Calcium carbonate-containing composite

Abstract

The present invention relates to a process for producing a composite of calcium carbonate particles, preferably having an average primary particle size, determined by observation with an electron microscope, of greater than 200 nm, which adhere to the surface of at least one fibre, the composite having a specific surface area of less than 30 m2 / g, preferably less than 9 m2 / g, preferably in the range from 1 to 8 m2 / g, in particular in the range from 2 to 7 m2 / g, wherein a weight ratio between the calcium carbonate particles and the at least one fibre is 5:95 to 95:5, comprising the synthesis of calcium carbonate in a reaction vessel using a carbonisation process, wherein (1) an aqueous suspension containing the at least one fibre is provided, (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added, and (3) a gas containing carbon dioxide is introduced into the reaction vessel. The present invention further relates to a composite of calcium carbonate particles and at least one fibre, wherein the calcium carbonate particles preferably have an average primary particle size, determined by observation with an electron microscope, of greater than 200 nm, wherein the weight ratio between the calcium carbonate particles and the fibre is 5:95 to 95:5, wherein the composite has a specific surface area of less than 30 m2 / g, advantageously less than 20 m2 / g, preferably less than 9 m2 / g, preferably in the range from 1 to 8 m2 / g, in particular in the range from 2 to 7 m2 / g, and wherein the composite can be obtained by the process according to the invention. The present invention further relates to a product comprising the composite according to the invention.

Description

[0001] Composite containing calcium carbonate

[0002] The present invention relates to a calcium carbonate-containing composite, a method for its production and its use.

[0003] Composites containing calcium carbonate are already known. Calcium carbonate is used in particular as a mineral filler in various industrial applications, for example in papers, paints, varnishes, plasters, plastics and carpet backings.

[0004] Composites comprising calcium carbonate and at least one fiber have also been described.

[0005] WO 2021 / 191 277 A1 concerns a wrapping paper for smoking products containing cellulose fibers loaded with filler particles, which give the paper particularly favorable properties. In particular, the ash of a smoking product made from this wrapping paper has a better appearance.

[0006] More precisely, WO 2021 / 191 277 A1 discloses a wrapping paper for smoking articles comprising cellulose fibers loaded with calcium carbonate particles, wherein the mass of the cellulose fibers loaded with calcium carbonate particles is at least 1% of the mass of the wrapping paper and the calcium carbonate particles in the cellulose fibers loaded with calcium carbonate particles constitute at least 5% and at most 80% of the mass of the cellulose fibers loaded with calcium carbonate particles.

[0007] However, the publication provides no information on the production of the calcium carbonate particles or on the specific surface area of ​​the materials. More detailed information about the calcium carbonate particles is also lacking.

[0008] Accordingly, composites according to the present invention are not described in the publication. Furthermore, the publication also does not contain any information on properties that are of particular interest within the scope of the present invention (specific volume, apparent sheet density, breaking strength index MD, elongation at break MD, TEA index MD, tensile strength index (Elmendorf), 2-point flexural stiffness, strip puncture resistance (SCT index), air permeability P, air permeability Gurley, whiteness D65 OS, opacity C / 2). EP 3 127 868 B1 relates to complexes of calcium carbonate microparticles and fibers and processes for their production.In particular, EP 3 127 868 B1 relates to complexes comprising calcium carbonate microparticles with an average primary particle size of 10 nm or more and 200 nm or less, which adhere to the surface of a fiber and have a weight ratio between the calcium carbonate particles and the fiber of 5:95 to 95:5, and methods for their production.

[0009] More precisely, EP 3 127 868 B1 discloses a process for producing a complex of calcium carbonate particles with a mean primary particle size, determined by observation with an electron microscope, of 10 nm or more and 200 nm or less, adhering to the surface of a fiber, and wherein a weight ratio between the calcium carbonate particles and the fiber is 5:95 to 95:5, comprising the synthesis of calcium carbonate in a reaction vessel using a carbonation process, wherein the synthesis takes place in a solution containing the fiber while a liquid is injected into the reaction vessel, wherein the liquid comprises an aqueous suspension of slaked lime and the calcium carbonate is synthesized by reacting the aqueous suspension of slaked lime with a carbon dioxide-containing gas injected into the reaction vessel;o the liquid is injected with a jet flow velocity in the range of 1 m / s or more and 200 m / s or less; o the pressure in the reaction vessel is 0.05 MPa or more and 0.9 MPa or less, expressed as static pressure; o the pressure of the liquid to be injected is 0.01 MPa or more and 30 MPa or less.;

[0010] Possible applications of the complex thus obtained include a sheet, a paper containing the complex as a filler, a coating containing the complex, and a resin mixture obtained by mixing the complex with a resin. Investigations are also being conducted on materials containing calcium carbonate particles with a mean primary particle size, determined by electron microscopy, greater than 200 nm, adhering to the surface of a fiber, and on materials with an apparent sheet density of less than 0.60 g / cm³. 3and an opacity C / 2 greater than 84.2% cannot be inferred from the printed document.

[0011] In one example (Experiment 4), papers containing the following fillers are examined in more detail: (1) a complex of previously produced CV-treated pulp / calcium carbonate

[0012] (2) precipitated calcium carbonate microparticles (average particle size: approx.

[0013] 100 nm)

[0014] (3) Precipitated calcium carbonate (average particle size: approx. 3.5 pm). For the precipitated calcium carbonate (2), the analysis of the resulting calcium carbonate microparticles showed that they have a specific surface area BET of 31.6 m². 2 / g and exhibited an oil absorption of 126 ml / 100 g. Indications that this calcium carbonate was produced in a reaction vessel using a carbonation process, wherein

[0015] (1) an aqueous suspension containing at least one fiber was presented,

[0016] (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime was added and

[0017] (3) However, no information will be given if a carbon dioxide-containing gas has been introduced into the reaction vessel.

[0018] Information on the specific surface area BET of the calcium carbonate of complex (1) or of the precipitated calcium carbonate (3) cannot be found in the publication.

[0019] Accordingly, composites according to the present invention are not described in the publication. Furthermore, the publication also does not contain any information on properties that are of particular interest within the scope of the present invention (breaking strength index MD, elongation at break MD, TEA index MD, tensile strength index (Elmendorf), 2-point flexural stiffness, strip puncture resistance (SCT index), air permeability P, air permeability Gurley, whiteness D65 OS).

[0020] EP 3 127 867 A1 relates to calcium carbonate microparticles and processes for their production. This patent application relates in particular to processes for the production of calcium carbonates with a small particle size and an average primary particle size of less than 1 pm.

[0021] In this context, a process for the production of calcium carbonate particles with an average primary particle size of less than 1 pm is disclosed, which includes the synthesis of calcium carbonate with simultaneous injection of a liquid into a reaction vessel.

