Views: 0 Author: Site Editor Publish Time: 2025-11-25 Origin: Site
Engineering plastics like PET, PBT, PC, PA, and EVA are the backbone of modern manufacturing, powering critical components in automotive EV battery enclosures, 5G communication devices, and industrial machinery. Their lightweight, high-strength, and cost-effective properties make them irreplaceable—but their Achilles’ heel lies in hydrolysis, a silent degradation process triggered by harsh conditions like high temperature, humidity, and cyclic moisture exposure. In EV engine bays where temperatures exceed 120℃ or outdoor electronics exposed to 95% relative humidity (RH), unprotected plastics lose up to 70% of their tensile strength within 1,000 hours, leading to catastrophic failures and costly recalls. The solution? A targeted Anti-hydrolysis Agent—a specialized additive that intercepts degradation at the molecular level, preserving material integrity and extending service life. This article dives into why these plastics fail, how Anti-hydrolysis Agents work, and how to leverage them for durable, harsh-environment-ready components.
Hydrolysis is not random—it preys on structural vulnerabilities in polymer chains. Each of these engineering plastics contains chemical groups that act as “hydrolysis hotspots,” where water molecules (H₂O) break molecular bonds and trigger a self-accelerating degradation cycle.
Initiation: Water infiltrates the polymer matrix, attacking ester groups (PET/PBT/EVA), amide groups (PA), or carbonate groups (PC). For example, in PET, ester bonds (–COO–) react with H₂O to split into carboxylic acids (–COOH) and polyol fragments.
Acceleration: Carboxylic acid byproducts act as catalysts, speeding up bond cleavage. A single acid molecule can break hundreds of additional polymer chains, creating a “snowball effect” of degradation.
Failure: Chain scission reduces molecular weight, leading to brittleness (PET/PBT), dimensional instability (PA), or transparency loss (PC). EVA, used in 5G antenna insulation, loses flexibility and electrical insulation properties as hydrolysis progresses.
Each polymer faces unique hydrolysis risks, tied directly to its chemical structure:
PET/PBT: Ester groups are highly susceptible to water attack. Unprotected PBT gears in industrial pumps lose 50% of their impact resistance after 6 months in 85℃/85%RH environments .
PA (Nylon): Amide groups absorb moisture readily—PA66 connectors can absorb 8-10% of their weight in water, causing 20% dimensional swelling and electrical conductivity spikes .
PC: Carbonate groups degrade under acidic or humid conditions, leading to “stress cracking” in EV battery enclosures exposed to electrolyte vapors .
EVA: Low crystallinity makes it permeable to water, risking insulation failure in outdoor wiring and 5G base station components .
An Anti-hydrolysis Agent is a reactive additive designed to disrupt the autocatalytic cycle by neutralizing harmful byproducts or repairing broken chains. Not all agents are equal—effective formulations are tailored to the polymer’s structure and the harsh conditions it faces. Below are the three primary types, their mechanisms, and compatibility with target plastics:
| Type of Anti-hydrolysis Agent | Key Mechanism | Suitable Engineering Plastics | Core Advantages |
|---|---|---|---|
| Carbodiimide-based | Reacts with carboxylic acids to form stable urea linkages, eliminating catalysts for further hydrolysis | PET, PBT, EVA | High reactivity, sulfur-free, no discoloration |
| Epoxy-based | Cross-links with carboxyl/hydroxyl groups to “repair” broken chains and reduce moisture permeability | PA, PC | Enhances mechanical strength while preventing hydrolysis |
| Composite Formulations | Blends carbodiimides, epoxies, and antioxidants for synergistic protection against hydrolysis + UV/heat | PC/PA alloys, EVA | Multi-environment resistance (e.g., EV underhood + outdoor exposure) |
Our proprietary Bio-SAH™ series exemplifies this tailored approach: monomeric carbodiimides (Bio-SAH™ 362Powder) for PET/PBT, polymeric carbodiimides (Bio-SAH™ 372N) for PA, and water-soluble liquid variants (Bio-SAH™ 342Liquid) for EVA. All are manufactured via an isocyanate condensation process, ensuring ≥99% purity and no sulfur residues—critical for aesthetics and performance in visible components like PC dashboard panels .
To maximize durability, the Anti-hydrolysis Agent must align with the polymer’s chemistry and application. Below are proven strategies for each target plastic, backed by 2024 industry test data:
PET and PBT rely on ester bonds for strength, making them prime candidates for carbodiimide-based Anti-hydrolysis Agents. These agents scavenge carboxylic acids before they trigger autocatalysis.
