During thermal curing of solventless silicone release coatings on biaxially oriented poly(ethylene terephthalate) and glassine webs, the exposed edges of the web must be masked to prevent edge curl, coating pickup on the reverse side, and wound-roll blocking during downstream slitting. CHR M98 is applied on these lines where the silicone pressure-sensitive adhesive is required to anchor to surfaces that already carry a cured or semi-cured silicone release layer, a condition that causes most acrylic adhesive tapes to lose peel force within 1–2 m/min of unwind contact. The polyester film backing provides the stiffness needed to hold a straight edge over the coating gap without adhesive stringing into the platinum-catalysed silicone fluid. Application is carried out after corona treatment to raise the substrate surface energy to at least 38 mN/m when masking untreated polyester; glassine and clay-coated kraft typically require only a dry-lint wipe or a wipe with reagent-grade isopropyl alcohol followed by 30 s of flash-off. The tape is positioned with a 3–6 mm overhang onto the coating bed so that the liquid silicone does not contact the web back-side. Cure ovens for solventless release coatings commonly operate at 150–180 °C with dwell times of 20–60 s. During this interval the tape remains dimensionally stable, and the silicone adhesive does not generate volatile condensate that deposits on oven walls or coating rolls. A known process failure occurs when tape is exposed above the current Saint-Gobain datasheet service limit, where additional crosslinking of the silicone adhesive can produce brittle residue at the media edges after unwind. The same failure is observed if the tape is applied to a surface contaminated with unreacted silanol fluid, because the adhesive wets the fluid layer rather than the substrate. Compliance in this segment is governed by the host product; release-liner manufacturers use the tape under REACH EC 1907/2006 Article 33 for SVHC communication and under RoHS Directive 2011/65/EU Annex II where the liner enters electronic or medical device packaging. Finished products include release liners for graphic films, wound-care island dressings, graphite sheet carriers, and pressure-sensitive label stock. For medical packaging, the final liner must meet ISO 11607 requirements for terminally sterilised barrier systems; the tape alone does not confer that status.

Where Butt Splicing of Silicone-Coated Release Liners Demands Roll Compression

Splicing of silicone-coated release liners differs from standard paper splicing because the low surface energy of the silicone layer, typically 24–28 mN/m, prevents conventional acrylic adhesives from reaching sufficient contact to survive calender or slitter tension. The silicone adhesive on CHR M98 can establish an interface with the release surface, but only if the splice is mechanically compressed before the web resumes speed. A butt splice is produced with a top-side strip and a bottom-side strip, each cut to an overlap length of 50–75 mm for roll widths above 1,500 mm. The upper and lower strips are aligned within ±0.5 mm at the edge, and the splice is passed through a roll compression station fitted with a silicone rubber nip at Shore A 70–80 per ASTM D2240. Dwell under compression is usually 1–2 s. At this point the adhesive has not developed full shear strength; a waiting period of at least 5 min at 23 °C is specified before the line returns to full speed, and final shear build can require 24 h depending on the release surface chemistry. The overlap dimension is selected so that the maximum unwind tension at the accumulator does not exceed 50% of the tape shear adhesion value reported on the current CHR M98 datasheet when tested per ASTM D3654/D3654M. A common failure mode is splice telescoping after manual application because the operator did not seal the trailing edge at the roll core; a second 10–15 mm tape tab across the core side prevents this. This splicing method is used on release-liner finishing lines, coaters for industrial double-sided tapes, and slitter rewinders handling medical hydrocolloid dressing carriers. The finished continuous rolls are then converted into liner components for label stock, exterior signage films, and silicone-coated paper release bases.

What Limits Thermal Exposure During Powder Coating Masking?

The upper process limit in powder coat masking is governed by backing shrinkage and adhesive oxidation rather than by instantaneous peel loss. Polyester film backings retain mechanical integrity during short powder cure cycles, but the exact continuous service rating for CHR M98 must be read from the current Saint-Gobain technical datasheet; industrial silicone-adhesive polyester tapes are commonly evaluated at 180 °C for 15–30 min cure dwells, while long-term continuous exposure above the rated value can cause edge lift. Masking is applied to threaded bosses, bearing journals, grounding pads, dowel holes, and machined reference surfaces on steel or aluminium parts after solvent degreasing and before phosphate or zirconium conversion coating. The tape edge is pressed with a hard rubber roller to exclude pretreatment bath ingress. If the part enters an acidic phosphate bath at 50–60 °C and then passes through a powder cure oven at 180–200 °C, the polyester backing remains stable provided the cure does not exceed the supplier-rated maximum. Silicone adhesive resists water and dilute phosphate solution, but a masked part should not be re-baked in the same cure oven after the first heat cycle. Re-baking at 220 °C or higher can oxidise the adhesive-polyester interface and cause cohesive failure during removal. Adhesive transfer in this application is most often caused by pre-existing silicone contamination on the workpiece from mould-release agents or by dragging the tape edge across the part surface with excessive finger pressure. Removal is performed after the part cools below 50 °C; hot peeling can leave adhesive tracks on the cured powder surface. RoHS compliance under RoHS Directive 2011/65/EU is relevant where the coated article is placed on the EU market as electrical or electronic equipment; the tape must not introduce lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE above the Annex II limits. Finished articles include powder-coated enclosures, electrical cabinets, automotive brackets, and architectural metal fittings. The tape is not a substitute for single-use polyester masking plugs in high-pressure wash booths where the tape edge may be lifted by spray impingement.