[0022] It is explained that the complexes obtained by the process can be used for various applications and that they can be widely used for all applications, including, for example, papers, fibers, cellulose composites, filter materials, coating paints, plastics and other resins, rubber, elastomers, ceramics, glass, tires, building materials (asphalt, asbestos, cement, slabs, concrete, bricks, tiles, plywood, fiberboard, and the like), various carriers (catalyst carriers, drug carriers, agrochemical carriers, microbial carriers, and the like), adsorbents (decontaminants, deodorants, dehumidifiers, and the like), anti-wrinkle agents, clay, abrasives, modifiers, repair materials, thermal insulation materials, damp-proofing materials, water-repellent materials, sealing materials, light-blocking materials, sealants, shielding materials, insect repellents, adhesives, inks, and cosmetics.Medical materials, paste materials, and the like. They can also be used for various fillers, coating agents, and the like in the applications mentioned above. Among other things, the calcium carbonate of this patent application is readily used for papermaking purposes, including, for example, printing papers, newsprint, inkjet printing papers, PPC papers, kraft papers, wood-free papers, coated papers, coated fine papers, gift wrap, thin papers, colored wood-free papers, cast-coated papers, carbonless copy papers, label papers, heat-sensitive papers, various fancy papers, water-soluble papers, release papers, process papers, hanging base papers, non-combustible papers, flame-retardant papers, base papers for laminated cardboard, battery separators, cushion papers, tracing papers, impregnated papers, papers for ODP, construction papers,Papers for decorative building materials, envelope papers, papers for ribbons, heat exchanger papers, chemical fiber papers, aseptic papers, water-resistant papers, oil-resistant papers, heat-resistant papers, photocatalytic papers, cosmetic papers (face blotting papers and the like), various hygiene papers (toilet papers, facial tissues, wipes, diapers, menstrual products and the like), cigarette rolling papers, cardboard (backing papers, corrugated cardboard, white cardboard and the like), raw papers for paper plates, cup papers, baking papers, sandpaper, synthetic papers and the like.

[0023] However, this patent application does not provide a definition of the complexes, nor does it describe any methods for producing the complexes.

[0024] The examples demonstrate various methods for the synthesis of calcium carbonate microparticles; the adhesion of the calcium carbonate microparticles to cellulose fibers was evaluated by simply mixing the fibers and the calcium carbonate; papers containing calcium carbonate microparticles as internal additives were produced and tested by mixing calcium carbonate with a cellulose slurry, and coated papers were produced using a pigment slurry that included the calcium carbonate microparticles.

[0025] However, this patent application does not describe a method for producing a composite from calcium carbonate particles, wherein the calcium carbonate particles adhere to the surface of at least one fiber, and wherein the composite has a specific surface area of ​​less than 30 m². 2 / g and wherein a weight ratio between the calcium carbonate particles and the at least one fiber is 5:95 to 95:5, wherein the process comprises the synthesis of calcium carbonate in a reaction vessel using a carbonation process, wherein

[0026] (1) an aqueous suspension is presented which contains at least one fiber,

[0027] (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added and

[0028] (3) a carbon dioxide-containing gas is introduced into the reaction vessel.

[0029] US 9,775,377 B2 relates to a wrapping material for tobacco products consisting of composite particles based on mineral particles, a method for its manufacture, and its use in

[0030] Tobacco products. One focus of this patent is on tobacco products with controlled burning properties.

[0031] A coating material for tobacco products is disclosed, consisting of composite particles obtained by a process comprising: a) preparing an aqueous suspension containing calcium carbonate particles; and b) adding a metal salt to the aqueous suspension, wherein the metal salt comprises at least one of aluminum nitrate, polyaluminum chloride, and aluminum nitrate sulfate, and further wherein the metal salt: i) forms a metallic base component in the suspension; and ii) has a solubility of more than 9.0 mg / L in water, as measured by the pH of the prepared suspension and at a temperature of 20°C. US 10,737940 B2 relates to complexes of calcium phosphate microparticles and fibers and processes for their preparation.In particular, this patent relates to complexes comprising calcium phosphate microparticles with an average primary particle size of 5 pm or less, which adhere to the surface of a fiber, and methods for their production.

[0032] A process for producing a complex comprising calcium phosphate particles with an average primary particle size of 5 pm or less, adhering to the surface of a fiber, is described, the process comprising:

[0033] Synthesis of a calcium carbonate in a solution containing a fiber to obtain a complex of calcium carbonate particles with an average primary particle size of less than 5 pm and the fiber; and reaction of the complex of calcium carbonate particles with phosphoric acid to obtain a complex of a calcium phosphate and the fiber; wherein the proportion of phosphoric acid is 10 to 100%, based on the solid content of calcium carbonate; wherein 15% or more of the surface of the fiber is covered by the calcium phosphate.

[0034] Against this background, the present invention was based on the objective of demonstrating possibilities for providing a calcium carbonate-containing composite with improved properties.In particular, improved additives were desired for all applications, including, for example, papers, fibers, cellulose composites, filter materials or membranes, coating paints, plastics and other resins, rubber, elastomers, ceramics, glass, tires, building materials, various carriers, adsorbents, anti-wrinkle agents, clay, abrasives, modifiers, rheology additives, repair materials, thermal insulation materials, moisture barrier materials, water-repellent materials, sealing materials, light-blocking materials, sealants, shielding materials, insect repellents, adhesives, inks, cosmetics, medical materials, tableting agents, food products, food packaging, agricultural films, paste materials, cardboard, raw papers for paper plates, cup papers, baking papers, sandpaper, synthetic papers, and the like. Furthermore, ways to provide papers with improved properties were sought.In this context, the following properties were particularly sought: specific volume preferably greater than 1.70 g / cm³. 3 , especially preferred greater than 1.84 g / cm³ 3 , especially greater than 1.86 g / cm³ 3 , with larger values ​​being particularly preferred; apparent leaf density preferably less than 0.60 g / cm³ 3 , especially those smaller than 0.58 g / cm³ 3 , especially less than 0.55 g / cm³ 3, with smaller values ​​being particularly preferred; breaking strength index MD preferably greater than 8.6 Nm / g, particularly preferably greater than 11.0 Nm / g, particularly greater than 15.0 Nm / g, with larger values ​​being particularly preferred; elongation at break MD preferably greater than 0.53%, particularly preferably greater than 0.70%, particularly greater than 0.77%, with larger values ​​being particularly preferred; TEA index MD preferably greater than 27 J / kg, particularly preferably greater than 50 J / kg, particularly greater than 70 J / kg, with larger values ​​being particularly preferred; tensile strength index (Elmendorf) preferably greater than 1.30 mNm / g, particularly preferably greater than 1.60 mNm / g, particularly greater than 1.69 mNm / g, with larger values ​​being particularly preferred; 2-point flexural stiffness preferably greater than 0.30 Nm, particularly preferably greater than 0.40 Nm, particularly greater than 0.44 Nm, with larger values ​​being particularly preferred;Strip puncture resistance (SCT index) preferably greater than 6.7 Nm / g, particularly preferably greater than 9.3 Nm / g, particularly greater than 10.2 Nm / g, with larger values ​​being particularly preferred; air permeability P preferably greater than 40.0 pm / Pa*s, particularly preferably greater than 62.4 pm / Pa*s, particularly greater than 80.0 pm / Pa*s, with larger values ​​being particularly preferred; air permeability Gurley preferably less than 4.00 s / 100 ml, particularly preferably less than 2.20 s / 100 ml, particularly less than 1.57 s / 100 ml, with smaller values ​​being particularly preferred; whiteness D65 OS preferably greater than 88.9%, particularly preferably greater than 89.1%, particularly greater than 90.0%, with larger values ​​being particularly preferred; and / or o opacity C / 2 preferably greater than 84.2%, particularly preferably greater than 85.1%, particularly greater than 86.0%, with larger values ​​being particularly preferred.;

[0035] Furthermore, there is a desire for ways to improve polymers, especially bioplastics. The primary goal is to improve the mechanical properties of polymers, particularly polylactic acid. Specifically, an improved modulus of elasticity is required, which can be of particular interest in improving impact strength and notched impact strength.

