| HS Code | 669662 |
| Product Category | Electronic Pastes |
| Base Material | Metal, ceramic, or polymer-based composite |
| Functional Phase | Conductive, resistive, or dielectric particles |
| Binder Vehicle | Organic resin, solvent, and additives |
| Appearance | Viscous paste, typically gray, silver, or dark colored |
| Viscosity | Broad range, typically 10,000–200,000 cP at 25°C |
| Particle Size Range | 0.5–50 micrometers depending on grade |
| Solids Content | 70–90 wt% |
| Density | 2.5–7.0 g/cm³ depending on composition |
| Storage Temperature | 2–10°C (refrigerated, sealed) |
| Shelf Life | 3–12 months from manufacturing date |
| Processing Temperature | Curing/sintering temperature typically 150–850°C |
| Electrical Resistivity | 10⁻⁶–10⁻³ ohm·cm after processing |
| Thermal Conductivity | 0.5–10 W/m·K after processing |
| Application Method | Screen printing, stencil printing, or dispensing |
As an accredited Electronic Pastes factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in 1 kg sealed containers, Electronic Pastes packaging ensures safe handling, prevents contamination, and preserves paste quality. |
| Container Loading (20′ FCL) | Electronic Pastes loaded in a 20′ FCL, securely packed in drums/cartons, palletized, braced, and protected to ensure safe transit. |
| Shipping | Electronic Pastes require careful shipping due to their chemical and flammable nature. Pack in sealed, leak-proof containers with inert liners. Use compliant hazardous-material packaging and labeling. Store away from heat, moisture, and ignition sources. Transport via ground or air in accordance with IATA/IMDG regulations, with full documentation and safety data sheets. |
| Storage | Store electronic pastes in a cool, dry, well-ventilated area, tightly sealed in original containers. Maintain temperatures typically between 2–10°C (36–50°F) unless specified otherwise, avoiding freezing and direct sunlight. Keep away from incompatible materials, moisture, and open flames. Monitor shelf life and rotate stock; always follow the manufacturer’s Safety Data Sheet. |
| Shelf Life | Shelf life is typically 6–12 months when stored unopened at recommended temperatures, ensuring optimal viscosity and performance. |
Screen-printed front-side silver pastes for passivated emitter and rear cell and tunnel oxide passivated contact architectures are processed through a six-zone infrared belt furnace where peak wafer temperature is held within a ±5 °C band around 780–830 °C for 1–3 s. The paste supplied for high-temperature firing contains 86–91 wt% silver powder, 2–4 wt% Pb-free glass frit, 6–10 wt% organic vehicle, and 0.5–1.5 wt% rheology modifiers; these proportions produce a wet print thickness of 20–28 µm through a 360-mesh stainless-steel screen with 10–15 µm emulsion, yielding a post-firing finger width of 30–45 µm. Organic vehicle burnout must complete before 500 °C; residual carbon above 0.05 wt% after firing raises series resistance. Overfiring beyond 835 °C causes molten glass to penetrate the emitter and shunt the junction, while underfiring below 750 °C leaves a continuous glass layer between silver crystallites and silicon, elevating transfer-length-method contact resistivity above 2 mΩ·cm². Production-scale belt furnaces with 6–8 zones typically run at belt speeds of 600–750 mm/min and maintain a post-peak cooling gradient of 20–40 °C/s, with rear-side aluminium back-surface field co-fired in the same pass. Finished modules are qualified under IEC 61215-1:2021 MQT 11 thermal cycling and MQT 13 damp heat with <5% maximum power degradation, while paste metal loads are documented under REACH 1907/2006 Article 33 and EU RoHS 2011/65/EU maximum concentration thresholds. Terminal finished product types include PERC and n-TOPCon utility modules, commercial rooftop panels, and building-integrated photovoltaic laminates.
