BUTYL ACRYLATE

Butyl Acrylate is a reactive acrylic ester monomer used extensively in emulsion polymers, solution polymers, pressure-sensitive adhesives, architectural coatings, industrial coatings, sealants, textile binders, paper coatings, leather finishes, plastics modifiers and specialty chemical synthesis. Butyl Acrylate has CAS Number 141-32-2, EC Number 205-480-7, molecular formula C7H12O2 and molecular weight approximately 128.17 g/mol. The material is the n-butyl ester of acrylic acid and is supplied commercially as a clear, colorless liquid with a characteristic strong fruity odor, density approximately 0.89 g/cm³, boiling point around 145°C, freezing point around -64°C, vapor pressure around 4-5 mmHg at 20°C and flash point around 39-40°C. Butyl Acrylate is a highly reactive vinyl monomer that readily undergoes free-radical polymerization and copolymerization, so commercial product is normally stabilized with a polymerization inhibitor such as monomethyl ether of hydroquinone, commonly abbreviated MEHQ. The inhibitor system is oxygen dependent, making correct headspace, storage temperature, contamination control and inhibitor maintenance essential to safe monomer handling. Butyl Acrylate is widely regarded as a soft acrylic monomer because its polymers and copolymers provide flexibility, tack, low glass-transition temperature, impact resistance and film formation. The current Ataman Chemicals TDS, SDS and batch COA should control the exact commercial purity, inhibitor concentration, acidity, water, color, transport classification, storage conditions and shelf-life requirements for the supplied grade.

PRODUCT IDENTITY

Chemical Name: Butyl Acrylate
Preferred Systematic Name: Butyl prop-2-enoate
Alternative IUPAC Name: Butyl 2-propenoate
Alternative Chemical Name: Acrylic acid n-butyl ester
CAS Number: 141-32-2
EC Number: 205-480-7
EU CLP Index Number: 607-062-00-3
PubChem CID: 8846
Molecular Formula: C7H12O2
Molecular Weight: Approximately 128.17 g/mol
Structural Formula: CH2=CH-COO-(CH2)3-CH3
Chemical Class: Acrylic ester / unsaturated carboxylic-acid ester
Functional Group: Activated carbon-carbon double bond conjugated with an ester carbonyl
Physical Form: Liquid
Appearance: Clear, colorless liquid
Odor: Strong, characteristic fruity odor
Density / Specific Gravity: Approximately 0.89 g/cm³ near 20°C
Boiling Point: Approximately 145°C
Freezing Point: Approximately -64°C
Flash Point: Approximately 39-40°C closed cup
Vapor Pressure: Approximately 4-5 mmHg near 20°C
Relative Vapor Density: Approximately 4.4 relative to air
Water Solubility: Low; approximately 1-1.5 g/L near room temperature depending on source and test conditions
Organic Solubility: Miscible or readily soluble in many common organic solvents
Explosive / Flammable Range: Approximately 1.5-9.9% by volume in air in commonly cited reference data
Autoignition Temperature: Approximately 267°C in commonly cited reference data
Principal Function: Reactive monomer
Primary Polymer Function: Soft comonomer for acrylic and related copolymers
Commercial Purity: Common technical polymerization grades are approximately 99.5% minimum, subject to the current Ataman Chemicals specification
Typical Inhibitor: MEHQ / p-methoxyphenol / 4-methoxyphenol
Typical Commercial MEHQ Range: Commonly approximately 10-20 ppm, while other inhibitor levels can be supplied by grade
Typical Water Control: Common technical grades often specify water at not more than approximately 0.05%, subject to the current grade specification
Typical Acidity Control: Common technical grades often specify very low acrylic-acid equivalent acidity, subject to the current grade specification
Transport Name: Butyl acrylates, stabilized
UN Number: UN 2348
Transport Class: Class 3 flammable liquid
Current EU Harmonized Hazard Statements: H226, H315, H317, H319 and H335
NIOSH Recommended Exposure Limit: 10 ppm time-weighted average
EU Indicative Occupational Exposure Limit: 2 ppm long-term and 10 ppm short-term under the applicable indicative occupational limit framework
Historical IARC Evaluation: Group 3, not classifiable as to carcinogenicity to humans

SYNONYMS

Butyl Acrylate, n-Butyl Acrylate, N-Butyl Acrylate, Butyl 2-Propenoate, Butyl 2-propenoate, Butyl Prop-2-enoate, Butyl Propenoate, n-Butyl Propenoate, Acrylic Acid Butyl Ester, Acrylic Acid n-Butyl Ester, Acrylic Acid N-Butyl Ester, 2-Propenoic Acid Butyl Ester, 2-Propenoic Acid, Butyl Ester, Butyl Ester of Acrylic Acid, BA, n-BA, Acrylic Monomer BA, Butyl Acrylate Monomer, Butyl Acrylate Inhibited, Butyl Acrylate Stabilized, MEHQ-Inhibited Butyl Acrylate, 4-Methoxyphenol-Inhibited Butyl Acrylate, Butyl Acrylate Polymerization Grade, Butyl Acrylate Technical Grade, Butyl Acrylate BA, Butyl Acrylate 99.5%, CAS 141-32-2, EC 205-480-7, C7H12O2, UN 2348 Butyl Acrylates Stabilized

WHAT IS BUTYL ACRYLATE?

Butyl Acrylate is the n-butyl ester of acrylic acid.
The molecule combines a polymerizable acrylic double bond with a flexible four-carbon n-butyl ester group.
This molecular structure gives Butyl Acrylate high free-radical reactivity and produces polymers with relatively low glass-transition temperature.
Butyl Acrylate can form homopolymers and can copolymerize with a very wide range of vinyl monomers.
In industrial practice, the monomer is used mainly as a comonomer rather than as a pure homopolymer feed because copolymer design allows flexibility, tack, hardness, adhesion, weatherability and chemical resistance to be tuned.
Butyl Acrylate is a bulk industrial monomer and must be treated as both a flammable liquid and a polymerization-reactive chemical.

