BUTYL METHACRYLATE (BMA)

Butyl Methacrylate (BMA) is a polymerizable methacrylic acid ester used to manufacture acrylic and methacrylic polymers with a useful balance of flexibility, water resistance, adhesion and film integrity. In this profile, Butyl Methacrylate (BMA) specifically means the normal-butyl, or n-butyl, isomer identified by CAS Number 97-88-1. Commercial BMA is normally supplied as a clear, colorless, stabilized liquid rather than as an uninhibited laboratory intermediate.
The molecule combines a reactive methacrylate double bond with a four-carbon ester side chain. During polymer manufacture, the double bond is incorporated into the polymer backbone while the butyl ester group remains as a pendant group. This structure allows Butyl Methacrylate (BMA) to modify the behavior of copolymers without functioning as a separate, freely migrating plasticizer. Relative to methyl methacrylate, the longer alkyl side chain generally increases hydrophobic character and lowers the glass-transition temperature of comparable polymer systems.
Butyl Methacrylate (BMA) is selected for solventborne acrylic resins, polymer dispersions, paints, wood finishes, automotive coatings, printing inks, adhesives, sealants and specialist polymer modifiers. Finished performance depends on comonomer selection, molecular weight, morphology, residual monomer and processing conditions. BMA is a monofunctional monomer; it does not independently provide the multifunctionality needed for a crosslinked network.
Two distinctions are central to responsible use. First, stabilized BMA requires storage conditions compatible with its inhibitor system, including adequate oxygen when MEHQ stabilization is employed. Second, scientific assessments of carcinogenic potential and legally applicable classification are separate matters. Neither a familiar commercial use nor successful incorporation into a polymer removes the need to control exposure to the unreacted monomer.

PRODUCT IDENTITY

Product designation: Butyl Methacrylate (BMA)
Chemical identity: n-Butyl methacrylate
CAS Number: 97-88-1
EC Number: 202-615-1
EU Index Number: 607-033-00-5
Molecular Formula: C8H14O2
Molecular Weight: 142.20 g/mol
Chemical family: Methacrylic acid esters; monofunctional methacrylate monomers
Condensed structural formula: CH2=C(CH3)C(=O)OCH2CH2CH2CH3
Physical form: Clear, colorless liquid under normal ambient conditions
Commercial form: Stabilized monomer, with inhibitor identity and concentration defined by the supplied grade
The formula and molecular weight describe the n-butyl methacrylate molecule. They do not describe the inhibitor molecule, a formulated blend containing BMA, or the molecular weight of a polymer manufactured from BMA. Commercial purity, moisture, acidity, color and inhibitor content must be taken from the applicable specification and batch certificate.
Butyl Methacrylate (BMA) must be distinguished from n-butyl acrylate, isobutyl methacrylate, sec-butyl methacrylate and tert-butyl methacrylate. These substances can differ substantially in polymer behavior and handling properties. A matching elemental formula does not establish equivalent structure, and an abbreviation on its own is insufficient for substitution approval.

SYNONYMS

Butyl Methacrylate, n-Butyl Methacrylate, Normal Butyl Methacrylate, BMA, n-BMA, nBMA, Butan-1-yl Methacrylate, Butyl 2-Methylprop-2-enoate, n-Butyl 2-Methylprop-2-enoate, Butyl 2-Methylpropenoate, n-Butyl 2-Methylpropenoate, Butyl 2-Methyl-2-propenoate, n-Butyl 2-Methyl-2-propenoate, Methacrylic Acid Butyl Ester, Methacrylic Acid n-Butyl Ester, Butyl Ester of Methacrylic Acid, n-Butyl Ester of Methacrylic Acid, 2-Methylacrylic Acid Butyl Ester, 2-Methylacrylic Acid n-Butyl Ester, 2-Methyl-2-propenoic Acid Butyl Ester, 2-Propenoic Acid 2-Methyl Butyl Ester, Butyl Methacrylate Monomer, n-Butyl Methacrylate Monomer, Stabilized Butyl Methacrylate, Stabilised Butyl Methacrylate, MEHQ-Stabilized Butyl Methacrylate, Butyl Methacrylate CAS 97-88-1, Butyl Methacrylate EC 202-615-1, Butyl Methacrylate Methacrylic Ester, n-Butyl Methacrylate Acrylic Resin Monomer
This list combines chemical synonyms, abbreviations and descriptive search terms. Stabilization descriptions identify commercial variants and apply only when the corresponding inhibitor system is present; they do not denote additional chemical substances.

CHEMICAL STRUCTURE AND NATURE

Butyl Methacrylate (BMA) is the ester derived from methacrylic acid and n-butanol. Its methacrylate group contains a terminal carbon-carbon double bond adjacent to an ester carbonyl, with a methyl substituent on the substituted alkene carbon. The n-butyl group is connected through the ester oxygen and retains a straight-chain arrangement.
Free-radical addition consumes the double bond and links BMA units into a carbon-carbon backbone. The resulting repeat unit can be written as -CH2-C(CH3)(COOCH2CH2CH2CH3)-. This repeat-unit representation describes polymer composition; it is not a claim that commercial poly(n-butyl methacrylate) has one fixed chain length or one molecular weight.
The ester group contributes polarity, while the butyl chain contributes hydrophobic character and segmental mobility. Polymer properties reflect the interaction of these features with chain architecture. Consequently, increasing the BMA fraction in a methyl methacrylate copolymer often softens the material, but the same change in a much softer acrylate copolymer can produce a different result.
BMA contains neither a free hydroxyl group nor a free carboxylic acid group. Formulations requiring reaction with isocyanates, epoxides or other curing agents normally introduce suitable functional comonomers. An ordinary butyl ester group should not be described as a universal, readily available crosslinking site under routine coating conditions.

