| HS Code | 253618 |
| Product | Conventional Thermal Conductive Low-temperature Conductive Silver Paste Electronic/EL Grade |
| Thermal Conductivity | 8-12 W/m·K |
| Electrical Resistivity | 2×10^-4 to 5×10^-4 Ω·cm |
| Silver Content | 70-85 wt% |
| Viscosity | 15,000-30,000 mPa·s |
| Curing Temperature | 90-150 °C |
| Curing Time | 10-60 minutes |
| Adhesion Strength | 5-15 N/mm² |
| Particle Size | 1-10 μm |
| Storage Temperature | 2-10 °C |
| Shelf Life | 6 months at 5 °C |
| Work Life | 8 hours at 25 °C |
| Application Method | Screen printing/stencil printing |
As an accredited Conventional Thermal Conductive Low-temperature Conductive Silver Paste Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Supplied in sealed 100g jars, this electronic-grade silver paste ensures stable thermal and electrical conductivity for EL applications. |
| Container Loading (20′ FCL) | 20′ FCL loading of conventional thermal conductive low-temperature silver paste (Electronic/EL grade), packed in drums/pails, palletized and secured. |
| Shipping | This conductive silver paste is shipped in sealed, moisture-resistant containers to preserve viscosity and performance. Keep upright, avoid extreme temperatures, and protect from static discharge. Use proper grounding and PPE during handling. Not classified as dangerous goods under normal conditions, but standard chemical transport precautions apply. |
| Storage | Store in a tightly sealed container, away from sunlight, heat, and humidity. Recommended temperature: 5–10°C (refrigerate, do not freeze). Keep upright to prevent settling. Avoid exposure to air to prevent solvent evaporation and contamination. Stir gently before use. Shelf life typically 6 months from manufacture date under proper conditions. |
| Shelf Life | Shelf life is typically 6 months when stored unopened at 2–8°C in original container, avoiding freezing. |
Low-temperature conductive silver paste of Electronic/EL grade functions as the single-component conductive layer in screen-printed polymer thick film circuits where terminal assembly remains solderless because PET and untreated PEN substrates cannot withstand soldering temperatures above 150 °C. The paste is conditioned in a controlled environment at 20–25 °C and 45–55 % RH for 30 min before screen printing through a stainless steel mesh of 230–325 mesh per inch with a solvent-resistant emulsion thickness of 10–24 µm. A polyurethane squeegee of 70–75 Shore A durometer is operated at a 60–70° attack angle and 15–25 mm/s blade speed, yielding a wet film thickness of 15–30 µm. The printed pattern is cured in a forced-air convection oven with chamber uniformity of ±5 °C at 120–130 °C for 8–12 min. Formula addition ratio: the paste is used as supplied at 100 wt% functional solids; when fine-line spacing below 150 µm is printed in ambient humidity above 60 % RH, viscosity is reduced by adding 0.5–3.0 wt% of butyl carbitol acetate thinner under planetary mixing at 150–300 rpm for 3–5 min. The cured conductive trace exhibits sheet resistivity of ≤0.025 Ω/sq at 25 µm dry film thickness measured using a collinear four-point probe per ASTM F390-21. Adhesion to PET is qualified by cross-cut tape testing per ASTM D3359-17 with a 5B rating required after 50 dynamic flex cycles at 0.5 cm bend radius. Industry compliance standards for printed circuit assemblies include RoHS 2011/65/EU Annex II, REACH 1907/2006 SVHC, halogen-free requirements under IEC 61249-2-21, and final assembly cleanliness per IPC-A-610 Class 2. Downstream production involves screen printing, forced-air curing, automated optical inspection for line width deviation below ±20 µm, dielectric overprint, and die-cutting or lamination to pressure-sensitive adhesive carriers. Terminal finished product types include membrane touch switches, capacitive sensor panels, disposable diagnostic test strips, and printed flex tails for consumer electronics. Operational limitation: the paste must not be blended with amine-containing solvent extenders because amine residues accelerate silver migration under bias moisture testing and reduce insulation resistance below 1×10⁹ Ω after 85 °C/85 % RH exposure. Batch-to-batch viscosity variation is controlled within ±15% to maintain wet film thickness within ±3 µm across a 500-sheet flat-bed run.
