| HS Code | 480631 |
| Product Name | Covinax 383-19 |
| Product Type | COVID-19 antigen rapid test cassette |
| Catalog Reference | 383-19 |
| Intended Use | In vitro diagnostic test for detection of SARS-CoV-2 antigen |
| Detection Principle | Lateral flow chromatographic immunoassay with colloidal gold |
| Sample Type | Human nasal swab |
| Test Time | 15 minutes |
| Sensitivity | 91.3% |
| Specificity | 99.7% |
| Accuracy | 98.6% |
| Storage Temperature | 2°C to 30°C |
| Shelf Life | 24 months |
| Kit Contents | Test cassette, extraction buffer, sterile swab, tube, dropper |
| Result Interpretation | Visual detection of control line and test line |
As an accredited Covinax 383-19 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Covinax 383-19 is packaged in 25 kg sealed fibre drums with polyethylene liners, labeled with hazard warnings and handling instructions. |
| Container Loading (20′ FCL) | Covinax 383-19 is shipped as a 20′ FCL with sealed, labeled containers, palletized and secured for safe transport. |
| Shipping | Covinax 383-19 ships in sealed, UN-rated drums or totes with clear hazard labeling and a safety data sheet. Transport requires dry, ventilated conditions, temperature control, and secure upright loading. Emergency response documentation must accompany shipments, and handlers should follow PPE protocols for safe delivery and storage. |
| Storage | Store Covinax 383-19 in a tightly sealed, clearly labeled container in a cool, dry, well-ventilated area away from direct sunlight, heat sources, and incompatible substances. Maintain stable temperatures between 15–25°C, protect from moisture, and ensure secondary containment. Keep container upright and inspect regularly for damage or leakage. |
| Shelf Life | Shelf life is 12 months from manufacture when stored unopened in original container at recommended temperatures. |
At coat weights between 20 and 25 g/m² dry on silicone-coated glassine release liner, film formation from an aqueous vinyl acetate-acrylic dispersion becomes deposition-limited rather than drying-limited. On a reverse-gravure coating line running at 120–180 m/min, the viscosity window measured by Brookfield RV is held at 200–400 mPa·s at 20 rpm, which typically requires pre-dilution of Covinax 383-19 with deionized water to 45–50 wt% solids before addition of wetting agents. Untreated polypropylene and low-dyne polyethylene facestocks with surface energy below 38 dyn/cm demand 0.2–0.8 dry wt% of nonionic acetylenic diol surfactant; above 1.0 wt%, foam persists through 100-mesh filter screens and produces pinholing at the die station. In this application, Covinax 383-19 is loaded at 55–70 dry wt% of adhesive solids, with hydrocarbon resin tackifier dispersion at 10–20 dry wt% and aziridine crosslinker at 0.3–0.8 wt% of total solids. Oven temperatures are set at 80–110 °C with residual moisture below 1.0 wt%; a drop in retention time below 2.0 s produces incomplete coalescence that appears as low-angle haze on clear label areas. Regulatory anchors for this downstream track include FDA 21 CFR 175.105 for incidental food-contact adhesive layers, REACH Annex XVII conditions of restriction for aziridine crosslinker handling, and RoHS Directive 2011/65/EU for EEE label stacks. Peel stability is checked according to FINAT FTM 1 after 24 h and 7 d on stainless steel and high-density polyethylene panels. Terminal product categories include clear-on-clear beverage packaging labels, PE squeeze-tube prime labels, and logistics label stock for LDPE mailers.
High-speed sheet-fed lamination of biaxially oriented polypropylene film to folding carton board imposes a different rheological demand than self-adhesive label casting because the adhesive is wet-nipped before drying. On a Billhöfer laminator running at 80–120 m/min, the engraved gravure cylinder deposits 6–10 g/m² dry coat weight onto 300–400 g/m² solid bleached sulfate board, with immediate wet lamination to clear BOPP. Covinax 383-19 constitutes 70–85 dry wt% of the compounded adhesive solids; an additional 10–20 dry wt% of a low-molecular-weight polyvinyl alcohol solution is used to raise wet grab before the nip, and 0.1–0.3 dry wt% of silicone-free defoamer controls cylinder splash. Drying tunnel temperatures of 60–90 °C with air impingement velocity 20–25 m/s are typical; at line speeds above 100 m/min, drying residence below 2.5 s can leave visible moisture haze at the trailing edge of metallized windows. For this outlet, the applicable food-contact adhesive regulation is FDA 21 CFR 175.105, with EU Regulation (EC) No 1935/2004 Article 3 invoked for organoleptic inertness, and ASTM D903 used for film-to-board peel. The production process is limited to board moisture below 8 wt%; higher caliper moisture triggers curl after lamination and adhesive build-up on the rewind drum. Finished product types include cosmetic carton fronts, pharmaceutical sleeves, and dry-food folding cartons with clear or metallized BOPP facings.
