ARADUR 435

ARADUR 435 is a waterborne polyamidoamine-adduct epoxy curing agent developed for primers, waterborne coatings and waterborne adhesive systems that require strong adhesion to both the substrate and subsequent coating layers. The commercial grade is supplied as an approximately 49-51% solids polyamidoamine adduct in water with approximately 13,000-23,000 mPa·s viscosity at 25°C, 160-200 mg KOH/g amine value and an active-hydrogen equivalent weight of approximately 250 g/eq. ARADUR 435 is particularly useful in solvent-free or low-solvent, force-dried dispersion coatings for metallic and mineral substrates, and its aqueous delivery form supports low-emission coating and adhesive technologies without conventional organic solvent in the curing-agent component.

PRODUCT IDENTITY

Product name: ARADUR 435
Product type: Waterborne epoxy curing agent / hardener
Chemical family: Polyamidoamines
Specific chemistry: Polyamidoamine adduct dissolved in water
Carrier: Water
Physical form: Liquid
Appearance: Liquid
Odor: Amine
Color: Gardner ≤10
Solids content: Approximately 49-51% by weight
Water content: Approximately 49-51% by weight in dedicated technical data
Viscosity at 25°C: Approximately 13,000-23,000 mPa·s
Amine value: Approximately 160-200 mg KOH/g
Active hydrogen equivalent weight: Approximately 250 g/eq
Density at 20°C: Approximately 1.04 g/cm³
Flash point: Minimum approximately 200°C by Pensky-Martens closed-cup testing
Reference gel / pot-life range in selector literature: Approximately 90-120 minutes with the specified comparative waterborne resin system
Reference mix ratio with ARALDITE PY 33757: Approximately 100:140 parts by weight resin to hardener
Reference mix ratio with ARALDITE PZ 33757/67: Approximately 100:95 parts by weight resin to hardener
Acceptable reference-ratio deviation: Up to approximately ±10% depending on desired properties
Higher hardener proportion: Tends to increase flexibility and adhesion
Lower hardener proportion: Tends to improve chemical resistance
Primary functions: Curing agent and hardener
Primary current end uses: Primers, waterborne adhesives and waterborne coatings
Primary material compatibility: Metal substrates and mineral substrates
Primary current product feature: Excellent adhesion
Current labeling claims: Organic-solvents-free and solvent-free in the sense of no conventional organic solvent in the commercial hardener
Selector-family claim: Published selector literature identifies ARADUR 435 as benzyl-alcohol-free
Historical application positioning: Civil engineering, industrial maintenance and marine coatings
Historical dedicated application guidance: Solvent-free or low-solvent, force-dried dispersion coatings with relatively low binder content
Reference working time with ARALDITE PY 33757 dispersion coating: Maximum approximately one hour before a distinct decline in gloss and chemical-stress resistance is expected
Reference phase-stability note: In the PY 33757 dispersion system, separation into organic and aqueous phases may occur after approximately two hours
Water-dilution appearance: Further dilution with water can produce a milky appearance; this is not necessarily critical in pigmented formulations
Adhesive-primer function: Particularly suitable where adhesion is required both to the substrate and to the following coating
Storage temperature: Approximately 2-40°C
Freezing guidance: Historical dedicated technical guidance states that storage temperature should not fall below 0°C
Storage condition: Dry place, preferably sealed original container, protected from direct sunlight
Historical shelf life: At least approximately three years under the stated storage conditions, subject to the expiry date on the original container
Hazardous decomposition products in fire: Carbon monoxide, carbon dioxide, nitrogen oxides and other toxic gases and vapors
CAS Number: Commercial waterborne polyamidoamine-adduct mixture; no single CAS number should be assigned to the complete trade grade without the current SDS
EC Number: Commercial mixture; no single EC number should be assigned to the complete trade grade without the current SDS
Molecular Formula: Not applicable to the complete commercial mixture
Molecular Weight: Variable / not applicable as one fixed value

Synonyms: ARADUR 435, Waterborne Polyamidoamine Adduct, Aqueous Polyamidoamine Epoxy Hardener, Waterborne Epoxy Curing Agent, Polyamidoamine Epoxy Hardener, Waterborne Primer Hardener, Aqueous Adhesive Hardener, Waterborne Coating Hardener, Organic-Solvent-Free Epoxy Hardener, Benzyl-Alcohol-Free Polyamidoamine Hardener, Adhesive-Primer Curing Agent, Industrial Waterborne Epoxy Hardener, Mineral-Substrate Epoxy Hardener, Metal-Substrate Epoxy Hardener
ARADUR 435 should be treated as a proprietary commercial polyamidoamine-adduct solution rather than as one pure molecular substance. The active curing phase contains a distribution of amide- and amine-containing structures dispersed or dissolved in water, so one molecular formula, molecular weight or universal product CAS number would not accurately represent the grade as supplied. The current product-specific SDS should control formal component identity, concentration ranges, hazard classification and transport information.

WHAT IS ARADUR 435?

ARADUR 435 is a waterborne polyamidoamine-adduct curing agent designed for two-component epoxy systems. It combines the adhesion and flexibility associated with polyamidoamine chemistry with aqueous delivery and pre-adduct modification.
The commercial product contains approximately half active solids and half water. This makes it suitable for waterborne coatings and adhesives where conventional organic solvent in the hardener is undesirable.

