Section
| HS Code | 111180 |
| Product Name | Tech-3766 Solvent-Based Quick Defoamer–BYK-066N Alternative |
| Chemical Family | Modified polysiloxane solution in organic solvent |
| Active Matter | Foam-destroying polysiloxane derivatives |
| Appearance | Clear to slightly hazy liquid |
| Color | Pale yellow |
| Odor | Mild organic-solvent odor |
| Solubility | Fully miscible with most organic coating solvents |
| Water Solubility | Insoluble in water |
| Viscosity At 25c | 100–500 mPa·s |
| Density At 20c | 0.90–0.95 g/cm³ |
| Flash Point | Above 61°C |
| Solvent Base | Organic solvent carrier |
| Recommended Dosage | 0.1%–0.5% by weight of total formulation |
| Defoaming Behavior | Provides rapid bubble rupture and quick foam release |
| Compatibility | Compatible with acrylic, epoxy, polyurethane, and alkyd resin systems |
As an accredited Tech-3766 Solvent-Based Quick Defoamer–BYK-066N Alternative factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Available in 25 kg pails and 200 kg drums, this solvent-based quick defoamer is packaged in sealed, sturdy containers for safe handling. |
| Container Loading (20′ FCL) | 20′ FCL container loading of Tech-3766, BYK-066N alternative: secure drums/pails, proper labeling, safe transport, export-ready packaging. Approximately 20 words. |
| Shipping | Tech-3766 ships as a solvent-based, flammable liquid in sealed containers with proper UN labeling. Ground transport only—no air freight. Ensure upright, secure placement away from ignition sources. Compliant with DOT/ADR regulations. Handle with spill containment and provide SDS to carrier. Expedited options available for domestic orders. |
| Storage | Store Tech-3766 in a cool, dry, well-ventilated area away from sunlight, heat, and open flames. Keep the container tightly sealed to prevent evaporation and contamination. Recommended storage temperature: 5–35°C. Avoid contact with strong oxidizers and keep out of reach of unauthorized personnel. Use within shelf life. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored in original, unopened containers under cool, dry conditions. |
In solvent-borne two-component polyurethane clear topcoats for high-gloss kitchen cabinet fronts, Tech-3766 is introduced at a loading of 0.15–0.30 wt% based on total varnish batch weight, following final letdown of the pigment-free polyol millbase with butyl acetate and xylene to a spray viscosity of 18–22 s through a 4 mm ISO 2431:2019 flow cup at 20±0.5°C. The production vessel is a 0.45 m diameter dual-shaft disperser equipped with a Cowles blade operating at 200–300 rpm during additive incorporation; the defoamer is dosed over 15–20 min into a low-shear zone approximately 2–3 impeller diameters below the liquid surface. If the additive is exposed to disperser tip speeds above 12 m/s after incorporation, the quick-break polymer is partially sheared into the polyol phase and the residual microfoam after 24 h storage increases from 0.4 vol% to 1.2 vol% as determined by gas pycnometry. The cured film is sprayed through air-assisted airless guns with a 0.23–0.28 mm tungsten carbide tip at 80–100 bar fluid pressure and a wet film thickness of 80–120 μm. Under these conditions, foam collapse in a 100 mL shake cylinder is observed from an initial surface foam volume of 25 mL to below 5 mL within 30 s. Compliance for the finished cabinet front is assessed against EU Directive 2004/42/EC, Annex II, category j for two-pack reactive performance coatings, with a solvent-borne VOC limit of 500 g/L at stage II, and for furniture intended for children’s use against EN 71-3:2019+A1:2021 migration limits for barium, cadmium, chromium, lead, and mercury. The terminal finished product is a high-gloss two-component polyurethane clear topcoat for interior wooden furniture panels, produced in batch sizes of 800–1,200 kg per mixing vessel.
Tech-3766 is added during letdown of solvent-based flexographic surface inks for corona-treated polyethylene and polypropylene film at 0.05–0.20 wt% of finished ink mass. The letdown vessel is a jacketed stainless-steel tank maintained at 25±2°C, mixed by a 0.20 m pitched-blade turbine at 400–600 rpm for 30–45 min after thinning the nitrocellulose pigment millbase with a blend of ethyl acetate and n-propanol to 16–20 s on a 4 mm ISO 2431:2019 cup. In this sector, foam persistence is primarily driven by the low static surface tension of the ink, measured at 22–26 mN/m by ASTM D1331-14, combined with chambered doctor blade shear at anilox rolls of 80–120 LPI. Residual microfoam deposits along the blade exit and produces pinholing on solid print areas at press speeds of 200–250 m/min on 0.02 mm low-density polyethylene. A modified 100 mL shake cylinder test is used for process release, requiring macrofoam decay to 10 mL or less within 12 s at 20°C. The finished ink is classified under the EuPIA Good Manufacturing Practice for food-contact printing inks and Swiss Ordinance 817.023.21 for non-food-contact surface printing on food packaging; final print migration testing is conducted under Commission Regulation (EU) 10/2011 using worst-case contact area when the printed web is subsequently laminated. The terminal finished product is a surface-printing flexographic polyamide/nitrocellulose ink for snack packaging, wrap-around labels, and shrink sleeves.
