CH640026A5 - METHOD FOR PRODUCING A HIGH FILLING LEAF. - Google Patents

Description

The present invention relates to a method for producing a sheet with a high degree of filling. The sheets that can be produced according to the invention are, if appropriate, sheets containing pigmented, non-woven fibers, and are characterized by a high filler content and low fiber content.

So far, paper has been described as sheet material, which is made up of many small individual fibers, usually cellulose fibers, which are connected to one another. Small amounts of latex have previously been used in the paper making process. Fillers have also already been used to improve certain properties of the paper, even if this reduces the strength of the sheet. The amounts of fillers which have hitherto been used in the paper production processes by means of conventional devices, such as, for example, the Fourdrinier machine, have generally not been above 30 or 35% by weight of the total dry weight of the sheet, although up to 40% by weight. % are disclosed as processable. Retaining the filler in the sheet during sheet production has been a major problem.

The use of asbestos fibers in the manufacture of other types of fibrous sheets has been carried out for many years. Sheets containing such fibers have been used advantageously in the manufacture of products such as floor coverings and sound absorbing papers or sheets. However, asbestos fibers have been found to be dangerous to human health. The use of asbestos fibers has been banned in some countries and stringent restrictions on the use of asbestos are being considered in the United States. Accordingly, new systems that do not use asbestos fibers are highly desired. Such new asbestos-free systems can represent significant progress, although their properties do not show any significant advantages over the asbestos-containing materials. As soon as the properties or the manufacturing conditions are improved, such systems show great advantages.

It would be particularly advantageous if a novel process for the production of high filler paper and especially asbestos-free products could be carried out with existing equipment, which would make it unnecessary to make new capital investments.

The process according to the invention includes the combination of a water-dispersible fiber, a film-forming water-insoluble organic polymer and an inorganic filler, as a result of which a sheet which separates from water is formed.

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The process according to the invention for producing the sheet described above is characterized in that the following steps are carried out:

(I) preparation of an aqueous dispersion which contains 1-30% by weight, based on the total dry weight, of water-dispersible fibers,

(II) mixing this dispersion with:

(A) 60-95% by weight, based on the total dry weight of at least one finely divided, essentially water-insoluble, non-fibrous inorganic filler and

(B) 2 to 30% by weight, based on the total dry weight of a binder which contains at least one film-forming water-insoluble organic polymer material in the form of an ionically stabilized latex, which does not contain more than 0.7 milliequivalents of bound charge per gram of the polymer in the latex contains

(III) colloidally destabilizing the resulting mixture by mixing the product of steps (I) and (II) with a sufficient amount of a water-soluble or water-dispersible ionic material or a polymer having a charge that is equivalent to that of the ionic stabilization of the latex is opposed to the formation of a fibrous agglomerate in aqueous suspension,

(IV) distribution and dewatering of the aqueous suspension on a porous support to form a wet fleece, and

(V) drying the fleece, and the ionically stabilized latex lacking a non-ionic stabilization sufficient to impair the formation of a fiber agglomerate.

In stage I, the amount of water-dispersible fibers is preferably 5-15% by weight.

In stage II, in particular 75-90% by weight of the inorganic filler and 5-15% by weight of the organic polymer are used. The organic polymer in the latex contains no more than 0.7 milliequivalents of bound charge per gram of the polymer, preferably 0.03 to 0.4 milliequivalents per gram of polymer.

The process according to the invention is preferably carried out in such a way that the colloidal destabilization stage forms a fiber agglomerate in aqueous suspension, with the property that the suspension at a concentration of 100 g solids in 13500 ml over a period of 4 to 120 seconds in a 25.4 x 30.5 cm Williams standard foil mold with a 5.1 cm outlet and a 76.2 cm water pipe branch, which is provided with a 0.149 mm stainless steel sieve with a wire diameter of 0.0114 cm, dewatered in such a way that at least 85% of the total solids of the fiber agglomerate, which contain at least 60% of the fillers, remain in the moist tissue when dewatering according to stage (IV).

Significant advantages of the process according to the invention are that a product is obtained which has a low fiber content and a high proportion of inorganic filler material, and which product can be processed very easily on conventional paper-making equipment, and a further advantage of the process according to the invention in the good properties of the product. The preferred high filler fiber-bonded asbestos-free sheets that are separated from water are useful as a replacement or improved substitute for asbestos-containing sheets in many forms of use, but they are not limited only to these forms of use. Typical applications of such sheets are sound absorbing papers, muffler liners, exhaust pot linings, Unterlagsfilze for vinyl floor coverings, papers for sealing purposes, roofing felts, sound absorbing papers, schallschluk-kende papers tube envelopes, insulation paper, heat deflection papers, heat-reflecting papers, covering materials for cooling towers, electrical insulating papers , Papers with electrical resistance as well as substrates for printed circuits or printed circuit board products.

To carry out the process according to the invention, it is necessary that water-dispersible fibers, film-forming water-insoluble organic polymers and finely divided, essentially water-insoluble, non-fibrous inorganic fillers are available. A flocculant is also required in the preferred embodiment of the method.

The water dispersible fiber that is needed can be a natural or synthetic fiber or a mixture of such fibers. Water dispersibility is usually ensured by a small amount of ionic or hydrophilic groups or charges which are present in such an amount that water solubility is not achieved. Long or short fibers or mixtures thereof are applicable, but short fibers are preferred. Many fibers made from natural materials are anionic, such as wool pulp. Some synthetic fibers can be pretreated to make them slightly ionic, i.e. anionic or cationic. Glass fibers, glass powder, finely chopped glass, blown glass, recycled waste paper, cellulose from cotton and linen rags, mineral wool, synthetic wood pulp, such as is made from polyethylene, straws, ceramic fibers, nylon fibers, polyester fibers and similar materials are applicable. Particularly useful fibers are cellulose and lignin cellulose fibers, which are commonly known as wood pulp from various types of hardwood and softwood, such as ground wood (wood pulp), steam-heated mechanical pulp, chemomechanically produced pulp, semi-chemically produced pulp and chemically produced pulp. Typical examples are unbleached sulfite pulp, bleached sulfite pulp, unbleached sulfate pulp and bleached sulfate pulp.

The film-forming water-insoluble organic polymers which are particularly suitable for carrying out the process according to the invention are natural or synthetic polymers and can be homopolymers and copolymers of two or more ethylenically unsaturated monomers or a mixture of such polymers. In particular for the ease of carrying out the process according to the invention for the production of the product and for reducing the loss of waste materials to the environment, it is provided that the polymer is in the form of a latex, i.e. in the form of an aqueous colloidal dispersion. Typical examples of organic polymers are natural rubber, synthetic rubber such as styrene / butadiene rubber, isoprene rubber, butyl rubber and nitrile rubber and other rubbery or resinous polymers made from ethylenically unsaturated monomers which form films and preferably do so at room temperature or below, although in special cases a polymer can be used which is film-forming at the temperatures used in sheet production. Non-film-forming polymers can be used in mixtures, but it must be ensured that the mixture obtained in this way is film-forming. Polymers which become film-forming by adding plasticizers can also be used. Polymers that are readily available in latex form are preferred, and especially hydrophobic polymers that are made from one or more ethylenically unsaturated monomers by emulsion polymerization

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getting produced. Typical examples of such latex materials are described in U.S. Patent No. 3640922 to David P. Sheetz in columns 1, line 61 through column 2, line 34. Section (in particular column 2, lines 2-9) shows the advantage of latex materials made of polymers and copolymers, which contain essentially no proportion of hydrophilic groups. For use in the method according to the invention, the latex materials preferably contain some ionic hydrophilic groups, but it must be ensured that a non-ionic colloidal stabilization is not present to an adequate extent because this would interfere with the formation of the fibrous agglomerate. Such non-ionic colloidal stabilization can be ensured by non-ionic emulsifiers or by the presence of copolymerized monomers containing the types of hydrophilic groups present in non-ionic emulsifiers, such as hydroxyl groups and / or amide groups . Accordingly, when monomers containing such hydrophilic groups are polymerized as ingredients for making the latex polymer, such monomers are generally in small amounts, such as less than 10%, and usually less than about 5%, based on the polymer weight, for the best results. Although very small amounts of nonionic emulsifiers can be tolerated in some compositions, their use is generally not advantageous and they should not be present in amounts that can interfere with the destabilization step in the process of the invention.

