3M 8507 Repulpable Forms-Splicing Tape is a single-faced, tan paper carrier coated with a rubber-based pressure-sensitive adhesive. The structure is manufactured for butt splicing of continuous business forms, carbonless multi-part sets, tabulating card stock, and bond paper webs on printing, collating, and forms-processing lines. The paper carrier disperses in standard alkaline or neutral paper repulping conditions, while the adhesive is formulated to fragment into screenable particulates rather than remain as a continuous film. Typical physical properties include total thickness 4.5 mil (0.11 mm), peel adhesion to stainless steel 40 oz/in (11 N/100 mm) under ASTM D3330, tensile strength at break 32 lb/in (560 N/100 mm) and elongation at break 3.0% under ASTM D3759. Standard roll widths include 0.75 in (19 mm), 1.0 in (25 mm), 1.5 in (38 mm), and 2.0 in (51 mm), with a standard length of 60 yd (55 m) and a common core diameter of 3 in (76 mm).

The principal distinction between 3M 8507 and general-purpose film splicing tapes is repulpability. A polyester or polypropylene splicing tape remains as a continuous polymer film in the pulper unless manually removed. That film can pass through broke screening and contaminate sheet formation. In contrast, a repulpable paper tape is designed to remain with the spliced broke. Under typical pulper conditions at 4%–6% consistency and stock temperatures from 35°C to 55°C, the paper carrier separates into fiber within 5 min to 15 min under medium shear. The rubber adhesive does not dissolve; it coalesces into rubber crumbs that are removed by pressure screens or centrifugal cleaners. Mill acceptance is generally based on absence of tacky deposits on handsheets and no accumulation on press rolls or dryer fabrics. Published data for this specific product in acidic sulfite pulping at pH below 5.0 is limited, and qualification under those conditions requires mill-specific trials.

Adhesion on carbonless forms paper is influenced by microcapsule coating chemistry and coat weight. The product is not generally recommended for poly-coated or resin-impregnated papers because the rubber adhesive can lose shear holding force on plasticized coatings. On standard bond paper, peel values after 20 min dwell are commonly higher than immediate peel values; after 24 h at 23°C, peel adhesion can increase by 10% to 30% above the initial value. This aging behavior is inherent to rubber-resin adhesives and must be considered when collated form sets are stored before imprinting. At temperatures below 32°F (0°C), tack is substantially reduced. Splicing should be performed at temperatures above 50°F (10°C) unless line-side trials prove otherwise. In high relative humidity above 60%, the paper carrier can absorb moisture, increasing caliper and decreasing tensile stiffness; sealed packaging should be opened only at point of use.

What Limits Splice Integrity on High-Speed Continuous Forms Collators?

On a continuous forms collator running at 250 m/min to 400 m/min, the splice must carry web tension without creep, maintain pin-feed hole alignment, and avoid caliper buildup. The dominant failure mode is not instantaneous tensile break but slow peel propagation from the splice edge when the adhesive has not fully wet-out the paper surface. Rubber-based adhesives reach contact clarity on uncoated bond within the short nip dwell of a collator splice head, typically less than 0.5 s. The tape has low elongation of 3.0%, so it resists registration drift but does not absorb misalignment. The splice head must butt the two webs without gap or overlap. A butt splice with a gap greater than 0.2 mm can cause pin-feed tracking error, while overlap greater than 0.1 mm can create a stack height difference at folding stations.

On a collator with a pin-band feed system, a butt splice can fail at the pin-feed holes if the punched holes in the splice area are stretched or not aligned. The tape thickness of 4.5 mil (0.11 mm) is greater than the 3.5 mil (0.089 mm) to 4.0 mil (0.10 mm) caliper of typical 20 lb bond paper. This increase is within the tolerance of most collator folding and stacking mechanisms but can accumulate if multiple splices occur in a single stack. In burst-mail processing lines, folded stack height tolerance is often ±2 mm per 500 forms. Repeated splices contribute to stack height variation. Line operators should limit splice count per pack to the minimum required and position splices outside the primary fold zone where possible.

Surface preparation is limited to removal of dust, paper dust, and loose fibers from the reel ends. The tape should be applied at a minimum pressure of 2 bar (29 psi) with a hand roller or splice head to seat the adhesive. Because the adhesive is pressure-sensitive, dwell under pressure affects final peel. On manual splices, a hand burnisher improves wet-out on rough bond paper. For edges, a small overlap of 3 mm to 5 mm is sometimes used to prevent edge lifting. The product is a permanent splice tape for forms manufacturing, not a removable hold tab. It is not recommended for tab positioning where repeated peel-away is required.