In styrene-containing unsaturated polyester topcoats for medium-density fibreboard furniture panels, Tech-3766 is post-added at 0.20–0.50 wt% of total lacquer, calculated before addition of methyl ethyl ketone peroxide catalyst. The addition is made after silica matting agent and paraffin wax have been dispersed in styrene monomer at Cowles tip speeds of 15–18 m/s for 20–25 min, after the batch has been cooled to 28–32°C. The mixing vessel is then run at 300 rpm for 10–15 min using a 0.35 m dissolver blade, and the material is filtered through a 5 μm bag filter. High-shear exposure is limited because filtration and gear pump transfer at 0.8–1.2 bar impose shear rates above 10⁴ s⁻¹; prolonged recycling after defoamer addition has been observed to reduce quick-break efficiency and allow re-entrainment of air during curtain coating. The coating is applied at 200–300 g/m² by reverse roller coater and cures at ambient temperature with a gel time adjusted to 15–20 min. Compliance is reviewed under EU Directive 2004/42/EC, Annex II, category e for varnishes and woodstains, with a solvent-borne limit of 400 g/L at stage II, and gloss retention is checked after 60° specular gloss measurement per ISO 2813:2014. The terminal finished product is a high-build unsaturated polyester clear topcoat for gloss furniture panels, produced in batch sizes of 500–1,000 kg.
Tech-3766 is incorporated into medium-oil alkyd enamels for structural steel and agricultural machinery at 0.10–0.30 wt% of total batch during final letdown, after zinc phosphate and iron oxide pigments have been dispersed in a 0.6 m high-speed dissolver at 12–14 m/s tip speed. The finished enamel is adjusted to 65–75 KU at 23±2°C per ASTM D562, applied by airless spray using a 0.33 mm tip at 140–160 bar, and cured in a forced-air oven at 60°C for 30 min. Corrosion protection is specified under ISO 12944-5:2019 for atmospheric corrosivity category C3 as a single-coat system, with dry film thickness of 60–80 μm measured by ISO 2808:2019. On dip-coating lines, uncontrolled air release causes crater-like pinholes at the sharp edges of welded steel sections after forced drying. The terminal finished product is a single-component industrial alkyd enamel for steel frames, trailers, and stationary agricultural equipment.
In solvent-borne radiation-curable clear coats for folding cartons, Tech-3766 is added at 0.05–0.15 wt% based on total coating after photoinitiator dissolution and before the final reduction with ethyl acetate to a flow time of 25–35 s on a 4 mm ISO 2431:2019 cup at 22±1°C. The production mixer is a stainless-steel vessel with a low-shear anchor agitator run at 150–250 rpm; defoamer addition at higher shear has been observed to raise cured-film haze from 2.5% to 6.0% measured by ASTM D1003-21, correlating with partial emulsification of the additive. The coating is applied to 250–350 g/m² clay-coated paperboard by a three-roll coater at 10–25 m/min and cured under a 200 W/cm medium-pressure mercury lamp at a peak UVA irradiance of 1.2 W/cm². Compliance for the printed and coated carton is assessed under Regulation (EC) No 1935/2004 and Commission Regulation (EU) 10/2011 through worst-case migration testing of the finished food-contact article. The terminal finished product is a UV-cured high-gloss clear coat for folded carton packaging, applied as an alternative to film lamination.
Vacuum deaeration of solvent-based polychloroprene contact adhesives for footwear lamination is performed in a planetary mixer at 200–250 mbar absolute pressure, with Tech-3766 added at 0.10–0.30 wt% of total adhesive before the final vacuum step. The adhesive batch consists of neoprene rubber, alkylphenolic tackifier, magnesium oxide, and a hydrocarbon-ester solvent blend; viscosity is controlled to 3,500–5,500 mPa·s per ASTM D2196-20 using a Brookfield LV viscometer at 12 rpm and 25°C. The additive is incorporated at a rotor speed of 15–20 rpm for 10 min; vacuum is then applied until the residual foam volume observed in the sight glass is below 0.5 vol%. The product is drummed through a 50 μm filter. Flammability classification is determined under CLP Regulation (EC) No 1272/2008 with flash point measured by ASTM D56-21a; solvent vapour concentration during mixing must remain below 25% of the lower explosion limit per the solvent safety datasheet and ATEX workplace assessment. The terminal finished product is a one-component solvent-based polychloroprene adhesive used to bond vulcanized rubber soles to canvas and leather uppers.
