BYK-358 N

PRODUCT IDENTITY

BYK-358 N is a commercial mixture consisting of a polyacrylate dissolved in alkylbenzene solvent. Its trade designation identifies the supplied polymer solution, including the carrier and the resulting handling characteristics. A generic polyacrylate resin or an aromatic solvent alone does not represent the complete grade.
CAS Number: No single CAS number is specified here for the complete commercial mixture. The disclosed aromatic solvent component is identified as solvent naphtha, petroleum, light aromatic, CAS 64742-95-6. That number belongs to the component and should not be used as the identity of the entire additive.
EC Number: No single European Community number is assigned here to the formulated product. Component inventory numbers and the identity of the commercial mixture should remain separate in technical records.
Molecular Formula: Not applicable as one fixed formula for the supplied polymer solution. Both the polymeric component and the hydrocarbon solvent involve molecular distributions rather than one discrete small molecule.
Molecular Weight: Not applicable as one exact molecular weight for the complete grade. A meaningful polymer molecular-weight description would require a defined distribution and analytical method, neither of which is established here.
The product belongs to the surface additive category and is documented as a leveling and anti-cratering additive. Its polyacrylate chemistry should not be confused with polyacrylic acid, an acrylic monomer, or a complete acrylic coating binder. A low-dose surface additive and the principal film-forming resin have different formulation roles.
Grade identity matters when comparing supplied forms. A solvent-free version of a similar polymer may require a different addition mass and a different incorporation procedure. A change in carrier also changes the solvent balance of the formulation, so nominal polymer similarity does not justify a direct one-for-one substitution by mass.

SYNONYMS

BYK-358 N, BYK 358 N, BYK-358N, BYK 358N, BYK358N, BYK-358 N surface additive, BYK-358 N polyacrylate additive, BYK-358 N acrylic surface additive, BYK-358 N leveling additive, BYK-358 N levelling additive, BYK-358 N anti-cratering additive, BYK-358 N crater-control additive, BYK-358 N flow and leveling agent, BYK-358 N coating surface modifier, BYK-358 N polyacrylate solution, BYK-358 N alkylbenzene solution, BYK-358 N solvent-borne coating additive, BYK-358 N clear-coat leveling additive, BYK-358 N pigmented coating additive, BYK-358 N gloss-supporting additive, BYK-358 N semi-polar system additive, BYK-358 N polar system additive

DESCRIPTION AND COMPOSITION

The supplied form is a solution of a polyacrylate in alkylbenzenes. The typical nonvolatile matter is 52% under a test condition of 10 minutes at 150°C. This value describes the residue obtained by the stated method; it should not be treated as a general analytical purity statement or as a complete description of the polymer architecture.
The solvent fraction is significant to both formulation and handling. The safety disclosure places the aromatic solvent component in a range of at least 30% and less than 50% by mass. That is a hazard-reporting interval rather than an exact batch assay. It is consistent with a solvent-containing grade and should not be replaced by an unsupported statement that the additive is entirely polymeric active material.
Polyacrylates used as surface additives are selected for their interaction with the liquid coating and its interfaces. The commercial description does not specify the monomer sequence, exact side-chain distribution, or one molecular structure. A technical profile should therefore discuss the documented function and measurable supplied properties without inventing a detailed structural formula.
The alkylbenzene carrier contributes to ease of incorporation into compatible organic formulations. It also becomes part of the formulation's solvent package, influencing mass balance and potentially the evaporation sequence. A carrier that is convenient for handling is not automatically neutral with respect to every resin, application process, or emissions requirement.
BYK-358 N is not a pigment dispersant, curing agent, reactive diluent, or bulk rheology modifier by virtue of its leveling function. It may influence the visual outcome of a coating, but it does not replace the ingredients responsible for pigment stabilization, cure chemistry, sag control, or film formation. Those functions should be evaluated separately when a formulation problem has more than one cause.