At single-use biopotential electrode manufacturing lines, low-temperature conductive silver paste of Electronic/EL grade is printed as the conductive base electrode on 75 µm polyethylene terephthalate film or 25–50 µm polyurethane nonwoven laminate. The paste is deposited through a 180–230 mesh per inch stainless steel screen with 10–20 µm emulsion at a wet film thickness of 20–30 µm, then cured in a tunnel oven at 90–110 °C for 8–10 min. The formulation addition ratio for this application is normally 100 wt% supplied paste as the base conductive layer; where silver/silver chloride overprint is required, the base silver layer is snap-cured at 80 °C for 5 min before a 20–40 µm wet Ag/AgCl layer is printed over the designated electrode area. The cured silver layer shows sheet resistivity of ≤0.030 Ω/sq at 20 µm dry film thickness measured per ASTM F390-21 and maintains ≤0.050 Ω/sq after 24 h exposure to 37 °C synthetic perspiration at pH 4.7, evaluated under ISO 10993-5 cytotoxicity and ISO 10993-10 skin irritation protocols. Industry compliance standards for skin-contact devices include ISO 10993-1 biological evaluation, IEC 60601-1 medical electrical equipment safety, risk management under ISO 14971, and disposable electrode performance per ANSI/AAMI EC12. Downstream production process consists of roll-to-roll screen printing, convection drying, dielectric encapsulation, conductive carbon or silver/silver chloride overprinting, rotary die-cutting, and attachment of stainless steel or conductive carbon leads. Terminal finished product types include resting ECG electrode patches, Holter monitor electrodes, transcutaneous electrical nerve stimulation electrodes, and EEG headset sensors. Operational limitation: the cured silver layer must be isolated from direct contact with sulfur-vulcanized elastomer straps because sulfur migration increases electrode polarization and degrades signal quality; published data for this specific configuration is limited.
Post-lamination frequency detuning in high-frequency and ultra-high-frequency smart labels is governed primarily by geometric distortion of the printed antenna pattern and by the silver film’s conductivity after exposure to hot lamination adhesives. Low-temperature silver paste is printed as the antenna population on 50 µm PET film using rotary screen equipment operating at 30–50 m/min, with a cylinder mesh of 250–325 mesh per inch, a 75–80 Shore A squeegee, and mesh tension of 25–30 N/cm. The formulation addition ratio is adapted to line speed: the paste is used at 100 wt% for flat-bed printing, while rotary screen runs add 1.0–2.5 wt% of slow-evaporating retarder to maintain a steady-state viscosity of 20,000–35,000 mPa·s at 25 °C. The wet film thickness is held at 15–25 µm, and the paste is cured in a forced-air tunnel at 120–130 °C for 5–8 min to achieve sheet resistivity of ≤0.020 Ω/sq at 18 µm dry film thickness measured per ASTM F390-21. Industry compliance standards for RFID inlay manufacturing include ISO/IEC 18000-6C for UHF air interface, EPC Class 1 Generation 2 tag protocols, ISO/IEC 14443 for near-field communication transponders, and ISO/IEC 18046-3 for tag performance test methods. Downstream production involves rotary screen printing, hot lamination of paper facestock at 80–100 °C, chip attachment with anisotropic conductive paste, and singulation into individual inlays. Terminal finished product types include apparel hangtags, logistics RFID labels, NFC-enabled marketing tags, and asset tracking inlays. Operational limitation: the paste must not be diluted with volatile ketone solvents because rapid flash-off creates edge slump and changes antenna inductance beyond ±0.5 µH, causing tag frequency response to fall outside reader interrogation bandwidth.
