DE69936684T2 - A method for improving and regulating the adhesion between cellulosic fibers or a cellulose-synthetic fiber blend in a process for producing nonwoven products - Google Patents

Abstract

The new method combination is aimed at improving and regulating the adhesion between similar or different fibers in connection with a method for producing hydroentangled and thermobonded fabrics from cellulose and synthetic fiber blends. Improvement of the fiber adhesion aims at providing highstrength and well absorbing, stable, non-linting nonwoven structures containing high cellulose concentrations. In the new method, adhesion strength is improved by increasing kinetically and quantitatively the contact and wetting between molten polyolefin used for cellulose bonding, and the cellulose, and providing in the cooling contact site transcrystallization following heterogenous nucleation of the polyolefin structure. In order to provide for pre-contacts between the cellulose and cellulose-polyolefin fibers, effectivated hydrogen bonding between the cellulose fibers is used, especially when mechanically hydroentangling cellulose using unreacting synthetic fiber (polyamide, ester). In order to improve adhesion strength, the surface structure of the polyolefin and/or cellulose fibers has to be modified. The surface structure of the polyolefins is modified by molecular chain degradation caused by spinning oxidation, in order to decrease the surface energy, viscosity and temperature of the surface melt formed in bonding. The modification of the cellulose surfaces takes place by heat treatment in a polar liquid, whereby in connection with a conversion of the cellulose crystal structure (C-II (C-I) -> C-IV), its surface energy, crystallinity degree and crystal lamellar thickness of its superstructure increase. Hydrogen bond formation is activated with a combined corona and steam wetting-pressure-drying method.

Description

The new procedure is to improve and regulate liability between the same or different fibers in conjunction with a Process for the preparation of hydroentangled and thermal bonded tissues of cellulose or cellulose-synthetic fiber blends directed.

at The process will be both natural as well as regenerated cellulose fibers and primarily polyolefin and polyester synthetic fibers used.

regenerated Cellulose fibers can even before the thermal bond or hydroentanglement process be mixed with synthetic fibers. A fibrous layer that is short Pulp cellulose fibers as such or as a premix with a Polyolefin microfiber is produced, with a synthetic fiber support under Use of conventional Method hydroentangled, wherein it is aimed in the With regard to the cellulose either a laminate or so good as possible To obtain degree of mixing. By the adhesion between the Fibers in a nonwoven product is improved, it aims at it off, except high absorbency and high absorbency a stable and non linting structure of the product with a to provide high cellulose content.

Textile Materials for close medical applications Fibers, monofilaments and multifilament yarns, woven and nonwoven products and composites. The main requirements of medical textiles are dependent from the intended application absorbency, strength, flexibility, softness, sometimes biological stability or biodegradability. Cotton, pulp and silk fibers are the most common natural Materials in medical textiles. These are being distributed in combination with regenerated cellulose fibers (inter alia rayon viscose) in surgical, non-implantable materials and in articles for medical Supply and hygiene used. Of the synthetic materials are primarily polyesters, polyamides and polyolefins in medical Textiles used.

The New method of regulation is primarily concerned with both surgical Textiles as well as textiles for medical care and hygiene. The former group includes u. a. Wound dressing textiles, gauzes, adhesive plaster and the the latter textiles for Surgical clothing, blankets, incontinence diapers, protective clothing, Cleanroom Wipes etc.

medical Nonwoven textiles are primarily made using two various types of processes, namely thermal bonding and hydroentanglement process. The use of binding Polymers or corresponding binders in liquid form are used in medical textiles primarily for reasons hygiene and also the properties of the product. Liquid, short-chain Binders cover and encapsulate in particular absorbent fibers and also prevent the production of semipermeable, absorbent Textiles (textiles for Surgical gowns).

Fine cellulosic lint, which are detached from the structure of the non-woven fabric as a result of the manufacturing technique, are very harmful. Linting is a consequence of, among other things, the short length of both natural and synthetic fibers, microfibrillation and other factors. The requirements for air purity in hospital operating rooms and some special departments place very limited limits on particle emissions from medical textiles. The US Federal Standard 209E, 1992, defines that the air in a clean room of purity class 100 contains at most 100 particles with a diameter d ≥ 0.5 μm per cubic foot, ie 3531 per m ³ . It is very difficult to achieve this value with, for example, pulp fiber containing hydroentangled webs (50% by weight cellulose, weight 70 g / m ² ) when tested by conventional test methods. In addition, a hydroentangled fabric is very unstable, regardless of changes in the manufacturing processes, in terms of detachment of cellulose fuzz due to the shortness of the pulp cellulose fibers and their broad length distribution, and is also particularly susceptible to bending and shear.

The Features of the invention are disclosed in the appended claims.

The object of the invention is therefore a method for improving and regulating the adhesion between cellulose fibers or cellulose-synthetic fiber mixtures, in particular polyolefin fiber mixtures, wherein water jet bonding and / or thermal bonding methods are used to gauze nonwovens and / or formats of the fibers and / or To combine fiber mixtures, according to this method prior to the bonding process, the values of the surface energy of the cellulose fiber are increased by simultaneously increasing the degree of crystallinity and the long identity distance of their surface layer and their crystalline structure of cellulose II or cellulose I structure is converted to the high temperature cellulose IV structure by heat treating the cellulose fiber in a polar, non-cellulose liquid at elevated temperature,
before the bonding process, the molecular chain length in the surface layer of the synthetic fiber used to bind the cellulose is reduced to lower the surface energy, melt viscosity and melting point of the bonding melt produced during bonding from the surface layer of the fiber by subject the fiber surface to a controlled oxidative chain degradation during the spinning stage thereof in the molten state,
prior to the bonding process, the synthetic and cellulosic fibers that participate in fusion bonding are blended using carding or another method known as such and placed in good mutual precontacting to wet the melted portion of the synthesis fiber and the cellulosic surface during fusion bonding, nucleation and to ensure transcrystallization at the interface, which is usually done in roll bonding processes by regulating the linear pressure between the rolls, and in hydroentangling processes, usually by controlling the water needling energy and / or the hydrogen bonding effect between the cellulose fibers,
the peeling of short cellulose fibers from the surfaces of the nonwoven laminates and blended fabrics in addition to the fusion bonding by means of a corona vapor deposition and drying process under pressure, which is carried out as an on-line method after the bonding process, which improves the adhesion by hydrogen bonding becomes.

• – Verbesserung der Haftung zwischen den Cellulose- und Polyolefinfasern wird erhalten, indem die Benetzung zwischen dem geschmolzenen Polyolefin und der Cellulose erhöht wird und indem Transkristallisation in der Polymerstruktur des Abkühlkontaktpunktes bereitgestellt wird. Die Benetzung zwischen den Faseroberflächen wird verbessert, indem die Oberflächenstruktur der Polyolefin- und/oder Cellulosefasern modifiziert wird. Dies erfolgt in Verbindung mit dem Trocknungsverfahren (Durchfluss- oder Saugverfahren) des Wasserstrahlverfestigungsverfahren oder als ein separater, aber On-Line-Prozess.
• – Modifikation der Polyolefin-(insbesondere Polypropylen)faseroberfläche beruht darauf, dass mittels Oxidation beim Spinnen ( FI-Anmeldung Nr. 974169 /07.11.97) Abbau der Molekülketten in der Faseroberflächenschicht in großem Maßstab und entsprechende Abnahme des Schmelzpunkts und der Oberflächenenergie und Viskosität der geschmolzenen Phase, die aus der Schicht erzeugt wird, erhalten wird. Dieses Verfahren wird in Verbindung mit der Fasererzeugung durchgeführt.
• – Modifikation der Cellulosefaseroberfläche beruht in erster Linie auf der Umwandlung der kristallinen Struktur der regenerierten (falls notwendig auch der natürlichen) Cellulose C-II (C-I) in die Struktur C-IV durch Wärmebehandlung derselben in einer polaren flüssigen Phase. Als Folge der Umwandlung nimmt der Wert der Oberflächenenergie der Cellulosefaser zu. Die Modifikation kann in Verbindung mit dem Herstellungsverfahren für die Cellulosefaser durchgeführt werden, indem gesättigter Hochdruckdampf verwendet wird oder, abhängig von den Umständen, als separater Wärmebehandlungsprozess.
• – Eine Folge der Wärmebehandlung der Cellulosefaser (C-I, C-II) in flüssiger Phase ist außer einer Erhöhung des strukturellen Kristallinitätsgrads, welcher an sich u. a. die freie Oberflächenenergie erhöht, die Bildung einer deutlich lamellaren Cellulose-Überstruktur und eine Zunahme des langen strukturellen Abstands. Die Zunahme des langen Abstands und Kristallinitätsgrads der Oberflächenstruktur der Cellulose führt zu einer Zunahme der kristallinen lamellaren Dicke, welche wiederum eine ebene Fläche bereitstellt, welche die kritische Größe übersteigt, die für die heterogene Keimbildung notwendig ist, welche eine Voraussetzung für die Transkristallisation ist (u. a. für das Haftvermögen von Wasserstoffatomen in der Polymerkettenhelix, die zur ebenen Fläche zeigt, an Stellen mit niedriger Energie in der Cellulosestruktur).
• – Die Verbesserung der Haftung zwischen Cellulosefaser beruht auf einer Modifikation der Cellulosefaseroberfläche mittels Hochenergie-Koronabehandlung, um den oxidativen Abbau der Molekülketten in der Cellulosestruktur und u. a. eine Zunahme der Oberfläche mittels mechanischer Bearbeitung, die durch Beschießen mit geladenen Ionen und Elektronen bewirkt wird, zu bewerkstelligen. Die Benetzung des Fasergemischs und Trocknen unter Druck nachfolgend auf die Koronabehandlung führen zu einer sehr wirksamen Zunahme der Haftung durch Wasserstoffbindung. Die Korona- und damit verbundenen anderen Behandlungen werden an einem wasserstrahlverfestigten trockenen Textilerzeugnis durchgeführt. Wenn das Verfahren in Verbindung mit einem Pulpecellulose-Polyolefinmikrofaser-Gemisch verwendet wird, wird ein guter Vorkontakt (vor der Schmelzenbenetzung und Transkristallisation) in dem Cellulose-Synthesefaser-System erhalten. Es ist insbesondere zu beobachten, dass sich die Wirkung der Koronabehandlung an der Oberfläche des Textilerzeugnisses lediglich in eine dünne Oberflächenschicht erstreckt, aber die Bildung der Wasserstoffbrücken die Oberflächenfasern so haften lässt, dass die Cellulosefasern unterhalb der Oberflächenschichten 'verkapselt' sind und das Ablösen von Cellulosefusseln endet. Das Absorptionsvermögen und die Absorptionsgeschwindigkeit eines Korona-behandelten Textilerzeugnisses sind auf Grund des vorstehend erwähnten Mechanismus erhöht. Die Korona- und damit verbundenen Teilbehandlungen (auch die Benetzungs- und Transkristallisationsprozesse) werden als ein On-Line-Verfahren in einem herkömmlichen Wasserstrahlverfestigungsverfahren durchgeführt.
• – Cellulose-Polyolefin-Fasergemische verhalten sich beim thermischen Binden auf eine Weise, die Polymersynthesefasern entspricht, aber die Beteiligung beim Binden der Cellulose in dem Gemisch ist gering (das heißt, die Polymerschmelze bedeckt auch einen sehr kleinen Teil der Celluloseoberfläche, also ohne zukünftige Absorptionsprozesse zu stören). Das thermische Binden von Fasergemischen wird auf eine Weise reguliert, die in dem Patent FI 101087 /1998 beschrieben ist.

