CH643886A5 - Cellulose-containing fibres - Google Patents

Description

The present invention relates to cellulose-containing fibers which are impregnated, preferably with the aid of a vacuum and / or pressure impregnation process, with at least one wood preservative in the fiber structure. Such cellulose-containing fibers have new properties and new fields of application.

The cellulosic fibers of the present invention are sulfate pulp fibers, sulfite pulp fibers, semi-chemical pulp fibers, chemomechanical pulp fibers, thermomechanical pulp fibers and mechanical pulp fibers, e.g. made of softwood or hardwood, straw or bark. The pulp can be bleached or unbleached. The pulp fibers can be in the form of separate fibers (wet or dry), sheets, rolls, granules, bales or the like. Important cellulosic fibers of the present invention are waste fibers, e.g. Waste paper or waste cardboard. However, it is also within the scope of the present invention that the cellulose-containing fibers are fiber bundles, sawdust, wood chips, chips, wood wool or synthetic cellulose fibers.

"Semi-chemical pulp fibers" are pulp fibers obtained by soaking wood chips by cooking with chemicals, followed by a relatively gentle treatment in a wood grinder.

“Chemomechanical pulp fibers” are pulp fibers obtained by treating wood chips in a wood grinder, together with chemicals, usually sodium bisulfite.

“Thermomechanical pulp fibers” are pulp fibers obtained by treating wood chips in a wood grinder while heating them with steam.

"Mechanical pulp fibers" are pulp fibers obtained by defibrating wood chips in a wood grinder, together with water or by pressing wood against a rotating grindstone under water treatment.

The cellulosic fibers of the invention are characterized by being impregnated with a metal oxide acylate.

The impregnation for the production of the fibers according to the present invention can be carried out according to known methods, e.g. by spraying, rolling, dipping, squeezing, etc., but the preferred method of impregnation is vacuum and / or pressure impregnation, e.g. Impregnation by pressure, in which the impregnating agent is introduced into the material by applying external pressure, or vacuum impregnation, in which the fibers to be impregnated are first subjected to a vacuum, whereupon the impregnating agent is introduced into the material by releasing the vacuum and, if appropriate, applying excess pressure becomes. It is also possible to use alternating pressure-vacuum stages to "pump" the impregnating agent through the material.

Depending on the solubility characteristics of the impregnating agent, the impregnation can also be carried out by using the method according to the Danish patent application no. 3020/75, i.e. the impregnation is carried out using an impregnating agent dissolved in a volatile solvent at a temperature immediately below the boiling point of the solvent. The solvent can e.g. Methylene chloride, ethylene trichloride, 1,1,1-trichloroethane, fluorotrichloromethane or the like. The impregnation according to this method has the advantage that the solvent can be easily and quickly removed from the impregnated cellulose-containing fibers, thereby eliminating the risk of fire when using conventional high-boiling combustible solvents.

The impregnating agents used according to the invention

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can be those e.g. for the preservation of wood against biological decomposition, for imparting fire resistance, for reducing moisture content fluctuations, etc. The impregnating agents used according to the invention, which can be used either alone or together with other known wood preservatives, e.g. Biocidally active metal compounds, which have proven their worth, are the so-called “metal oxide acylates”,

which represent a class of compounds Jacobus Rinse were invented and e.g. in Belgian patent no. 555 969, in Dutch patent no. 104261, in U.S. Patents No.3087949, No.3243447, No. 3 177 238, No. 3 518 287, No. 3 625 934, No. 3 546262, No. 3 634 674 and No. 3,673,229, in Belgian Patent No. 735 548 and in British Patents No. I 230412 and No. 1,274,718. It is believed that the metal oxide acylates are capable of chemically reacting with the hydroxyl groups of the cellulosic fibers by binding a metal acylate group via an oxygen bridge. Metal oxide acylates can be made from a variety of metals, and it is also possible to produce metal oxide acylates that contain more than one metal in the molecule. Metalloxidacylate can therefore (miniumoxidacylate aluminum as Aluminiumoxidtallat or Alumi-niumo.xidstearat or Titanoxidacylate as Titanoxidversat and Siliziumoxidacylate) for present purposes as water repellents, biocide Metalloxidacylate as Kupferoxidacylate and Zinkoxidacylate, and fire retardant Metalloxidacylate as Antimonoxidacylate, "made to measure " getting produced. Other interesting metal oxide acylates for the present purposes are oxide acylates of chromium, iron, manganese and zircon.

The metal oxide acylates are generally soluble in organic solvents and can be composed for impregnation accordingly and in accordance with the methods mentioned above.

The impregnating agents which are used according to the present invention are preferably selected such that they are fixed in the fiber structure in a practically water-insoluble manner, if necessary by combination with another agent for improving the fixing.