TYPICAL PHYSICAL AND CHEMICAL PROPERTIES

The typical density is 0.95 g/mL at 20°C, equivalent to approximately 0.95 kg/L. This supports approximate volume conversions and equipment planning. For accurate low-level addition, weighing avoids uncertainty from temperature, transfer retention, and an uncalibrated volumetric measure.
The typical nonvolatile matter is 52% after 10 minutes at 150°C. Test temperature, duration, sample mass, and geometry influence residue measurements and should be controlled in quality work. A different drying method may produce a different result without demonstrating that the product composition has changed.
The flash point is 47°C. The safety information identifies an Abel-Pensky method for this value. It is a flammable liquid supplied with an aromatic solvent carrier, so storage and transfer require ignition control and ventilation. Flash point is not a recommended processing temperature or a threshold below which ignition risk disappears.
The product is described as a light brown liquid with a characteristic odor. These observations should be assessed on a representative sample in suitable lighting and conditions. A change in odor alone is not a quantitative analysis, while unusual sediment, marked discoloration, or evidence of contamination should prompt investigation.
The safety description reports water immiscibility. BYK-358 N should not be assumed suitable for direct incorporation into an aqueous paint merely because some other polyacrylate additives are used in waterborne systems. Carrier compatibility and polymer behavior in the complete formulation must be considered together.
A kinematic viscosity of approximately 117 mm²/s at 40°C is reported in the safety information. This is a condition-specific value, not a guaranteed viscosity limit for all batches or a prediction of the viscosity of a paint containing the additive. Dynamic and kinematic viscosity also are different quantities and should not be interchanged without the relevant density and conditions.
The grade is described qualitatively as thermally stable for its intended use. No universal maximum service temperature, continuous exposure rating, or exact thermal decomposition limit is assigned here. The temperature behavior of a cured coating or resin must be assessed in that complete system rather than inferred from the additive alone.
Typical properties support product understanding but do not constitute a complete release specification. Any contractual density, solids, viscosity, appearance, or performance limits require an agreed method and acceptance range. Copying one typical number into a purchasing specification without that context can create an unsuitable acceptance criterion.

LEVELING AND SURFACE EFFECTS

Leveling is the movement of a freshly applied liquid toward a more uniform surface before evaporation, viscosity rise, or cure prevents further flow. It depends on surface forces, viscosity, film thickness, application texture, and the time available for movement. A leveling additive acts within this balance rather than removing every physical limitation on flow.
Local surface tension differences can drive unwanted movement and visible nonuniformity. A polyacrylate surface additive can help reduce the effect of relatively small differences while producing only a limited change in the overall surface tension. This is consistent with the intended character of BYK-358 N and explains why it should not be treated as a universal strong substrate-wetting agent.
Cratering can develop when a local region of different interfacial behavior causes the film to withdraw or become uneven. BYK-358 N is used to improve resistance to such defects in suitable formulations. The effect does not make contaminated substrates, dirty compressed air, incompatible cleaning residues, or uncontrolled overspray acceptable production conditions.
The product can support gloss and alter the surface texture described in technical language as a long-wave effect. These observations should be related to the intended appearance standard. High gloss, low short-scale texture, and low long-scale waviness are related but distinct measurements, and a single gloss reading does not describe the entire surface profile.
The grade is positioned for clarity and low haze in compatible semi-polar to polar systems. This does not establish universal compatibility with every resin and solvent combination. A clear wet blend may become less compatible as solvents evaporate or the resin cures, so the final film must be included in evaluation.
Recoatability and intercoat adhesion are important design considerations for this additive type. The documented positioning is to improve leveling without negatively influencing those properties. Confirm the outcome in the actual layer sequence, preparation method, and recoat interval rather than treating it as an unlimited guarantee for every substrate and topcoat.

DETAILED APPLICATIONS

Solvent-borne coating systems
BYK-358 N is used in solvent-borne coatings to improve leveling and reduce cratering. Its carrier is compatible with the organic formulation concept, but the actual balance of resin polarity and solvent composition remains important. The most useful starting point is a known coating with a defined appearance issue and a controlled application procedure.
Evaluate the coating at its intended application viscosity, film thickness, and drying conditions. A formulation may show an attractive wet surface yet develop texture as the solvent balance changes. Comparing the dried film with the control is therefore essential, particularly when the additive's carrier changes the evaporation profile of a low-solvent or highly concentrated coating.
In industrial finishing, improved leveling is valuable when it contributes to a consistent accepted surface rather than merely a favorable laboratory drawdown. Assess the intended substrate, transfer method, and production timing. The additive does not replace suitable surface cleaning, stable atomization, correct film build, or a solvent package designed for the process.

Clear coats and transparent finishes
Clear coats make compatibility problems especially visible because turbidity, haze, and localized defects are not concealed by pigment. BYK-358 N is positioned for use where a compatible polyacrylate surface treatment is needed without unwanted cloudiness. Qualification should include the liquid blend, the drying film, and the fully developed finish.
Assess clarity against appropriate references and measure gloss or haze where required. Film thickness, substrate color, and curing conditions can affect the observed result. A transparent drawdown over one background is useful but may not reveal an issue that becomes evident on a darker substrate or at a greater film build.
For decorative clear finishes on suitable wood, metal, or other substrates, the substrate and complete coating chemistry determine the test requirements. Do not infer universal adhesion or durability from a clear appearance. Where later coating, polishing, bonding, or repair is planned, include those operations in the qualification.

