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Foam-assisted web forming and chemical application technologies have great potential to improve manufacturing efficiency and product quality in the paper and nonwovens industries. In this study, the benefits of foam forming and foam-assisted application of chemicals were demonstrated in a pilot machine trial. Uniform high-bulk webs of unrefined bleached softwood kraft pulp (BSKP) and viscose fibers were manufactured by foam forming. It was shown that foam formed low-grammage and high-bulk viscose fiber webs can be strengthened by foam-assisted application of latex onto the wet web. Correspondingly, foam-assisted application of carboxymethyl cellulose (CMC) and anionic polyacrylamide (A-PAM) improved the strength of the foam formed low-grammage and high-bulk BSKP web. Overall, the pilot machine results indicated that material cost savings could be achieved and a high-performance product could be manufactured with foam-based technologies.

Foam forming of cellulose fibre materials is based on an interaction between fibres and bubbles, which can take several material properties to new levels. To control the formed structure, the mechanisms of this interaction have been systematically investigated. This started with captive bubble studies where we analysed the interaction of a single bubble with various smooth cellulose and silica model surfaces. The bubbles adhered only to hydrophobic surfaces, and this attraction was sensitive to the surface tension. From this simplest case, the studied system gradually became more complex. We found that a bubble adheres weakly also to a submerged cellulose nanofibre (CNF) film, which could be explained by nanoscale surface roughness capturing nanobubbles. The interaction with real fibres was studied by pressing a single bubble against a fibre bed in water and sodium dodecyl sulphate (SDS) solution. Fibre type and surface tension had all apparent effects on the attachment. In the case of natural fibres, the presence of hydrophobic lignin clearly increased the fibre attachment on a bubble, while added SDS decreased the attachment with all fibre types. These findings agreed with the mechanisms found earlier using the model surfaces. Finally, when forming thick nonwoven materials using hydrophilic and hydrophobic viscose fibres, differences in fibre network structure and strength properties depended on the fibre hydrophobicity and surfactant type, as suggested by the results obtained in simpler systems.

Supplemental material, sj-docx-1-jef-10.1177_15589250221111507 for Spray and foam application of chemical binders to pulp fiber airlaids by Sara Paunonen, Tuomo Hjelt, Taina Kamppuri and Harri Kiiskinen in Journal of Engineered Fibers and Fabrics

Aqueous foam can be used as a transfer medium to form lightweight materials from natural and man-made fibers together with other types of raw materials. This review discusses mechanisms that underlie the forming process and thus influence physical properties of formed fiber networks such as microporous structure, strength behavior, and transport properties. Homogeneous fiber materials can be formed from versatile raw materials, which makes the technology suitable for a vast range of product applications. An intriguing feature of the method is that the wet foam characteristics provide an additional tool to tailor the performance of the dried material. Understanding foam rheology and how that is affected by added fibers is important in developing the forming process. We introduce both fundamental foam properties and practical forming methods, and show how the material properties are affected by the foam–fiber interaction. The basic features of an industrial production process are also described. The potential material properties are compared against key requirements in typical product applications.

Extensibility of paper web was investigated. Objective of the trial was to pilot production stages of highly extensible web. Bleached softwood kraft pulp (BSKP) from a Nordic mill was refined applying a high consistency (HC) phase at over 40% consistency followed by a low consistency (LC) refining at 4% consistency. Polymeric bi-component (BiCo) fibres with were used in the furnish. Water laid web forming at VTT SUORA pilot papermachine was successful. Pilot rolls were compacted (compressed) in-plane at a pilot machine. The VTT’s SutCo coating line was utilized for heat activation of the BiCo fibre containing rolls. Performance of the materials under different press-forming conditions was benchmarked using Packer 2020 pilot. Tray forming conditions had significant influence on performance of the materials. The in-plane compaction had the greatest influence on the elongation. The shrinkage that occurred by unrestrained drying was dependent of the pulp furnish.

