The designator Saint-Gobain CHR SG23-05(R) identifies a pressure-sensitive tape built on a primary glass-fibre cloth carrier that is coated on one face with polytetrafluoroethylene (PTFE) and carries a pressure-sensitive acrylic adhesive on the reverse face. In the manufacturer’s nomenclature, the numeric suffix connects the nominal backing thickness to the 5 mil class; the parenthetical R denotes a liner or slit roll configuration that must be confirmed against the purchase specification because interleaf materials differ across converting sites. Nominal construction for this grade is a 5.0 mil (0.127 mm) backing and a 2.0 mil (0.051 mm) adhesive layer, producing a total thickness of approximately 7.0 mil (0.178 mm). The term primary glass-PTFE refers to a coated fabric in which the PTFE dispersion is applied and sintered onto the woven glass, rather than a secondary lamination of skived PTFE film to the carrier. This distinction matters in converting: the sintered coating maintains a low coefficient of friction at the exposed face while the glass weave controls stretch and tear. The construction is specified for operations that require a non-stick, low-friction surface, high tear resistance, dimensional stability under web tension, and tolerance for brief contact with heated tooling. In contrast to unsupported skived PTFE film, the woven glass reinforcement restricts elongation and provides a mechanical substrate that can be wrapped, slit, and applied on rotating machinery without the uncontrolled stretching that leads to misregistration. The acrylic adhesive is selected where room-temperature tack to polar substrates and resistance to plasticizer migration are more important than continuous high-temperature bond strength.

What values are reported under PSTC and ASTM methods for SG23-05(R)?

Manufacturer-published control data for glass-PTFE acrylic tapes of this configuration are commonly generated using Pressure Sensitive Tape Council and ASTM test methods. Peel adhesion to stainless steel under ASTM D3330/D3330M is reported in the range of 45 oz/in (12.3 N/25 mm) for a 180° peel angle after a controlled dwell period. Breaking strength measured according to ASTM D3759/D3759M is typically near 150 lb/in (262 N/25 mm) in the warp direction, with elongation at break not exceeding 10%. The low elongation is a direct consequence of the woven glass reinforcement and is the primary reason this tape maintains slit width and edge alignment on automated wrapping machines. Tack and adhesion build are time-dependent; acrylic adhesives in this class may develop maximum peel only after 24 h to 72 h of dwell on the substrate. This behaviour should be factored into rework windows, because an operator may observe lower peel immediately after lamination than during later removal. Dielectric breakdown of the backing under ASTM D149 is thickness-dependent; for a 5.0 mil composite backing, values between 1.5 kV and 3.0 kV are typical in short-term tests, but insulation coordination requires verification on the finished wound component and under the relevant end-product standard. The following table aggregates the typical values used for incoming inspection and process qualification. These values are not design limits; lot-specific certificates of conformance control.

Incoming inspection should compare each lot against the certificate of conformance for thickness, peel, and tensile values. Processes that rely on dielectric strength should not use short-term breakdown alone; contamination and layer count dominate failure risk in wound coils. For converted rolls, edge quality and liner release must be checked on the actual application equipment because bench-top peel cannot replicate the peel speed and angle of an automatic taping head. A mismatch between laboratory stainless steel panels and production aluminium castings is a common source of lot disposition error; the surface finish, cleaning solvent, and dwell period should be fixed in the incoming specification.

On horizontal form-fill-seal machines, the tape is applied to heated sealing bars, side-seal bands, and rotary drum surfaces where polyethylene, polypropylene, or coated paperboard webs are sealed at setpoint temperatures between 120°C and 220°C. The exposed PTFE face reduces film drag and prevents molten polymer from accumulating on the tooling. Because the carrier is glass-reinforced, it resists the tensile load imposed by web tension and the repeated compression cycles of sealing jaws. On impulse sealers, the tape is interposed between the sealing element and the film to allow release after the heating pulse, but the thermal resistance of the glass-PTFE composite must be characterised on the target machine; published data for sealing dwell shift are not universally applicable because bar mass, pressure, and film gauge change the result. A common failure mode on high-pressure jaw sealers is adhesive bleed at the overlap, where the acrylic layer is squeezed under clamp pressure and migrates to the hot face, creating a carbonised deposit that increases coefficient of friction. Overlap position should therefore be located outside the film-sealing footprint where possible. Re-wrapping is triggered by visible fabric fraying, adhesive squeeze-out at the overlap, or a measurable increase in film coefficient of friction above 0.25 when tested under ASTM D1894. The tape should be burnished after application to remove air pockets that create hot spots on the sealing surface.