A defining characteristic is excellent adhesion. ARADUR 435 is particularly suitable as an adhesive primer because it can provide good bonding to the substrate and also to the coating applied afterward.
The product is compatible with both liquid epoxy-resin systems and pre-emulsified epoxy-resin systems when the formulation is designed correctly. Historical reference systems include ARALDITE PY 33757 and ARALDITE PZ 33757/67.
ARADUR 435 is especially useful in pigmented primers, protective coatings and adhesive applications where film continuity, substrate wetting and intercoat adhesion are more important than extremely low viscosity.

POLYAMIDOAMINE ADDUCT CHEMISTRY

Polyamidoamines are amine-functional curing agents containing both amide and amine functionality. Their molecular architecture is commonly associated with strong adhesion, flexibility, toughness and relatively forgiving cure behavior.
An adducted polyamidoamine has undergone controlled pre-reaction before final use. Pre-adduction modifies compatibility, molecular size, surface behavior and the distribution of free amine functionality.

The resulting hardener still contains reactive amine hydrogens capable of opening epoxy rings and creating a crosslinked thermoset network.
The aqueous form of ARADUR 435 adds another design requirement: the curing-agent phase must remain compatible with water while still reacting efficiently with the more hydrophobic epoxy resin.
Because the active phase is polymeric and compositionally distributed rather than a single pure molecule, performance parameters such as AHEW, amine value, viscosity and solids are more meaningful than a single structural formula.

HOW EPOXY CURING WORKS

Epoxy resins contain reactive oxirane rings. Primary and secondary amine hydrogens in ARADUR 435 attack these rings and open them, forming carbon-nitrogen bonds and hydroxyl groups.
Repeated reaction between multifunctional epoxy resin and multifunctional amine hardener creates a three-dimensional thermoset network.
The mixed system gradually advances from a fluid or dispersed state through viscosity increase and gelation into a solid cured coating or adhesive.
In a waterborne system, chemical cure occurs together with physical water removal and film formation. The aqueous carrier must leave while resin particles or resin domains form a continuous phase.
Final adhesion, chemical resistance, mechanical strength and water resistance continue developing after the coating first feels dry.

SOLIDS CONTENT

ARADUR 435 is approximately 49-51% solids by weight. Dedicated technical data also list water content at approximately 49-51%.
This near-equal balance of active hardener and water means the commercial product introduces a significant aqueous phase into the formulation.
Solids content directly affects stoichiometry because equal wet weights of different waterborne hardeners can contain very different amounts of reactive material.
A lower-than-normal solids value would introduce more water and less active hardener at the same wet weight, while a higher value would increase active concentration and usually increase viscosity.
Incoming quality control should therefore consider solids or water content together with viscosity and amine value.

WATERBORNE CHARACTER

Water is the carrier for ARADUR 435. The commercial hardener does not rely on conventional organic solvent for delivery.
This supports waterborne coating and adhesive technologies with reduced conventional solvent emission and lower flammability than solvent-cut amine hardeners.
Waterborne does not mean that water has no effect on processing. Carrier water must evaporate or redistribute appropriately during film formation.
High relative humidity, low temperature and poor ventilation can slow drying even when the chemical epoxy-amine reaction is progressing.
Waterborne formulation therefore requires control of both chemical cure and physical film formation.

VISCOSITY

ARADUR 435 has a viscosity of approximately 13,000-23,000 mPa·s at 25°C.
This makes it a moderately high-viscosity waterborne curing agent compared with more fluid aqueous polyamine grades.
Viscosity affects pumping, metering, mixing and final let-down. Temperature should be standardized because cold material becomes thicker and warm material becomes more fluid.
Additional water can reduce application viscosity, but excessive dilution increases drying demand and can affect film build or dispersion stability.
Viscosity should therefore be controlled together with solids, water level and final application method.

AMINE VALUE

The published amine value is approximately 160-200 mg KOH/g.
Amine value is a titration-based measure of total basic amine functionality expressed as equivalent potassium hydroxide.
It is useful for product identity and batch consistency.
A significant shift can indicate contamination, concentration change or chemical alteration.
Amine value should not be used as a substitute for AHEW because basic nitrogen and reactive-hydrogen equivalents are related but not identical measurements.

ACTIVE HYDROGEN EQUIVALENT WEIGHT

ARADUR 435 has an active-hydrogen equivalent weight of approximately 250 g/eq as supplied.
AHEW represents the mass of commercial hardener required to provide one equivalent of reactive amine hydrogen.
The value includes the commercial aqueous form and should be used consistently with resin EEW when estimating theoretical stoichiometry.
Published reference ratios are generally more useful when the exact resin is known because resin solids, EEW and emulsification state influence the practical formulation.
The approximately 250 g/eq value helps explain why relatively high wet-hardener levels are used in the liquid-resin reference system.

DENSITY

The typical density of ARADUR 435 is approximately 1.04 g/cm³ at 20°C.
Density is useful for manufacturing calculations and conversion between weight and volume.
Stoichiometric dosing should preferably be controlled on a mass basis because resin and hardener densities differ.
Volumetric equipment should be calibrated using actual product density and temperature.
Density also provides a secondary physical quality-control check when evaluated together with water content, viscosity and amine value.

FLASH POINT

The typical flash point is at least approximately 200°C by Pensky-Martens closed-cup testing.
This very high value is consistent with an aqueous curing-agent solution free from conventional organic solvent.
The high flash point substantially reduces conventional flammable-solvent handling concerns compared with xylene- or alcohol-cut polyamidoamine solutions.
The organic polymeric amine fraction can still burn or decompose under severe heating.
Fire response and decomposition precautions should follow the current product-specific SDS.

