| HS Code | 102039 |
| Chemical Formula | C7H12O2 |
| Molecular Weight | 128.17 g/mol |
| Cas Number | 4655-34-9 |
| Appearance | Colorless liquid |
| Odor | Ester-like odor |
| Density | 0.885 g/cm3 at 25°C |
| Boiling Point | 126-127°C |
| Melting Point | -72°C |
| Flash Point | 27°C (closed cup) |
| Refractive Index | 1.411 at 20°C |
| Solubility In Water | Insoluble |
| Vapor Pressure | 5 mmHg at 20°C |
As an accredited Isopropyl Methacrylate factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Isopropyl Methacrylate is packaged in 1-liter amber glass bottles with PTFE-lined caps, purged with nitrogen to ensure stability. |
| Container Loading (20′ FCL) | Isopropyl Methacrylate shipped in 20′ FCL: full container load, drums properly secured, ventilated, with flammable liquid handling precautions. |
| Shipping | UN 3272, Esters, n.o.s. (Isopropyl methacrylate, inhibited), Class 3, Packing Group II. It is a flammable liquid; use approved hazardous-material packaging, ground/vent containers, and segregate from oxidizers. Ensure inhibitor (MEHQ) is present to prevent polymerization. Comply with IATA, IMDG, and 49 CFR regulations. |
| Storage | Store isopropyl methacrylate in a cool, dry, well-ventilated area away from heat, sparks, open flames, and direct sunlight. Keep the container tightly sealed, protected from physical damage, and separate from oxidizing agents, acids, and bases. Ensure inhibitor presence and adequate oxygen to prevent polymerization. Use grounding and explosion-proof equipment, and inspect periodically for peroxides. |
| Shelf Life | Shelf life is typically 6–12 months when stored cool, dark, and with inhibitor; avoid heat and light to prevent polymerization. |
High-solids acrylic polyols intended for automotive OEM clearcoats are produced with isopropyl methacrylate (iPMA) as a hydrophobic comonomer when the resin target is a combination of low VOC, high crosslink density after 1K melamine or 2K isocyanate cure, and resistance to acid etch and scratch. The monomer has a molecular weight of 128.17 g/mol, density of 0.885 g/cm³ at 20 °C, and its homopolymer reports a glass transition temperature near 81 °C. In acrylic polyol synthesis, iPMA is charged at 5–25 wt% of total vinyl monomers, often replacing 10–30% of n-butyl methacrylate or isobutyl methacrylate to reduce solution viscosity while increasing film hardness. The reaction is run in a stainless steel reactor with partial condenser, nitrogen sparge, and external cooling; monomer and initiator are fed over 4–6 h at 135–145 °C using di-tert-amyl peroxide or tert-butyl peroxy-2-ethylhexanoate as initiator, with chain transfer by mercaptopropionic acid or alpha-methylstyrene dimer. The resulting acrylic polyol at 60–70 wt% solids typically shows a hydroxyl number of 80–120 mg KOH/g, and is let down in aromatic hydrocarbon/ester blends for automotive clearcoat application. Compliance pathways include EU REACH SDS alignment to Commission Regulation (EU) 2020/878, GHS classification entries H226, H315, H319, and H335, VOC verification under ASTM D7867-13, accelerated weathering under SAE J2527, and stone-chip resistance under ISO 20567-1. End-use coatings based on these resins are applied as low-bake OEM clearcoats and repair clearcoats at dry film thickness of 35–50 µm. Operating boundaries: iPMA levels above 25 wt% of total monomers can shift copolymer glass transition temperature too high, reduce intercoat adhesion on flexible substrates, and increase brittle failure in multi-impact stone chip testing; monomer with excessive inhibitor can also depress radical initiation in the synthesis. Residual monomer stripping above 160 °C may produce dimer or oligomer haze, so vacuum and temperature ramps are controlled.