Pigmented topcoats
In pigmented systems, BYK-358 N can be evaluated for surface smoothness, crater resistance, gloss, and the absence of additive-related haze. These properties influence the visible quality of a topcoat, but pigment dispersion and surface leveling are different mechanisms. An improvement in appearance should not be described automatically as improved pigment stabilization.
Compare color, gloss, texture, and any visible defects under consistent lighting. Some apparent color changes arise from differences in surface texture or gloss rather than a change in pigment concentration. Measurements and visual assessment should be selected to distinguish these effects when the finish has a tight color standard.
Use the actual pigment and extender package. A result in one shade may not represent a formulation containing a different pigment treatment, filler level, or dispersant balance. Representative testing across commercial variants helps establish whether the selected dose is robust or whether a particular shade requires separate assessment.

Coatings based on a nominally solvent-free matrix
The product may be evaluated in suitable solvent-free host systems, but its own alkylbenzene content enters that system with the addition. This is an important distinction between the application category and the supplied grade. A formulation cannot retain an absolute no-added-solvent claim simply by describing a solvent-containing additive as a minor component.
In such a formulation, assess the added volatile fraction, any change in application viscosity, and the route by which solvent leaves the material. Thick films and rapidly curing systems can retain solvent differently from thin, slowly drying coatings. Examine the finished surface and relevant cured properties rather than assuming the carrier evaporates completely under all conditions.
Where the solvent contribution is unacceptable, a different supplied form may be more appropriate. That decision requires comparison of effective polymer level, incorporation, compatibility, and the surrounding formulation. Removing carrier solvent from a calculation does not establish that the alternative will produce an identical application result.

Ambient-curing epoxy systems
BYK-358 N is recommended for evaluation in ambient-curing resin systems such as epoxy formulations. It can support leveling and crater control where the resin mixture remains mobile long enough for surface adjustment. The actual response depends on the epoxy resin, curing agent, fillers, application thickness, and working time.
For two-component systems, identify the component in which the additive will be stored and verify its compatibility over the intended period. Then test the mixed formulation at the specified component ratio. The additive should not be treated as an epoxy-reactive equivalent or used as a reason to change the resin-to-hardener ratio without a justified formulation basis.
Assessment should include working time, surface appearance, cure development, and properties relevant to the finished use. A smooth film is insufficient if the carrier produces retained solvent, affects the cured surface, or interferes with later coating. Where a coating is applied at greater thickness, examine the section and the surface separately to distinguish air, solvent, and leveling defects.

Ambient-curing unsaturated polyester systems
Unsaturated polyester resins are another documented ambient-curing application class. BYK-358 N can be evaluated to improve surface flow and resistance to cratering in compatible formulations. The additive's modest effect on surface tension should be understood alongside resin viscosity, reactive diluent, initiator package, and the time available before gelation.
Add and distribute the product through a controlled sequence appropriate to the resin system. Confirm the chosen procedure before introducing reactive ingredients where practical. A post-addition option does not remove the need to respect the safe handling and mixing requirements of the complete curing system.
Measure surface appearance together with gel behavior, cure, and the relevant finished properties. The additive is not a catalyst, inhibitor, shrink-control agent, or release agent. If an appearance improvement accompanies a change in another property, establish the cause through comparative testing rather than assigning multiple undocumented functions to the product.

Spray-mist and dust acceptance in resin systems
The ambient-curing application description includes improved acceptance of spray mist and dust. In practical evaluation, this concerns the way a still-mobile surface responds to small deposited material or differences in local surface conditions. It is not an authorization to neglect cleanliness or a guarantee that all contamination will disappear.
Use a defined test where this property matters and compare the resulting finish after cure. The condition of the deposited material, the age of the receiving film, and the surface's remaining mobility can change the result. A fresh liquid film and a film approaching gelation should not be expected to respond identically.
Keep chemical control and environmental control coordinated. Filtered air, maintained spray equipment, clean substrates, and controlled handling remain important. If a defect occurs only in one booth or process area, investigate that environment rather than assuming that the formulation needs an unrestricted increase in leveling additive.

Multilayer and repair coating sequences
BYK-358 N can be evaluated where leveling must be achieved while maintaining acceptable recoatability and intercoat adhesion. The test should reproduce the actual lower coat, topcoat, preparation, and time between layers. A favorable result in one immediate overcoat test does not establish performance after extended aging or under every repair procedure.
Assess the visual appearance and the relevant adhesion or exposure properties of the complete layer stack. Surface contamination, undercure, excessive cure, and cleaning practice can influence the result independently of the additive. The evaluation should make these conditions reproducible before drawing a conclusion about the formulation.
Where a coating is later bonded, printed, or otherwise treated, include that operation if it is part of the product requirement. A leveling additive's modest surface-tension effect does not eliminate all possible interfacial consequences. Finished-system testing provides a more meaningful qualification than a general claim about compatibility.

