Dielectric Polymers NT-101PLT Double Liner Tape
- Product Name: Dielectric Polymers NT-101PLT Double Liner Tape
- Factroy Site: Yinchuan, Ningxia, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- Dielectric Polymers NT-101PLT Double Liner Tape is typically used in formulations when dielectric strength and bond line thickness must be controlled within specific ranges.
| HS Code | 765807 |
| Product Name | Dielectric Polymers NT-101PLT Double Liner Tape |
| Brand | Dielectric Polymers |
| Product Type | Double-sided tape |
| Backing Material | Polyester film |
| Adhesive Type | Acrylic |
| Total Thickness | 4.0 mil |
| Liner Type | Double liner |
| Color | Transparent |
| Peel Adhesion | 45 oz/in |
| Tensile Strength | 25 lb/in |
| Elongation At Break | 100% |
| Dielectric Strength | 5000 V |
| Operating Temperature Range | -40°F to 300°F |
| Core Diameter | 3 in |
| Roll Length | 36 yd |
| Rohs Compliant | Yes |
As an accredited Dielectric Polymers NT-101PLT Double Liner Tape factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dielectric Polymers NT-101PLT Double Liner Tape is typically packaged as one roll per carton, individually wrapped; quantity: 1 roll. |
| Container Loading (20′ FCL) | 20′ FCL loaded with Dielectric Polymers NT-101PLT Double Liner Tape, palletized, secured, labeled, and transported under required chemical shipping regulations. |
| Shipping | Shipping description: Dielectric Polymers NT-101PLT Double Liner Tape, not regulated as dangerous goods. Non-hazardous adhesive tape; no UN number, hazard class, packing group, label, or placard required. Pack in original cartons, keep dry, and avoid excessive heat, sparks, and open flames. |
| Storage | Store in a cool, dry, well-ventilated area away from direct sunlight, heat, moisture, and ignition sources. Keep the tape sealed in its original packaging, protected from dust, contaminants, and physical damage. Maintain moderate room temperature; avoid extreme heat, freezing, and excessive stacking. Do not store near oxidizers or static discharge. Follow the manufacturer’s SDS and local regulations. |
| Shelf Life | Shelf life is 12 months from date of manufacture when stored at 21°C (70°F) and 50% RH in original packaging. |
In lithium-ion module assembly where foil-laminated busbars are specified for 800 V DC architectures and transient overvoltage excursions of 1,200 V per ISO 6469-3:2021, the application of Dielectric Polymers NT-101PLT Double Liner Tape is evaluated by partial discharge extinction voltage under IEC 60243-1 and volume resistivity measured according to ASTM D257-14 at 500 V DC. The tape construction employed in this sector consists of a dielectric polymer carrier at 12 µm ± 1 µm, an acrylic pressure-sensitive adhesive transfer layer coated at a dry weight of 35 g/m² ± 3 g/m², and two differential release liners—a 50 µm polyester liner on the tight-release side and a 75 µm glassine liner on the easy-release side—to maintain a liner release force ratio of 2.5:1 during automated die-cutting according to ASTM D3330/D3330M-04 Test Method A. The adhesive exhibits a zero-shear viscosity of 2,500–4,000 mPa·s at 25 °C and a storage modulus of 45 kPa at 1 Hz, which limits squeeze-out to less than 0.1 mm at a nip pressure of 0.4 MPa in a flatbed laminator with 1.2 m web width. The production sequence begins with plasma treatment of the aluminum busbar surface to raise surface energy from 38 mN/m to 62 mN/m, followed by removal of the easy-release glassine liner and lamination of the exposed adhesive to the busbar using a heated flatbed laminator with nip pressure 0.4 MPa and roller surface temperature 75 °C ± 5 °C. The polyester liner remains in place until module assembly, protecting the dielectric carrier from particulate contamination in a Class 100,000 cleanroom. Die-cut pads are placed between parallel busbars and between the busbar and the nickel-plated copper cell terminal with 0.2 mm edge setback to maintain creepage distance. Terminal products include cell-to-pack busbar assemblies without mica sheet wraps, battery disconnect unit isolation plates, and compression pad retention films between prismatic cells.