The latex compositions which are suitable for use in the process according to the invention are selected in particular from latex types in which a polymer which corresponds to the above-mentioned characteristics is kept in aqueous dispersion by ionic stabilization. Such ionic stabilization can be obtained by using, for example, an ionic surfactant or small amounts of a monomer containing ionic groups in the emulsion polymerization to prepare the latex. The small amount of ionic groups associated with the polymer provides no more than 0.7 milliequivalents of charge per gram of the polymer in the latex. It is usually preferred that the latex component used in the process according to the invention contains a bound charge in the polymer of 0.03 to 0.4, and in particular between 0.09 and 0.18 milliequivalents per gram of polymer in the latex, it being particularly preferred that the charges are provided in the form of carboxylic acid salt groups. The term "bound to the polymer", which refers to the ionic groups or charges, refers to ionic groups or charges that are not desorbable from the polymer. Materials bearing such ionic groups or charges, as noted above, can be obtained by copolymerizing a monomer containing ionic groups and / or by other means, such as drip polymerization, of the compound (via covalent bonding) Catalyst fragment with the polymer, in particular incorporation of sulfate groups from persulfate catalyst or by conversion of non-ionic groups, which are already attached to the polymer by covalent bonds, converted to ionic groups.

The ionic groups are advantageously carboxylic acid salt groups, especially the alkali metal and ammonium carboxylic acid salt groups or quaternary ammonium salt groups, but other anionic and cationic groups are also useful, such as sulfate, sulfonate and

Amino groups. Carboxylic acid salt groups are particularly advantageous.

In latex compositions which contain little or no portion of ionic groups attached to the polymer, ionic stabilization can be achieved by adsorbed ionic surfactants. Small amounts of ionic surfactants can be used with latex materials that already contain ionic groups, but increasing amounts of surfactants beyond the range needed for appropriate stabilization usually cause the appropriate selection of the other components of the system becomes more critical, and this also complicates the wording.

Anionic and cationic surfactants are well known to those skilled in the art, and suitable materials from these classes can be selected, for example, from those described in the annual editions of McCutcheon's Detergents and Emulsifiers, for example, the 1973 edition published by McCucheon's Division, Allured Publishing Corporation, Ridgewood, NJ Examples of nonionic surfactants are also included in the above reference.

The particularly preferred latex materials (i.e. latex materials containing 0.09 to 0.18 milliequivalents of bound charge per gram of polymer) are generally the most suitable for carrying out the process of the invention and result in sheets with the best average binding. If these particularly preferred latex materials are used in carrying out the method according to the invention, the procedure in the step of colloid destabilization, as well as in the selection of the amount and type of the other materials, is less critical within the limits described. With such latex materials, observation of behavior during the process provides guidance for the selection of various other components to be used when it is desired to use latex types that are within the preferred and processable boundary conditions, but outside the most preferred limits. For this purpose, the following should be stated for the purpose of explanation: When the colloid destabilization step is carried out using the preferred method of using a flocculant which has a charge opposite to that of the latex, the appearance and type of the flocculated material obtained in this way result in the use of a particularly preferred latex material Specialists in the critical selection of other components, if a latex is used outside the particularly preferred range, but within the processable limits, valuable information, such as is the case, for example, with latex types with a higher bound charge.

There are certain cases where, for certain purposes, it is preferred to use latex types that contain a bound charge content of more than 0.18 and even more than 0.4 milliequivalents of charge per gram of polymer in the latex, for example when the bound one Charge is cationic when the re-breakability of the composition is desired or when the bound ionic groups, in addition to their stabilizing function, are desired in larger amounts in order to exert other advantageous interactions with other components of the composition.

The ratio of charge to mass, which is given here in milliequivalents of charge per gram of polymer in the latex, does not necessarily (and generally is not) the proportion in milliequivalents, for example

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correspond to valents of a monomer which contains an ionic group and which is copolymerized with non-ionic hydrophobic monomers by emulsion polymerization to form the latex. This difference occurs for several reasons, namely (1) because some of the ionic monomers are held inside the latex particle by polymerization and, accordingly, are not effective to stabilize the dispersion of the polymer, and likewise these particles are not measured; (2) the ionic monomer can be homopolymerized or copolymerized to form various amounts of water-soluble polymers, or (3) in some cases the ionic monomer does not polymerize as completely as other monomers. In general, it is the case that the proportion of ionic groups of the ionic monomer which are located on the surface of the latex particles and the proportion which is present within the latex particles decreases as the content of ionic monomers increases compared to the total amount of monomers or which forms ionic water-soluble polymers increases. Because too large a proportion of water-soluble polymers, either anionic or non-ionic, can cause difficulties in the process according to the invention, it is generally desirable to use (a) types of latex in cases in which bound charge is desired in higher concentrations, certain special precautions have been taken in their manufacture to minimize the formation of water-soluble polymers, or (b) to add materials that render the water-soluble polymers insoluble, or (c) to remove some or all of the water-soluble polymers.

Latexes of any readily available particle size are applicable to the practice of the present invention, but average particle diameters from about 1000 to 2600 Angstrom units are preferred, and especially in the range from 1200 to about 1800 Angstrom. Because the latex is diluted during the process, the solids content of the latex in the starting material is not critical.

In the production of many types of latex of various compositions which can be used in carrying out the process according to the invention, it is advantageous to use known chain transfer agents, such as various types of long-chain mercaptans, bromoform and carbon tetrachloride.

The fillers used in the practice of the present process are finely divided, substantially water-insoluble inorganic materials. Such materials include titanium dioxide, amorphous silicon oxide, zinc oxide, barium sulfate, calcium carbonate, calcium sulfate, aluminum silicate, clay, magnesium silicate, diatomaceous earth, aluminum trihydrate (aluminum oxide hydrate), magnesium carbonate, partially burned dolomitic limestone, magnesium hydroxide and mixtures of two or more of the above listed materials. Magnesium hydroxide is particularly well suited for use on conventional and commercially available paper making devices, thereby obtaining a product which has good properties; for example, it is flame retardant and resistant to microbiological attack, and accordingly this product is preferred. However, calcium carbonate is also sometimes preferred, especially in applications where the economic reasons are particularly important because this material is readily available, has a good structure, can be processed easily, and the less cleaned materials, such as ground limestone , can be applied. The particle size of the filler is in particular such that the main proportion of the material has a particle size of less than 50 microns in diameter. The average diameter of the particle size is generally above about 0.1 micron, and is preferably in the range between 0.1 and 20 micron. For preferred versions, the filler should be free from asbestos-like impurities.

In many embodiments of the process according to the invention, a flocculant or destabilizing agent (sometimes also as a deposition aid) is used with great advantage. Such flocculants are water dispersible and preferably water soluble ionic compounds or polymers, i.e. Compounds or polymers that carry a positive or negative charge. A flocculant which has a charge which is opposite to that of the ionically stabilized latex is normally used to carry out the process according to the invention. If the latex has a negative charge, the flocculant carries a cationic charge, or an anionic charge if the latex is positively charged. However, when combinations of two or more flocculants are used, they do not all have to have a charge opposite to the initial charge of the latex.

Preferred examples of flocculants are cationic starch, water-soluble inorganic salts such as alum, aluminum sulfate, calcium chloride and magnesium chloride, an ionic latex which has a charge with opposite signs (+ or -) to that of the binder latex, such as a cationic latex or an anionic latex; water-soluble ionic synthetic organic polymers, such as, for example, polyethyleneimine and various ionic polyacrylamides, such as, for example, carboxyl-containing polyacrylamides, copolymers of acrylamide with dimethylaminoethyl methacrylate or diallyldimethylammonium chloride, polyacrylamides which have been modified in a manner other than by copolymerization so that they are ionic Carrying groups, and combinations of two or more of the agents listed above, which are added simultaneously or sequentially. Quaternized polyacrylic amide derivatives are particularly advantageous when the latex used is anionic. Polymeric flocculants are preferred because they are more effective and result in less water sensitive products and better product abrasion resistance.

The preferred procedure for producing the products described is particularly suitable for producing hand-made papers or for using conventional continuous paper-making devices, such as, for example, a Fourdrinier machine, a cylinder machine (calender machine), suction machines, such as, for example, a rotary former, or a carton-making machine (Hart -carton manufacturing) device. Other well-known modifications of such equipment are also suitable for the preferred embodiments of the method according to the invention, such as a Fourdrinier machine with secondary head boxes or multi-cylinder machines in which, if desired, different starting materials can be used for the different cylinders (calenders) , whereby one can change the composition and the property of one or more different layers, which then result in the finished cardboard material. For further details, reference is made to the general summary on paper and paper manufacture, as can be found, for example, in the "Encyclopedia of Chemical Technology", pages 494 to 510, edited by Kirk-Othmer, the sheet production and suitable devices for this on the Pages 505-508 are described.