The main object of the present invention is the procurement of fibers which can be used as a replacement for inorganic fibers in various types of products, and in particular an object of the present invention is the procurement of cellulose-containing fibers which are used as a substitute for asbestos in products which are commonly used Contain asbestos such as asbestos cement products and brake pads, packings, seals, seals and washers can be used. However, the impregnated cellulosic fibers of the present invention can also be used for a wide range of other applications in which their modified and improved properties are desired.

One of the most important desirable properties of the modified cellulosic fibers of the present invention is increased dimensional stability, i.e. minimizing the tendency of cellulosic fibers to swell under the influence of water. For some purposes in which the cellulosic fibers of the present invention are to replace asbestos, it is also desirable that they have a high degree of resistance to degradation, which means that the cellulosic fibers of the present invention should be sufficiently impregnated against biodegradation.

An important feature in connection with the present invention is that the impregnation with suitable wood preservatives gives the cellulosic fibers improved properties with regard to their incorporation into a matrix which contains an inorganic binder such as cement. This is particularly believed for impregnants that are capable of reducing the inherent ability of cellulosic fibers to adhere to each other through hydrogen bonding, meaning that an effective test to determine the suitability of a wood preservative for treating cellulosic fibers for the present purposes is a sheet to form from the impregnated cellulose fibers, to dry the sheet and to determine the thickness of the sheet. The less bond between the impregnated cellulosic fibers in the resulting sheet, the more inert the impregnated fiber, and is believed to be more suitable for incorporation into inorganic binder matrices and other purposes in which the fiber contains inorganic fibers such as asbestos to replace.

An advantage of the impregnated fibers of the present invention is that they replace asbestos in existing asbestos cement producing machines such as e.g. Hatschek / Magnani machines can be used, but the impregnated fibers according to the invention in the form of pulp fibers can also be used e.g. are incorporated into webs which are produced on paper machines.

One possible application of the cellulosic fibers according to the invention is therefore their use as partially or completely inert fibers in the process described in Canadian Patent No. 1 113 661, ie the fiber of the present invention can be used in whole or in part to replace the mineral fibers which are used in some of the compositions described in the aforementioned patent applications. For example, The fibers according to the invention, which are impregnated with wood-preserving heavy metal compounds, are used partly or completely to replace the mineral fibers in the back of the carpet or floor covering, which are described in the patent applications mentioned above. Other composite materials, in which mineral fibers can be replaced in whole or in part by the fibers according to the invention, are cover felts, wallpapers, laminated panels, brake pads and other composite materials of the type described in the patent applications mentioned above, and for similar composite materials produced by other methods , including drying methods.

The impregnated fibers according to the invention can also be used as a replacement for glass fibers as reinforcements in composite materials with an organic binder matrix, such as polyester and epoxy polyester. In this case, a web or nonwoven is made from the impregnated fibers by a dry or wet method using a suitable binder, analogous to the production of woven or nonwoven products from glass fibers.

The invention further relates to a method for producing the impregnated cellulose-containing fibers, which method is characterized in that cellulose-containing fibers are impregnated with a metal oxide acylate in a vacuum and / or pressure impregnation method. As mentioned above, this method can be carried out in a manner known per se in connection with wood preservation. The cellulosic fibers can be in any desired shape, e.g. as granules, sheets, rolls, bales or, if the fibers to be impregnated are waste fibers, simply impregnated in the form of paper waste or cardboard waste. If the impregnation takes place in the same factory in which the

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impregnated fibers continue to be used in a wet process, the defibrillation can take place immediately after the impregnation and without a drying step in between. The impregnation technique can also be combined with the production of paper pulp of any kind, in which case e.g. the impregnation can be carried out in one step after the pulp has been taken up on the sieve, but before drying. In this case, one equivalent of vacuum / pressure treatment can be obtained by pressing the web to a low water content before passing it through the impregnation bath. However, the impregnation can also be carried out in connection with papermaking by impregnating a roll of the dried pulp in one of the ways described above.

Another method for impregnating cellulose fibers, in particular in connection with the wet production of composite materials, is to carry out the impregnation in situ with the aid of an oil emulsion which has an affinity for the cellulose fibers and in which the impregnating agent is dissolved in the oil. For example, in the manufacture of cementitious composite material in which cellulosic fibers are used as a replacement for asbestos or other fibers dispersed in water, an oil emulsion of the type mentioned above is added to the fiber suspension before the cement is added.

The amount of impregnating agent in the impregnated fibers of the present invention is usually at least one percent by weight, calculated on the dry fiber weight and usually at least five percent by weight and often seven to ten percent by weight.