Autoclave cure of prepreg laminates at 120–180 °C and 0.6–0.7 MPa gauge pressure requires that auxiliary tape used to seal thermocouple vacuum bags, mask mould flanges, or secure breather strips does not become a source of silicone transfer or bag-side contamination. On epoxy and aluminium tooling, CHR M98 is removed after a single autoclave cycle and before reapplication of mould release agent. Repeated cycling without cleaning can build silicone residue at the tape boundary, which later interferes with paint adhesion or structural adhesive bonding on the trim line. The tape is applied to a solvent-wiped tool flange under low tension, with corner overlaps of 10–15 mm, and pressed with a hard rubber roller to eliminate air channels under the vacuum bag edge. During cure, the polyester backing remains dimensionally stable at standard prepreg cure temperatures, but exposure above the datasheet limit can cause edge lift and loss of vacuum integrity. A specific failure mode in autoclave use is adhesive transfer to the tool surface when the tape is left in place for multiple cure cycles or when the tool retains hot silicone release agent from previous operations. The vacuum bag is therefore sealed against the tape back-side rather than against the adhesive face. For spacecraft or optical mould transit applications, outgassing must be evaluated separately per ASTM E595; CHR M98 is not automatically qualified as a low-outgassing product. Finished composite parts include CFRP automotive body panels, aerospace interior panels, wind turbine shear webs, and autoclave-cured engine nacelle subcomponents. Compliance under REACH EC 1907/2006 applies to the tape as an article, and the tape must not introduce prohibited substances into the tooling release system or into the composite surface.

When Electrical Coil Wrapping Uses Silicone-Adhesive Polyester Tape

Polyester film is known for high dielectric strength per unit thickness, but CHR M98 is a pressure-sensitive tape with silicone adhesive and is not by default a listed primary insulation tape. If used in dry-type transformer cores, solenoid coils, or fractional-horsepower motor windings, it serves as an outer wrap, lead bundle tie, phase identification marker, or temporary holding layer, not as sole barrier insulation between windings. The tape is applied with 30–50% overlap under tension not exceeding 20% of the backing tensile strength shown on the current CHR M98 datasheet. Long-term thermal capability of polyester backings is determined by ageing under IEC 60216-1; general-purpose PET films are often class B at 130 °C unless a specific class rating is assigned. Silicone adhesive can tolerate higher short-term temperatures than the polyester backing, so the backing thermal class limits the coil application. A common failure mode is edge lifting after varnish impregnation because the tape was not burnished before the coil entered the varnish tank. Another failure occurs when the tape is used as primary interlayer insulation and subjected to partial discharge; the silicone adhesive layer is not designed as a void-free dielectric barrier. Electrical equipment compliance may require IEC 60454-3 for pressure-sensitive adhesive tapes for electrical purposes or UL 510 for insulating tape; these ratings must be confirmed for CHR M98 before use in listed devices. Finished articles include dry-type transformer lead anchoring, solenoid actuators, stator coil outer serves, and commutator protection during varnish cure. The tape is not recommended for direct contact with hot-spot temperatures above the polyester thermal class, even if the silicone adhesive appears intact.

A Silicone Foam Casting Line Tracks with CHR M98

In continuous silicone foam casting, liquid silicone precursors are knife-coated onto a moving release liner or steel belt and cured in staged ovens between 120 °C and 180 °C. CHR M98 is used to mask belt edges, join release liner segments, and secure deckle side rails on the casting deck. Because both the backing and adhesive are polyester-silicone systems, an edge fold-over does not introduce nitrogen- or sulfur-containing contaminants that would inhibit platinum-catalysed silicone cure. The liner splice tape must resist silicone oil bleed and anchor to the release surface. Surface energy on a silicone release liner is often too low for mechanical interlock; increasing the tape overlap to 40–60 mm and adding a roller pass improves contact. The tensile load is distributed across the full web width, and the splice is held at 23 °C for 5 min before the casting line returns to full speed. If the liner is coated with a fluorosilicone release layer, adhesion may fall below process requirements; published data for this specific configuration is limited, and a peel test per ASTM D3330/D3330M should be run before installation. Another known failure is edge lift at the deckle rail because the tape was applied over uncured silicone oil that had migrated from the foam precursor; the deckle must be wiped dry before tape placement. Compliance for industrial foam manufacturing is covered by REACH EC 1907/2006 and by the site’s occupational exposure assessment for silicone thermal breakdown products. Finished products include silicone foam gasket sheets for HVAC, medical positioning pads, automotive weatherstripping cores, and cushioning inserts for electronic enclosures. The tape is not used as a food-contact article unless the specific CHR M98 grade is explicitly authorised for that end-use.