| HS Code | 238190 |
| Product Name | Polarizer Special Dye Electronic/EL Grade |
| Chemical Family | Organic dichroic dye |
| Appearance | Powder or crystalline solid |
| Color Hue | Broad absorption spectrum (violet to near-infrared depending on type) |
| Purity | ≥ 99.0% (HPLC) |
| Solubility | Soluble in polar organic solvents (e.g., DMF, DMSO, NMP) |
| Dichroic Ratio | High (typically ≥ 10:1 in aligned polymer matrix) |
| Absorption Wavelength | Tunable across visible spectrum (400–700 nm) |
| Thermal Stability | Decomposition temperature ≥ 250 °C |
| Electronic Grade | Low ionic impurities (< 50 ppm Na, K, Fe) |
| El Suitability | Compatible with electroluminescent display fabrication processes |
As an accredited Polarizer Special Dye Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 1 kg sealed, light-resistant foil bags under inert nitrogen, ensuring high-purity Polarizer Special Dye Electronic/EL Grade remains stable. |
| Container Loading (20′ FCL) | Polarizer Special Dye Electronic/EL Grade loaded in 20′ FCL, securely palletized, drums sealed, protected from moisture, heat, sunlight. |
| Shipping | Polarizer Special Dye Electronic/EL Grade ships in sealed, light-resistant containers to prevent contamination and degradation. Transport is via ground freight only, with temperature-controlled conditions advised. Proper hazard labeling, MSDS documentation, and secure upright packaging are required. Ensure compatibility with local regulations before dispatch. |
| Storage | Store Polarizer Special Dye Electronic/EL Grade in a clean, cool, dry, well-ventilated area away from direct sunlight, heat, moisture, and incompatible substances. Keep the container tightly sealed when not in use to prevent contamination and degradation. Use appropriate PPE, avoid dust generation, and maintain strict cleanliness for electronic-grade performance. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored sealed, cool, dry, and protected from light. |
In high-temperature automotive display polarizer film production, electronic-grade polarizer special dye is introduced in the aqueous dyeing stage after polyvinyl alcohol swelling rather than in the raw polymer melt. The dye uptake is controlled by bath concentration, bath temperature, residence time, and the degree of PVA saponification, which is maintained above 99 mol%. In continuous tenter-frame lines with web widths above 1,000 mm and line speeds of 8–18 m/min, the aqueous dye bath is held at 0.3–0.8 g/L; the resulting dye-to-PVA dry-mass ratio in the finished film ranges from 0.4–0.9 wt% depending on downstream stretch ratio. The dyed film is uniaxially stretched 4–6× in boric acid solution maintained at 4–6 wt% and 55–65°C, which fixes the dichroic chromophore orientation along the machine-direction absorption axis and raises mechanical stiffness for subsequent lamination to triacetyl cellulose protective films. Acceptance protocols for this application reference RoHS 2011/65/EU Annex II and the 2015/863 phthalate restrictions, while the electronic-grade designation requires low ionic extractables because residual sodium, potassium, or chloride above supplier limits can form haze nuclei or interact with boric acid at the film edge. Component manufacturing sites are typically audited to IATF 16949:2016 for automotive traceability. The finished polarizer roll stock with pressure-sensitive adhesive is cut and supplied to dashboard cluster, center-stack, and head-up display module lines. Field data from automotive manufacturing environments indicate that iodine-based polarizers can lose polarization efficiency after 85°C/85% RH aging, whereas dye-stuff polarizers trade some initial transmittance for retention of neutral grey coordinates and survival under 105°C storage without iodine sublimation.