At processing temperatures above 220 °C, amorphous silicon passivation layers in silicon heterojunction cells lose hydrogen and increase surface recombination, so low-temperature silver pastes are printed and cured rather than fired. The paste is applied to transparent conductive oxide layers with sheet resistance 30–70 Ω/□ through 430-mesh screens at a wet film thickness of 20–30 µm; the supplied formulation contains 88–92 wt% silver powder, 1–3 wt% thermoplastic or epoxy binder, 5–8 wt% solvent, and 0.5–2 wt% wetting agent. Curing in a multi-zone convection oven at 180–220 °C for 10–30 min yields volume resistivity 3–6 µΩ·cm and transfer-length-method contact resistivity 1–5 mΩ·cm². Low-temperature-cured grids are processed at line widths of 36–45 µm, and the absence of high-temperature glass frit reduces but does not eliminate moisture-ingress risk at the TCO-paste interface. Finished HJT modules are qualified to IEC 61215-1:2021 and IEC 60904-1:2020, with materials compliance under RoHS 2011/65/EU and REACH 1907/2006. Terminal products include HJT rooftop modules, agrivoltaic glazing, and utility-scale panels; published data for TCO-specific adhesion after damp heat remains limited because TCO surface treatments differ among cell manufacturers.
| Parameter | PERC/TOPCon front-side paste | HJT low-temperature paste |
|---|---|---|
| Processing type | IR belt firing | Convection cure |
| Peak processing temperature | 780–830 °C | 180–220 °C |
| Silver content in as-received paste | 86–91 wt% | 88–92 wt% |
| Wet print thickness | 20–28 µm | 20–30 µm |
| Post-process line width | 30–45 µm | 36–45 µm |
| Volume resistivity | 2–4 µΩ·cm | 3–6 µΩ·cm |
| Contact resistivity by TLM | 0.5–2 mΩ·cm² | 1–5 mΩ·cm² |
Rear-window defroster grids are printed on soda-lime float glass before the bending and tempering cycle, where the paste must develop adhesion and electrical continuity during glass forming at 600–720 °C for 2–5 min. The wet paste contains 70–85 wt% silver powder and 5–15 wt% glass frit in a screen-print vehicle; after firing in the glass tempering furnace, the fired line width is 0.5–1.0 mm, fired thickness 8–15 µm, and sheet resistance 3–8 mΩ/□. Production printing uses 180–230 mesh polyester or stainless-steel screens, followed by hot-air drying at 150–200 °C and co-firing during glass sag-bending. Terminal products include heated rear windows, integrated radio antennas, and rear-window defogger elements with busbar tabs. Compliance is divided between the finished glazing and the raw paste: ECE R43 and FMVSS 205 govern glazing approval, while raw paste heavy-metal content is assessed under REACH 1907/2006 Article 33 and ELV 2000/53/EC Annex II. OEM-specific thermal shock and electrical continuity tests are commonly used because standardized paste-specific adhesion data after 85 °C/85% RH exposure is limited.
In X7R multilayer ceramic capacitor production, internal electrode pastes must match the densification shrinkage of BaTiO₃-based green tape throughout co-firing, otherwise delamination and residual carbon appear at layer interfaces. Nickel powder with D50 0.1–0.3 µm and specific surface area 2.5–5.0 m²/g is dispersed at 45–58 wt% in ethyl cellulose and terpineol; ceramic co-dispersant is added at 3–8 wt% to suppress Ni particle agglomeration. The green dielectric tape is 5–10 µm, the wet electrode print thickness is 0.5–2.0 µm, and after firing the internal electrode thickness is 0.6–1.2 µm. Debinding occurs at 280–400 °C under N₂ with 10–50 ppm O₂, followed by sintering at 1150–1300 °C under pO₂ 10⁻⁹–10⁻⁷ atm; a post-fire reoxidation step at 700–900 °C restores dielectric insulation resistance. Copper termination paste is then dipped and fired at 700–800 °C in N₂, and nickel/tin plating is applied by electrodeposition. Compliance includes IEC 60384-1:2016, AEC-Q200 Rev D stress tests for automotive passives, and IATF 16949:2016. Terminal finished product types are 01005, 0201, 0402, 0603, 0805, and 1206 MLCCs used in smartphones, automotive engine control units, server power distribution, and medical imaging modules.
Conductor pastes for thick-film hybrid circuits are printed on 96% Al₂O₃ substrates and fired in belt furnaces at 850 ± 10 °C for 10–15 min at peak. The as-received paste contains 60–75 wt% silver, 10–15 wt% palladium, 3–7 wt% glass frit, and 8–12 wt% organic vehicle; after firing, line width is 100–150 µm and sheet resistance 15–30 mΩ/□. Wire bonding with 25 µm aluminium wire under MIL-STD-883 Method 2011.5 requires pull strength above 3 gf, and assembled solder joints are inspected to IPC-A-610 Class 3. Compliance for the complete hybrid circuit is maintained under MIL-PRF-38534, with automotive variants additionally certified under IATF 16949:2016. Terminal products include engine control modules, anti-lock brake system sensors, aerospace hybrid microcircuits, and implantable medical device substrates. In long-duration thermal storage at 150 °C for 10,000 h, conductor drift remains below 0.5% when palladium content is maintained above 12 wt%; lower-palladium formulations show silver migration failure under humid bias and should not be used for wire-bonded circuits where humid-bias silver migration cannot be tolerated.