[0036] These and other unspecified problems, which can be directly derived from the above context, are solved by providing a composite with all the features of claim 1. The dependent claims referring back to claim 1 describe particularly advantageous variants of the composite. The use claim relates to a particularly advantageous application of the composite according to the invention.

[0037] By providing a composite of calcium carbonate particles, preferably with a mean primary particle size, determined by observation with an electron microscope, of greater than 200 nm, and at least one fiber, wherein the calcium carbonate particles adhere to the surface of the at least one fiber, wherein the composite has a specific surface area of ​​less than 30 m² 2 / g, preferably less than 20 m 2 / g, preferably less than 9 m 2 / g, preferably in the range of 1 to 8 m 2 / g, especially in the range of 2 to 7 m 2 / g, wherein the weight ratio between the calcium carbonate particles and the fiber is 5:95 to 95:5 and wherein the composite is obtainable by a process comprising the synthesis of calcium carbonate in a reaction vessel using a carbonation process, wherein

[0038] (1) an aqueous suspension is presented which contains at least one fiber,

[0039] (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added and

[0040] (3) When a carbon dioxide-containing gas is introduced into the reaction vessel, it is possible, in a manner not readily predictable, to make accessible a calcium carbonate-containing composite with improved properties, which is particularly suitable as an additive for all applications, including, for example, papers, fibers, cellulose composites, filter materials or membranes, coating paints, plastics and other resins, rubber, elastomers, ceramics, glass, tires, building materials, various carriers, adsorbents, anti-wrinkle agents, clay, abrasives, modifiers, rheology additives, repair materials, thermal insulation materials, moisture barrier materials, water-repellent materials, sealing materials, light-blocking materials, sealants, shielding materials, insect repellents, adhesives, inks, cosmetics, medical materials, tableting agents, foodstuffs, food packaging, agricultural films, paste materials, cardboard,This paper is ideally suited for use in raw papers for paper plates, cup papers, baking papers, sandpaper, synthetic papers, and the like. It demonstrates possibilities for providing papers with improved properties. In particular, the following properties are achieved: o specific volume preferably greater than 1.70 g / cm³, 3 , especially preferred greater than 1.84 g / cm³ 3 , especially greater than 1.86 g / cm³ 3 , with larger values ​​being particularly preferred; o apparent leaf density preferably less than 0.60 g / cm³ 3 , especially those smaller than 0.58 g / cm³ 3 , especially less than 0.55 g / cm³ 3, with smaller values ​​being particularly preferred; o Fracture strength index MD preferably greater than 8.6 Nm / g, particularly preferably greater than 11.0 Nm / g, particularly greater than 15.0 Nm / g, with larger values ​​being particularly preferred; o Elongation at break MD preferably greater than 0.53%, particularly preferably greater than 0.70%, particularly greater than 0.77%, with larger values ​​being particularly preferred; o TEA index MD preferably greater than 27 J / kg, particularly preferably greater than 50 J / kg, particularly greater than 70 J / kg, with larger values ​​being particularly preferred; o Tear strength index (Elmendorf) preferably greater than 1.30 mNm / g, particularly preferably greater than 1.60 mNm / g, particularly greater than 1.69 mNm / g, with larger values ​​being particularly preferred; o 2-point bending stiffness preferably greater than 0.30 Nm, particularly preferably greater than 0.40 Nm, particularly greater than 0.44 Nm, with larger values ​​being particularly preferred;o Strip puncture resistance (SCT index) preferably less than 20.4 Nm / g, particularly preferably less than 16.1 Nm / g, particularly less than 12.6 Nm / g, with smaller values ​​being particularly preferred; o Air permeability P preferably greater than 40.0 pm / Pa*s, particularly preferably greater than 62.4 pm / Pa*s, particularly greater than 80.0 pm / Pa*s, with larger values ​​being particularly preferred; o Air permeability Gurley preferably less than 4.00 s / 100 ml, particularly preferably less than 2.20 s / 100 ml, particularly less than 1.57 s / 100 ml, with smaller values ​​being particularly preferred; o Whiteness D65 OS preferably greater than 88.9%, particularly preferably greater than 89.1%, particularly greater than 90.0%, with larger values ​​being particularly preferred; and / or o opacity C / 2 preferably greater than 84.2%, particularly preferably greater than 85.1%, particularly greater than 86.0%, with larger values ​​being particularly preferred.;

[0041] Furthermore, the composite according to the invention is particularly suitable for applications in polymers, especially in bioplastics.

[0042] This paper presents methods for producing polylactic acid and composite compounds with improved mechanical properties. In particular, it demonstrates the achievement of compounds with an enhanced modulus of elasticity, which can be of particular interest for improving the impact strength or notched impact strength of the compounds.

[0043] The present invention relates accordingly to a method for producing a composite of calcium carbonate particles, preferably with an average primary particle size, determined by observation with an electron microscope, of greater than 200 nm, which adhere to the surface of at least one fiber, wherein the composite has a specific surface area of ​​less than 30 m². 2 / g, preferably less than 20 m 2 / g, preferably less than 9 m2 / g, preferably in the range of 1 to 8 m 2 / g, especially in the range of 2 to 7 m 2 / g, and wherein the weight ratio between the calcium carbonate particles and the at least one fiber is 5:95 to 95:5.

[0044] In the context of the present invention, the calcium carbonate particles of the composite preferably comprise precipitated calcium carbonate. The shape of the preferably precipitated calcium carbonate particles is not subject to any further restrictions and can be tailored to the specific application. However, scalenohedral, rhombohedral, needle-shaped, plate-shaped, or spherical particles are preferred. In a particularly preferred embodiment of the present invention, spherical precipitated calcium carbonate particles are used, since these typically exhibit an isotropic property profile. Accordingly, the resulting composites are also advantageously characterized by a property profile that is as isotropic as possible.

[0045] The aspect ratio of the preferably precipitated calcium carbonate particles is preferably less than 5, preferably less than 4, particularly preferably less than 3, advantageously less than 2, even more preferably less than 1.5, most preferably in the range of 1.0 to 1.25, preferably less than 1.1, particularly less than 1.05.