In ultraviolet-cured clear topcoats for wood flooring and plastic panels, isopropyl methacrylate is incorporated as a monofunctional methacrylate diluent to reduce viscosity without lowering the glass transition temperature of the cured network to the same extent as aliphatic monoacrylates. Formulation addition ratio is typically 10–30 wt% of the total UV-curable formulation; at those levels the Brookfield viscosity of a polyurethane acrylate formulation can be reduced from 1,200–2,500 mPa·s to 300–700 mPa·s at 25 °C depending on oligomer type. The downstream process consists of high-speed dispersion of photoinitiator and additives into the oligomer/monomer blend, followed by roller coating or curtain coating at 10–40 g/m² wet film and UV cure under a 395 nm LED line or 80–120 W/cm mercury arc lamp. For a 3–6 J/cm² UVA dose and 8–12 W/cm² peak irradiance, acylphosphine oxide photoinitiator at 2–4 wt% is common; oxygen inhibition at the coating surface requires nitrogen inerting or high peak irradiance because iPMA as a methacrylate cures more slowly than acrylate diluents in air. Compliance for furniture and wood applications includes VOC limits under EU Directive 2004/42/EC Annex IIB, migration of certain elements under EN 71-3 when the coated article may be used as a toy, adhesion testing under ASTM D3359 method B, and general chemical safety under EU REACH. End-product types include furniture lacquers, parquet and wood flooring topcoats, and clear protective coats on PVC edgebands and interior plastic panels. A process limitation is that residual hydroquinone monomethyl ether in unpromoted iPMA can raise photoinitiator consumption and slow surface cure; nitrogen-blanketed UV lines and inhibitor-stripped monomer grades are therefore used when through-cure below 5 µm is required.
Anaerobic single-component adhesives are formulated with methacrylate ester monomers that remain liquid in the presence of air and polymerise only when oxygen is excluded by close-fitting metallic joints. In these systems, iPMA is dosed at 5–15 wt% of the monomer blend to reduce odour relative to methyl methacrylate, lower viscosity, and increase the hydrophobic character of threadlocking and retaining compounds; the monomer still participates in the radical cure driven by saccharin and N,N-dimethyl-p-toluidine. Production mixing is performed under nitrogen blanketing in stainless steel or coated vessels, with dissolved oxygen maintained at 2–5 ppm to prevent premature polymerisation. Stabiliser packages include hydroquinone monomethyl ether at 20–60 ppm, a metal chelator such as EDTA disodium salt, and free-radical stabiliser to meet shelf-life requirements of 12–24 months; accelerators and initiators are added post-dissolution to avoid uncontrolled exotherms. Final product is packaged into high-density polyethylene containers and tested for fixture time, breakaway torque, and prevailing torque under ASTM D5649 and ISO 10123:2013, with product classification under ASTM D5363-16. End-product types include low-to-medium strength threadlockers, retaining compounds for cylindrical bearings, and anaerobic flange sealants. The operational boundary is that highly passive surfaces, such as stainless steel with low metal ion availability, require surface activators because iPMA-containing formulations do not cure indefinitely in large gaps; anaerobic products should not be processed in equipment with active metal internals or bronze bearings because contact with metal salts in the absence of air can initiate gelation.
In marine topcoat systems, the acrylic polyol is synthesised with isopropyl methacrylate at 15–25 wt% of total acrylic monomers; replacing isobutyl methacrylate with iPMA at 10 wt% total monomer can shift the calculated Fox-Tg upward by 6–9 °C because the homopolymer glass transition temperature is near 81 °C and the resulting topcoat develops higher hardness without a proportional increase in solution viscosity. Downstream processing for the final coating is a two-component high-solids polyurethane: the acrylic polyol is mixed with hexamethylene diisocyanate trimer or biuret at an NCO:OH ratio of 1.0–1.1:1.0, then applied by airless or air-assisted spray using a 45:1–65:1 pump at dry film thickness of 120–200 µm in 2–3 coats. Pot life at 23 °C is typically 45–60 min; humidity above 75% RH produces carbon dioxide gassing and microfoam in isocyanate cure, and therefore application on marine topsides requires climatic controls. Compliance is demonstrated by laboratory performance under ISO 12944-6:2018 for C4-high and C5-high environments, with ancillary testing under ISO 9227 for salt spray, ISO 6270-1 for condensation resistance, and ISO 4624 for pull-off adhesion. End-product types include topside finishes for coastal and offshore vessels, superstructure coatings, and high-gloss deck finishes where chemical resistance against diesel and hydraulic fluids is required. A known incompatibility is with amine-based additives, which can accelerate isocyanate consumption and reduce pot life or cause premature gelation in the mixed coating.