When the fibers are incorporated into a composite containing cement as a binder, the cement content of the composite is usually 25 to 99 percent by weight, e.g. 50 to 90 percent by weight, and often 80 to 90 percent by weight, and the amount of impregnated cellulose fibers can typically be 1 to 75 percent by weight, especially 5 to 50 percent by weight, and often 10 to 20 percent by weight of the composite. The composite may contain, in addition to a cement binder, other inorganic materials such as puzzolan, e.g. in an amount of 2 to 20 percent by weight, calculated on the weight of the cement, fly ash, etc.

Other composite materials with an inorganic binder that can be made using the impregnated fibers of the present invention are materials in which the binder is calcium silicate or gypsum, and the amounts of these inorganic binders and impregnated fibers may be the same as those related to above cement-bonded composite materials mentioned.

Composite materials which contain the impregnated fibers according to the invention can also contain both an inorganic binder and an organic binder. Particularly suitable organic binders for this purpose are polymeric materials, consisting of solid individual particles or fibers, which have polymers at least on their surfaces, the polymer being a water-insoluble, solid synthetic polymer which forms a film when heated, in particular such polymer materials, which are mentioned in detail in the above-mentioned patent applications. The amount of such polymers in composite materials, which also contain inorganic binders, is usually 1 to 30 percent by weight, calculated on the total weight of the composite material.

According to the above, a method for producing a composite material using the impregnated fibers of the present invention may include incorporating the impregnated cellulosic fiber material dispersed in water, and if this method is used for producing a composite material containing an organic binder such as e.g. Cement, the effective retention and flocculation of the system according to the present invention is obtained by using a polyelectrolyte according to the principles described in the patent applications mentioned above. The polyelectrolyte is preferably of the neutral or cationic type. An object of the present invention is therefore a composite material which contains impregnated cellulose-containing fibers according to claim 1 and additionally contains a polyelectrolyte; a polyelectrolyte can also be a useful flocculant in composite materials of the present invention which serves as an organic binder, see the description in the above-mentioned patent applications.

When a film-forming polymer, when heated, is incorporated into the composite material which also contains an inorganic binder, a suitable method for producing such composite materials is to treat the resulting material after shaping it into the desired shape to activate the film-forming properties of the polymer undergo. The treatment for activating the film-forming properties of the polymer can be carried out after the inorganic binder has hardened, or this treatment of the polymer can be carried out before the inorganic binder has hardened, and subsequent to this treatment, the amount of water required for the hardening of the inorganic binder can be added whereupon the final hardening can be carried out. Another possibility is to combine the hardening of the inorganic binder and the activation of the film-forming properties of the polymer in one treatment, e.g. in an auto-claven, depending on the binder and polymer used.

If the composites are made using impregnated fibers according to the present invention and with an inorganic binder by a wet method, another way to achieve an improved dispersion of the impregnated fibers is to use an oil as a dispersing aid, optionally combined with the use of a polyelectrolyte . The oil can advantageously be a non-drying oil which can be added to the fibers in the form of an emulsion.

The impregnated cellulosic fibrous material of the present invention can be defined by conventional methods, e.g. by wet defibrating in a pulper or by dry defibrating.

As used herein, the term "hydrophobing agent" means not only agents that impart true hydrophobicity to the treated fibers, but also agents that change the properties of the fibers in the direction of hydrophilicity to hydrophobicity.

In the present text, the term “cement” means both Portland cement types and other inorganic cement types.

Example /

Strips of filter material made from bleached sulfate cellulose were immersed in a solution of seven parts by weight of "Frigen Sil" (fluorotrichloromethane) and one part by weight of metal oxyacylate containing 30% white spirit for one second. The strips were placed in an oven at 100 ° C for one hour

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dried. The metal oxide acylates used were titanium oxide stearate (D-14-00), zinc oxide versat (E-12-80, which contained only 20% white spirit), aluminum oxide phthalate (C-10-70), aluminum oxide stearate (C-14-70) and Alumina stearate / phthalate (C-10 / 14-70), all supplied by MOACO SA, Echallens, Switzerland. The impregnated paper strips, with the exception of the strips treated with zinc oxide, showed hydrophobicity, in particular the sample which had been treated with titanium oxide stearate, and all impregnated paper strips, including the strip treated with zinc oxide, showed less elonation after immersion in water than the control.

The strips were defibrated by beating them in the water in a mixer. The strip treated with zinc oxide was defibrated as easily as untreated strips, while approximately 50% longer treatment times were required to defibrate the remaining strips treated with metal oxide acylate. After defibrillation, the alumina phthalate-treated fibers were sheeted in a laboratory sheet former and the sheet was dried in an oven at 100 ° C for one hour. The dried sheet obtained had significantly less strength than a corresponding sheet made from untreated fibers, which suggests little or no chemical bonding between the fibers.