| Downstream application | Primary standard | Test method or clause | Typical acceptance criterion |
|---|---|---|---|
| c-Si photovoltaic module | IEC 61215-1:2021 | MQT 11 thermal cycling, MQT 13 damp heat | <5% power decay at 1000 h damp heat |
| HJT module | IEC 61215-1:2021 | MQT 11, MQT 13 | <5% power decay |
| Automotive heated rear window | ECE R43, FMVSS 205 | OEM thermal shock and electrical continuity | No grid open circuit after 500 cycles |
| MLCC | IEC 60384-1:2016, AEC-Q200 Rev D | Temperature cycling -55/125 °C | Capacitance shift within class tolerance, no delamination |
| Thick-film hybrid circuit | MIL-PRF-38534, MIL-STD-883 Method 2011.5 | Wire bond pull | Pull strength >3 gf for 25 µm Al wire |
| Membrane switch | ASTM D3359-17, ASTM D257 | Cross-cut adhesion, insulation resistance | Classification 4B minimum |
Roll-to-roll printing of silver-polymer pastes for membrane switches and printed biosensor electrodes uses rotary screen mesh 180–250 count on 75–125 µm polyester film. The wet formulation contains 60–75 wt% silver flake, 8–15 wt% polyester or vinyl binder, 10–20 wt% solvent, and 1–3 wt% carbon additive; viscosity at 10 s⁻¹ is 25–50 Pa·s. Curing at 120–150 °C for 5–10 min produces a dry film thickness of 20–30 µm and sheet resistance 15–30 mΩ/□. Adhesion to polyester is tested by ASTM D3359-17 cross-cut classification, with 4B or 5B required for die-cut keypads, and insulation resistance is measured according to ASTM D257. Regulatory compliance is maintained under RoHS 2011/65/EU and REACH 1907/2006. Terminal finished product types include membrane keypads, medical control panels, printed capacitive touch sensors, and single-use ECG electrode traces.
Competitive Electronic Pastes prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8618136850665 or mail to admin@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8618136850665
Email: admin@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
The Electronic Pastes EP-series system is specified as a screen-printable, syringe-dispensable, and jet-dispensable thick-film metallization medium for thick-film hybrid circuits, printed electronics, and photovoltaic metallization. The product family comprises EP-1200 high-solids silver conductive paste, EP-2100 silver-palladium alloy paste, EP-3000 low-temperature-cure silver flake paste, and EP-4100 carbon polymer thick film paste. Each grade is controlled for solids content, particle size distribution, rheological profile, dry-film volume resistivity, and post-cure adhesion to 96% alumina, FR-4, PET, glass, and indium tin oxide-coated substrates. Production qualification lots are evaluated under ASTM D257-14 for electrical volume resistivity, ASTM D4287-00 for high-shear viscosity, and ASTM D4541-17 for pull-off adhesion.
High-solids grades contain silver flake with a D50 between 4 µm and 7 µm, a maximum oversize fraction below 25 µm, and glass frit or oxide adhesion promoters. The solvent package is a glycol ether–terpineol blend adjusted to a flash point above 100°C. The thixotropic index measured at 1 s⁻¹ and 10 s⁻¹ is maintained between 4.0 and 6.0 for screen-print edge definition. EP-1200 is formulated with 82–88 wt% silver flake, 8–12 wt% resin, and 1–3 wt% rheological additives. The absence of lead, cadmium, mercury, and hexavalent chromium is verified by X-ray fluorescence screening according to RoHS 2011/65/EU as amended by (EU) 2015/863.