PHYSICAL PROPERTIES

Butyl Methacrylate (BMA) is a low-viscosity organic liquid with an ester-like odor. The following values are representative identification and engineering-screening data rather than a combined sales specification. Where published measurements disagree, the relevant batch documentation and a method suited to the engineering question take precedence.
Appearance: Clear, colorless liquid.
Molecular weight: Approximately 142.20 g/mol.
Density: Approximately 0.89-0.90 g/cm3 near 20-25 °C.
Normal boiling point: Approximately 163-164 °C at about 101.3 kPa.
Dynamic viscosity: Approximately 1.0-1.1 mPa·s near 20 °C.
Closed-cup flash point: Representative value approximately 48.5 °C; documented values can differ with method and sample.
Vapor pressure: Approximately 2-3 hPa at 20 °C in commonly used datasets.
Relative vapor density: Approximately 4.9, with air taken as 1.
Water solubility: Limited; a representative value is approximately 0.36 g/L at 25 °C.
Partition coefficient: Representative log Kow approximately 3.
Refractive index: Published values near 20 °C are approximately 1.421-1.425; specify temperature, wavelength and method for acceptance testing.
Freezing or melting point: Published technical datasets differ, including values around -50 °C and -75 °C; confirm the relevant product data before low-temperature design.

Density and viscosity

The density of BMA is below that of water, so spilled bulk liquid can form a floating phase. This behavior does not prevent a dissolved fraction from entering the water. Density correction also matters when converting tank volumes into mass, particularly when receipt and dispensing temperatures differ.
The low viscosity of fresh BMA supports pumping and accurate metering. However, viscosity should remain close to the established incoming-material baseline. An unexplained increase, especially with warming, haze or suspended material, warrants investigation for contamination or polymer formation rather than adjustment of the pumping system alone.

Boiling behavior and volatility

BMA has a higher normal boiling point than methyl methacrylate, but appreciable vapor exposure remains possible during open handling, warm processing or spill response. Vapor can collect in poorly ventilated low areas. A high boiling point therefore cannot substitute for ventilation or ignition control.
The boiling point is not a storage-temperature limit. Self-heating polymerization can create a dangerous condition well below normal boiling, and the heat released can accelerate the reaction. Distillation and evaporative concentration require a separate engineering review because inhibitor and monomer may distribute differently between vapor and liquid.

Solubility and aqueous behavior

Butyl Methacrylate (BMA) is not water-miscible. In aqueous polymerization, the monomer is dispersed and transferred through the reaction system rather than assumed to form a homogeneous water solution. Surfactant selection, feed strategy and mixing therefore influence the success of an emulsion process.
BMA is compatible with many organic formulation media, but compatibility with a finished resin solution is a separate question. Solvent quality, polymer composition, solids content and temperature can produce haze or precipitation even when the monomer itself mixes readily with the liquid vehicle.
pH and acidity
A conventional aqueous pH value is not an intrinsic release specification for neat BMA. Residual methacrylic acid is more appropriately controlled by a defined acidity or acid-content method. When pH is reported for an aqueous extract or emulsion, the preparation procedure must accompany the result.

POLYMERIZATION AND FUNCTION

The principal industrial function of Butyl Methacrylate (BMA) is to contribute methacrylate repeat units to a polymer. Suitable radical initiation creates active chains that add BMA and compatible comonomers. Chain propagation, termination and transfer determine molecular weight and influence the viscosity and mechanical behavior of the resulting resin.
Polymerization is exothermic. Heat generation depends on the quantity reacting and the reaction rate, while heat removal depends on equipment geometry, cooling capacity, mixing and heat-transfer surfaces. A process that behaves acceptably in a small vessel may become unsafe at larger scale if those relationships are not evaluated.
Commercial stabilization delays unwanted polymerization during storage and transport; it does not make BMA incapable of reacting. The inhibitor also affects the induction behavior of a deliberate polymerization. Incoming inhibitor concentration should therefore be included when investigating changes in reaction onset or conversion.

In a copolymer, BMA functions as a property-adjusting building block. The n-butyl side chain generally makes a methyl methacrylate-rich resin more flexible and more hydrophobic. These effects can improve the balance between film formation and hardness, but increased softness can also reduce blocking resistance or high-temperature stiffness.
Poly(n-butyl methacrylate) is commonly associated with a glass-transition temperature near 20 °C. This is a representative polymer value, not a thermal transition of the liquid monomer. Molecular weight, tacticity, residual monomer, measurement method and thermal history can shift a measured polymer transition.
For preliminary copolymer design, a reciprocal-temperature mixing relationship may help estimate glass transition from component fractions, provided temperatures are expressed in kelvin. Such estimates do not predict all features of structured particles, phase-separated polymers or crosslinked networks. Actual film formation, tack, hardness and service temperature still require measurement.

INHIBITOR AND ACTIVE CONTENT

Butyl Methacrylate (BMA) is typically marketed at high monomer purity with a deliberately specified inhibitor concentration. MEHQ, also called 4-methoxyphenol or hydroquinone monomethyl ether, is a common stabilizer. Different commercial grades can contain different inhibitor amounts, so there is no single universal BMA inhibitor specification.
Documented commercial offerings include relatively low and higher MEHQ levels. Selecting a grade requires balancing the downstream process with the storage and transport conditions for which that grade is intended. Reducing inhibitor merely to shorten reaction induction can compromise stability and must not be treated as a routine warehouse adjustment.
MEHQ inhibition requires oxygen. An oxygen-free nitrogen blanket can undermine the stabilization system even while reducing the apparent flammability of the headspace. Storage atmosphere, dissolved oxygen, replenishment arrangements and ignition protection must be designed together. Pure oxygen enrichment is also inappropriate because it creates additional fire risk.
Monomer assay, inhibitor content and water content measure different attributes. A high assay result alone does not prove adequate stabilization. Conversely, a correctly inhibited material can still fail an application because of acidity, color or contamination. Release decisions should consider the full agreed specification and the material's storage history.

APPLICATIONS

Solventborne acrylic coating resins

Butyl Methacrylate (BMA) provides a useful composition variable in thermoplastic acrylic resins for clear and pigmented coatings. Copolymerizing BMA with harder monomers can reduce brittleness and help a film accommodate substrate movement. The target is a workable balance between flexibility, adhesion, drying behavior and resistance to mechanical damage.
For a solventborne resin, molecular weight and monomer composition must be considered alongside solvent selection. Increasing BMA does not guarantee lower solution viscosity at every solids content or compatibility with every solvent blend. Development work should compare viscosity, clarity, film appearance and application behavior after realistic storage and dilution.