When coil-coating lines operate at 60–120 m/min, the solution acrylic or polyester-melamine binder must exhibit stable high-shear viscosity at 40–60 wt% solids; isopropyl methacrylate is copolymerised into the acrylic segment to achieve this while reducing peak metal temperature blocking. Formulation addition ratio in coil coating primer and backing coats is typically 5–15 wt% based on total acrylic monomers, with higher levels reserved for primers that require rapid hardness development and low tack after a short dwell. Production involves reverse roller coating of chromate or chrome-free pretreated galvanised steel or aluminium, followed by oven curing at peak metal temperature 220–250 °C for 20–40 s. The glass transition increase contributed by iPMA improves block resistance and reduces dirt pickup in the finished coil stack; however, above 15 wt%, the cured film may become too hard for post-formed profiles and microcracking can occur on tight bend radii. Compliance for pre-painted architectural aluminium and steel includes the EN 13523-25:2014 humidity resistance method, EN 13523-10 UV fluorescent condensation, and REACH SDS obligations under Regulation (EU) 2020/878. End-product types include exterior roof and wall cladding panels, rainware profiles, and appliance wrapper stock. Process limitations include the need to control monomer composition during resin synthesis to avoid excessive solution viscosity at 40 °C after dilution; batch-to-batch variation in iPMA copolymerisation can cause fluctuation in reverse roll pickup and dry film thickness.
Solvent-borne flexographic and gravure printing inks for high-speed packaging applications require acrylic binders with low solution viscosity, narrow molecular weight distribution, and high residual solvent release. In such binder synthesis, iPMA is dosed at 5–20 wt% of total acrylic monomers to raise resin glass transition temperature and reduce tack of the final ink film; this substitution is used where n-butyl methacrylate gives inadequate blocking resistance on rewind and where aromatics-free diluents are required. The ink manufacturing process includes binder synthesis by solution polymerisation in ethyl acetate or n-propanol at 75–100 °C, followed by high-speed disperser premix of pigment and dispersant, bead milling to a grind fineness of 5–15 µm, and letdown with additional binder, solvent, and wax additives. Printing presses run at 150–300 m/min for flexographic or 200–400 m/min for gravure, with oven drying at 60–90 °C; residual solvent in printed film must fall below the converter’s retention specification before lamination. Compliance for packaging inks intended for indirect food contact includes Article 3 of Regulation (EU) 1935/2004, good manufacturing practice under Commission Regulation (EC) 2023/2006, and where applicable, Swiss Ordinance SR 817.023.41 Annex 10 for printing inks. End-product types include shrink sleeves, labels, surface-print films, and lamination films for food and non-food packaging. Trustworthiness boundary: published data specific to this iPMA substitution in high-speed lamination is limited, and migration testing must be conducted on the finished printed structure because residual monomer and low-molecular-weight oligomers may migrate through film under extended storage conditions.
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Isopropyl methacrylate is a clear, low-viscosity methacrylate ester monomer supplied under CAS 4655-34-9 and chemical name propan-2-yl 2-methylprop-2-enoate. It is not commonly marketed under a proprietary model number; the product is specified as an inhibited high-purity bulk monomer. The molecular formula is C7H12O2, the molar mass is 128.17 g/mol, and the ester oxygen is attached to a secondary propyl group. Commercial specifications include minimum ester purity of 99.0% by gas chromatography, water content not exceeding 0.05% by ASTM E1064, color maximum of 10 APHA by ASTM D1209, and monomethyl ether hydroquinone inhibitor concentration between 50 ppm and 100 ppm. Density is controlled between 0.884 g/cm³ and 0.889 g/cm³ at 20 °C by ASTM D4052; the boiling range is 124 °C to 127 °C at 101.3 kPa by ASTM D1078; and the refractive index at 20 °C is specified between 1.410 and 1.415 by ASTM D1218.