SAC305 solder paste forms a metallic joint through reflow at 235–245°C, producing Cu₆Sn₅ and Cu₃Sn intermetallic layers with a bulk electrical volume resistivity near 1.7 × 10⁻⁵ Ω·cm. EP-1200 silver paste forms a polymer-bound silver flake network after solvent evaporation and thermoset cure, with a volume resistivity of ≤ 5 × 10⁻⁵ Ω·cm. The selection boundary is thermal budget and substrate compatibility: EP-1200 cures at 150°C for 30 min or 200°C for 10 min, which permits use on epoxy laminate and pre-mounted components that cannot tolerate SAC305 reflow temperatures. Solder paste provides higher current-carrying capacity and lower interconnect resistance, whereas EP-1200 provides low-temperature processing, high adhesion to ceramic, and compatibility with additive printed circuit fabrication.
| Grade | Conductive phase | Processing condition | Volume resistivity | Adhesion or joint shear strength |
|---|---|---|---|---|
| EP-1200 | Silver flake | 150°C/30 min or 200°C/10 min | ≤ 5 × 10⁻⁵ Ω·cm | ≥ 12 MPa on 96% Al₂O₃ |
| EP-2100 | Ag/Pd 90:10 to 85:15 | 850°C/10 min peak firing | ≤ 2.5 × 10⁻⁵ Ω·cm | ≥ 18 MPa on 96% Al₂O₃ |
| EP-3000 | Silver flake | 80°C/30 min or 120°C/10 min | ≤ 2 × 10⁻⁴ Ω·cm | ≥ 6 MPa on PET, 5B crosshatch |
| EP-4100 | Graphite/carbon black | 120°C/15 min | Sheet resistance 10–25 Ω/sq/mil | ≥ 5 MPa on FR-4 |
| SAC305 reference | SnAgCu alloy | Reflow 235–245°C peak | ≈ 1.7 × 10⁻⁵ Ω·cm | Joint shear 25–35 MPa |
On semi-automatic flatbed screen printers equipped with 230–325 mesh polyester or stainless-steel screens, EP-1200 is printed at squeegee speeds of 60–150 mm/s, snap-off distances of 0.5–1.5 mm, and flood-bar pressure below 0.2 MPa. Printed film thickness after levelling is 12–25 µm. For fine-pitch tracks down to 100 µm line width, a 325 mesh screen with 20–25 µm emulsion thickness is specified. The paste is held at 20–25°C and 40–60% relative humidity during printing; longer screen residence times above 8 h produce viscosity drift from solvent evaporation and require adjustment with the manufacturer-approved diluent. Replenishment from sealed containers rather than open screen reservoirs reduces batch-to-batch viscosity variation on production lines.
Convection cure of EP-1200 requires a two-stage ramp. The printed substrate is held at 80°C for 10 min to evaporate residual solvent before the temperature is raised at 2–4°C/min to 150°C for 30 min. Ramp rates above 5°C/min cause solvent boiling, film blistering, and localized resistivity defects. Oxygen-containing atmospheres are preferred because the epoxy crosslinking reaction reaches full conversion above 90°C. Substrates with absorbed moisture above 60% RH should be pre-baked at 120°C for 2 h to prevent steam evolution at the paste-substrate interface. The cured film is inspected for thickness uniformity by contact profilometry and for electrical continuity by four-wire resistance measurement.
EP-2100 is formulated as a glass-frit-bonded thick-film paste with silver-palladium conductive phase ratios of 90:10, 85:15, and 75:25. The palladium addition suppresses silver ion migration under direct-current bias in humid conditions. Accelerated electrochemical migration testing per IPC-TM-650 2.6.14.1 at 85°C, 85% RH, and 5 V DC shows no dendritic growth after 500 h for the 85:15 ratio. The same test on pure silver EP-1200 typically exhibits dendritic growth at 250–350 h under identical bias. The 85:15 grade is therefore specified for multilayer hybrid circuits, chip resistors, and automotive sensor elements where bias-humidity conditions are severe. The higher palladium content of 75:25 increases leach resistance during subsequent soldering but raises sheet resistivity to 45–55 mΩ/sq/mil, compared with 25–35 mΩ/sq/mil for 90:10.
For polyethylene terephthalate and indium tin oxide-coated substrates, EP-3000 is selected because the onset of electrical network formation begins at 70°C during solvent removal, and full cure is reached at 80°C for 30 min. The paste uses a lower-molecular-weight silver flake with D50 3–5 µm and a modified acrylic-urethane binder. After cure, the film exhibits a volume resistivity of ≤ 2 × 10⁻⁴ Ω·cm, a sheet resistance of ≤ 30 mΩ/sq/mil, and no visible cracking after 10 cycles of ±5 mm mandrel bend. The lower cure temperature prevents substrate deformation and indium tin oxide degradation. EP-3000 is not specified for high-power or soldering applications because thermal excursions above 150°C initiate binder degradation and adhesion loss.