Characteristic features of the new process include the following:

• Improving the adhesion between the cellulosic and polyolefin fibers is obtained by increasing the wetting between the molten polyolefin and the cellulose and by providing transcrystallization in the polymer structure of the cooling contact point. The wetting between the fiber surfaces is improved by modifying the surface structure of the polyolefin and / or cellulose fibers. This is done in conjunction with the drying (flow or suction) process of the hydroentanglement process or as a separate but on-line process.
• Modification of the polyolefin (in particular polypropylene) fiber surface is based on the fact that by oxidation during spinning ( FI Application No. 974169 / 07.11.97) degradation of molecular chains in the fiber surface layer on a large scale and corresponding decrease in the melting point and the surface energy and viscosity of the molten phase generated from the layer is obtained. This process is performed in conjunction with fiber production.
• Modification of the cellulose fiber surface is based primarily on the conversion of the crystalline structure of the regenerated (if necessary also the natural) cellulose C-II (CI) into the structure C-IV by heat treating it in a polar liquid phase. As a result of the conversion, the value of the surface energy of the cellulose fiber increases. The modification can be carried out in conjunction with the cellulose fiber manufacturing process by using high pressure saturated steam or, depending on the circumstances, as a separate heat treatment process.
• - A consequence of the heat treatment of the cellulosic fiber (CI, C-II) in the liquid phase is, apart from an increase in the structural degree of crystallinity, which among other things increases the free surface energy, the formation of a clearly lamellar cellulose superstructure and an increase of the long structural distance. The increase in the long distance and degree of crystallinity of the cellulosic surface structure results in an increase in the crystalline lamellar thickness, which in turn provides a flat surface area exceeding the critical size necessary for heterogeneous nucleation, which is a prerequisite for transcrystallization (et al for the adhesion of hydrogen atoms in the polymer chain helix pointing to the flat surface at low energy sites in the cellulosic structure).
• The improvement in adhesion between cellulose fiber is due to modification of the cellulosic fiber surface by high energy corona treatment to accomplish the oxidative degradation of the molecular chains in the cellulosic structure and, among other things, an increase in surface area through mechanical processing caused by charged ion bombardment and electrons , The wetting of the fiber mixture and drying under pressure following the corona treatment result in a very effective increase in hydrogen bond adhesion. The corona and related other treatments are performed on a hydroentangled dry fabric. When the process is used in conjunction with a pulp cellulose-polyolefin microfiber blend, good pre-contact (prior to melt wetting and transcrystallization) is obtained in the cellulose synthetic fiber system. In particular, it can be observed that the effect of corona treatment on the surface of the fabric extends only into a thin surface layer, but the formation of hydrogen bonds causes the surface fibers to adhere so that the cellulose fibers are "encapsulated" beneath the surface layers and detachment of cellulose fuzz ends. The absorbency and absorption rate of a corona-treated fabric are due to of the aforementioned mechanism increases. The corona and associated sub-treatments (also the wetting and transcrystallization processes) are carried out as an on-line process in a conventional hydroentanglement process.
• Cellulosic polyolefin fiber blends behave in thermal bonding in a manner corresponding to polymer synthetic fibers, but the participation in binding the cellulose in the blend is low (that is, the polymer melt also covers a very small portion of the cellulosic surface, ie, without future adsorption processes disturb). The thermal bonding of fiber blends is regulated in a manner disclosed in the patent FI 101087 / 1998.

each Sub-procedure in the process can be regulated in terms of its effect and thus it is possible the final result and the sub-procedures that are selected to achieve the same, to steer.

Both about the Prior art, the applicability of adhesion and Adhesion bonding between synthetic and natural polymer fibers is concerned, and the scientific principles that tie-bonding concern, as well as over the use of cellulosic fibers in nonwoven products made of fiber blend nonwovens by hydroentanglement and thermal bonding processes a short overview will be given.

The statement based on the scientific principles of liability here on the critical observations of S. Wu / 1 /.

The ideal bond strength between two phases is expressed in terms of the adhesion work (Wa) and the equilibrium distance (Zo) between the phases σ ad = K × Wa / Zo, / 1 / where Wa = γ ₁ + γ ₂ - γ ₁₂ and γ ₁ , γ ₂ and γ _{12 are} the surface energies of each phase and their interface.

For typical polymer variable values, a value of only about 104 N / mm ^{2 is} obtained for this ideal strength. In practice, however, strengths are obtained which are an order of magnitude lower. Complete molecular contact, which is a prerequisite for ideal adhesion bonding, is difficult to obtain in practice.

Around to explain the investigated new liability bonding procedure Below is an overview of three, given experimentally proven partial theories, which essentially the Adhesion strength influence.

According to fracture theory, the difference between ideal and actual bond strength results from the fact that the fracturing process is not reversible and there are always defects at the grain boundary and ground planes. The strength of adhesion bonding is determined by the size of the defect and the energy lost in the irreversible deformation during the fracturing process, that is f = K [Eζ / d] 1.2 , / 2 / where E is the Young's modulus, d is the length of the microburst, ζ the energy at break is: ζ = Wa + ψ, where ψ is the total work of the irreversible processes (ψ >> Wa, and therefore ζ - ψ).

To wetting contact theory, van der Waals forces are sufficient to give strong adhesion, provided that it is a molecular Contact between the phases gives and that the contact energies the Extension of the contact at the interface and thus the adhesion influence.

It is assumed that the driving force in wetting the propagation coefficient is λ ₁₂ , that is λ 12 = γ 2 - (γ 1 + γ 12 ), / 3 / where λ _{12 is} the phase 1 propagation coefficient to phase 2. When the size d of an unwetted interface pore is related to the propagation coefficient according to the equation d = D _o [1- (λ ₁₂ / γ ₂ )] ⁿ , where d _o and n are constants, one obtains by substituting into the equation / 2 / the following equation for the adhesive strength f = K [Eζ / d O ] 1.2 [1 - (λ 12 / γ 2 )] -n / 2 , / 4 / that is, the wettability is directly proportional to the adhesive strength, and this fact has been experimentally proven.

The rate of wetting of an interface pore can be expressed as an exponential damping function (d y / D) 1.2 = 1 - α exp (-t / τ), / 5 / where d and d _{y are} the pore sizes at time t and at infinite time, α and τ are constants. By substituting the adhesive strength from the equation / 2 / into the equation / 5 /, one obtains the change of the strength at the time t. It can be seen that the increase in adhesive strength follows first order kinetics, which can also be shown experimentally.

To The diffusion theory is a molecular chain or segment diffusion through the interface the phases a prerequisite for the development of a strong liability bond, which also means: molecular contact with the interface is not sufficient as such out.

A Prerequisite for that the interdiffusion takes place, is the compatibility of the components. However, most polymer pairs are not compatible. The statistical thermodynamics requires that the diffusion movements, those in the interface layer occur, the interfacial energy have to minimize. The thickness of the diffusion interface layer between polymers is inversely proportional to (Flory-Higgins) Interaction parameter. When the compatibility of the components increases, If the interaction parameter decreases, the penetration increases and the thickness of the interface layer is increasing. On the other hand, the interaction parameter is proportional to the square of the difference between the solubility parameters. It was observed that the bond strength between polymers decreases, if the difference between the solubility parameters of the phases increases.

Similar dependencies There is also the wetting contact theory. It is obvious that improving the compatibility between the solubility parameters to a decrease in interfacial tension leads and thus the driving force behind wetting and adhesion increases.

The diffusion kinetics for the formation of an adhesion bond is given by the equation f = 5.5 × V × [(2 ρ 1 / M 1 ) 2.3 D 1 1.2 + (2 ρ 2 / M 2 ) 2.3 D 2 1.2 ] × θ × t (1-β) / 2 , / 6 / where f is the adhesive strength at time t = t, V is a frequency factor, ρ is the density, M is the molecular weight, D is the diffusion constant, θ is the adhesion bond separation rate, β is a constant (often β ≈ 1/2). According to the equation, the adhesive strength increases as the contact time increases, the molecular weight decreases, and the test speed increases. The diffusion can only take place in the presence of contacts. Adhesion bonding may take place in two stages, the first stage comprising wetting to form interfacial contact and the second stage comprising interdiffusion to form a diffusion interface layer. It can be experimentally shown that the adhesion strength still increases after the formation of a complete interfacial contact.