The branched isopropyl ester has a different free-volume contribution compared with linear propyl or butyl methacrylates. High-molecular-weight homopolymer glass transition values reported by differential scanning calorimetry under ASTM E1356 are near 81 °C for poly(isopropyl methacrylate), 35 °C for poly(n-propyl methacrylate), 105 °C for poly(methyl methacrylate), and 20 °C for poly(n-butyl methacrylate). The secondary propyl group restricts backbone rotation more than the linear n-propyl group, but the shorter carbon chain does not introduce the internal plasticization characteristic of long linear alkyl esters. In copolymer design, this places isopropyl methacrylate between hard methyl methacrylate and flexible n-butyl methacrylate.
In high-solids solventborne acrylic polyol manufacture, isopropyl methacrylate is typically fed as a comonomer at 15 wt% to 30 wt% of total monomer. The monomer mix is metered into a jacketed stainless steel 316 reactor over 3 h to 4 h while the batch is held at 120 °C to 140 °C. Peroxide initiator is added at 0.5 wt% to 1.5 wt% of total monomer, and agitation is maintained with a pitched-blade or anchor agitator at 80 rpm to 120 rpm. When isopropyl methacrylate replaces n-butyl methacrylate, the higher glass transition of the isopropyl methacrylate homopolymer raises resin hardness and may reduce film tack. The boiling point of isopropyl methacrylate is approximately 25 °C higher than methyl methacrylate, so less monomer is lost through the reflux condenser during atmospheric polymerization.
| Monomer | Normal boiling range (°C) | Homopolymer Tg (°C) | Typical performance contribution |
|---|---|---|---|
| Methyl methacrylate | 100–101 | 105 | Hardness, exterior durability, high Tg |
| Ethyl methacrylate | 117–119 | 65 | Intermediate hardness, lower volatility than methyl methacrylate |
| Isopropyl methacrylate | 124–127 | 81 | Hardness without high evaporation rate |
| n-Butyl methacrylate | 160–163 | 20 | Flexibility, low-Tg modification |
| 2-Ethylhexyl methacrylate | 210–215 | -10 | Low-temperature flexibility, plasticization |
Values are representative reported ranges from polymer science literature for high-molecular-weight homopolymers, not product specifications. Glass transitions are by differential scanning calorimetry at 10 °C/min under ASTM E1356; boiling points are normal atmospheric ranges.
The heat of polymerization of methacrylate ester double bonds is approximately 55–58 kJ/mol. The cooling system for bulk or solution polymerization is specified from this enthalpy, not from total monomer mass alone. Jacket temperature is typically set 10–15 °C below batch temperature during the monomer feed, and a reflux condenser is used to remove latent heat from vaporized monomer or solvent. If batch temperature rises above 150 °C, methacrylate polymerization can enter autoacceleration; the resulting viscosity increase reduces heat-transfer capacity and may create gel. A production mitigation is to stop monomer feed and increase inhibitor addition until the exotherm is controlled. Batch-to-batch variation in MEHQ concentration at the upper specification limit can extend the induction period by 15–30 min depending on initiator type and temperature.
Emulsion polymerization using isopropyl methacrylate requires a stable pre-emulsion because the monomer has low water solubility. The monomer is dispersed with an anionic surfactant at 2–4 wt% based on monomer and passed through a high-shear mixer at 500–1,000 rpm until the droplet size is below 500 nm. If the pre-emulsion is not stable, monomer droplets can coalesce in the feed line and cause reactor composition drift. The latex particle Tg is measured by DSC under ASTM E1356 after film formation, and residual monomer is reduced by post-polymerization redox initiator addition.
The product is stabilized with monomethyl ether hydroquinone, an aerobic inhibitor that requires dissolved oxygen to regenerate. Storage vessels are therefore not inerted with nitrogen unless the stabilizer package is specifically reformulated; common practice is to maintain a conservation vent and avoid oxygen-deficient blanketing. Bulk monomer is stored at temperatures below 35 °C, and heating above 40 °C accelerates inhibitor depletion and may generate initiator species from trace peroxides. A 12-month shelf life is typically assigned when the monomer is held in stainless steel 304 or 316 tanks under these conditions. Moisture ingress above 0.05% is controlled by desiccant breathers on tank vents, because water accelerates ester hydrolysis to methacrylic acid and isopropanol during extended hot storage.