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In a preferred embodiment of the method according to the invention, the fiber material is mechanically processed in the presence of water, specifically in the way it is referred to in pulp production, pulping, grinding work (fine calendering, impact calendering), or treatment in a pulp mill. Cellulose fibers for carrying out the process according to the invention are generally ground to a “Canadian Standard Freeness” (CSF) with a consistency of 0.3% from approximately 300 ml to approximately 700 ml and preferably to a CSF value of 400 ml to approximately 600 ml. Synthetic Fibers can be mechanically treated in a similar manner, but if they are not specially treated, they do not fibrillate to give the same degree of dispersion as is obtained with cellulose pulps, so the Canadian Standard Freeness Test is not particularly suitable for such materials. The synthetic fibers generally have a fiber length of up to 9.5 mm, and preferably from about 3.2 mm to about 6.4 mm.

The consistency (percentage by weight of dry fibrous material) of the starting material so obtained is usually in the range from about 0.1% to about 6%, and preferably in the range from about 0.5% to about 3%.

When the fiber material is mixed with other components of the sheet, additional water is usually introduced to reduce the consistency of the starting material thus obtained, usually in a range between about 0.1% to about 6%, and preferably in a range between about 1% and about 5%. Part of the water that is used for the dilution is advantageously pure water (white water), or process water, which is recovered from later process steps of the sheet production process. Alternatively or additionally, a portion of the process water can also be processed in the step of grinding the fibers. Typically, the filler, dilution water and latex are generally diluted to a lower solids content than they were made with and added to the fiber dispersion in this order (usually but not necessarily) with stirring. At least part of the colloidal detabilization required can occur simultaneously with the mixing of the fibers, the filler and the latex, either through the interaction of these materials, or through the competitive addition of other, if applicable, additives to the wet end, for example those listed below. The mechanical shear stress exerted by the mixing and transportation of the material through the processing device can cause or aid destabilization. However, the combination of the mixing and destabilization steps gives fibrous agglomerates in aqueous suspension, which preferably have a concentration of 100 g solids in 13500 ml of the aqueous suspension, and which usually take 4-120 seconds, and preferably drain between 15 and 60 seconds, and particularly preferably in a time range between 30 and 45 seconds, if a 25.4 x 30.5 cm Williams standard film mold is used which has a 5.1 cm outlet and a 76.2 cm water pipe branch, and is equipped with a standard sieve with a mesh size of 0.143 mm made of stainless steel (wire size, diameter = 0.114 mm), whereby at least 85% of the solids, which are at least 60% by weight, can remain in one pass % Filler included. In addition, in the preferred embodiments of the method according to the invention, the drainage water is essentially clear. An effective and preferred way of performing (or completing the execution) of the destabilization is to mix the other components with a flocculant, e.g. a water-dispersible or water-soluble ionic material which carries a charge opposite to that (+ or -) which ensures ionic stabilization, and a sufficient amount of this addition is generally less than 1% by weight, based on the total Dry weight of the components. If preferred, a flocculant is added so that destabilization can take place before the distribution and drainage step is carried out. In continuous sheet making devices, such as the Fourdrinier papermaking machine, the flocculant is usually added in the reservoir or at some point in the feedstock feed line of the device to allow enough time for the desired effect to occur, but not to very much so that the flocculated starting material is exposed to undesirably high shear forces. After the aqueous dispersion thus obtained has been distributed and drained, the wet nonwoven obtained in this way can, if appropriate, be wet-pressed and then dried using devices which are usually used in papermaking.

The process temperature during the step of making the wet nonwoven is usually in the range of 4.4 ° C to about 54 ° C. Although temperatures outside of this range can be used if they are above the freezing point of the aqueous dispersion and below the temperature at which the latex polymer would undesirably soften. Sometimes temperatures above room temperature facilitate faster drainage.

When carrying out the present process, small amounts of various other additives to the wet end, as are usually used in papermaking, are also advantageous. Such materials are, for example, antioxidants, various hydrocarbon and natural waxes, in particular in the form of anionic or cationic emulsions; Cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; water-soluble organic dyes, water-insoluble but water-dispersible coloring pigments, such as, for example, carbon black, vat dyes and sulfur dyes; Starch, natural gums such as guar gums and carob gums, especially their anionic and cationic derivatives; non-ionic acrylamidopolymers; strength-increasing resins, such as, for example, melamine-formaldehyde resins, urea-formaldehyde resins and curing agents of various types, such as, for example, sulfur-containing vulcanizing agents and other auxiliaries. Additional amounts and / or types of anionic or cationic surfactants can also be introduced in small amounts at various points in the process, if desired. Non-ionic surfactants should be used sparingly, if at all.

If necessary, either internal or external sizing can be used together with the innovations according to the invention.

The densities of the products obtained from the process described above cover a wide range, such as from about 0.48 g / cm3 to about 2.4 g / cm3. Because the filler material makes up such a large proportion of the weight of the product, the type of filler selected for a specific product has a significant impact on the density and other properties of the product.

The thickness of the sheets that can be made

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vary from about 0.076 mm to about 3.17 mm, the preferred range being somewhat dependent on the intended use. Generally, however, the thickness ranges between about 0.38 mm and about 1.65 mm. The method according to the invention enables the production of self-supporting sheets separated from water with a high filler load, a high proportion of the filler being added to the starting material being retained in the sheets. As is commonly used in the art, the term "sheet separated from water" means a sheet which is deposited from a dilute aqueous suspension which usually has a solids content of 4% or less. While the filler forms the main part of the sheet, the latex and fiber parts are also retained to a high degree in the sheet. The retention in the sheet, based on all solids used in the process, is generally higher than 85% by weight and in the preferred embodiments higher than 95% by weight.

The method according to the invention and the product produced by this method have many advantages. Compared to sheets of paper made according to the state of the art, there is a lower moisture content in the sheet when it emerges from the wet end of the machine. Accordingly, based on the same sheet weight, less energy is required to dry the sheet, and the manufacturing device can operate at a higher speed or a thicker sheet can be dried. The novel method can be carried out using conventional devices or devices that are usually available in the paper manufacturing process. Easily available raw materials are used. A large part of the raw materials is the cheap filler and the total costs are low. The density can be changed easily by selecting the filler. The preferred embodiments are also asbestos free.

The invention will now be explained in more detail with the aid of the following examples, namely preferred embodiments of the present invention. All parts and percentages are percentages by weight or parts by weight unless otherwise expressly stated. The components identified by the letter names, such as latex A, are described in Tables A, B, C and D.

Table A fillers

Description- Description of the filler

A magnesium hydroxide; Particle size 5-10 microns in aqueous slurry with 58% solids.

B calcium carbonate; No. 9 chalk average particle size 15 microns.

C zinc oxide; Particle size: less than 1% is retained on a Tyler standard sieve with a mesh size of 0.043 mm.

D titanium dioxide; Particle size: less than 0.2%

are retained on a standard Tyler sieve with a mesh size of 0.043 mm.

E Mixture of 50% filler A and 50% filler N.

F mixture of 80% filler A and 20% filler B.

G mixture of 60% filler A and 40% filler B.

H barium sulfate; average particle size 2.5 microns.

Description- Description of the filler

J talk; average particle size 2.7 microns.

K H.T. clay, average particle size 0.8 micron.

L Alumina trihydrate, particle size: 75% pass through a Tyler standard sieve with a mesh size of 0.043 mm.

M Magnesium carbonate: Particle size: 90% pass through a Tyler standard sieve with a mesh size of 0.075 mm.

N expanded pearlite; Particle size: 1 to 16%

are retained on a Tyler standard sieve with a mesh size of 0.043 mm.

O magnesium hydroxide; Particle size 5 to 10 microns in powder form.

P water-washed paper filler grade clay,

average particle size 3 microns.

Q Talk, average particle size 9 microns.

