FI112962B - A paper machine fabric - Google Patents

Description

! 112962

A paper machine fabric

Background of the Invention

The present invention relates to a papermaking machine fabric made of at least partially fibrous and / or filamentary structures.

Paper machine fabrics, such as wires and blankets, are known to be used in various types of abrasive web-like machines, such as paper machines, tissue machines, board machines and the like, hereinafter referred to as paper machine.

Nowadays, papermaking machine fabrics are mostly made of polymeric materials but are also known as papermaking machine fabrics made of metal such as bronze. The tissues are formed mainly by weaving or knitting or by the so-called non-woven structures.

The problem with papermaking machine tissues is that they attach specifically to bacteria and fungi, but also to viruses, yeasts, molds, algae, and other similar microorganisms that enter the process equipment with or without the pulp or water used in the process. The paper machine provides microorganisms with a favorable growth environment with suitable and stable humidity and temperature. As a result, these microorganisms rapidly grow their populations, resulting in the formation of mucus on paper machine tissues and other surfaces of paper machines. In particular, mucus impairs the function of papermaking machine fabrics because, for example, the tissue water permeability is reduced. Mucus often interferes with the operation of other parts of the system and may, inter alia, cause corrosion. In addition, microorganisms may cause stains and odors, degradation or other / * 25 deterioration of the fiber raw material and additives in the fiber product to be manufactured. Therefore, the equipment must be regularly cleaned with microorganisms: causes downtime for production, and thus a wide variety and considerable costs.

; : There is a clear trend in papermaking technology to introduce closed loops and use deinked pulps as the raw material for fiber. As a result, the problems caused by micro-organisms have become more common and worsened. A known solution to the above problem area is to add to the process water slimicides which inhibit or at least retard the growth of strains of microorganisms. The control of mucus requires the use of large quantities of mucilage control agents, which by themselves or some of the 35 end products derived from them may be harmful to the personnel handling them or which. . can cause problems when in the wild. For example, toxic fungal growths have been observed in the pulp of paper mills 2 112962. Therefore, waste masses cannot be destroyed except by first treating them with costly processes. In addition, the transition to neutral or alkaline papermaking has limited the use of conventional mucilage agents: on the other hand, the above-mentioned processes provide particularly favorable conditions for microorganisms to live and reproduce.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a novel and improved papermaking machine fabric that reduces mucus formation in a papermaking machine.

The papermaker's tissue according to the invention is characterized in that the papermaker's tissue is provided with a substantial amount of antimicrobial agent which reduces mucus formation in the papermaking machine.

By incorporating an antimicrobial agent in a papermaking machine fabric, the advantage can be achieved that the amount of microorganisms present in the papermaking machine can be reduced or even completely prevented from forming certain strains of the microorganism, thereby reducing or preventing clogging of the papermaking tissues. Further, the use of known slime control agents in process waters can be reduced. Even fewer disruptions of the paper machine due to microorganisms are caused.

Preferably, the papermaking machine fabric comprises fibers of polymeric material in which the antimicrobial agent is doped with the polymeric material and from which it is gradually diffused onto the fiber surface, whereby the antimicrobial activity | ·! lasts throughout the life of the paper machine fabric in question.

DETAILED DESCRIPTION OF THE INVENTION • · *: 25 In paper machines such as flat wire machines, composite machines, cylindrical ·, '; wire machines, tissue machines, board machines, double wire machines, and. in others, the papermaker's fabrics typical of that particular machine type are used. Paper machine fabrics are mainly wet-end fabrics, press section press felts, dryer section dryer fabrics and felts, and shoe-braid webbing belts, or parts thereof, but other paper machine fabrics are known.

Paper machine fabrics are structures known per se and are not discussed in detail in this application. However, it should be noted that; . . wires used at the wet end of a papermaking machine to remove water from the pulp;. 35 typically to about 20% solids. These wires are either only I · 3 112962 on one side or both sides of the pulp web. Depending on the structure of the press, the press section of the papermaking machine uses a press felt on one or both sides of the web to be penetrated by the water in the web during the pressing step. The purpose of the press felt is to carry the water after pu-5 pressing without letting it move back into the web. The dry matter content of the web leaving the press member is typically about 35-45%. The dryer section of the papermaking machine utilizes dryer fabrics or blankets to guide the paper web to be dried through the dryer section. In the drying section, the web is dried to balance the humidity of the ambient air.

