Views: 99 Author: Site Editor Publish Time: 2026-06-22 Origin: Site
Anti-hydrolysis agents are used to protect moisture-sensitive polymers from performance loss caused by water, heat, acidic by-products, and chain degradation. For materials such as PET, PBT, TPU, PU, PLA, PBAT, PA, and other ester-, urethane-, or amide-containing polymers, hydrolysis can lead to reduced molecular weight, lower mechanical strength, poor processing stability, brittleness, and shorter service life.
However, selecting an anti-hydrolysis agent is not simply a matter of choosing a general stabilizer. The right product depends on polymer chemistry, end-use environment, processing temperature, moisture level, acid value, additive compatibility, and the required performance after aging. This buying guide explains how to match carbodiimide anti-hydrolysis chemistry to different polymer types and how to evaluate the most suitable solution before production.
● Anti-hydrolysis agent selection should begin with polymer type and hydrolysis mechanism.
● Carbodiimide-based stabilizers are commonly used for polymers containing ester, urethane, or amide groups.
● PET, TPU, PLA, PBAT, PU, PBT, PA, and PC may require different anti-hydrolysis strategies.
● Monomeric and polymeric carbodiimide types may differ in activity, migration tendency, processing behavior, and long-term stability.
● Powder, liquid, emulsion, and masterbatch forms should be matched to the production process.
● The final selection should be confirmed through dosage trials, processing evaluation, and aging tests.
An anti-hydrolysis agent is an additive used to slow down polymer degradation caused by moisture, heat, and acidic decomposition products. In many industrial polymer systems, hydrolysis begins when water attacks sensitive chemical bonds in the resin backbone. This reaction can be accelerated further by elevated temperature, residual catalyst, acid end groups, or poor drying conditions during processing.
Hydrolysis is especially important in polymers containing ester, urethane, amide, or carbonate structures because these linkages can be vulnerable under humid or high-temperature conditions. Once degradation starts, chain scission may reduce molecular weight and lead to measurable changes in viscosity, tensile strength, elongation, flexibility, surface quality, and service life.
Carbodiimide-based anti-hydrolysis agent technologies are widely used because they can react with carboxyl groups and help interrupt acid-catalyzed degradation cycles. This makes them different from general antioxidants, UV absorbers, or standard heat stabilizers. Those additives may protect against oxidation, light exposure, or thermal discoloration, but they do not directly address hydrolysis in the same way. For moisture-sensitive polymer systems, an anti-hydrolysis agent is often selected as a targeted functional stabilizer rather than a general additive.
Polymer type should be the first selection factor because hydrolysis does not occur the same way in every resin. PET, TPU, PLA, PBAT, PU, PA, PC, and PBT differ in backbone chemistry, end-group structure, moisture sensitivity, processing window, and application environment. Even when two materials are both considered hydrolysis-sensitive, they may still require different carbodiimide structures, dosage levels, or physical forms.
Chemical structure determines where the main risk comes from. In polyester systems, ester bonds and carboxyl end groups are often central to degradation behavior. In polyurethane systems, hydrolysis can be influenced by whether the soft segment is polyester- or polyether-based. In polyamide systems, moisture absorption and hot humid aging behavior may be more critical than short-term extrusion stability alone.
Base resin quality also matters. Molecular weight, residual acid value, moisture content, recycled content, filler loading, and blending ratio can all change the amount and type of stabilization required. A supplier therefore usually needs more than the polymer name before recommending an anti-hydrolysis agent. The most useful starting information includes resin grade, application, process temperature, drying method, expected aging environment, and target performance after aging.
Before choosing a specific anti-hydrolysis agent, buyers should first define whether the main problem happens during processing or during long-term service.
Processing-stage degradation often appears as:
● IV drop
● Melt viscosity loss
● Chain scission
● Yellowing
● Poor extrusion stability
These problems are common when the resin contains excess moisture, high acid value, or insufficient drying before melt processing. In polyester-based materials, degradation during extrusion or molding can quickly reduce molecular weight and create unstable melt behavior. This may affect line speed, dimensional control, appearance, and final physical properties.
Long-term service degradation often appears as:
● Tensile strength loss
● Elongation loss
● Brittleness
● Surface cracking
● Adhesion failure
● Shorter service life in humid or water-contact environments
This type of failure may not be visible immediately after production. A part may pass initial inspection but decline rapidly after hot water exposure, humid heat aging, or extended storage. For this reason, the best anti-hydrolysis agent should be selected according to the dominant risk profile rather than by generic product description alone.
