Saint-Gobain CHR 2255-2 is a pressure-sensitive adhesive tape constructed from a high-modulus polytetrafluoroethylene film backing and a silicone adhesive system. The product is supplied in roll form for release surfaces, heat-sealing equipment, and electrical insulation applications where low surface energy and sustained thermal tolerance are required. The high-modulus PTFE backing is oriented during film forming rather than skived from billet stock, which increases machine-direction tensile modulus and reduces elongation at break relative to conventional skived PTFE tapes. The following table summarizes distributor-published nominal values; lot-level certification is required for critical manufacturing specifications.

On rotary jaw heat sealers running low-density polyethylene film at 150–190°C, CHR 2255-2 is installed with the silicone adhesive against the jaw and the PTFE surface toward the polymer melt. The exposed PTFE surface has a surface energy near 19 mN/m, which prevents molten polyolefin transfer without a secondary release coating. The silicone adhesive retains room-temperature peel after intermittent exposure to 260°C. Room-temperature adhesion to stainless steel is reported at 25 oz/in when tested according to ASTM D3330. Thermal cycling of a taped jaw from 30°C to 205°C over an 8-hour shift can induce adhesive ooze at the tape edges if wrapping tension exceeds approximately 15 N/cm. Published cycle-life data for this specific heat-sealing configuration are limited; replacement intervals on production lines are therefore governed by visual inspection for backing scuffs, edge lift, and transfer of sealant residue.

The oriented PTFE film tolerates repeated clamp compression better than a standard skived PTFE tape of the same total thickness. At seal-bar hydraulic pressure of 0.4–0.7 MPa, the high-modulus backing maintains flatness and reduces fold-over at the jaw shoulder. Converting should be performed with carbide slitter blades rather than razor steel, because edge scoring of the PTFE can reduce dielectric strength and initiate tear propagation along the machine direction. The silicone adhesive does not require heat activation, but a minimum dwell time of 24 h at 21–27°C after application increases ultimate peel force to metal substrates by allowing silicone wet-out. Early thermal loading before full dwell can produce edge tunneling on crowned rolls.

Why Does Silicone Adhesive Chemistry Limit Solvent Wipe-Down Protocols?

Silicone pressure-sensitive adhesives swell in aromatic hydrocarbons, ketones, and chlorinated solvents. Cleaning the exposed PTFE face with methyl ethyl ketone, toluene, or methylene chloride can cause solvent ingress at the cut edge and reduce adhesive anchorage below the supplier-reported 25 oz/in peel value. Non-aggressive aliphatic hydrocarbon or 2-propanol is specified for routine surface cleaning. In coating lines handling methylene chloride or dimethylformamide, the tape edge should be protected by a fluoropolymer overlaminate. The PTFE backing itself is substantially inert to these solvents, so failure appears at the adhesive-substrate interface rather than as backing degradation. If a taped roll must be wiped with a high-flashpoint ester blend, a trial patch under production shear and temperature is required; published data for specific solvent blends on this product are limited.

In cast-film and blown-film extrusion, CHR 2255-2 is applied to die lips and collapsing-frame contact points where melt deposits are undesirable. The low surface energy PTFE face prevents low-density polyethylene melt adhesion at die lip temperatures up to 230°C. Because the silicone adhesive is thermally stable at these temperatures, the tape does not char or transfer adhesive to the melt. On polished chrome die lips, the substrate should be degreased with 2-propanol and dried with filtered compressed air at less than 0.1 MPa. If the die lip surface temperature exceeds 260°C, the adhesive begins to harden and the backing may develop localized thermal deformation; published data for this boundary condition are limited, and a ceramic-coated die should be used for higher-temperature resins.

In low-voltage stator coil insulation, the tape is wrapped in half-lap configuration at a controlled tension of 2–5 N. A single layer of CHR 2255-2 is supplied with a dielectric strength of 5.0 kV per ASTM D149. The actual insulation value after insertion into a stator slot depends on layer overlap, wire lacquer thickness, and slot-cell corner radius; it does not scale linearly with the number of wraps because air gaps at overlap lines become partial-discharge initiation sites. When used under vacuum-pressure impregnation with epoxy or unsaturated polyester resins, the silicone adhesive is generally compatible with bake schedules of 150–180°C, but resin adhesion to the non-porous PTFE surface is minimal. The tape should therefore be specified as interlayer insulation, not as an outer conducting semi-conductive layer.

Silicone fluid contamination is a known failure source on motor manufacturing lines. If the same work cell handles silicone release agents or silicone-based conformal coatings, mist deposition can reduce tack below process acceptance values. A control plan separating silicone adhesive tape dispensing from spray mold-release operations is required at relative humidity above 60%. Rolls should remain in vapor-barrier packaging at 21–27°C and 40–60% RH until use; condensation on cold adhesive surfaces creates localized dewetting that cannot be corrected by re-drying.