Low-temperature conductive silver paste serves as the electron and hole collection grid in silicon heterojunction cells where amorphous silicon passivation layers degrade if exposed to firing temperatures above 200 °C. Screen printing is performed on textured n-type monocrystalline wafers with a dual-lane printer equipped with 360–430 mesh per inch fine-wire stainless steel screens, 10–15 µm emulsion, and 65–70 Shore A squeegee at speed 250–400 mm/s. The paste is used without binder dilution at 100 wt% formulation addition; viscosity correction by more than 0.5 wt% solvent is generally not recommended because it shifts screen release behavior and reduces fired line height below 20 µm. Wet laydown is controlled by screen opening and finger geometry, commonly between 60 mg and 120 mg per 166 mm wafer side for R&D-scale cells, but published data for this specific configuration is limited. The printed wafer is dried at 60–80 °C for 5–10 min and cured in an infrared/convection belt furnace with peak wafer temperature 170–200 °C for 12–20 min. After cure, contact resistivity measured by transfer length method is typically ≤5 mΩ·cm² on TCO-coated surfaces, while sheet resistivity of the bulk silver line is ≤0.020 Ω/sq at 25 µm dry thickness measured per ASTM F390-21. Industry compliance standards for finished modules include IEC 61215-1:2021 design qualification, IEC 60904-3:2019 spectral response measurement, and RoHS 2011/65/EU Annex II for restricted substances. Downstream production involves surface cleaning, screen printing of front and rear grids, low-temperature drying, belt curing, cell testing under STC 1,000 W/m², stringing, lamination, and module integration. Terminal finished product types include bifacial heterojunction modules, building-integrated photovoltaic glass units, and R&D reference cells. Operational limitation: contact resistance to textured TCO layers is sensitive to cure temperature nonuniformity exceeding ±5 °C across the wafer, which produces finger-to-finger series resistance variation above 15%; full production qualification requires cell-level damp heat validation because IEC 61215 module tests do not guarantee paste-specific performance.
On flat-bed screen-printing lines for automotive lens defogger elements, the low-temperature silver paste is used to form resistive tracks with controlled sheet resistance on 175 µm polyester or 50 µm polyimide film. The paste is printed at 100 wt% supplied viscosity through a 200–275 mesh per inch stainless steel screen with 10–18 µm emulsion, yielding a wet film thickness of 20–30 µm. For high-density serpentine resistor traces with line width below 300 µm, 2.0–3.0 wt% of butyl carbitol acetate is added to reduce viscosity from 30,000–40,000 mPa·s to 18,000–28,000 mPa·s at 25 °C. The printed element is cured at 120–130 °C for 10–12 min in an air convection oven; the cured silver film exhibits sheet resistivity of 0.025–0.040 Ω/sq at 25 µm dry film thickness, and steady-state operating temperature is maintained within ±5 °C of control setpoint by closed-loop pulse-width modulation. Industry compliance standards for this application include ISO 16750-4 climate loads for road vehicle electrical and electronic equipment, RoHS 2011/65/EU Annex II, and flammability classification under UL 94 VTM-2 for the polyester carrier. Downstream production involves screen printing, forced-air curing, overprinting with UV-curable dielectric paste, silver/carbon busbar deposition, lamination with acrylic adhesive, die-cutting, and crimped terminal attachment. Terminal finished product types include exterior mirror defoggers, camera window heaters, battery warming films, seat belt heater strips, and medical warming blankets. Operational limitation: thermal conductivity of the cured silver film is typically 2.0–4.0 W·m⁻¹·K⁻¹ when measured on a bulk cured specimen per ISO 22007-2, but published data for printed films below 30 µm is limited; dry spots or pinholes larger than 50 µm in the silver track create localized hot spots and must be eliminated by 100% backlight inspection before lamination.