Repulpability Verification Methods and Alkaline Broke Handling

The product is tested under TAPPI UM 213 laboratory repulpability screening. The method involves defibering a known mass of tape in a laboratory pulper, screening the stock through a slotted screen plate, and examining the screen rejects for film or adhesive residue. A repulpable tape should not form a continuous film that would blind the screen plate or adhere to handsheet surfaces. Under standard alkaline pulping at pH 8.0–10.5, the paper backing of 3M 8507 hydrates and separates into fibers, while the rubber adhesive fractures into fragments that can be removed by 0.15 mm slotted screens. The product is supplied without silicone release coating on the paper backing, which reduces the risk of silicone deposits on paper machine clothing. Unlike film tapes, the product does not require manual removal before broke handling and does not generate plastic film tails that wrap around pulper rotors.

In alkaline papermaking, stickies from rubber adhesives can be destabilized by pH and calcium carbonate. The rubber adhesive in 3M 8507 is formulated to agglomerate rather than disperse into colloidal stickies. Screen rejects consist primarily of adhesive crumbs, not fiber bundles. If the pulper uses a ragger or rope, the product may also be caught by the ragger, but that is not the primary removal mechanism. Mills that use 0.10 mm or finer slotted screens generally report fewer visible stickies in the final sheet. For mills running neutral pH grades, repulpability behavior is similar. For closed-loop deinking systems with flotation stages, published data for this specific product is limited, and mills should conduct a laboratory repulpability test on the exact broke blend before permitting the splice material into recovered broke.

Compared with a polyester film splicing tape of the same total thickness, 3M 8507 exhibits lower tensile strength and lower temperature resistance. A polyester carrier typically has higher tensile strength, but the film tape is not repulpable; its carrier remains intact in the pulper and must be removed by screening or manual extraction. A paper tape is mechanically weaker but more compatible with paper broke. Compared with an acrylic transfer adhesive film, the rubber adhesive on 3M 8507 generally shows faster tack development on rough paper surfaces at room temperature, but lower resistance to high temperature and UV exposure. This trade-off defines its use in forms splicing rather than industrial assembly or exterior applications. The product is not designed for extended outdoor exposure, continuous immersion, or contact with low-surface-energy polymer webs.

When Reel Changes Are Made at Full Line Speed on Web Presses

In flying splice operations, the tape must maintain fiber-tearing peel on paper surfaces during reel acceleration. The rubber adhesive shows high tack to paper fibers within 0.5 s of application, but final adhesion continues to build for several minutes. On high-speed commercial web presses, splice failure occurs if the new roll is brought to line speed before adhesive dwell has reached a stable plateau. Minimum dwell after splice is often set at 30 s to 90 s before full acceleration. A butt splice made with 3M 8507 carries the same web tensile challenge as a film splicing tape; however, the paper carrier itself can tear under shock loading. With tensile strength of 32 lb/in (560 N/100 mm), a 1.0 in wide splice tape has a theoretical breaking force of 32 lb (142 N). The tensile load in a web of 20 lb bond at 0.4 lb/in (70 N/100 mm) tension is below this value, but shock from reel out-of-roundness can generate transient loads twice steady-state. Splice survival therefore depends on reducing reel runout and maintaining edge alignment rather than using increasingly thicker tape.

In high-speed web offset applications, the splice area passes through printing blankets. The rubber adhesive can exude slightly at dryer or fuser temperatures above 180°F (82°C); if the press has hot dryers exceeding this value, use of a film splice tape with a silicone adhesive should be considered instead, with manual removal of splice material before broke repulping. For laser forms printing lines, the splice passes through fuser rolls that may exceed the maximum continuous service temperature if the line uses high-speed hot-roll fusing. If the tape contacts transport belts or rollers above the service limit, softened adhesive can transfer. The product is not recommended for splicing polyester film, silicone-coated label liners, or low-surface-energy polymer webs. Standard web widths and roll lengths listed above are based on current manufacturer product data; alternative formats must be verified against current manufacturer documentation.

The product is not validated for direct food contact, medical packaging, or aerospace applications. In high-volume forms manufacturing, its function is limited to repulpable splicing of paper-based continuous forms where the splice can remain in recovered broke without generating non-dispersible film contamination. Proper use requires verification of repulpability under the specific mill pulping conditions, adhesion testing on the specific paper grade, and control of splice placement to avoid multiple splices in a single folded stack.