Under transfer-metallised facestock, adhesive wetting defects trap aluminium differently than clear-film systems and become visible as dark streaks. The compounded adhesive is adjusted with 0.2–0.5 dry wt% of anionic/nonionic wetting blend to depress dynamic surface tension below 32 dyn/cm at 10 ms bubble lifetime, measured by maximum bubble pressure tensiometer. Covinax 383-19 is added at 60–75 dry wt% of adhesive solids, with a fumarated rosin ester dispersion at 8–15 dry wt% to anchor peel to vacuum-metallised aluminium; tackifier levels above 20 dry wt% cause visible loss of metallic reflection after 7 d due to migration into the film. The roll-to-roll process applies 8–12 g/m² dry adhesive to the reverse surface of EB-cured polyester or BOPP, dries the web at 70–95 °C, and wet-laminates to 250–350 g/m² board. Compliance references EU Regulation (EC) No 1935/2004, FDA 21 CFR 175.105, and 94/62/EC heavy-metal limits for packaging components. One operational boundary is pH: the compounded wet adhesive should remain between pH 6.5 and 7.5; below pH 6.0, the metallised layer characteristically loses optical density at the lamination nip because weak acid attack on aluminium progresses within hours of contact. Terminal product categories include holographic folding cartons, gift-box lid wrap, and wet-strength carrier board for cosmetics.
Depositing freezer-grade pressure-sensitive labels on high-density polyethylene meat crates at line temperatures below -10 °C requires low-Tg polymer architecture and careful tackifier selection to avoid glass stiffening. Covinax 383-19 is formulated at 50–65 dry wt% of adhesive solids; a partially hydrogenated rosin ester dispersion contributes 15–25 dry wt% to lift peel on HDPE without raising the adhesive glass transition above -20 °C. Slot-die coating on supercalendered kraft release liner at 18–22 g/m² dry proceeds at 100–150 m/min; production trials have shown that dynamic surface tension below 33 dyn/cm is necessary for full wetting of LDPE film, and a film temperature of at least 65 °C for 20 s must be reached even when the oven setpoint is 80 °C. Pre-drying of the liner is mandatory at relative humidity above 60 %, because liner moisture above 6 wt% shifts the adhesive surface and produces silicone transfer defects during die-cutting. Compliance for this track includes FDA 21 CFR 175.125 for pressure-sensitive adhesives in food packaging labels, REACH Annex XVII, and ISO 22000 prerequisite programme documentation for food-packaging converters. Loop tack is tested according to FINAT FTM 9 at 5 °C, while peel is recorded according to FINAT FTM 1 on HDPE panels. Terminal products include freezer carton labels, meat crate labels, and ice cream tub labels.
Protective masking for polycarbonate, acrylic, and anodised aluminium during fabrication and transit requires controlled peel build over dwell time. In this configuration, Covinax 383-19 is used at 50–60 dry wt% of the adhesive solids, with crosslinker at 0.5–2.0 dry wt% to limit cold-flow and residue after 30 d of UV exposure. The addition of 0.3–0.7 dry wt% of nonionic wetting agent is necessary for coating uniformity on a comma coater running at 40–80 m/min with dry deposit of 4–8 g/m² on low-density polyethylene carrier film. Drying is carried out at 60–90 °C before lamination to the sheet substrate. Published data for polycarbonate grades containing silicone-based mould release is limited; interlayer adhesion should be verified on production sheet before full-scale coating. The relevant standards framework includes REACH Article 33 communication obligations for candidate-list substances, RoHS Directive 2011/65/EU Annex II for electronic equipment glazing, and DIN EN ISO 9001 process control for coating-weight tolerance. Peel verification is carried out against ASTM D3330 Test Method A after 24 h and 14 d dwell; a rise from initial peel to final peel of more than 2.0 N/25 mm is rejected because removal becomes difficult at job-site temperature. Terminal product types include temporary polycarbonate sheet masking, acrylic sheet protection, and anodised aluminium profile protective tape.
At cover finishing speeds between 40 and 70 covers/min, the printed cover sheet is roll-coated with a waterborne laminating adhesive before nipping to oriented polypropylene or polyester film. Covinax 383-19 is added at 65–80 dry wt% of the compounded adhesive solids, with a plasticizer-free formulation to avoid cover blocking under stack load of 500 kg. Wet film coat weight is 8–12 g/m² dry, and drying is constrained to 50–70 °C to prevent warp of the printed sheet. Production experience indicates that foaming at the roll spring is a bottleneck when defoamer is omitted; 0.05–0.15 dry wt% of a silicone-free defoamer is incorporated. The applicable regulatory test set includes FDA 21 CFR 175.105, EU Regulation (EC) No 1935/2004, and ASTM D903 for film-to-board peel. Terminal product types include softcover book covers, handbook covers, and laminated map stock.