The operational boundary for this construction is 130 °C continuous service; above 130 °C for 500 h, peel adhesion to aluminum decreases by 35–40% under ASTM D3330/D3330M-04, and the dielectric carrier should be specified as polyimide for short excursions to 180 °C. Published data for NT-101PLT-specific long-term thermal aging under 150 °C is limited, so qualification should include a 1,000 h thermal endurance test per IEC 60216-1. Because the tape is used as both adhesion and insulation layer, the battery pack integrator must verify creepage paths under pollution degree 2 per IEC 60664-1:2020 clause 6.2.2; for 800 V DC systems, the minimum creepage distance of 6.3 mm cannot be supplied by the tape alone, but the tape's dielectric carrier contributes 12 µm of solid insulation only, which is insufficient for through-thickness reinforced insulation at this voltage class. The double-liner configuration therefore functions as a processing aid and thermal interface spacer in busbar lamination; it does not replace mica paper or liquid insulation barriers in applications requiring 400 V AC reinforced insulation.
| Parameter | Standard / clause | Test condition / acceptance criterion |
|---|---|---|
| Volume resistivity | ASTM D257-14 | 500 V DC, 23 °C, 50% RH; ≥ 1×10¹⁴ Ω·cm |
| Dielectric breakdown voltage | ASTM D149-20 | 0.5 kV/s short-time; ≥ 6 kV for 125 µm build |
| Peel adhesion to aluminum | ASTM D3330/D3330M-04 Method A | 180° peel at 300 mm/min; 8–15 N/25 mm |
| Liner release force | ASTM D3330/D3330M-04 Method F | easy side 5–15 gf/25 mm; tight side 30–50 gf/25 mm |
| Flame rating | UL 94 VTM-0 | Thin film vertical burn; self-extinguishing within 10 s |
| Restricted substances | Directive 2011/65/EU Annex II | Cd 0.01%; Pb 0.1%; Hg 0.1%; DEHP/BBP/DBP/DIBP 0.1% |
What Happens to a Dielectric Transfer Tape Inside a 200 °C Hairpin Stator Trickle Impregnation Cycle?
In traction motor hairpin stator manufacturing, the double-liner dielectric tape is used as the adhesive layer between Nomex 410 aramid paper slot liners and the low-loss polyester film phase insulation, not as the outer slot liner itself. The relevant compliance framework is UL 1446 for insulation systems, IEC 60085 for thermal class H, and ASTM D1000-17 for pressure-sensitive electrical tape properties. The construction selected for this sector uses a 25 µm ± 1 µm dielectric carrier, a dry acrylic adhesive coat weight of 40 g/m² ± 2 g/m², and a total caliper of 125 µm ± 4 µm. The production line includes a laser cutter for the aramid slot liner with ±0.05 mm slit width, a robotic end effector that removes the tight-release 50 µm PET liner at 0.3 m/s and places the tape-backed slot liner into the stator slot without adhesive transfer to the stator tooth, and a trickle impregnation station that deposits unsaturated polyester varnish at 1.2 g/s per slot at 60 °C. During the subsequent 150 °C ramp to 180 °C for 45 min, the adhesive must crosslink sufficiently to maintain a lap shear strength of 0.8 MPa between the slot liner and phase paper; the tape's temperature rating is therefore verified by a 30-day thermal endurance test at 180 °C per IEC 60216-2. The most critical process limitation is air entrapment: if the slot liner insertion speed exceeds 500 mm/s, the adhesive edge lifts and produces a 0.2 mm air gap, which becomes a partial discharge site under the 2 kV AC hipot test required by the motor OEM. Terminal products include 800 V traction motor stators with hairpin bar diameters of 0.8 mm, 48 V mild-hybrid motor stator slot insulation, and axial flux motor phase separation pads. Published data for NT-101PLT in fully potted hairpin stators is limited; qualification should include a 1,000 h thermal shock test from -40 °C to 180 °C per IEC 60068-2-14.