During transfer from bulk containers, sealless pumps with PTFE or carbon mechanical seals are preferred. Polymer formation behind seal faces is a known failure mode when inhibitor concentration drops below 30 ppm; flush lines are therefore left filled with inhibited monomer or solvent between campaigns. If inert gas padding is used during transfer, the oxygen concentration should not fall below 5 vol%; otherwise the MEHQ inhibitor loses effectiveness. Inhibitor-removal columns contain activated alumina or a crosslinked resin and are operated just before reaction at 20–30 °C. Monomer stripped of MEHQ should be used within 24 h and held below 5 °C; storage after inhibitor removal is not recommended because bulk thermal polymerization can begin without an induction period.
When isopropyl methacrylate replaces n-butyl methacrylate in solventborne industrial coatings, the primary formulation change is not solvent adjustment but polymer Tg and hardness. A resin made with 25 wt% isopropyl methacrylate and 20 wt% n-butyl methacrylate in a hydroxy-functional acrylic is typically crosslinked with hexamethylene diisocyanate trimer at an NCO:OH ratio of 1.02:1 to 1.10:1. Hardness measured under ASTM D3363 increases by approximately one pencil grade relative to the n-butyl methacrylate control, and methyl ethyl ketone double rub resistance under ASTM D5402 generally improves by 20–40 double rubs. The improvement is not universal; if the formulation already contains high levels of methyl methacrylate or styrene, the incremental hardness from isopropyl methacrylate is smaller.
In pressure-sensitive adhesive copolymers, isopropyl methacrylate is not used as the dominant monomer because its high Tg reduces peel adhesion. It is instead added at 5 wt% to 15 wt% with 2-ethylhexyl acrylate or n-butyl acrylate to raise shear holding power. Loop tack and peel adhesion are measured under ASTM D6195 and ASTM D3330; a formulation change may increase shear resistance as measured by shear adhesion failure temperature under ASTM D4498 while decreasing 180° peel. The balance depends on polymer gel content and crosslinker type in the hot-melt or solution adhesive.
For UV-curable systems, isopropyl methacrylate is seldom used alone because monofunctional methacrylates cure more slowly than acrylate diluents. Published data for the use of isopropyl methacrylate in cationic photopolymerization is limited; formulations requiring lower shrinkage and moderate hardness may blend isopropyl methacrylate with trimethylolpropane trimethacrylate at 10 wt% to 30 wt%. Cure is monitored by the disappearance of the methacrylate C=C absorbance at 1635 cm⁻¹ or 810 cm⁻¹. Amine-based synergists must not be added to unstabilized isopropyl methacrylate unless aza-Michael addition is intentional, because primary and secondary amines can consume the double bond at ambient temperature.
| Property | Typical limit | Test method |
|---|---|---|
| Ester purity | ≥ 99.0% | Gas chromatography, area normalization |
| Water | ≤ 0.05% | ASTM E1064 |
| Color | ≤ 10 APHA | ASTM D1209 |
| Density at 20 °C | 0.884–0.889 g/cm³ | ASTM D4052 |
| Boiling range | 124–127 °C | ASTM D1078 |
| Refractive index at 20 °C | 1.410–1.415 | ASTM D1218 |
| Acidity as methacrylic acid | ≤ 0.05 wt% | ASTM D1613 |
| Inhibitor as MEHQ | 50–100 ppm | UV/Vis or HPLC |
In thermal polymerization, residual isopropyl methacrylate is monitored by gas chromatography after the monomer feed is complete. A typical resin cook is considered complete when residual isopropyl methacrylate is below 0.5 wt% in a 70% solids resin; the batch is then cooled to 80 °C and re-inhibited with 10–20 ppm MEHQ before storage. The residual level matters because unreacted isopropyl methacrylate can slowly volatilize from baked coatings and contribute to odor or cook-loss. In UV-cured applications, residual monomer is controlled by irradiation dose rather than thermal residence time; the process limit is therefore established by Fourier transform infrared conversion rather than by a resin cook time.