Exterior and architectural coatings

BMA-containing acrylic binders can be used in exterior decorative and protective coating systems. The hydrophobic side chain can contribute to resistance to water uptake, while the acrylic backbone supports durable film design. Finished weathering performance depends on the full binder composition, pigments, stabilizers, substrate and exposure environment.
Butyl Methacrylate (BMA) should not be presented as independently making a coating waterproof or indefinitely resistant to ultraviolet light. Useful comparisons include wet adhesion, water whitening, flexibility after aging and retention of surface appearance. A change that improves one of these results may affect dirt pickup or blocking and should be evaluated as a formulation change.

Automotive and transportation coatings

In automotive coating resins, BMA can help adjust toughness and flexibility within an acrylic polymer. This can be valuable when a finish must resist minor deformation without losing appearance. Functional acrylic systems can incorporate BMA alongside hydroxyl-functional or other reactive monomers to provide the desired cure chemistry.
The finished coating's hardness, solvent resistance and chemical resistance depend strongly on crosslink density and cure conditions. BMA itself does not supply hydroxyl functionality for a polyurethane reaction. Resin design must therefore distinguish the segment that adjusts physical properties from the comonomer that provides the intended reactive site.

Wood finishes and furniture coatings

Butyl Methacrylate (BMA) can support clear acrylic resins used on wood and furniture. Its contribution to flexibility may help the finish tolerate dimensional changes in the substrate, while appropriate copolymer design preserves clarity and surface strength. Solvent selection and drying conditions affect leveling, grain appearance and defect formation.
Testing should include blocking under stacked conditions, print resistance, household chemical resistance and appearance after water contact. A resin that forms an attractive initial film may remain too soft for a particular furniture application. BMA concentration should be adjusted with those service requirements in view.

Metal coatings and primers

BMA-containing resins can serve as binders or binder components for metal surface coatings. The monomer provides flexibility and hydrophobic character, while other functional groups and formulation components establish substrate interaction and corrosion protection. Film continuity and adhesion remain essential to performance.
Butyl Methacrylate (BMA) is not a corrosion inhibitor in the same sense as a dedicated anticorrosive pigment or inhibitor additive. Salt exposure, wet adhesion and substrate pretreatment should be evaluated on the complete coating system. A flexible binder cannot compensate for poor surface preparation or an unsuitable pigment package.

Printing inks and overprint varnishes

In acrylic ink resins, BMA can adjust film flexibility and compatibility with suitable organic vehicles. This is useful when printed substrates bend or flex and require a coherent film. Resin molecular weight, solvent release and pigment interaction influence printability as much as the nominal BMA fraction.
For overprint varnishes, the balance between gloss, rub resistance and blocking is particularly important. Development should include realistic winding, stacking and drying conditions. Packaging applications additionally require an assessment of residual monomer, migration and the applicable food-contact framework when contact with food is intended.

Adhesive binders

Butyl Methacrylate (BMA) can be incorporated into acrylic adhesive polymers to modify flexibility, cohesion and compatibility with the substrate or formulation vehicle. It can be especially useful when balancing a harder methacrylate component with more flexible polymer segments. Adhesion improvement must be demonstrated for the actual substrate and bonding conditions.
An adhesive polymer must balance wetting, peel, tack and resistance to creep. More flexible composition can improve contact with a surface while decreasing high-temperature holding strength. Functional comonomers, molecular weight and any crosslinking strategy should be selected together rather than relying on BMA concentration alone.

Pressure-sensitive adhesive development

BMA may be used as a comonomer in selected pressure-sensitive adhesive designs, but its homopolymer is substantially firmer than polymers derived from very soft adhesive acrylates. It should therefore not be described as a universal soft monomer for every adhesive. Its effect depends on the composition it replaces.
In a soft adhesive matrix, BMA can provide a way to tune the cohesion and temperature response while retaining an acrylic polymer structure. Screening should compare peel, shear, loop tack and aging on representative substrates. Residual monomer and odor also require control, especially for enclosed or sensitive end uses.

Caulks and sealants

Butyl Methacrylate (BMA) can participate in the manufacture of acrylic binders for caulks and sealants. A successful binder must form a continuous film while retaining sufficient flexibility and adhesion after drying or curing. Fillers, surfactants and the selected polymer architecture influence water resistance and movement capability.
The monomer is normally consumed during binder manufacture; adding unreacted BMA directly to an existing sealant is not a general route to better flexibility. Any reactive formulation using free monomer needs a deliberately designed cure process, exposure controls and a residual-monomer target.

Waterborne acrylic dispersions

BMA can be incorporated through emulsion polymerization into waterborne acrylic dispersions. Because the monomer has limited water solubility, formulation and feed conditions affect monomer distribution and reaction behavior. Particle composition and structure can be used to balance film formation with mechanical properties.
The resulting dispersion must be assessed for particle size, coagulum, storage stability and residual monomer. A stable-looking fresh latex may still show poor mechanical stability or excessive water sensitivity after formulation. BMA selection should be connected to those measured results rather than to a broad claim that all methacrylate dispersions behave alike.

Textile binders and fiber treatment

BMA-containing copolymers can serve as binders and treatment agents for textile applications. Their role is to form a polymeric film around fibers or at fiber junctions, providing cohesion while maintaining an acceptable handle. The balance between softness and strength depends on the complete binder composition.
For textile finishing, practical checks include flexing, laundering, abrasion, yellowing and changes in touch. A binder designed only for maximum strength may make the fabric too stiff, while an overly soft film can feel tacky. Residual monomer control is especially relevant for products handled close to the body.

Paper coating and processing

Butyl Methacrylate (BMA) can be used in copolymer binders intended for paper treatment or coating. The binder helps attach particles to the surface and can modify flexibility and response to moisture. Surface porosity, coating weight and drying profile influence the observed result.
Paper converting introduces requirements such as fold resistance, printability and blocking that are not captured by a simple water-resistance test. Where the treated paper is intended for food packaging, the polymer formulation and finished article need the appropriate regulatory and migration assessment.