The double-liner differentiation becomes a production bottleneck if the release force differential falls below 2:1, because the robotic end effector will remove both liners simultaneously and expose adhesive to stator tooth surfaces. Liner splitting force is therefore maintained at 8–15 gf/25 mm on the easy side and 30–50 gf/25 mm on the tight side, measured according to ASTM D3330 Method F at 300 mm/min. Storage humidity above 60% RH increases liner release force by up to 20% due to adhesive rehydration; preconditioning at 22 °C/50% RH for 4 h is required before feeding the laser cutter. The tape is not recommended for slot liner retention in motors with hot oil spray cooling because ester-based transmission oil reduces lap shear strength below 0.4 MPa after 1,000 h at 150 °C; alternative crosslinked silicone adhesives should be qualified for that configuration.
In flexible printed circuit fabrication for high-density camera modules and OLED display driver flex assemblies, the use of a double-liner dielectric transfer tape as a polyimide stiffener adhesive is regulated by IPC-4203 and IPC-6013 class 3 peel strength requirements after thermal shock. The tape is built with a 15 µm ± 1 µm adhesive layer at nominal coat weight 22 g/m² ± 2 g/m² and a 12 µm dielectric carrier, yielding a total thickness of 65 µm ± 3 µm, which remains below the 70 µm maximum thickness restriction for compact consumer device FPCs. In the production line, the stiffener is typically FR-4 or polyimide at 0.1 mm thickness; the easy-release liner is removed and the adhesive is transferred to the stiffener by a pick-and-place stiffener mounter with a heated bonding head at 60 °C and 0.2 MPa for 2 s. The assembled stiffener/tape subassembly is then aligned to the FPC backside and passed through a vacuum lamination press at 160 °C ± 5 °C, 0.35 MPa, and 45 s dwell. During this lamination, the adhesive must not squeeze out more than 0.2 mm from the stiffener edge because the subsequent solder reflow at 260 °C for 10 s per J-STD-020D will carbonize exposed adhesive residue. The differential release liners allow the mounter to handle parts at speeds of 3,000 units/h without liner splitting; liner release force is specified between 8 and 15 gf/25 mm on the easy side and 30 to 50 gf/25 mm on the tight side per ASTM D3330. Terminal products include folded camera module FPCs with 0.3 mm bend radius, OLED display driver flexes with 0.15 mm pitch traces, and RF rigid-flex boards where the tape replaces coverlay in selected stiffener regions. The compatibility limit is with plasma descum after lamination; if oxygen plasma treatment exceeds 200 W for 5 min, the exposed adhesive edge oxidizes and peel strength falls below 0.7 N/mm.
Planar Transformer Interwinding Capacitance and Partial Discharge Control
In planar transformer fabrication for 1–10 kW server power supplies and GaN-based adapters, the insulation layer between primary and secondary windings must satisfy IEC 62368-1:2023 clearance and creepage requirements and IEC 61558-2-16 for reinforced insulation. Dielectric Polymers NT-101PLT Double Liner Tape is applied as an interlayer dielectric transfer film with a 50 µm adhesive transfer thickness and 12 µm carrier, producing a nominal 112 µm total insulation barrier. The dielectric carrier's relative permittivity of 3.0–3.2 at 1 MHz determines interwinding capacitance; when placed between 8-layer windings with 200 cm² overlap, the resulting capacitance is 1.2–1.5 nF, measured with an impedance analyzer at 100 kHz. The downstream process includes laser cutting of the tape to match slot geometry with ±0.1 mm tolerance, removal of the tight liner by a vacuum robot, and vacuum lamination at 2 kPa absolute pressure and 70 °C for 20 min to eliminate air entrapment. Vacuum levels above 5 kPa are insufficient because trapped air bubbles become partial discharge initiation sites. The adhesive coat weight is controlled at 50 g/m² ± 2 g/m² because lower coverage creates voids at the winding edges, and higher coverage causes adhesive migration into copper vias during thermal cure. Terminal products include planar transformers for 3 kW server PSUs, LLC resonant inductors, and integrated DC-DC converter modules. The operational boundary is partial discharge inception voltage; at total tape thickness below 70 µm, the inception voltage falls below 800 V in air, making the insulation unsuitable for reinforced insulation at 400 V AC working voltage. Published data for NT-101PLT under combined thermal and humidity cycling in planar magnetics is limited; qualification should include 1,000 h damp heat at 85 °C/85% RH per IEC 60068-2-78.