[0046] The aspect ratio of the preferably precipitated calcium carbonate particles, in this context, refers to the quotient of the maximum and minimum particle diameters. It is preferably determined as a mean value (number-average) using electron microscopy. For spherical, preferably precipitated calcium carbonate particles, only particles with a size in the range of 0.1 pm to 30.0 pm are preferably considered. For rhombohedral, preferably precipitated calcium carbonate particles, only particles with a size in the range of 0.1 pm to 20.0 pm are preferably considered. For other, preferably precipitated calcium carbonate particles, only particles with a size in the range of 0.1 pm to 2.0 pm are preferably considered.

[0047] Furthermore, preferably at least 90%, and more favorably at least 95%, of all particles have an aspect ratio of less than 5, more preferably less than 4, more preferably less than 3, more favorably less than 2, more preferably less than 1.5, and most preferably in the range of 1.0 to 1.25, more preferably less than 1.1, and more favorably less than 1.05.

[0048] Particularly advantageous are spherical, preferably precipitated calcium carbonate particles, which preferably exist predominantly as single particles. Minor deviations from a perfect spherical shape are acceptable as long as the properties of the particles are not fundamentally altered. Thus, the surface of the particles may exhibit occasional defects or additional deposits.

[0049] In a particularly preferred embodiment of the present invention, the preferably precipitated calcium carbonate particles are preferably spherical and essentially amorphous. The term "amorphous" here refers to those calcium carbonate modifications in which the atoms do not form ordered structures, at least partially, but rather an irregular pattern, and therefore only possess short-range order, but not long-range order. These are to be distinguished from crystalline modifications of the calcium salt, such as calcite, vaterite, and aragonite, in which the atoms exhibit both short-range and long-range order. However, in this preferred embodiment of the present invention, the presence of crystalline components is not categorically excluded. Preferably, the proportion of crystalline calcium carbonate is less than 50 wt.%, particularly preferably less than 30 wt.%, and most preferably less than 15 wt.%.-%, in particular less than 10 wt.%. In a particularly preferred embodiment of the present invention, the proportion of crystalline calcium carbonate is less than 8.0 wt.%, preferably less than 6.0 wt.%, expediently less than 4.0 wt.%, particularly preferably less than 2.0 wt.%, most preferably less than 1.0 wt.%, in particular less than 0.5 wt.%, in each case based on the total weight of the calcium carbonate.

[0050] X-ray diffraction with an internal standard, preferably quartz, in conjunction with Rietveld refinement has proven particularly effective for determining the amorphous and crystalline components.

[0051] In this preferred embodiment of the present invention, the calcium carbonate particles, preferably the amorphous calcium carbonate particles, are advantageously stabilized by at least one substance, in particular at least one surfactant, which is preferably arranged on the surface of the calcium carbonate particles, especially on the surface of the preferably spherical calcium carbonate particles. For the purposes of the present invention, "surfactants" expediently refer to organic compounds that strongly accumulate at interfaces (water / calcium carbonate particles) when dissolved and thereby reduce the surface tension, preferably measured at 25°C. For further details, reference is made to the technical literature, in particular to Römpp-Lexikon Chemie / Ed. Jürgen Falbe; Manfred Regitz. Rev. by Eckard Amelingmeier; Stuttgart, New York; Thieme; Volume 2: Cm-G; 10.Edition (1997); keyword: “surface-active substances”, referred to.

[0052] Preferably the substance, in particular the surfactant, has a molar mass greater than 100 g / mol, preferably greater than 125 g / mol, in particular greater than 150 g / mol, and conforms to the formula R-Xn.

[0053] The term R represents a residue comprising at least 1, preferably at least 2, preferably at least 4, particularly preferably at least 6, and especially at least 8, carbon atoms, preferably an aliphatic or cycloaliphatic residue, which may optionally include further residues X and may optionally have one or more ether linkages. The term X represents a group comprising at least one oxygen atom and at least one carbon atom, sulfur atom, phosphorus atom, and / or nitrogen atom, preferably at least one phosphorus atom and / or at least one carbon atom. The following groups are particularly preferred: carboxylic acid groups ~COOH, carboxylate groups ~COO', sulfonic acid groups ~SO3H, sulfonate groups ~SO3', hydrogen sulfate groups -OSOsH, sulfate groups ~OSO3', phosphonic acid groups -PO3H2, phosphonate groups -POsH', ~PO3 2 ', Amino groups ~NR 1 R 2 as well as ammonium groups ~N + R 1 R 2 R3 , in particular carboxylic acid groups, carboxylate groups, phosphonic acid groups and phosphonate groups.

[0054] The remains R 1 , R 2 and R 3 In this context, they independently represent hydrogen or an alkyl group with 1 to 5 carbon atoms. One of the residues R 1 , R 2 and R 3 It could also be a remainder R.

[0055] Preferred counterions for the aforementioned anions are metal cations, in particular alkali metal cations, preferably Na + and K + , as well as ammonium ions.

[0056] Preferred counterions for the aforementioned cations are hydroxyl ions, hydrogen carbonate ions, carbonate ions, hydrogen sulfate ions, sulfate ions, and halide ions, in particular chloride and bromide ions. n represents a preferably integer in the range of 1 to 20, more preferably in the range of 1 to 10, and particularly in the range of 1 to 5.

[0057] Substances particularly suitable for the purposes of the present invention include alkyl carboxylic acids, alkyl carboxylates, alkyl sulfonic acids, alkyl sulfonates, alkyl sulfates, alkyl ether sulfates with preferably 1 to 4 ethylene glycol ether units, fatty alcohol ethoxylates with preferably 2 to 20 ethylene glycol ether units, alkylphenol ethoxylates, optionally substituted alkylphosphonic acids, optionally substituted alkylphosphonates, sorbitan fatty acid esters, alkyl polyglucosides, N-methylglucamides, homo- and copolymers of acrylic acid as well as their corresponding salt forms and block copolymers.

[0058] A first group of particularly advantageous substances are, if applicable, substituted alkylphosphonic acids, especially amino-tri-(methylenephosphonic acid), 1-hydroxyethylene-(1,1-diphosphonic acid), ethylenediamine-tetra-(methylenephosphonic acid), hexamethylenediamine-tetra-(methylenephosphonic acid), diethylenetriamine-penta-(methylenephosphonic acid), and, if applicable, substituted alkylphosphonates, especially of the aforementioned acids. These compounds are known as multifunctional sequestrants for metal ions and stone inhibitors.

[0059] Furthermore, homo- and copolymers, preferably homopolymers, of acrylic acid and their corresponding salt forms have proven particularly effective, especially those with a weight average molecular weight in the range of 1,000 g / mol - 10,000 g / mol.

[0060] Furthermore, the use of block copolymers, preferably double hydrophilic block copolymers, especially polyethylene oxide or polypropylene oxide, is particularly advantageous.

[0061] The proportion of the preferably surfactant substances can, in principle, be freely chosen and specifically adjusted for the respective application. However, it is preferably in the range of 0.1 wt.% to 5.0 wt.%, and in particular in the range of 0.3 wt.% to 1.0 wt.%, based on the CaCOa content of the particles.

