sensitive rigid transparent PVC, low-temperature processing, and waterless applications: DPP/TPP
  • For ordinary soft PVC, artificial leather, high flowability, and limited budgets: PDOP
  • For transparent films, suitable for both soft and rigid applications, not for automotive/foaming applications: DPOP
  • For automotive interiors, PU foam, low fogging requirements,
  • Extremely low fogging and water resistance: PDDP
  • Balanced high transparency and low fogging for general use: DPDP

For polyurethane applications

  • DPP, TPP, PDOP, and DPOP are not recommended for use in polyurethane form due to rapid hydrolysis, strong phenol odor, high fogging.

 

High Performance Phosphite Antioxidants

Table 2 compare table of high performance phosphites antioxidants

Grade Phosphorus anti yellow Hydrolysis Resistance Volatility Phenol Form Fluidity temp
DPP 14.2% 5 poor high phenol release Liquid best 180℃
tdd/THOP 10.9% 5 Poor High phenol release Liquid Good 230℃
TNPP 9.6% 4 Medium Medium nonylphenol after hydrolysis Liquid good 235℃
PDP/dhop 5.5% 3 Medium Medium moderate phenol release Liquid Poor 230℃
1500 5.2% 4 Good Low Trace phenol release Liquid poor 230℃
DLP 5.8% 3 good Low Phenol-free Liquid Medium 230℃
DTDP 6.0% 3 Excellent low Trace phenol release Liquid good 240℃
4500 5.0% 4 Excellent low Trace phenol release Liquid poor 260℃
618 7.8% 4 Excellent low phenol-free flake Poor 270℃

 

Selection Guide of high performance phosphite antioxidants

  • Ultra-high transparency rigid PVC, low-temperature low-cost processing, water-free and no automotive requirements: DPP, THOP
  • Rubber, no EU export, low-cost formula: TNPP (domestic sales only, export prohibited)
  • PU flexible foam, flame lamination, polyether slurry-specific: PDP, DTDP
  • Mid-range automotive interior, TNPP alternative, balancing foaming and transparency: DTDP
  • High-end general purpose, multi-material modification, recycled plastic: 1500
  • High-end vehicle low-fog interior, food-grade, high-temperature modified: 4500
  • Pure phenol-free, low-temperature cold-resistant, low-end phenol-free foaming: DLP
  • Solid plastic granulation, polyolefin/engineering plastics, food packaging, no foaming: 618
  • EU export, zero nonylphenol, low VOC mandatory requirements: DTDP > 1500 > 4500, TNPP, DPP, THOP prohibited

 

Phenol Free Phosphite Antioxidants

Table 3 compare table of phenol free phosphites antioxidants

grades TOP TDP TLP TTDP TFAP DPD
Phosphorus 7.2% 6.2% 5.8% 5.6% 5.2% ≥12%
Instant Anti-Yellowing ★★★★ ★★★ ★★★ ★★★ ★★★ ★★★★★
Hydrolysis Stability Poorest Medium Good Excellent Excellent Excellent
Volatility Highest Medium Low Low Lowest Low
extraction resistance Poor Fair Good good good best
Processing Fluidity best good best Poor Poor Poor
Low temp Storage Clear Liquid Clear Liquid easy crystallization Clear Clear Clear Liquid
Maximum temp 200℃ 220℃ 230℃ 250℃ 260℃ Above 280℃
Price Lowest Low Medium Medium High Highest
Core Positioning Low-cost general-purpose Mid-Range balance Cold-Resistant Low-Fog High-End Low-Fog Top-Grade Trialkyl All-Round Diphosphite

 

Selection Guide of phenol free phosphite antioxidants

  • Limited Budget, High-Speed ​​Wire/Regular Soft PVC, Low Fog Not Required:TOP
  • Mid-Range Cables, Elastomers, Balancing Cost and Long-Term Stability:TDP
  • Requires Cold Resistance, Mid-Range Automotive Interiors, Light-Colored Products:TLP
  • High-Temperature Polyolefins, Recycled Materials, Regular High-End Automotive Interiors: TTDP
  • Extreme Low Fog, Medical/Food, Long-Term Outdoor Use, Highest Trialkylphenol-Free Standard:TFAP
  • High-End Transparent Parts, High-Temperature Processing, Balancing Yellowing Prevention and Long-Term Water Resistance, :DIPDP

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