As well can chemical adhesion to the group of investigated processes, affect the adhesion, be counted. The binding energy a chemical bond is typically about 80 kcal / mol while the van der Waals attraction in terms of energy is only 2.5 kcal / mol. It can It can be shown experimentally that the increase of the bond strength as Result of a chemical bond can be 35 times.

at The chemical bonding of interfaces are both coupling agents based on silanes, titanates, chromium complexes, etc. as well of functional groups, such as amino, amide, carboxyl, hydroxyl, Epoxide, isocyanate groups, etc., known.

An important step in the bonding process according to the invention is, besides the polymer / solid material contact and wetting, the solidification of the molten polymer in contact with solid material and the associated phenomena.

The primary Nucleation of spherulites, through surfaces of solid material induced on a well-defined foreign surface is called, is called transcrystallization. The presence prevents many nucleation sites on the foreign surface a lateral growth of the spherulites, whereby the crystallization is perpendicular in one direction only to the nucleation surface can take place. The formation of such a transcrystalline surface layer improves of course the adhesion between foreign surface and polymer and accordingly the strength of the entire composite. In this context will be Factors investigating the transcrystallization process of polypropylene controlling, based on results from critical experimental studies (Goldfarb: / 2 /) is referred to.

The free energy of nucleation for the formation of a rectangular heterogeneous cell ΔG n = -Abl Δg f + 2bl γ + 2ab γ e + al Δσ, / 7 / where a, b and l are the rectangular dimensions, Δg _{f is} the free energy of fusion per unit volume, γ and γ _{e are} the surface free energies per unit surface for the bl and out levels, ΔG is the total free energy of cell formation and Δσ is the energy difference function Δσ = γ cs + γ cm - γ ms , /8th/ where γ _{cs is} the free energy of the crystal / carrier interface per unit area, γ _{cm is} the free energy of the crystal / melt interface per unit area and γ _{s is} the free energy of the melt-carrier interface per unit area. In the case of primary nucleation, the magnitude of the free energy barrier is obtained by differentiating the equation / 7 / with respect to the rectangular dimensions and determining from the differentials the critical dimensions (a *, b *, l *) and these into the equation / 7 / are used, that is ΔG n * = 16 × Δσ × σ e × σ × Tm 2 / (AH f × ΔT × ρ c ), / 9 / wherein the free melting energy is replaced by expressing the melting entropy by a temperature independent term for a material of density ρ _s , Tm is the melting point of the polymer and ΔT is the degree of supercooling (Tm - Tc).

The critical variables for a given polymer are the variables ΔT and Δσ. The impact of the degree of hypothermia is obtained by the specific crystallization temperature and the free energy difference of the carrier surface can be varied by the germinal carrier is varied.

To The measurements almost make crystalline and amorphous surfaces identical nucleation densities ready, showing that the energy difference on the support surfaces, the used in the investigation, of the same order of magnitude is. This is different from earlier ones Investigations, according to which different carriers clearly showed different nucleation activities (ia Schonhorn: / 2 /). In the investigation, to which reference is now made however, special attention to the similarity of magnitude between the carrier surfaces and placed on prevention of poisoning of the carrier. The nucleation densities in the investigation rather put the natural nucleation potential of the used carrier as its effective value.

To estimate the surface energy values of the components of the various supports, the Fowkes / 2 / model is used, which assumes that only dispersion interactions are critical to the hydrocarbon / support interaction, ie, as an example γ ms = γ m + γ s - 2 (γ m d × γ s d ) 1.2 , / 10 / where γ _{ms is} the free energy of the interface of the immiscible phases m and s, γ _m and γ _{s are} the surface tensions of the phases m and s and γ _m ^d and γ _s ^{d are} the surface tensions resulting from the dispersive component of the free interface energy result.

By substituting the partial equations / 10 / into the equation / 8 / and assuming that the components γ _m ^d and γ _c ^d converge, the following equation for the energy difference is obtained Δσ = 2 (γ c - γ c d ) + 2 (γ s d ) 1.2 [(Γ m d ) 1.2 - (γ c d ) 1.2 ] / 11 /

The decisive part of the free energy difference of the carrier is formed from the first, finite, positive constant term 2 (γ _c - γ _c ^d ), the second variable term remaining of lower value compared to the first.

Since specific and identical spherulitic sites are observed after repeated melting and crystallization, it must be assumed that there are a fixed number of active nucleation sites on the support surface. Since the model corresponding to the equation / 7 / requires a planar nucleation surface of the size a × l units, at least these dimensions are required as nucleation conditions. Any material that prevents contact between the carrier and the polymer melt prevents spherulitic nucleation. An impurity component that prevents wetting of the interface or changes the critical dimensions of its planar surface can destroy a nucleation site. On the other hand, active nucleation sites can also be introduced to a 'poisoned' carrier (in one way or another) by increasing the degree of supercooling ΔT. The equation / 9 / was formed from the critical dimensions, where U _i corresponds to the minimum free energy of the system: U i = c i × T m / (AH f × ΔT × ρ c ), / 12 / where the values of c _i for the different dimensions a, l and b were 4γ, 4γ _e and 2Δγ, respectively.

To Equation / 12 / reduces the increase of ΔT the planar dimensions (a, l) for the spherulithic Nucleation are necessary.

It can be further observed that in the investigated temperature range the nucleation densities remained constant, but there were considerable Differences in nucleation activities at different temperatures. The fluctuations of the activities were measured as reciprocal values of nucleation incubation times, and the results of the measurements corresponded to the classical equation for the rate.

• – Transkristallisation ein häufiges Phänomen ist, das stattfindet, wenn es guten Kontakt zwischen dem Träger und der Polymerschmelze gibt
• – die natürliche Aktivität des Trägers unabhängig von seiner chemischen Natur ist
• – die Fowkes-Gleichung für einen Vergleich der Aktivitäten der Träger anwendbar zu sein scheint
• – die klassische Gleichung für die Rate mit den gemessenen Werten für Keimbildungsdichte und Inkubationsdauer übereinstimmt.

As a summary of the investigation can be observed that

• Transcrystallization is a common phenomenon that occurs when there is good contact between the carrier and the polymer melt
• - the natural activity of the carrier is independent of its chemical nature
• - the Fowkes equation seems to be applicable for a comparison of the activities of the carriers
• The classical equation for the rate agrees with the measured values of nucleation density and incubation time.

It are two early Investigations on the transcrystallization of polypropylene Cellulose and graphite fiber surfaces with different qualities affect. The transcrystallization of polypropylene on cellulose fiber surfaces of different qualities (Cotton, Ramiefaser, Fortisan, Reyon, Pulpe) was examined (Gray: / 2 /) by placing them in a thin molten polypropylene film dipped, this film cooled to the crystallization temperature (hot stage) and the transcrystalline crystal growth occurring on the surface Nucleation follows, observed in a polarizing microscope (photographed) has been. The investigation showed that the nucleation is preferable on a natural cellulose surface takes place while an unbleached cellulose surface apparently due to the Presence of hemicellulose and lignin components a worse Nucleating agent is. The surfaces of regenerated cellulose fibers and mercerized cotton very bad nucleation surfaces. Different physical and chemical surface treatments did not induce nucleation on regenerated cellulose. In the Investigations there is no indication of an effect of different crystal morphologies of the nucleation surfaces, but a geometric property of the surfaces on a broad scale could be considered be the transcrystallization controlling.

An investigation concerning polypropylene nucleation on two PAN-based graphite fiber grades (Hobbs: / 2 /) is interesting. A poorly nucleated fiber grade consisted of small unoriented graphite seeds about 25 Å in size, and a good nucleation fiber quality of wide graphite plates that were strongly oriented toward the fiber axis and had a size over 100 Å. The large difference in nucleation properties between these graphite grades appears to be due to differences in the size and orientation of their structural graphite planes. The adsorption of polypropylene directly on the ground plane of the graphite carrier material can be both by the fact that polypropylene crystallizes in a monoclinic lattice system, the molecular chains forming a helical conformation comprising three repeating units, as well as molecular orbital calculations demonstrating which show the preferential adsorption sites for hydrogen on a graphite surface. The helical polypropylene molecular chain can be placed on a graphite lattice surface such that all of the hydrogen atoms in contact with the surface are located in positions of least surface energy (that is, along CC bonds).

The Use of cellulose fibers of different qualities in nonwoven products, produced by methods of thermal bonding of nonwovens are now being investigated.

The method according to the patent US 3,507,943 / 1970, / 3 / is an early innovation concerning industrial thermal bonding of nonwoven webs with wide applicability. In the process, thermal bonding is performed using a pair of rollers wherein one or both of the rolls are embossed and heatable to a desired temperature. In addition to normal thermal bonding, the process of making the nonwoven product includes impregnation, lamination, perforation, flexing, wrinkling, etc. The thermal bond webs typically contain a specified amount of thermoplastic (polypropylene) and absorbent (0 to 75% cotton) bonding fibers. , Rayon pulp fiber) for absorbent wiping products. Nonwoven and woven fabrics, organic film, paper, tape, etc. are used as substrates in lamination.

The patent US 3,501,369 / 1970, / 3 / relates to a nonwoven product and a process for its production. The novel nonwoven product having high wet and dry strength values consists of a thermally bonded polypropylene-cellulose fiber nonwoven, wherein the proportion of the cellulose fiber is 25 to 95 wt .-%. The cellulose fibers are either short natural fibers (including cotton) or synthetic fibers (including rayon). The manufacturing method comprises producing a nonwoven fabric from the fiber blend, heating (163 to 204 ° C), and bonding under pressure (36 to 360 kg / m) of the nonwoven fabric by hot or cold rolling.