Competitive Tech-3766 Solvent-Based Quick Defoamer–BYK-066N Alternative prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Tech-3766 Solvent-Based Quick Defoamer–BYK-066N Alternative is a polyether-modified polysiloxane defoamer supplied as a clear to slightly hazy liquid for solventborne, high-solids, and radiation-curable coating systems. The product is formulated as a process-equivalent replacement for the silicone defoamer BYK-066N in manufacturing sequences where rapid macrofoam collapse, low cratering tendency, and maintained gloss are required. Typical addition levels range from 0.05 wt% to 0.6 wt% on total formulation, depending on vehicle polarity, pigment loading, and application shear. The polysiloxane active substance reduces dynamic surface tension at air–liquid interfaces while controlled incompatibility allows air bubbles to coalesce without forming wetting defects on the substrate. Unlike unmodified dimethylpolysiloxane defoamers, the polyether modification improves incorporation into polar solventborne vehicles and reduces fisheye formation during recoatability testing. The product is supplied with a nominal density of 0.87–0.91 g/cm³ at 20 °C, a Brookfield viscosity of 80–130 mPa·s at 25 °C, and a non-volatile content of 5.5–7.5 wt% by ASTM D2369.
Defoamer persistence in high-solids alkyd-melamine baking enamels is limited by viscosity increase during flash-off and by competitive adsorption on titanium dioxide pigment surfaces. On production-scale coil coating lines using reverse-roller application at line speeds up to 180 m/min, foam accumulates in the coating pan when air is entrained during recirculation and when high-shear transfer rollers introduce microbubbles. Tech-3766 is prediluted at 1:1 by volume with aromatic 100 solvent before addition to 300 L stainless steel mixing vessels to improve metering accuracy and to prevent localized overdosing that appears as craters in the baked film. In a typical recirculating coil bath, foam height decreased from 40 mm to 6 mm within 45 s after addition of 0.25 wt% Tech-3766, with 60° gloss retention of 92% relative to the defoamer-free control; published data for this specific coil configuration is limited.
A split addition of 50% during pigment dispersion and 50% during letdown is recommended for TiO₂-pigmented alkyd enamels. The hydrophobic polysiloxane adsorbs onto pigment surfaces under high-shear dispersion with a Cowles blade tip speed of 15 m/s for 20 min; if all defoamer is added before dispersion, post-letdown foam may persist because the active species is depleted at the interface where macrofoam is generated. Retention of 20° specular gloss is evaluated by ASTM D523 after a 45 µm dry-film drawdown and a 30 s bake at 160 °C peak metal temperature. At 0.7 wt% addition, surface craters become visible in a 100 µm wet-film spiral drawdown; therefore the upper dosing limit for high-gloss alkyd baking enamels is 0.6 wt% unless reformulation with higher polarity solvent is performed.
In continuous coil coating lines operating at 150–200 m/min with 30 s peak metal temperature bake cycles, the flash-off zone is often shorter than 12 s. Air bubbles that survive flash-off expand during the rapid temperature ramp and form pinholes in the cured film. Tech-3766 is dosed at 0.2–0.4 wt% on total formulation into the mill base before the final solvent adjustment. When evaluated in a white polyester coil coating applied by reverse roller coater at 22 µm dry film thickness, pinhole count per square metre in the cured film was maintained below 5 after 3 h of continuous recirculation, compared with 18–25 for a conventional mineral oil defoamer at the same dosage. The comparison was performed using a calibrated optical microscope at 10× magnification according to an internal procedure; no external standard exists for pinhole count in coil films.
The as-supplied specification is controlled within narrow limits to support automated dosing pumps and high-speed dispersion. Batch release includes density, viscosity, non-volatile content, water content, and flash point. Table 1 lists the nominal specification for Tech-3766 alongside the typical range reported for solventborne polysiloxane defoamers used as BYK-066N replacements.
| Property | Test method | Tech-3766 specification | Reference polysiloxane defoamer range |
|---|---|---|---|
| Density at 20 °C | ASTM D1475 | 0.87–0.91 g/cm³ | 0.86–0.92 g/cm³ |
| Brookfield viscosity at 25 °C | ASTM D2196 | 80–130 mPa·s | 60–180 mPa·s |
| Non-volatile content | ASTM D2369 | 5.5–7.5 wt% | 5.0–10.0 wt% |
| Flash point, closed cup | ASTM D56 | >45 °C | >40 °C |
| Water content | ASTM D4017 | <0.1 wt% | <0.2 wt% |
| Appearance | visual | clear to slightly hazy | clear to slightly hazy |
Relative to the reference BYK-066N, the main technical differences are the narrower batch tolerance for active content, the reduced residual cyclosiloxane level, and the formulation of the carrier solvent to maintain pumpability in automated dosing lines. The product does not contain particulate silica; therefore it is less likely to settle or block 50 µm line filters. Compared with mineral oil defoamers, Tech-3766 requires lower dosage to achieve the same foam collapse but has a narrower compatibility window in high-polarity solvent blends. Compared with unmodified dimethylpolysiloxane defoamers, the polyether modification reduces fisheye formation in recoatable topcoats, but it still requires dosage optimization to avoid loss of intercoat adhesion in epoxy primer interlayers.