COLOR AND APPEARANCE

ARADUR 435 has a Gardner color limit of approximately 10.
This is acceptable for pigmented primers, protective coatings and many industrial adhesive systems.
The normal appearance should remain a homogeneous liquid without abnormal separation or sediment during appropriate storage.
Further water dilution can make the mixture appear milky. Dedicated technical guidance states that this milky appearance is not necessarily critical in pigmented formulations.
Color and visual appearance should always be interpreted together with viscosity, water content and functional cure behavior.

BENZYL-ALCOHOL-FREE CHARACTER

Published waterborne-hardener selector literature identifies ARADUR 435 as benzyl-alcohol-free.
Benzyl alcohol is used in some amine curing agents as a viscosity reducer or cure modifier, but ARADUR 435 achieves its aqueous processing characteristics without relying on that component.
The absence of benzyl alcohol can be useful where migration, VOC or water-resistance considerations make that auxiliary material undesirable.
The complete formulation should still be reviewed because other resin-side or additive components can introduce volatile or restricted substances.
Formal compliance claims should be supported by current product-specific documentation.

EXCELLENT ADHESION

Excellent adhesion is the principal current product feature associated with ARADUR 435.
The hardener is particularly suitable in adhesive-primer formulations where bonding is required both to the substrate below and the coating above.
Polyamidoamine chemistry provides polar functionality and flexible molecular segments that support interfacial contact and durable bonding.
Low-quality surface preparation can still defeat good hardener chemistry. Dust, oil, rust, weak concrete laitance and curing compounds should be removed before coating.
Adhesion should be tested after full cure and after relevant water, chemical or thermal exposure when long-term durability is important.

ADHESIVE PRIMER PERFORMANCE

ARADUR 435 is especially suitable as an adhesive primer.
An adhesive primer must bond to the original substrate while also creating a surface that the following layer can adhere to reliably.
This dual requirement is important in multilayer flooring, concrete protection and industrial maintenance systems.
The primer should wet the substrate without leaving a weak water-rich or under-cured boundary layer.
Recoat timing should be validated so the next layer is applied when the primer has sufficient integrity but still provides good intercoat adhesion.
Where the primer cures fully before overcoating, cleaning or mechanical preparation may be required depending on the complete system.

WORKING TIME

A critical application point is that working time can be shorter than the formal gel-time range.
In a reference dispersion coating based on ARALDITE PY 33757 and ARADUR 435, the useful working time is limited to approximately one hour.
After this period, gloss and resistance to chemical stresses deteriorate distinctly even if the mixture has not yet become completely solid.
After approximately two hours, the reference dispersion can separate into organic and aqueous phases.
This illustrates why usable pot life in a waterborne epoxy system must be defined by application quality rather than by gelation alone.
Old mixed material should not be restored simply by adding water because chemical advancement and phase instability cannot be reversed by dilution.

PHASE STABILITY DURING POT LIFE

Waterborne epoxy systems combine reactive chemistry with colloidal or emulsion stability.
As cure advances, compatibility between the organic resin phase, aqueous phase and curing-agent phase changes.
The reference ARALDITE PY 33757 / ARADUR 435 dispersion eventually loses stability and separates after prolonged standing.
This behavior is not merely cosmetic because the phase-separated material cannot provide uniform stoichiometry or film properties after application.
The practical pot-life limit should therefore be respected even when mechanical stirring can temporarily redisperse the mixture.

APPLICATIONS

Waterborne primers
Primers are a primary current end use. ARADUR 435 provides excellent adhesion and can form a strong interfacial layer between metal or mineral substrates and subsequent coatings.

Adhesive primers
ARADUR 435 is particularly suited to adhesive-primer formulations where both substrate adhesion and intercoat adhesion are important.

Waterborne coatings
The grade is designed for two-component waterborne epoxy coatings on metallic and mineral substrates.

Waterborne adhesives
Waterborne adhesive is a primary current end use. ARADUR 435 can cure compatible aqueous epoxy adhesive systems where water can leave the bond line.

Metal primers
Prepared metal substrates can use ARADUR 435-based primers where waterborne processing and strong adhesion are desired.

Steel primers
Steel can be coated with compatible waterborne epoxy primer systems after suitable cleaning and surface preparation.

Mineral-substrate primers
Concrete, masonry and related mineral surfaces can use ARADUR 435 primers where substrate strength and moisture are acceptable.

Concrete primers
ARADUR 435 can be used to create adhesion-promoting primer layers on prepared concrete before protective coatings or floor systems.

Concrete sealers
Low- to medium-build sealers can use the grade where a waterborne binder and strong mineral adhesion are required.

Protective concrete coatings
Industrial concrete can be protected against water, oils and selected chemicals using compatible fully cured epoxy formulations.

Industrial maintenance coatings
Waterborne protective coatings for machinery, structures and plant areas can use ARADUR 435 when low conventional solvent content and adhesion are 
important.

Civil-engineering coatings
Historical application positioning includes civil engineering. Concrete primers, protective mineral coatings and multilayer repair systems are relevant areas.

Marine coatings
Historical selector positioning also includes marine coatings. Any marine use should be validated for salt resistance, corrosion protection and drying under realistic humidity.

Anti-corrosion primers
ARADUR 435 can be used in compatible waterborne anti-corrosion primer technology where the pigment package and resin system are properly designed.

Direct-to-metal coatings
DTM systems can be developed where strong adhesion and barrier performance are required in one layer. Finished-system corrosion testing is essential.

Zinc-phosphate primers
Zinc phosphate and related inhibitive pigments can supplement the barrier properties of the cured epoxy binder.