EP-4100 carbon polymer thick film paste is formulated with graphite and carbon black dispersed in a phenolic-modified resin. It is screen-printed to a wet film thickness of 15–25 µm and cured at 120°C for 15 min. The cured film has a sheet resistance of 10–25 Ω/sq/mil, which is 3–4 orders of magnitude higher than EP-1200 silver paste but sufficient for membrane touch switch traces, printed resistors, and jumpers where current is below 50 mA. The carbon system eliminates silver migration, withstands flexural fatigue, and is lower in raw-material cost. In high-current traces, the resistive heating of EP-4100 becomes significant: a 0.5 mm-wide trace carrying 100 mA dissipates 0.8–1.5 W/m under typical cured-film thickness, producing local temperature rise above 60°C. Published data for EP-4100 in power-dissipating applications above 0.25 W per trace are limited, and silver or AgPd systems are preferred for those circuits.
For automated dispensing, EP-1200 and EP-3000 are supplied in 10 cc, 30 cc, and 55 cc syringes compatible with auger, piston, and jet valves. Jet dispensing requires a paste with a thixotropic index above 4.5 and a maximum oversize particle fraction below 10 µm to prevent nozzle clogging. Needle diameters from 100 µm to 250 µm are used, with shot volumes from 0.1 nL to 5 nL. During continuous dispensing, the paste pot life at 25°C is 24 h; after this period, viscosity increases by 20–30% and wetting on nickel-gold pads degrades.
Unopened containers are stored at −40°C ± 5°C for a shelf life of 6 months for EP-1200 and EP-3000, and 12 months for EP-2100 refractory paste. Before use, syringes must be equilibrated to 20–25°C for 4 h to prevent condensation. Repeated freeze-thaw cycles are limited to 3; additional cycles increase particle agglomeration and screen clogging. EP-4100 carbon paste is stored at 5°C ± 3°C for 6 months. Opened containers should be purged with dry nitrogen and sealed within 30 min to avoid solvent uptake or moisture ingress.
The epoxy-based EP-1200 is incompatible with amine-functional adhesion promoters, imidazole accelerators, and BF₃-catalyzed hardeners, which can cause premature crosslinking and increase viscosity during printing. For substrate adhesion promotion, silane coupling agents based on glycidoxypropyltrimethoxysilane are specified at 0.1–0.5 wt%. Contact with acetone, methyl ethyl ketone, or ethyl acetate cleaning solvents before cure softens the dried film; ethanol or isopropanol are used for immediate stencil cleaning. EP-2100 high-fired paste is not compatible with low-temperature co-fired ceramic systems that shrink above 12% at 850°C, because the fired film can develop microcracks if the substrate shrinkage rate exceeds 0.5%/min.
| Property | Test standard | Equipment/condition | Acceptance criterion |
|---|---|---|---|
| Volume resistivity | ASTM D257-14 | Four-wire, 25°C | EP-1200: ≤ 5 × 10⁻⁵ Ω·cm |
| Viscosity | ASTM D4287-00 | Cone/plate, 10 s⁻¹, 25°C | 25–45 Pa·s for EP-1200 |
| Particle size | ASTM B214-16 | Sieve or laser diffraction | D50 4–7 µm; D100 ≤ 25 µm |
| Adhesion | ASTM D4541-17 | Pull-off, 96% Al₂O₃ | ≥ 12 MPa for EP-1200 |
| Electrochemical migration | IPC-TM-650 2.6.14.1 | 85°C, 85% RH, 5 V DC | No dendrites, 500 h for EP-2100 |
| Restricted substances | RoHS 2011/65/EU, (EU) 2015/863 | XRF screening | Below maximum concentration values |
When EP-2100 is co-fired with 96% alumina substrates in a belt furnace, the peak temperature is held at 850°C for 10 min with a total furnace residence of 45 min. Nitrogen atmosphere is not required; ambient air firing promotes complete burnout of the organic vehicle. Fired film thickness is 8–14 µm. After firing, laser trimming of EP-2100 resistors is performed with a 532 nm laser at 1–3 W, producing trimmed tolerance better than ±0.5%. This scenario represents the highest-temperature application within the EP-series product family and requires furnace profile validation with each new substrate lot because alumina surface roughness varies between 0.2 µm and 0.8 µm Ra.