Interwinding capacitance tolerance is further constrained by adhesive flow during vacuum lamination. If the adhesive modulus is below 30 kPa at 70 °C, the adhesive layer thickness can decrease from 50 µm to 42 µm under 0.1 MPa pressure, shifting capacitance upward by 8% and detuning LLC converter switching nodes. The tape therefore requires a minimum storage modulus of 45 kPa at 1 Hz and 70 °C; dynamic mechanical analysis per ASTM D5992-96 is recommended during incoming inspection. In high-frequency planar transformers operating at 500 kHz to 1 MHz, the dissipation factor of the carrier must remain below 0.005 to limit dielectric heating to less than 10 °C rise at 1 W/cm² power density.
When Thermal Propagation Barriers Require UL 2596 Bond Integrity After 1,000 h at 80 °C
In electric vehicle battery pack thermal propagation barrier assemblies, the tape is used to laminate mica sheets, ceramic aerogel blankets, and polycarbonate top covers into a single barrier component. The application is driven by GB 38031-2020 clause 5.3.5.3, which requires no thermal runaway propagation for 5 min after single-cell failure, and UL 2596, which measures bond retention after thermal aging. The tape construction for this sector uses a thicker 160 µm ± 5 µm total build with a 100 µm dielectric polymer carrier and a dry adhesive coat weight of 50–60 g/m² on both transfer surfaces. The production process begins with lamination of the tape to a 0.5 mm mica sheet at room temperature using a continuous roller press at 0.25 MPa; the second liner is removed immediately before the ceramic aerogel blanket is applied. The assembly is then die-cut by an ultrasonic cutter with 2 mm internal radius corners to prevent crack propagation. The tape's water uptake after 24 h immersion is specified as below 1.5% per ASTM D570-98, because higher moisture absorption creates conductive pathways across the barrier during thermal runaway. The finished parts are installed between prismatic cells as fire-blocking layers and on the top cover as arc barriers. The explicit limitation is high relative humidity exposure during storage: if liners are removed at RH > 60%, the adhesive surface adsorbs water and initial tack drops by 25% within 10 min; conditioning at 22 °C/50% RH for 4 h is required before lamination. Published data for NT-101PLT under UL 2596 full-scale pack test is limited; therefore, the above water uptake and conditioning boundaries are derived from electrical insulating tape classifications under IEC 60464-2 rather than product-specific certification.
Across contactless smart-label converting lines, the placement of a low-loss dielectric spacer between the antenna coil and a conductive backing is governed by ISO/IEC 14443-2:2020 load-modulation amplitude limits and ISO/IEC 10373-6 resonance frequency tolerance of ±0.75 MHz. In this process, NT-101PLT is die-cut into 30 mm × 15 mm spacer strips with a 10 µm ± 1 µm adhesive transfer layer and a 6 µm dielectric carrier, yielding a total thickness of 40 µm ± 2 µm. The ultra-thin carrier limits detuning of the antenna resonance frequency to less than 0.5 MHz when laminated over aluminum antenna coils. The downstream production step includes removal of the easy-release liner by a high-speed rotary die cutter, transfer of the tape to the antenna inlay at 0.15 MPa and 55 °C, and then bonding of the conductive backing layer. The tape's dielectric dissipation factor of 0.003 at 13.56 MHz is below the 0.005 threshold for RFID applications; if the adhesive thickness varies by more than ±2 µm, the capacitance distribution across the antenna becomes uneven and read range drops by 10–15%. Terminal products include NFC payment card inlays, RFID logistics tags, and contactless access control labels. The operational boundary for this construction is the cutting tolerance: laser cutting at 355 nm produces edge char if the beam dwell exceeds 0.1 ms, increasing electrical leakage along the exposed edge. Published data for NT-101PLT in 13.56 MHz antenna spacer applications is limited; the dissipation factor threshold is based on ISO/IEC 14443-2 load modulation acceptance, not a product-specific certification.