Barrier coatings
Lamellar fillers and extenders can increase the diffusion path for water and oxygen in protective coatings.

Force-dried coatings
ARADUR 435 is especially suitable for force-dried dispersion coatings. Controlled heat and airflow can accelerate water removal and film development.

Low-binder dispersion coatings
Dedicated technical guidance highlights dispersion coatings with relatively low binder content, where adhesion and film formation must remain effective 
despite a high pigment or filler fraction.

Solvent-free coating systems
The hardener itself contains no conventional organic solvent and can support solvent-free formulation concepts when the resin and additives are selected accordingly.

Low-solvent coating systems
ARADUR 435 can also be used in low-solvent systems where a limited amount of auxiliary solvent or coalescent is needed for the total formulation.

Factory-applied coatings
Controlled industrial application can take advantage of force drying, ventilation and standardized film thickness.

Production-line primers
Waterborne epoxy primers can be used in factory operations where ovens or warm-air zones accelerate water removal.

Machinery primers
Machine frames and fabricated equipment can use compatible ARADUR 435 waterborne primers when the substrate is properly prepared.

Equipment coatings
Industrial equipment can use the grade in protective systems where adhesion, low solvent content and chemical resistance are required.

Pipe coatings
Prepared pipes can use compatible waterborne epoxy coatings for atmospheric and selected industrial exposure.

Tank exteriors
Exterior tank surfaces can use waterborne epoxy primers beneath suitable weather-resistant topcoats.

Interior industrial coatings
Low conventional solvent content makes the grade useful in enclosed industrial areas where strong solvent odor is undesirable, provided adequate drying 
ventilation is available.

Warehouse coatings
Structural steel and concrete in warehouses can use compatible waterborne epoxy primers and protective coatings.

Workshop coatings
Workshop walls, floors and equipment can use ARADUR 435 systems where adhesion and cleanability are important.

Floor primers
The grade can be evaluated in floor primers that promote adhesion between prepared concrete and subsequent coating or flooring layers.

Floor sealers
Waterborne sealers can use ARADUR 435 where substrate penetration, adhesion and low organic-solvent content are required.

Repair primers
Concrete or metal repair systems can use ARADUR 435 primer layers before compatible repair mortars or topcoats.

Bonding layers
Waterborne epoxy bonding layers can use ARADUR 435 where water release and interfacial cure have been validated.

Waterborne laminating adhesives
Thin bond lines and porous adherends can permit water loss in compatible adhesive systems.

Paper and porous-substrate bonding
Waterborne epoxy adhesive technology can be considered where the adherend allows sufficient water evaporation and the final bond properties meet 
requirements.

Construction adhesives
Compatible mineral-to-mineral or mineral-to-metal bonding formulations can use ARADUR 435 where aqueous processing is beneficial.

Primer under floor coatings
ARADUR 435 can provide a strong adhesion bridge between concrete and later body coats when recoat timing is controlled.

Primer under protective topcoats
The grade can create an adherent base layer beneath compatible protective finishes.

Pigmented waterborne coatings
The tendency toward milkiness on further water dilution is generally less significant in pigmented systems because the final appearance is dominated by pigments.

High-PVC primers
Low-binder or high-pigment-volume formulations can use ARADUR 435 where sufficient binder continuity and adhesion are maintained.

Maintenance repair coatings
Localized waterborne repair systems can use the hardener where old coating compatibility and surface preparation are verified.

Concrete wall coatings
Vertical mineral surfaces can use ARADUR 435 when rheology is adjusted to prevent sag.

Masonry protection
Prepared masonry can use waterborne epoxy primer or sealer systems where moisture movement is acceptable.

Adhesion-promoting intermediate layers
Multilayer protective systems can use ARADUR 435 as an adhesion-focused layer between unlike coating technologies when compatibility is validated.

Low-emission industrial coatings
The absence of conventional organic solvent in the hardener supports low-emission formulation strategies.

General waterborne epoxy systems
Other applications are possible when resin compatibility, pot life, water release, substrate condition and final performance are validated.

ARALDITE PY 33757 REFERENCE SYSTEM

ARALDITE PY 33757 is an important liquid epoxy-resin reference for ARADUR 435.
The optimum historical mix ratio is approximately 100 parts ARALDITE PY 33757 to 140 parts ARADUR 435 by weight.
This relatively high wet-hardener level reflects the approximately 50% solids commercial form of ARADUR 435.
The system can be formulated into water-based coatings for mineral and metallic substrates.
A critical processing limitation is the practical working time. The reference dispersion should generally be applied within approximately one hour.
After that time, gloss and resistance to chemical stresses decline, and after approximately two hours phase separation can occur.

ARALDITE PZ 33757/67 REFERENCE SYSTEM

ARALDITE PZ 33757/67 is a pre-emulsified epoxy-resin reference system for ARADUR 435.
The optimum historical mix ratio is approximately 100 parts ARALDITE PZ 33757/67 to 95 parts ARADUR 435 by weight.
The substantially lower hardener level compared with PY 33757 demonstrates that one wet-weight ratio cannot be transferred across different epoxy resin forms.
A pre-emulsified resin already contains its own water, solids and emulsion structure, so stoichiometry and film formation must be considered together.
Current resin-specific documentation should be used if the commercial resin formulation or solids level has changed.

MIX-RATIO FLEXIBILITY

Historical technical guidance allows deviations of up to approximately 10% from the optimum reference ratios.
A higher proportion of ARADUR 435 generally increases flexibility and adhesion.
A reduced hardener proportion generally improves chemical resistance.
These effects result from deliberate changes in network stoichiometry and should be treated as formulation tools rather than weighing tolerances.
Any ratio adjustment should be checked for cure completeness, water resistance, gloss, adhesion and chemical resistance.