Leather finishing and coated fabrics

BMA-containing acrylic resins can contribute flexible films to leather finishes and related coated substrates. The aim is a coating that adheres through bending and handling while retaining the desired surface appearance. Compatibility with pigments, waxes and other finish components must be checked.
Performance evaluation should include repeated flexing, wet and dry rubbing, tack and adhesion after exposure to moisture. The BMA fraction helps adjust the film's physical balance, but it does not establish breathability, abrasion resistance or compliance with restricted-substance requirements on its own.

Concrete and construction additives

Butyl Methacrylate (BMA) can be a building block for polymeric additives used in construction-related coatings, sealers and modifiers. The practical role is usually delivered by the finished polymer or dispersion. Direct addition of BMA monomer to cementitious material should not be inferred from the existence of these applications.
For a polymer dispersion used with mineral binders, alkali stability, electrolyte tolerance, adhesion and water exposure are relevant. For a reactive resin system, cure development, shrinkage, heat generation and ventilation require separate qualification. These are different applications and should not share an assumed universal dosage.

Plastic modification and specialty copolymers

BMA can be used in tailored acrylic copolymers and structured polymer particles intended to modify plastics. The BMA-containing phase can influence compatibility, flexibility and the mechanical response of a modifier. Commercial utility depends on its interaction with the host polymer and any other phases present.
This use must be distinguished from treating liquid BMA as a conventional nonreactive plasticizer for PVC or polypropylene. Unreacted monomer can migrate, create odor and introduce handling hazards. A qualified polymer modifier has controlled composition and residual monomer rather than simply being a blend of plastic and free BMA.

Lubricant and oil-additive polymers

Methacrylate copolymers are used in lubricant-additive technology, and BMA can be part of selected monomer combinations. In these designs, alkyl-side-chain distribution and polymer molecular weight affect oil compatibility and temperature-dependent behavior. BMA is a possible building block, not a universal stand-alone viscosity improver.
The finished additive must be evaluated in the actual base oil and additive package. Low-temperature properties, shear response, clarity and deposit-related performance cannot be predicted from the identity of one comonomer. Liquid BMA should not be poured into a lubricant as a substitute for a purpose-made polymeric additive.

Specialist encapsulation and agricultural materials

BMA can be considered for selected copolymers used in encapsulation, coating or carrier technologies. In agricultural materials, such a polymer may provide a physical matrix or film rather than pesticidal activity. Release behavior depends on morphology, composition and the interaction with the incorporated substance.
Any agricultural use requires confirmation that the specific polymer and its residual monomers are acceptable for the intended formulation and jurisdiction. The use of BMA in a manufacturing route does not establish approval as an active ingredient, inert ingredient or formulation additive.

Specialty healthcare and laboratory polymers

BMA has a role in selected specialist polymer systems associated with healthcare materials, embedding media and research. In each case, performance and acceptability belong to the defined formulation and finished material. Industrial monomer must not be assumed suitable for direct clinical, dental or biological contact.
Qualification may require control of extractables, residual monomer, sterilization response and biological compatibility, depending on the actual application. These requirements can differ greatly between a laboratory embedding material and a medical device. The same CAS Number does not make commercial grades interchangeable across those uses.

FORMULATION GUIDANCE

Define the target property before changing the BMA fraction. For a methyl methacrylate-rich resin, an increase may improve flexibility but lower hardness or blocking resistance. In a soft acrylate-rich adhesive, the direction of the change can differ. Comparisons should therefore identify the monomer being replaced and maintain a clear record of composition.
Separate chemical composition from molecular weight. Two resins with the same BMA content can have very different solution viscosities, cohesive strengths and processing behavior if their chain lengths differ. A formulation study that changes initiator or chain-transfer conditions at the same time as BMA concentration can obscure the reason for the result.

Control the inhibitor contribution from all feeds. BMA, comonomers and recycled process streams may introduce different stabilization levels. A change in induction time or conversion profile should be examined against the actual incoming analysis, not just the nominal monomer recipe.
For a waterborne binder, distinguish polymer glass transition from minimum film-formation temperature. Particle morphology, water, surfactants and coalescing components influence how the dispersion forms a film. A calculated polymer transition is a useful development input but does not replace an application trial at the intended drying temperature.
For solventborne systems, evaluate the resin in the final solvent blend and at the intended solids content. Solubility of a low-molecular-weight sample does not guarantee clarity at higher molecular weight. Temperature cycling can reveal marginal compatibility that is hidden in a freshly prepared warm solution.
Introduce functional groups deliberately. BMA can be copolymerized alongside monomers bearing hydroxyl, acid or other suitable functionality, but those groups govern the corresponding cure reaction. Crosslinker demand should be calculated from measured or specified functionality rather than total BMA content.

Assess the finished material for odor and emissions. High conversion, appropriate finishing and controlled storage can reduce residual monomer, but odor alone is not an analytical release test. Application-specific acceptance should include residual BMA measurement when its concentration affects performance or exposure.
Use pilot-scale work to confirm both product behavior and process control. Record feed history, conversion, heat removal, solids, molecular weight and residual monomer so that a successful laboratory result can be interpreted. Numerical recipes, reaction temperatures and addition rates require a validated process and cannot be selected from a general product profile.

PRODUCTION AND PROCESSING

Butyl Methacrylate (BMA) can be manufactured by esterification of methacrylic acid with n-butanol or by ester interchange using a suitable methacrylate feedstock and n-butanol. Industrial purification separates excess reactants and other process components while maintaining appropriate stabilization. The production route influences which impurities deserve attention in the final specification.
Esterification generates water, whereas ester interchange can generate a different alcohol coproduct. These routes therefore have different separation requirements. Regardless of route, the release specification should control monomer identity, assay, acidity, water, color and inhibitor rather than relying on the production description alone.
Downstream polymer production can use solution, emulsion or other suitable polymerization approaches. Each method produces a different process environment and can lead to different polymer morphology and residual-monomer behavior. The selected route must match the intended resin form, solids content and application.
Purification or inhibitor removal changes the safety basis of the material. Fresh distillate can be inadequately stabilized even when the original feed was correctly inhibited. Such operations need validated inhibition, oxygen management, residence-time control and emergency provisions; they are not simple extensions of routine liquid transfer.