According to the description The binding polypropylene fibers in the product are the cellulose fibers winding around and lending the produce, in part, to each other fused, strength, that is, the bonding of the cellulose fibers is mechanical in the first place. Due to its absorption capacity is the product for wiping, for surgical applications, etc. well suited.

JP Moreau / 4 / examined thermal bonding of polypropylene-cotton blends (20, 30, 50, 75, 100 weight percent PP) as a function of temperature using a pair of rollers, one stamped and the other smooth , The bonding speed of the nonwoven fabric was 30.5 mm / s and the linear pressure between the rolls was 66 kN / m. The weights of the bonded nonwovens were 40, 60 and 80 g / m ² . The mixing of the cotton and polypropylene fibers proved difficult in the test series. The use of a cotton-fleece film-bonded polymer resulted in a better polymer-cellulose distribution as compared to a fiber blend. A cotton fiber-polymer film laminate gave better values for longitudinal and transverse strength as compared to a corresponding blended fiber product. The breaking strength, elongation, stiffness and absorbency of the products were measured and the effects of blend levels, surface area of the product and temperature on the properties of the product were determined using statistical analysis. It can be mentioned that the values for the tensile strength given in the tables of the publication by Moreau (/ 4 /, 1990), the regulation equation for the thermo-bonding model according to the FI patent application 961252 / 18.03.96, / 5 / in a satisfactory manner. The thermal bonding regulatory equation for the web which simulates the measurement results of the publication in terms of MD tensile strength is σ = 5.476 × 10 12 × [PP] 1,131 × exp [1,045 × 10 -2 × w × T 2 × exp [-36010 / RT], / 13 / where σ is the tensile strength of the fabric in N; [PP] is the polymer content of the fiber mixture in% by weight; w is the weight of the fabric in g / m ² ; T is the oil temperature of the roller in k and E is the dimension for the activation energy in cal / mol.

TF Gilmore et al. / 1992, / 4 / in their paper examine the benefits, uses and improvements of the use of cotton in nonwovens. Here, thermal bonding is an economical and important alternative to hydroentangling processes which, as is known, best retain the beneficial textile properties of cotton in the product. In particular, the use of heterophilic bicomponent fibers as bonding fibers in thermal bonding yields Er in this case products with good textile and strength properties. In the experimental section of the publication, thermal bonding of a cotton nonwoven fabric is carried out using a polypropylene-polyester bicomponent fiber (20% by weight in admixture). The thermal bonding tests were conducted as a function of the linear pressure between the rolls and the temperature, the nominal weight of the fabric being 85 g / m ² . The duo and trio rolls were used in the bond tests wherein the mat transports in the forward direction over a hot, embossed and hot, smooth roll and the pre-bonded fabric in the reverse direction over the aforementioned hot, smooth and unheated elastic rolls has been. As a result of the investigation, it was observed that trio-rolls did not provide appreciable advantages compared to duo-rolls. According to the publication, it is believed that the binding mechanism is based on mechanical attachment or encapsulation of cotton by polypropylene.

The Use of cellulose fibers in products made by hydroentangling process available are known. Some examples from the very broad state of the Technology that affects such processes and products mentioned.

The method and the products according to the patent US 3,485,706 / 1969, / 3 / are often regarded as the pioneering inventions in the industrial application of liquid-needling processes. The process uses either cellulosic fibers as such or in admixture and laminates with synthetic fibers. Cotton and rayon fibers in the first place and also short pulp cellulose fibers in the form of tissue paper are used as cellulosic fibers. There are a variety of synthetic fibers (polyester, polyamide, polyacrylic, polyolefin fibers, etc.), homo- and copolymer fibers either as one- or two-component fibers, continuous fibers or staple fibers.

In the hydroentanglement process according to the patent US 4,442,161 / 1984, / 3 / produces nonwoven products with improved liquid barrier properties. The method uses both a row of nozzles that are more dense than normal and a combination of sprayers including the use of high and low pressures. The process uses polyester fibers either in the form of continuous fibers or staple fibers and pulp fibers primarily in the form of harmac paper. The nature of the bond between the cellulose and the synthetic fibers is believed to be completely mechanical. Examples of the process indicate the "self-bonding" temperatures of the polyester grades, but apparently for the selection of drying temperatures for the products.

In the method according to the patent US 4,902,564 / 1988, / 3 /, a high strength, high-absorbency, surface-treated wiper (100 to 270 g / m ² ) is prepared from a fiber blend containing 50 to 75 weight percent wood pulp and 25 to 50 weight percent synthetic fibers. In the process, the wet laid web is subjected to hydroentanglement. It is particularly advantageous to use pulp fibers with a length of 3 to 5 mm, since these show the best performance in needling and the products have both the best tensile and abrasion resistance and sufficient wet strengths. In the process, polypropylene, polyamide and polyester fibers are used as synthetic fibers. The bond between the fibers is completely mechanical.

The invention according to the patent US 5,459,912 / 1993/3 / comprises both hydroentanglement fabric articles made from synthetic fibers and pulp fibers and a method of making same.

The fabric products have very low wet and dry particle counts and good absorbency. The minimum particle number is given as dry as 2.83 x 10 ⁵ per m ³ and wet as 6.5 x 10 ⁷ per m ³ and the minimum absorption rates as 0.1 g / g and 300%, respectively. The pulp content of the fabric is 5 to 50% by weight. Polyester, polypropylene, polyamide and polyacrylic fibers and combinations thereof are used as synthetic fibers.

In a first step of the manufacturing process according to the patent, a nonwoven comprising cellulose and synthetic fiber layers is needled with the synthetic fiber layer to the wire net (maximum: 75 mesh) at a die pressure range of 6.9 to 138 bar, the total energy of the pin jet is at least 50 kJ × N / g. During the needling, the fibers in the pulp layer are hydraulically entangled with the fibers in the synthetic fiber layer. In a second step of the process, the resulting premixed nonwoven is supported with its pulp side on an apertured embossing apparatus with an opening number in the range of 40 to 10 mesh and is fired using a total energy of at least 53 kJ · N / g water needles. During the needling, the fibers are moved in the lateral and vertical directions from their initial positions towards the openings in the embossing device (ie, the wire net), thereby producing an impression on the fabric. The speed of the wire mesh in the hydroentangling process is at least 18 m / min (in the range of 90 to 180 m / min). In order to improve the absorbency properties of the fabric, water removal under reduced pressure is performed in the process with the fabrics.

With regard to the product and the methods according to the patent US 5,459,912 It can be concluded that they do not include anything significantly new in terms of older known products or applied hydroentanglement technology. An indication of the maximum particle count values for the products does not clearly define the quality of the fabric in terms of cellulosic stripping, as the fibers emanating from the fabric have both size and weight distributions. Since there is no correlation between the used (non-standardized) particle measurement method and other measurement methods (among other things based on the weight change of the sample of the fabric), it is impossible to compare the products obtained with the method with the known prior art to perform the technique.

In the limited study of publications that are binding of cellulose and Synthetic fibers did not become a process or regulatory procedure found that is comparable to the new method to the adhesion bond between fibers of different qualities.

Some Operating principles representing the new combination of regulatory procedures used in the manufacture of nonwovens becomes detailed examined in the following examples.

Sub-example 1

in the Subexample 1 describes both the structure of cellulose fibers also the kinetics of the polymorphic changes in the cellulose and their effect on the fiber structures in conjunction with the Regulatory procedure using X-ray wide-angle and small angle scattering (WAXS and SAXS) and heat treatment tests examined. In the examples will be in conjunction with the new innovation an increase in the energy level of the surface layer of the cellulose fibers as a result of lattice transformation, increase in degree of crystallinity and exceeding the critical minimum size of the adhesion surfaces, these functions are partly related to each other.

• – native Cellulose, das heißt Cellulose I (C-I), die in den meisten natürlichen Fasern vorkommt, wie Baumwoll-, Holz-, Ramie-, Leinen- und verschiedene Hanffasern.
• – Hydrat-Cellulose, das heißt Cellulose II (C-II), wobei diese Form u. a. in regenerierter und mercerisierter Cellulose vorkommt.
• – Hochtemperatur-Cellulose, das heißt Cellulose IV (C-IV), die bei erhöhter Temperatur in Gegenwart einer polaren flüssigen Phase sowohl aus nativer als auch Hydrat- Cellulose hergestellt werden kann.

Three polymorphic forms of the cellulose crystal structure are linked to the present innovation, namely

• - native cellulose, ie cellulose I (CI), found in most natural fibers, such as cotton, wood, ramie, linen and various hemp fibers.
• Hydrate cellulose, ie cellulose II (C-II), this form occurring inter alia in regenerated and mercerized cellulose.
• High temperature cellulose, ie cellulose IV (C-IV), which can be prepared at elevated temperature in the presence of a polar liquid phase from both native and hydrate cellulose.

The celluloses I and II are monoclinic with respect to their crystal lattice form, and they differ from each other primarily with respect to the lattice constant c and the angle β of the (a / c) axis. The lattice form of cellulose IV was not confirmed, but it is considered to be tetragonal or orthorhombic. The lattice constants of the cellulose lattices C-IV and CI are very close to each other, but the C-IV lattice lacks the plane-plane reflex (10 1 ). Table 1 shows both the lattice constants for the cellulosic qualities and the important reflections of the planes corresponding to the Miller indices calculated therefrom. Apart from the identification based on the WAXS scattering of the cellulose lattice forms, the degrees of crystallinity from the samples were determined in the angular range of 2θ = 10 to 30 °, based on the sum of the scattering intensity.

To determine the cellulosic structures, WAXS (and SAXS) measurements were made on both natural fibers, raw cellulosic fibers, tissue paper and regenerated cellulosic fibers made in different manners, as well as on corresponding cellulosic films. The cellulose samples differed substantially in their degrees of crystallinity, with the degree of crystallinity of regenerated cellulose fibers (C-II lattice: 23 samples) being substantially lower than that of natural cellulose fibers: cotton: 68 to 70%, pine aspen cellulose: 53 to 65%, Xanthat-based Reyone: 35 to 40%, NMMO-based rayon: 50 to 55% and carbamate-based rayon: 35 to 45%.