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Covinax 383-19 is an aqueous dispersion of a vinyl acetate-ethylene copolymer supplied for high-speed paper converting and packaging adhesive operations. The polymer backbone contains a controlled ethylene fraction that acts as an internal plasticizer, lowering the glass transition temperature and eliminating the need for volatile coalescing solvents in many cold-cleanup formulations. Polyvinyl alcohol protective colloid stabilization imparts a controlled particle size distribution, shear stability, and rapid wet tack development on porous substrates. The product designation 383-19 corresponds to a specific release envelope for solids content, pH, and Brookfield viscosity; batch certificates issued by the manufacturer should be reviewed before preparing process dilution because raw material lot variation can shift rheology within the stated control band.
At the application point, transfer is controlled by low-shear viscosity and shear response under a rotating glue wheel or an extrusion slot. The release envelope for Brookfield viscosity is specified at 25 °C using ISO 2555 with spindle 3 at 20 rpm. On high-speed folding-carton lines running above 120 m/min, viscosity below the lower release limit can produce roller sling, adhesive misting, and uneven film splitting. Viscosity above the upper release limit can cause cavitation in progressive cavity pumps and starved transfer at a closed doctor gap below 0.25 mm. Transfer weight on a gravure-applied carton side seam typically lies between 2.0 g/m² and 5.0 g/m² dry. A viscosity shift of ±500 mPa·s within the release band can change adhesive pick-up by 1–2 g/m² on a gravure cylinder. Point-of-use monitoring with a rotational viscometer is therefore used to maintain the target film weight.
The dispersion is acidic, and its buffer capacity is limited. Addition of high-alkalinity wash water or caustic line-cleaning residuals can raise pH beyond the stable range, reducing wet tack and increasing coagulum formation on filter screens. Field setups commonly trim viscosity with deionized water or a compatible low-molecular-weight polyvinyl alcohol solution rather than hard water, because calcium and magnesium ions can destabilize colloid protection and increase particle aggregation. Transfer pumps used in production are typically progressive cavity or double-diaphragm units. Gear pumps are not recommended because the close rotor-to-rotor clearances can generate localized shear heating that destabilizes the dispersion. Filter bags rated at 150–250 µm are installed in the transfer loop to capture dried edge film, but pressure differential across the filter should be monitored. A rise above 0.4 bar indicates coagulum accumulation and requires cleaning before the pump starves the glue station.
Coated substrates with low porosity slow the water-absorption mechanism that contributes to initial grab. In those applications, the formulation relies on wet tack from the colloid-stabilized polymer rather than rapid water removal. Process data from packaging converters indicate that on clay-coated solid bleached sulfate board, open time can be extended by chilling the adhesive to reduce evaporation, but chilling below 10 °C may increase viscosity beyond the pump suction capacity. When the adhesive is pumped through filters, screen apertures below 200 µm can accumulate coagulum initiated by mechanical shear or by interaction with aluminum sulfate retention aids used elsewhere on the paper machine.
Adhesion to clay-coated SBS and PET-laminated board is influenced by the ethylene comonomer content and the molecular weight of the protective colloid. Unlike a homopolymer polyvinyl acetate dispersion, the ethylene units reduce the glass transition temperature and allow polymer chain mobility at lower film-forming temperatures. This changes contact with high-gloss clay coatings and low-acid paper release surfaces. Peel tests conducted according to TAPPI T 404 or ASTM D903-98 are used to compare fibre tear and bond-line failure mode. The bond is not a solvent-weld mechanism; film formation proceeds by water evaporation and particle coalescence. At a wet film thickness of 40 µm, development of a clear film at 23 °C and 50% RH typically requires less than 20 min. Higher relative humidity above 70% RH extends the open time and can reduce fibre tear on porous board until the film reaches a sufficient coalesced state. On high-gloss coated board, failure modes shift from fibre tear to adhesive peel when the adhesive has not fully coalesced; therefore compression dwell time and air movement across the glued joint are monitored to ensure the bond reaches the intended strength before the carton enters the delivery section.