[0062] The production of the preferably spherical, preferably amorphous calcium carbonate particles can be carried out in a manner known per se, e.g. by hydrolysis of dialkyl carbonate or alkylene carbonate in a solution comprising calcium cations.

[0063] The production of non-stabilized, spherical calcium carbonate particles is described in detail, for example, in patent application WO 2008 / 122358, the disclosure of which, in particular with regard to especially advantageous variants of the production of such non-stabilized, spherical calcium carbonate particles, is hereby explicitly incorporated by reference. The hydrolysis of the dialkyl carbonate or the alkylene carbonate is advantageously carried out in the presence of a hydroxide.

[0064] For the purposes of the present invention, preferred substances comprising gallons are calcium halides, preferably CaCh₂, CaB₂, and in particular CaCh₂, as well as calcium hydroxide. In a first particularly preferred embodiment of the present invention, CaCh₂ is used. In a further particularly preferred embodiment of the present invention, Ca(OH)₂ is used.

[0065] In a first particularly preferred embodiment of the present invention, a dialkyl carbonate is used. Particularly suitable dialkyl carbonates comprise 3 to 20, preferably 3 to 9, carbon atoms, in particular dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, di-isopropyl carbonate, di-n-butyl carbonate, di-sec-butyl carbonate and di-tert-butyl carbonate, with dimethyl carbonate being particularly preferred in this context.

[0066] In a further particularly preferred embodiment of the present invention, an alkylene carbonate is reacted. Particularly suitable alkylene carbonates comprise 3 to 20, preferably 3 to 9, particularly preferably 3 to 6, carbon atoms and especially include compounds comprising a ring of 3 to 8, preferably 4 to 6, particularly 5, atoms, with preferably 2 oxygen atoms and the rest being carbon atoms. Propylene carbonate (4-methyl-1,3-dioxolane) has proven particularly suitable in this context.

[0067] Alkali metal hydroxides, especially NaOH, and calcium hydroxide have proven particularly suitable as hydroxides. In a first particularly preferred embodiment of the present invention, NaOH is used. In a further particularly preferred embodiment of the present invention, Ca(OH)₂ is used.

[0068] Furthermore, the molar ratio of Ca 2+, preferably of calcium chloride, to OH', preferably alkali metal hydroxide, in the reaction mixture preferably greater than 0.5 : 1 and particularly preferably in the range of >0.5 : 1 to 1 : 1 , especially in the range of 0.6 : 1 to 0.9 : 1 .

[0069] The molar ratio of Ca 2+ The ratio of calcium chloride to dialkyl carbonate and / or alkylene carbonate in the reaction mixture is preferably in the range of 0.9 : 1.5 to 1.1 : 1, and particularly preferably in the range of 0.95 : 1 to 1 : 0.95. In a particularly advantageous embodiment of the present invention, the dialkyl carbonate and / or the alkylene carbonate and the calcium chloride are combined. 2+ , especially calcium chloride, used in equimolar amounts.

[0070] In a first, particularly preferred embodiment of the present invention, Ca(OH)₂ is not used as the OH' source. The components for the reaction are advantageously used in the following concentrations: a) Ca2+ : >10 mmol / l to 50 mmol / l, preferably 15 mmol / l to

[0071] 45 mmol / l, in particular 17 mmol / l to 35 mmol / l; b) Dialkyl carbonate and / or

[0072] Alkylene carbonate: >10 mmol / l to 50 mmol / l, preferably 15 mmol / l to 45 mmol / l, in particular 17 mmol / l to 35 mmol / l; c) OH-: 20 mmol / l to 100 mmol / l, preferably 20 mmol / l to

[0073] 50 mmol / l, particularly preferably 25 mmol / l to 45 mmol / l, especially 28 mmol / l to 35 mmol / l.

[0074] The respective concentration values ​​refer to the concentrations of the mentioned components in the reaction mixture.

[0075] In a further particularly preferred embodiment of the present invention, Ca(OH)₂, preferably lime milk, especially saturated lime milk, is used as the OH' source. The components for the reaction are advantageously used in the following concentrations: a) Ca(OH)₂: >5 mmol / l to 25 mmol / l, preferably 7.5 mmol / l to

[0076] 22.5 mmol / l, in particular 8.5 mmol / l to 15.5 mmol / l; b) Dialkyl carbonate and / or

[0077] Alkylene carbonate: >5 mmol / l to 25 mmol / l, preferably 7.5 mmol / l to

[0078] 22.5 mmol / l, in particular 8.5 mmol / l to 15.5 mmol / l.

[0079] The respective concentration values ​​refer to the concentrations of the mentioned components in the reaction mixture.

[0080] The reaction of the components is preferably carried out at a temperature in the range of 15°C to 30°C. The specific size of the calcium carbonate particles can be controlled by supersaturation in a known manner.

[0081] Under the conditions mentioned above, the calcium carbonate particles precipitate out of the reaction mixture.

[0082] The stabilization of the preferably amorphous calcium carbonate particles is expediently achieved by adding the preferably surfactant to the reaction mixture.

[0083] This addition of the substance should only take place after the reaction to form the calcium carbonate particles has begun, i.e., only after the addition of the reactants, preferably at least 1 minute, more preferably at least 2 minutes, expediently at least 3 minutes, particularly preferably at least 4 minutes, and especially at least 5 minutes, after mixing the reactants. Furthermore, the timing of the addition should be chosen such that the preferably surfactant is added shortly before the end of the precipitation and as shortly as possible before the start of the conversion of the preferably amorphous calcium salt, in particular the amorphous calcium carbonate, into a crystalline modification, since this maximizes the yield and purity of the "stabilized, spherical, amorphous calcium salt particles".If the preferably surfactant is added earlier, a bimodal product is generally obtained, which, in addition to the desired stabilized, spherical, amorphous calcium carbonate particles, also includes ultrafine, amorphous calcium carbonate particles as a byproduct. If the preferably surfactant is added later, the transformation of the desired "stabilized calcium carbonate particles" into crystalline modifications begins.

[0084] For this reason, the preferably surfactant is preferably added at a pH of less than or equal to 11.5, more preferably less than or equal to 11.3, and particularly less than or equal to 11.0. Addition at a pH in the range of 11.5 to 10.0, preferably in the range of 11.3 to 10.5, and particularly in the range of 11.0 to 10.8, is especially advantageous, in each case measured at the reaction temperature, preferably at 25°C.

[0085] By drying, "calcium carbonate particles with low structural water content" are obtained from the "stabilized calcium carbonate particles". For the purposes of the present invention, the resulting calcium carbonate particles are preferably dried such that they have the desired residual water content. A method has proven particularly effective for this purpose in which the calcium carbonate particles are preferably first pre-dried at a temperature up to 150°C and then dried, preferably at a temperature in the range of above 150°C to 250°C, more preferably in the range of 170°C to 230°C, more preferably in the range of 180°C to 220°C, and particularly in the range of 190°C to 210°C. Drying is preferably carried out in a circulating air drying oven. The calcium carbonate particles are expediently dried for at least 3 hours, more preferably at least 6 hours, and more preferably at least 20 hours.