Post-addition and batch adjustment
The product can be incorporated at any stage of production, including post-addition. This flexibility can be useful in a controlled adjustment of a coating or resin, provided that the batch can be mixed uniformly and the final addition remains within the qualified formulation. It does not mean that an additive can correct every defect after application.
Before treating a full batch, prepare a representative laboratory comparison at several relevant levels. Include the additive already present and account for the extra solvent. Confirm appearance, drying or cure, and any critical later operation before adopting the correction.
If a defect is caused by contamination, solvent imbalance, inadequate atomization, or premature gelation, identify and correct that cause. A successful post-addition procedure should be recorded as a reproducible process rather than used as an informal substitute for stable raw materials and production control.

DOSAGE AND CALCULATION BASIS

For coatings, the recommended starting range is 0.1–1% additive as supplied, based on the total formulation. For ambient-curing plastic or resin systems, the documented starting range is 0.1–0.5% as supplied on the total formulation. These recommendations use the complete solution, not only the polymer residue.
For a 100 kg coating formulation, 0.1–1% corresponds to 0.10–1.00 kg of BYK-358 N. For a 100 kg ambient-curing resin formulation, 0.1–0.5% corresponds to 0.10–0.50 kg. The optimum within the relevant range is established by application trials rather than selected solely from the type of resin.
At the typical 52% nonvolatile figure, a 0.50 kg addition contributes approximately 0.26 kg of nonvolatile material and 0.24 kg of volatile fraction. In a 100 kg total formulation, that corresponds nominally to 0.26% nonvolatile contribution and 0.24% volatile contribution. This is a formulation estimate using typical data, not a batch-specific composition analysis.
On the same nominal basis, the coating range of 0.1–1% corresponds to approximately 0.052–0.52% nonvolatile contribution. The ambient-curing range corresponds to approximately 0.052–0.26%. These conversions help compare supplied forms but do not replace the as-supplied recommendation or establish functional equivalence between different additives.
At 0.95 kg/L, 0.50 kg occupies approximately 0.53 L at 20°C. Use this only as a planning estimate unless a volumetric dosing method is calibrated. Small quantities retained in a transfer vessel or dosing line can represent a meaningful fraction of a low-level addition.
Define whether the additive is included within the stated batch total or added to a completed base batch. Use one convention consistently, and document the basis for any polymer-equivalent comparison. Increasing the product level also increases its carrier contribution, so an observed improvement should be interpreted with that change in mind.

INCORPORATION AND FORMULATION PRACTICE

BYK-358 N can be incorporated during any stage of production, including post-addition. Select a stage that provides uniform distribution without disrupting the resin, pigment dispersion, or cure sequence. The technical instruction does not impose the specialized high-shear requirement of an unrelated defoamer, but adequate mixing is still essential.
Add the measured product into a moving, compatible liquid phase rather than leaving a concentrated portion on an unmixed surface. Match addition rate and mixing time to batch viscosity and equipment. A method that works in a small laboratory vessel may need adjustment when the production vessel has a different circulation pattern.
Evaluate any proposed predilution in a compatible solvent before using it routinely. A solvent blend can change polymer compatibility and the local composition during addition. Water is not a default dilution medium for this water-immiscible organic solution, and an improvised dilution may create turbidity or unstable distribution.
For reactive systems, arrange the sequence around the safe handling requirements of all components. Complete initial mixing and compatibility checks before introducing the cure package where that is practical and consistent with the qualified process. Avoid excessive mixing time after activation if it consumes the available working period or generates unnecessary heat.
Check the final formulation after a representative conditioning period and at the intended application viscosity. Uniform bulk appearance is useful, but surface performance is determined during film formation. A drawdown or application test remains necessary after a change in dose, solvent, mixing sequence, or raw material.
Do not assume that a product addition can recover leveling once the coating has set or the resin has gelled. The useful action occurs while the material retains mobility. A process that removes this flow window too quickly may require adjustment of drying or cure conditions rather than more additive.