Electroluminescent lamp rear electrodes printed with low-temperature silver paste must maintain low sheet resistance after prolonged damp heat exposure because electrode oxidation directly reduces lamp brightness and increases power consumption. The paste is applied as the rear electrode over a barium titanate dielectric layer on 125 µm ITO-sputtered PET using a 230–325 mesh per inch stainless steel screen, a 70 Shore A squeegee, and 15–20 µm wet film thickness. The formulation addition ratio is 100 wt% for standard rear electrode deposition; if open time on the press exceeds 20 min, 0.5–1.5 wt% of high-boiling retarder is added under slow mixing to prevent screen blocking without lowering cured conductivity below 0.030 Ω/sq at 20 µm dry film thickness. Curing is performed in a forced-air oven at 120–130 °C for 5–8 min. Industry compliance standards for EL lamp reliability include IEC 60068-2-67 damp heat steady-state testing at 85 °C/85 % RH, RoHS 2011/65/EU Annex II, and electromagnetic compatibility of the EL driver as a system under IEC 61000-6-3. Downstream production consists of front ITO patterning, phosphor/dielectric screen printing, silver rear electrode deposition, curing, insulating overprint, flex lead attachment, and lamination with desiccant-bearing barrier film. Terminal finished product types include automotive instrument panel backlights, aircraft cockpit night-vision compatible lighting, safety signage, and wearable illuminated patches. Operational limitation: the silver paste must be stored sealed at 5–10 °C and allowed to equilibrate for 2 h before opening above 60 % RH; exposure of uncured paste to sulfur-containing phosphor contaminants produces silver sulfide and increases rear electrode sheet resistance above 0.05 Ω/sq after 1,000 h of damp heat. High-reliability automotive EL lamps commonly specify luminance decay of ≤10% after 1,000 h at 85 °C/85 % RH; programmes requiring ≤5% have been observed for aerospace cockpit lighting, but published data for this specific configuration is limited.
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Designated CT-LE-8200, the Conventional Thermal Conductive Low-temperature Conductive Silver Paste Electronic/EL Grade is supplied as a solvent-borne, screen-printable silver flake suspension with silver content of 80 wt% ± 3 wt% by thermogravimetry per ISO 11358-1. The paste is formulated for printed circuitry and bus-bar structures on indium tin oxide, polyethylene terephthalate, and polycarbonate films where curing above 130 °C is excluded. Under a recommended cure of 120 °C for 15 min in a forced-air convection oven, printed films at 25 µm to 40 µm dry thickness exhibit volume resistivity below 5 × 10⁻⁵ Ω·cm according to ASTM D257; thermal conductivity is reported between 2.5 W·m⁻¹·K⁻¹ and 3.5 W·m⁻¹·K⁻¹ by ASTM E1530. Compliance screening under IEC 62321-5 yields lead and cadmium below 100 ppm in homogeneous silver solids, consistent with RoHS Directive 2011/65/EU Annex II. The Electronic/EL grade differs from general-purpose silver paste through sodium, chloride, and potassium limits that reduce ion-assisted silver migration in electroluminescent lamps, and differs from high-temperature silver sintering pastes because metallic network formation does not require furnace profiles above 800 °C.
Silver flake packing and surface treatment dominate electrical conduction; thermal conductivity, however, depends on densified flake-to-flake contacts and any ceramic filler retained in the dried film. The binder system is selected to shrink during solvent evaporation while remaining below crosslink onset until the final cure zone. A premature cure at 80 °C traps solvent, yielding resistivity above 1 × 10⁻³ Ω·cm on glass test coupons. A staged profile of 60 °C for 10 min, 90 °C for 10 min, and 120 °C for 15 min is used on production lines with infrared/forced-air hybrid ovens because the slow ramp prevents skinning before residual oxygenated solvent is released. The material should not be reflowed above 260 °C because binder decomposition creates outgassing and adhesion loss on ITO surfaces. The low-temperature cure does not produce metallurgical sintering between silver particles; conductivity develops through compaction of silver flakes during binder densification, so the final film remains below bulk silver conductivity and is intended for low-current EL bus electrodes, touch-panel edge traces, and membrane circuit paths.