Hydrolysis Risk Stage | Typical Symptoms | Common Production Impact | Selection Focus for Anti-Hydrolysis Agent |
Processing stage | IV drop, melt viscosity loss, chain scission, yellowing, unstable extrusion | Poor line stability, lower output consistency, appearance defects, mechanical property loss | Fast stabilization, dispersion quality, feeding accuracy, process compatibility |
Long-term service stage | Tensile loss, elongation loss, brittleness, cracking, adhesion failure | Shorter service life, customer complaints, higher return risk, poor durability in humid conditions | Long-term hydrolysis resistance, low migration, aging stability, end-use validation |
PET and PBT are typical polyester systems that can suffer from ester bond hydrolysis, IV loss, reduced mechanical properties, and processing-induced degradation. Common applications include films, monofilaments, injection molded parts, engineering plastics, and electrical insulation materials.
For these polymers, selection usually depends on process type. Powder anti-hydrolysis agent grades may be preferred when formulation flexibility or direct compounding adjustment is required. Masterbatch can be more convenient in extrusion and molding because it simplifies feeding, reduces dust, and improves dosing consistency in continuous production.
TPU and PU systems vary widely, but polyester-based types are especially sensitive to hydrolysis. Typical failure modes include loss of elongation, reduced strength, surface defects, and accelerated aging under hot and humid conditions. Common applications include footwear, hoses, cables, films, pipes, adhesives, and synthetic leather.
For TPU compounding or PU elastomer systems, powder anti-hydrolysis agent grades are often used when formulators want direct control over dosage. Liquid grades are commonly more suitable for PU coatings, adhesive systems, and other compatible liquid formulations. In selected TPU extrusion products, masterbatch may also be practical where stable feeding and cleaner operation are important.
PLA and PBAT are moisture-sensitive polyester materials widely used in biodegradable packaging, films, sheets, and compostable compounds. Their hydrolysis behavior requires careful balance. The stabilizer must improve process and storage stability without causing unacceptable effects on application performance, cost, or downstream behavior.
For these systems, anti-hydrolysis agent selection should be based on actual formulation and end use. Broad dosage assumptions are not reliable. Instead, buyers should validate whether the chosen grade supports melt stability, acceptable mechanical retention, and target shelf-life or use conditions.
PA and nylon systems often absorb moisture and may show hydrolysis-related property loss under demanding humid heat conditions. The selection direction should focus on compatibility with the specific PA grade, processing temperature, and the required aged performance. Buyers should verify whether the additive remains stable and effective under the actual extrusion or molding window.
For PC and other engineering plastics, moisture- and heat-related degradation may lead to yellowing, property decline, or appearance concerns depending on the application. Here, the selection process should consider transparency, color control, processing temperature, and long-term aging requirements. In these applications, compatibility and visual impact may be as important as hydrolysis resistance itself.
Polymer Type | Main Hydrolysis Risk | Typical Applications | More Common Starting Form of Anti-Hydrolysis Agent | Main Evaluation Direction |
PET / PBT | Ester bond hydrolysis, IV loss, processing degradation | Film, monofilament, injection molding, engineering plastics | Powder or masterbatch | Process stability, IV retention, feeding convenience |
TPU / PU | Polyester segment hydrolysis, strength and elongation loss | Footwear, hoses, cables, films, adhesives, synthetic leather | Powder, liquid, or masterbatch | Compatibility, aging resistance, dosage control |
PLA / PBAT | Moisture-sensitive ester degradation, storage and processing instability | Biodegradable film, sheet, packaging, compostable compounds | Powder or liquid | Balance between stability, processability, and end-use performance |
PA / Nylon | Moisture absorption, humid heat degradation | Engineering parts, industrial components | Case-by-case evaluation | Compatibility, thermal stability, humid heat aging |
PC / Other engineering plastics | Moisture- and heat-related degradation, yellowing risk | Transparent or technical molded parts | Case-by-case evaluation | Transparency, color, processing temperature, aging behavior |
Monomeric carbodiimide types are often selected when high reactivity or efficient acid scavenging is needed. They may be suitable for PET, TPU, PU, PLA, PBAT, and other polyester-related systems where fast stabilization during processing is important. However, buyers should also evaluate volatility, migration tendency, odor, and regulatory requirements, especially in thin-wall, film, or appearance-sensitive products.
Polymeric carbodiimide types are often considered when longer-term stability, reduced migration, or improved durability is more important. They may be preferred for more demanding service environments or higher-performance formulations. At the same time, they should be reviewed for compatibility, viscosity influence, and dispersion quality within the specific polymer system.
The practical decision comes down to whether the application needs rapid processing stabilization, long-term aged durability, or a balance of both. Migration sensitivity, odor, transparency, and color should also be considered. Final judgment should not rely only on chemical category. Aging test data in the actual formulation remains the most reliable basis for selection.