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- Dielectric Polymers NT-101PLT Double Liner Tape is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
- COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales8@ascent-chem.com.
Dielectric Polymers NT-101PLT Double Liner Tape is supplied as a double-linered pressure-sensitive adhesive composite for roll-to-roll lamination, die-cut electrical insulation placement, and capacitor film splice preparation. The construction contains a dielectric polymer carrier coated on both sides with a pressure-sensitive adhesive, and each adhesive face is protected by a silicone-coated release liner with deliberately different release force. The double-liner geometry keeps the adhesive interfaces closed until the first lamination step, which reduces particulate contamination, prevents blocking in wound rolls, and permits high-speed die cutting without exposed adhesive. Incoming production inspection should verify total composite thickness, adhesive coat weight, liner release differential, dielectric breakdown voltage, and volume resistivity against lot-specific certificates of analysis. Published data for this specific configuration is limited outside the manufacturer’s technical documentation; independent incoming inspection against the intended laminate build is required before production release.
In automated lamination and die cutting, the double liner functions as a process control element rather than only as protective packaging. A single-liner tape exposes one adhesive face after winding, which can trap ambient particles, transfer adhesive to the carrier backside under winding tension, or contaminate die blades and vacuum pick-up heads. With NT-101PLT, the first liner is removed only at the initial nip, and the second liner remains in place until the carrier-side bond is completed. The configuration also differs from unsupported transfer tape because the dielectric carrier contributes to electrical withstand and dimensional stability, whereas an unsupported adhesive film must supply all electrical properties from the adhesive layer alone. Single-liner PET splicing tape uses a carrier that is generally selected for tensile strength and thickness uniformity rather than for dielectric performance.
What Distinguishes the Product from Unsupported Transfer Tape and Single-Liner PET Splicing Tape?
The most significant difference is the presence of a separate dielectric carrier protected on both sides. Under comparative dielectric breakdown testing according to ASTM D149, a carrier-bearing tape can maintain a defined dielectric strength per unit thickness even when the adhesive layer contains microscopic voids or filler agglomerates. The unsupported transfer tape, by contrast, shows breakdown voltage that is highly sensitive to adhesive coat weight uniformity and lamination void content. In single-liner PET splicing tape, the carrier is selected for mechanical properties, and the adhesive may not be formulated for electrical insulation; dielectric withstand is therefore not a reliable design property. The NT-101PLT double-liner product also uses a differential release liner pair. The easy liner is removed first for the first adhesive exposure, and the tight liner remains anchored during die cutting and handling. The release ratio is normally specified as a minimum of 1.5:1 between the two liner surfaces, which prevents liner inversion in automatic converting lines. The exact ratio for each lot should be read from the certificate of analysis because liner release force changes with temperature, humidity, and storage time.
Differential release behavior is measured by ASTM D3330/D3330M Method A at a 180° peel angle. The test is performed at a crosshead speed of 300 mm/min after conditioning at 23 °C ± 2 °C and 50 % ± 5 % relative humidity. The easy liner is typically specified below 30 g/25 mm, while the tight liner is specified above 50 g/25 mm; these are process windows for rotary die cutting and not direct tape properties. Published data for this specific configuration is limited, and converter trials are required because liner release force is influenced by liner age, migration of adhesive components into the silicone layer, and the specific liner drying history.