QUALITY CONTROL

Incoming-material identification
Confirm Butyl Methacrylate (BMA) identity through a suitable combination of chromatographic and spectroscopic methods. Identification should distinguish the n-butyl isomer from other butyl methacrylates and from butyl acrylate. Receipt documentation, container label and laboratory identity must agree before material is released to production.

Assay and related organic impurities
Gas chromatography is commonly appropriate for measuring monomer purity and relevant volatile organic impurities. The reported basis matters: normalized area percentage is not automatically equivalent to a fully corrected mass assay. Calibration, detector response and the treatment of water and inhibitor must be defined for the method.

Water content
Karl Fischer analysis can quantify water when a low-moisture specification is needed. The acceptance limit is grade-specific rather than a universal property of BMA. Sampling must avoid introducing moisture, and the analyst should recognize that a separate water phase can make a single small sample unrepresentative.

Acidity
Residual methacrylic acid can be measured by an appropriate titration or other validated method. Reports should state whether the result is expressed as methacrylic acid content or as an acid value. These quantities use different units and should not be exchanged without a proper conversion.

Inhibitor content
Measure inhibitor using a method suitable for its identity and expected concentration, such as a validated chromatographic procedure. This result supports both safe storage and interpretation of polymerization behavior. A satisfactory monomer assay does not replace direct inhibitor determination when inhibitor is a release criterion.

Color and appearance
Check appearance against an established visual standard and measure color on the agreed scale where required. Haze, sediment, unexpected yellowing or visible polymer should trigger investigation. Filtering a suspect batch until it looks clear does not establish that its chemical stability has been restored.

Physical identification checks
Density and refractive index can provide useful corroborating checks, provided temperature and instrument conditions are controlled. They are generally insufficient on their own to verify purity or distinguish all possible contaminants. A result near a literature value should be interpreted alongside the more selective analytical methods.

Application and polymerization checks
A standardized small-scale polymerization or resin-performance comparison may be useful for sensitive operations. Such a check should have its own validated safety procedure and acceptance criteria. Compare induction behavior, conversion, resin viscosity, color and residual monomer with a qualified reference lot.

Batch traceability
Retain batch number, receipt date, certificate, inhibitor information and relevant temperature history. If material is blended or transferred between vessels, preserve that traceability. A certificate documents the tested batch at a defined stage; subsequent contamination or adverse storage can change its condition.

Numerical release limits
High-purity industrial BMA is available under several commercial specifications, but no single set of assay, water, acidity, color and inhibitor limits defines every grade. The agreed technical specification and certificate control acceptance. A value copied from a different commercial grade should not become an assumed guarantee.

COMPATIBILITY AND MATERIALS OF CONSTRUCTION

Butyl Methacrylate (BMA) can copolymerize with many acrylic and methacrylic monomers, but chemical copolymerizability does not establish storage compatibility. Initiator-containing mixtures, curing-agent residues and contaminated recycled streams may reduce stability. Storage systems should be dedicated or cleaned and verified under a suitable procedure.
Materials of construction must resist the monomer and avoid introducing contaminants that can promote reaction. Appropriate metals and sealing materials should be selected using compatibility data for the actual grade, temperature and service duration. A material suitable for short sampling contact may be unsuitable for a continuously wetted seal.
Elastomer swelling can cause leakage, contamination or mechanical failure. Hose and gasket selection therefore requires more than a generic solvent-resistance claim. Maintenance should consider changes in hardness, dimensions and integrity, especially where repeated flexing or warm service occurs.
Keep BMA away from strong oxidizers and uncontrolled radical sources. Peroxides, initiator residues and certain reactive contaminants can create a polymerization hazard. Strong acid or alkaline contamination can also alter ester chemistry or corrode equipment, introducing additional process problems.

CURRENT EU HARMONIZED CLASSIFICATION

The harmonized classification entry identified for n-butyl methacrylate, EU Index Number 607-033-00-5, includes the following hazards:
Flam. Liq. 3, H226: Flammable liquid and vapor.
Skin Irrit. 2, H315: Causes skin irritation.
Eye Irrit. 2, H319: Causes serious eye irritation.
Skin Sens. 1, H317: May cause an allergic skin reaction.
STOT SE 3, H335: May cause respiratory irritation.
The associated basic labeling uses the flame and exclamation-mark pictograms and the signal word Warning. The supplied material's current SDS and legally applicable labeling requirements govern the actual consignment. Additional supplier assessments must be distinguished from the harmonized entry.
Regulatory information reviewed against accessible documentation on 15 October 2026. The latest consolidated legal entry could not be independently accessed during this review; the classification above is the established entry corroborated by the available technical documentation, and its current legal status should be confirmed before a labeling decision. A scientific cancer-hazard evaluation published in 2023 placed butyl methacrylate in Group 2B, meaning possibly carcinogenic to humans. This scientific grouping is not an EU CLP hazard category and does not by itself establish an H350 or H351 labeling requirement.
Any proposed classification, scientific opinion, assessment of regulatory needs or pending regulatory activity must be separated from a legally adopted classification and its application date. This profile does not treat a proposal or scientific grouping as an effective amendment to the harmonized entry. It also does not interpret the absence of a cancer hazard statement in that entry as proof that long-term exposure is harmless.

REGULATORY CONSIDERATIONS

For European supply, the substance identity, registration coverage, use conditions and safety communication must correspond to the actual supply chain. A REACH registration is not a blanket approval for every end use. The commercial grade and intended application remain relevant to compliance.
Butyl Methacrylate (BMA) has uses in polymer systems addressed by food-contact frameworks. In the United States, n-butyl methacrylate is among the monomers identified in 21 CFR 177.1010 for specified acrylic and modified acrylic plastics. This is conditional authorization for qualifying polymer materials, not approval to add free BMA to food.
Food-contact qualification requires checking the applicable material category, composition, restrictions, extractives or migration requirements and conditions of use. European assessment likewise requires examination of the current legislation for the particular polymer and finished article. An industrial monomer certificate alone cannot demonstrate finished-packaging compliance.