We studied surface interactions in simplified fiber-foam systems with the captive bubble and fiber bed methods. The captive bubble technique was used to measure the bubble interaction with different cellulose model surfaces in sodium dodecyl sulfate (SDS) solution. The interaction of a single bubble with real fibers, submerged in SDS solution, was investigated using the fiber bed. Bubbles had clear adhesion to fiber surfaces in water, and the addition of SDS decreased this attraction. At high SDS concentration, the attraction was lost due to wetting transition. However, a smooth cellulose model surface did not attract bubbles even in the absence of surfactant. This suggests that the observed interaction with cellulose nanofibrils and fibers was caused by the presence of hydrophobic regions of the respective surface (e.g. lignin or nanobubbles).

Foam forming technology enables the production of versatile cellulose fiber materials extending from thick, porous and lightweight structures to stiff 3D forms, thin nonwovens and layered hybrid products. These renewable materials can find their use in many current industry sectors as an alternative for plastics, including packaging, high-efficiency air filters and substrates for biocatalytic conversion. Due to these wide application possibilities, controlling the final material properties is highly important. The stability and bubble size of the foam provide tools to tailor the density and pore size distribution of the formed fiber network [1]. Additional effects come from surfactant chemistry and fiber surface characteristics. Thus, it is necessary to understand the attachment of bubbles with distinct fiber types with varied surfaces and link that knowledge with foam architecture, stability and final microporous structure. To reveal the basic fundamental aspects related to the bubble-fiber interactions, a simple model surface approach was used. The air bubbles were contacted with either highly hydrophobic or highly hydrophilic silica surfaces as well as with amphiphilic cellulose model surfaces in the presence of sodium dodecyl sulfate (SDS) using the captive bubble method. Characterization of SDS adsorption on model surfaces was done using the quartz crystal microbalance. Generally, air bubbles had a repulsive interaction with hydrophilic silica surfaces and attractive one with hydrophobic surfaces. The role of various interaction components was analyzed in terms of calculated interface energy. For hydrophobic silica surfaces, we observed a transition from attraction to repulsion with increasing SDS concentration. The attachment tendency showed significant scatter near the transition due to metastable states of the system. Moreover, the critical SDS concentration was affected by electrolyte concentration. For the hygroscopic and amphiphilic cellulose model surface, the behavior was similar to the hydrophilic silica surface when using SDS as the surfactant. In applications like nonwovens with both natural and man-made fibers, the foam-formed structure is expected to be sensitive not only to the used fibers but also to the type and concentration of surfactant.

Foam forming technology enables the production of versatile cellulose fiber materials extending from thick, porous and lightweight structures to stiff 3Dforms, thin nonwovens and layered hybrid products. These renewable cellulosefiber-foam materials find their use in many current industry sectors and futurebionanomaterial architectures for e.g. packaging, high-efficiency air filters andsubstrates for biocatalytic conversion. The stability and bubble size of the foamprovide tools to tailor the density and pore size distribution of the formed fibernetwork. Additional effects come from surfactant chemistry and fiber surfacecharacteristics. Thus, it is important to understand the attachment of bubbles with these distinct fiber types and link that knowledge with foam architecture, stability and final microporous structure. We elaborate the fundamental aspects related to the bubble-fiber interactions using model surface approach. Air bubbles were contacted with either highly hydrophobic or highly hydrophilic silica surfaces as well as with amphiphilic cellulose model surfaces using captive bubble method. Characterization of surfactant adsorption on model surface was done using quartz crystal microbalance.Generally, air bubbles had a repulsive interaction with hydrophilic silica surfacesand attractive one with hydrophobic surfaces. The role of various interactioncomponents was analyzed in terms of calculated interface energy. For hydrophobic silica surfaces, we observed a transition from attraction to repulsion with increasing sodium dodecyl sulfate (SDS) concentration. The attachment tendency showed significant scatter near the transition due to metastable states of the system. Moreover, the critical SDS concentration was affected by electrolyte concentration. For the hygroscopic and amphiphilic cellulose model surface, the behavior was similar to the hydrophilic silica surface when using SDS as the surfactant. In applications like nonwovens with both natural and man-made fibers, the foam formed structure is expected to be sensitive not only to the used fibers but also to the type and concentration of surfactant.