MOLECULAR STRUCTURE

Butyl Acrylate contains an activated carbon-carbon double bond conjugated with an ester carbonyl.
The double bond is the principal polymerization site.
The n-butyl ester group contributes hydrophobicity and flexibility.
Compared with methyl or ethyl acrylate, the longer butyl group lowers the glass-transition temperature of the corresponding polymer.
This makes Butyl Acrylate one of the most important soft acrylic monomers.
The molecule can also participate in addition reactions across the double bond in specialty organic synthesis.

SOFT MONOMER FUNCTION

Butyl Acrylate is commonly called a soft monomer because it reduces polymer hardness and glass-transition temperature.
Poly(n-butyl acrylate) has a very low glass-transition temperature and remains soft and rubbery at ordinary room temperature.
When Butyl Acrylate is copolymerized with harder monomers, the final polymer properties can be tuned over a wide range.
Methyl methacrylate, styrene and similar hard monomers increase hardness and block resistance.
Butyl Acrylate restores flexibility, impact resistance, film formation and tack.
This hard-monomer / soft-monomer balance is fundamental to acrylic coatings and adhesive design.

POLYMERIZATION REACTIVITY

Butyl Acrylate polymerizes readily through free-radical mechanisms.
The acrylic double bond is more reactive than an isolated non-activated alkene because the carbonyl group stabilizes radical intermediates.
Polymerization can be initiated by thermal initiators, redox systems, ultraviolet-generated radicals or other radical sources.
The reaction is strongly exothermic.
Uncontrolled polymerization can accelerate rapidly because heat increases radical generation and polymerization rate.
Safe commercial handling therefore depends on inhibitor, oxygen, temperature control and contamination prevention.

HEAT OF POLYMERIZATION

Acrylic monomer polymerization releases substantial heat.
Representative technical data place the heat of polymerization of Butyl Acrylate at approximately 500 kJ/kg.
This heat release is manageable in a properly designed polymerization reactor with controlled feed and cooling.
The same exotherm becomes hazardous during unintended storage polymerization because a tank or drum may have limited heat-removal capacity.
Temperature rise can accelerate reaction further and produce a self-heating runaway.
Storage and transfer systems should therefore be designed around prevention rather than reliance on emergency cooling alone.

INHIBITOR SYSTEM

Commercial Butyl Acrylate normally contains a polymerization inhibitor.
MEHQ is one of the most common commercial inhibitors.
MEHQ is also called monomethyl ether of hydroquinone, 4-methoxyphenol or p-methoxyphenol.
Typical technical Butyl Acrylate specifications use approximately 10-20 ppm MEHQ, although other inhibitor concentrations can be supplied.
The inhibitor suppresses premature radical polymerization during storage and transport.
Removing inhibitor before polymerization should be performed only within a controlled production process because uninhibited monomer is substantially more hazardous.

OXYGEN DEPENDENT INHIBITION

MEHQ inhibition requires oxygen to function effectively.
Commercial inhibited Butyl Acrylate should therefore not be stored under an oxygen-free inert atmosphere unless a different validated inhibitor and safety system has been specifically designed.
A suitable oxygen-containing headspace maintains inhibitor activity.
Historical and current handling guidance for acrylic esters emphasizes storage under air or another controlled oxygen-containing gas rather than pure nitrogen.
Oxygen concentration should remain within the range required by the supplied-grade handling guidance.
The exact tank-blanketing procedure should follow the current Ataman Chemicals SDS and monomer-storage instructions.

WHY PURE NITROGEN CAN BE DANGEROUS

Pure nitrogen blanketing can remove the oxygen needed for MEHQ inhibition.
As dissolved oxygen is consumed, the inhibitor becomes less effective.
The monomer can then become increasingly vulnerable to spontaneous or contamination-induced polymerization.
An inert atmosphere is often beneficial for oxidation-sensitive chemicals, but inhibited acrylic monomers are a major exception when their inhibitor depends on oxygen.
Tank design should therefore use the correct oxygen-containing blanket rather than applying a generic nitrogen-blanketing rule.

STORAGE TEMPERATURE

Butyl Acrylate should be stored cool and within the temperature limit defined for the inhibited grade.
Widely used technical guidance limits storage to approximately 35°C maximum, while many storage systems target temperatures below approximately 25-30°C.
Higher temperature increases inhibitor consumption, peroxide formation, vapor pressure and polymerization rate.
Direct sunlight and local hot spots should be avoided.
Tank temperature should be monitored continuously in bulk storage.
Any unexplained temperature rise can indicate contamination, recirculation failure or developing polymerization and requires immediate emergency response.

CONTAMINATION CONTROL

Contamination is one of the most important causes of accidental acrylic-monomer polymerization.
Peroxides, radical initiators, strong oxidizers, reducing agents, amines, strong acids, strong alkalis and certain metal contaminants can interfere with inhibitor balance or initiate reaction.
Dedicated loading and unloading lines are preferred.
Return lines should not contain residues from incompatible monomers, catalysts or polymerization initiators.
Transfer equipment should be clean and dry.
Cross-contamination from reactor systems into monomer storage should be prevented by physical and procedural safeguards.

PHYSICAL PROPERTIES

Butyl Acrylate is a low-viscosity mobile liquid at ordinary temperature.
Specific gravity is approximately 0.89.
The boiling point is approximately 145°C.
The freezing point is approximately -64°C.
The flash point around 39-40°C makes the material a flammable liquid under common hazard-classification systems.
Vapor pressure around 4-5 mmHg at 20°C means meaningful vapor can be generated even below the boiling point.

DENSITY

Butyl Acrylate has density approximately 0.89 g/cm³ near room temperature.
The liquid is therefore lighter than water.
Density supports storage-volume calculations and batch mass balance.
Mass-flow or gravimetric dosing is preferred where accurate monomer ratios are required.
The current commercial specification should control the exact acceptance range if density is included as a release test.

BOILING POINT

The normal boiling point is approximately 145°C.
This is well above ordinary storage temperature but low enough for vacuum or atmospheric purification operations to require careful inhibitor control.
Distillation of acrylic monomers requires specialized design because inhibitor can become depleted in vapor-rich or distilled fractions.
Uninhibited condensate can polymerize more readily than stabilized bulk monomer.
Industrial recovery and distillation systems should therefore maintain inhibitor and oxygen control throughout the process.