Healthcare, dental and cosmetic-related applications require a separate evaluation of the exact material and use. This profile does not designate ordinary BMA as pharmaceutical grade, medical grade or a universally permitted cosmetic ingredient. Residual monomer, impurities and the finished material's exposure conditions are central to any such assessment.
VOC definitions and workplace limits vary by jurisdiction and application. BMA's relative volatility does not make it automatically exempt from VOC controls. Where numerical workplace limits apply, use the current local requirement and distinguish an occupational exposure limit from a derived exposure assessment value or a product-emissions reference value.

SAFETY AND HANDLING

Butyl Methacrylate (BMA) presents combined flammability, irritation, sensitization and reactive-polymerization hazards. Handle it with closed transfer and effective ventilation wherever practical. Work practices should minimize both inhalation and skin contact, including during hose disconnection, sampling and maintenance.
Select gloves, protective clothing and eye protection using the actual SDS and permeation information for BMA. Disposable gloves of unspecified material and thickness should not be assumed to provide adequate protection. Splash tasks can require additional face protection, which supplements rather than replaces suitable eye protection.
Bond and ground appropriate conductive equipment during transfer and control sources of static discharge. Electrical installations and tools should match the area's flammability assessment. The representative flash point does not mean that operation below that temperature eliminates every ignition scenario, particularly when mist or warmer surfaces are present.

Use respiratory protection only within a suitable workplace program, with selection based on exposure and atmospheric conditions. Unknown concentrations, oxygen-deficient spaces and emergency response need a different assessment from routine handling. Odor should never be used as proof that respiratory protection or ventilation is unnecessary.
Avoid repeated low-level skin contamination. Sensitization can make later exposures problematic even when earlier contact caused little obvious irritation. Workers who develop rash or other symptoms should receive appropriate medical assessment and an occupational review of exposure conditions.
Keep sampling quantities small enough for the intended analysis and label them clearly. Samples taken from a suspect hot or reacting container should not be approached as ordinary quality-control work. The emergency procedure takes precedence over obtaining an analytical result.

FIRST AID

Eye contact
Immediately rinse the eyes with clean, gently flowing water for at least 15 minutes, keeping the eyelids open. Remove contact lenses if present and easy to remove, and continue rinsing. Obtain medical attention promptly, especially if pain, redness or visual disturbance occurs.

Skin contact
Remove contaminated clothing and wash the affected skin thoroughly with soap and water. Do not use organic solvents to clean the skin. Seek medical advice for persistent irritation, rash or a suspected allergic reaction, and clean or dispose of contaminated clothing appropriately.

Inhalation
Move the affected person to fresh air without exposing rescuers to danger. Obtain medical assistance if coughing, irritation, breathing difficulty or other symptoms persist. Emergency breathing support should be provided only by trained personnel using suitable protective measures.

Ingestion
Rinse the mouth and obtain prompt advice from a poison service or medical professional. Do not induce vomiting unless specifically directed by medical personnel. Never give anything by mouth to an unconscious person.

Information for medical assessment
Provide the exact product name, the current SDS and the circumstances of exposure. The treating professional should assess symptoms and manage the exposure appropriately. A product information page does not replace the consignment-specific emergency information.

STORAGE AND POLYMERIZATION PREVENTION

Store Butyl Methacrylate (BMA) in an approved cool, dry, well-ventilated location protected from direct sunlight and external heat. Apply the temperature range, shelf life and inspection requirements specified for the supplied grade. A temperature stated for one inhibitor level or packaging type is not a universal limit for all BMA consignments.
Keep containers properly closed to limit contamination and moisture ingress, while maintaining the storage system's designed breathing and pressure-relief arrangements. Do not confuse normal package closure with deliberate oxygen-free storage. For MEHQ-stabilized BMA, sufficient oxygen must remain available to support inhibition.

The storage atmosphere needs a validated design that addresses oxygen availability, flammability and gas quality together. A general recommendation to use pure nitrogen is unsuitable for the ordinary oxygen-dependent inhibitor system. Operators should not improvise oxygen addition, gas sparging or headspace adjustments without an approved procedure.
Bulk installations should monitor temperature and have appropriate alarms and emergency arrangements. A rising temperature without an external explanation can indicate polymerization. Increasing viscosity, unusual pressure or rapid changes in appearance provide further reasons for urgent evaluation, but temperature rise can precede an obvious visible change.
Minimize stagnant pockets, blocked-in heated sections and unverified contamination in transfer equipment. A small volume trapped near a heat source can experience conditions different from those in the main tank. Maintenance and cleaning procedures should account for the possibility of polymer deposits and residual initiator contamination.

Use stock rotation and preserve temperature history where practical. Passing a nominal shelf-life date does not automatically prove that material is unsafe, but extension requires qualified assessment rather than a visual check alone. A satisfactory inhibitor assay also does not independently establish safe storage if oxygen availability or contamination is uncertain.
If polymerization is suspected, isolate the area and activate the site's emergency response. Do not open, move, heat, tightly reseal or manually dose a suspect container in an attempt to restore normal condition. Emergency inhibition and cooling measures require an engineered system and trained personnel.

SPILL MANAGEMENT AND FIRE RESPONSE

For a spill, restrict access and eliminate ignition sources when this can be done safely. Ventilate appropriately and prevent entry into drains, pits and waterways. A large spill or any spill involving heating, unusual pressure or suspected reaction requires specialist emergency response.
Trained responders may use compatible inert absorbent for a manageable, stable spill under the site's procedure. Collect contaminated materials in suitable designated containers and preserve any required pressure-management precautions. Do not return recovered monomer to clean stock or assume that an absorbent makes the waste nonreactive.
Fire response must address both burning liquid and heat-induced polymerization in nearby containers. Appropriate extinguishing media can include suitable foam, dry chemical or carbon dioxide, according to the incident and current SDS. A direct high-pressure water jet can spread burning liquid and is generally unsuitable for attacking a pool fire.

