Fibra de filamento Kuraray KURALON 55O1-PVA

Slurry dewatering behaviour on a Hatschek machine shifts when KURALON 55O1-PVA filament fiber is introduced as a partial replacement for refined cellulose pulp in non-asbestos fiber-cement sheet formulations. The filament is typically cut to 6 mm or 12 mm and dosed at 0.8–2.2 vol% of total furnish solids. Bagged filament should be stored below 65% RH before batching; moisture regain above 5 wt% alters the dry solids proportion in the furnish. Inline rotary cutting and forced-air feeding reduce filament entanglement during hydro-pulper dispersion; the PVA filament enters the mixing chest after pulp refining has reached 30–45 °SR Schopper-Riegler freeness. Because the PVA filament does not fibrillate like refined pulp, the furnish drainage rate changes relative to an all-cellulose reference stock. On production-scale Hatschek lines, vacuum box retention must be increased by 10–20% when the PVA dosage reaches 2.0 vol% to maintain a single-layer sheet thickness of 0.9–1.1 mm before stacking. The green sheet is transferred from the felt to a forming roll, cut to panel dimensions, and autoclaved at 170–180 °C under saturated steam for 8–12 h when silica sand and cementitious binders are used. Compliance for the finished board is evaluated against EN 12467:2012+A2:2018 and ISO 8336:2017, with flexural strength, impact resistance, and dimensional stability classified according to the specified NT category. The terminal output comprises ventilated façade panels, soffit boards, and corrugated roofing profiles. Operating boundary data indicate that PVA dosage above 2.5 vol% can reduce green sheet cohesion and increase lamination defects at the forming roll, because unbound water trapped between non-fibrillated filaments impedes interlayer bonding.

What Restricts PVA Filament Dosage in Cast ECC Mixes?

In cast engineered cementitious composites, KURALON 55O1-PVA filament fiber is normally added at 2.0 vol% of the total mortar volume, corresponding to approximately 26 kg/m³ for a filament density of 1.30 g/cm³. The mix design typically pairs the fiber with Type I Portland cement, Class F fly ash at a 1.2–1.4 fly ash-to-cement mass ratio, silica sand with maximum aggregate size 0.3 mm, and polycarboxylate ether superplasticizer at 0.4–0.8 wt% of cementitious mass. The primary dosage restriction is interfacial bond saturation: uncoated PVA filament forms strong chemical adhesion to cement hydrates, so crack openings below 250 µm can trigger fiber rupture before pullout, shifting the composite from multiple micro-cracking toward localized fracture. To extend strain capacity, the filament may be specified with a controlled surface oiling agent, or the matrix may be adjusted with additional supplementary cementitious material to reduce interfacial toughness. Batching is performed in a high-shear planetary mixer; dry ingredients are blended for 2 min, water and superplasticizer are added, and the filament is introduced into the wet mortar at slow speed for 2–3 min to avoid clumping. Specimens cured at 20 °C and 95% RH are tested under ASTM C1609/C1609M four-point flexural loading. Fiber-reinforced concrete specification compliance is referenced to ASTM C1116/C1116M Type III synthetic fiber reinforcement. Terminal components include seismic coupling beams, bridge deck link slabs, and patch repair overlays with maximum aggregate size below 1 mm.

Wet strength retention of braided KURALON 55O1-PVA filament lines under continuous seawater immersion is the primary selection criterion for aquaculture cage netting and longline rope applications. The filament is processed into three-strand twisted or eight-strand braided ropes with rope diameters from 6 mm to 24 mm, depending on cage collar tension and current loading. Unlike polyethylene or polyamide, the high-tenacity PVA filament does not soften at standard seawater temperatures and retains 80–90% of its dry tensile breaking load when wet; specific retention values depend on rope construction and the filament saponification degree. Heat-setting at 120–140 °C is applied to control filament shrinkage during service. Compliance testing for the finished rope follows ISO 2307:2019 for breaking load and elongation at break, with wet conditioning and cyclic loading protocols developed by rope producers for marine certification bodies. Terminal products include aquaculture cage netting lacing, mussel longline ropes, and short-run mooring hawsers where low elongation and high abrasion resistance are required. The operational boundary is defined by continuous service in seawater above 35 °C under sustained cyclic loading; published data for this specific configuration is limited, and accelerated aging trials should be conducted before deployment in high-current tropical sites.