Table B

Latex types

Description- description

nung

A A mixture of 65 parts (based on

Solid base) of a latex made from a copolymer of 56% styrene and 44% butadiene, prepared with 1% bromoform chain transfer agent and containing 5% diantrium salt of dodecyldiphenyl ether disulfonic acid and 4% of a modified resin soap, the percentages based on the copolymer weight, at 35 Parts of latex G and additionally 0.2%, based on the total polymer weight in the mixture, tridecyl sodium sulfate, the mixture thus obtained having a bound charge fraction between 0.02 and 0.06 milliequivalents per gram of polymer.

B A mixture of 75 parts (on a solid basis)

a latex made from a copolymer of 50% styrene and 50% butadiene made with 1% bromoform chain transfer agent and containing 0.5% of the diantrium salt of dodecylbiphenyl ether disulfonic acid and 4% of a modified resin soap, the percentages being based on the weight of the copolymer , with 25 parts (on a solid basis) of latex G, and wherein the mixture has a proportion of bound charges between 0.02 and 0.06 milliequivalents per gram of copolymer.

C latex made from a copolymer of 41% styrene, 55%

Butadiene, 3% itaconic acid and 1% acrylic acid, made with 1.5%

Bromoform chain transfer agent and containing 0.5% of the disodium salt of dodecylbiphenyl ether disulfonic acid, the percentages being based on the weight of the polymer in the latex. The bound charges are 0.144 milliequivalents of weak acid (carboxyl groups) and 0.058 milliequivalents of strong acid (sulfate) per gram of copolymer.

D Mix of 80 parts of latex C with 20 parts of latex

G with a bound charge fraction of 0.15 to 0.2 milliequivalents per gram of polymer.

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Description Description

E mixture of 80 parts of latex C and 20 parts of one

Latex from a copolymer of 80% styrene and 20% butadiene, containing 0.1% disodium salt of dodecyldiphenyl ether disulfonic acid, the mixture having a bound charge fraction between 0.15 and 0.2 milliequivalents per gram of copolymer.

F blend like latex A, except that the amount of latex G in the blend is 30% instead of 35% and the blend has a bound charge between 0.02 and 0.06 milliequivalents per gram of polymer.

G latex made from a copolymer of 81% styrene, 17% butadiene and 2% acrylic acid made with 2% carbon tetrachloride chain transfer agent and containing 0.2% tridecyl sodium sulfate, the percentages being based on the weight of the copolymer in the latex. The bound charge fraction of the latex is 0.065 milliequivalents per gram of copolymer.

H A mixture of 70 parts (on a solid basis)

a latex made from a copolymer of 50% styrene and 50% butadiene, made with 1% bromoform chain transfer agent and containing 0.5% of the disodium salt of dodecyldiphenyl ether disulfonic acid and 4% of a modified resin soap, the percentages based on the copolymer weight 30 parts (on a solids basis) of latex C, the mixture having a bound charge proportion between 0.07 and 0.1 milliequivalents per gram of copolymers.

J A polychloroprene latex that is stabilized with a resin soap and that has essentially no measurable bound charges.

K A latex made from a copolymer of 95.5% ethyl acrylate, 2% acrylamide and 2.5% N-methyl acrylamide containing 0.5% sodium lauryl sulfate with an average particle diameter of 900 • 10 ~ 10, all percentages based on the copolymer weight, and the amount of charge bound is less than 0.03 milliequivalents per gram of copolymers.

L A latex made from a copolymer of 65% styrene and 35% butadiene, made with 0.2% dodecanethiol chain transfer agent, stabilized by 4%

Dedecylbenzyl-trimethylammonium chloride as a surfactant, with an average particle diameter of 750-10-10m, all percentages based on the weight of the copolymer, and which material has a bound landing fraction of less than 0.02 milliequivalents per gram of copolymer.

M latex made from a copolymer of 90%

Vinylidene chloride, 5% butyl acrylate and 5% acrylonitrile obtained by competing polymerizing the monomers with 1.4% sulfoethyl methyl acrylate and this material having an average particle diameter of 1200 angstroms, and all percentages based on weight

Description- Description of the copolymer are calculated, and the material has a bound charge fraction of 0.03 to 0.04 milliequivalents per gram of copolymer.

N A mixture of 70 parts (on a solid basis)

a latex from a copolymer of 49% styrene, 50% butadiene and 1% itaconic acid, prepared in the presence of 6% carbon tetrachloride and containing 0.75% disodium salt of dodecyldiphenyl ether disulfonic acid, with 30 parts (on a solid basis) latex G. The mixture shows a bound charge of 0.116 milliequivalents of weak acid (carboxyl groups) and 0.031 milliequivalents of strong acid (sulfate) per gram of the polymer in the blend, and all percentages are by weight of the particular copolymer.

A latex made from a copolymer of 48% styrene,

50% butyl acrylate and 2% acrylic acid, containing 0.5% of the disodium salt of dodecyldiphenyl ether disulfonic acid, the percentages based on the weight of the copolymer. The latex has a bound charge of 0.071 milliequivalents of acid (carboxyl groups) per gram of copolymer.

P A latex like the latex O, but with the

Except that the copolymer composition contains 46% styrene, 50% butyl acrylate and 4% acrylic acid and that the bound charge is 0.092 milliequivalents (carboxyl groups) per gram of copolymer.

Q A latex made from a copolymer of 69%

Vinylidene chloride, 4.9% butyl acrylate, 24.7% acrylonitrile and 1.4% 2-sulfoethyl methacrylate. The bound charge portion is 0.039 milliequivalents per gram of copolymer.

RA latex made by copolymerization of

35% styrene, 55% butadiene and 10% acrylic acid in the presence of 8%

Carbon tetrachloride chain transfer agent and 0.75% ammonium persulfate catalyst and 0.5 part disodium salt of dodecyldiphenyl ether disulfonic acid, all percentages being given based on total monomer weight. The amount of charge bound is 0.268 milliequivalents of weak acid (carboxyl groups) and 0.091 milliequivalents of strong acid (sulate) per gram of the copolymer. The pH of the latex is 3.4.

Table C fiber materials

Description Description

A Bleached softwood kraft pulp.

B Bleached hardwood kraft pulp.

C Mixture of 50% fibers A and 50% fibers B.

D Unbleached pine (southern pine) power pulp.

E Unbleached softwood (northern softwood)

Kraftpulp.

F Unbleached softwood sulfite pulp.

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40

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Description Description

G SWP fibrillated polyethylene fibers; E-400, fiber length 0.9 mm.

H SWP fibrillated polyethylene; R-830, fiber length 2.0 mm.

I SWP fibrillated polyethylene; R-990, fiber length 2.5

mm

J Mixture of 50% fibers I and 50% fibers D.

K mixture of 25% fibers I and 75% fibers D.

L mixture of 50% fibers G and 50% fibers D.

M polyester (polyethylene terephthalate) 6.0 denier per filament; Fiber length 0.135mm.

N nylon 66, 3.0 denier per filament; Fiber length 0.25 mm.

O rayon; 5.5 denier per filament; Fiber length 0.135 mm.

P rock wool.

Q Mixture of 50% fibers D and 50% fibers P.

R mixture of 75% fibers E, 12.5%

Polyethylene terephthalate fibers with 3 deniers per filament and a length of (6.35 mm and 12.5% starch-coated glass fibers with a length of 6.35 mm) and 6 millimeters in diameter.

Table D flocculant

Description Description

A A copolymer of acrylamide and

Dimethylaminoethyl methacrylate, which was quaternized with dimethyl sulfate (Betz 1260), and which has an Ostwald viscosity of 0.017 Pa-s in 0.5 percent aqueous solution containing 3% sodium chloride at 25 ° C.

B A Mannich reaction product made from polyacrylamide,

Formaldehyde and dimethylamine which is quaternized with methyl chloride, the quaternized product thus obtained being as described in U.S. Patent No. 4010131 to Philips et al. issued on March 1, 1977, and the reaction product has an Ostwald viscosity of 30 centipoises in a 0.5 percent aqueous solution containing 3% sodium chloride at 25 ° C.

C alum.

D A high molecular weight polyacrylamide that is about 5% hydrolyzed and has a viscosity of 0.023 Pa-s when measured at 25 ° C in a 0.5 percent aqueous solution.

E A terpolymer made of acrylamide,

Methylallylammonium chloride and diethyldiallylammonium chloride with an Ostwald viscosity of 0.0037 Ps • s in a 0.5 percent aqueous solution containing 3% sodium chloride at 25ºC.

