Saint-Gobain CHR SG16-06(R) is a pressure-sensitive tape constructed from a woven glass-fabric reinforcement coated with polytetrafluoroethylene and combined with a silicone pressure-sensitive adhesive. The numeric suffix and parenthetical R in the designation are part of the manufacturer’s construction and regulatory coding; the R suffix is commonly associated with restricted-substance documentation, although lot-specific verification against the supplier’s certificate of compliance remains required. The product is intended for high-temperature release, electrical insulation, masking, and sealing operations where the backing is required to maintain dimensional stability during short excursions above the continuous rating of unreinforced PTFE films. Representative class data for glass-PTFE/silicone composites place the continuous service temperature at 260 °C with intermittent exposure to 288 °C; low-temperature flexibility is retained to approximately -73 °C. Published values for the exact SG16-06(R) thickness and peel performance should be drawn from the Saint-Gobain technical data sheet for the controlling revision, because coating-to-coating lot variation and adhesive coat-weight tolerance affect final properties.

In production use, the tape is applied as a protective wrap on sealing bars, as edge masking on electrostatic powder-coating fixtures, and as an interlayer dielectric in coil and transformer assemblies. The glass fabric restricts elongation and prevents the cold-flow deformation that characterises skived PTFE carriers. The outer PTFE face provides release from epoxy, polyurethane, and silicone molding compounds; the silicone adhesive maintains tack at elevated temperatures but is not classified as a structural bond.

How do peel, shear, and dielectric responses compare across silicone adhesive cure states?

Peel adhesion of silicone transfer adhesives on this tape class is typically measured at 180° peel against stainless steel under ASTM D3330/D3330M using a dwell time of 20 min and a test speed of 300 mm/min. Class data for glass-PTFE/silicone tape generally fall from 4.5 N/25 mm to 6.5 N/25 mm at room temperature. After conditioning at 204 °C for 24 h, peel may rise initially because of increased adhesive wet-out and then decline if oxidative degradation of the dimethylsiloxane network becomes dominant. Shear holding power at 100 °C under a 1 kg static load is typically reported as greater than 60 min on stainless steel; published data for this specific configuration should be confirmed through the manufacturer.

Dielectric strength is determined under ASTM D149 or IEC 60243-1 using short-time testing on as-received specimens. Commercially available glass-PTFE laminates of approximately 0.15 mm total thickness commonly exhibit breakdown strengths in the range 3.0 kV to 4.5 kV, with the exact value dependent on the degree of PTFE void-fill in the woven glass interstices. Surface resistivity above 10^12 Ω/sq at 25 °C and 50% relative humidity is typical for the PTFE face; contamination by conductive dust or silicone release agents from adjacent operations can reduce surface resistivity by several orders of magnitude.

The adhesive cure state is significant because under-cured silicone PSA will exhibit high initial tack but poor high-temperature shear, while over-cured adhesive may become brittle and exhibit edge lift at low temperature. The production process for the tape class employs a controlled thermal cure and volatile stripping step, with residual solvent or low-molecular-weight siloxane content maintained below the threshold specified in the supplier’s release specification. On electrostatic powder lines, excessive free silicone contamination is a known source of paint adhesion defects; therefore, the tape should be conditioned and any transferred low-molecular-weight species removed before coated parts enter the topcoat oven.

Surface preparation influences bond formation more than adhesive temperature rating. Stainless steel and chromium-plated fixtures are degreased with 99% isopropanol or methyl ethyl ketone, wiped with a lint-free cloth, and air-dried for 30 s to 60 s before tape application. The tape is applied with a hard-rubber laminating roller at a load of 2 kg to 3 kg and a travel speed not exceeding 10 mm/s for initial wet-out. A pressure dwell of 24 h at 20–25 °C before first thermal ramp improves adhesive anchorage on grit-blasted steel. Production lines that bypass this dwell and immediately expose the tape to radiant heat in a powder-coating oven at 200 °C frequently observe edge lift because the adhesive has not established sufficient peel-resistant contact against the surface profile.