WHY THE TWO REFERENCE RATIOS DIFFER

ARALDITE PY 33757 and ARALDITE PZ 33757/67 are not the same resin in two package sizes.
They differ in physical form, water content, solids and effective epoxy functionality per unit of commercial product.
The 100:140 and 100:95 ratios therefore reflect different commercial resin bases.
Using the PY 33757 ratio with PZ 33757/67, or the reverse, would create a significant stoichiometric error.
Every waterborne epoxy formulation should therefore identify the exact resin grade before selecting the hardener level.

WATER DILUTION

ARADUR 435 can be further diluted with water when application viscosity requires adjustment.
Additional water may produce a milky appearance. Dedicated technical guidance states that this is not necessarily critical in pigmented formulations.
Milky appearance should be distinguished from irreversible phase separation after excessive pot-life aging.
More water lowers wet viscosity but also lowers wet-film solids and increases drying demand.
Dilution should therefore be controlled and repeatable rather than performed by visual judgment at the job site.

MILKY APPEARANCE ON DILUTION

The milky appearance that can occur after water dilution results from changes in colloidal or emulsion structure.
It does not automatically mean that the hardener has chemically decomposed.
In pigmented coatings, the visual effect is usually masked by the pigment package and may not be performance-critical.
Clear or translucent systems require greater caution because haze can remain visually important.
Stability and final film properties should be checked rather than judging diluted material only by appearance.

FORCE DRYING

ARADUR 435 is particularly suitable for force-dried dispersion coatings.
Moderate heat and controlled airflow can accelerate water removal and help the dispersed resin phase form a continuous film.
Force drying can shorten handling time and improve production throughput.
Temperature should remain within the validated range of the substrate, resin and additives.
Excessively rapid surface drying can create skinning or trap water deeper in the film, so airflow and temperature should be optimized together.

FILM FORMATION

Waterborne epoxy cure requires both chemical crosslinking and physical development of a continuous polymer film.
If water remains trapped or resin domains fail to coalesce properly, the coating can become porous, hazy or weak.
The resin type strongly affects this process. Liquid resin emulsions and water-dilutable liquid resins behave differently.
Temperature, humidity, added water, film thickness and air movement all influence film formation.
A successful formulation must therefore balance cure rate with water evaporation rather than optimizing either process in isolation.

VENTILATION

Ventilation is important even though ARADUR 435 contains no conventional organic solvent.
Air movement removes water vapor from the coating surface and maintains the driving force for drying.
High humidity or stagnant air can slow physical drying significantly.
Excessive airflow can create uneven drying or surface skinning in some formulations.
The required ventilation depends on film thickness, water content and application temperature.

LOW-TEMPERATURE APPLICATION

Low temperature increases viscosity and slows both epoxy-amine reaction and water evaporation.
The final ARADUR 435 system should therefore be qualified at the minimum intended application temperature.
Cold substrates can also fall below the dew point and develop condensation.
Condensation can reduce adhesion regardless of curing-agent quality.
Force drying can help in controlled environments, but field application still requires substrate-temperature and humidity control.

HIGH-HUMIDITY APPLICATION

High atmospheric humidity reduces the rate at which carrier water can evaporate.
This can extend dry time and delay development of water resistance or gloss.
A waterborne hardener does not automatically make the complete coating suitable for wet or condensing surfaces.
Substrate moisture and dew point should be evaluated independently.
Where high humidity is expected, the complete system should be tested under representative conditions.

PIGMENT COMPATIBILITY

ARADUR 435 is well suited to pigmented formulations.
The product's milky appearance after additional water dilution is generally less important in pigmented systems.
Pigment surfaces can nevertheless interact with amine functionality, dispersants and waterborne rheology modifiers.
Titanium dioxide, iron oxides, zinc phosphate, barytes, talc, mica and silica can be evaluated depending on application.
The final two-component coating should be checked for viscosity, stability and pot life after all pigments and fillers are present.

ANTI-CORROSIVE PIGMENTS

Waterborne anti-corrosion primers can combine ARADUR 435 with compatible inhibitive pigments.
Zinc phosphate and related pigments can supplement the barrier protection of the epoxy binder.
Lamellar fillers can increase the diffusion path for water and oxygen.
Pigment selection should also consider waterborne stability and soluble-salt content.
The finished formulation should be validated through corrosion testing rather than assuming performance from the hardener alone.

RHEOLOGY CONTROL

ARADUR 435 is moderately viscous, but final coating rheology depends on resin, water, pigment and additives.
Vertical primers need enough low-shear structure to prevent sag and settlement.
Spray or roller application requires sufficient shear thinning for good transfer and leveling.
Associative thickeners, cellulose derivatives, clays or other waterborne rheology technologies can be used where compatible.
Rheology should be checked through pot life because reactive advancement and phase changes can alter viscosity.

DEFOAMING AND AIR RELEASE

Waterborne mixing can introduce foam and entrained air.
Bubbles can create pinholes, reduce barrier performance and interfere with adhesion.
Suitable defoamers can improve air release, but excessive dosage can create craters or reduce intercoat adhesion.
Porous concrete can also outgas into a wet primer.
Controlled mixing, suitable application timing and appropriate defoamer selection should therefore be validated together.