The demand for environmentally friendly alternatives to oil-based materials in consumables is growing fast. Paper and board, made of natural wood fibres, provide a good starting point but the properties of fibre-based materials need be expanded to compete with plastics in different sectors. Foam forming technology provides several advantages compared to traditional water forming processes. Firstly, this next-generation manufacturing platform enables wider use of raw materials including e.g. very long fibres or particles of varied densities. Secondly, a broad range of different types of fibre-based materials can be formed, extending their end-use applications from packaging to textiles and construction materials.In order to produce foam-formed fibre materials with desired performance, one has to understand the interaction between wet foam and fibres. The stability and structure of the foam carrier medium provides a tool to tailor the material density and pore size distribution (A. M. Al-Qararah et al. “A unique microstructure of the fiber networks deposited from foam-fiber suspensions”, Colloids and Surfaces A: Physicochem. Eng. Aspects, 482, 544-553, 2015). However, structure and rheology of wet fibre foams do not depend only on the physical features, such as air content or bubble size distribution, but also on the surfactant chemistry and fibre surface properties such as smoothness and surface energy. Such features are still largely unexplored and their effects on the final material performance are not clear. We have approached this problem by using simple model systems with gradually increased complexity. The interaction between an air bubble and a model surface in varied surfactant solutions was studied for both cellulose and silica surfaces of different hydrophobicity. The adsorption of SDS surfactant on a surface was measured separately by quartz crystal microbalance. Air bubbles were found to have repulsive interactions with hydrophilic surfaces and attractive ones with hydrophobic surfaces. Surfactant concentration played a significant role in the transition from attraction to repulsion for semi-hydrophobic surfaces. These results are in line with earlier literature (D. Kosior et al. “Influence of non-ionic and ionic surfactants on kinetics of the bubble attachment to hydrophilic and hydrophobic solids”, Colloids Surf. A, 470, 333-341, 2015) and support the conception that hydrophobic interactions are necessary to explain the attractive forces between bubbles and fibres. The findings can be used to design new foam-formed structures and materials with desired performance.

Foam forming technology not only solves some long-standing issues related toflocculation in water forming but also enables widening of raw materials and enduse properties of fibre products. The technology can provide fibre materials with striking new features such as tailored microporous structures. Here the control of the foam properties and the interaction of air bubbles with fibres become important. We study these effects for aqueous foams using different types of surfactants and model fibre surfaces. The findings can be used to design new structures and materials that display low weight and high performance.

The invention relates to a method for the manufacture of thermoplastic fibrous materials comprising forming at least one foamed liquid comprising water and at least one foaming agent, forming a dispersion by dispersing fibers including long fibers in said at least one foamed liquid comprising water and at least one foaming agent, mixing the dispersion with a foamable liquid or dispersion comprising at least one thermoplastic polymer, forming at least one foamed dispersion, and conveying the foamed dispersion or dispersions to a foraminous support and draining liquid trough the foraminous support to form a web or a sheet, to obtain the thermoplastic fibrous material. The invention also relates to materials and products obtainable by the method, and uses related thereto.Patent family as of 23.11.2021CN107250458 A 20171013 CN201680007679 20160128 CN107250458 B 20191025 CN201680007679 20160128 EP3250751 A1 20171206 EP20160703166 20160128 FI127679 B 20181130 FI20150005062 20150129 FI20155062 A 20160730 FI20150005062 20150129 JP2018503756 T2 20180208 JP20170540067T 20160128 JP6636032 B2 20200129 JP20170540067T 20160128 KR20170109243 A 20170928 KR20177021404 20160128 US2017362775 AA 20171221 US20160547158 20160128 WO16120528 A1 20160804 WO2016FI50049 20160128Link to current patent family on right