The structural change C-II (C-I) / C-IV in the crystal lattice of cellulose fibers depends on many factors in addition to fiber quality from. Generally speaking, the transformation is more complete, the lower the crystalline order and the less energy required for this is. Thus, a structural change is for regenerated cellulose fiber (C-II) easier than for mercerized or untreated natural fibers (C-I).

Reyonviskosefaser in dry form is structural up to a temperature of 300 ° C almost unchanged, but when in liquids is treated in a temperature range of 140 ° C (80 ° C) to 300 ° C, takes the Degree of conversion C-II / C-IV as the polarity of the liquid increases increases. While Mercerizing the cellulose molecules from each other under the influence separated a swelling agent, which makes the anhydroglucose molecules easier during the conversion back turn to the down-grid level.

In the method according to the new Innovation is the necessary C-II / C-IV conversion level low as it is the target is a thin one To obtain cellulosic IV layer with high surface energy on the fiber surfaces.

The concentration ratio of the crystal phases C-IV / C-II was measured for viscose fibers by means of the respective WAXS intensity ratios (inter alia the intensities of the (101) plane reflex) after both glycerol and water autoclaving. The following equation was obtained to simulate the intensity ratios with sufficient accuracy (in this connection). I (C-IV) / I (C-II) = F exp [-E / RT], / 14 / wherein for the examined viscose fibers, the value of the activation energy E = 4676 cal / mol, the constant F depending on the fiber quality. For the constant F, the following values were obtained for two Xanthat-based fiber grades A-71 and C _s -88: F = 381.3 and 194.6. For the fiber quality L-71 regenerated from a NMMO solution, the value F = 213.4 for the constant was obtained.

The Scatter intensity ratio of (101) levels of fiber quality A-71 was in glycerol after heat treatment at a temperature of 226 ° C S = 5.05 (Equation 14: S = 4.85), which corresponds to a degree of conversion of about 90% in the crystalline part of the structure and thus a C-IV concentration of 57.6% in the crystalline part (the degrees of crystallinity before or after the heat treatment were 38 and 64%, respectively). The fiber quality L-71 has a scattering intensity ratio which is lower than the previous one (2.71), but its degree of crystallinity is higher than the former (before or after treatment 55 or 70%), which is why the C-IV concentrations of the fiber qualities are not very different differ.

It It should be noted in this context that due to the effect the heat treatment in a polar liquid u. a. the degree of crystallinity of cellulose II increases to the degree of crystallinity of Cellulose I corresponds. The degree of crystallinity of cellulose structures elevated not when heated in dry form. The effect of the heat treatment duration on the C-II / C-IV conversion was so small according to the measurements (+ ~ 0,5 - 36 h), so that it does not appreciably affect the intensity ratio, you draw u. a. the error in the degree of crystallinity into consideration. It is observed that the procedure in this context used to measure C-IV / C-II concentrations, first Line qualitative values, since u. a. the increase in the degree of crystallinity for both Crystal systems as a function of temperature (and duration) of different order of magnitude is, and the degree of crystallinity used in the, fast Measurement technology is inaccurate.

Around the C-I / C-IV lattice transformation of the crystal structure of dry naturally To investigate cotton (C-I), some heat treatment tests were carried out in glycerol (200 ° C / 2 h). The heat treatment yielded lower intensity ratios as in the aforementioned C-II conversion, but from the WAXS analysis was slightly a shift the (C-I) scattering intensity the (101) plane towards larger 2θ values and Note the disappearance of the (C-I) scattering intensity of the (101) plane when the C-IV lattice forms.

Cellulose lattice C-IV is not a polymorphic form of cellulose in exactly the same proportion as lattices CI and C-II, but C-IV is more unstable than these and can be considered a defective and unorganized form of cellulose-I. On the other hand, in the cellulose C-II / C-IV conversion, there is a change in the cellulose superstructure to a more organized lamellar structure, which is easy with X-ray small angle scattering ungsmessungen can be shown.

SAXS-analysis of both natural (C-I) as well as regenerated (C-II) cellulose fibers generally shows one monotonically decreasing intensity (I) / scattering angle (Ε) function. A periodic lamellar structure perpendicular to the grain, which is common in synthetic fiber polymers, so is cellulose fibers not often to watch. The bad education and recognizability of the long identity gap in Cellulose fibers are both low and density differences between the crystalline areas as well as in particular the channels between the amorphous areas and microfibrils that are in the direction arrange the fiber axis (inter alia cotton and corresponding structures), attributed.

In partially broken (among other things swollen with alkali solutions) cellulosic structures break points and break points in the scattering function can be seen, especially when a Lorenz correction (I ε ² / ε-function) is used for the scattering results.

at the carried out SAXS scattering tests used samples of production fibers. Thus, in part for practical reasons (crimping, preparation of the sample etc.) the scattering result does not reflect cases in which the radiating plane is exactly vertical to the fiber axis, as a part of the test fibers a complete one has different direction.

In the SAXS diagrams of cellulose fibers in their ground state, there was a more or less sharp peak or anomaly in the ε ² / ε function for both natural and regenerated fibers in the scattering angle range ε = 17 to 19 mrad, which is a Bragg distance L (Z) = 45 to 40 Å. In the SAXS plot of regenerated cellulose fiber, in addition to this line, there was also a well-defined peak corresponding to the scattering angle ε = 1.0 ± 0.5 mrad, that is, (L) Z = about 771 Å. For cotton fibers, a weak anomaly of the scattering behavior was also observed in the range: ε = 9 to 11 mrad and L (Z) = 86 to 70 Å.

cotton and rayon fibers (IS and A-71) were in a thermostat (200 ° C / 4 h) in a nitrogen atmosphere heat treated. The heat treatment led no noticeable changes the WAXS scattering angle of the lattice planes of the samples compared to the output fibers. A slight increase in the degree of crystallinity could be determined on the samples: IS: 69 → 71% and A-71: 40 → 42%. at SAXS scattering of dry, heat treated, regenerated Cellulose fibers there were no significant changes compared to the Output fibers. However, the scattering function of cotton fiber showed increased Intensity, the scattering angle ε = 7,5 mrad, that is L (Z) = 103 Å, equivalent.

As stated earlier, at elevated temperatures, polar liquids cause a change in the crystal structure from the C-II and CI form to form C-IV and, associated therewith, a substantial increase in the degree of crystallinity, especially of regenerated fibers. At the same time, substantial organization of the cellulose superstructure takes place, as indicated by sharpening the intensity peaks of the SAXS scattergrams and corresponding realization of the lamellar structure. As the treatment temperature increases, the maximum values of the Iε ² / ε functions shift toward small scattering angles and a corresponding increase in the values of the 'long identity distance' L (Z). As the degree of crystallinity of the structure increases significantly at the same time, the increase in lamellar distances means a substantial increase in the lamellar thickness. The change of the long distance as a function of temperature followed the form of the following equation L (Z) = -M + N / (θ O - θ) / 15 /

The value of the constant N was constant for rayon fibers within the limits of measurement accuracy, that is N = 43390 Å / ° C. Likewise, the "character" temperature θ _{o was} constant, that is, θ _o = 414.5 ° C. The value of the constant M was a function of fiber quality (also for cotton fibers.) For the xanthat-based rayon fibers A-71, the Value for the constant M = 110.2 Å. For the exemplary temperatures, the length of the Lorenz corrected long distance was: L (Z), Equation measurement / ° C: 182.0 to 181.4 / 266, 144.3 to 140 , 2/244, 94.0 to 102.0 / 202 and 44.5 to 42.8 / 134.

When an example will be the M values for three Xanthat-based ones Fibers mentioned: 120.9 / Lnz, 145.4 / Cs-88 and 110.8 / Cs-75. For a on NMMO solvent based rayon fiber L-71 was the value of the constant M M = 150.2 Å, that is the values for the long distances were much lower than for the fiber A-71.

When a general result of the SAXS analyzes can be determined in particular by regulating the heating temperature in the polar liquid (where the heating time of lesser importance) is the crystalline lamellar thickness The cellulose can be regulated, reducing the critical dimensions the nucleation levels for the heterogeneous nucleation of the cellulose surface can be exceeded.

Sub-example 2.

in the Sub-example 2. will involve the wetting of cellulose surfaces molten polypropylene, spreading of the contact melt and kinetics the spread in connection with the new method.

A requirement for a strong adhesion between a cellulose surface and Polypropylene is the formation of a sufficient contact surface during one sufficiently short, technically easy to realize time span. These requirements have on the one hand sufficient wetting between the cellulose surface and polymer melt, one enough rapid spread of the melt on the contact surface and accordingly during the solidification of the polymer melt the provision of epitaxial "grain boundary crystallization" (transcrystallization) as a condition.

In In this context are the level of not very well known surface energies the different structural surface forms of solid cellulose and due to the strong polarity of cellulose the quality of the energy of importance, which is why the measurements are primarily to enlighten these.

The driving force for the spontaneous propagation of a liquid on a solid surface consists of non-equilibrium interface forces, that is f d = γ SV - γ SL - γ LV cos θ, / 16 / where f _{d is} the driving force acting on a unit length of the liquid front, γ _{SV is} the surface tension of the solid with the saturated vapor of the liquid, γ _SL is the interfacial tension between solid and liquid, γ _{LV is} the surface tension of the liquid and θ is the instantaneous Contact angle is.

By applying the Young Equilibrium Equation in the equation / 16 / one obtains / 1, 12 /: f d = γ LV (cos θ e - cos θ), / 17 / where θ _{e is} the critical angle corresponding to the equilibrium state.