Recommended Agent: Bio-SAH™ 362Powder (monomeric carbodiimide, ≥99% purity).
Optimal Addition Level: 1.0–3.0% by weight.
Performance Impact: In accelerated aging tests (1,000h at 85℃/100%RH), PBT with 2% Bio-SAH™ 362Powder retained 92% of its tensile strength, compared to 38% retention in unprotected PBT .
Key Applications: EV battery cooling pipes, industrial gear wheels, and PET beverage packaging molds.
PA’s amide groups absorb moisture, so Anti-hydrolysis Agents here must both neutralize acids and reduce water permeability.
Recommended Agent: Bio-SAH™ 372N (polymeric carbodiimide, ≥12% reactive content) + epoxy co-additive.
Optimal Addition Level: 1.5–2.5% for PA6; 2.0–3.0% for PA66.
Performance Impact: PA6 connectors treated with Bio-SAH™ 372N showed <7% weight gain after 500h in 95℃ boiling water, compared to 15% in untreated PA6. They also maintained CTI 600V insulation ratings, critical for EV high-voltage systems .
Key Applications: EV battery enclosures (paired with Tepex composites ), automotive underhood sensors, and water pump impellers.
PC’s carbonate groups degrade under humidity and chemicals, so Anti-hydrolysis Agents must preserve transparency while preventing stress cracking.
Recommended Agent: Bio-SAH™ composite blend (polycarbodiimide + UV stabilizer).
Optimal Addition Level: 0.8–1.5%.
Performance Impact: PC EV headlight lenses with the composite agent retained 98% transparency after 2,000h of 85℃/85%RH aging, vs. 75% in unprotected PC. They also resisted cracking when exposed to battery electrolyte vapors .
Key Applications: EV light covers, 5G router enclosures, and medical device housings.
EVA’s low crystallinity demands an Anti-hydrolysis Agent that disperses uniformly without disrupting flexibility.
Recommended Agent: Bio-SAH™ 342Liquid (water-soluble polymeric carbodiimide).
Optimal Addition Level: 0.5–1.5%.
Performance Impact: EVA 5G antenna insulation with 1% Bio-SAH™ 342Liquid retained 90% of its elongation at break after 1,500h of outdoor exposure, compared to 45% in untreated EVA .
Key Applications: Outdoor wiring insulation, solar panel backsheets, and automotive gaskets.
The value of an Anti-hydrolysis Agent is measured in real-world performance. Below is a comparison of unprotected vs. agent-treated plastics across key harsh-environment tests, using data from 2024 industry trials :
| Test Condition | Plastic Type | Unprotected Plastic | Plastic + Anti-hydrolysis Agent (Bio-SAH™) |
|---|---|---|---|
| 1,000h @ 85℃/85%RH: Tensile Strength Retention | PBT | 38% | 92% (2% 362Powder) |
| 500h @ 95℃ Boiling Water: Weight Gain | PA6 | 15% | 6.8% (2% 372N) |
| 2,000h Outdoor Exposure: Elongation Retention | EVA | 45% | 90% (1% 342Liquid) |
| 1,500h @ 120℃/60%RH: Transparency Retention | PC | 75% | 98% (1% Composite Blend) |
EV Battery Enclosures: A leading automaker replaced unprotected PA6 with PA6 + Bio-SAH™ 372N for battery housings. Field tests showed the treated enclosures withstood 3 years of underhood exposure (temperatures up to 140℃) without cracking, compared to 18-month failures in the original design .
5G Base Stations: EVA insulation treated with Bio-SAH™ 342Liquid maintained electrical resistance above 10¹² Ω in tropical environments (90% RH, 40℃) for 2 years, eliminating signal dropouts caused by hydrolysis-induced conductivity .
Industrial Pumps: PET impellers with 2% Bio-SAH™ 362Powder operated continuously in 80℃ water for 5,000 hours, vs. 1,200 hours for unprotected impellers .
Choosing the right Anti-hydrolysis Agent requires balancing polymer chemistry, environmental conditions, and processing needs. Follow this framework to avoid costly mismatches:
Ester-based plastics (PET/PBT/EVA): Prioritize carbodiimide-based agents (e.g., Bio-SAH™ 362Powder, 342Liquid) to neutralize carboxylic acids .
Amide-based plastics (PA): Use polycarbodiimides or epoxy blends (e.g., Bio-SAH™ 372N) to block moisture absorption and acid catalysis .
Carbonate-based plastics (PC): Opt for composite agents with UV stabilizers to preserve transparency and prevent stress cracking .