Storage stability is maintained in sealed containers at 5–35 °C for 24 months from date of manufacture. Freeze-thaw exposure below 0 °C can cause temporary haze or viscosity increase; the product should be allowed to reach 20 °C and gently homogenized before use. The material is hydrophobic and develops phase separation when water contamination exceeds 0.1 wt% as determined by ASTM D4017. Repeated opening of containers without dry nitrogen blanketing is not recommended at relative humidity above 60%. The product is supplied in 25 kg net high-density polyethylene pails and 200 kg steel drums with internal lacquer lining.
Tech-3766 is formulated to comply with EU REACH registration obligations and the RoHS Directive 2011/65/EU Annex II substance restrictions for lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, and polybrominated diphenyl ethers. Residual octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane are controlled below 0.1 wt% each to facilitate EU REACH documentation where Annex XVII restrictions apply. The product has not been evaluated under FDA 21 CFR 175.300 for direct food-contact coatings; formulators must confirm suitability for their specific end use.
In two-component polyurethane wood coatings, air is entrained during mixing of Part A with Part B and during addition of tinting pastes. Tech-3766 is added to the letdown stage at 0.15–0.35 wt% on total mixed formulation to reduce air release time after high-torque mixing with a dispersion blade at 800 rpm for 3 min. The defoamer should not be pre-blended with amine-functional accelerators or zinc octoate catalysts before resin addition because localized high concentration can generate microgel nuclei that later appear as surface seeds. Addition after the curative is dispersed avoids this process failure mode. Pot life is not adversely affected at the recommended dosage when gel time is measured by internal procedure.
When the product is evaluated in a 2K polyurethane clearcoat with 35% solids, a dosage of 0.2 wt% reduced air bubble persistence in a 150 µm wet film from 12 s to 2 s after drawdown. The dried film exhibited no visual haze when measured according to ASTM D1003, with a haze value below 0.8%. Higher addition above 0.4 wt% caused a loss of intercoat adhesion to the subsequent sealer coat, with cross-cut rating falling from 5B to 3B under ASTM D3359. This threshold defines the upper limit for recoatable furniture and millwork systems.
For radiation-curable clear overprint varnishes and UV-curable inkjet primers, Tech-3766 is used at 0.05–0.15 wt% of total formulation because the low formulation viscosity and rapid UV cure allow surface defects to be frozen in before leveling can occur. The product is added after the photoinitiator blend is dissolved and before final viscosity adjustment with tripropylene glycol diacrylate. A high-shear mixing step of 10 min at 1000 rpm is sufficient for incorporation. The defoamer is not recommended for formulations containing more than 5 wt% water, because phase separation produces visible particles in the cured film. Reported 60° gloss values for UV overprint varnish at 0.1 wt% addition were within 2–3 gloss units of the undosed control when measured by ASTM D523. Published data for this specific UV-curable configuration is limited; laboratory drawdown testing is required to confirm interlaminar adhesion with subsequent flexo or offset inks.
In two-component epoxy primer interlayers applied to prepared steel, Tech-3766 has a practical upper limit of 0.6 wt% when overcoating is required. At 0.8 wt%, surface craters appear under cross-flow spray application with a conventional air spray gun at 3.5 bar atomization pressure and 120 µm wet-film thickness. Recoatability testing after 24 h ambient cure at 23 °C and 50% relative humidity showed a one-unit reduction in ASTM D3359 cross-cut adhesion on the subsequent polyurethane topcoat. This performance limit is consistent with the general behavior of polyether-modified polysiloxane defoamers in high-surface-energy primer layers. In dry heat service above 150 °C, volatile siloxane migration from the primer can reduce intercoat adhesion; therefore the product is limited to systems with bake temperatures below 150 °C unless adhesion is revalidated per ISO 2409.
Inline filtration of the formulated coating through 50 µm bag filters does not remove the active polysiloxane because it is soluble or colloidally dispersed in the solvent phase. Filtration of the neat defoamer through 25 µm filters is not required before dosing. If the product is stored at temperatures above 35 °C, viscosity drift may exceed 10%; therefore temperature-controlled dosing loops are specified for production lines in warm climates.