[0086] In a further particularly preferred embodiment of the present invention, the preferably precipitated calcium carbonate particles are substantially crystalline, particularly substantially calcitic. However, in this preferred embodiment of the present invention, the presence of other components, particularly amorphous ones, is not categorically excluded. Preferably, the proportion of other non-crystalline calcium carbonate modifications is less than 50 wt.%, particularly preferably less than 30 wt.%, most preferably less than 15 wt.%, and particularly less than 10 wt.%. Furthermore, the proportion of non-calcitic calcium carbonate modifications is preferably less than 50 wt.%, particularly preferably less than 30 wt.%, most preferably less than 15 wt.%, and particularly less than 10 wt.%.

[0087] The average diameter of the preferably precipitated calcium carbonate particles can, in principle, be freely chosen. It is preferably in the range of 0.05 pm to 30.0 pm, and particularly in the range of 0.1 pm to 15.0 pm.

[0088] For amorphous calcium carbonate particles, the mean diameter of the calcium carbonate particles is advantageously in the range of 0.05 pm to 2.0 pm, preferably less than 1.75 pm, particularly preferably less than 1.5 pm, and especially less than 1.2 pm. Furthermore, in this case, the mean particle diameter is advantageously greater than 0.1 pm, preferably greater than 0.2 pm, and especially greater than 0.3 pm.

[0089] For scalenohedral calcium carbonate particles, the mean diameter of the calcium carbonate particles is advantageously in the range of 0.05 pm to 2.0 pm, preferably less than 1.75 pm, particularly preferably less than 1.5 pm, and especially less than 1.2 pm. Furthermore, in this case, the mean particle diameter is advantageously greater than 0.1 pm, preferably greater than 0.2 pm, and especially greater than 0.3 pm.

[0090] Furthermore, scalenohedral calcium carbonate particles have also proven particularly suitable, preferably having a mean diameter in the range of 1.0 pm to 5.0 pm, preferably less than 4.5 pm, particularly preferably less than 4.0 pm, and especially less than 3.5 pm. In this case, the mean particle diameter is also preferably greater than 1.5 pm, preferably greater than 2.0 pm, and especially greater than 3.0 pm.

[0091] For rhombohedral calcium carbonate particles, the mean diameter of the calcium carbonate particles is advantageously in the range of 0.05 pm to 2.0 pm, preferably less than 1.75 pm, particularly preferably less than 1.5 pm, and especially less than 1.2 pm. Furthermore, in this case, the mean particle diameter is advantageously greater than 0.1 pm, preferably greater than 0.2 pm, and especially greater than 0.3 pm.

[0092] Furthermore, rhombohedral calcium carbonate particles have also proven particularly suitable, preferably having a mean diameter in the range of 1.0 pm to 20.0 pm, preferably less than 18.0 pm, particularly preferably less than 16.0 pm, and especially less than 14.0 pm. In this case, the mean particle diameter is also preferably greater than 2.5 pm, preferably greater than 4.0 pm, and especially greater than 6.0 pm.

[0093] For needle-shaped calcium carbonate particles, the mean diameter of the calcium carbonate particles is advantageously in the range of 0.05 pm to 2.0 pm, preferably less than 1.5 pm, particularly preferably less than 1.0 pm, and especially less than 0.75 pm. Furthermore, in this case, the mean particle diameter is advantageously greater than 0.1 pm, preferably greater than 0.2 pm, and especially greater than 0.3 pm.

[0094] For platelet-shaped calcium carbonate particles, the mean diameter of the calcium carbonate particles is advantageously in the range of 0.05 pm to 2.0 pm, preferably less than 1.75 pm, particularly preferably less than 1.5 pm, and especially less than 1.2 pm. Furthermore, in this case, the mean particle diameter is advantageously greater than 0.1 pm, preferably greater than 0.2 pm, and especially greater than 0.3 pm.

[0095] For spherulitic (spherical) calcium carbonate particles, a mean diameter in the range of 1.0 pm to 30.0 pm, preferably less than 20.0 pm, preferably less than 18.0 pm, particularly preferably less than 16.0 pm, and especially less than 14.0 pm, has proven particularly advantageous. Furthermore, in this case, the mean particle diameter is advantageously greater than 2.5 pm, preferably greater than 4.0 pm, and especially greater than 6.0 pm.

[0096] The form factor of the calcium carbonate particles, defined here as the quotient of minimum particle diameter and maximum particle diameter, is advantageously greater than 0.90 for at least 90%, preferably greater than 0.95, and more preferably greater than 0.95. In this context, for spherical calcium carbonate particles, preferably only particles with a size in the range of 0.1 pm to 30.0 pm are considered. For rhombohedral calcium carbonate particles, preferably only particles with a size in the range of 0.1 pm to 20.0 pm are considered. For other calcium carbonate particles, preferably only particles with a size in the range of 0.1 pm to 2.0 pm are considered.

[0097] The calcium carbonate particles are advantageously characterized by a comparatively low water content. Based on their total weight, they have a water content (residual moisture at 200°C) of at most 5.0 wt.%, preferably at most 2.5 wt.%, more preferably at most 1.0 wt.%, particularly preferably at most 0.5 wt.%, even more preferably less than 0.4 wt.%, expediently less than 0.3 wt.%, advantageously less than 0.2 wt.%, and in particular at most 0.1 wt.%.

[0098] Within the scope of the present invention, the water content of the calcium carbonate particles is preferably determined by thermogravimetry, wherein the measurement is preferably carried out under nitrogen (nitrogen flow rate preferably 20 ml / min) and expediently over the temperature range from 40°C or lower to 250°C or higher. Furthermore, the measurement is preferably carried out at a heating rate of 10°C / min.

[0099] When amorphous calcium carbonate particles are used in the present invention, they advantageously have a low structural water content. This content is preferably less than 5 mol, more preferably less than 3 mol, more preferably less than 1 mol, and more particularly less than 0.5 mol of structural water per mol of calcium carbonate. In a particularly preferred embodiment of the present invention, the amorphous calcium carbonate particles do not contain any structural water. The average particle size or shape, or the like, of the calcium carbonates forming part of the composites of the present invention can be identified by electron microscopic observation. Furthermore, calcium carbonate microparticles of different sizes or shapes can be used together with the fibers by controlling the conditions under which the calcium carbonate is synthesized.