COMPATIBILITY AND INTERACTIONS

The grade is intended for semi-polar to polar systems. Resin polarity, solvent quality, pigment treatments, and other additives influence the degree of compatibility. A broad category such as acrylic, epoxy, or polyester is not enough to predict the exact result without considering the specific formulation.
Compatibility can change during evaporation and cure. Solvents may leave at different rates, and a reactive resin may develop a different environment as molecular weight rises. Test the dried or cured film, not only the initial liquid blend. Haze or surface defects can appear late even when incorporation initially seems straightforward.
Other surface additives can modify the response. Wetting agents, slip additives, defoamers, and rheology modifiers may affect the same film through different mechanisms. Evaluate combinations in the actual proportions rather than assuming that two individually successful additives will always work well together.
The product's minor surface-tension reduction should not be confused with universal wetting of low-energy substrates. If the substrate is difficult to wet, assess cleaning, surface treatment, and the appropriate wetting strategy. A leveling improvement on an already wetted panel does not establish that the additive can overcome a severe substrate-energy mismatch.
The solvent carrier must be considered in low-VOC, high-solids, thick-film, and rapid-cure systems. Even a small volatile addition can matter when the formulation has a strict emissions limit or limited opportunity for solvent escape. Use a mass balance and a realistic process test to determine whether the contribution is acceptable.
Acids and strong oxidizing agents are identified as incompatible storage contacts. This information does not by itself predict the behavior of every resin containing acidic functional groups. Direct contact with a concentrated incompatible chemical and controlled use in a formulated resin are different situations requiring their own assessment.

LABORATORY EVALUATION

Begin with a clear description of the defect: poor leveling, craters, haze, short-scale texture, long-scale waviness, or an issue after recoating. Several defects may appear similar at first glance but respond to different formulation changes. Use suitable lighting, reference panels, and controlled application conditions to establish the baseline.
Prepare a control and a dosage series within the range relevant to the application. Keep resin, solvent balance, pigment package, application viscosity, and conditioning temperature as consistent as practical. Record the solvent introduced with the additive so that its contribution is visible in the comparison.
Application should reproduce the intended substrate, method, film build, and drying or cure sequence. A horizontal laboratory drawdown does not automatically represent a vertical sprayed surface or a reactive resin at greater thickness. Select a practical screen, then confirm the promising level under representative use conditions.
Assess gloss and surface profile separately where they are important. A coating can become glossier without meeting the required texture standard. Clarity and haze likewise require attention in transparent or high-appearance systems. A single favorable measurement should not conceal a defect detected by another relevant observation.
Include cure, adhesion, recoating, and the properties required for the finished article. The purpose is to determine whether improved surface appearance remains compatible with the full specification. A useful additive level should not be accepted solely because one crater count decreases if another critical property becomes unacceptable.
Repeat selected trials after storage and with representative raw material variation. A formulation should remain sufficiently robust to practical changes in resin lot, pigment treatment, and processing conditions. Where post-addition is planned, qualify that sequence separately rather than assuming it duplicates an addition made earlier in manufacture.

QUALITY CONTROL AND SCALE-UP

Incoming control should confirm the exact grade, batch identity, packaging condition, and documentation agreed for supply. Inspect the product for unusual contamination or appearance changes before dosing. Representative sampling and temperature control improve the usefulness of any physical test.
Density and nonvolatile matter can support consistency control when the methods are defined. Use the stated drying condition when comparing the typical residue value. A different laboratory procedure should not be treated as equivalent without checking its relationship to the intended specification.
An application control can reveal changes that a single analytical measurement does not capture. Use a stable reference formulation and a reproducible application method. If the reference resin or solvent changes, investigate its contribution before attributing an altered surface result to the additive.
Scale-up should verify circulation, dosing accuracy, temperature, and uniform distribution. The product's flexibility of addition stage does not eliminate poorly mixed zones in a larger vessel. Compare production samples with the laboratory qualification after equivalent conditioning and application.
Maintain traceability between additive batches, formulation records, process adjustments, and finished-product samples. This helps distinguish a product issue from a solvent change, contamination event, application fault, or alteration in drying or cure. A documented comparison is more useful than applying the same correction to every surface complaint.

HEALTH HAZARDS AND EXPOSURE CONTROL

The documented European classification includes flammable liquid Category 3, H226; specific target organ toxicity after single exposure Category 3 for respiratory irritation, H335; and Category 3 for drowsiness or dizziness, H336. It also includes chronic aquatic hazard Category 2, H411. The signal word is Warning, and repeated exposure may cause skin dryness or cracking under EUH066.
These are classifications of the supplied mixture and should be distinguished from the hazard profile of an isolated solvent ingredient. The disclosed aromatic solvent has its own component classification, including aspiration toxicity. A constituent classification should not simply be copied into the list for the whole grade without the applicable mixture assessment.
Control vapors and mist through suitable ventilation and handling methods. Avoid breathing emissions during opening, transfer, mixing, or cleanup. Headache, dizziness, tiredness, or respiratory discomfort can indicate overexposure and require prompt attention. Low addition levels in a final coating do not remove the hazards associated with handling the concentrated product.