| Control area | Standard/method | Typical acceptance criterion |
|---|---|---|
| Restricted substances | RoHS 2011/65/EU Annex II + 2015/863 | Pb ≤ 0.1 wt%, Hg ≤ 0.1 wt%, Cd ≤ 0.01 wt% in homogeneous material |
| SVHC declaration | REACH EC 1907/2006 Article 33 | Declaration required if candidate list substance > 0.1 wt% |
| Halogen content | IEC 61249-2-21:2003 | Cl < 900 ppm, Br < 900 ppm, total < 1500 ppm |
| Haze | ASTM D1003-21 | ≤ 2.0% on finished polarizer stack |
Guest-host liquid crystal display mixtures incorporate polarizer special dye directly into the positive-dielectric nematic host at 1.0–2.0 wt% for transmissive cells and 1.5–3.0 wt% for reflective cells. The integration process uses a vacuum planetary mixer at 25°C for 60–120 min until polarized microscopy shows no undissolved particulate, followed by filtration through a 0.2 µm nylon membrane. The mixture is filled by one-drop-fill equipment inside an ISO 14644-1:2015 Class 5 cleanroom, after photoalignment polyimide exposure with polarized UV and cell gap formation with 3–5 µm silicon dioxide spacers; edge sealing uses UV-curable adhesive. Terminal products are passive-matrix electronic shelf labels and sunlight-readable instrumentation modules. The critical electrical parameter is voltage holding ratio; residual ionic impurities or dye dimer precipitation can lower VHR below 98% at 60°C and cause image sticking in matrix-addressed panels. Compliance documentation includes REACH EC 1907/2006 SVHC screening and IEC 62474:2018 Ed.1 material declaration. The dichroic order parameter S is characterized from anisotropic absorbance according to JIS Z 8722:2009 and should be at least 0.72; absorbance anisotropy A∥/A⊥ below 7 is generally rejected for positive-mode guest-host cells because contrast ratio collapses under off-axis viewing. Published data for exact VHR values in this specific dye-host configuration are limited, so downstream qualification includes a 250-hour VHR drift test at 60°C, 90% RH.
For foldable AMOLED circular polarizer stacks, dye-based polarizer layers are selected when the panel must survive dynamic folding at 1–3 mm bend radius without microcrack propagation. The polarizer special dye is incorporated at 0.6–1.0 wt% of PVA solid in the stretched film; in thin-film polarizer variants based on a lyotropic liquid crystal host, the dye-to-colloid mass ratio is 0.15–0.30. After dyeing, the PVA web is uniaxially stretched 4–5× in boric acid at 55–60°C, laminated to a quarter-wave retardation film and pressure-sensitive adhesive by roll-to-roll lamination at 25±2°C and 50±5% RH, then edge-trimmed by galvanometer laser cutting. Each roll is inspected for point defects larger than 50 µm; optical acceptance includes single-piece transmittance ≥ 42%, polarization efficiency ≥ 99.0%, and haze ≤ 1.0% under ASTM D1003-21 and ISO 13468-2:2016. Compliance verification includes RoHS 2011/65/EU Annex II, REACH EC 1907/2006 Article 33, and halogen thresholds per IEC 61249-2-21:2003. The terminal product is the circular polarizer laminate used in foldable OLED smartphone and notebook panels.
Near-eye display combiners use polarizer special dye in a polymerizable reactive mesogen ink rather than a PVA film. The addition level is 3.0–8.0 wt% of non-volatile solid in the ink, adjusted so that the cured coating achieves polarization efficiency ≥ 99.0% across 450–650 nm. The ink is filtered through a 0.1 µm PTFE membrane directly before slot-die coating; uncontrolled agglomeration above the membrane pore size causes streaking at coating speeds above 10 m/min. The slot-die gap is set at 50–100 µm with a wet film thickness of 8–15 µm on a cyclo-olefin polymer substrate. After a 60–90°C drying zone, the coating is UV-cured at 365 nm with a dose of 800–1,500 mJ/cm² under nitrogen containing less than 50 ppm O₂, then annealed at 80–120°C for 30–60 min to stabilise nematic order. Compliance for optical assembly references ISO 14644-1:2015 Class 5 and ASTM E595-15 for outgassing, while halogen screening follows IEC 62321-7-1:2015/AMD1:2023 and heavy-metal screening follows IEC 62321-5:2013. Terminal products are waveguide polarizer films and thin-film polarizing beam-splitter layers used in AR birdbath optics, micro-OLED polarizers, and VR LCD backlight rejection layers.
Outdoor panels using dye-stuff polarizers are processed on the same PVA tenter-frame platform as automotive film but with a higher dye bath concentration of 0.6–1.2 g/L to compensate for the lower intrinsic transmittance of dye-based absorption. The dyed PVA element is stretched 4–5× at 55–60°C in boric acid, then dried under tension at 70–80°C for 3–5 min before lamination with UV-blocking triacetyl cellulose. Terminal products include railway passenger information displays, marine chart plotters, and outdoor digital signage panels in which direct sun load can raise internal panel temperature above 90°C. Environmental qualification is documented against IEC 60068-2-78:2012 for damp heat steady state, ISO 4892-2:2013 for xenon-arc weathering, and IEC 61249-2-21:2003 halogen-free thresholds. The main limitation is the trade-off between polarization efficiency and single-piece luminance transmittance: as dye concentration increases, dichroic absorption rises but transmittance declines; suppliers therefore specify a transmittance window of 38–42% at 550 nm and a polarization efficiency floor of 99.0%. Production bottlenecks include edge curl at the boric acid stage when web tension variance exceeds ±0.2 N/m, and dye bath foaming when air entrainment exceeds 0.1 L/min in high-speed immersion tanks.