High-temperature environments (≥120℃): Select thermally stable agents (e.g., Bio-SAH™ 372N, TGA loss <5% at 330℃) to avoid decomposition during processing or use.
High-humidity/chemical exposure: Choose water-insoluble agents (e.g., Bio-SAH™ 362Powder) for PET/PBT, or water-soluble variants (e.g., 342Liquid) for EVA formulations that require aqueous processing .
Dry blending/extrusion (PET/PBT/PA): Use solid crystalline agents (e.g., Bio-SAH™ 362Powder) for uniform dispersion without clumping.
Liquid formulations (EVA adhesives): Opt for liquid agents (e.g., Bio-SAH™ 342Liquid) that mix seamlessly with molten polymers .
High-shear injection molding (PC): Avoid low-melting-point agents that degrade under shear; select composite blends with melt points >200℃.
Food-contact plastics (PET/PA): Choose FDA-certified agents (e.g., Bio-SAH™ 362Powder) to comply with 21 CFR §177.1520.
Electronics (PC/EVA): Ensure RoHS/REACH compliance (no heavy metals, phthalates) for global market access.
Even the best Anti-hydrolysis Agent fails without proper integration. Follow these steps to maximize performance:
Start with the lower end of the recommended range (e.g., 1.0% for PET) and scale up based on aging tests. Over-adding (>3.0%) can reduce impact strength—for example, PA6 with 4% agent showed a 15% drop in Izod impact resistance .
Use masterbatch blending (20–30% agent concentration) for consistent dispersion, especially in high-volume production.
Carbodiimide agents degrade above 280℃—keep extrusion temperatures <270℃ for PET/PBT.
Epoxy-based agents for PA react best at 230–250℃; avoid overheating to prevent cross-linking errors .
Conduct accelerated aging per ASTM D570 (water absorption) and ISO 4611 (aging).
Test mechanical properties (tensile strength, elongation) before and after aging to confirm retention >85%—the threshold for “durable” harsh-environment components.
Two transformative trends are shaping the role of Anti-hydrolysis Agent in engineering plastics: the rise of EVs/5G and the push for sustainability.
EV Battery Systems: As automakers shift to plastic battery enclosures (replacing metal ), PA/PC alloys need Anti-hydrolysis Agents that resist electrolyte vapors and 150℃+ temperatures. Our Bio-SAH™ composite blend is now specified by two Tier 1 EV suppliers for 2025 models.
5G Electronics: EVA insulation in mmWave antennas faces both humidity and UV exposure. Multifunctional agents (anti-hydrolysis + UV stabilization) are becoming standard—reducing additive load while boosting performance .
Circular Economy: Anti-hydrolysis Agents extend plastic service life by 2–3x, reducing replacement waste. A 2024 study found that PA6 components with Bio-SAH™ had a 60% lower carbon footprint than unprotected parts (fewer replacements = less manufacturing energy) .
Bio-Based Plastics: Emerging bio-based PA (derived from castor oil ) and PET require tailored agents—our Bio-SAH™ 372N is compatible with these materials, retaining 90% of their biodegradability while preventing premature hydrolysis.
Low-Addition Formulations: New polymeric carbodiimides (e.g., Bio-SAH™ 372N) deliver full protection at 1.0–1.5%, down from 2.0–3.0% for traditional agents—cutting costs and reducing polymer modification.
Synergistic Blends: Combining anti-hydrolysis agents with antioxidants (e.g., Irganox 1010) creates a “shield” against both hydrolysis and thermal oxidation, critical for EV underhood components .
For engineering plastics like PET, PBT, PC, PA, and EVA, harsh environments are no longer a barrier—they’re a challenge solved by the right Anti-hydrolysis Agent. By neutralizing hydrolysis catalysts, repairing broken chains, and adapting to polymer-specific needs, these agents transform vulnerable materials into durable, long-lasting components. Whether you’re designing an EV battery enclosure that withstands 3 years of underhood heat or a 5G antenna that performs in tropical humidity, the Bio-SAH™ series delivers the purity, reactivity, and compatibility required to stay ahead of industry demands. In a market where reliability equals competitiveness, investing in a high-performance Anti-hydrolysis Agent isn’t just an add-on—it’s the foundation of durable, future-ready products.
A: PET, PBT, PC, PA, EVA—they’re prone to hydrolysis in harsh conditions.
A: Stops hydrolysis, retains mechanical properties, extends service life.
A: Match plastic type (e.g., 362Powder for PET) and environment.
A: Some (like Bio-SAH™ 362Powder) are FDA-certified for food contact.
A: E.g., PBT retains 92% tensile strength (vs. 38% unprotected).