Electrical insulation and coil-winding operating windows

In slot insulation, interphase barriers, and coil overwrap applications, the glass-PTFE tape is used where the coil winding process imposes puncture and cut-through forces on the insulation. The acrylic adhesive provides room-temperature tack to copper, aluminium, and epoxy-coated conductors, while the PTFE face permits adjacent wires to slide during winding. The woven glass carrier is more resistant to edge cut-through than polyester or polyimide tapes of comparable thickness. Dielectric performance is not solely a function of backing thickness; contamination, adhesive flow, and the number of tape layers determine whether the wound component meets insulation systems standards such as UL 1446 or component requirements derived from IEC 60601-1. Surface resistivity of the PTFE face under ASTM D257 is typically above 10^16 Ω/sq at 50% RH. Because the acrylic adhesive has a lower thermal class than the glass-PTFE backing, continuous operation above 177°C may produce adhesive oxidation and loss of anchorage. The backing itself can withstand short-term exposure to 260°C; published data for partial discharge inception and life endurance for this specific product are limited, so qualification must be conducted on the final coil geometry. When taping rectangular wire, the woven backing can bridge sharp corners below a radius of 2 mm, leaving an air gap that reduces thermal conduction and may lower partial discharge inception voltage under impulse testing.

Release-surface service includes masking during plasma treatment, powder coating, hot pressing, and the lining of chutes and guide rails where sticky adhesives or uncured resins accumulate. In such applications, the glass-PTFE surface maintains a low-energy interface; surface energy of PTFE is typically below 20 mN/m, which limits wetting by most polymer melts and pressure-sensitive formulations. The open weave texture, however, may impart a slight pattern to thick coatings if the tape is used as a smooth release liner substitute. Where optical clarity or mirror-finish replication is required, skived PTFE film tape is preferred because the woven backing leaves a fabric impression under high laminating pressure. In masking for plasma treatment, the glass reinforcement resists tearing when tape is removed after exposure; unsupported PTFE film can tear at die-cut edges and leave fragments inside the chamber. Powder coating operations use the tape to mask bearing seats and threaded holes; the product must be removed before full cure if the powder film bridges over the tape edge, because the acrylic adhesive can lose peel strength above 177°C and leave residue on the metal surface.

When a glass-PTFE acrylic tape should replace a silicone-adhesive or skived PTFE product

Selection between SG23-05(R) and alternative products depends on three variables: adhesive service temperature, substrate surface energy, and required backing conformability. Against stainless steel and aluminium, the acrylic adhesive of SG23-05(R) provides higher initial peel than many silicone adhesives at ambient temperature, and it is less sensitive to plasticizer migration from flexible PVC. This makes the acrylic system preferable for masking PVC extrusions or bundling wires with plasticized insulation. The trade-off is a lower maximum continuous temperature: silicone-adhesive glass-PTFE tapes are generally rated for service up to 260°C, whereas the acrylic adhesive layer of SG23-05(R) should be limited to 149°C to 177°C continuous depending on dwell time. On low-energy substrates such as untreated polyethylene, polypropylene, or silicone-treated surfaces, silicone adhesives may wet more effectively; acrylic adhesion can fall below practical fixture thresholds on such surfaces, so a surface treatment or primer may be required. Compared with rubber-based pressure-sensitive tapes, the acrylic layer has better ultraviolet and oxidative stability and less tendency to leave heavy adhesive residue after heat aging. Compared with skived PTFE film tape, the glass-PTFE backing has higher breaking strength and lower elongation, but it is less conformable on radii below 2 mm and leaves a fabric texture under pressure-sensitive film coatings. Silicone-adhesive glass-PTFE tape remains the preferred product for sealing drums that operate above 200°C continuously, while SG23-05(R) is generally selected for ambient to moderate-temperature operations where the adhesive must resist plasticizer and maintain a clean removal profile. The table below summarises the principal differences.

Before production release, request the safety data sheet and regulatory letter for the exact SKU. Typical documentation for industrial tapes in this class includes RoHS recast (2011/65/EU) and REACH SVHC declarations. For food-contact or medical-device applications, the product is not automatically compliant with FDA 21 CFR or ISO 10993; such end uses require separate approval and extraction testing.

During application, the adhesive requires a clean, dry substrate with surface temperature above 10°C. Condensation on chilled rolls must be removed because acrylic adhesives lose initial tack below 10°C and may transfer residues if the liner is removed too quickly. Solvent compatibility of the acrylic layer is limited; continuous exposure to ketones, esters, chlorinated solvents, or aromatic hydrocarbons can produce adhesive softening, edge bleed, or anchorage failure. For process cleaning, a small-scale trial under production dwell time and wipe frequency is required before any cleaner is introduced. The glass-PTFE backing is chemically resistant to most acids and bases, but strong alkali at elevated temperature can attack the glass fibre at exposed cut edges. The tape should be stored in a humidity-controlled environment below 27°C and 50% relative humidity; shelf life is normally 12 months from the date of manufacture in the original sealed packaging. Rolls should be stored flat to prevent telescoping of slit edges. If liner release force has increased due to moisture uptake, conditioning at 23°C and 50% RH for 24 h may restore unwind behaviour, but this does not recover adhesive that has been plasticized by solvent exposure.