FREEZING POINT

Butyl Acrylate remains liquid at very low temperature.
The freezing point is approximately -64°C.
Ordinary cold-weather storage does not normally cause freezing.
Very low temperature can increase viscosity slightly but does not remove the need for inhibitor and oxygen control.
Condensation and water contamination can still occur when cold containers are exposed to humid air.

FLASH POINT

Butyl Acrylate has a flash point around 39-40°C closed cup.
The material can therefore generate ignitable vapor-air mixtures at moderately elevated ambient temperature.
Ignition sources, open flames, sparks and hot surfaces must be controlled.
Electrical equipment in hazardous areas should meet the applicable area classification.
Static electricity should be controlled through bonding and grounding during transfer.

VAPOR PRESSURE

Reference vapor pressure is approximately 4-5 mmHg at 20°C.
Butyl Acrylate vapor is heavier than air.
Vapor can therefore accumulate in low areas, pits or poorly ventilated spaces.
Closed transfer and local exhaust ventilation reduce exposure.
Vent systems should be designed for both flammable-vapor control and inhibited-monomer safety.

WATER SOLUBILITY

Butyl Acrylate has low but measurable solubility in water.
Published values are around approximately 1-1.5 g/L near room temperature.
The monomer therefore forms a separate organic phase when mixed with larger quantities of water.
Emulsion polymerization uses surfactants to disperse Butyl Acrylate droplets and monomer-swollen polymer particles in water.
Low water solubility is one reason emulsion-polymerization kinetics differ from fully water-soluble monomers.

ORGANIC SOLUBILITY

Butyl Acrylate is compatible with many common organic solvents.
This allows use in solution polymerization and specialty synthesis.
Solvent choice influences polymer molecular weight, viscosity, heat removal and final VOC profile.
Solvent contamination in stored monomer should nevertheless be avoided because it can affect inhibitor concentration, flash point and polymerization control.

REFRACTIVE INDEX

High-purity Butyl Acrylate has a refractive index around approximately 1.418 near room temperature.
Refractive index provides a rapid identity and purity check.
Water, butanol, acrylic acid and other organic impurities can shift the value.
The test temperature should be controlled.
Chromatographic analysis remains preferable for detailed impurity control.

APPLICATIONS

Architectural latex paints
Butyl Acrylate is a major soft comonomer in waterborne architectural acrylic and styrene-acrylic binders, providing film formation, flexibility and impact resistance.

Interior wall paints
Acrylic latex formulations use Butyl Acrylate to balance harder monomers and reduce film brittleness.

Exterior wall paints
Butyl Acrylate contributes flexibility and weatherability to exterior acrylic coatings when combined with suitable hard monomers and stabilizers.

Roof coatings
Flexible waterborne roof coatings can use high Butyl Acrylate content to maintain elongation and crack-bridging performance.

Elastomeric coatings
Soft acrylic binders containing Butyl Acrylate are used in elastomeric wall and waterproofing coatings.

Waterproofing membranes
Acrylic dispersions based partly on Butyl Acrylate can provide flexible films for liquid-applied waterproofing.

Automotive coatings
Butyl Acrylate is used as a comonomer in selected acrylic resins for automotive OEM and refinish coatings.

Industrial coatings
Acrylic copolymers containing Butyl Acrylate provide flexibility, adhesion and weather resistance in industrial finishes.

Metal coatings
Butyl Acrylate can soften acrylic binders used on metal surfaces and improve impact resistance.

Wood coatings
Waterborne acrylic wood coatings can use Butyl Acrylate to reduce brittleness and improve film flexibility.

Concrete coatings
Acrylic dispersions containing Butyl Acrylate can provide adhesion and flexibility on mineral surfaces.

Masonry coatings
Butyl Acrylate contributes to low-temperature film formation and crack tolerance in masonry paints.

Printing inks
Acrylic binders containing Butyl Acrylate are used in selected waterborne and solventborne printing inks.

Overprint varnishes
Butyl Acrylate can soften acrylic overprint binders and improve film flexibility.

Pressure-sensitive adhesives
Butyl Acrylate is one of the most important monomers for acrylic pressure-sensitive adhesives because it provides permanent tack and low glass-transition 
temperature.

Label adhesives
Waterborne acrylic label adhesives commonly contain substantial Butyl Acrylate content to achieve tack and peel adhesion.

Tape adhesives
Acrylic pressure-sensitive tape formulations use Butyl Acrylate with functional comonomers to balance tack, peel and shear.

Protective-film adhesives
Low-tack removable acrylic adhesives can use Butyl Acrylate with harder and functional monomers to tune peel force.

Medical pressure-sensitive adhesive research
Acrylic adhesive systems can include Butyl Acrylate in specialized skin-contact applications, but medical suitability requires dedicated purity, residual-monomer and biocompatibility control.

Construction adhesives
Waterborne and solution acrylic construction adhesives can use Butyl Acrylate for flexibility and adhesion.

Flooring adhesives
Acrylic dispersion adhesives use Butyl Acrylate to provide tack, flexibility and open time.

Carpet adhesives
Butyl Acrylate-containing latex binders can provide flexible adhesion for textile flooring systems.

Sealants
Acrylic sealant binders often contain Butyl Acrylate because the monomer lowers modulus and improves joint movement capability.

Caulks
Waterborne acrylic caulks use Butyl Acrylate-containing dispersions for flexibility and adhesion.

Textile binders
Butyl Acrylate is widely used in acrylic textile binders for nonwovens, back coatings, pigment printing and fabric finishing.

Nonwoven binders
Soft acrylic latexes containing Butyl Acrylate can bond fibers while retaining hand and flexibility.

Carpet backing
Acrylic and related copolymer binders can use Butyl Acrylate for flexible textile backing.

Pigment printing binders
Textile pigment-printing binders use Butyl Acrylate to reduce film brittleness and improve fabric hand.

Warp sizing
Butyl Acrylate-containing acrylic polymers can be used in selected warp-sizing formulations.

Textile thickeners
Crosslinked or associative acrylic polymers based partly on Butyl Acrylate can be used in specialty textile rheology systems.