Use chemical splash protection, protective clothing, and gloves selected for aromatic solvent exposure and the actual task. Fluoroelastomer gloves are identified in the safety guidance, but suitability depends on material, exposure duration, mechanical wear, and the rest of the chemical environment. Do not assume that any disposable glove provides adequate solvent protection.
Respiratory protection should be selected through the workplace exposure assessment where ventilation does not adequately control exposure or where a specific operation requires it. An approved organic-vapor filter system may be relevant, while unknown or dangerous atmospheres require a different response. Maintenance and spill tasks should be assessed separately from routine closed transfer.
Prevent skin contact and maintain normal industrial hygiene. Solvent exposure can remove natural skin oils even where the main classification does not include skin corrosion. Wash after handling, remove contaminated clothing, and avoid using solvent as a skin cleaner.

FIRST AID

For inhalation exposure, move the person out of the affected area to fresh air without exposing rescuers unnecessarily. Obtain medical advice after significant exposure, persistent symptoms, or breathing difficulty. If the person is unconscious, seek emergency assistance, protect the airway, and use an appropriate recovery position where suitable.

For skin contact, remove contaminated clothing and rinse the affected skin thoroughly with water, then wash appropriately. Obtain medical advice for persistent irritation or substantial exposure. Handle contaminated clothing so that it does not create additional skin or fire exposure before it is cleaned or disposed of.

For eye contact, rinse cautiously with clean water while keeping the eye open. Remove contact lenses if present and easy to do, and continue rinsing. Seek medical assessment if irritation persists or an injury is suspected. Avoid rubbing the eye or introducing another chemical in an attempt to neutralize the exposure.

If swallowed, keep the airway clear and obtain prompt medical or poison-center advice. Do not induce vomiting, do not give milk or alcoholic beverages, and never give anything by mouth to an unconscious person. The aromatic solvent content warrants particular care to avoid choking or aspiration during an incident.

Keep the product identity and relevant safety information available to responders. The exposure may also involve a coating, curing agent, or cleaning chemical, so provide the identity of the complete material where possible. Medical decisions should follow the actual circumstances and professional advice rather than the intended low-dose use of the additive.

HANDLING AND STORAGE

Store BYK-358 N in a dry, well-ventilated area suitable for flammable liquids, with containers tightly closed. Keep it away from heat, hot surfaces, sparks, open flames, and other ignition sources. Opened containers should be resealed carefully and kept upright to prevent leakage and solvent loss.
The stated shelf life is 60 months in unopened original packaging under the specified conditions. It does not automatically apply to material that has been contaminated, allowed to lose solvent, or stored improperly. Use batch identification and inventory rotation to preserve traceability.
Take precautions against static discharge during transfer. Suitable bonding, grounding, equipment selection, and ventilation should be established for the actual installation. Vapors can form flammable mixtures with air and may accumulate in low areas, so a room that appears clear at working height is not necessarily adequately controlled.

Open containers carefully and use appropriate transfer equipment. Minimize aerosol formation, splashing, and prolonged open handling. The selection of seals, hoses, pumps, and vessels should reflect compatibility with the aromatic solvent and the site's flammable-liquid requirements.
Avoid uncontrolled contact with acids and strong oxidizing agents. Keep product handling separate from incompatible chemical residues and unqualified cleaning procedures. Do not heat or dilute the material simply to address an unexplained change in appearance without first investigating the cause.
Empty packaging can retain flammable residues. Do not reuse containers casually, and do not burn, cut, or weld them as though they were free of chemical hazards. Manage contaminated packaging under the applicable waste and decontamination procedures.

FIRE, SPILLS, AND TRANSPORT

For a fire, use alcohol-resistant foam, dry chemical, or carbon dioxide as appropriate to the incident and surrounding materials. A high-volume water jet is unsuitable. Trained responders may use water spray to cool closed containers from a protected position, with measures to collect contaminated firefighting water.
Remove ignition sources and restrict access during a spill. Stop the leak if it is safe, contain the liquid, and collect it with noncombustible absorbent material. Use suitable equipment and closed waste containers, and avoid allowing vapors to accumulate in confined or low areas.
Prevent the product and cleanup residues from entering drains, soil, or surface water. The aquatic hazard makes containment especially important. If a release reaches a watercourse or drainage system, follow the site's reporting and emergency procedures for the actual location and scale of the event.
The documented transport identity is UN 1268, PETROLEUM DISTILLATES, N.O.S., Class 3, Packing Group III. The maritime entry identifies solvent naphtha in the shipping description. The product is environmentally hazardous under the stated land transport entries and is a marine pollutant for maritime transport.
Use current shipping documentation to determine the provisions for the actual route, mode, package, and quantity. Packing, closure, marking, labeling, and any applicable exceptions require separate attention. The transport entry for a finished coating or resin must be assessed for that complete formulation rather than copied from the additive.