As far as hand-made sheets are produced in the examples, a specially developed standard technique is used, with the modifications as indicated in the examples. In the standard technique, the specified fiber (if it is a cellulose fiber) is processed into a pulp which has a Canadian Standard Freeness (CSF) value of 500 ml and a consistency of approximately 1.2% by weight. The synthetic fibers are dispersed in water using a Tappi disintegrator (600 Hertz) and no Canadian Standard Freeness (CSF) measurement is made. With a sufficient amount of the aqueous dispersion obtained to provide 5 g of dry-based fibers, another pre-calculated amount of water is mixed to give a final volume of 2000 ml. Stirring is continued while 80 g of the specified filler is added, in powder form except where indicated as an aqueous slurry, and then 15 g (on a solids basis) of the specified latex are added. The mixture thus obtained is mechanically ground in a Jabsco centrifugal pump (centrifugal pump) for 15 seconds and then stirred with a laboratory stirrer equipped with a 3-blade impeller on a shaft at 900 revolutions, while a 0.1% solution of the specified flocculant is slowly added until the water phase is essentially clear. A sufficient amount (about 62 ml) of the raw material thus prepared, which contains 3 g of solids, is diluted to 1000 ml with water, and the Canadian Standard Freeness (CSF) value is determined in accordance with Tappi Standard T 227-M-58. The sample from the Röschheiztest is added back to the raw material and diluted to 13500 ml and a sheet is produced in a 25.4 x 30.48 cm Williams standard sheet form, and the drainage time is recorded on a mesh size of 0.147 mm. The wet sheet thus obtained is squeezed from the screen in a press at about 70 kPa using two absorbent layers to absorb the water from the sheet. The sheets are alternately stacked with nonwoven paper intermediate layers and wet pressed with a pressure of 3500 kPa. The partially dried sheets are then weighed and then dried on a sheet drying device with a plate temperature of 116-121 ° C, alternately pressing both sides of the sheet against the plate at 0.5-1 minute intervals. The dried leaves so obtained were weighed to determine the total solids content retained in the sheet. After sufficient material was used to make a 100 g sheet with full retention, the dry weight directly indicated the percentage of retention.

Examples 1 to 14

Handmade paper sheets are made,

by using the specified latex types, unbleached pine (southern pine) kraft pulp and the specified fillers, and working with the flocculant A according to the standard techniques, but with the specified exceptions. The data for the manufacture of the leaves are summarized in Table I. The properties of the leaves are given in Table II.

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Table I

Sheet production with various fillers

Example no. Latex filler type amount of flocculant dryness of the drainage time in ml (a) raw material CSF in seconds in ml

1

A

A

40

630

79

2nd

B

E

245

650

30th

3rd

A

A

80

710

42

4th

A

C.

130

800

23

5

A

D

60

600

100

6

B

F

125

780

30th

7

B

G

220

800

18th

8th

B

B

370

840

15

9

F

I (b)

190

850

60

10th

B

H

160

785

9

11

B

J

180

730

7

12

B

K

300

790

7

13

B

L

360

850

13

14

H

M

240

700

20th

(a) 0.1 percent aqueous solution

(b) 75 parts filler and 10 parts fiber

Table II

Properties of the leaves with different fillers

Example dry-thick density tear strength (a)

No. Weight mm g / cm3 room temp. Hot (b) Taber stiffness (a)

in g kPa kPa Reg DOP H2O

1

95.5

1.42

5180

1680

390

30th

2nd

95.9

1.85

0.75

2800 (d)

700 (d)

22 (d)

5 (d)

2 (d)

3rd

88.1

1.32

3850

1050 (d)

360

23

4th

98.3

1.06

6160

2210

260

50

5

93.4

0.91

8890

3010

280

70

6

91.0

1.14

72.2

5740

1820

106 (c)

18 (d)

35 (d)

7

88.3

1.06

75.0

5600

1820

100 (c)

18 (d)

25 (d)

8th

88.7

0.96

84.2

5250

1190

94 (c)

20 (d)

. 16 (d)

9

96.0

20.8

1820

10th

96.5

0.73

116

8190 (6d)

2660 (d)

150 (d)

30 (d)

21 (d)

11

99.3

1.21

72

4130

1400 (d)

87 (d)

17 (d)

12 (d)

12

99.0

1.14

78

3710 (d)

1820 (d)

98 (d)

3 (d)

12 (d)

13

99.0

1.17

1.01

2520 (d)

630 (d)

29 (d)

4 (d)

4 (d)

14

92.5

0.91

1.44

2870 (d)

490 (d)

(a) Average from three samples unless otherwise stated (c) Average from four samples. 50 (d) Average of two samples.

(b) At 177 ° X

Examples 15 to 42

Handmade paper sheets were made from the specified latex types and the specified types of fibers, which were milled to the specified freshness (Canadian Standard Freeness (CSF)) and the specified fillers and the specified flocculants according to the standard procedure outlined above, with the exceptions 55 which are specified Sheet production data are summarized in Table III and sheet property data are summarized in Table IV.

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Table III

Production of sheets with different fibers

fiber

Flocculant

Serenity of

Drainage time

example

latex

filler

CSF

amount

Raw material CSF

in

No.

art art

Art ml

Art ml ml

Seconds

15

C.

A

A 600

B

330

560

113

16

c

A

A 500

B

340

580

76

17th

c

A

A 400

B

330

590

87

18th

D

A

A 600

B

280

550

62

19th

D

A

A 500

B

280

580

62

20th

D

A

A 400

B

300

560

71

21st

D

A

B 600

B

310

660

55

22

D

A

B 500

B

300

650

57

23

D

A

B 400

B

315

620

47

24th

D

A

C 500

B

330

635

64

25th

D

A

D 500

B

325

700

55

26

D

A

E 500

B

315

730

33

27th

D

A

F 500

B

325

700

51

28

C.

F

D 500

A

440

610

66

29

C.

F

G

A

420

600

43

30th

C.

F

H

A

440

550

37

31

C.

F

I.

A

340

620

62

32

C.

F

J

A

380

700

34

33

C.

F

K

A

380

610

39

34

C.

H

L

A

800

-

33

35

F

A

M -

A

140

740

30th

36

F

A *

M * -

A

170

800

22

37

F

A

N

A

160

750

40

38

F

A *

N * -

A

170

780

23

39

F

A

O

A

160

700

41

40

F

A

D 500

A

110

700

91

41

A

A

p * _

A

70

720

27th

42

A

A

Q * -

A

45

770

18th

* 10 parts fiber, 75 parts filler.

Tahellft TV

Leaf properties when using different fibers

example

Dry

thickness

density

Tear resistance

No.

weight mm g / cm3

Room temp. (a)

Hot (b)

Taber stiffness

G

kPa

kPa

Reg

15

90.1

1.14

1.18

4410

51

16

94.3

1.22

1.14

4760

50

17th

94.5

1.19

1.16

4690

57

18th

92.1

1.24

1.09

5600

69

19th

94.1

1.19

1.14

810

74

20th

91.8

1.17

1.14

5600

75

21st

96.0

1.17

1.20

5460

73

22

96.1

1.19

1.17

6160

82

23

95.2

1.19

1.15

5950

83

24th

95.1

1.19

1.15

5880

89

25th

99.1

1.39

1.05

5110

62

26

97.8

1.27

1.16

7910

82

27th

96.8

1.29

1.08

6510

82

28

88.6

1.17

1.30

6300 (b)

3990

29

91.5

1.24

1.26

1960 (b)

840

30th

91.0

1.17

1.25

2030 (b)

700

31

88.3

1.29

1.17

1610 (c)

770

32

94.9

1.24

1.31

3290 (b)

1680

33

96.3

1.27

1.30

3430 (b)

238

34

98.3

0.71

2.16

3500 (b)

1890

35

90.0

1.24

6510

980

84

36

96.5

1.34

9030

1470

110

37

96.6

1.37

2870

770

72

38

95.5

1.47

3920

112

72

39

94.9

1.32

1855

350

58

40

97.8

1.32

7910

2310

108

41

91.0

1.37

0.946

2430

490

25th

42

96.1

1.47

0.954

4690

1440

31

(a) Average from 3 samples unless otherwise stated. (c) A sample.

(b) Average from 2 samples unless otherwise stated.