SURFACE PREPARATION

Surface preparation is essential to the adhesion advantage of ARADUR 435.
Steel should be free from grease, soluble salts, rust and loose scale.
Concrete should be sound and free from weak laitance, dust, curing compounds and oil.
Porous mineral surfaces may require controlled primer application so the binder penetrates without being starved from the surface.
Good curing-agent chemistry cannot compensate for a contaminated or mechanically weak substrate.

INTERCOAT ADHESION

ARADUR 435 is particularly useful where adhesion to a following coating is important.
The next layer should be applied within a validated recoat window whenever possible.
If the primer cures completely, cleaning or mechanical preparation may be needed depending on the next coating chemistry.
Surface contamination, amine-derived deposits and dirt can interfere with intercoat bonding.
A multilayer system should therefore be evaluated as a complete sequence rather than testing each layer separately.

CHEMICAL RESISTANCE

Chemical resistance depends on the resin, hardener ratio, cure completeness and film structure.
Historical reference guidance notes that reducing the hardener proportion within the allowed range can improve chemical resistance.
Aged mixed material should not be applied because chemical-stress resistance deteriorates as the dispersion exceeds its useful working time.
Testing should use the actual chemical, concentration, temperature and exposure duration expected in service.
Continuous immersion is more demanding than occasional splash and should be qualified separately.

FLEXIBILITY

Historical reference guidance states that increasing the hardener proportion within the allowed range can improve flexibility.
Polyamidoamine molecular structure already tends to provide more flexibility than highly rigid low-molecular-weight amine networks.
Flexibility can help a coating tolerate impact, vibration and substrate movement.
Excessive hardener can reduce chemical resistance or water resistance, so the final ratio should reflect service requirements.
Impact, bend or other mechanical tests can be used to quantify the formulation balance.

ADHESION

A higher hardener proportion within the allowed reference range can increase adhesion.
This can be useful on difficult mineral surfaces or in primer applications where intercoat bonding is critical.
The effect should not be used to compensate for poor surface preparation.
Adhesion should be evaluated after full cure and after exposure to water or chemicals when relevant.
Pull-off or cross-cut methods can be selected according to the substrate and coating thickness.

POT-LIFE QUALITY LOSS

The ARADUR 435 reference system demonstrates that pot-life failure can occur before dramatic gelation.
After approximately one hour in the PY 33757 dispersion, gloss and chemical-stress resistance begin to deteriorate.
After roughly two hours, organic and aqueous phase separation may become visible.
The coating should therefore be applied inside the validated working period even when it still appears stirrable.
This principle is especially important for waterborne epoxies because appearance in the mixing vessel can be misleading.

QUALITY CONTROL

Important quality-control parameters include Gardner color, amine value, water or solids content, viscosity, density and functional cure behavior.
Color should remain approximately ≤10, amine value approximately 160-200 mg KOH/g and viscosity approximately 13,000-23,000 mPa·s at 25°C according to published data.
Water content of approximately 49-51% confirms the intended aqueous concentration.
A standardized resin pot-life or cure test can provide an additional functional check where production consistency is critical.
Current product-specific specifications should govern acceptance if newer values differ from historical dedicated data.

WHY SOLIDS CONTENT MATTERS

Solids determine how much active curing-agent material is delivered per unit wet weight.
If water content rises beyond specification, less reactive material enters the formulation at the same weighed quantity.
This changes stoichiometry and increases drying demand.
If solids rise, viscosity and reactive concentration can increase.
Consistent concentration is therefore necessary for repeatable cure and coating performance.

WHY AHEW MATTERS

AHEW connects hardener mass directly to reactive amine hydrogen.
ARADUR 435 has an approximate AHEW of 250 g/eq as supplied.
The value should be combined with the actual resin EEW when theoretical stoichiometry is calculated.
Using the AHEW of another waterborne hardener can create a major ratio error.
Where a validated resin-specific ratio is available, that formulation should be the primary practical reference.

WHY WORKING TIME MATTERS

ARADUR 435 illustrates why working time should be defined through performance rather than only through gelation.
A mixed dispersion can remain fluid but already produce reduced gloss or lower chemical resistance.
If phase separation begins, application quality becomes even less reliable.
Production procedures should therefore specify a maximum elapsed time from mixing.
Leftover material beyond that window should be discarded according to appropriate waste procedures rather than reconditioned for application.

TDS, SDS AND COA

The current Technical Data Sheet or official product information should be used for present specifications, application guidance, storage conditions and mix ratios.
The Safety Data Sheet governs formal composition disclosure, hazard classification, first aid, transport, handling and disposal.
The Certificate of Analysis provides batch-specific controlled values where supplied.
Historical dedicated technical data are valuable for the PY 33757 and PZ 33757/67 mix ratios, water-dilution behavior, working-time limitation and storage guidance.
Where current product information and older dedicated data differ, current product-specific documentation should take precedence.

SAFETY AND HANDLING

ARADUR 435 is a reactive amine-containing curing agent and should be handled according to the current SDS.
The waterborne, organic-solvent-free commercial form reduces conventional solvent flammability and vapor exposure but does not eliminate hazards associated with reactive amine chemistry.
Chemical-resistant gloves, eye protection and suitable protective clothing should be selected through workplace risk assessment.
Ventilation remains important during mixing and application, especially where spraying creates aerosol.
The complete coating or adhesive can contain additional ingredients with their own hazards, so PPE should reflect the full formulation.