When diagnostic monochrome LCD modules operate under prolonged backlight irradiation, polarizer special dye is incorporated at 0.5–0.8 wt% relative to PVA dry mass in a dyeing bath maintained at 40±2°C, with residence time of 180–240 s. The dyed film is uniaxially stretched 4–5× in boric acid crosslinking solution at 55–60°C, then dried under tension before lamination with anti-reflective triacetyl cellulose. The dye absorbance profile is specified to keep panel chromaticity shift Δu'v' below 0.005 after 5,000 h of LED or CCFL backlight irradiation, evaluated under ISO 11664-2:2007. Compliance for finished diagnostic display systems references ISO 13485:2016 and IEC 60601-1:2005/AMD2:2020 when integrated into medical electrical equipment; component-level declarations include RoHS 2011/65/EU Annex II and REACH EC 1907/2006 SVHC screening. Terminal products are monochrome and color diagnostic LCD monitors used in radiology reading rooms and surgical endoscopic visualization. The principal process limitation is particulate contamination: dye aggregates above 5 µm in the final polarizer create point defects that fail 20× polarized-light inspection, so the aqueous dye solution is filtered through 0.45 µm polypropylene before the dyeing bath and bath turnover is controlled to prevent foam transfer.
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The material designated Polarizer Special Dye Electronic/EL Grade is supplied as a purified organic dichroic colorant for stretched poly(vinyl alcohol) (PVA) polarizing films used in electroluminescent display and edge-lit backlight stacks. The grade is characterized by a controlled absorbance maximum in the visible region, low extractable ionic residue, and defined solubility in the water-miscible solvent systems used for casting dope preparation. Model identification is manufacturer lot-specific rather than a universal ISO model designation; batch traceability is maintained through certificate-of-analysis numbers and retest dating. The product is not a single chemical species but a formulated colorant fraction whose exact molecular composition remains proprietary. User specifications therefore reference optical performance in a standard PVA draw film as well as impurity ceilings.
The material is intended for high-purity polarizing layers in electroluminescent display stacks, flat-panel display polarizers, and other iodine-free dichroic film constructions. It is differentiated from general-purpose polarizer colorants by its electron-grade purification sequence, which includes recrystallization, solvent stripping, and sub-0.45 μm filtration. The grade is supplied as a dark crystalline powder in sealed containers, and the appropriate incoming specification is not a single data-sheet value but a certificate-of-analysis profile that includes optical performance in reference PVA film and residual impurity limits.
In an electroluminescent stack, the polarizer film is adjacent to indium tin oxide or thin-film transistor layers. Ionic residues in conventional dye grades migrate under the influence of alternating drive fields. Chloride is the most critical contaminant because it accelerates indium tin oxide corrosion under damp heat. The Polarizer Special Dye Electronic/EL Grade is therefore controlled for chloride below <10 mg/kg; conventional optical dyes can contain 100–500 mg/kg chloride after synthesis. This difference is measurable as edge ingress after 1000 h at 85 °C/85 % RH per IEC 60068-2-78.
Sulfonated byproducts and low-molecular-weight ionic species also interfere with polarizer-adhesive compatibility. In production-scale accelerated aging, the failure mode is not immediate color shift but progressive delamination at the polarizer-adhesive interface. Automated optical inspection under crossed-polarizer imaging classifies edge ingress greater than 0.5 mm as reject. Because the EL grade is filtered and ion-reduced, edge ingress associated with mobile chloride is reduced in damp heat exposure.
The grade also excludes particulate matter that would otherwise produce point defects in roll-to-roll coating. Filtration through a 0.45 μm membrane is a standard release criterion. Dye lots that fail the 0.45 μm filtration test or exceed the <10 mg/kg chloride ceiling are not released for electronic-grade use.
The following incoming quality-control profile applies to the Polarizer Special Dye Electronic/EL Grade. The acceptance bands are representative of polarizer-grade dyes for display use; the certificate of analysis for each lot contains measured values and expiration dating.
| Parameter | Acceptance band | Analytical method |
|---|---|---|
| Moisture | <0.5 wt% | ASTM E203 / Karl Fischer titration |
| Residue on ignition | <0.1 wt% | ASTM D5630 |
| Iron | <5 mg/kg | ISO 11885 |
| Chloride | <10 mg/kg | Ion chromatography after aqueous extraction |
| Sulfate | <10 mg/kg | Ion chromatography after aqueous extraction |
| Absorbance maximum λmax in methanol | 550–650 nm | ASTM E169 UV-visible spectrophotometry |
| Dichroic ratio in stretched PVA | >20 | Polarizing spectrophotometer, 25 °C |
Chloride and sulfate are determined after aqueous extraction at 25 °C for 1 h; the extraction ratio is 1:10 (w/w). Iron is determined by closed-vessel microwave digestion followed by ICP-OES. Dichroic ratio is measured on a cast and stretched PVA film containing 0.5 wt% dye relative to dry polymer, drawn at a draw ratio of 5:1. Optical acceptance is not absolute; it is referenced to a standard PVA grade on the user’s coater because PVA molecular weight, boric acid level, and drying profile shift the final polarization efficiency.