Due to the additivity of the energies between the molecules generated by the nonpolar and polar components, the following equation for the generation of interfacial energy (γ _SL ) is obtained γ SL = γ SV + γ LV - 4 (γ S d · γ L d ) / (Γ S d + γ L d ) - 4 (γ S p · γ L p ) / (Γ S p + γ L p ), / 18 / which is obtained by applying the Tonng equation γ LV (1 + cos θ) = 4 (γ S d · γ L d ) / (Γ S d + γ L d ) + 4 (γ S p · γ L p ) / (Γ S p + γ L p ), / 19 / where γ _S ^d , γ _L ^d and γ _S ^p , γ _L ^{p are} the dispersive and polar components of the solid and liquid surface tensions. In this context, the harmonic mean (/ 19 /: partly empirical: S. Wu) is used in combining the dispersion and polar forces of the solid and liquid phases because the cellulose surface is highly polar and the normal geometric mean is therefore for use is unsuitable.

The empirical measure, that is, the critical surface tension γ _c , the wetting of a solid surface developed by Fox and Zisman / 12 /, is very useful. It has been observed that the function provided by a series of homologous liquids on a solid substrate is cos θ / γ _LV , generally a straight line which, when extrapolated to the value cos θ = 1, has a specific surface tension γ _LV , which is the critical stress γ _c . Thus, liquids with a smaller surface tension than γ _{c spread} on the solid surface.

In the examinations of the subexample were glycerin, formamide, Methylene iodide, tetrabromoethane, α-bromine and α-chloro-naphthalene as organic liquids for the Measurements of the relationships between the surface energies for cellulose used, with these fluids the first two are strongly polar. The surface tensions of the liquids and their dispersive and polar components corresponded to the values in the known literature (Wu, Toussaint-Luner: / 12 /).

The regenerated cellulose fibers used in the study were based on xanthogen and N-methyl-morpholine oxide (A71 and L71 type) and also purified cotton. Part of the examined Fibers became in polar liquids heat treated. The cellulose fibers were conventional, industrial Qualities, from which the finishing agents had been extracted. The heat treated Fibers were surface cleaned with an ethanol-ether solution. The measurements of the dynamic contact angle were measured with an analyzer Cahn DCA-322 using liquids carried out.

From the contact angles measured in non-polar liquids, the following critical surface energies were obtained for the cellulosic fiber grades A-71 and L-71 as well as for the natural cotton fibers PV: γ _c , MJ / m ² : 33.5 and 39.5 as well as 39.8. Scattering of the measurements was considerable, but their effect on the critical surface energy values is not significant. The measured values obtained correspond fairly well to the values from the literature.

The measured values for both regenerated cellulose (CI structure) and hemicellulose were with their numerical values and also their cos θ extrapolation lines with the cellulose quality A-71 (Luner et al .: Woodcast, Avicel: γ _c = 35.5, Cottoncast : 41.5, SW-xylan: γ _c = 35, etc.). The values for the critical surface energy of cotton and pulp fibers (CI structure) vary in the literature depending on the polarity values of the measurement solutions used. For Douglas pulp fibers, a value (Nguyen et al.) Of γ _c = 52.9 is given when measured in polar liquids, and a value of γ _c = 39.3 when measured in non-polar liquids. For cotton, the value γ _c = 38.6 mJ / m ² is obtained by calculation from the γ components (Westerlind et al.) In non-polar liquids.

As a result of the heat treatment in polar liquids (glycerol, water), the values of the critical surface energy (measured in non-polar liquids) for the samples from the test series A-71 and L-71 increased considerably:
γ _c , MJ / m ² / γ, ° C:
A-71: (CH ₂ ) ₂ CH (OH) ₃ : 33.5 / 21, 37.5 / 200, 37.0 / 202, 39.5 / 222, 44.1 / 244 and H ₂ O: 37 , 8/145
L-71: (CH ₂ ) ₂ CH (OH) ₃ : 39.5 / 21, 43.1 / 202, 41.6 / 222, 44.2 / 244 and H ₂ O: 39.7 / 145

Also if, based on the above explanation, should critically refer to the critical surface tension, It is clear, based on the test series, that the surface energy a cellulose fiber surface as a result of the heat treatment in polar liquids increases, the order of magnitude the increase decreases as the degree of crystallinity of the output fiber increases. The critical surface energy A regenerated cellulose fiber thus approaches the corresponding one Values for natural fibers as a consequence of the lattice transformation caused by the heat treatment is caused.

If the critical surface energy is determined in non-polar liquids, it could be concluded that by applying the harmonic method of Wu, only a portion of the surface energy component values obtained would be comparable to the corresponding literature values. For the sake of comparison, some calculated γ _s ^d and γ _s ^p values for a cellulose surface are shown in Table 2. From the results, it can be seen that the dispersive component of the surface energy approximates the corresponding literature values. The polar component of the surface energy of the samples tested is smaller than normal, except for cotton. The low levels appear to be attributed to impurity components left on (or added to) the surfaces of the cellulosic technical fibers which affect polarity (there are often hemicellulose or lignin residues even on natural cellulose surfaces). Table 2 contains some surface energy values obtained for cellulose films coated with alkylene ketene dimer (Toussaint et al. / 12 /: 1.6-2.1-2.4 μg AKD: the hydroxy groups up to 36% of the surface has been replaced by AKD molecules), which can be seen as a large reduction in the polar component of the energy as a function of the "degree of coverage" of the surface, with the dispersive component remaining substantially constant.

In addition, the values (mJ / m ² ) of the driving force (fd) of the spreading and the adhesion work (Wa) corresponding to the measured values shown in Table 2 are given for a polypropylene melt / cellulose system:
fd-Wa / fiber: 6.15-48.9 / PV-1, 5.58-48.3 / A-71-LK-200 ° C, 9.23-52.0 / A-71-LKA 145 ° C and 11.7-54.2 / A-71-LK-244 ° C.

Based on the results of the surface energy measurement Can generally be concluded that except for cotton the values of the surface energy of cellulose surfaces and polypropylene melt so close together that the effect controlled by contaminating components in measurements of surface energy must become. In a technical area, the impurity residues or additions in cellulose and be used in the control of the process.

In addition to clarification, clearing up of something The relationships between the surface energies is a task the investigation in the sub-example the rate of propagation of a Polyolefin melt on cellulose surfaces, which of considerable Importance with regard to the realization and regulation of the Liability process is. The measurements showing the spreading of the polymer were carried out, by varying a quantity of the polyolefin of about one milligram on cellulose surfaces qualities (regenerated, grafted cellulose films and thin compressed pulps from natural Cellulose) was applied by melting the polymer and using a protective gas oven with thermostatically controlled heating table to the desired Temperature was brought. The spreading of the molten drop was as a function of duration and temperature with a CCD camera photographed, the information was loaded onto a magnetic tape and the measurement of the recordings took place using image analytical Procedure instead. The change the contact angle of the solidifying melt and the end contact angle, when the polymer was in a solidified state, for control reasons as well measured with a contact angle analyzer.

The kinetic analysis of the spreading of the polymer was carried out according to the attached study / 1, 12 /. By combining the equations for the spontaneous propagation of a liquid on a solid support material and that for the deceleration force resulting from the viscosity of the liquid, the following equation for the rate of change of the cosine of the wetting angle of the system can be obtained: d cos θ / dt = [γ L · ΗL] [cos θ e - cos θ], / 20 / where θ _{e is} the equilibrium contact angle, γ _{L is} the surface energy of the fluid, η is the viscosity of the fluid, and L is the scaling length.

The equation / 20 / in integrated form is hereby l - cos θ / cos θ e = a × exp [-ct], / 21 / where c = γ _L / η · L and a = l - cos θ _o / cos θ _e and θ _{o is} the contact angle at the starting point (t = 0).

According to the equation / 21 /, the reaction rate of the change in the cosine of the contact angle is directly proportional to the surface tension of the wetting polymer melt and inversely proportional to its viscosity at low shear rate. The temperature dependence of the polymer surface tension is low, which is why the temperature dependence of the rate coefficient investigated is determined primarily by the activation energy of the polymer melt viscosity (PP: E ~ 8000 cal / mol). The polymer surface tension only moderately depends on the molecular weight, except for its low values (Mn <5000). The effect of molecular weight on polymer melt viscosity above the so-called critical molecular weight (PP: M _W , c ~ 5,000) is quite considerable. In the low shear rate region (D = 1 s ^-1 ), the viscosity of the polypropylene melt can be characterized by the equation η = M W 3.49 × 4,720 × 10 -20 × exp [8000 / RT], Pa · s / 22 /

By regulating the surface energy of the polymer (additives), it is possible to influence its propagation rate on a solid surface to a small extent. By regulating the viscosity of the polymer, the rate of wetting of a solid surface can be remarkably controlled by reducing the weight average molecular weight of the wetting polymer, where by being able to exploit simultaneously the reduction of the melting point of the polymer / 14 /. In practice, it is possible to cause degradation of the molecular chains in the surface layer of the polyolefin fibers by oxidation when spinning in the molten state in conjunction with fiber spiders.

The Propagation of a polymer melt on the surface of a solid material may be due to a number of structural factors of the solid or by natural or added chemical impurities on its surface (lignins, Hemicellulose, finishing agents, etc.) as well as mechanical barriers the solid surface be determined.