FIRST AID

After skin contact, contaminated skin should be washed promptly according to current SDS guidance and contaminated clothing should be removed where appropriate.
If product enters the eyes, immediate prolonged rinsing with clean water should begin and medical attention should be obtained according to SDS instructions.
If mist or aerosol is inhaled and symptoms occur, the affected person should be moved to fresh air and appropriate medical advice obtained.
After accidental ingestion, follow the current SDS and professional medical guidance rather than generic amine advice.

SPILL MANAGEMENT

Spilled ARADUR 435 can create a slippery surface because it is an aqueous polymeric liquid.
The release should be contained promptly while personnel use the PPE specified in the current SDS.
Suitable absorbent or pumping methods can be used depending on spill size.
Uncontrolled release to drains, soil or surface water should be prevented.
Recovered material and contaminated absorbent should be disposed of according to applicable local requirements.

FIRE RESPONSE

ARADUR 435 has a very high typical flash point and substantial water content, which reduces conventional flammability relative to solvent-borne hardeners.
The organic polyamidoamine-adduct fraction can nevertheless burn or decompose under severe heating.
Published technical information identifies carbon monoxide, carbon dioxide, nitrogen oxides and other toxic gases and vapors as possible decomposition products.
Fire response, extinguishing media and firefighter protection should follow the current product-specific SDS and site emergency plan.

STORAGE

ARADUR 435 should be stored in a dry place, preferably in the sealed original container.
Historical dedicated guidance gives a storage range of approximately 2-40°C and states that temperature should not fall below 0°C.
The product should be protected from direct sunlight.
Containers should remain tightly closed to prevent contamination and uncontrolled water loss.
Historical shelf life is listed as at least approximately three years under the stated storage conditions, subject to the expiry date on the original container.
Current package and product documentation should govern actual shelf-life decisions.

REGULATORY CONSIDERATIONS

ARADUR 435 is a proprietary commercial waterborne polyamidoamine-adduct mixture.
Current product positioning includes organic-solvents-free and solvent-free labeling claims, while published selector literature also identifies the grade as benzyl-alcohol-free.
These claims should be supported by current product-specific documentation when used formally.
Generic suitability for coatings, primers or adhesives does not establish approval for food contact, potable water, medical devices or other specialized regulated uses.
Regional chemical-inventory and compliance status should be checked using current documentation for the intended market.

ENVIRONMENTAL CONSIDERATIONS

Waterborne delivery can reduce conventional organic-solvent emissions during coating manufacture and application.
Uncured amine-containing material should nevertheless not be discharged directly into soil, drains or surface water.
Cleaning water can contain hardener, resin, pigment and additives and should be managed as process waste under applicable rules.
Leftover mixed resin and hardener should be allowed or managed to cure only under controlled conditions because reaction and phase separation can occur.
Fully cured epoxy has different mobility and reactivity from uncured components, but disposal requirements remain jurisdiction-specific.

COMMON FORMULATION PROBLEMS

Working time exceeded
A mixed dispersion can remain fluid after its optimum working period while gloss and chemical resistance have already deteriorated. Establish and enforce a maximum elapsed application time.

Phase separation after standing
The PY 33757 reference dispersion can separate into organic and aqueous phases after prolonged standing. Material that has reached this state should not be treated as fresh coating.

Milky appearance after water dilution
Further water dilution can produce a milky appearance. This is not necessarily critical in pigmented formulations, but clear systems require additional visual evaluation.

Poor gloss
Late-pot-life application, incomplete film formation, high humidity or excessive dilution can reduce gloss. Apply fresh material within the validated working window.

Poor chemical resistance
Late application, off-ratio cure or insufficient final cure can reduce chemical resistance. Use the validated ratio and allow adequate cure before exposure.

Poor adhesion
Oil, dust, salts, rust, weak concrete laitance or curing compounds can create a weak boundary layer. Correct surface preparation before reformulating.

Intercoat adhesion failure
Overcure, contamination or an unsuitable recoat interval can reduce bonding to the following layer. Validate the complete coating sequence.

Slow drying
High humidity, low temperature, poor ventilation or excessive added water can slow physical drying. Improve airflow and control dilution.

Soft film
Incorrect stoichiometry, retained water or incomplete cure can leave the film soft. Verify ratio, drying and cure conditions.

Foaming
High-shear mixing or incompatible additives can introduce persistent foam. Optimize agitation and defoamer selection.

Pinholes
Entrained air or porous-substrate outgassing can create pinholes. Prime porous surfaces and improve air release.

Sagging
Excess water or insufficient rheology can reduce vertical hold. Adjust dilution, wet-film thickness and rheology.

Poor corrosion resistance
Low film thickness, pinholes, poor steel preparation or an unsuitable pigment package can reduce protection. Evaluate the complete primer system.

Flash rust on steel
Waterborne systems can promote early corrosion on reactive steel if drying is slow or inhibition is inadequate. Optimize surface preparation, pigments and drying conditions.

High viscosity
Low product temperature, excessive pigment loading or reactive advancement can raise viscosity. Confirm temperature and pot-life age before adding water.

Low viscosity
Unexpectedly low incoming viscosity can indicate excess water or contamination. Check water content, density and amine value.

FREQUENTLY ASKED QUESTIONS

What is ARADUR 435?
ARADUR 435 is a waterborne polyamidoamine-adduct epoxy curing agent used mainly in primers, waterborne coatings and waterborne adhesives.

What is the solids content?
Approximately 49-51% by weight.

How much water does ARADUR 435 contain?
Dedicated technical data give approximately 49-51% water.

What is the viscosity?
Approximately 13,000-23,000 mPa·s at 25°C.

What is the amine value?
Approximately 160-200 mg KOH/g.

What is the active hydrogen equivalent weight?
Approximately 250 g/eq.