Paper coatings
Butyl Acrylate is used in acrylic and styrene-acrylic binders for coated paper and board.

Paper saturation
Acrylic latexes can impregnate paper to increase strength and flexibility.

Paper adhesives
Butyl Acrylate-containing emulsions are used in selected paper converting and laminating adhesives.

Leather finishes
Acrylic dispersions containing Butyl Acrylate can provide flexible, abrasion-resistant leather topcoats and basecoats.

Leather impregnation
Soft acrylic binders can penetrate and reinforce leather without excessive stiffness.

Floor polishes
Acrylic copolymers containing Butyl Acrylate can be used in floor-polish and maintenance-polymer systems.

PVC impact modifiers
Butyl Acrylate is used in acrylic impact-modifier polymers for PVC and other plastics.

Core-shell impact modifiers
Polybutyl acrylate-rich rubbery cores can absorb impact energy in core-shell polymer modifiers.

Molding additives
Acrylic copolymers containing Butyl Acrylate are used as modifiers in selected molding compounds.

Extrusion additives
Acrylic polymers containing Butyl Acrylate can modify flexibility and impact behavior in extrusion applications.

Acrylic elastomers
Butyl Acrylate is an important monomer in acrylic elastomers designed for heat- and oil-resistant rubber applications when combined with suitable cure-site 
monomers.

Synthetic rubber modifiers
Butyl Acrylate can be copolymerized into specialty elastomeric systems to adjust softness and low-temperature properties.

Acrylic fibers
Butyl Acrylate can be used as a modifying comonomer in selected acrylic-fiber compositions.

Cement modifiers
Flexible acrylic latexes containing Butyl Acrylate are used in polymer-modified cement, mortar and concrete formulations.

Tile adhesives
Acrylic dispersion powders and latexes derived partly from Butyl Acrylate can improve flexibility and adhesion in construction formulations.

Waterborne primers
Butyl Acrylate-containing acrylic dispersions can provide substrate wetting and flexibility in primers.

Wood adhesives
Acrylic and hybrid adhesives can use Butyl Acrylate to reduce brittleness.

Lamination adhesives
Flexible acrylic copolymers based partly on Butyl Acrylate can be used in selected laminating systems.

Specialty chemical synthesis
The activated double bond undergoes addition reactions with a variety of nucleophiles and other reactants, making Butyl Acrylate a useful synthetic intermediate.

EMULSION POLYMERIZATION

Emulsion polymerization is one of the largest industrial uses for Butyl Acrylate.
The monomer is dispersed in water using surfactant and polymerized with water-soluble or redox initiator systems.
Polymerization occurs primarily in polymer particles rather than in the large monomer droplets.
This process allows high molecular weight at manageable bulk viscosity and good heat removal.
The resulting latex can often be used directly in paints, adhesives, textile binders and paper coatings.
Residual monomer is normally reduced through conversion control, post-polymerization and stripping.

SOLUTION POLYMERIZATION

Butyl Acrylate can also be polymerized in organic solvent.
Solution polymerization is used for solventborne acrylic resins, adhesives, coatings and specialty intermediates.
Solvent moderates viscosity and assists heat transfer.
Chain-transfer agents can be used to control polymer molecular weight.
The final polymer solution retains solvent and therefore has a VOC profile different from waterborne latex.
Solvent selection should consider flash point, solvency, reaction temperature and downstream use.

BULK POLYMERIZATION

Bulk polymerization uses little or no solvent.
The absence of solvent maximizes monomer concentration and polymerization heat generation per unit reactor volume.
Viscosity rises sharply as conversion increases.
Heat removal therefore becomes progressively more difficult.
Bulk Butyl Acrylate polymerization requires specialized reactor design and careful feed, initiator and temperature control.
Uncontrolled bulk polymerization should never occur in storage or transfer equipment.

COPOLYMERIZATION

Butyl Acrylate copolymerizes with a wide range of vinyl monomers.
Common partners include acrylic acid, methacrylic acid, methyl methacrylate, styrene, acrylonitrile, vinyl acetate, vinyl chloride and other acrylate or methacrylate esters.
Functional monomers can add carboxyl, hydroxyl, amide, epoxy, silane or crosslinkable groups.
The comonomer ratio determines glass transition, hardness, tack, solvent resistance and adhesion.
Polymerization process and molecular weight provide additional control over final performance.

METHYL METHACRYLATE COPOLYMERS

Methyl methacrylate is a common hard-monomer partner for Butyl Acrylate.
MMA raises hardness, block resistance and glass-transition temperature.
Butyl Acrylate reduces brittleness and supports room-temperature film formation.
The ratio is central to all-acrylic architectural coatings and many industrial acrylics.
Functional acrylic acid or methacrylic acid is often added at low concentration to improve colloidal stability and adhesion.

STYRENE ACRYLIC COPOLYMERS

Styrene is another important hard-monomer partner.
Styrene-acrylic latexes balance cost, water resistance, hardness and flexibility.
Butyl Acrylate supplies softness and film-forming ability.
Styrene raises hardness and hydrophobicity.
The combination is widely used in architectural coatings, construction polymers and paper applications.
Exterior durability requirements determine whether all-acrylic or styrene-acrylic systems are preferred.

VINYL ACETATE COPOLYMERS

Butyl Acrylate can be copolymerized with vinyl acetate.
The BA fraction increases flexibility and water resistance relative to unmodified polyvinyl acetate.
Vinyl acetate contributes cost efficiency and strong adhesion to many porous substrates.
These copolymers are used in selected adhesives and coatings.
Monomer feed strategy is important because reactivity ratios can create composition drift if not controlled.

ACRYLIC ACID COPOLYMERS

Small amounts of acrylic acid are frequently used with Butyl Acrylate.
Carboxyl groups improve latex stability, adhesion and post-crosslinking options.
Excess acid can raise water sensitivity and viscosity.
Neutralization increases polymer-water interaction and can alter rheology.
Pressure-sensitive adhesives often use carefully controlled acrylic-acid levels to improve cohesive strength and adhesion.