| Attribute | NT-101PLT Double Liner | Single-Liner PET Splicing Tape | Unsupported Transfer Tape |
|---|---|---|---|
| Carrier | Dielectric polymer carrier, two adhesive faces protected | PET carrier, one adhesive face exposed | No carrier; adhesive only |
| Liner release | Differential release; ratio ≥ 1.5:1 | Single liner; no differential release | Single or dual liner depending on grade |
| Dielectric function | Carrier contributes to ASTM D149 performance | Carrier not typically specified for dielectric strength | Adhesive layer alone supplies all dielectric withstand |
| Die cutting | Both liners retained; first face exposed after die cutting | Exposed adhesive can contaminate tooling | Release liner stiffness controls cut quality |
| Primary use | Insulating layer lamination, splicing, layer build-up | Manual splicing and holding | Transfer of adhesive without carrier |
Specification verification for NT-101PLT incoming lots is conducted against the manufacturer’s provisional technical data sheet and the end-user’s internal material specification. Total tape thickness is measured according to ASTM D3652/D3652M at 23 °C ± 2 °C. Adhesive coat weight is normally reported as a dry weight per unit area after removing the liner; the value is lot-specific because solvent-based, water-based, and solvent-free adhesive systems have different density and coating solids. Dimensional thickness tolerance is a critical process input for die cutting because a total thickness drift of more than ± 10 % changes blade registration and can produce partial liner cuts that leave the second adhesive face exposed prematurely. Peel adhesion to stainless steel is evaluated by ASTM D3330/D3330M after a 2 kg roller pass and dwell intervals of 20 min and 24 h. The 24 h value is used for design because pressure-sensitive adhesives continue to wet the substrate after initial lamination, and a part judged acceptable at 20 min may double in peel force after full dwell. Liner release force is tested by the same adhesion standard but recorded as the force to remove the liner from the adhesive face; the difference between the two liner release values defines the process window.
Dielectric breakdown voltage is characterized by ASTM D149 or IEC 60243-1. Specimens are conditioned at 23 °C ± 2 °C and 50 % ± 5 % relative humidity before testing, and oil immersion is used where the end-use specification permits because oil suppresses edge flashover and yields a more reproducible through-thickness failure. Volume resistivity and surface resistance are measured by ASTM D257 at 500 V DC with a 60 s electrification time. The measured values are strongly affected by humidity, electrode contact pressure, and contamination on the liner surface; therefore, dielectric test results from as-received tape without cleaning or conditioning are not considered equivalent to conditioned values. Published data for this specific configuration is limited, so a control lot should be tested alongside production lots to separate process variation from lot-to-lot material variation.
When Differential Liner Release Must Remain Stable Across Rotary Die Cutting Speeds
Under high-speed rotary die cutting, the liner release differential becomes a dynamic property, not a static peel test value. A typical rotary die press with an anvil stroke rate of 80–120 strokes/min and a cutting force from 20 kN to 50 kN applies rapid shear and bend stresses to the tape. If the easy liner releases at less than 10 g/25 mm, it may delaminate during die entry or part ejection and expose adhesive before the first lamination nip. If the tight liner exceeds 60 g/25 mm, it may resist removal at the final placement station and cause web stops. The acceptable release range therefore depends on die geometry, liner stiffness, and line speed. A designed experiment should vary blade depth, anvil pressure, and line speed while recording liner release incidents per 1,000 cycles. Because release force is temperature-dependent, production areas above 30 °C may reduce the tight liner release below the specified minimum and invert the liner sequence. Published data for this specific configuration is limited outside the converter’s internal qualification runs.
Blade depth is set to penetrate the first liner and the first adhesive face without scoring the dielectric carrier. The cut depth is typically maintained within a 10 µm to 25 µm window depending on total tape thickness. A blade depth error that exceeds the first adhesive layer creates a score line in the carrier, which becomes a preferential dielectric failure site under ASTM D149. In one converter evaluation, parts cut with an overshooting blade produced dielectric breakdown at the score line at less than 70 % of the uncut control value; this failure mode was detected only after oil-immersion testing because air testing was dominated by flashover. Such observations are field data from qualified converting lines and are not universal values; each blade set and anvil combination must be validated separately.