What is the density?
Approximately 1.04 g/cm³ at 20°C.

What is the flash point?
Typical dedicated technical data give a minimum of approximately 200°C by Pensky-Martens closed-cup testing.

What is the Gardner color?
Approximately ≤10.

Is ARADUR 435 waterborne?
Yes. It is a polyamidoamine adduct supplied in water.

Does ARADUR 435 contain conventional organic solvent?
Current product positioning identifies the commercial hardener as organic-solvents-free / solvent-free.

Is ARADUR 435 benzyl-alcohol-free?
Published selector literature identifies ARADUR 435 as benzyl-alcohol-free.

What are the main applications?
Primers, waterborne coatings and waterborne adhesives are the primary current end uses.

Which substrates are suitable?
Metal and mineral substrates are the primary current compatibility categories.

Why is ARADUR 435 useful as a primer?
It provides excellent adhesion to the substrate and can also promote adhesion of the following coating.

What is the reference ratio with ARALDITE PY 33757?
Approximately 100 parts resin to 140 parts ARADUR 435 by weight.

What is the reference ratio with ARALDITE PZ 33757/67?
Approximately 100 parts resin to 95 parts ARADUR 435 by weight.

Can the reference ratio be adjusted?
Yes. Historical dedicated guidance allows deviations of up to approximately ±10%, with more hardener tending to increase flexibility and adhesion and less hardener tending to improve chemical resistance.

What is the practical working time with ARALDITE PY 33757?
The reference dispersion should generally be used within approximately one hour because gloss and chemical resistance decline afterward.

What happens after about two hours in the PY 33757 reference dispersion?
Phase separation between organic and aqueous portions can occur.

Can ARADUR 435 be diluted with water?
Yes, but additional water can produce a milky appearance and increases drying demand.

Is the milky appearance always a problem?
No. Dedicated technical guidance states that it is not necessarily critical in pigmented formulations.

Is ARADUR 435 suitable for force drying?
Yes. It is especially suitable for solvent-free or low-solvent, force-dried dispersion coatings with relatively low binder content.

Does ARADUR 435 have one CAS number?
No single CAS number should be assigned to the complete commercial mixture without confirmation from the current SDS.

How should ARADUR 435 be stored?
Store dry in the sealed original container at approximately 2-40°C, protect from direct sunlight and avoid freezing.

What is the historical shelf life?
At least approximately three years under the stated storage conditions, subject to the expiry date on the original container.

What documents should be checked before use?
Use the current product TDS, SDS and batch-specific quality documentation where available.

FINAL TECHNICAL SUMMARY

ARADUR 435 is a waterborne polyamidoamine-adduct epoxy curing agent developed for primers, waterborne coatings and waterborne adhesive systems.
The commercial product is supplied at approximately 49-51% solids in water, with dedicated technical data also listing approximately 49-51% water content.
Published properties include approximately 13,000-23,000 mPa·s viscosity at 25°C, 160-200 mg KOH/g amine value, approximately 250 g/eq active-hydrogen equivalent weight, Gardner color ≤10 and density around 1.04 g/cm³ at 20°C.
The typical flash point is at least approximately 200°C, consistent with the aqueous organic-solvent-free delivery form.

Excellent adhesion is the principal current product feature, and ARADUR 435 is particularly useful as an adhesive primer because it can bond strongly to the substrate and also to the following coating layer.
Current product positioning includes metal and mineral substrates and identifies primers, waterborne coatings and waterborne adhesives as principal end uses.
Published selector literature identifies the grade as benzyl-alcohol-free.

ARALDITE PY 33757 is an important liquid-resin reference system with an optimum historical ratio of approximately 100 parts resin to 140 parts ARADUR 435 by weight.
ARALDITE PZ 33757/67 is an important emulsion reference system with an optimum ratio of approximately 100 parts resin to 95 parts ARADUR 435 by weight.
Historical guidance allows approximately ±10% adjustment from the optimum ratio. More hardener generally increases flexibility and adhesion, while less hardener generally improves chemical resistance.

The PY 33757 reference dispersion demonstrates that practical working time can be shorter than formal gel time. Application should generally be completed within approximately one hour.
After the useful working period, gloss and chemical-stress resistance deteriorate, and after approximately two hours the reference mixture can separate into organic and aqueous phases.
Further water dilution can create a milky appearance. This is not necessarily critical in pigmented formulations, but excessive dilution increases drying demand and should be controlled.

ARADUR 435 is particularly suitable for solvent-free or low-solvent, force-dried dispersion coatings with relatively low binder content.
Waterborne film formation requires both chemical cure and physical water removal, so temperature, humidity, ventilation and film thickness are important processing variables.
Surface preparation remains essential. Steel should be clean and appropriately prepared, while mineral substrates should be sound and free from weak laitance, dust, oil and curing compounds.

Quality control should focus on color, amine value, water or solids content, viscosity, density and functional cure behavior.
ARADUR 435 is a proprietary commercial mixture and should not be assigned an invented single molecular formula, molecular weight, CAS number or EC number.
Historical storage guidance specifies approximately 2-40°C, no storage below 0°C, protection from direct sunlight and at least approximately three years shelf life under the stated conditions, subject to the original-container expiry date.
For ARADUR 435 technical specifications, application guidance, TDS, SDS, COA and formulation information, contact Ataman Chemicals with the intended epoxy resin, substrate, application method, dilution level and required adhesion or protective performance.

Ataman Chemicals
Phone: +90 216 577 10 10
Email: info@atamankimya.com