10 The materials and structure of paper machine fabrics vary, depending on the function of the fabric and the type of paper machine. Their material is mainly made of a synthetic polymeric material or alloy, but paper machine fabrics made of natural polymers or metals such as bronze are also known. Materials included in said groups of materials may also be combined into the same paper machine fabric. Among the polymeric materials used, for example, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamide (PA), polyphenylene sulphide (PPS), polyaryl ether ketones (PEEK), polydimethylene cyclohexylene (butane) butadiene (PC), but also (but not limited to). The material of the papermaker's fabric is typically in fibrous or filamentous form, but the papermaker's fabric may also include structural parts made of, for example, membrane and / or foamed material. Paper machine fabrics are mainly formed by weaving or needle stick, in addition, non-woven and non-woven blankets are also known.

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'· 25 It should also be noted that the papermaker's fabric can be one or more layers.

The paper machine fabric of the invention comprises an antimicrobial agent. As used herein, an antimicrobial agent is a compound that inhibits the development, spread, formation or other similar phenomenon of the life of a microorganism. The mechanism of action of the anti-30 microbial agent is based either on its own effect or, when physically or chemically reacted, to produce the desired effect.

The antimicrobial agent, or precursor thereof, may be provided in a paper machine-forming material without carrier, or may first be incorporated into a suitable carrier such as a coating agent, polymer, ceramic or other similar matrix with which it is incorporated into the tissue-forming material. In a preferred embodiment, the antimicrobial agent is applied to a film-like or foamed material, with which it is introduced into a papermaking machine tissue.

As used herein, the term microorganism refers to viruses, bacteria, protozoa, molds and other fungi, yeasts, algae, or other undesirable organisms in the paper machine.

The antimicrobial agent can be arranged in a variety of ways in papermaking machine tissue. This may include, but is not limited to, the method principles discussed in "Textiles Having the Ability to Deliver Reactive 10 Chemical Systems" by R. Broughton, L. Slaten, G. Mills, D. Worley, C. Sunderman, S. Michielsen, Gang Sun; National Textile Center Annual Report: November 2000, C98-A17. The following are some principles by which an antimicrobial agent may be arranged in a papermaking machine fabric: 1. Add a reactive antimicrobial agent to the surface of the reactive fiber or yarn, or, if the fiber or yarn to be treated is inactive, first creating reactive sites For example, polyamide 66 may be treated with 2,2,5,5-tetramethylimidazolidin-4-one (2,2,5,5-tetramethylimidazolin-4-one) by pretreatment with formaldehyde solution. Another example is the activation of an inert polyamide fiber or yarn by attaching to its surface a catalyst which converts a portion of the surface of the fiber or yarn to polyacrylic acid. Protoporphyrin IX (proto- ·· *, Porphyrin IX) is grafted at these sites. Protoporphyrin IX converts atmospheric oxygen microbes into a toxic antimicrobial agent.

• «25 2. Activate the surface of the monomers by, for example, adding reactive components or applying strong photochemical or thermochemical energy to it. The monomers are then polymerized or the small compounds are simply reacted with each other to form the polymer. The polymer is treated with an antimicrobial agent which adheres to the activated surface. The resulting polymer is further used in the production of polymeric fibers for the manufacture of paper machine fibers or yarns; in the manufacture of material.

3. Physically apply an antimicrobial agent to the fiber or wire · ion surface. For example, halamines, such as cyclic N- '35 halamine, or their precursors can be incorporated in this manner into the polymeric material.

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5 112962 surface. When in contact with certain microorganisms, halamines release antimicrobially active chlorine.

Arrangement of the N-halamine in the papermaking machine fabric can be accomplished by first attaching the precursor poly-1,3-dichloro-5-5 methyl-5- (4'-vinylphenyl) hydantoin (poly-1,3-dichloro-5-methyl) to the surface of the fabric -5- (4'-vinylphenyl) hydantoin). The precursor is then chlorinated to the N-halamine.

Other compounds that are similarly attached include hydantoin (hydantoin), triazine dione (triazine Dione), imidazolidinone (imidazolidinone) and pyrimidinone (pyrimidinone).

4. Copolymerize the antimicrobial with the polymer to form a copolymer. By doing so, the antimicrobial agent is present throughout the copolymer material, so that it does not wear out of the material and the duration of action lasts throughout the life of the papermachine fabric.