PRESSURE SENSITIVE ADHESIVES

Butyl Acrylate is one of the most important monomers for acrylic pressure-sensitive adhesives.
The low glass-transition temperature gives the polymer permanent tack at ordinary temperature.
Harder or functional comonomers are added to prevent excessive flow and improve shear resistance.
Acrylic acid or other polar monomers improve adhesion to higher-energy substrates.
Molecular weight and gel content control cohesive strength.
PSA design therefore balances tack, peel and shear rather than maximizing any one property.

ARCHITECTURAL COATINGS

Butyl Acrylate is a core monomer in many architectural acrylic dispersions.
The soft monomer improves film formation below room temperature and reduces cracking.
Hard monomers provide scrub resistance and block resistance.
Latex particle morphology and minimum film-forming temperature can be tuned through monomer composition.
Exterior binders additionally require ultraviolet stability, water resistance and dirt-pickup resistance.
The final formulation includes pigment, filler, dispersant, thickener, coalescent and other ingredients beyond the polymer binder.

TEXTILE BINDERS

Textile binders must bond fibers or pigments without making the fabric excessively stiff.
Butyl Acrylate provides softness and flexibility to the binder film.
Harder monomers increase wash resistance and durability.
Crosslinking monomers can improve wet strength and solvent resistance.
Binder Tg is selected according to hand, laundering and end-use requirements.

PAPER COATINGS

Paper-coating binders use Butyl Acrylate to provide flexibility and adhesion.
The acrylic polymer binds pigment particles to the paper surface.
The BA level affects coating flexibility, pick resistance and calendaring behavior.
Harder monomers improve blocking and surface strength.
Latex particle size and colloidal stability affect coating rheology.

LEATHER FINISHES

Leather finishes require flexible films that can bend repeatedly without cracking.
Butyl Acrylate provides softness and extensibility to acrylic leather coatings.
Hard monomers and crosslinkers improve rub resistance.
The balance determines feel, gloss, flex resistance and durability.
Waterborne acrylic dispersions allow low-VOC leather finishing compared with conventional solvent systems.

PVC IMPACT MODIFIERS

Polybutyl-acrylate-rich elastomeric phases are widely used in acrylic impact-modifier technology.
A rubbery acrylic core absorbs impact energy.
A harder outer shell provides compatibility and processability with rigid thermoplastics.
The low glass-transition temperature of Butyl Acrylate makes it particularly useful as the rubbery phase.
Core-shell particle design can improve impact strength while maintaining weatherability.

ACRYLIC ELASTOMERS

Butyl Acrylate can form the principal soft backbone of specialty acrylic elastomers.
Acrylic rubbers provide useful heat, oxidation and oil resistance compared with many general-purpose diene rubbers.
Cure-site monomers are incorporated because pure polybutyl acrylate lacks conventional sulfur-curing unsaturation.
The resulting elastomers are used in selected seals, hoses and under-hood applications.
The exact cure chemistry depends on comonomer functionality.

PRODUCTION

Butyl Acrylate is manufactured by esterification of acrylic acid with n-butanol.
Water is generated as the reaction by-product.
Acid catalyst and controlled distillation are commonly used to drive conversion and separate product.
Unreacted alcohol and acrylic acid are recovered and recycled where process design permits.
Polymerization inhibitor is required throughout purification because elevated temperature increases monomer reactivity.
Final product is purified to low water, low acidity, low color and controlled inhibitor concentration.

ESTERIFICATION CHEMISTRY

Acrylic acid reacts with n-butanol to form Butyl Acrylate and water.
The reaction is reversible.
Continuous water removal shifts the equilibrium toward ester.
Acrylic-acid excess or butanol excess can influence conversion and downstream separation.
Residual acid and alcohol must be reduced in the purified monomer.
Inhibitor and oxygen management remain essential during hot purification steps.

QUALITY CONTROL

Important Butyl Acrylate quality-control parameters include identity, purity, color, acidity, water, inhibitor concentration, appearance and selected trace impurities.
Polymer producers require stable monomer quality because impurities can affect reaction rate, molecular weight and latex stability.
Water content can alter emulsion-polymerization mass balance and may affect solution-polymerization systems.
Excess acrylic acid can change polymer composition and reactor pH.
Incorrect inhibitor level can create either storage risk or unexpected polymerization induction behavior.
The current Ataman Chemicals specification and batch COA should control commercial acceptance.

PURITY

Commercial polymerization-grade Butyl Acrylate is commonly specified at approximately 99.5% minimum purity.
Gas chromatography is normally used for assay and volatile impurity control.
Relevant impurities can include n-butanol, acrylic acid and isomeric ester material depending on production route.
High monomer purity improves polymerization reproducibility.
The exact minimum purity should be taken from the current commercial grade specification.

WATER CONTENT

Technical polymerization grades commonly control water to a low level such as approximately 0.05% maximum.
Excess water can alter monomer assay and process mass balance.
In solution polymerization, water can affect solvent compatibility and certain functional comonomers.
In emulsion polymerization, the process already contains water, but consistent monomer water content still improves recipe reproducibility.
Karl Fischer titration is commonly suitable for low-level moisture measurement.

ACIDITY

Residual acrylic acid contributes to acidity.
High acidity can change polymerization pH, surfactant behavior and copolymer composition.
Commercial Butyl Acrylate therefore uses a very low acidity specification.
Acidity is normally expressed as acrylic acid equivalent.
An increasing acidity value during storage can indicate contamination or degradation and should be investigated.

MEHQ CONTENT

Inhibitor concentration is a critical safety and quality parameter.
Common commercial specifications use approximately 10-20 ppm MEHQ.
Too little inhibitor reduces storage safety margin.
Excess inhibitor can increase polymerization induction time and alter process initiation if not accounted for.
The batch COA should therefore be checked before polymerization.
Removal or destruction of inhibitor should be done only in a controlled reactor-feed process.

COLOR

High-quality Butyl Acrylate is clear and colorless.
Commercial color is commonly controlled on the Pt-Co / Hazen scale.
Very low color is important for clear acrylic resins, coatings and adhesives.
Rising color can indicate oxidation, contamination, inhibitor degradation or thermal history.
An off-color batch should be investigated before use in color-sensitive applications.