The invention relates to growing medium structures comprising Sphagnum moss, to a foam-laid method for their manufacture and to the use thereof in horticulture, landscaping and forestry applications.Patent family as of 16.12.2021CA2925409 AA 20160324 CA20142925409 20140925 CA2925409 C 20211026 CA20142925409 20140925 EP3048872 A1 20160803 EP20140847890 20140925 EP3048872 A4 20170705 EP20140847890 20140925 FI125943 B 20160415 FI20130005965 20130926 FI20135965 A 20150327 FI20130005965 20130926 RU2016114407 A 20171031 RU20160114407 20140925 RU2016114407 A3 20180403 RU20160114407 20140925 RU2656551 C2 20180605 RU20160114407 20140925 US10701873 BB 20200707 US20140025120 20140925 US2016219810 AA 20160804 US20140025120 20140925 WO15044526 A1 20150402 WO2014FI50732 20140925Link to currentpatent family on right

A moldable fibrous product, includes foam-formed fibrous material selected from fibrous webs, paper webs, board webs, or sheets cut from any of the webs, at least one polymer selected from carbohydrate derivatives, polylactic acid, polyurethane and polyolefins impregnated in the web, and from 0.001 to 0.1 percent by weight of at least one foaming agent.Patent family as of 17.12.2021BR112015011734 A2 20170711 BR20151111734 20131122 EP2922904 A1 20150930 EP20130856205 20131122 EP2922904 A4 20160720 EP20130856205 20131122 FI125024 B 20150430 FI20120006227 20121122 FI20126227 A 20140523 FI20120006227 20121122 US2015284911 AA 20151008 US20130646744 20131122 WO14080084 A1 20140530 WO2013FI51097 20131122Link to current patent family on right

Foam coating is a promising method for applying a thin pigment layer of nanoparticles on a paper web. The interest in applying a low coat-weight coating layer arises from the need to create new functional surfaces using small amounts of new, typically expensive nanoparticles. The characterisation of thin pigment layer properties is more demanding than analysing traditional pigmented coatings layers because of the low coat weight (0.3-2.0 g/m2) and a corresponding low layer thickness of 1 µm or less. This characterisation requires surface sensitive measuring techniques and a combination of different microscopic and spectroscopic surface analyses. In this study, the pigment layer structure and chemical properties of nanosilica-coated paper were analysed. The results were utilised in the development of the foam coating process

Mass transfer in membrane supports is a challenge in forward osmosis (FO) membranes. A solution is a gradient structure with high 3D interconnected porosity constructed of fibrous elements. Porosity diameter should decrease from hundreds of microns to tens of nanometers in less than a half millimeter thickness. The foam forming method is used to construct multilayer carbon based support structures.

The invention relates to composite structures comprising peat moss, to a foam-laid method for their manufacture and to the use thereof.Patent family as of 15.10.2021CA2868935 AA 20140929 CA20132868935 20130327 CA2868935 C 20200324 CA20132868935 20130327 EP2831157 A1 20150204 EP20130769922 20130327 EP2831157 A4 20160413 EP20130769922 20130327 FI126092 B 20160630 FI20120005353 20120328 FI20125353 A 20130929 FI20120005353 20120328 WO13144449 A1 20131003 WO2013FI50342 20130327Link to current patent family on right

Dewatering is an essential step in the processing of fibrous materials. The smaller the material size, the more challenging the dewatering process becomes. The dewatering properties of materials containing microfibrillated cellulose (MFC) are known to be especially challenging, particularly at high MFC contents. This study shows that the foam-laid forming technique enables more effective dewatering compared to water-laid forming and enables structures with both high bulk and sufficient strength. In the study, papers were formed using special water-laid and foam-laid sheet formers and MFC dosage was varied up to 15%. Papers containing high amounts of MFC were found to be unsuitable for water-laid forming due to poor dewatering properties resulting from higher fine material, i.e. MFC, content. Foam forming provided good dewatering characteristics even at high MFC contents. In addition to dewatering properties, the mechanical properties of the papers were also studied. According to the strength results, the strength potential of MFC-containing foam-laid papers was found to be greater with respect to z-directional strength than in-plane strength.