[0100] Within the scope of the present invention, composites of calcium carbonate particles are produced in the presence of at least one fiber. The at least one fiber forming part of the composites is not subject to any particular limitations, and examples of fibers that can be used include, without limitation, not only natural fibers such as cellulose, but also synthetic fibers artificially synthesized from raw materials such as petroleum, regenerated fibers (semi-synthetic fibers) such as viscose and lyocell, and even inorganic fibers and the like. In addition to the examples mentioned above, natural fibers include protein fibers such as wool and silk yarns, and collagen fibers; complex carbohydrate fibers such as chitin-chitosan fibers and alginate fibers, and the like. Examples of cellulose-containing raw materials include pulp fibers (wood pulp and non-wood pulp) and bacterial cellulose, from which pulp can be produced by pulping wood raw materials.Examples of wood raw materials are softwoods such as Pinus densiflora, Pinus thunbergii, Abies Sachalinensis, Picea jezoensis, Pinus koraiensis, Larix kaempferi, Abies firma, Tsuga sieboldii, Cryptomeria aponica, Chamaecyparis obtusa, Larix kaempferi, Abies veitchii, Piceajezoensis var. hondoensis, Thujopsis dolabrata, Douglas fir (Pseudotsuga menziesii), hemlock (Conium maculatum), silver fir (Abies concolor), spruces, balsam fir (Abies balsamea), cedars, pines, Pinus merkusii, Pinus radiata and their mixed materials; and hardwoods such as Fagus crenata, birch, Ainus japonica, oak, Machilus thunbergii, Castanopsis, Betula platyphylla, Populus nigra var. italica, poplar, Fraxinus, Populus maximowiczii, eucalyptus, mangroves, meranti, acacia and their mixed materials.

[0101] The technology for pulping wood raw materials is not subject to any particular restrictions, and examples include pulping processes commonly used in the paper industry. Pulp can be classified according to the pulping process and includes, for example, chemical pulp, obtained by pulping using the Kraft process, sulfite process, soda process, polysulfide process, or the like; mechanical pulp, obtained by pulping with mechanical force, such as a refiner, grinding machine, or the like; semi-chemical pulp, obtained by pulping with mechanical force after chemical pretreatment; recycled paper pulp; decolorized pulp, and the like. Pulp can be used unbleached (before bleaching) or bleached (after bleaching).

[0102] Examples of non-wood pulps include cotton, hemp, sisal (Agave sisalana), abaca (Musa textilis), flax, straw, bamboo, bagas, kenaf and the like.

[0103] The cellulose fibers can be unblown or beaten, and the type can be selected depending on the properties of the complex materials, but beaten processing is preferred. This is expected to improve the strength of the products and promote the adhesion of calcium carbonate.

[0104] Synthetic fibers include polyesters, polyamides, polyolefins, and acrylic fibers; semi-synthetic fibers include viscose, acetate, and the like; and inorganic fibers include glass fibers, carbon fibers, various metal fibers, and the like.

[0105] The fibers mentioned above can be used alone or as a mixture of two or more of them. In particular, the composites preferably comprise a wood pulp or a combination of a wood pulp and a non-wood pulp and / or a synthetic fiber, most preferably a wood pulp alone.

[0106] In preferred embodiments, the at least one fiber forming part of the composites of the present invention is a cellulose fiber. Alternatively, fibrous materials collected from the wastewater of paper mills, for example, can be fed to the carbonation reaction of the present invention. Various composites, including those of different shapes, such as fibrous particles, can be synthesized by feeding such materials into the reaction vessel.

[0107] The composites according to the invention are typically characterized by a specific property profile of the remaining ash after ashing of the composite at 450°C. The following results are generally obtained from the remaining ash: (a) dso after SEM: greater than 150 nm, preferably greater than 200 nm, particularly preferably greater than 500 nm, especially 1 pm to 50 pm; and / or

[0108] (b) Specific surface area (BET): less than 9 g / m² 2 preferably in the range of 1 to 8 m 2 / g, especially in the range of 2 to 7 m 2 / g; preferably in the range of 1.25-6.0 g / m² 2 ; particularly preferred 1.5–5.0 g / m³ 2 ; in particular 2.0–4.5 g / m³ 2 ; and / or

[0109] (c) dso according to CILAS (laser diffraction?) greater than 1.0 pm, preferably greater than 1.5 pm, particularly preferably greater than 2.0 pm, in particular 2.2 pm to 10.0 pm; and / or

[0110] (d) dso according to Sedigraph: 1.0 pm, preferably greater than 1.5 pm, particularly preferably greater than 1.7 pm, especially 1.8 pm to 5.0 pm.

[0111] Furthermore, the composites obtained by the present invention can typically be used in combination with materials known as inorganic fillers, organic fillers, or various fibers.Examples of inorganic fillers include calcium carbonate (precipitated calcium carbonate, ground calcium carbonate), magnesium carbonate, barium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, clay (kaolin, calcined kaolin, delaminated kaolin), talc, zinc oxide, zinc stearate, titanium dioxide, silica-containing products made from sodium silicate and a mineral acid (white carbon, silicon dioxide / calcium carbonate complexes, silicon dioxide / titanium dioxide complexes), terra alba, bentonite, diatomaceous earth, calcium sulfate, zeolite, inorganic fillers recycled from ash obtained in a deinking process, and inorganic fillers consisting of complexes formed during the recycling process with silica or calcium carbonate, etc.In addition to calcium carbonate-silica complexes, such as calcium carbonate and / or precipitated calcium carbonate-silica complexes, amorphous silicas, such as white carbon, can also be used. Organic fillers include urea-formaldehyde resins, polystyrene resins, phenolic resins, microhollow particles, acrylamide complexes, wood-derived materials (microfibers, microfibril fibers, kenaf powder), modified / insoluble starches, ungelatinized starches, and the like. Fibers that can be used include not only natural fibers, such as cellulose, but also synthetic fibers artificially synthesized from raw materials such as petroleum, regenerated fibers (semi-synthetic fibers) such as viscose and lyocell, and even inorganic fibers and the like.In addition to the examples mentioned above, natural fibers include protein fibers, such as wool and silk yarns, and collagen fibers; complex carbohydrate fibers, such as chitin-chitosan fibers, and alginate fibers, and the like. Examples of cellulose-containing raw materials include pulp fibers (wood pulp and non-wood pulp) and bacterial cellulose, from which pulp can be produced by pulping wood raw materials. Examples of wood raw materials are coniferous trees, such as Pinus densiflora, Pinus thunbergii, Abies sachalinensis, Picea jezoensis, Pinus koraiensis, Larix kaempferi, Abies firma, Tsuga sieboldii, Cryptomeria japonica, Chamaecyparis obtusa, Larix kaempferi, Abies veitchii, and Picea jezoensis var.hondoensis, Thujopsis dolabrata, Douglas fir (Pseudotsuga menziesii), hemlock (Conium maculatum), silver fir (Abies concolor), spruce, balsam fir (Abies balsamea), cedar, pine, Pinus merkusii, Pinus radiata and their mixtures; and hardwoods such as Fagus crenata, birch, Ainus japonica, oak, Machilus thunbergii, Castanopsis, Betula platyphylla, Populus nigra var. italics, poplar, Fraxinus, Populus maximowiczii, eucalyptus, mangroves, Meranti, acacia and their mixtures. The technique for pulping the wood raw materials is not specifically limited and examples include pulping processes commonly used in the paper industry. Pulp can be classified according to the pulping method and includes, for example, chemical pulp, which is obtained by pulping using the Kraft process, sulfite process, soda process, polysulfide process or the like; mechanical pulp, which is obtained by pulping with a mechanical force, such as...a refiner, grinding machine, or the like; semi-chemical pulp, obtained by pulping with mechanical force after chemical pretreatment; recycled paper pulp; decolorized pulp, and the like. The pulps may have been unbleached (before bleaching) or bleached (after bleaching). Examples of non-wood pulps are cotton, hemp, sisal (Agave si-salana), abaca (Musa textilis), flax, straw, bamboo, bagas, kenaf, and the like. The pulps and non-pulps may be unbeaten or beaten. Synthetic fibers include polyesters, polyamides, polyolefins, and acrylic fibers; semi-synthetic fibers include viscose, acetate, and the like; and inorganic fibers include glass fibers, carbon fibers, various metal fibers, and the like. All of these may be used individually or in combination with two or more of them.