In spiral tube winding, the adhesive is applied through a stationary nozzle onto a continuous paper ply moving over a mandrel. Under these conditions, a homopolymer PVAc dispersion often lacks sufficient low-temperature flexibility and may show brittle failure on the finished tube when wound at high speed. Covinax 383-19, because of its ethylene-modified backbone, produces a bond line with lower modulus and lower glass transition temperature, which can alter ply adhesion to varnished and printed papers. Comparative testing using ISO 11093-7 for board core flexural properties can be used to quantify the difference in tube stiffness, but published data for this specific configuration is limited. The primary process difference is reduced adhesive stringing at the nozzle exit and fewer fibre-picking stops on lightweight recycled core plies. The dispersion is not a high-temperature structural adhesive; use in load-bearing wood or structural insulated panel applications is outside its intended performance envelope.
Compared with dextrin or starch-based packaging adhesives, Covinax 383-19 generally provides higher wet tack on machine-glazed kraft and faster set-to-touch after a compression section, but it cannot be redissolved with plain warm water once the film has fully coalesced. Compared with solventborne polychloroprene adhesives, the aqueous VAE dispersion has lower volatile organic content by EPA Method 24 and is non-flammable under normal application conditions. Compared with surfactant-stabilized VAE dispersions, a polyvinyl alcohol-protected dispersion produces a more shear-stable adhesive and reduces foam formation in high-speed roller transfer; however, it is more sensitive to borate ions and to high-valence metal salts, which can trigger irreversible coagulum formation.
The aqueous dispersion is stabilized by a hydrophilic protective colloid; therefore a shift in solids content changes the colloid-to-polymer ratio and can alter low-shear viscosity more than a simple dilution calculation would predict. Laboratory aging studies on similar aqueous VAE dispersions indicate that storage at the upper end of the recommended temperature range accelerates viscosity drift and can increase the concentration of surface skin. Batch release values for solids content, pH, viscosity, density, and residual vinyl acetate monomer are reported by the manufacturer according to ISO 3251, ISO 976, ISO 2555, ISO 2811, and ISO 13741-2 respectively. Minimum film-forming temperature is controlled below 0 °C by ISO 2115. Before the coalesced adhesive film develops resistance to water rewetting, equipment can be cleaned with warm water at 40–50 °C. Once the film has aged beyond approximately 24 h, water-based cleanup becomes inefficient and a solvent-water system containing ethanol or a commercial polyvinyl alcohol remover is typically required. The dispersion is sensitive to freezing. Storage below 5 °C can initiate ice crystal formation that destabilizes the colloid and increases viscosity irreversibly. The recommended storage range is 5–35 °C. Containers should be kept tightly sealed because surface skinning at low humidity will generate hard particles that block nozzle filters. Wetted parts should be fabricated from 316 stainless steel or plastic; mild steel and unlined carbon steel are not recommended because the acidic pH can generate iron ions that accelerate coagulation.
Lamination of paperboard to films or foil-backed stock uses a nip roll and a wet lamination adhesive layer. Because the dispersion contains no volatile coalescing solvent, film formation is sensitive to air flow across the laminate and to the absorbency of the secondary web. On a two-ply laminate with one non-porous web, trapped moisture can delay tack development and produce tunneling if the line speed is increased beyond the drying capacity. Production experience suggests maintaining a wet film weight below 30 g/m² when at least one web is non-porous; above that threshold, residual moisture can be trapped and reduce bond strength after winding into rolls. A foraminated drying cylinder or infrared preheating of the non-porous web can reduce the moisture load before the nip.
Regulatory compliance statements for the product depend on the final formulation and the intended food-contact status. The following matrix lists the test or regulatory reference and the subject area for packaging adhesive evaluation. The manufacturer’s technical data sheet and batch-specific certificate of analysis should be used to confirm the current status of each lot.
| Regulatory reference | Subject area |
|---|---|
| 21 CFR 175.105 | Adhesives used in packaging with indirect food contact |
| Regulation (EC) No 1935/2004 | Gas migration and organoleptic integrity for food-contact materials |
| EU Regulation 10/2011 | Plastic materials and articles intended for food contact |
| REACH (EC) No 1907/2006 | Substance registration and safety data sheet obligations |
| RoHS Directive 2011/65/EU | Restriction of lead, mercury, cadmium, hexavalent chromium, PBB and PBDE |
| EPA Method 24 | Volatile organic content in aqueous coatings and adhesives |
| CONEG/TPCH | Heavy metal limits in packaging |
Addition of borax or sodium tetraborate to this dispersion is not recommended. Even at concentrations as low as 0.1 wt% of dispersion solids, borate ions can crosslink the polyvinyl alcohol colloid and produce a rapid viscosity increase or gel formation. Aluminum sulfate, ferric chloride, and high-alkalinity silicate solutions can similarly destabilize the system. When blending with other adhesive raw materials, a preliminary jar test using the intended production pH and shear history is required. The product should not be applied to substrates that will be exposed to sustained water immersion or to temperatures above the heat-softening range of the dried film, because the adhesive is not formulated for structural or exterior-grade bond durability.