ENVIRONMENTAL AND REGULATORY CONSIDERATIONS

BYK-358 N is classified as toxic to aquatic life with long-lasting effects under the documented European mixture classification. Avoid environmental release during storage, transfer, production, and waste handling. A low formulation dose does not justify uncontrolled disposal of concentrated residues or cleaning liquids.
No complete-product ready-biodegradability claim is established here. A biodegradability statement for a solvent constituent cannot be extended automatically to the polymer solution. Waste decisions should consider the entire composition and any contamination from coating ingredients, curing agents, or cleaning materials.
A November 2023 composition declaration gives a calculated VOC content of 48% under the stated European calculation framework. This is consistent with a solvent-containing supplied grade and should not be described as VOC-free. Finished-formulation calculations must include the additive's contribution and use the rules applicable to the relevant product and market.
The same dated declaration identifies trace constituents, including cumene and 1-methylimidazole in ranges of at least 0.01% and less than 0.1%, with certain additional constituents below 0.01%. Such disclosures are date-specific composition information, not a batch assay or a guarantee of analytical absence. Obtain current, specific documentation where an impurity limit is part of the intended qualification.

Food-contact information is application- and jurisdiction-specific. A March 2024 evaluation gives favorable compositional findings for certain European coating and printing-ink frameworks while recording noncompliance for use as a polymeric additive under Regulation (EU) No. 10/2011, under 21 CFR 175.300 for coatings, and under the stated Chinese coating and ink entries. These findings should retain their scope rather than become a worldwide approval or prohibition.
The food-contact evaluation excludes formulation aids and solvents from its stated status. Residual solvent, migration, intended contact conditions, and the complete article therefore require assessment. Current documentation is necessary before making a finished-product compliance claim, even when one compositional framework gives a favorable result.
Inventory and registration status must likewise be checked for the destination, supply route, and intended activity. Historical declarations contain market-specific qualifications and do not establish unrestricted worldwide supply. Statements about substances not intentionally added should retain any qualification about routine testing and absolute absence.

PRACTICAL PROBLEMS AND SOLUTIONS

Leveling remains insufficient
Check application viscosity, film thickness, solvent evaporation, and the time before cure or drying prevents flow. Compare a dose series within the relevant range. More additive cannot always overcome an excessively short flow window or a poorly balanced application process.

Cratering persists after addition
Investigate substrate contamination, cleaning residues, compressed air, overspray, and other additives. Confirm uniform incorporation and compare the defect on controlled reference panels. Crater-control chemistry should support clean production rather than conceal an ongoing contamination source.

Haze develops in a clear film
Compare wet and cured samples to determine when compatibility changes. Review resin polarity, solvent balance, addition level, and the drying sequence. A clear liquid blend does not establish compatibility after the faster solvents leave or the resin cures.

The coating looks glossier but still has unacceptable texture
Assess surface profile independently from gloss and compare at the same film build. A change in reflection intensity does not describe every wavelength of texture. Adjust the formulation and application toward the actual appearance requirement rather than one favorable number.

Solvent defects appear in a thick resin layer
Account for the carrier introduced with the additive and assess the route for solvent escape before gelation. Review film thickness, cure speed, and the supplied form selected. Do not assume that a nominally solvent-free host removes the carrier's contribution.

Recoating performance changes
Test the actual lower coat, topcoat, preparation, and recoat interval. Investigate cure and contamination alongside additive level. General positioning for good intercoat behavior does not replace finished-stack qualification.

Post-addition gives inconsistent results
Check the amount already present, mixing uniformity, batch temperature, and extra solvent. Confirm the correction on a representative laboratory sample before treating the full batch. Record the final total addition and the method used.

Unexpected odor, solids change, or viscosity shift is observed
Review container closure, solvent loss, contamination, and sampling conditions. Compare results using the agreed method and temperature. Do not correct an unexplained change by adding arbitrary solvent or filtering the material before the cause is understood.

FREQUENTLY ASKED QUESTIONS

What is BYK-358 N?
It is a polyacrylate-based leveling and anti-cratering surface additive supplied in alkylbenzene solvent.

Is it a pure chemical substance?
No. It is a commercial polymer solution with a significant solvent fraction.

Does the whole grade have one CAS number?
No single CAS number is specified here for the complete mixture; CAS 64742-95-6 identifies its disclosed aromatic solvent component.

Does it have one molecular formula or molecular weight?
No. Those single-molecule descriptors are not applicable to the complete polymer solution.

What is its typical density?
The typical density is 0.95 g/mL at 20°C.

What is its typical nonvolatile matter?
The typical value is 52% after 10 minutes at 150°C.

Is the supplied product solvent-free?
No. It contains alkylbenzene solvent even when evaluated in a nominally solvent-free host formulation.