The kinetic measurements of this subexample specifically investigated the behavior of conventional, often impure cellulose surfaces in conjunction with the spread of a molten polypropylene droplet. The measurements did not detect any primary or secondary edge films that precede the spread of the drop. Primary due to film contamination and irregularities, equilibrium contact angles were not sought in the investigations, but an angle was selected as the contact angle value (θ _e ) where dθ / dt appeared to be constant. For the values that are needed in practice, the procedure can not be noticeably wrong. The results from some propagation tests are given in Table 3. Of the films in the table, films Nos. 1 and 2 are cellulose carbamate-based C-II films. The nitrogen contents of the films are 1.6 and 0.18%, respectively. The nitrogen sits as an isocyanic acid additive on the 6-carbon of the cellulose (CH ₂ OC-NH ₂ : / 16 /). Film # 3 is a cellulose xanthate based C-II film. Of the samples in the table, Cellulose Samples Nos. 14 and 22 are bleached and unbleached fine cellulosic fiber (CI structure).

at The kinetic studies are based on the MWD analyzes of the treated polypropylene grades the attached Table. In the table are also the viscosities according to the formula / 22 / at the temperature from 180 ° C specified. The table contains also the values of the relative rate constant for the wetting rate constant for the Sample pair, the bleached cellulose fiber (# 14) of the Table 3 corresponds, as calculated from the viscosity values, as well as the time required to increase the θ value according to the rate equation / 21 / to reach.

• MFR: ASTMD 1238

Sample Nos. 9 and 3 of Table 3 are different from each other primarily in terms of the molecular weight distribution of the polypropylene melt. Their rate constant ratio C (3) / C (9) = 3.24 should therefore be inversely proportional to the ratio of the corresponding viscosities. According to the attached table, the viscosity ratio η (22) / η (21) = 4.65, so there is a sufficient correspondence between the rate constants and the viscosities. sample MFR g / 10 min MWD M _W - D η Pa · s c min ^-1 t (70) s PP 21 350 124450 - 3.86 207 0.606 52 PP 211 800 98410 - 4.44 91 2,269 14 PP 22 26 193300 - 5.53 960 0.215 146 PP 23 4.4 407500 - 7.00 12970 0.016 1927 'PP 24' - 50000 8.6 24 1.3

• MFR: ASTMD 1238

It can be mentioned be that according to the table 3. the ratio between the rates of change of wetting angles Sample pairs Nos. 3 and 9 (at the point θ = 70 °) and times around the contact angles to reach 4.48 and 4.14, respectively.

According to the results in Table 3, the rate coefficient of wetting for the bleached cellulose fiber (# 14) is slightly higher than that for the unbleached (# 12). In the attached table, the change of the rate coefficient corresponding to the bleached cellulose fiber (CI structure) was calculated when the values for the weight-average molecular weight of the wetting polymer and, accordingly, for the melt viscosity change to values both higher and lower are as those of the reference polymer. The molecular weights of the surface layers of peripherally oxidized polymer fibers are / 15 / in the range of M _W = 500,000 → <10,000. Thus, it is by regulating the molecular weights of fibers oxidized from conventional engineering polymers or spun Fibers are made possible to regulate the rate, degree of wetting and wetting durations between a polypropylene melt and cellulose over a very wide range in a field of operation that is technically easy to implement. From the results shown in Table 3, it can also be seen that the carbamate-based nitrogen content of the sample films (1 and 2) has a lowering effect on the rate constant of wetting, that is, in comparison with that of Figs Xanthate-based film (3) in a nitrogen and air atmosphere:
N ₂ : 0.00 N / Nos. 15 / C (15) - 0.18 N / No. 16 / 0.63 × C (15) - 1.60 N / Nos. 3 / 0.41 × C (15)
Air: 0.00 N / No. 6 / C (6) - 0.18 N / No. 5 / 0.84 × C (6) - 1.60 N / Nos. 4 / 0.79 × C (6)

In an air atmosphere take the rate constants for the wetting in all test series compared to the values in a nitrogen atmosphere from. Another important effect of an air atmosphere is that almost complete Disappearance of the lowering effect on the rate constant of the structural Nitrogen in the film (the impurity component of the film is oxidized and evaporated, the film surface is oxidized, etc.). When Oxygen in the air also decreases in value for the equilibrium contact angle in the samples of the test series. The effect of both the structural Nitrogen in the film as well as the atmospheric Oxygen on the rate of wetting is a result of changes at the components of surface energy. By regulating the values of the surface energy, it is possible, the to influence kinetic characteristics during wetting, but obviously to a lesser extent than by regulating the viscosity the polymer melt.

It may also be mentioned that, when the contact samples were cooled after the wetting measurements, it could be observed that the temperature of the solidification was even 30 ° C above the conventional solidification temperature (~ 110 to 115 ° C), the degree of Hypothermia of the polymer melt decreased accordingly. This is a consequence of heterogeneous nucleation of the polymer melt on the cellulose surface. It is also observed that this nucleating effect of cellulose decreased as the molecular weight of the polymer increased; For example, in the attached table, the polymer PP 23 had a melt solidification temperature (air atmosphere) of 113 ° C, the polymer PP 22 (N ₂ ) of 133 ° C, and the polymer PP 21 (N ₂ , No. 3) of 142 ° C ,

Sub-example 3.

in the Sub-example 3. was the thermal bonding of fiber mixtures made of regenerated cellulose fibers of different quality, cotton fibers and conventional Polypropylene fibers and those of skin-core type examined to the main ones To clarify bonding effects between the fibers.

The apparatuses and their functions and the methods for operation, control and regulation of the thermal bonding, water-needling and spin-oxidation processes used in the manufacture of the fabrics and fibers in Sub-Examples 3 and 4 are discussed in detail in US Pat the patents FI 95153 ( EP 0 667 406 A1 ) and FI 101087 ( EP 0 799 922 A1 ) and the FI Patent Application Nos. 953288 / 030795 ( EP 0 753 606 A2 ) and 974169 / 071197. For the verification of the binding results for the test textile products, a binding equation of the form ( FI 101087 ) Φ = c × T 2 × exp [-E / RT], / 23 / which simulates the measurement results well, with a strength characteristic of the fabric being: longitudinal and transverse tensile strengths, elongation, fracture energies, etc., T is the absolute temperature, c is a function of web speed and weight, draw ratio in fiber manufacture, chain orientation and molecular weight distribution of the fabric Fiber polymer, proportion of binding fibers in the fiber mixture, etc. is.

The bonding equation is satisfactorily applicable for use in the temperature range of the fabric (that is, at a temperature above the temperature T _m, corresponding to the bonding strength maximum δ _m, wherein the proportion of the partial melt of the binding polymer is high).

The first test series (A) of Sub Example 3 was carried out using a pair of steel rollers with a dot-patterned and a smooth roller. The results of the test series using the binding equations are shown in Table 4 and in the 1 shown. The characteristics of the fibers used in the test series are shown in Table 6.

In the test series (A) both two different rayon-viscose qualities (R1 and R2) where one was cellulose xanthate based and the other was a fiber regenerated from a NMMO solution as well as a purified cotton fiber (PV, structure CI) for the bondline. When bonding, three different polypropylene fiber grades (PP-5, -1 and -8) were used, of which PP-5 was a conventional homogeneous polypropylene fiber and the others were skin-core type (PP-8 a peripherally highly oxidized fiber). The results include, besides the fiber blends, also the bonding results for the pure components of the polypropylene fiber. The proportion of the binding fiber in the mixtures was 50% by weight.

When conventional polypropylene fiber is used, the bond strengths for the fiber blends of both rayon fibers are substantially of the same order of magnitude on either side of the T _m temperatures. The activation energies for the attachment methods are of the same order of magnitude at temperatures below T _m and quite close to the activation energy of binding the pure component of the polypropylene fiber. In the high temperature region, the activation energy for bonding to the rayon fiber blends substantially drops below the activation energy for polypropylene bonding, indicating at the same time that the cellulose fibers are participating in the bonding process. For fiber blends corresponding to PP-1 skin core type polypropylene fibers, the activation energies for bonding in the temperature range T <T _m for cellulose fiber blends (R1, R3 and PV) are of the same order of magnitude and close to the activation energy for binding the PP-1 -Component. The bond strengths for the blends are also close to each other. The temperature (T _m ), which corresponds to the maximum bond strength value for rayon-cellulose mixtures, increases substantially above the temperature corresponding to the binding fiber, with the cotton blend behaving in a reversed manner. In the high temperature range, the activation energy for binding cellulose mixtures is below the activation energy for the corresponding binding fiber, which shows, with the equation constants, that the cellulose participates in the binding process. The bond strength ratios [(R1 + PP) / PP] for the respective polypropylene fibers were:
PP-5: S = 8.16 × 10 ⁵ × exp [-12000 / RT]
PP-1: S = 4.81 × 10 ² × exp [-6060 / RT]
PP-8: S = 0.453

at a temperature of 162 ° C are the circumstances, which is available from the equations are: 0.375 / PP-5, 0.434 / PP-1 and 0.453 / PP-8, this order also the quantitative order of involvement in cellulose binding (at low temperatures, the order is approximately the reverse).

The peripherally oxidized fiber quality (PP-8), in its melting and other properties, is well matched to the fiber qualities obtained with the process used in the FI Application No. 974169 (Sub Example 1.5, pp. 37-39).

It It can be observed that due to the small overall area of the Bindens, the small contact surface of the individual binding points and the short delay times while tying the way of point bonding used in the tests was used, a low final strength for both Reyon- as well as cellulose mixtures (contact surface: the cellulose PP surface melt is low: liability). However, the point-bonding tests show the mutual dependence between the main factors in binding, namely the own binding system of polypropylene fibers and the binding system of cellulose mixtures, both in terms of the location of the maximum values of bond strength as well as the activation energies.

A second test series (B) for Sub Example 3 was carried out using a pair of rolls formed of a cotton and a steel roll. The results of the test series are shown in Table 5 and in 2 specified. The fiber properties of the test series are given in Table 6. From the results of the test series (B), the results corresponding to the pure polypropylene components are lacking because when a cotton-steel roll system is used, the result of bonding a polypropylene nonwoven fabric is a polypropylene film. The temperatures of the test series (A) and (B) do not correspond to each other. When bonding, the temperature of the unheated cotton roller increases to a value of about 80 ± 5 ° C, and therefore the temperature of the steel roller is increased to about 25 ° C above the conventional temperatures for steel rollers to the amount of heat required for bonding in to bring the system. For the row (A), the temperature gradient between the rolls is about 5 ° C, but for the row (B) about 90 ° C. In the test series (B), both two rayon viscosities (R2 and R4), one of which was based on xanthate and the other one on NMMO solvent, and two qualities of polypropylene (PP-3 and PP-6), one of which was a skin Core type and the other (PP-6) was a conventional homogeneous fiber, used for the preparation of bonding mixtures. Both from the results of Table 5 and the 2 , It can be seen that in the low temperature range (T <T _m ) the bonding strengths for three mixtures are about the same order of magnitude, but for a mixture (R2 / PP-3) the bond strengths are appreciably higher than for the previous ones. When a skin-core type PP-3 polypropylene fiber is used in bonding, the low temperature region (T <T _m ) and the increase in strength continue to higher temperatures compared to a conventional homogeneous fiber.