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Examples 43 to 46

Handmade paper sheets were made following the standard procedure outlined above, using fiber B as the fiber, for example, latex filler,

Art

43 J B

44 K A

45 L A

46 M A

Table VI Properties of the leaves

example

Dry weight g

Thickness mm

Density kPa

Tear resistance

Room temp.

kPa

Hot kPa

43

85.2

44

92.5

1.22

2340

994

45

89.0

1.27

1,045

91

280

46

87.8

1.27

4060

1890

Examples 47 to 49

Handmade paper sheets are made according to the standard process described above, with the fibers being unbleached softwood kraft pulp, latex latex type B, filler = filler type A, and flocculant as indicated. In addition to the flocculant, the specified amount of alum was added first, followed by stirring for 1 minute

Example weight thickness in

No. in g mm

47 95.8 50

48 102.2 53

49 100.2 51

Examples 50 to 53

Handmade paper sheets were made according to the standard procedure described above,

the fibers, latex and flocculant are given in Table IX and the filler = filler type A was in the amount indicated. The data for the manufacture of the leaves are summarized in Table IX. Samples of the leaves were treated in a tropical climate chamber at 100% relative humidity and 32.2 ° C, which had previously been inoculated with microorganisms Aspergillus niger, Trichoderma viridie, Aureobasidium pullulans, Chaetomium globosum and an unidentified type of penicillin. At the end of the 21 days and 49 days, samples were examined for visible microbiological attack and loss values of tensile strength at room temperature were measured on strips that were 7.62 cm long and 2.54 cm wide. For comparison purposes, hand-made materials were used and the filler, latex and flocculant were used as specified in Table V. The properties of the paper sheets thus produced are shown in Table VI.

Freshness of the drainage time

Raw material in in CSF seconds

820 15

800 9

850 5

450 46

a sufficient amount of the other flocculant was added to complete the flocculation. The data for the production of the handmade paper sheets are summarized in Table VII, the properties of the sheets are listed in Table VIII.

25 Table VII

Making the leaves

With- flocculant roughness of the game C (a) A (b) B (B) raw material drainage time

No. ml ml ml CSF in ml in seconds

47

12

0

0

600

50

48

6

54

0

700

29

49

6

0

80

650

24th

35

(a) In the form of a 5 percent aqueous solution.

(b) In the form of a 0.1% aqueous solution.

Tear resistance - Taber stiffness hot in kPa Reg DOP

1393 71 13

1064 69 10

1596 99 15

Paper sheets made of 85 parts of asbestos (Johns Manville, Paperbe-stos No. 5) and 15 parts of latex C (comparative example A-l) and 85 parts of asbestos and 15 parts of latex B (comparative example

55 game A-2). The test data are summarized in Table X.

The visual assessment is based on an arbitrary scale for visible microbiological attack as follows:

60 0 = no attack

1 = very weak attack

2 = weak attack

3 = moderate attack

4 = strong attack o5 5 = very strong attack

The tensile tests were carried out in the same manner as this except for the length of the test strips

Table V Manufacture of leaves

Flocculant

Quantity type ml

A 60

B 150

D 500

A 70

Table VIII Properties of the leaves

Density in tear resistance

g / cm3 in kPa

1.27 3234

1.35 3234

1.30 4606

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End of the example section is described. The tensile strength data given in Table X are the percentage change in tensile strength between the test strips and the comparison strips of the same type that were produced simultaneously and were kept outside the tropical climate chamber for the same period of time.

Table IX

Production of sheets for the test in the tropical climate chamber

Example No.

Fiber Art

amount

Latex art

Filler quantity

Flocculant amount

Art ml

Roughness drainage time of the in

Raw material

CSF in ml seconds

50 D 5 B 80 B 165 (a) 770 27

51 A 10 B 75 A 200 (a) 790 42

52 A 10 B 75 C 70 (b) 650 38

53 A 10 C 75 B 460 (a) 700 40 A-l * 650 35 A-2 * 650 20

* Comparative examples of a sample not according to the invention

(a) In the form of a 0.1% aqueous solution

(b) In the form of a 5 percent aqueous solution

25th

Table X

Test values on leaves that were treated in the tropical climate chamber

example

No.

Weight in g

Visual assessment by days

21 49

Percentage change in tear strength after

21 days

49 days

50

51

52

53

A-l * A-2 *

98.2 96.9 95.8 96.8

2 1

1

2 1 1

-7.8 + 0.9 + 3.9 + 4.5 -3.1 + 2.9

0

+ 5.5 + 2.1 + 2.0 + 12.6 - 0.3

30th

Examples 54 to 60

Handmade sheets were made using the standard procedure described above, except that different ratios of fiber, latex and filler were used. The fibers were unbleached softwood kraft pulps and the latex was Type B latex, the filler was Type B filler and the flocculant was Type A flocculant. The 35 data are summarized in Table XI.

40

* Comparative examples with sheets not produced according to the invention.

Table XI

Different proportions of the components

For- fiber latex filler flocculence-freshness d. Draina leaf data game medium raw material tidal density density tear resistance

No. g g g ml CFS ml section% g / cm3 capacity kPa

54

1.0

19.0

80.0

215

520

15

89

1.26

2149

55

2.5

25.0

72.5

370

860

7

96

1.10

2674

56

5.0

30.0

65.0

630

860

4th

88

1.28

3346

57

10.0

10.0

80.0

102

810

9

89

1.10

6321

58

15.0

5.0

80.0

85

780

10th

92

1.08

7182

59

25.0

10.0

65.0

205

830

12

90

1.10

14693

60

5.0

5.0

90.0

100

850

21st

97

1.20

1953

Example 61 and 62

A handmade sheet (Example 61) is made by processing unbleached softwood kraft pulp, latex F, filler 0 and flocculant A according to the standard procedure outlined above. Another hand-made sheet (Example 62) is made in the same manner, except that 0.25 parts of a cationic polyamide epichlorohydrin resin (Kymene 557) in the form of a 0.132 percent solution of the aqueous fiber dispersion is added before mixing with filler and latex has been. The data are shown in Table XII.

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Table XII

Example 61 Example 62

Flocculant A, ml 150 150

Rawness of raw material CSF, 755 600 ml

Drainage time in seconds 50 110

Sheet thickness in mm 1.27 1.14

Leaf weight in g (% retention) 94.9 87.0

Density in g / cm3 1.09 1.09

Tear resistance in kPa 5600 6580

Tear resistance, hot at 177 ° C 2100 2240 in kPa

Examples 63 and 64

Handmade sheets were made by using latex N, fiber R and the specified filler, and flocculant E in the specified amount according to the standard procedure, except that a wet strength additive which is a cationic polyamide epichlorohydrin resin containing 12, Containing 8% nitrogen is added after the filler has been added in the amount shown in Table XIII and 1% based on the total weight of the solids, an anionic emulsified hydrocarbon wax has been added after the latex addition. A compilation of the data is given in Table XIII.

Table XIII

Example 63

Example 64

Filler P,% (solid basis)

77

Filler Q, ° / n (solid basis)

-

Latex N,% (solid basis)

15

77

Fiber R,% (solid basis)

8th

8th

Flocculant E, kg / ton of

1.07

0.49

Solids

Wet strength additive, kg / ton of

3.3

4.7

Solids

Drainage time in seconds

50

54

Leaf density in g / cm3

1.21

1.18

Tear resistance at

14532

12176

Room temperature, kPa

Tear resistance, hot, in kPa

5341

3514

Stiffness, DOP, kPa

6615

4725 '

Stiffness, water, kPa

7966

8134

Expansion, room temperature,%

3.5

2.7

Expansion at 177 ° C%

2.3

2.0 -

Extension, DOP,%

3.3

2.3

Expansion, water,%

6.3

5.0

* Water absorption,%

8.9

5.5

* Water swelling,% (length)

0.38

0.22

* The specimens were 6 inches (15 cm) instead of 4 inches (10 cm) long.

The products of these two examples are particularly suitable for materials for the production of floors in terms of their properties and in particular their dimensional stability in the presence of water.

Examples 65 to 70

Using the standard procedure, but with the exception that the mechanical shear work in one

Jabsco centrifugal pumps (centrifugal pumps) were omitted, hand-made sheets were made from the specified latex, fiber E and filler Q using the flocculant E in the proportions given in Table XIV for latex, fiber and flocculant, and the amount of filler represents the difference between 100% and the total amount of latex and fiber, where everything is calculated based on the dry solids. Quantities were also used to make hand-made leaves, which should theoretically weigh 75 g instead of 100 g, and the dilution water in the raw material was reduced accordingly. The data are summarized in Table XIV.

Table XIV Example No.