Emergency responders may use water spray to cool exposed equipment from a protected position when conditions permit. Container rupture is possible if heating or polymerization produces pressure. Firefighters need suitable protective equipment and breathing apparatus, and contaminated firewater should be contained where feasible.
Waste handling must consider flammability, residual monomer and stabilization. Do not deliberately evaporate BMA waste or mix it with initiator waste. Disposal and recovery should follow the applicable rules through a competent waste-management route.

TRANSPORT CLASSIFICATION

The standard dangerous-goods identity for stabilized n-butyl methacrylate is UN 2227, n-BUTYL METHACRYLATE, STABILIZED, Class 3, Packing Group III. For ADR transport, the hazard identification number is 39, reflecting a flammable liquid capable of a violent spontaneous reaction.
Transport planning must maintain adequate stabilization throughout the expected journey, including delays and warm conditions. ADR special provision 386 addresses stabilization and circumstances requiring temperature control. Packaging, vessel geometry, temperature and journey duration form part of that assessment.
The transport entry applies to the described stabilized substance. A mixture containing BMA can require a different classification. Use the current transport section of the supplied SDS and the applicable modal rules rather than assuming that every BMA-containing formulation ships as UN 2227.

ENVIRONMENTAL CONSIDERATIONS

Prevent releases of Butyl Methacrylate (BMA) to soil, drains and surface waters. Limited water solubility does not mean zero dissolved exposure, and a floating organic phase can spread across water. Spill containment should therefore address both bulk liquid and contaminated water.
Environmental behavior depends on concentration, exposure conditions and the receiving system. Do not treat biodegradation potential as permission for uncontrolled disposal. Wastewater treatment acceptance must be assessed for the actual stream, including monomer concentration and other formulation components.
Some hazard communication systems use aquatic hazard statements that are not adopted in the same form under EU CLP. These differences must be interpreted within the relevant jurisdiction. They should not be resolved by copying every statement from unrelated SDS documents into one supposedly universal classification.
Finished polymers and unreacted BMA have different release and exposure profiles. Control of residual monomer can reduce emissions from a polymer product, but polymer incorporation does not establish a general environmental claim. End-of-life behavior depends on the finished material and waste route.

COMMON FORMULATION PROBLEMS

Unexpectedly long polymerization induction
Check incoming inhibitor content, dissolved oxygen in the reaction feed, initiator condition and the validated process sequence. The appropriate correction belongs to the reaction procedure; do not remove inhibitor from stored BMA as a routine troubleshooting shortcut.

Poor conversion or elevated residual BMA
Review feed completion, mixing, temperature control, initiator efficiency and the finishing stage. Confirm the analytical method before changing the process. Increasing heat or initiator without evaluating accumulated monomer can introduce additional risk.

Resin is softer than expected
Examine the actual copolymer composition and molecular weight. More BMA can soften an MMA-rich resin, while residual monomer may further depress the observed transition. Measure conversion and residuals before attributing every change to the designed BMA fraction.

Film remains tacky or blocks in storage
Compare drying conditions, molecular weight, residual solvent, residual monomer and polymer glass transition. A binder that forms a film easily can still be unsuitable under stacked or warm service. Adjust the complete formulation and repeat realistic application testing.

Haze or phase separation in a resin solution
Assess solvent quality, solids content, water ingress and composition drift. The monomer's miscibility with a solvent does not establish the finished polymer's solubility. Evaluate temperature cycling before accepting an apparently clear fresh blend.

Water whitening or loss of wet adhesion
Review the full binder and additive package, including surfactants, functional monomers and film formation. BMA can contribute hydrophobic character, but hydrophilic components and film defects may dominate the result. Confirm adequate drying before changing monomer composition.

Coagulum in a polymer dispersion
Investigate feed stability, local monomer concentration, contamination, mixing and colloidal stabilization. A change in BMA delivery or comonomer distribution may affect the process. Determine the cause before simply increasing surfactant, which can alter finished-film water sensitivity.

Unexpected color development
Check raw-material color, contamination, inhibitor history and thermal exposure. Review samples from different stages to locate the source. A color change accompanied by self-heating or viscosity increase requires a stability assessment before further processing.

Viscosity increase in stored monomer
Treat the change as a possible polymerization or contamination warning. Check temperature history and follow the site's assessment procedure. Do not thin the material, heat it or filter it back into service merely to restore the original handling appearance.

Water layer in a storage container
Investigate ingress and isolate the affected material. Phase separation can affect sampling and inhibitor distribution as well as quality. Removing visible 
water alone is not sufficient evidence that the remaining BMA meets its original safety and release requirements.

Incorrect butyl methacrylate isomer supplied
Compare CAS Number, identity analysis and the agreed specification. Similar names and identical molecular formulas do not make the isomers interchangeable. Requalification is required before using a different isomer in an established polymer recipe.

Poor performance after replacing butyl acrylate
Review the structural and glass-transition differences between butyl acrylate and BMA. The alpha-methyl group changes polymer behavior, so a one-for-one replacement can change tack, flexibility and process response. Redesign the composition against measured target properties.

Oxygen-free storage proposed for MEHQ-stabilized BMA
Reassess the stabilization design before implementing the change. MEHQ requires oxygen, so a conventional pure-nitrogen blanket can undermine protection against polymerization. Storage atmosphere and fire precautions require a coordinated engineering solution.

Food-contact or healthcare compliance assumed from CAS identity
Obtain documentation for the exact grade and intended finished material. A monomer listing or a historical application does not establish purity, migration, extractables or biological compatibility for a new use. Qualification must follow the applicable product framework.

Scientific cancer grouping copied into the EU hazard label
Separate the scientific evaluation from the legally applicable CLP entry and any additional supplier assessment. Group 2B does not translate automatically into a specific CLP category. Equally, omitting a cancer statement from one label does not justify dismissing the scientific assessment.