When the cellulose is leached from the fabric with phosphoric acid, it can be observed that in the low temperature range, the dissolution does not appreciably affect the strength for the blended fabric R4 / PP-6 and R4 / PP-3, and thus the strength in them Attributable primarily to mutual bonding between the polypropylene fibers. In the fiber blend R2 / PP-3 fabric, dissolution of the cellulosic component substantially lowers the strength of the fabric in the bonding region at both low and high temperature, demonstrating that the cellulose participates in fiber bonding in addition to polypropylene. In the area of high bonding temperatures, the bonding result of the fiber mixture R4 / PP-4 also shows that the cellulose is involved in the binding. In the higher temperature range, the term of the activation energy of the bond equation for the mixture carries a negative sign, that is, the bond strength increases even above the T _m temperature. This effect disappears from the results after leaching with phosphoric acid.

One reason for the binding activity the cellulose component of the R4 / PP-3 blend is the cellulose IV structure, which in the WAXS analysis in the surface layer of the cellulose fiber R4 is clearly visible. It is also observed that when with one Cotton roller system is bound, the binding area pretty much is great and due to the plastic bonding, the polypropylene melt spreads easily around the fiber, both factors being theirs contribute to the strength of the final product.

Sub-example 4.

in the Sub-example 4. will improve and regulate the bond examined between cellulose fibers by means of corona treatment.

The Improvement of the adhesion between cellulose fibers is important, in particular if polyester, polyamide or the like Fibers which are inert with respect to cellulose, the binding ones Polymer Synthetic Fibers for a water-needled fiber-textile product with a rather high Base weight include. To prevent cellulose fuzz replace, Here, if necessary, both premixing of polyolefin microfiber with cellulose as well as a melt-wetting transcrystallization process for the cellulose-polyolefin contact used after the needling process. become. Here facilitates one Improvement also in cellulose-cellulose adhesion providing precontact in the cellulose-polyolefin mixture. The combined Method can be used advantageously in the production of absorbent and at the same time using mechanically strong nonwoven laminate fabric become.

at investigations concerning adhesion between cellulose fibers, a pilot plant scale corona apparatus was used (Sherman High Frequency Generator: 20 ± 5 kHz, D-2 kW). The investigations concerning the detachment of cellulose lint were performed using a Gelbo Flex (5000 ES; EDANA 22.0-96: linting tendency).

In this regard, the adhesion between cellulosic fibers in a conventional spunbond fabric of polyester pulp cellulosic fiber (50 weight percent PES; 70 g / m ² ) was examined by hydroentangling the cellulose fiber sheet against a polyester nonwoven fabric on a wire net. The degree of mixing between the components was high in the product, but the delamination of cellulose lint was different on both sides of the fabric (pages A and B). For the basic comparison series, the initial fabric was treated only with the SHFG apparatus as a function of effect. The particle counts (N, number) / ft ³ ) in the cellulose lint that detached from the fabric increased slightly as a function of the electrical work (W, wh / m ² ) applied to the fabric, ie, N ( A) = 1010 + 143 W and N (B) = 3635 + 98 W.

To demonstrate the effect of the corona treatment, the amount of lint removed from the initial fabric was increased by wetting the fabric with saturated water vapor and drying it by thermal rollers (115 ° C, 0.1 to 40 kN / m). The results showed that the amounts of fuzz that detached from the test tissue were approximately linear as a function of electrical Work that was applied to it decreased. The following values were obtained for the lint quantities
N (A) = 37867 - (4183 - 5748) W and N (B) = 20328 - (1857 - 2713) W,
where the values for the 'work coefficient' in brackets correspond to the maximum and minimum values obtained. Lint values for the initial fabrics smaller than those examined above behaved accordingly when treated in the manner mentioned above.

According to the test results can the cellulose-cellulose fiber adhesion by means of a corona, Wetting and drying treatment can be improved very effectively, and already with a low electrical workload on the textile product is applied, the amount of fine cellulose lint, the detached from the textile product, practically reduced to zero.

The size distribution the cellulose lint that is emitted from the test fabric, proved to be virtually unchanged and also independent of lint, if lint of minimum size d = 0.5 μm five minutes were treated long. However, the lint size distributions proved which were regarded as exact mean values in the test series, as quite substantially different from the cumulative distribution, where the difference in percentage as a function of increased particle size decreased. If the particle size in the range from 0.3 to 0.5 μm was, the difference of the percentage proved to be a function time as the opposite in terms of the other particle size classes, what the special importance of lint classes below 0.5 microns in the system the distribution shows. It is especially observed that at no broadening of the lint classes of corona-treated tissues the percentage of the above type in different size classes as a function of the test duration appeared (which itself the effect the treatment also shows the lint size distribution).

If the liability results are assessed, it is observed that the amount of lint a clear function of the mechanical bending and Shear work that is applied to the fabric (in further processing, etc.), which is why the actual Result of linting is not the same as the test result. Similarly, the decrease in the degree of crystallinity of the cellulose and the Values of surface energy of it, which is caused by the electric work, into consideration wetting and transcrystallization of the polyolefin-cellulose contact if the corresponding sub-procedure in addition to Corona treatment process is used.

The result of the test series shows the absolute effectiveness of the corona setting pressure drying process and its wide range of regulation and applications.

bibliography

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Claims (12)

A method for improving and regulating the adhesion between cellulose fibers or cellulose-synthetic fiber blends, in particular polyolefin fiber blends, in a process for the production of nonwoven products, the process employing hydroentanglement and / or thermal bonding processes to form nonwovens from formats and / or gauzes To connect fibers and / or fiber mixtures, characterized in that a. the cellulose fiber is heat treated in a polar, non-cellulose liquid at elevated temperature, b. the molecular chain length in the surface layer of a synthetic fiber used to bind the cellulose is reduced by subjecting the fiber surface to a controllable oxidative chain degradation during the fiber spinning step in the molten state, c. a non-woven or nonwoven fabric of fibers or mixtures thereof, which in accordance with the preceding points a. and / or b. were treated using a thermal bond and / or hydroentanglement process, i. increasing the number of cellulosic / synthetic fiber contacts and, at the same time, preventing the detachment of short cellulosic fibers from the surfaces of the nonwoven laminates and blends by applying corona sputtering and drying treatment under pressure to the resulting fabric. Method according to claim 1, characterized in that that the polar liquid an organic liquid is that contains OH groups, especially water in equilibrium with its saturated Steam, at a temperature in the range of 100 to 250 ° C. Method according to claim 1, characterized in that that the cellulosic material is heat treated in the polar liquid such that the degree of crystallinity of at least the surface layer of the cellulose fiber material product corresponds to the degree of crystallinity of naturally Cellulose of 60 to 75% corresponds. Method according to claim 1, characterized in that that the cellulose fiber material in the polar liquid heat treated will, so the long identity distance value of at least the surface layer of the cellulosic material is at least 50 Å. Method according to claim 1, characterized in that that at the surface layer the polyolefin fiber used as the synthetic fiber, the degree of molecular chain degradation corresponds to an average degree of polymerisation of the product of 1000, i.e. For Polypropylene having an average molecular weight of about 42,000. A method according to claim 1, characterized in that the weight-average molecular weight of the polyolefin used as the synthetic fiber is reduced by means of the oxidation in spinning in the molten state to a value at which the viscosity of the polymer at a temperature of 170 ° C in the range of 1300 -5 Pa · s, the shear rate being less than 1 s ^-1 . A method according to claim 1, characterized in that the melting point of the surface layer of the polyolefin fiber used as a synthetic fiber corresponds to an average degree of polymerization of 1,000 as obtained by molecular chain degradation caused by oxidation in spinning. A method according to claim 1, characterized in that the surface energy of the surface layer of the polyolefin fiber used as the synthesis fiber corresponds to the number average molecular weight resulting from an average degree of polymerization and dispersion values of 1000 and 3-8, respectively, due to molecular chain degradation caused by oxidation in spinning However, the surface energy values are always below 20 mJ / m ² at a temperature of 170 ° C. Method according to claim 1, characterized in that that a. thermally bonded fiber mixtures in addition to a binding polyolefin fiber rayon viscose, cotton, long natural cellulose fiber, Pulp fiber as a cellulose fiber or as a cellulose mixture, b. Fiber blends or laminates that are hydroentangled should, in addition to a binding synthetic fiber, in particular a polyester, Amide and / or polyolefin fiber, a short pulp fiber alone or together with a short one Polyolefin stack or microfiber, a rayon fiber alone or together with pulp cellulose fibers and polyolefin fibers. A method according to claim 1, characterized in that after bonding both surfaces of the nonwoven product are subjected to an electrical work at a thickness of 2-12 Wh / m ² by means of a corona oxidation apparatus at a frequency of at least 20 ± 5 kHz. Method according to claim 1, characterized in that that after bonding both surfaces of the dry nonwoven product after corona treatment and processing with saturated Water vapor at a temperature of 100 to 110 ° C are wetted. Method according to claim 1, characterized in that that after corona treatment and wetting with water vapor the nonwoven fabric at a temperature in the range of 100 to 160 ° C using the load of a linear pressure of 0.1 to 40 kN / m is dried.