65

66

67

68

69

70

Latex, Art

O

O

P

P

Q

A

Quantity,% (a)

15

7.5

15

7.5

15

7.5

Fiber E, quantity% (a)

6

10th

6

10th

6

10th

Flocculant E,

2.71

1.65

3.29

1.93

3.29

1.93

Quantity in kg / t (a)

Drainage time in

97

59

64

41

122

61

Seconds

Tear resistance, 13636 10941 13083 14028 11991 10976

Room temp., KPa

(a) Based on dry solids.

* The percentage retention of all of these examples is greater than 92.

Example 71 and Test 71-C

8% (based on the solids content of the latex) carbon tetrachloride are mixed with a proportion of latex R. The product thus obtained is centrifuged off. The aqueous serum is removed and the remaining solids are washed with water. The crude solids so obtained are redispersed in water and then the solids and water are subjected to vigorous mixing for 30 minutes to 1 hour. The dispersion thus obtained is latex R-1 and has a pH of 3.8.

With the exception of using amounts that are theoretically sufficient to produce sheets weighing 30 g instead of sheets weighing 100 g and accordingly reducing the amount of water in the raw material, the standard procedure for the production of handmade sheets was carried out by using Latex R and Latex Rl in a ratio of 15% of the respective latex, 15% fiber E and 75% filler K (on a solid basis, calculated on the weight of the latex, fiber and filler content together), using 127 ml of a 0.1% aqueous solution of the Flocculant E carried out. Wet hand-made sheets were produced with both latex R-1 (example 71) and with latex R (comparative experiment 71-C) with 20 and 29 seconds drainage time. In Example 71, only a weakly detectable amount of foam was found in the production of the starting material, the sheet sticking only slightly to the wire screen when the moist, handmade sheet was dried. The progress of the flocculation is easily observed during the addition of the flocculant. In comparative example 71-C, however, a large amount of foam occurred during the production of the starting material. Accordingly, a solid adhesive was dried

5

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15

20th

25th

30th

35

40

45

50

55

60

o5

15

640 026

hand-made sheet found on the wire screen and on the suction paper, so that the sheet could not be separated from the wire mesh.

The bound charge share of latex R and latex R-1 is the same because the process for producing latex R-1 from latex R does not change the existing bound charge carriers (carboxyl groups). The clear difference is that latex R removes the water-soluble components such as surfactants and acrylic acid polymers or copolymers with a sufficiently low molecular weight and a sufficiently high carboxyl group content to be water-soluble. These results are consistent with the view that excessive amounts of water-soluble polymers, including surface-active agents and ionic polymers, are disadvantageous when carrying out the process according to the invention.

Examples 72 and 73

An aqueous fiber dispersion with about 4% consistency (solids content) was produced from bleached pine (southern pine) kraft pulp and water in a “Black Clawson Hydrapulper”. The crude dispersion was pumped into a grinder box and ground to a Canadian standard freeness of 500 ml by circulating through a Sprout-Waldron twin flow refiner. High filled sheets of Examples 72 and 73 were made from parts of this fiber dispersion, a latex and a filler as indicated in Table XV with their amounts using a 78.7 cm Fourdrinier paper making machine which uses a phosphor bronze wire mesh, It had 4 flat suction boxes between the end rollers and a suction rubber roller, a first nose press, a reversing press, a multi-zone drying device with a size press between the sections and a 7-roll calendering device. The fiber dispersion, filler, water and latex, diluted to 25% solids, were placed in the machine's reservoir in the order listed, calculating the water addition to give a 4% solids content . The starting material obtained in this way is transferred by means of a feed pump through a feed valve and then by means of a centrifugal pump into the head box. The flocculant shown in Table XV was added between the feed pump and the feed valve, and some clear water from the later steps of the process is returned to the system between the feed valve and the centrifugal pump so that the consistency (solids content) of the starting material in the head box as shown in Table XV. The raw material from the head box is applied to the wire mesh, which moves at 6.09 m per minute, where the clear water (white water) drips from the wet sheet, and additional water is removed from it by using the four suction boxes before the sheet is lifted off the wire screen at the suction rubber roller. After two press steps, the water content has decreased further and the sheet is fed into the drying and calendering system. The data for this process and the data regarding the properties of the highly filled sheets thus produced are summarized in Table XV.

Table XV

Example 72 Example 73

Filler A,% (solids basis) 75 80

Latec C,% (solids basis) 15

Latex F,% (solids basis) - 15

Bleached

10th

5

Softwood Kraft Pulp,%

(Solid base)

Flocculant A, kg / ton

-

0.58

Solids

Flocculant B, kg / ton

4.94

-

Solids

Solids content in

4.0

4.0

Storage container,%

Solids content in the head box,%

3.31

1.22

Canadian standard cuteness

603

668

in the head box, ml

Machine speed in m

6.1 •

6.1

per minute

Wet pressing, 1st press, kg / cm

3.6

3.6

Wet pressing, 2nd press, kg / cm

12.5

12.5

Retention,%

99

102

Caliber, mm

0.721

0.704

Density, g / cm3

0.936

0.904

Tear resistance, MD, kPa

5138

3220

Tear resistance, MD, kPa

3626

2863

Hot tensile strength, MD. kPa

2996

1330

Hot tensile strength, CD, kPa

2310

616

DOP tensile strength, MD, kPa

3794

945

Expansion, room temp. (R.T.),%

MD

3.1

2.0

CD

7.9

3.8

Expansion, hot,%

MD

2.0

1.7

CD

4.0

2.8

Expansion, DOP, MD,%

2.3

1.7

Stiffness, MD

Taber

119

119

DOP

81

29

water

20th

29

Stiffness, CD

Taber

81

72 '

DOP

46

12

water

14

19th

Elmendorf tensile strength, g-cm

MC

24.8

16.7

CD

24.7

11.7

Garbage tensile strength, kPa

156.8

107.1

Water absorption,%

14.1

10.3

Toluene uptake,%

49.9

54.2

Oxygen Limit Index (L.O.I.)

47

53

Example 74

An aqueous dispersion of fibers is produced, with a solids content of 4% of unbleached softwood (northern softwood) kraft pulps and water in a «Black Clawson Hydrapulper». The crude dispersion is introduced into a refining container and refined to a Canadian Standard Freeness of 500 ml by circulation through a Sprout-Waldron twin flow refiner. Highly filled sheets for Example 74 were made from a fiber dispersion, a latex and a filler as indicated, and man

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added a wet strength additive which is a cationic polyamide epichlorohydrin resin containing 12.8% nitrogen and having a viscosity at 25 ° C between 40 and 50 centipoises, all the materials listed in the amounts shown in Table XVI and a Fourdrinier papermaking machine was used which was equipped with (a) a 91.4 cm wide plastic net, (b) a head box with a distributor head inlet, a homogenizer roller and a nylon jamming device, (c) a suction rubber roller, ( d) a straight-running flat press, (e) a flat reversing press, (f) a dryer section, consisting of 7 and 5 dryers with completely cast treads and two felt dryers on the bottom and at the top of the runner grippers, and (g) a calender block, consisting of 8 Rollers, the intermediate rollers are pierced to introduce steam. The fiber dispersion, filler, wet strength additive, water and latex diluted to 25% solids were added to the machine reservoir in the order listed, with an amount of water calculated

that a consistency (solids content) of 4% was obtained. The starting material thus obtained was transferred by a feed pump through a feed valve and then by a centrifugal pump into the head box. The flocculant shown in Table XVI was fed between the feed pump and the feed valve, and some clear water (white water) derived from later process steps was returned to the system between the feed valve and the centrifugal pump so that the solids content of the starting material in the head box as indicated in Table XVI. The material from the head box is applied to the web moving at 12.2 m per minute, where the drained water drains from the wet sheet, from which further water is removed by using the suction boxes before the sheet is removed from the web is removed from the suction rubber roller. After the two press stages have further reduced the water content, the sheet is introduced into the dryer and calender block. The data for the implementation and the properties of the highly filled sheets thus produced are compiled in Table XVI.

Table XVI

Example 74

Filler B,% (on a solids basis) 82.5

Latex N,% (on a solid basis) 7.5

Fiber E,% (on a solids basis) 10.0

Flocculant E, kg / clay solids 0.37

Solids content in the storage container,% 4.0

Solids content in the head box,% 1.7

Canadian Standard Roastness (Canadian 568 Standard Freeness) in the head box, ml

Machine speed in m / min 12.2

Wet pressing, 1st press, kg / cm 17.8 Wet pressing, 2nd press, kg / cm

Retention,%> 90

Caliber, mm 0.584

Density, g / cm3 0.80

Tear resistance, MD, kPa 11200

Tear resistance, CD, kPa 4550 stiffness, CD

Taber 48

MD 136

Example 74

CD

160

Mullen tear strength, kPa

259

Kerosene uptake,%

64.4

The various tests that were carried out are those listed below with further modifications as described in more detail in the individual examples.