Comparative thermal conductivity values require identical sample preparation. Films cured on 1.0 mm aluminum with surface roughness Ra < 0.5 µm and tested under 200 kPa contact pressure may produce 3.0 W·m⁻¹·K⁻¹, while the same paste printed on PET can return 1.8 W·m⁻¹·K⁻¹ due to substrate thermal resistance and reduced contact. The ASTM E1530 guarded heat flow method reports through-plane conductivity; transient plane source per ISO 22007-2 may generate different values on the same cured film. Published data for this specific configuration is limited because thermal conductivity of a printed silver film is dominated by interfacial resistance rather than intrinsic silver phase conductivity. Users should generate method-specific values for comparative qualification, particularly when the paste is compared against thermally conductive dielectric pastes or pressure-sensitive graphite pads.
Viscosity at 25 °C using Brookfield CP51 at 10 rpm is 28,000 mPa·s to 38,000 mPa·s; at 1 rpm it increases to 120,000 mPa·s to 150,000 mPa·s, giving a thixotropic index of 4.0 to 5.0 per ASTM D2196. The high low-shear viscosity holds printed pads in place during leveling, while lower high-shear viscosity permits open mesh passage on 325 mesh stainless steel. Batch-to-batch viscosity variation observed on production fill lines is ± 3,000 mPa·s; material above 45,000 mPa·s at 10 rpm causes starved prints on 325 mesh screens with 12 µm emulsion thickness. Solvent evaporation from open containers increases viscosity by 2,000 mPa·s per hour at 23 °C and 50% RH, which is a primary source of first-print and last-print variation in long production runs.
| Property | Measured value | Standard | Condition |
|---|---|---|---|
| Silver content | 80 wt% ± 3 wt% | ISO 11358-1 | Thermogravimetry, nitrogen |
| Brookfield viscosity | 28,000–38,000 mPa·s | ASTM D2196 | CP51, 10 rpm, 25 °C |
| Thixotropic index | 4.0–5.0 | ASTM D2196 | 1 rpm/10 rpm |
| Volume resistivity | ≤ 5 × 10⁻⁵ Ω·cm | ASTM D257 | After 120 °C/15 min, 25–40 µm dry film |
| Thermal conductivity | 2.5–3.5 W·m⁻¹·K⁻¹ | ASTM E1530 | Aluminum substrate, 200 kPa, 25 °C |
| Adhesion | 5B | ASTM D3359 | ITO/glass, cross-cut after cure |
| Sodium/chloride | < 20 ppm / < 30 ppm | IPC-TM-650 2.3.28 | Ion chromatography extract |
On high-volume screen printing lines, the paste is printed through 250 to 325 mesh stainless steel screens with 10 µm to 20 µm photoimageable emulsion. Squeegee durometer is set at 75 Shore A to 80 Shore A, attack angle 45° to 60°, and print speed 40 mm/s to 100 mm/s. Snap-off is maintained between 0.5 mm and 1.0 mm to prevent screen sticking. After wet laydown, a leveling time of 5 min to 10 min at 23 °C ± 2 °C is used before heating. In forced convection ovens, a solvent ramp at 60 °C to 80 °C for 5 min to 10 min prevents skinning. The final cure window is 120 °C ± 5 °C for 15 min to 20 min; at 115 °C the cured film develops residual resistance above 1 × 10⁻⁴ Ω·cm, while at 125 °C to 130 °C on PET substrates the risk of substrate shrinkage increases registration deviation to 0.2 mm across a 300 mm panel. On an automated flatbed printer with 1.2 m print stroke, edge definition remains within ± 30 µm line width when screen tension is maintained at 25 N/cm to 30 N/cm. Production logs show skipped prints increased from 0.3% to 2.1% when screen open area was reduced below 35%; increasing squeegee pressure beyond 300 kPa then damaged 12 µm emulsion and caused paste bleeding into non-print areas.