Is it VOC-free?
No. A dated composition declaration gives a calculated VOC content of 48% under its stated framework.

What is its flash point?
The documented flash point is 47°C.

Is it miscible with water?
No. It is described as water-immiscible and should not be treated as a default aqueous-system additive.

What is its main formulation function?
Its main role is to improve leveling and help control cratering in suitable coatings and ambient-curing resin systems.

Does it strongly reduce surface tension?
It is documented as causing only a minor reduction rather than a strong universal wetting effect.

Can it support gloss?
Yes. Gloss and surface texture should still be evaluated separately in the finished coating.

Can it be used in clear coats?
It is positioned for compatible clear systems without unwanted turbidity, subject to confirmation in the actual formulation.

Can it be evaluated in pigmented coatings?
Yes. Check leveling, gloss, haze, color, and the complete surface appearance.

What is the coating dosage range?
The recommended starting range is 0.1–1% as supplied, based on the total formulation.

What is the ambient-curing resin dosage range?
The documented starting range is 0.1–0.5% as supplied, based on the total formulation.

How much nonvolatile material is in a 0.50 kg addition?
Using the typical 52% figure, it contributes approximately 0.26 kg of nonvolatile material.

How much volatile fraction accompanies that addition?
On the same nominal basis, approximately 0.24 kg accompanies a 0.50 kg addition.

Can it be added after manufacture?
Yes. Post-addition is permitted, provided uniform mixing and finished-product performance are verified.

Is a mandatory high-shear incorporation step specified?
No specialized high-shear requirement is assigned here, but adequate mixing for uniform distribution remains necessary.

Is it recommended for ambient-curing epoxy systems?
Yes. Qualify compatibility, surface behavior, cure, and the properties of the actual epoxy formulation.

Is it recommended for unsaturated polyester systems?
Yes. It is identified for suitable ambient-curing unsaturated polyester resin formulations.

Does it replace a defoamer or curing agent?
No. Leveling, foam control, and cure chemistry are distinct functions.

Does it guarantee recoatability in every layer sequence?
No. Its intended intercoat compatibility must be confirmed for the actual coatings and recoat conditions.

What is its stated unopened shelf life?
The stated shelf life is 60 months in unopened original packaging under the specified conditions.

What are its principal documented hazards?
They include flammability, respiratory irritation, drowsiness or dizziness, and chronic aquatic toxicity, with possible skin drying after repeated exposure.

What is its transport identity?
It is documented as UN 1268, petroleum distillates, not otherwise specified, Class 3, Packing Group III.

Is it a marine pollutant?
Yes. The documented maritime transport information identifies it as a marine pollutant.

Does favorable compositional food-contact information provide universal approval?
No. The jurisdiction, application, solvent residues, migration conditions, and complete finished article require specific assessment.

TECHNICAL SUMMARY AND SUPPLY DISCUSSION

BYK-358 N is a solvent-containing polyacrylate surface additive for improving leveling and resistance to cratering in suitable semi-polar to polar coating and ambient-curing resin systems. Its modest effect on surface tension distinguishes its role from that of a strong wetting additive. The intended result is a more uniform surface while preserving the clarity, haze behavior, and intercoat properties required by the complete formulation.
The supplied solution has a typical density of 0.95 g/mL and 52% nonvolatile matter under the stated drying method. This form is central to formulation calculations. The recommended coating range and the lower ambient-curing resin range refer to the complete product, and each addition also introduces aromatic solvent that must be included in emissions, processing, and safety assessments.

Practical qualification should connect addition level and incorporation with the available flow window, solvent evaporation, cure, application thickness, and substrate condition. A favorable wet appearance or gloss reading is not enough by itself. Clear-film compatibility, crater control, surface texture, cure, and any later coating or bonding operation should meet their own acceptance requirements.
Handling must reflect the 47°C flash point, vapor exposure considerations, and documented environmental hazard. Suitable flammable-liquid storage, ignition control, compatible equipment, spill containment, and current transport documentation are integral to reliable use. The stated 60-month unopened shelf life applies within its storage conditions and does not excuse contamination or solvent loss from an opened container.
For a technical discussion with Ataman Chemicals, provide the resin type, solvent package, pigment or filler content, application method, film thickness, drying or cure sequence, and the appearance issue being addressed. Include the intended recoat operation and any VOC, impurity, packaging, or food-contact requirement. This information supports a focused sample trial and review of the current product and supply documentation.

The practical value of BYK-358 N is established in a controlled comparison that meets the full finished-product requirement. Accurate dosing, a clear solvent balance, uniform incorporation, and representative application testing provide the basis for that result. A successful selection improves surface quality while remaining compatible with the process, cure, subsequent operations, and intended use.

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