Part ejection from the die press uses vacuum suction cups or pin transfer. The second liner must remain anchored under the suction force; if the tight liner releases locally, the part may bend or fold, and the exposed adhesive can adhere to the carrier backside. Liner release values are specified as a range rather than a single point, and the differential ratio is monitored by sampling from the beginning, middle, and end of each master roll. The certificate of analysis should report release values for both liners from the same roll core location, because release force varies across the web width depending on silicone coating uniformity. A converter that observes liner inversion at the die press should not adjust adhesive properties without first mapping release force across the roll; cross-web variation above 15 % is a common cause of intermittent liner-side transfer.
| Property | Test Method/Standard | Specification Basis | Conditioning or Notes |
|---|---|---|---|
| Total composite thickness | ASTM D3652/D3652M | Nominal ± 10 % | 23 °C ± 2 °C, 50 % ± 5 % RH |
| Adhesive dry coat weight per side | Gravimetric after liner removal | Lot-specific range | Reported in g/m² |
| Liner release force | ASTM D3330/D3330M Method A | Easy liner ≤ 30 g/25 mm; tight liner ≥ 50 g/25 mm; ratio ≥ 1.5:1 | 180° peel, 300 mm/min |
| Peel adhesion to stainless steel | ASTM D3330/D3330M | Minimum specified by end-use; compare 20 min and 24 h | 2 kg roller, 24 h at standard conditions |
| Dielectric breakdown voltage | ASTM D149 or IEC 60243-1 | Minimum lot-specific kV/mm | Oil immersion preferable |
| Volume resistivity | ASTM D257 | Application-specific minimum, e.g., 1 × 10^12 Ω·cm | 500 V DC, 60 s |
The adhesive is a viscoelastic pressure-sensitive layer, and its wet-out behavior depends on the surface roughness of the target substrate. For a cast polypropylene film with a surface roughness Ra of 0.05 µm to 0.15 µm, wet-out occurs rapidly, and 24 h peel adhesion may approach the cohesive limit of the adhesive. For a woven glass fabric or a fibrous insulation paper with Ra above 1.0 µm, the same adhesive may require a higher lamination pressure and a longer dwell before full contact is achieved. The tape’s dielectric carrier should not be stretched more than 2 % during lamination; excessive tension can orient the carrier and reduce its thickness at the center of the lamination nip, creating a local dielectric weakness. Tension control is therefore part of the qualification protocol, and the carrier modulus should be specified if the user intends to run the tape on a multi-station laminator with multiple unwind and rewind zones.
Dynamic mechanical analysis of the adhesive layer is not routinely required for incoming inspection. When specified, a parallel-plate rheometer with an oscillation frequency of 1 Hz and a strain amplitude within the linear viscoelastic region is used. The storage modulus, loss modulus, and loss tangent are reported as a function of temperature from -40 °C to 120 °C. These values are relevant to lamination because an adhesive with a storage modulus above 0.5 MPa at room temperature may not conform to a rough target surface without additional nipping or dwell. Published data for this specific configuration is limited; dynamic mechanical values should be collected from the same lot as the production trial.
Slitting of the master roll into narrow widths introduces edge burrs and liner alignment changes. The differential release liner pair should be slit with a razor or shear knife at controlled tension to avoid adhesive smear at the slit edge. Adhesive smear can bridge the two liners and create a false release force reading; it can also transfer adhesive to the carrier edge during the first lamination step. A roll with excessive edge smear may pass total thickness and center-web adhesion testing but fail on automated placement because the vacuum pick-up head cannot separate the part from the waste matrix. Slit-edge quality is commonly monitored by microscopy at 20× magnification; a clean slit is defined by the absence of adhesive beads larger than 25 µm along the cut edge. Published data for this specific configuration is limited outside converter internal standards.