When PVA Filament Replaces Steel Fibres in Tunnel Shotcrete

When KURALON 55O1-PVA filament is dosed at 0.5–1.0 vol% in wet-mix shotcrete for temporary tunnel linings, the main process change is the elimination of steel fibre balling at the nozzle and a measurable reduction in rebound. The filament is cut to 12 mm or 18 mm before entering the agitator truck; the dry premix contains cement, aggregates up to 8 mm, silica fume at 4–8 wt% of cementitious mass, and high-range water reducer. At the nozzle, compressed air at 4–6 bar projects the mix onto the substrate, and the PVA filament tends to orient parallel to the surface, improving early-age crack control. The target slump before transport is 180–220 mm to maintain filament dispersion without segregation. Sprayed concrete specification is verified under EN 14487-1:2022, and the fiber reinforcement contribution is assessed through energy absorption panels and residual strength classes referenced in the relevant European or national sprayed concrete provisions. The terminal application includes transition zones between drill-and-blast headings and cast-in-place concrete liners, plus temporary slope stabilization shells. The operational limit is the maximum dosage of 1.0 vol%; above this level, pump pressure increases measurably and nozzle pulsation creates surface roughness and rebound variation on production-scale tunnel units.

Alkali-Resistant Textile Scrim Reinforcement for Plaster Façade Systems

KURALON 55O1-PVA filament can be converted into woven or Raschel-knitted scrim fabrics for external thermal insulation composite systems and render carrier meshes. The scrim is produced with mesh openings of 6 mm × 6 mm to 10 mm × 10 mm and filament counts from 200 dtex to 600 dtex. Because the PVA filament retains tensile strength in the alkaline environment of cementitious base coats at pH 12–13, the scrim does not require the latex or epoxy coating commonly used on glass-fibre meshes for alkali protection. The scrim is embedded into a 3–5 mm cementitious base coat at a coverage rate of 1.2–1.5 kg/m²; pull-out and interface shear resistance are governed by mesh aperture and embedment depth. Mechanical performance is evaluated under ETAG 004:2013 procedures for EIFS base coat reinforcement, including alkali ageing followed by tensile strength retention testing. Terminal finished products include exterior façade reinforcement mesh, plaster carrier fabric, and corner reinforcement strips for window reveals. The processing boundary is the minimum embedment depth: scrim placed only on the surface or embedded below 3 mm exhibits reduced pull-out capacity and should not be used for structural crack bridging.

On high-speed bag-closing lines, KURALON 55O1-PVA filament is configured as a two-ply or three-ply sewing thread for cement sacks, mineral-filled bags, and chemical filter bag closures. The thread is produced from 200 dtex to 1000 dtex filament yarns with ply twist in the range 400–800 tpm, depending on needle size and seam strength requirements. The process sequence comprises precision winding, two-for-one twisting, heat-setting at 110–130 °C, and lubricant application to reduce needle friction. On production-scale bag-closing machines operating at 10–25 m/min, the PVA sewing thread maintains loop strength during high-speed needle insertion, while resisting the alkaline dust environment typical of cement bagging lines. Thread tensile testing follows ISO 2062:2009 for breaking force and elongation from packages; seam classification is defined under ISO 4915 for stitch type and seam configuration. Terminal finished products include cemented sack closures, mineral filler bag seams, and process filter bag assembly. The operational boundary is acid exposure: continuous contact with strong mineral acids at pH < 2 reduces the thread tensile strength, and acid-filled bag closures should be secured with alternative filament types.