In the field of food processing, packaging and beverage filling, food-grade EPDM (EPDM) has become one of the preferred materials for sealing contact food equipment due to its excellent high-temperature steam resistance, ozone aging resistance and safety and non-toxicity. This paper analyzes the core value and technical advantages of food-grade EPDM from the aspects of material characteristics, compliance certification, typical application and selection guide.
1. Material characteristics of food-grade EPDM
1. Basic performance advantages
High temperature steam resistance: long-term resistance to 121℃ saturated steam (autoclave conditions), life > 5000 cycles;
Ozone aging resistance: 50pphm ozone concentration (ASTM D1149), 500h without cracking;
Elastic retention: compression permanent deformation rate (150℃×70h) < 20%, excellent resilience;
Resistance to polar media: Tolerance to alcohol, weak acid, weak alkali and cleaning agents (such as sodium hypochlorite solution).
2. Food safety
Non-toxic certification: FDA 21 CFR 177.2600, EU 10/2011 and other global mainstream food contact material standards;
Low migration: Total migration (OM) < 10mg/dm² (EU standard), no plasticizer precipitation;
Sensory neutral: no odor, no taste residue, in line with LFGB sensory test requirements.
3. Economy
The cost is only 1/3 to 1/2 of silica gel, and 1/5 to 1/4 of fluorine rubber;
The processing technology is mature, suitable for mass production (molding cycle 2~5 minutes).
2. Typical application scenarios of food-grade EPDM
1. Food processing equipment
High temperature sterilizer seal:
Resistant to 121℃ saturated steam, sealing life > 3 years (2 sterilization cycles per day);
Typical case: can production line seal ring, hardness 70±5 Shore A.
Baking Equipment:
Withstand 180℃ dry heat environment, used for oven door seal, prevent heat loss;
Resistant to starch and sugar adhesion, easy to clean design (surface roughness Ra≤0.8μm).
2. Beverage and dairy industry
Filling machinery:
Acid beverage (pH≥3.0) corrosion resistance, used for juice, yogurt filling valve seal;
In line with 3-A health standards, no dead Angle structure to avoid microbial breeding.
Beer brewing Equipment:
Withstand CO₂ penetration (air permeability < 0.5g/m²·day), to ensure the tightness of the fermenter;
Resistant to alcohol (concentration < 20%) soaking, no swelling deformation.
3. Food packaging machinery
Vacuum packaging confidential seal:
Under the vacuum degree of -0.1MPa, the elasticity is maintained, and the compression rate is 25% to 30%.
For surface coating treatment (such as PTFE spraying), the coefficient of friction is reduced to 0.1.
Heat sealing equipment:
Resistant to instantaneous high temperature (200℃×5s), used for packaging film heat sealing roller seal;
Resistant to oil penetration (e.g. fried food packaging lines).
4. Water treatment and delivery system
Drinking water pipe seal:
NSF/ANSI 61 drinking water system certification, no harmful substances precipitation;
Resistance to chlorine (concentration < 5ppm) corrosion, life > 10 years.
CIP Cleaning System:
Resistant to 80℃ hot lye (NaOH concentration < 4%) cycle washing;
Compatible with stainless steel flanges to avoid galvanic corrosion.
3. Limitations and alternatives of food-grade EPDM
1. Scenarios are not applicable
Oil food contact: EPDM will swell in vegetable oil and animal fat (volume expansion rate > 30%), need to use fluororubber (FKM);
Hydrocarbon solvent environment: not resistant to gasoline, n-hexane and other non-polar solvents;
Ultra-high temperature and dry heat: When the long-term use temperature exceeds 150 ° C, silicone or fluorine rubber is preferred.
2. Comparison of alternative materials
Material temperature resistance oil resistance cost typical scene
EPDM -50℃~150℃ difference ￥5~20/ steam sterilization, beverage filling
Silicone (VMQ) -60℃~230℃ in ￥15~50/ high-temperature baking, medical equipment
Fluororubber (FKM) -20℃~200℃ ￥30~100/ oil-containing food machinery, frying equipment
4. Selection and use guide
1. Match key parameters
Hardness selection:
Static seal: 60~80 Shore A (high contact stress);
Dynamic seal: 50~70 Shore A (low friction resistance).
Dimensional accuracy:
Inner diameter tolerance: ±0.3mm (ISO 3601-1 Class G);
Section diameter tolerance: ±0.1mm.
2. Installation and maintenance
Lubricants: Use food-grade silicone grease (e.g. Dow Corning® 111) to reduce starting torque;
Precompression: static seal recommended 20%~30%, dynamic seal 10%~15%;
Life monitoring: regular inspection of surface hardening, cracks, forced replacement when the elasticity drops 20%.
3. Supply chain certification
Select suppliers with ISO 9001 and ISO 22000 certification;
Required migration test reports for each lot (compliant with FDA/EU standards).
Conclusion: The Balance between security and economy
Food grade EPDM occupies an irreplaceable position in the non-fat food industry due to its high cost performance and reliable steam resistance. From high temperature sterilizers to drinking water pipes, it guards the health and efficiency of the global food chain with its characteristics of "safety, no migration, durability and easy maintenance". In the future, with the progress of nano-filler modification and environmentally friendly vulcanization process, EPDM will achieve breakthroughs in oil resistance and high temperature stability, and further expand its application boundaries.