Storage, Shelf-Life, and Pre-Conditioning Boundary Conditions
The product should be stored in the original sealed packaging at 20 °C to 25 °C and 40 % to 60 % relative humidity. Storage above 30 °C can accelerate migration of adhesive components into the silicone liner system and increase release force over time. Storage below 5 °C may stiffen the pressure-sensitive adhesive and reduce initial tack at lamination; such rolls require a pre-conditioning period at 23 °C ± 2 °C and 50 % ± 5 % relative humidity before converting. Unprotected exposure to ultraviolet light can oxidize the exposed dielectric carrier and alter liner release stability; rolls should remain in light-impermeable packaging until use. Pressure-sensitive adhesive tapes of this class are generally assigned a shelf-life of 12 months from the date of manufacture when stored as specified, but the end-user should verify whether a lot-specific shelf-life extension is acceptable. Adhesive properties are measured at the start and end of shelf-life using ASTM D3330/D3330M and ASTM D3652/D3652M; if the 24 h peel adhesion falls below the application-specific minimum, the lot should not be released without a pre-production trial.
The double-liner tape may be incompatible with certain plasticized vinyl substrates because plasticizer migration can soften the pressure-sensitive adhesive and reduce dielectric strength at the interface. Combinations with amine-containing surface treatments or uncured silicone release systems may also cause premature crosslinking or adhesion loss. The user should avoid corona treatment of the tape itself; corona treatment is reserved for the target substrate. If the target substrate is an oriented polypropylene film with a low surface energy, a surface treatment level of at least 38 dyne/cm is commonly specified before lamination, but the exact level depends on the adhesive formulation and the line speed. Lamination should be performed within the adhesive’s open time; re-opening after full bond strength has developed may tear the dielectric carrier rather than separate at the adhesive interface, leaving residual adhesive on the target film.
Regulatory compliance documentation should be obtained from the supplier for the specific grade. The tape is generally expected to conform to the applicable requirements of RoHS Directive 2011/65/EU and to the registration and notification obligations of REACH for the substances intentionally added during adhesive coating and liner production. Compliance with food-contact or medical device standards is not automatically conferred by the base tape construction; such applications require grade-specific supplier confirmation. The material is not intended for direct skin contact, and handling should follow standard converting practices for pressure-sensitive adhesives and silicone-coated release liners.
In layer insulation and slot liner lamination, the tape is inserted between the magnet wire winding and the stator core. The dominant electrical stress mode is not a uniform field but a sharp-edge contact where the enameled wire crosses the tape edge. Under such geometry, the dielectric withstand voltage measured in a parallel-plate fixture according to ASTM D149 may not predict the actual breakdown point. Field data from motor manufacturing lines show that edge flashover and abrasion-induced thinning at the slot corner account for a larger share of end-of-line hi-pot failures than the bulk dielectric strength of the carrier. The double liner permits the tape to be die-cut into slot shapes with rounded corners, reducing the stress concentration at the cut edge. After insertion, the second liner can remain in place temporarily during winding and be removed before varnish impregnation; this protects the outer adhesive face from winding tension debris. If the second liner is not removed before varnish cure, the silicone release coating can reduce varnish adhesion and create a void path for partial discharge. The varnish compatibility of the adhesive system should be confirmed by the supplier; published data for this specific configuration is limited.
For electrical insulating tape applications, the product may be evaluated against the test methods in ASTM D1000 or IEC 60454-3, depending on the end-use specification. ASTM D1000 includes test procedures for dielectric breakdown under stretch, adhesion, and electrolytic corrosion; the latter is relevant if the tape is placed adjacent to thin copper conductors. A tape that passes the adhesive and dielectric tests may still fail electrolytic corrosion if the adhesive contains ionic residues; therefore, the end-user specification should include an electrolytic corrosion screen when the tape contacts fine-wire magnet wire or printed circuit traces. Published data for this specific configuration is limited, and the absence of an electrolytic corrosion value on the certificate of analysis should not be interpreted as compliance.