5. Encapsulate the antimicrobial agent in the polymer material along with the carrier. The carrier may be, for example, a ceramic material containing silver. The ceramic material gradually diffuses silver ions out of the polymeric material. Silver ions are antimicrobial against, among other things, certain bacteria and prevent their occurrence or growth in paper machine tissue. An example of this is the product known as Livefresh® 20, in which silver-containing ceramic particles are doped with a polyamide polymeric fiber. An advantage of the method is the long-term antimicrobial activity because the antimicrobial agent is gradually released over a long period of time.

6. Mix the antimicrobial agent with the polymeric material so that • ». forming a substantially homogeneous blend, and forming the resulting * * '· 25 blend into fabric machine-compatible components. For example, the N-halamines or their precursors already mentioned above can be dispersed in the polymeric fiber or the polymer forming it. If the dispersion process conditions! are suitable, the chlorination to the N-halamine is preferably carried out prior to dispersion since this results in a greater proportion of the precursor being chlorinated. If the pro-30 process conditions prevent the dispersion of the N-halamine, its precursor is dispersed and chlorination is carried out only after this dispersion. An advantage of the method is that the antimicrobial agent is released from the polymeric material over a long period of time.

Other anti-microbial agents that are incorporated into the polymeric material of the papermachine fabric include triclosan and 10,10 Oxybisphenoxarsin 35 (10,10-Oxybisphenoxarsin, OBPA), also known under the trade name: Permafresh®.

6 112962 7. By Absorption of Antimicrobial Material into Paper Machine Fabric Material by Dyeing Technique: Some antimicrobial compounds are very similar to dyes and can thus be attached to dye-dyeing materials. By way of example, quaternary ammonium compounds which have a positive charge and can thus attach to negatively charged sites on the fibers.

By providing the antimicrobial agent to the papermaking machine tissue, a substantial amount can be prevented or at least substantially reduced in the presence of the microorganisms in the papermaking tissue, other papermaking surfaces, and in process fluids. At the same time, the amount of algae pesticides known per se can be reduced or even eliminated. The substantial amount of antimicrobial agent depends on the microorganisms to be controlled, the conditions prevailing in the paper machine, and the desired purity level.

It will be obvious to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims. Thus, antimicrobial agents other than those described above, such as the metals and / or metal salts disclosed in EP-A-0 783 048 A2, can be applied to paper machine fabrics. The an-20 thimicrobial agent may also be an organosilane compound such as alkoxysilane, which is discussed, inter alia, in U.S. Patent No. 6,120,587. Other antibacterial agents known per se or unknown but emerging bacterial agents may be employed in the invention. One or more antibacterial agents can be used in papermaking tissue: for example, a combination of an alkoxysilane and a quaternary ammonium compound, such as 3-trimethoxysilylpropyldimethyloctadecylammonium chloride (3-trimethoxysilylpropyldimethyloctadecylammonium chloride), also known as Antimycanammonium chloride.

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Claims (12)

7, 112962 1. A papermaking machine fabric made at least partially of fibrous material! and / or filamentary structures, characterized in that a substantial amount of antimicrobial agent is present in the papermaking machine fabric which reduces the formation of glue in the papermaking machine. Paper machine fabric according to claim 1, characterized in that it is a wet end fabric. Paper machine fabric according to claim 1, characterized in that it is a press fabric. Paper machine fabric according to Claim 1, characterized in that it is a press felt. Paper machine fabric according to Claim 1, characterized in that it is a drying wire or felt. Paper machine fabric according to one of the preceding claims, characterized in that the fibrous and / or filamentary structures comprise a polymeric material. Paper machine fabric according to Claim 6, characterized in that the antimicrobial agent is doped with said polymeric material. Paper machine fabric according to claim 7, characterized in that the antimicrobial agent is doped with the carrier material in the polymeric material. Paper machine tissue according to any one of the preceding claims, characterized in that the antimicrobial agent comprises one or more of the following compounds: 2,2,5,5-tetramethylimidazolidin-4-one, halamine, hydantoin, triazine dione, imidazolidinone, pyrimidinone, triclosan, 10,10-oxybisphenoxarazine (OBPA), quaternary ammonium compound, organosilane compound, 3-trimethoxysilylpropyldimethyloctadecylammonium chloride. Paper machine fabric according to any one of the preceding claims, characterized in that the antimicrobial agent comprises metal and / or metal; : salt. A paper machine fabric according to any one of the preceding claims, characterized in that it comprises a film-like material and that the antimicrobial agent is adapted to said film-like material. i ·% • i · •. * · T · 112962 i Paper machine fabric according to one of the preceding claims, characterized in that it comprises a foamed material and that the anti-microbial agent is applied to said foamed material. i [* »f 112962