The physical form of an anti-hydrolysis agent strongly affects how it performs in production.
● Powder: Best for flexible formulation and compounding. It allows direct dosage adjustment but requires dry handling, accurate feeding, and good premixing.
● Liquid: Best for compatible PU, coating, adhesive, and liquid systems. It can simplify addition and improve distribution in reactive formulations.
● Aqueous emulsion: Useful for selected water-based systems where direct incorporation into an aqueous phase is needed.
● Masterbatch: Best for extrusion, injection molding, film, sheet, monofilament, and production-friendly dosing. It usually offers cleaner handling and better feeding stability when the carrier is compatible.
The best form is not always the one with the highest active content. In many plants, feeding stability and process fit have more practical value than nominal purity alone.
There is no universal dosage for every polymer system. The required level of anti-hydrolysis agent depends on acid value, moisture content, molecular weight, filler content, recycled content, processing conditions, and final application environment.
Over-dosage can increase formulation cost and may create side effects such as compatibility issues, processing instability, or unnecessary changes in appearance. Under-dosage may fail to deliver meaningful hydrolysis protection. A practical screening approach is to build a dosage ladder rather than testing only one level. This allows buyers to identify the point where measurable performance improvement begins and where additional dosage brings limited value.
Before commercial adoption, the selected anti-hydrolysis agent should be validated through both lab screening and pilot production.
Suggested tests include:
● Melt viscosity
● IV retention
● Tensile strength retention
● Elongation retention
● Hardness change
● Surface appearance
● Acid value or carboxyl end group level
● Humid heat aging
● Hot water immersion
● Application-specific tests
Pilot trials are important because dispersion, feeding, residence time, and line stability can affect plant performance differently from laboratory compounding. Stabilized and unstabilized controls should always be compared under the same conditions. This helps determine whether the additive is improving real processing stability, long-term durability, or both.
Several recurring mistakes reduce the effectiveness of anti-hydrolysis agent selection.
● Selecting only by price without checking long-term value
● Ignoring polymer chemistry and using one product across incompatible systems
● Choosing an additive without knowing the resin moisture level or acid value
● Applying the same dosage to different polymers or different formulations
● Overlooking handling differences between powder, liquid, emulsion, and masterbatch
● Skipping compatibility tests with pigments, fillers, flame retardants, or other stabilizers
● Making a purchase decision without aging data
In practice, an anti-hydrolysis agent that looks economical on paper may fail if it does not match the process route or end-use environment.
Before requesting samples or placing an order, buyers should confirm the following points:
● What polymer are you processing?
● Is the base resin virgin, recycled, filled, or blended?
● Is the main problem processing degradation or long-term aging?
● What are the processing temperature and residence time?
● What is the moisture content or drying condition?
● What is the acid value or carboxyl end group level?
● Do you need powder, liquid, emulsion, or masterbatch?
● What final aging test will define success?
This checklist helps suppliers recommend a more suitable anti-hydrolysis agent and reduces trial-and-error during qualification. For industrial users working with carbodiimide stabilizer technologies, providing accurate process details is often the fastest way to narrow down suitable options. Suzhou Ke Sheng Tong New Materials Technology Co., Ltd. supplies carbodiimide-based anti-hydrolysis agent products in multiple forms for different polymer applications and processing needs.
Choosing the right anti-hydrolysis agent requires more than selecting a general-purpose stabilizer. The best solution depends on the polymer structure, processing conditions, hydrolysis risk, application environment, and final performance requirements. PET, TPU, PU, PLA, PBAT, PBT, PA, and PC may all benefit from anti-hydrolysis protection, but each system requires a different evaluation approach.
A reliable buying process should start with polymer identification, followed by chemistry matching, physical form selection, dosage screening, and aging validation. By combining the right carbodiimide chemistry with proper processing and testing, manufacturers can improve hydrolysis resistance, reduce performance loss, and extend the service life of polymer products.
Polymers containing ester, urethane, amide, or carbonate structures may require hydrolysis protection, especially when used in hot, humid, or water-contact environments.
Carbodiimide-based agents help reduce acid-catalyzed degradation by reacting with carboxyl groups and moisture-related degradation products, slowing further chain scission.
Not necessarily. These polymers differ in chemistry, processing temperature, compatibility, and end-use conditions, so product selection should be based on the specific system.
Monomeric types may offer high reactivity, while polymeric types may be considered for longer-term stability or lower migration needs. The final choice should be tested in the target formulation.
Choose based on production method. Powder offers flexibility, liquid is useful for compatible liquid systems, and masterbatch is often easier for thermoplastic extrusion or molding.
Provide polymer type, grade, processing temperature, moisture control method, application, target aging condition, and required performance after aging.