Example 2

A sheet of “Boliden K 33” impregnated fibers, which had been produced in a laboratory sheet former and then dried, was dissolved in a solution of one part of titanium oxide stearate (D-14-00 from MOACO SA) in seven parts of “Frigen S 11 »immersed for a second. The mass was then dried in an oven at 100 ° C. for one hour. After drying, the material showed excellent hydrophobic properties, in contrast to fibers impregnated with the «Boliden K 33», which had not been treated with titanium oxide stearate.

Example 3

10 g of filter paper which had been treated with aluminum oxide stearate (C-14-70) as described in Example 1, 250 g of cement (Super Rapid, 4500 Blaine) and 900 ml of water were mixed in a mixer for 6 minutes. The suspension obtained was divided into 9 portions, which were successively filtered on a laboratory sheet maker to form a nine-layer cement disc. The excess water was then pressed out of the cement disc at a pressure of 15 kp / cm 2. After two days of hardening in a plastic bag (to prevent water evaporation), the pane was air dried at room temperature. The disk obtained had a smooth surface io and an even fiber distribution. It had good flexural strength and the fracture surfaces also showed a homogeneous distribution of the fibers under the microscope.

A cement disc produced as above, but using untreated sulfate cellulose pulp fibers, had a very uneven and lumpy fiber distribution both on the surface and on the fracture surfaces. The cement particles also tended to separate from the fibers and form a low-fiber sediment.

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Example 4

Cement disks were made as in Example 3, but using one with titanium oxide stearate (D-14-00) or zinc oxide versat (E-12-80), aluminum oxide phosphalate 25 (C-10-70) and aluminum oxide stearate / phthalate (C-10 / 14-70) impregnated filter paper. All of the disks obtained had good flexural strength and both their surfaces and the fracture surfaces showed an even and homogeneous fiber distribution.

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Example 5

10 g of filter paper impregnated with metal oxide acylate, 220 g of cement (Super Rapid, 4500 Blaine) and 2700 ml of water were mixed in a mixer for 6 minutes. The 35 types of paper used were impregnated with the same metal oxide acylates as in Example 3 and Example 4, 0.04%, calculated on the weight of the drying agents, of "Prodefioc Cl", a polyelectrolytic flocculant, were added. The suspension was filtered on the laboratory sheet 40 production device and processed as in Example 3. The surfaces of the cement disks obtained showed a uniform and homogeneous fiber distribution, which could also be observed under the microscope on the fracture surfaces.

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Claims (16)

643886 2nd PATENT CLAIMS 1. Cellulose-containing fibers, which are sulfate-pulp fibers, sulfite-pulp fibers, semi-chemical pulp fibers, chemo-mechanical pulp fibers, thermomechanical pulp fibers or mechanical pulp fibers or waste paper or waste cardboard fibers or fiber bundles, sawdust, wood chips, wood wool or at least synthetic cellulose fibers are characterized by this are impregnated with a metal oxide acylate. 2. Fibers according to claim 1 in the form of separate fibers in the dry or wet state or in the form of sheets, rolls, bales or granules. 3. Fibers according to claim 1 or 2, characterized in that the metal oxyacylate is a hydrophobizing metal oxyacylate such as an aluminum oxide acylate or a titanium oxide acylate. 4. Fibers according to claim 1 or 2, characterized in that the metal oxide acylate is a biocidal active metal oxide acylate such as a zinc oxide acylate. 5. Fibers according to claim 1 or 2, characterized in that they are impregnated both with a biocidally active heavy metal compound and with a hydrophobic and / or fire-retardant metal oxide acylate. 6. A method for producing fibers according to claim 1, characterized in that cellulose-containing fibers, which sulfate pulp fibers, sulfite pulp fibers, semichemic pulp fibers, chemomechanical pulp fibers, thermomechanical pulp fibers or mechanical pulp fibers or waste paper or waste cardboard fibers or fiber bundles, sawdust, Wood chips, wood wool or synthetic cellulose fibers are to be impregnated with a metal oxide acylate in a vacuum and / or pressure impregnation process. 7. The method according to claim 6, characterized in that the impregnation comprises first an evacuation step, followed by applying the impregnating agent at normal pressure or positive pressure. 8. The method according to claim 6, characterized in that the metal oxyacylate is applied dissolved in a low-boiling organic solvent at a temperature immediately below the boiling point of the solvent. 9. The method according to claim 6, characterized in that the cellulose fibers are in the form of sheets, rolls or bales, which are defibrated immediately after impregnation. 10. Use of cellulose-containing fibers according to claim 1 for the production of composite materials. 11. Use according to claim 10, characterized in that the binder is an organic polymer. 12. Use according to claim 10, characterized in that the binder is an inorganic binder. 13. Use according to claim 10, characterized in that the binder is a combination of an inorganic and an organic binder. 14. Use according to claim 10 for the production of a composite material which contains a polyelectrolyte. 15. Composite material obtained by use according to claim 10. 16. The composite material according to claim 15, obtained according to one of the claims 11 to 14.