For slot-die coating, the dye is dissolved in a water/2-propanol mixture, typically 1:1 (w/w), at 25–40 °C. The solution is then blended with PVA solution and filtered through a 0.2 μm PTFE membrane. High-shear dispersion is not normally required. If the dye powder has absorbed moisture during storage, pre-drying at 60 °C under −0.08 MPa for 4–8 h is necessary before weighing. Dissolving the powder in pure water at low temperature may reduce solubility below the process threshold and cause precipitation at the slot-die lip.
On a 250 mm wide pilot coater using a slot-die gap of 180 μm and line speed of 8 m/min, unfiltered dope containing insoluble fraction above 50 mg/kg produced transverse streaks within 15–20 min. Installation of 0.2 μm membrane filtration reduced the defect count from 12 defects/m² to 0.2 defects/m². The die lip and chill roll are maintained at 10–15 °C; lower chill-roll temperatures can cause a local viscosity increase and nonuniform wetting.
The dissolved dye is sensitive to multivalent metal ions. Contact with iron or copper surfaces can produce metachromatic complexes that shift the absorbance maximum by 5–15 nm. Process vessels and transfer lines are therefore specified in 316L stainless steel or fluoropolymer-lined equipment. The solution should be degassed under vacuum below 50 kPa before slot-die delivery to prevent microvoid defects.
The drawn PVA film is stretched uniaxially at a draw ratio of 4:1 to 6:1 after dye uptake. Optical performance is evaluated with a UV-visible polarizing spectrophotometer. Single-plate transmittance and polarization efficiency are calculated from parallel and cross transmittance. For this product category, single-plate transmittance is commonly specified at 42–46 % with polarization efficiency above 99 % at 550 nm. Published data for this specific configuration is limited; therefore, acceptance limits are established on the user’s coater using a reference PVA grade and a defined draw ratio.
If the draw ratio varies outside ±0.2 of the target, molecular alignment of the dye is insufficient and the dichroic ratio falls below the required >20 threshold. The resulting film shows lower polarization efficiency and weak oblique-angle performance. Draw ratio control is therefore more critical for this grade than for isotropic colorant addition in non-polarizing optical films.
Accelerated optical retention testing is conducted after damp heat exposure per IEC 60068-2-78. The film is conditioned at 85 °C/85 % RH for 1000 h and then remeasured. The grade is specified to retain 95 % of initial polarization efficiency after this exposure. By comparison, iodine-based polarizers can degrade more rapidly under the same conditions, particularly at the edges where moisture ingress is highest.
In comparison with iodine-based polarizers, the Polarizer Special Dye Electronic/EL Grade is selected when damp heat stability and direct-current field tolerance are constrained. Iodine-based films typically deliver higher single-plate transmittance, often 42–45 % at 550 nm, but are susceptible to degradation at 80 °C dry and 60 °C/90 % RH within 500 h. Dye-based films are specified to retain 95 % of initial polarization efficiency after 1000 h under the same damp heat conditions.
Against ordinary dye-based polarizer colorants, the EL grade differs in residual metal-ion control and particulate filtration. Ordinary grades may have iron levels up to 20 mg/kg and may be supplied as non-filtrated powder. The EL grade passes 0.45 μm filtration and is limited to <5 mg/kg iron. Against textile-grade colorants, the difference is more pronounced: textile dyes can contain sulfate above 1000 mg/kg and diluents that cause haze and ionic migration in optical stacks. Those products are not suitable for deposited indium tin oxide or thin-film transistor backplanes.
The material should not be combined with amine-based additives because amine protonation may shift the absorbance maximum by 5–15 nm and alter the dichroic ratio. Strong oxidizing agents are incompatible. Containers should be amber glass or fluoropolymer-lined, sealed under nitrogen, and stored at 2–8 °C. Once opened, the material should be used within 30 days or re-dried before use. The shelf life from date of manufacture is 12 months under the specified storage conditions.
