VINNAPAS 5518 H

In tufted carpet precoat production, the high-viscosity VAE dispersion VINNAPAS 5518 H is compounded with ground calcium carbonate (GCC) slurries at filler-to-dispersion ratios between 200 phr and 450 phr. The primary processing conflict is not film formation but shear-stable filler acceptance under continuous blade-over-roll coating at line speeds from 15 m/min to 35 m/min. Because the dispersion exhibits a Brookfield viscosity in the range of 12,000 mPa·s to 20,000 mPa·s at 20°C, transfer into existing PVAc precoat lines requires dilution with 5 wt% to 12 wt% water to bring application viscosity to 3,000 mPa·s to 8,000 mPa·s measured on a spindle 4/20 RPM configuration. Addition of an anionic polyacrylate dispersant at 0.05 wt% to 0.20 wt% based on dry filler prevents calcium carbonate agglomeration; nonionic ethoxylated wetting agents are held below 0.3 wt% because foam generation in the holding tank changes the blade gap at the lick roll. The compound is metered through a pug mill or continuous auger mixer, passes through a de-aeration chamber, and is applied by a blade-over-roll coater at a gap between 0.5 mm and 1.5 mm. Precoat weight is controlled between 250 g/m² and 600 g/m² dry add-on depending on the tuft bind specification.

The wet precoat enters a three-zone gas-fired oven with zone settings at 120°C, 145°C, and 155°C. The surface temperature of the compound must remain below 160°C; residence time at the peak zone is a narrow ±5°C processing window because VAE films embrittle above 160°C and remain water-sensitive below 135°C. This window is monitored by continuous infrared pyrometry at the interface between the precoat and the secondary backing. Tuft bind performance is evaluated per ASTM D1335; values above 24 N per tuft are typically required for heavy-traffic broadloom, while carpet tile producers often set internal limits above 18 N per tuft. The finished backing also must pass ISO 6356 for electrostatic propensity when nylon face fibre is used. The dispersion is not freeze-thaw stable: storage below 5°C produces irreversible sediment, and containers must be kept above 5°C and below 35°C. Boric acid-based flame retardant additives are avoided because polyvinyl alcohol colloid complexation produces coagulum at pH above 8; sudden pH shifts above 8 cause viscosity drift within 24 hours.

Woodworking Adhesive Formulation Limits Under DIN EN 204 D3 Load Profiles

For cold-press wood assembly, VINNAPAS 5518 H is blended with a PVAc homopolymer dispersion and calcium carbonate filler in a standard weight-ratio band: 40 wt% to 70 wt% VAE dispersion, 20 wt% to 40 wt% PVAc homopolymer, 5 wt% to 15 wt% filler, and 0.5 wt% to 1.5 wt% plasticizer. The VAE lowers the minimum film-forming temperature and contributes plasticiser-free adhesion to high-density hardwood edges, but total VAE above 70 wt% of polymer solids extends open assembly time beyond 15 minutes and reduces final Shore D hardness by 4 points to 8 points. The blend is mixed in a planetary paddle mixer at 25 rpm to 50 rpm for 20 minutes; filler is added incrementally to avoid agglomerates larger than 100 µm. Application is by transfer roller or curtain coater, targeting 80 g/m² to 200 g/m² wet film thickness on both faces. Pressing is performed in a hydraulic cold press at 0.7 MPa to 1.0 MPa for 15 minutes to 60 minutes depending on wood species and moisture content. Where water-resistant class D3 under DIN EN 204/205 is required, the adhesive is tested after 4 days cold water immersion; shear strength must remain above 2 N/mm² on beech test pieces. For D4 service, an aliphatic polyisocyanate hardener is added at 3 wt% to 5 wt% immediately before application; the pot life then narrows to 45 minutes to 90 minutes. End products include edge-banded kitchen components, window frame corner joints, and stair tread lamination.

When relative humidity exceeds 60%, partial pre-drying with forced air at 30°C to 40°C for 2 minutes to 5 minutes is required to remove surface water before panel assembly. Failure to pre-dry at high RH produces translucent glue lines and reduces shear strength by 10% to 15% because water plasticises the PVAc-rich phase. Ammonia-based pH adjusters are not used in this blend because the resulting rapid pH swing above 6.5 destabilises the VAE colloid and produces seed-like coagulum in transfer lines. The product is registered under REACH; emission testing for interior furniture adhesives may be carried out per ISO 16000-6 with a chamber loading factor of 1.0 m²/m³.