Sharp edges with radii below 0.5 mm are a known failure site because the glass fabric retains tensile stress through the PTFE coating and can transmit the bending moment to the adhesive line. A double-layer fold-over at the edge or a metal shim termination is used where continuous coverage is required. On production-scale coating and slitting lines, the tape is typically converted into log rolls and side-trimmed to the customer width using through-heat-hardened circular blades. Slit edge quality is relevant because a raised glass filament at the edge can collect powder coating and create a visible line after demasking. Industrial converters require edge burr or fiber protrusion to be controlled to less than 0.1 mm; specifications are checked by optical comparator at 10× magnification. The product is therefore specified not only by bulk thickness but also by edge cleanliness where masking tolerances are below 0.5 mm.

Observed field failures on powder-coating lines include complete tape lift-off at the leading edge on parts entering a convection oven at 204 °C within 90 s of application; adhesive residue on chromium-plated fixtures after thermal cycling; and entrapped solvent blistering when the tape was applied over a wet solvent film. These failure modes are avoided by specifying a clean dry substrate, roller pressure, and if practical a 24 h dwell. Silicone adhesives have a high coefficient of thermal expansion relative to steel; rapid heating can create interfacial shear stresses that exceed the initial peel resistance before adhesive flow has occurred.

Silicone transfer is a separate concern. Low-molecular-weight siloxane fractions can migrate under heat and contaminate surfaces for subsequent painting or bonding. Quantitative extraction with gas chromatography after thermal conditioning at 150 °C for 24 h is used by manufacturers to characterise volatile content. Users performing adhesive bonding after tape masking should conduct a water-break-free test or surface energy check with dyne solutions in accordance with ASTM D2578; a drop in surface energy below 38 mN/m on aluminum often indicates silicone contamination.

When masking stations transition from polyimide or acrylic-glass tapes to PTFE-glass laminates

The principal operational difference is observed in elongation and dimensional stability. Polyimide/silicone tapes at 0.05 mm to 0.08 mm thickness provide higher puncture resistance and smoother profile on tight diameters, but they do not offer the same degree of conformability on irregular castings. Acrylic-adhesive glass tapes reduce cost but are limited to continuous operating temperatures below approximately 150 °C; acrylics lose peel strength above this threshold and can carbonise if the line overshoots during cure. A silicone rubber-based self-fusing tape can exceed 260 °C only if the carrier is not mechanically loaded; unreinforced rubber tapes elongate under tension and are unsuitable where dimensional control is required.

Compared with a skived PTFE/silicone tape, the woven-glass carrier in SG16-06(R) restricts permanent elongation under load. That difference matters when a masking strip is tensioned across a long fixture or wrapped over a straight edge; unreinforced PTFE can neck down irreversibly and recover incompletely on cooling, leaving a gap. The glass reinforcement also reduces the tendency of PTFE to cold-flow under clamp pressure. However, the same reinforcement reduces the ability of the tape to stretch over compound curvature; a skived PTFE tape is preferred where the application requires more than 100% elongation.

For continuous exposure above 150 °C, the silicone adhesive version is selected because acrylic PSA ester linkages undergo hydrolysis and oxidative chain scission, causing residue and odour. Below that threshold, an acrylic glass-cloth tape may provide a higher initial tack to stainless steel and lower unit cost. SG16-06(R) is therefore specified when oven settings exceed the acrylic limit or when the tape must survive incidental contact with heated sealing bars. Table 1 provides representative class-level comparisons. The values are not lot-specific guarantees for SG16-06(R) but are drawn from published industrial data for tapes of equivalent construction.

In electrostatic powder-coating applications, the glass-PTFE/silicone construction reduces coating build-up on the tape face because the PTFE surface lowers surface energy and facilitates mechanical knock-off after cure. However, this same low-energy surface prevents paint adhesion; masking edges must be designed so that the powder does not wrap around the tape edge and leave an unbonded seam after demasking. Tape remnants or silicone transfer can be visual defects in a subsequent clear coat. Production trials on aluminum wheel lines with a 200 °C cure oven have shown that adhesive transfer is minimized when the tape is removed at a peel angle of 90° while the part is below 60 °C. Published data for this specific configuration on other coating chemistries is limited.