FREQUENTLY ASKED QUESTIONS

What is Butyl Methacrylate (BMA)?
Butyl Methacrylate (BMA) is the n-butyl ester of methacrylic acid and a monomer for acrylic and methacrylic polymers.

What is the CAS Number of BMA?
The CAS Number for n-butyl methacrylate is 97-88-1.

What is the EC Number?
The EC Number is 202-615-1.

What are the molecular formula and molecular weight?
The molecular formula is C8H14O2 and the molecular weight is approximately 142.20 g/mol.

Does BMA mean every butyl methacrylate isomer?
No. In this profile BMA means n-butyl methacrylate; other isomers have different identities and properties.

Is BMA the same as butyl acrylate?
No. BMA contains an additional methyl substituent at the polymerizable group and gives different polymer behavior.

What does BMA look like?
Fresh commercial BMA is normally a clear, colorless, low-viscosity liquid with an ester-like odor.

Is Butyl Methacrylate (BMA) water-soluble?
BMA has limited water solubility and is not water-miscible; representative data give about 0.36 g/L at 25 °C.

What is the boiling point of BMA?
The normal boiling point is approximately 163-164 °C at atmospheric pressure.

What is the flash point?
A representative closed-cup value is approximately 48.5 °C; use the supplied SDS for the applicable measured value.

Why are different freezing points reported?
Published datasets differ, so low-temperature engineering should use verified data for the actual material and measurement method.

What does BMA do in a polymer?
BMA adds repeat units that can adjust flexibility, hydrophobicity, film behavior and compatibility within a suitable copolymer.

Does BMA always make a polymer softer?
No. It commonly softens MMA-rich polymers, but the effect depends on which monomer it replaces and the full composition.

What is the glass-transition temperature of its homopolymer?
A representative value for poly(n-butyl methacrylate) is near 20 °C, with variation from polymer structure and measurement conditions.

Is BMA a crosslinker?
BMA is monofunctional and does not independently provide the multiple polymerizable groups required for network formation.

Does BMA contain a hydroxyl group for polyurethane curing?
No. Suitable hydroxyl functionality must come from another component or an appropriately designed functional copolymer.

Why is commercial BMA stabilized?
An inhibitor helps limit unintended polymerization during specified storage and transport conditions.

What is MEHQ?
MEHQ is 4-methoxyphenol, also called hydroquinone monomethyl ether, and is a common BMA inhibitor.

Does every BMA grade contain the same amount of inhibitor?
No. Inhibitor identity and concentration are grade-specific and should be checked on the specification and certificate.

Can MEHQ-stabilized BMA be stored under pure nitrogen?
An oxygen-free nitrogen atmosphere is unsuitable for the ordinary MEHQ stabilization system because MEHQ requires oxygen.

Should oxygen be added directly to a storage tank?
Do not improvise oxygen addition; atmosphere control must follow a validated design that addresses inhibition and flammability together.

Is there one universal BMA storage temperature or shelf life?
No. Follow the limits and inspection requirements for the supplied grade, packaging and stabilization system.

Can BMA polymerize in storage?
Yes. Heating, contamination or inadequate stabilization can initiate polymerization and potentially cause self-heating and pressure buildup.

What should be done if a BMA container warms unexpectedly?
Isolate the area and activate the site's emergency procedure; do not treat a suspect container as routine sampling or transfer work.

Which quality-control tests are most useful?
Identity, assay, related impurities, water, acidity, color and inhibitor content are principal checks, supplemented by application-specific testing.

Is BMA approved for direct addition to food?
This profile makes no such claim; polymer food-contact provisions apply only under their specified material and use conditions.

Is ordinary industrial BMA automatically suitable for medical or cosmetic use?
No. The exact grade and finished application require separate documentation and qualification.

What is the standard transport identity?
Stabilized n-butyl methacrylate is generally UN 2227, Class 3, Packing Group III, subject to the applicable transport rules.

How should the 2023 Group 2B cancer assessment be understood?
It is a scientific evaluation of possible carcinogenic hazard and does not automatically change the legally applicable EU harmonized classification.

How can technical and commercial information be obtained?
Contact Ataman Chemicals for the applicable specification, TDS, SDS, COA and commercial supply information.

FINAL TECHNICAL SUMMARY

Butyl Methacrylate (BMA), CAS Number 97-88-1 and EC Number 202-615-1, is a defined n-butyl methacrylate monomer with molecular formula C8H14O2 and molecular weight approximately 142.20 g/mol. Its principal value is as a building block for polymers whose flexibility, water resistance and film behavior need to be balanced against hardness, cohesion and service temperature.

The n-butyl ester side chain generally increases hydrophobic character and reduces glass-transition temperature relative to an otherwise comparable methyl methacrylate polymer. This relationship supports applications in coating resins, adhesives, inks, sealants, polymer dispersions and specialty modifiers. The benefit belongs to the complete polymer design; BMA does not independently guarantee adhesion, crosslinking, weather resistance or suitability for a regulated end use.
Commercial selection should consider both purity and stabilization. Identity, assay, water, acidity, color, inhibitor content and relevant impurities influence consistent processing. A certificate of analysis is most useful when interpreted together with batch traceability and storage history. Conflicting literature values for selected physical properties should be resolved using the method and material appropriate to the engineering decision.

Safe use requires managing flammability, irritation, sensitization and polymerization together. MEHQ-stabilized BMA needs adequate oxygen, making oxygen-free nitrogen storage unsuitable for the ordinary stabilization system. Temperature monitoring, contamination prevention, appropriate transfer equipment and a practiced emergency response are essential parts of the storage and handling basis.
The identified EU harmonized entry addresses flammability, skin and eye irritation, skin sensitization and respiratory irritation. The 2023 scientific Group 2B assessment is a separate cancer-hazard evaluation and must not be confused with an automatically applicable EU classification amendment. Food-contact, healthcare and other sensitive applications require documentation for the exact grade and finished material.

For Butyl Methacrylate (BMA) technical specifications, TDS, SDS, COA and commercial supply, contact Ataman Chemicals. The appropriate commercial grade should match the downstream process, agreed quality limits, storage system and intended application.

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