Paper-to-paper lamination lines that convert folding cartons at machine speeds above 150 m/min require a wet tack window of 3 seconds to 8 seconds and dry bond strength sufficient to cause fibre tear. VINNAPAS 5518 H is formulated with polyvinyl alcohol at 5 parts to 15 parts per 100 parts dispersion as a co-film former, carboxymethyl cellulose at 0.1 parts to 0.3 parts as a rheology modifier, and a mineral-oil-free defoamer at 0.05 parts to 0.15 parts. The application viscosity is adjusted to 1,500 mPa·s to 3,500 mPa·s at 20°C for gravure or wire-wound rod application. Coating weight is maintained between 3 g/m² and 12 g/m² dry. Nip pressure on the laminator is set at 0.4 MPa to 0.8 MPa. Drying is performed in a tunnel at 70°C to 100°C for 10 seconds to 20 seconds. Blocking resistance of the finished blank is evaluated in a stack at 40°C and 60% relative humidity for 72 hours; film-to-film blocking is considered unacceptable if peel force exceeds 0.5 N/25 mm on a universal tensile machine.

For food packaging, adhesives containing the dispersion can be formulated to comply with FDA 21 CFR 175.105 as an indirect food additive for the adhesive component, provided all co-formulants are also listed or cleared. European paper and board compliance may reference BfR Recommendation XIV for paper and board contact; migration testing per EN 1186-1 is carried out by the converter when the laminate is intended for fatty food contact. The dispersion is not positioned for direct food contact without a functional barrier because it is not formulated to meet FDA 21 CFR 176.170 surface contact conditions. End products include bakery carton blanks, frozen food sleeves, envelope window lamination, and medical device carton inner wraps where fibre tear bond is specified.

Does High Viscosity Restrict Spray-Head Performance in Nonwoven Binder Application?

The high Brookfield viscosity of VINNAPAS 5518 H makes neat spray application impractical in airlaid nonwoven lines. Direct spraying through hydraulic nozzles produces filament breakage and uneven add-on unless the dispersion is diluted to between 5% and 15% solids. Dilution with deionized water is carried out under low-shear agitation below 100 rpm to avoid air entrainment; a filter of 100 µm mesh is installed upstream of the spray bar. Spray nozzle clogging is the dominant failure mode when unfiltered dilution is used; batch-to-batch viscosity differences of ±2,000 mPa·s at the concentrate stage require in-line viscosity correction before the spray manifold. Field data from airlaid lines indicate that nozzle blockages increase sharply when the diluted dispersion is held in the day tank longer than 6 hours without gentle recirculation, because evaporation at the liquid surface forms a high-solids skin that dislodges into the supply stream.

Foam application is the preferred alternative for full-strength use. An Oakes-type foamer with blow ratios between 4:1 and 12:1 produces stable fine-cell foam that deposits binder at 12 wt% to 18 wt% add-on on airlaid cellulose. Foam half-life under shear must exceed 120 seconds for uniform deposition. Curing in a belt oven at 130°C to 150°C for 30 seconds to 180 seconds develops wet strength; tensile strength is tested per ISO 9073-3, and wet tensile retention above 80% of dry strength is commonly specified for wipes and tabletop products. The presence of coarse particle size near 1.0 µm reduces binder migration compared with fine-particle VAE grades, which is advantageous for airlaid core integrity but narrows the maximum permissible line speed because film formation at the fibre intersections is slower. End products include airlaid hand wipes, feminine hygiene acquisition layers, industrial wiping substrates, and packaging void fill produced by airlaid technology. Compliance for hygiene applications may reference Oeko-Tex Standard 100 Product Class I; REACH registration is maintained for the European market.