Canadian Standard Freeness (CSF) test:

The value in ml is determined in accordance with the TAPPI standard T 227-M-58 on a sample which contains 3 g of solids diluted with 1000 ml of water.

Elmendorf tensile strength:

The test is carried out according to the TAPPI method T414-ts-65. The results are given as an average of at least 3 samples.

Percentage expansion:

The expansion at room temperature, the expansion at 177 ° C (hot), the expansion DOP and the expansion at water were carried out at a span of 15.24 cm simultaneously with the corresponding tear resistance tests, description see below.

Limiting Oxygen Index (L.O.I.): The L.O.I. was determined according to the ASTM-D-2863-74 test.

Mullen burst limit (bull burst):

The TAPPI test method D 403-os-76 was used, except that the test was carried out on thicker leaves. The results given are average values from 4 or 5 samples.

Percentage retention:

The materials for the hand-made leaves are used in amounts sufficient to give leaves weighing 100 g. Accordingly, the dry weight of the product indicates the percentage yield or retention of solids in the sheet.

For the sheets produced on the Fourdrinier machine, the percentage retention relates to the proportion of the filler that was contained in the sheet. The combustion of the test samples was carried out under conditions such that the residue contained the filler (calculated as percent ash) but the other components were removed. The percentage ash content was multiplied by a suitable factor to correct the changes in the filler due to the combustion (for example Mg (OH) 2 MgO) and thus calculate the percentage filler in the sheet. From the percentage of filler found in the sheet and the added percentage of filler (based on solids), the percentage of the amount of filler retained in the sheet was calculated based on an average of 3 samples.

Taber stiffness:

The Taber stiffness (g-cm) was determined according to the TAP-PI standard method T 489-os-76, but with the

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Except that an average of 3 samples was used unless otherwise noted. The value obtained was corrected for a value of 30 mm thickness by using the factor

W

(Thickness of the test sample in mm x 0.0254) '

multiplied. To distinguish the modified Taber stiffness tests (DOP and water - as described below), the TAPPI method was sometimes referred to in the present description as “Taber stiffness, reg.” designated.

Stiffness DOP:

The DOP stiffness (g-cm) is determined in the same way as the Taber stiffness, except that the sample was soaked in dioctyl phthalate for 18 to 24 hours before the test, and the value given is the average of 2 samples .

Stiffness, water:

The stiffness under the influence of water is determined in the same way as the Taber stiffness, except that the sample was soaked in water for 18 to 24 hours before the test was carried out, and the values given are average values from two samples.

The tensile strength at room temperature (R.T.):

The sheets were cut into 2.54 x 20.32 cm strips and the minimum thickness in the test area was determined. The strip to be tested was clamped in an Instron test device with a span of 15.24 cm. While the Instron test machine was operating at a head speed of 25.4 mm per minute, the expansion and load in pounds at break were measured.

The breaking load in kPa was calculated by dividing the breaking tensile force by the thickness of the sample. The results are given as an average of 3 samples.

Tear resistance, hot:

The hot tensile strength was determined in the same manner as that at room temperature, except that the test sample was heated to 177 ° C immediately before the test while it was clamped in the tester of the test machine.

Tear resistance, DOP:

The tensile strength DOP was checked in the same way as the tensile strength at room temperature,

however, except that the test sample was soaked in dioctyl phthalate for 24 hours prior to testing.

Tear resistance, water:

The tensile strength with water was determined in the same way as the tensile strength DOP, except that it was soaked in water.

Toluene intake:

A suitable 5.08 x 10.16 cm sample was soaked in toluene for 15 seconds and the weight gain was determined and the weight percent calculated.

Kerosene uptake:

Kerosene uptake was determined in the same way as toluene uptake, except that it was soaked in kerosene.

Water intake:

The water uptake was determined in the same way as the toluene uptake, except that it was soaked in water for 24 hours.

Water swelling:

The water swelling was determined on the same test piece that was determined for the water absorption and was calculated from the length extension of the test sample during a 24-hour soak.

Charge / mass ratio:

The bound charge per gram of polymer in a latex was determined by conductomeric titration after the water-soluble ionic materials were removed. If there is a sufficient amount of tied charge, the latex can be centrifuged, often after adding, for example, 3% (based on the latex solids content) carbon tetrachloride, and the serum phase is separated and the remaining solids are then washed and vigorously washed Stir again dispersed in water. Conductometric titration is performed on the dispersed solids as well. Ion exchange methods can also be used to remove the ionic water-soluble materials from the latex types that have sufficient bound charges to remain stable until the conductometric titration is complete. For latex types that have insufficient bound charge levels to remain stable, small amounts of non-ionic surfactants can be added before the ion exchange treatment.

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Claims (11)

640 026 1. A process for producing a sheet, characterized in that the following steps are carried out: (I) preparation of an aqueous dispersion which contains 1-30% by weight, based on the total dry weight, of water-dispersible fibers, (II) mixing this dispersion with: (A) 60-95% by weight, based on the total dry weight of at least one finely divided, essentially water-insoluble, non-fibrous inorganic filler and (B) 2 to 30% by weight, based on the total dry weight, of a binder which contains at least one film-forming water-insoluble organic polymer material in the form of an ionically stabilized latex, which does not contain more than 0.7 milliequivalents of bound charge per gram of the polymer in the latex contains (III) colloidally destabilizing the mixture obtained by mixing the product of steps (I) and (II) with a sufficient amount of a water-soluble or water-dispersible ionic material or a polymer having a charge which is equal to that of the ionic stabilization the latex is opposed to form a fibrous agglomerate in aqueous suspension, (IV) distribution and dewatering of the aqueous suspension on a porous support to form a wet fleece, and (V) drying the fleece, and the ionically stabilized latex lacking a non-ionic stabilization sufficient to impair the formation of a fiber agglomerate. 2. The method according to claim 1, characterized in that the colloidal destabilization step forms a fiber agglomerate in aqueous suspension, with the property that the suspension at a concentration of 100 g solids in 13500 ml for a period of 4 seconds to 120 seconds in a 25 , 4 x 30.5 cm Williams standard foil mold with a 5.1 cm outlet and a 76.2 cm water pipe branch, which is equipped with a 0.149 mm stainless steel sieve with a wire diameter of 0.0114 cm is provided, so dewatered that at least 85% of the total solids of the fiber agglomerate, which contain at least 60% of the fillers, remain in the moist tissue during dewatering according to stage (IV). 2nd PATENT CLAIMS 3. The method according to claim 1, characterized in that the aqueous dispersion of the fibers has a liquor ratio of 0.1 to 6 wt .-%, based on the total dry weight. 4. The method according to any one of claims 1, 2 or 3, characterized in that the fiber content is 5-10 wt .-%, based on the total dry weight. 5. The method according to any one of claims 1 to 4, characterized in that the latex fraction of 5-15 wt .-%, based on the total dry weight. 6. The method according to any one of claims 1 to 5, characterized in that the proportion of the filling material is 70-90% by weight, based on the dry weight. 7. The method according to any one of claims 1 to 6, characterized in that the latex material contains copolymerized styrene and butadiene. 8. The method according to any one of claims 1 to 7, characterized in that the latex material contains a copolymer of an ethylenically unsaturated carboxylic acid. 9. The method according to any one of claims 1 to 8, characterized in that the draining time is between 15 and 60 seconds. 10. The method according to any one of claims 1 to 9, characterized in that the organic polymer material contains a bound charge in the range of 0.03 to 0.4 milliequivalents per gram of the polymer in the latex. 11. Self-supporting sheet separated from water, produced by the process according to claim 1, which is a composition of: (A) 1-30% by weight, based on the total dry weight of water-dispersible fibers, (B) 2-30% by weight, based on the total dry weight of at least one film-forming water-insoluble organic polymer which does not contain more than 0.7 milliequivalents of bound charge per gram of polymer, and (C) 60-95% by weight, based on the total dry weight, of at least one finely divided, essentially water-insoluble, non-fibrous inorganic filler.