Low-temperature conductive silver paste in electronic/EL grade is often compared with three adjacent classes: high-temperature sinterable thick film, pressure-assisted nano-silver paste, and silver epoxy adhesive. The key operational difference is the process ceiling: this conventional product cures at 120 °C without external pressure or inert atmosphere. High-temperature sinterable systems require 550 °C to 850 °C belt furnaces and yield volume resistivity near 2 × 10⁻⁶ Ω·cm, but destroy polymer films. Pressure-assisted nano-silver pastes may sinter at 180 °C to 250 °C under 1 MPa to 10 MPa, offering higher die-shear strength but requiring heated press tooling. Silver epoxy adhesives develop conductivity through epoxy crosslinking, typically cure at 150 °C for 30 min, and display volume resistivity in the 1 × 10⁻³ to 1 × 10⁻⁴ Ω·cm range. This paste occupies the low-temperature, no-pressure process slot while still providing thermal conductivity for EL bus-bar applications, although bulk silver thermal conductivity is not approached because the cured film is a polymer-bonded flake network rather than a fully sintered metal matrix.
| Class | Cure/sinter condition | Volume resistivity | Thermal conductivity | Compatible substrates |
|---|---|---|---|---|
| Conventional low-temperature conductive silver paste CT-LE-8200 | 120 °C, 15 min, no pressure | ≤ 5 × 10⁻⁵ Ω·cm | 2.5–3.5 W·m⁻¹·K⁻¹ | PET, PC, ITO glass, FR-4 |
| High-temperature silver thick film | 550–850 °C, 30 min | ≤ 2 × 10⁻⁶ Ω·cm | 50–200 W·m⁻¹·K⁻¹ | Alumina, glass, silicon |
| Pressure-assisted nano-silver | 180–250 °C, 1–10 MPa | ≤ 1 × 10⁻⁵ Ω·cm | 10–100 W·m⁻¹·K⁻¹ | Silicon, DBC, copper |
| Silver epoxy adhesive | 150 °C, 30 min | 1 × 10⁻⁴ to 1 × 10⁻³ Ω·cm | 0.5–2.5 W·m⁻¹·K⁻¹ | PET, PC, metals |
Pot life is governed by solvent retention and shear-induced structure recovery. At 23 °C and 50% RH, the paste remains dispensable through 25-gauge needles for 8 h. At 35 °C, this falls to 3 h; viscosity increase above 60,000 mPa·s produces stringing and tailing in high-speed dispense. On a pneumatic dispense system with 2.5 cm³ cartridges and 0.5 mm needle standoff, tailing defects occurred when viscosity exceeded 60,000 mPa·s, causing string lengths over 200 µm between die pads. Reducing the needle to 27-gauge without lowering pressure increased shear heating; paste temperature rose from 23 °C to 31 °C within 20 min, shortening pot life. Refrigerated storage at 5 °C ± 2 °C extends sealed shelf life to 9 months. Before use, containers must be equilibrated at 23 °C for 4 h without lid removal to prevent moisture condensation. The material should not be thinned with non-approved solvents; the addition of 1% of a fast-evaporating solvent can precipitate silver flake agglomerates and clog 27-gauge needles.
Electroluminescent lamp production prints the product as a rear electrode or bus bar over barium titanate dielectric layers. To avoid dielectric breakdown, the printed silver film should be free of needle or screen-mesh voids greater than 100 µm; a two-pass wet laydown of 35 µm to 45 µm is common, producing dry films of 25 µm to 30 µm after solvent loss. Curing at 120 °C for 15 min produces sheet resistance below 30 mΩ/sq on polyester film. In EL lamps, the rear electrode silver area should not extend within 0.5 mm of the terminal foil edge to reduce silver migration under 100 V AC and 400 Hz. Humidity testing at 60 °C and 85% RH for 500 h with a 10 V DC bias is used to monitor dendritic growth between adjacent traces. The paste is not formulated for high-flex dynamic folding beyond 10,000 cycles at 2 mm bend radius without crack mitigation; silver flake network develops microcracks and resistance can increase by 10× after repeated strain. Performance in direct contact with phosphor layers should be verified for resistive current leakage under 100 V AC and 400 Hz because residual ionic contamination can promote dendritic silver migration across phosphor stacks.
