3M 910 Repulpable Forms-Splicing Tape is a single-coated, paper-backed pressure-sensitive joining tape used primarily for butt splicing of lightweight continuous forms stock on roll-fed presses and collators. The construction combines a flat, repulpable paper backing with a water-dispersible pressure-sensitive adhesive. Both components are intended to break down under conventional alkaline paper repulping conditions, allowing spliced waste, trim, and reject forms to be returned to the mill furnish without generating the macroscopic film residues typical of polyester or polypropylene splicing tapes. This repulping characteristic is the primary differentiator from general-purpose film-backed or solvent acrylic splicing products, which exhibit higher retained screen rejects and can contribute to macrostickies in deinked pulp.

Target paper grades include wood-free forms bond, register bond, carbonless paper, and lightweight coated stock. In these applications, the splice seam must survive web acceleration through turning bars, sprocket-pin feed, punching, perforating, folding, and printing units while maintaining a low enough caliper step height to avoid mechanical bounce. The tape is typically applied as a butt splice, with the expiring roll tail and the new roll leading edge cut square, butted, and secured by the single-coated tape. Some press configurations use tape on one side of the web; others require a second tape on the reverse side where the web path imposes high bending loads.

The single-coated tape is supplied in slit rolls for manual and automatic splicers. Roll widths and lengths are determined by the splice head jaw width and the converting press rewind stand. Because butt splicing requires the tape to bridge the seam without overlapping the web edges unnecessarily, edge slitting tolerance is a practical factor. The product is specified for forms-weight paper rather than corrugated or heavyweight paperboard; for heavier grades, a higher-caliper repulpable tape with greater tensile strength is normally selected.

How Is Repulpability Quantified After Slushing and Screening?

Repulpability is evaluated by slushing the tape in a laboratory pulper and screening the re-pulped furnish. The relevant method for pressure-sensitive tape constructions is TAPPI/ANSI T 274, with PTS-RH 021/97 used in some European mill specifications. Laboratory acceptance criteria generally focus on visible or instrumental screen rejects after the repulped stock is passed through a slotted screen or formed into handsheets. Because both the paper backing and the adhesive are designed to be water-dispersible, the 3M 910 splice tab is expected to break into dispersed paper fiber and adhesive particulates rather than remaining as a continuous film or large macrosticky mass. Mill-specific acceptance thresholds vary by fiber furnish and stock preparation design.

When Turret Splicers Operate Under Rapid Web Acceleration

During automatic splice cycles, the new roll accelerates from zero to press speed in a short dwell. The splice is subjected to combined peel and shear loading as dancer rolls change position and web tension transfers from the expiring roll to the new roll. The 3M 910 tape is specified for forms-grade papers where the splice must not impose a stiffness mismatch that causes web flutter or tearing immediately downstream of the splicing head. In field use on rotary collators, the primary failures are edge lift, tape touchdown on idlers, and step-height-induced web snap, rather than pure tensile failure of the tape. Therefore, adhesion testing on the actual paper grade and at operating web tension is more diagnostic than tensile strength data alone.

On high-speed continuous forms presses, the splice must pass through punching and perforating cylinders without interfering with pin feed registration. A splice tab that is higher in caliper than the base paper can lift the web off the pin feed, causing registration errors and jam-ups. The low-caliper paper backing of 3M 910 is one of the design features for this service, although the exact caliper value for a given roll lot should be obtained from the manufacturer’s certificate of analysis. Cutting the expiring tail and incoming leading edge with a square, clean cut before splicing reduces lateral curl and edge fiber lift, which are common sources of splice peel initiation.

Lot-to-lot variation in paper backing caliper and adhesive coat weight exists within manufacturing tolerances. For critical pinch points on forms collators, incoming lots should be measured for caliper using ISO 534 and for peel adhesion on the actual paper grade. Field experience suggests that lot-to-lot variation is less visible on uncoated forms bond but may appear when splicing siliconized or high-slip coated papers.

Adhesive Transfer, Edge Lift, and Splice Step Height

Adhesive transfer to steel idlers, print blankets, or folding rollers is a failure mode when a splice remains in a heated or high-pressure zone after the tape has softened, or when the web is stationary under tension. The water-dispersible adhesive is designed for quick grab and shear resistance at room-temperature splicing conditions, but the product is not formulated as a high-temperature splicing tape. When a splice is exposed to heated drying units or infrared dryers on a forms press, the adhesive may soften beyond its intended service range. Specific heat-resistance values published for this configuration are limited; trials should be conducted on the actual press if the splice will pass through heated zones.

Edge lift at the butt seam is typically initiated by paper curl, dust, or anti-setoff spray powder. Spray powder reduces adhesive wet-out on the paper surface, lowering peel force and increasing the probability of flap open. On carbonless forms, microcapsule coatings may act as a release plane; peel adhesion should be measured on each coated face rather than on a single representative substrate. Automatic splicers with calibrated nip rollers apply more uniform pressure than manual hand-held dispensers. When manual splicing is used, a hard-rubber roller should be passed over the full seam to reduce entrapped air pockets at the paper-tape interface.

Compared with non-repulpable film-backed splicing tapes, the 3M 910 construction converts from a continuous splice tab into dispersed fiber and adhesive particles during repulping. This behavior reduces the load on pressure screens and deinking flotation cells, but it does not remove the requirement for contaminant monitoring. Dispersed adhesive material can still contribute to anionic trash and may affect retention aid demand or deposition behavior. Mill trials with actual spliced broke are required to quantify these effects; a laboratory repulpability test alone does not predict fine-particle deposition on paper machine fabrics.

Stock Preparation Does Not Treat Dispersed Adhesive as Inert Fiber

Stock preparation systems operate at pH levels and temperatures that vary by mill. In alkaline deinking lines, the paper backing of 3M 910 is expected to disintegrate into pulp, and the water-dispersible adhesive is expected to break into small particles rather than remaining as a continuous film. The degree of dispersion depends on pulping consistency, temperature, pH, and residence time. Cold repulping may require longer pulping time for complete fiber separation, while high-consistency pulping at higher temperatures accelerates dispersion. Mill-specific validation should include handsheet formation per ISO 5269-1 and screening across slotted screens representative of the mill’s approach flow.

One process conflict in deinking lines is the same dispersibility that enables repulpability: if the spliced reel is stored in a humid environment or the splice passes through wet processing, the adhesive can begin to soften and lose splice strength before the splice reaches the repulper. The product is therefore not intended for splicing webs that will be exposed to liquid water or high-humidity processing between the splice point and the final dry conversion step. This operational boundary distinguishes the 3M 910 forms-splicing tape from moisture-resistant film-backed tapes, which may survive humid environments but create repulpability problems.

The product is not a direct substitute for film-backed tapes where high moisture resistance or extreme web tension is the controlling variable. On forms-weight paper, the selection of 3M 910 is justified when repulpability of broke is an operational requirement and when the splice is not exposed to water, steam, or excessive heat before the paper is converted. For indirect food-contact applications, documentation under 21 CFR 176.170 or 21 CFR 176.180 must be confirmed with the manufacturer; repulpability does not by itself establish regulatory clearance.