When High-Modulus PTFE Replaces Skived Film in Tensioned Roller Wrapping

The principal difference between CHR 2255-2 and a conventional skived PTFE tape with silicone adhesive appears in machine-direction tensile modulus. Skived PTFE tape typically has higher elongation and lower tear resistance, which can cause neck-in and gauge variation when it is wound at high tension onto coating rolls. The oriented, high-modulus backing in CHR 2255-2 resists elongation, making it suitable for tension-controlled wrapping of idler rolls in adhesive coating or laminating lines. In a converting line with web tension of 10–35 N/cm, the taped roll shows less thickness reduction at the wrap edge than skived PTFE. The smoother surface of the oriented film also reduces transfer of pressure-sensitive adhesive micro-particles to the web. Compared with PTFE-coated glass cloth tape, CHR 2255-2 has lower conformability around knurled or perforated rolls, but it presents a smoother release topography and a thinner lap seam of 0.0045 in total thickness. Compared with acrylic adhesive PTFE tape, the silicone adhesive extends the upper continuous service limit to 260°C but yields lower initial peel on low-energy polypropylene substrates.

Roller wrapping should be completed with a continuous helix of 20–50% overlap, avoiding transverse butt seams that create a groove at high line speed. The liner is removed under low tension, and the roll is cleaned with 2-propanol before wrapping. The tape edge should not be exposed to knife cuts that penetrate the backing; a shallow scoring depth of less than 0.001 in (0.025 mm) is acceptable only at the trim station, not on the working face.

For composite layup release on aluminum tooling, CHR 2255-2 is occasionally specified as a release ply when an optically smooth surface is required. The PTFE backing resists adhesion of epoxy, bismaleimide, and cyanate ester resins up to 260°C, but the silicone adhesive can leave residue on the tool if the tape is dwelled at high temperature for more than 4 h. Autoclave processes using 316 stainless steel tools should include a post-cure wipe with 2-propanol to remove any silicone transfer. On tools with nylon vacuum bagging, the tape can be used as a batten to protect thermocouple lead paths; however, silicone adhesive bonding to nylon film is weaker than to metal, and mechanical fastening with flash tape may be required. The product is not intended for direct contact with uncured silicone rubber or with amine-based mold releases because those materials plasticize the adhesive.

The high-modulus PTFE film also distinguishes CHR 2255-2 from PTFE-coated glass cloth carriers in electrical applications. Glass cloth-backed tapes provide higher tear resistance and conformability around sharp slot radii, but their woven reinforcement introduces a coarser surface and greater total thickness. CHR 2255-2 provides a thinner profile and smoother surface for layer-to-layer insulation, though it is less suited to irregular coil shapes. In applications requiring flame retardance or higher abrasion resistance, a polyimide film with silicone adhesive may be selected instead, although it lacks the low-friction release face of PTFE. The selection between these alternatives should be based on the dielectric withstand test method, the geometry of the substrate, and the maximum continuous thermal load during manufacturing.

Storage and handling constraints are part of the product specification rather than an ancillary concern. Rolls should not be stored on end, because silicone adhesive systems are subject to slow flow under unbalanced compression; core-side adhesive migration can create caliper variation and unwind noise. If rolls have been exposed to freezing temperatures during transport, they should be conditioned at 21–27°C for 24 h before slitting. Slitting blades should be inspected for burrs before each lot, and tension should be held below 20 N/cm to prevent stretch of the oriented backing. These limits are standard for thin high-modulus PTFE tapes and are not specific to a single converting line.

The silicone adhesive side is sensitive to low-molecular-weight plasticizer migration from flexible vinyl substrates. When CHR 2255-2 is applied to plasticized PVC rollers or wire insulation, plasticizer migration can soften the adhesive and reduce shear holding power. For that reason, the product is generally not recommended for direct adhesion to heavily plasticized vinyl without testing under the intended service temperature. On rigid polyimide, stainless steel, chrome-plated steel, and degreased aluminum, adhesive performance is more predictable and corresponds more closely to the published ASTM D3330 peel value. Where the substrate includes a fluoropolymer or silicone-based nonstick coating, initial adhesion is materially reduced; published data for this specific configuration are limited, and mechanical fastening or abrading the substrate may be required.

Chemical resistance of the backing should not be confused with resistance of the adhesive interface. The PTFE backing withstands most industrial chemicals, including concentrated acids, alkalis, and oxidizing agents, except molten alkali metals and elemental fluorine at elevated temperature and pressure. The silicone adhesive, however, is swollen by hydrocarbon oils and chlorinated cleaning agents. In chemical processing roll applications, the exposed PTFE surface may be wiped with mineral acid solutions, but edge sealing is required to prevent capillary ingress into the adhesive. The tape should not be used as a primary corrosion barrier for flanges or pipe wraps, because its pressure-sensitive adhesive is not designed for immersion service.

In flexible packaging heat sealing, the product is often compared to a standard PTFE-impregnated glass cloth tape with silicone adhesive. The glass cloth tape provides better puncture resistance and is easier to apply on curved seal jaws, but its thicker seam can mark thin film webs. CHR 2255-2 leaves a lower seam profile and creates a smoother polymer contact surface, which is advantageous on high-clarity film lines. The trade-off is lower tear resistance in the machine direction; once a nick initiates in the high-modulus PTFE backing, tear propagation can be rapid. Operators should inspect each roll for nicks after slitting and during changeover. A visual inspection standard of 0.5 mm maximum edge defect is common on converting lines, though the exact limit depends on downstream sealing pressure and film thickness.