When High-Viscosity VAE Replaces PVAc Homopolymer in Flooring Adhesive Systems

When VINNAPAS 5518 H replaces PVAc homopolymer in flooring adhesive systems, the main change is not application viscosity but plasticiser-free adhesion to PVC wear layers and polyurethane foam backings. Formulations typically contain 50 wt% to 80 wt% VAE dispersion as polymer solids, 5 parts to 15 parts of a benzoate or citrate plasticizer per 100 parts dispersion, 20 parts to 60 parts calcium carbonate filler per 100 parts dispersion, and an associative polyurethane thickener at 0.1 wt% to 0.5 wt%. The final trowel viscosity is targeted between 40,000 mPa·s and 80,000 mPa·s at low shear. Open time is tested per EN 1372; values from 20 minutes to 45 minutes at 23°C and 50% relative humidity are typical. Wet-set adhesion to vinyl composition tile and luxury vinyl tile is evaluated by peel per ISO 11339; failure must occur in the adhesive layer with no interfacial delamination from the substrate. Creep resistance under a sustained static load is tested per EN 1902 on a 1 kg weight for 24 hours; displacement below 0.1 mm is the internal set point for rigid PVC plank adhesives.

Processing on a notched trowel line requires a notch depth of 1.6 mm to 3.2 mm depending on substrate irregularity. On absorbent concrete, priming with a diluted dispersion at 1:1 water ratio at 50 g/m² to 100 g/m² prevents pinhole formation. The adhesive must not be applied below 10°C or above 30°C; temperature outside this range changes open time unpredictably and can cause premature skinning in the trowel ridges. Facility audits of flooring lines show that high-viscosity VAE formulations are more sensitive to substrate moisture than PVAc homopolymer adhesives; concrete moisture emission above 3.0 kg/m² per 24 hours measured by a calcium chloride kit delays final strength development by 12 hours to 24 hours. The dispersion must be protected from frost because freeze-thaw cycling causes irreversible grit formation that cannot be redispersed by high-shear mixing. End products include luxury vinyl tile, linoleum, rubber tile, and cork underlayment adhesives. Classification may be made under EN 14293 for flooring adhesive systems.

Flock coating operations processing cotton-polyester base fabric for automotive interior trim require a controlled rheology profile and a cure response that avoids colour shift in the adhesive film. VINNAPAS 5518 H is compounded with a blocked aliphatic polyisocyanate crosslinker at 0.5 wt% to 2.0 wt% based on dry polymer, an organic acid catalyst at 0.1 wt%, and a silicone-free deaerator. The mixture is applied by engraved roller at wet film weights from 80 g/m² to 200 g/m². Flock fibres are then applied electrostatically; the viscosity of the adhesive film must remain above 20,000 mPa·s at low shear to hold flock fibres vertical during electrostatic deposition. Curing is performed in a stenter frame at 140°C to 160°C for 2 minutes to 5 minutes. Wash resistance is tested per ISO 6330 programme 4N and abrasion per ISO 12947-2; mass loss below 2% after 5,000 cycles is typically specified. End products include flocked glove box liners, seat side facings, trunk trim, and decorative wallcovering with mechanical embossing.

Published data for this specific VAE grade in automotive flocking is limited; converter trials generally rely on the same chemistry class for non-halogenated interior components. The dispersion is not recommended for exterior textile lamination because water resistance under ISO 6330 does not match crosslinked acrylic systems without additional surface treatment or topcoat. Emissions testing for interior parts may be performed per VDA 278 with a total VOC limit of 100 µg/g toluene equivalent and a FOG limit of 250 µg/g hexadecane equivalent as common line specifications.

Perfect binding lines processing high-page-count catalogues and softcover books require a low-foaming primer and side glue with short setting time and high page pull strength. VINNAPAS 5518 H is diluted with water to 30% to 40% solids and thickened with 0.2 parts to 0.5 parts of fumed silica per 100 parts of diluted dispersion. The adhesive is applied at 50 g/m² to 150 g/m² on the spine via a roller applicator, then the block is nipped at 0.4 MPa to 0.7 MPa. Setting time on absorbent uncoated paper is 3 seconds to 10 seconds at 23°C; page pull is evaluated on a universal tensile machine with jaw separation at 100 mm/min. Coated spine stock above 150 g/m² shows reduced adhesion because ink and coating binders compete for surface porosity; a co-solvent primer is required on those substrates before application of the water-based dispersion. End products include softcover books, catalogues, magazines, and self-cover manuals. The formulation is not suitable for one-shot polyurethane replacement in high-temperature storage above 50°C because creep deformation under sustained book weight can exceed 0.5 mm after 72 hours at 50°C.