Foam coating technique has shown to be a promising method for applying a thin pigment layer of nanoparticles on a paper web. The interest in applying a low coat weight coating layer is to create new functional surfaces using small amounts of new, typically expensive nanoparticles. The characterisation of thin pigment layer properties is more demanding than analysing traditional pigment coatings layers because of the low layer thickness of 1 µm or less with a coat weight of between 0.3 and 2 g/m2. This characterisation requires surface sensitive measuring techniques and a combination of different microscopic and spectroscopic surface analyses. In this study, the pigment layer structure and chemical properties of nanosilica-coated paper were analysed. The results were utilised in the development of the foam coating process

Fiber length is the fiber property which has been measurable for a long time. Therefore it is very often used as a measure of pulp properties. There are a vast number of experiments where changes in fiber processing have been reported as correlations between fiber length and paper properties of interests. This has caused some misunderstanding for the role of fiber length. Even though many process changes influence on fiber length, it usually is not the primal reason for the changes in paper properties. The effect of fiber length on paper strength has been studied extensively. The results, concerning for example the tensile index, vary a lot. Some results show that the tensile index of paper increases with fiber length and some studies show the opposite results. In most cases the discrepancies can be explained by the distinctive ways of fiber length manipulation. For example if the fibers are first cut and then refined, the results do not show the pure effect of fiber length. This is due to different behavior, and hence development, of short fiber pulps in relation to long fiber pulps during refining. In this paper we have made such experiments, that we can see the effect of fiber length as purely as possible and try to clarify the effect of fiber length alone to the strength properties. We produced fiber populations with narrow length distribution by a defined cutting procedure, thus keeping the other fiber properties like fiber width and fiber wall thickness almost unchanged. Highly oriented long fiber fraction sheets were prepared using a dynamic sheet former. Dried sheets were cut in cross direction with a paper cutter applying cutting intervals of 0, 1, 2 and 5 mm. After cutting, the paper strips were hot disintegrated. Laboratory sheets were prepared from these disintegrated pulps. The modulus of elasticity is independent of fiber length whereas the tensile index increases with it. The difference between these strength properties is that the tensile index contains also the effect of inelastic changes in paper during the testing. Thus it turns out that also stretch of paper depends on fiber length. The elastic properties of the paper are governed at the length scale of the distance between the nearest bonds along the fiber, i.e. at the length of fiber segments. The factors affecting elastic properties of paper are the orientation and elastic modulus of the fiber segments. Inelastic changes is paper occur due to breakage of fibers or bonds. In such case the fiber length plays a role, because longer fibers enforce weak areas better than shorter ones. For that reason the tear strength is strongly dependent on fiber length, as is well known.

Although fiber length is one of the most often measured property of paper raw materials, the pure effect of it on paper properties is not usually clear. The reason for that is the difficulty to vary only the fiber length while other properties such as fiber width are kept unchanged. To get a more accurate understanding of the significance of fiber length, fractions with different narrow-distributed fiber lengths were produced in the laboratory from the same original pulp by using a defined cutting procedure, which enables to change only the length dimension of fibers but keeping other properties such as fiber width rather unchanged. Commercial pulps - bleached kraft pine pulp, and spruce CTMP - were used as fiber material. The fiber dimensions and related properties of the resulting fiber material were determined with kajaani FiberLabT. Handsheets were produced following a certain procedure and subsequently treated in a laboratory calender to investigate the effect of fiber length especially on surface and strength properties. As results, the development of surface roughness, gloss, apparent density and strength properties (tensile and tear) with a narrow fiber length distributions are presented. A surprising conclusions for the significance of fiber length and its distribution for paper property development is that the fiber length distribution has obviously no significant effect on the strength development if the cross-sectional dimensions of the fibers remain rather unchanged, and that the use of average values is sufficient to describe property developments of paper.