CURRENT EU HARMONIZED CLASSIFICATION

Current EU harmonized classification assigns Butyl Acrylate the principal hazard statements H226, H315, H317, H319 and H335.
H226 means flammable liquid and vapor.
H315 means causes skin irritation.
H317 means may cause an allergic skin reaction.
H319 means causes serious eye irritation.
H335 means may cause respiratory irritation.
The current supplied-grade SDS should control the full label, precautionary statements and any additional non-harmonized classification.

SKIN SENSITIZATION

Butyl Acrylate is an important skin sensitizer.
Repeated skin exposure can lead to allergic contact dermatitis in sensitized individuals.
Once sensitization develops, small subsequent exposures can provoke a reaction.
Direct skin contact should therefore be prevented rather than treated as a minor nuisance exposure.
Chemical-resistant gloves should be selected from permeation data appropriate to acrylate monomers.

RESPIRATORY IRRITATION

Butyl Acrylate vapor can irritate the respiratory tract.
The current EU harmonized classification includes STOT SE 3 for respiratory irritation.
NIOSH recommends a 10 ppm time-weighted-average exposure limit.
The EU indicative occupational limit is lower for long-term exposure, with a 2 ppm long-term and 10 ppm short-term reference under the applicable framework.
Closed handling and local exhaust are therefore appropriate around unloading, sampling and reactor charging.

EYE AND SKIN IRRITATION

Liquid Butyl Acrylate causes skin irritation and serious eye irritation.
Splash goggles and face protection are appropriate for transfer and sampling.
Emergency eyewash and safety shower should be available where bulk monomer is handled.
Contaminated clothing should be removed promptly.
Skin should be washed thoroughly after exposure.

HISTORICAL IARC CONTEXT

The historical IARC evaluation for n-Butyl Acrylate is Group 3, meaning not classifiable as to carcinogenicity to humans.
This historical classification should not be misrepresented as proof of complete absence of long-term hazard.
Current workplace classification and exposure control should instead follow the present legal SDS and occupational-hygiene requirements.

TRANSPORT

Stabilized Butyl Acrylate is transported as UN 2348.
The proper shipping description is Butyl acrylates, stabilized.
The transport hazard class is Class 3 flammable liquid.
Transport packaging and tank requirements depend on mode and jurisdiction.
The current Ataman Chemicals SDS should control ADR, RID, IMDG, IATA and local transport details.
Unstabilized monomer should not be transported as though it were ordinary stabilized commercial product.

STORAGE

Butyl Acrylate should be stored cool, well ventilated and protected from heat, flame and direct sunlight.
The product must retain an effective inhibitor system.
A suitable oxygen-containing atmosphere is required for MEHQ-stabilized monomer.
Pure nitrogen blanketing should not be used unless a specifically engineered alternative stabilization system has been validated.
Storage temperature should remain below the limit defined by the current grade, commonly not above approximately 35°C.
Dedicated tanks, pipelines and transfer equipment reduce contamination risk.
First-in-first-out inventory management helps minimize overstoring reactive monomer.

TANK DESIGN

Bulk-storage tanks should be designed specifically for inhibited acrylic monomer.
Temperature monitoring, level control, pressure relief and suitable venting are required.
Recirculation can help maintain uniform inhibitor and temperature when designed correctly.
Dead legs and stagnant zones should be minimized.
Condensed monomer from vent systems can be inhibitor-depleted and should not be allowed to accumulate separately without appropriate stabilization.
Emergency response plans should address unexplained temperature rise and polymerization.

STATIC ELECTRICITY

Butyl Acrylate is flammable and transfer can generate static electricity.
Containers, tanks, hoses and transfer systems should be bonded and grounded.
Splash filling should be minimized.
Conductive transfer equipment should be used in accordance with hazardous-area design.
Static control is especially important during tanker loading and drum filling.

FIRST AID

After eye contact, rinse cautiously and continuously with water for several minutes and obtain medical attention.
After skin contact, remove contaminated clothing and wash thoroughly with soap and water.
After inhalation, move the affected person to fresh air and obtain medical attention if symptoms occur.
After accidental ingestion, rinse the mouth and obtain immediate medical guidance according to the current SDS.
A sensitized individual with dermatitis or respiratory symptoms should receive occupational-medical evaluation.

SPILL MANAGEMENT

Eliminate ignition sources and ventilate the area.
Prevent Butyl Acrylate from entering drains, soil and surface water.
Stop the leak only when this can be done safely.
Use suitable non-reactive absorbent for small spills.
Avoid absorbents or contaminants that can initiate polymerization.
Collected waste should be placed in compatible containers with appropriate stabilization and venting strategy.
Large spills require trained emergency response because of flammability, vapor exposure and polymerization risk.

FIRE RESPONSE

Butyl Acrylate is a flammable liquid.
Vapor can form explosive mixtures with air.
Suitable extinguishing media include foam, dry chemical or carbon dioxide as appropriate to the incident and current SDS.
Water spray can be used to cool exposed containers.
Heated monomer containers require particular caution because polymerization can increase pressure and heat.
Firefighters should use self-contained breathing apparatus in significant chemical fires.

ENVIRONMENTAL CONSIDERATIONS

Butyl Acrylate is moderately volatile and only slightly soluble in water.
Environmental release should be minimized because unreacted monomer can affect aquatic and atmospheric compartments.
Industrial polymerization normally converts most monomer into high-molecular-weight polymer.
Residual monomer in polymer dispersions is reduced through conversion and post-treatment.
Wastewater and off-gas controls should be designed for the specific manufacturing process.
The current SDS should control environmental-hazard labeling for the supplied grade.

REGULATORY CONSIDERATIONS

Butyl Acrylate is a high-volume industrial monomer subject to chemical registration, occupational exposure, flammable-liquid and transport rules.
The current EU harmonized classification includes flammability, skin irritation, skin sensitization, eye irritation and respiratory irritation.
Workplace limits vary by jurisdiction.
Polymerized Butyl Acrylate in a finished acrylic polymer has a different hazard profile from the free monomer.
Residual monomer specifications can be important for coatings, adhesives, food-contact systems, medical applications and low-odor products.
Food-contact, cosmetic, pharmaceutical and medical suitability should never be inferred solely from the monomer's industrial use history.
Ataman Chemicals can provide current technical and safety documentation for the exact supplied grade.