Electrical insulation applications impose a different requirement: the tape must survive thermal aging without losing dielectric strength. Specimens are often aged for 168 h at the rated temperature and then subjected to ASTM D149 dielectric strength tests. Glass-PTFE/silicone tapes intended for class H or class C insulation are evaluated for thermal endurance, because insulation life is a function of the degradation kinetics of the glass fabric size, the PTFE matrix, and the silicone adhesive. The glass fabric in the product remains the dominant contributor to tensile modulus; PTFE provides environmental sealing and chemical inertness; the silicone adhesive may become brittle after prolonged exposure above the continuous rating.

In coil winding, the tape may be used as layer insulation or outer wrap. The adhesive must not generate corrosive by-products in contact with copper or enamelled wire. Silicone adhesives are generally low in chloride and sulfur; specifications for class F and class H electrical insulation often require halogen content not exceeding 100 ppm and sulfur not exceeding 100 ppm. The user must request ion chromatography data from the manufacturer because film data alone does not establish electrical compatibility under partial discharge. Partial discharge inception voltage is not a routine datasheet value; it is measured under IEC 60343 if the intended use includes inverter-fed motor windings.

Tensile strength and elongation are determined on 25 mm wide specimens using a universal test machine with an initial jaw separation of 100 mm and a rate of 300 mm/min. The measured tensile modulus is dominated by the glass fabric; variation in fabric style and greige lot can produce batch-to-batch differences of ±10% in tensile strength. Elongation values below 5% are typical because the PTFE matrix is fully sintered and the weave is set. The processing window is governed by the adhesive glass-transition and silicone network integrity rather than by the backing alone. Silicone PSAs are based on dimethylsiloxane gum reinforced with MQ resin. Peel maxima can shift with post-cure. The manufacturer controls coat weight within a specified window because peel strength is directly proportional to adhesive thickness only up to a critical thickness; above approximately 0.05 mm adhesive thickness, cohesive failure dominates and peel becomes less dependent on coat weight.

PTFE is resistant to many solvents; however, the silicone adhesive is not. Chlorinated solvents can extract low-molecular-weight siloxane; toluene, xylene, or n-methyl-2-pyrrolidone can soften silicone. Production exposure to ester-based printing solvents above 40 °C may cause edge lifting. Alkali cleaners above pH 10 at elevated temperature attack glass fabric, particularly at cut edges; acid environments are generally less aggressive to the glass but can corrode steel substrates under the tape if moisture is trapped.

Shelf life for the product is generally 12–18 months from date of manufacture when stored in original packaging at 18–25 °C and 40–60% relative humidity. High-humidity storage is detrimental only if the glass fabric is not fully sealed; moisture absorbed at the edges can vaporise during thermal curing and cause blisters. Rolls should be stored away from direct UV and ozone sources because silicone adhesives are vulnerable to ozone-induced chain scission.

The compliance status of SG16-06(R) is controlled by the supplier’s material declaration and lot certificate. Table 2 lists the provisions commonly cited in industrial specifications for the product.

The product is not formulated as a direct food-contact adhesive; PTFE resin in the backing may be evaluated under 21 CFR 177.1550, but the silicone adhesive and glass fabric size require separate compliance assessment for specific food-contact uses. Prolonged contact with low-molecular-weight ketones, esters, or chlorinated solvents can swell the silicone adhesive and reduce peel at elevated temperature. The PTFE surface is inert to most mineral acids and alkalis, but strong alkali at high temperature can attack the glass fabric at exposed edges. The tape should not be exposed to conditions above 260 °C for extended periods in the presence of air, because oxidative degradation of the adhesive can lead to hardening and residue withdrawal. The user is responsible for process qualification using production-scale equipment, including oven temperature variation, mask geometry, and coating-line dwell conditions.