COMMON FORMULATION PROBLEMS

Polymerization starts too early
Initiator level, reactor temperature or inhibitor removal may be too aggressive. Review induction period, feed strategy and reactor heat removal.

Polymerization starts too slowly
MEHQ level, dissolved oxygen, low temperature or insufficient initiator may be delaying radical generation. Check the batch COA and process design.

Monomer storage temperature rises unexpectedly
Treat unexplained temperature rise as a potential polymerization emergency. Stop transfers, follow the emergency plan and do not rely on routine cooling alone.

Tank stored under pure nitrogen
MEHQ requires oxygen. Restore the validated oxygen-containing storage condition according to the current monomer-handling procedure.

Inhibitor level is below specification
Do not continue ordinary storage. Follow the approved inhibitor-restoration and safety procedure.

Inhibitor level is above normal
Polymerization induction can become longer. Account for the actual inhibitor concentration in reactor startup and quality review.

Monomer contains visible polymer
Premature polymerization or contamination has occurred. Isolate the material and do not send it through pumps, meters or filters without technical review.

Filter plugs during unloading
Polymer formation or contamination may be present. Stop transfer and investigate rather than forcing material through the system.

Monomer color increases during storage
Oxidation, heat exposure or contamination may be occurring. Check temperature, inhibitor, acidity and purity.

Acidity increases
Acrylic acid contamination or degradation may be present. Review the COA and storage history.

Water exceeds specification
Wet transfer equipment, tank washing residue or condensation may be responsible. Dry the system and investigate before polymerization use.

Emulsion polymerization coagulates
Surfactant balance, electrolyte, feed rate, initiator, temperature or contamination may be destabilizing the latex. Do not assume the monomer alone is 
responsible.

Latex particle size is too large
Nucleation conditions, surfactant level or feed profile may be incorrect. Review the emulsion-polymerization recipe.

Latex viscosity rises unexpectedly
Particle interaction, acid-neutralization level or high conversion may be responsible. Review composition and rheology.

Residual monomer is too high
Conversion is incomplete or post-polymerization stripping is insufficient. Optimize initiator finishing and removal steps.

Paint film is too soft
Butyl Acrylate fraction may be too high. Increase hard monomer or crosslink density.

Paint film is too brittle
Butyl Acrylate fraction may be too low or Tg too high. Increase soft-monomer contribution.

Paint blocks after drying
Binder Tg is too low or coalescent/plasticization is excessive. Reduce soft monomer or increase hard-monomer/crosslink contribution.

Paint fails to form film at low temperature
Binder Tg or minimum film-forming temperature is too high. Increase Butyl Acrylate or adjust coalescent strategy.

Exterior coating picks up dirt
A very soft acrylic surface can retain dirt. Increase surface hardness or use morphology/crosslinking strategies.

Pressure-sensitive adhesive has low tack
Polymer Tg may be too high or molecular weight too high. Increase Butyl Acrylate fraction or rebalance the copolymer.

Pressure-sensitive adhesive has poor shear
Polymer is too soft or molecular weight/gel content is too low. Increase hard or functional monomer and cohesive strength.

Adhesive leaves residue
Cohesive strength is too low relative to adhesion. Raise molecular weight, crosslinking or hard-monomer content.

Adhesive peels too easily
Polarity or tack may be insufficient. Adjust Butyl Acrylate, acrylic acid and hard-monomer balance.

Textile binder feels too stiff
Binder Tg is too high. Increase soft-monomer fraction or reduce excessive crosslinking.

Textile binder has poor wash resistance
Polymer is too soft or under-crosslinked. Increase crosslinkable functionality or hard-monomer fraction.

Paper coating picks poorly
Binder level or cohesive strength may be too low. Optimize polymer hardness and binder dosage.

Leather coating cracks on flexing
Acrylic film is too hard. Increase Butyl Acrylate content or reduce excessive crosslinking.

Leather coating is tacky
Polymer is too soft. Increase hard monomer or post-crosslinking.

PVC impact modifier gives low impact strength
Rubbery-core fraction, particle morphology or Butyl Acrylate conversion may be inadequate. Review core-shell design.

Acrylic elastomer is too soft
Butyl Acrylate content or plasticization may be too high. Increase harder comonomer or cure density.

Acrylic elastomer does not cure
Butyl Acrylate alone lacks the required cure-site functionality. Include an appropriate cure-site comonomer and curing system.

Solution polymer viscosity is too high
Molecular weight, solids or Butyl Acrylate conversion may be high. Adjust solvent, chain transfer and feed profile.

Solution polymer viscosity is too low
Molecular weight or solids may be insufficient. Reduce chain transfer or adjust initiator and feed.

Reactor temperature spikes
Feed or initiator addition is too fast for heat-removal capacity. Stop or reduce feed according to the validated emergency procedure.

Customer wants uninhibited Butyl Acrylate for storage
Uninhibited monomer should not be stored or transported like normal commercial inhibited grade. Inhibitor removal belongs inside a controlled polymerization 
process.

Customer asks whether nitrogen blanketing is recommended
Not for ordinary MEHQ-inhibited Butyl Acrylate. The inhibitor requires oxygen, so the supplied-grade storage procedure must be followed.

Customer asks whether MEHQ must be removed before polymerization
Not always. Many industrial processes polymerize inhibited monomer directly by using an initiator system and recipe designed for the actual inhibitor level.

Customer assumes all Butyl Acrylate grades use 10-20 ppm MEHQ
That range is common but not universal. Use the current Ataman Chemicals COA for the supplied grade.

Customer confuses Butyl Acrylate with Butyl Methacrylate
They are different monomers. Butyl Acrylate has an acrylic double bond without the alpha-methyl group and generally produces softer polymers.

Customer confuses n-Butyl Acrylate with tert-Butyl Acrylate
They are different ester isomers with different properties and polymer behavior. CAS 141-32-2 is n-Butyl Acrylate.

Customer wants one universal storage shelf life
Shelf life depends on inhibitor, oxygen, temperature, packaging and grade. Use the current supplied-product documentation.

FREQUENTLY ASKED QUESTIONS

What is Butyl Acrylate?
Butyl Acrylate is the n-butyl ester of acrylic acid and a major reactive monomer for acrylic polymers.

What is the CAS Number?
141-32-2.

What is the EC Number?
205-480-7.

What is the molecular formula?
C7H12O2.

What is the molecular weight?
Approximately 128.17 g/mol.

What is another common name?
n-Butyl Acrylate or Acrylic Acid n-Butyl Ester.

What is the appearance?
A clear, colorless liquid.

What is the boiling point?
Approximately 145°C.

What is the freezing point?
Approximately -64°C.

What is the density?
Approximately 0.89 g/cm³ near room temperature.

What is the flash point?
Approximately 39-40°C closed cup.

Is Butyl Acrylate flammable?
Yes. Current EU harmonized classification includes H226, flammable liquid and vapor.

Is Butyl Acrylate soluble in water?
Only slightly, at roughly 1-1.5 g/L near room temperature.

What is Butyl Acrylate mainly used for?
Acrylic polymers for paints, coatings, adhesives, sealants, textiles, paper, leather, plastics modifiers and related applications.

Why is Butyl Acrylate called a soft monomer?
It lowers polymer glass-transition temperature and provides flexibility, tack and film formation.

Can Butyl Acrylate homopolymerize?
Yes, but industrial use is dominated by copolymers designed for specific performance.

What monomers can it copolymerize with?
Common partners include methyl methacrylate, styrene, acrylic acid, methacrylic acid, vinyl acetate, acrylonitrile and other acrylic or vinyl monomers.

Is Butyl Acrylate used in pressure-sensitive adhesives?
Yes. It is one of the principal monomers used to provide tack and low Tg.

Is Butyl Acrylate used in architectural paint?
Yes. It is a major soft comonomer in all-acrylic and styrene-acrylic latex binders.

Is Butyl Acrylate used in textile binders?
Yes. It provides flexibility and soft hand in many acrylic textile binders.

Is Butyl Acrylate used in PVC impact modifiers?
Yes. Polybutyl-acrylate-rich rubber phases are widely used in acrylic core-shell impact modifiers.

Why is inhibitor added?
Butyl Acrylate can polymerize spontaneously, so inhibitor suppresses premature polymerization during storage and transport.

What inhibitor is commonly used?
MEHQ, also called 4-methoxyphenol or monomethyl ether of hydroquinone.

What MEHQ concentration is common?
Approximately 10-20 ppm is common for technical polymerization grades, but the actual batch COA controls.

Does MEHQ need oxygen?
Yes. Its inhibition mechanism depends on oxygen.

Should Butyl Acrylate be stored under pure nitrogen?
Not when using the ordinary MEHQ inhibition system unless a specifically validated alternative storage system has been designed.

What is the current EU harmonized hazard classification?
The principal harmonized hazard statements are H226, H315, H317, H319 and H335.

What is the NIOSH exposure limit?
NIOSH recommends 10 ppm as a time-weighted average.

What is the EU indicative occupational exposure limit?
The applicable indicative values are 2 ppm long-term and 10 ppm short-term.

What is the transport UN Number?
UN 2348 for Butyl acrylates, stabilized.

How should Butyl Acrylate be stored?
Cool, stabilized, protected from heat and contamination, with the correct oxygen-containing atmosphere and within the current grade temperature limit.

What documents should be checked before use?
Use the current Ataman Chemicals TDS, SDS and COA for purity, inhibitor, water, acidity, storage and transport requirements.

FINAL TECHNICAL SUMMARY

Butyl Acrylate is a defined reactive acrylic ester monomer with CAS Number 141-32-2, EC Number 205-480-7, molecular formula C7H12O2 and molecular weight approximately 128.17 g/mol.
It is the n-butyl ester of acrylic acid and is also known as n-Butyl Acrylate, Butyl 2-propenoate and Acrylic Acid n-Butyl Ester.
Butyl Acrylate is a clear, colorless liquid with density approximately 0.89 g/cm³, boiling point around 145°C, freezing point around -64°C and flash point around 39-40°C.

The monomer is widely used because it produces soft, flexible, tacky acrylic polymer segments with low glass-transition temperature.
Major applications include architectural paints, industrial coatings, pressure-sensitive adhesives, sealants, textile binders, paper coatings, leather finishes, PVC impact modifiers, acrylic elastomers and specialty synthesis.
Butyl Acrylate can be polymerized by emulsion, solution and other free-radical processes and can copolymerize with many acrylic, methacrylic, styrenic and vinyl monomers.
Commercial Butyl Acrylate is normally stabilized with a polymerization inhibitor such as MEHQ.
A common technical-grade MEHQ range is approximately 10-20 ppm, but the current batch COA controls the actual specification.
MEHQ inhibition is oxygen dependent, so ordinary inhibited Butyl Acrylate should not be stored under an oxygen-free pure nitrogen blanket.
Storage temperature should remain within the supplied-grade limit, commonly not above approximately 35°C, with lower temperatures preferred for long-term stability.

Contamination with initiators, peroxides, strong oxidizers, reducing agents, amines, strong acids, strong alkalis and other reactive materials should be prevented.
Current EU harmonized classification includes H226, H315, H317, H319 and H335.
NIOSH recommends a 10 ppm time-weighted-average occupational exposure limit, while the EU indicative framework uses 2 ppm long-term and 10 ppm short-term values.
Stabilized Butyl Acrylate is transported under UN 2348 as a Class 3 flammable liquid.
The historical IARC evaluation is Group 3, not classifiable as to carcinogenicity to humans.
Quality control should include purity, color, water, acidity, inhibitor concentration and appearance according to the intended grade.

For Butyl Acrylate technical specifications, acrylic polymer formulation support, emulsion and solution polymerization applications, MEHQ requirements, TDS, SDS, COA and commercial supply, contact Ataman Chemicals with the intended polymer system, monomer specification, inhibitor requirement, storage configuration and packaging need.

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