[0112] Within the scope of the present invention, the cellulose preferably has a fiber length of < 5 mm, particularly preferably < 3.5 mm, and especially < 1 mm.

[0113] The composite particles according to the invention are obtainable by a process in which

[0114] (1) an aqueous suspension containing at least one fiber is presented, (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added and

[0115] (3) a carbon dioxide-containing gas is introduced into the reaction vessel.

[0116] To produce calcium carbonate via the carbonation process, lime is typically used as the calcium source. This is achieved through a slaking step, in which water is added to quicklime (CaO) to obtain slaked lime (Ca(OH)₂), and a carbonation step, in which carbon dioxide gas (CO₂) is introduced into the slaked lime to yield calcium carbonate (CaCO₃). During this step, the slaked lime suspension, produced by adding water to quicklime, can be passed through a sieve to remove less soluble lime particles. Alternatively, slaked lime can also be used directly as the calcium source.

[0117] Reaction vessels preferably used for the production of calcium carbonate by the carbonation process (carbonation reactors: carbonators) include gas-injected carbonators and mechanically stirred carbonators. Gas-injected carbonators introduce carbon dioxide gas into a carbonation reaction vessel containing a suspension of slaked lime (milk of lime) to react the slaked lime with the carbon dioxide gas. Mechanically stirred carbonators are conveniently equipped with an internal stirrer that introduces carbon dioxide gas near the stirrer, causing the gas to form fine bubbles and thus improving the efficiency of the reaction between the slaked lime and the carbon dioxide gas.

[0118] Within the scope of the present invention, all conventional gassing containers typically suitable for gassing, gas dispersion or synthesis of calcium carbonate can generally be used.

[0119] In the context of the present invention, the aqueous solution comprises the calcium salt, based on its total weight, preferably 0.1 to 40 wt.%, particularly preferably 0.5 to 30 wt.%, even more preferably about 1 to 20 wt.%, of a calcium salt.

[0120] The aqueous suspension of slaked lime, based on its total weight, preferably has a solids content of 0.1 to 50 wt.%, particularly preferably 0.5 to 30 wt.%, and even more preferably about 1 to 20 wt.%. The aqueous suspension containing slaked lime that can be used includes those typically used for the synthesis of calcium carbonate and can be prepared, for example, by mixing slaked lime with water or by slaking (digestion) quicklime (calcium oxide) with water. The slaking conditions are not specifically limited but can, for example, include a CaO concentration of 0.1 wt.% or more, preferably 1 wt.% or more, and a temperature of 20°C to 100°C, preferably 30°C to 100°C.Furthermore, the average residence time in the quenching reaction vessel (slaker) is not subject to any particular limitations; for example, it can range from 5 minutes to 5 hours, preferably 2 hours or less. It should be understood that the quencher can be operated batchwise or continuously. It should be noted that the present invention can utilize a carbonation reaction vessel (carbonator) and a quenching reaction vessel (slaker) separately, or that a single reaction vessel can be used that serves as both a carbonation reaction vessel and a quenching reaction vessel.

[0121] In the present invention, water is used for the preparation of the suspension or for other purposes, and the water that can be used includes ordinary tap water, industrial water, groundwater, well water and the like, and also preferably includes ion-exchange water, distilled water, ultrapure water, industrial wastewater and water obtained during the separation / dehydration of the calcium carbonate slurry exiting from the carbonation step.

[0122] Furthermore, according to the present invention, the reaction mixture can circulate from the carbonation reaction vessel and be used as a liquid, preferably containing calcium hydroxide. Circulating the reaction solution in this way to increase the contact between the reaction solution and the carbon dioxide gas increases the reaction efficiency and the desired calcium carbonate can be readily obtained.

[0123] In the context of the present invention, a gas containing carbon dioxide (carbon dioxide gas) is introduced into the reaction vessel, where it is mixed with the reaction mixture. According to the present invention, the carbonation reaction can be carried out with good efficiency, since carbon dioxide gas can be supplied to the reaction mixture without a gas supply, such as a blower, fan, or the like, and the carbon dioxide gas is preferably finely dispersed by a liquid jet.

[0124] Within the scope of the present invention, the carbon dioxide concentration of the carbon dioxide-containing gas is not subject to any particular limitations. Furthermore, the amount of carbon dioxide gas introduced into the reactor is not subject to any particular limitations and can be selected accordingly. However, a flow rate of, for example, 100 to 10,000 l / h per kg of slaked lime is preferably used for the carbon dioxide gas.

[0125] The gas containing carbon dioxide according to the present invention can be essentially pure carbon dioxide gas or a mixture with another gas. For example, a gas containing an inert gas, such as air or nitrogen, in addition to carbon dioxide gas can be used as the carbon dioxide-containing gas. Furthermore, gases that can be used appropriately also include exhaust gases derived from combustion plants, coal-fired boilers, heavy oil boilers, and the like from paper mills. In addition, the carbonation reaction can also be carried out with carbon dioxide produced in calcination processes.

[0126] Various known excipients can also be added to the preparation of the composites of the present invention. For example, chelating agents can be added in the carbonation reaction, in particular polyhydroxy acids such as citric acid, malic acid, and tartaric acid; dicarboxylic acids such as oxalic acid; sugar acids such as gluconic acid; aminopolycarboxylic acids such as iminodeacetic acid and ethylenediaminetetraacetic acid, and their alkali metal salts; alkali metal salts of polyphosphoric acids such as hexametaphosphoric acid and tripolyphosphoric acid; amino acids such as glutamic acid and aspartic acid, and their alkali metal acids; ketones such as acetylacetone, methylacetoacetate, and allylacetoacetate; sugars such as sucrose; and polyols such as sorbitol.Surface treatment agents can also be added, such as saturated fatty acids like palmitic and stearic acid; unsaturated fatty acids like oleic and linoleic acid; resin acids like alicyclic carboxylic acids and abietic acid, as well as their salts, esters, and ethers; alcoholic activators, sorbitan fatty acid esters, amide- or amine-based surfactants, polyoxyalkylene alkyl ethers, polyoxyethylene nonyl phenyl ethers, sodium alpha-olefin sulfonate, long-chain alkyl amino acids, amine oxides, alkylamines, quaternary ammonium salts, aminocarboxylic acids, phosphonic acids, polycarboxylic acids, molten phosphoric acid, and the like. Dispersants can also be used upon request.Such dispersants include, for example, sodium polyacrylate, sucrose sulfites, glycerol sulfites, acrylic acid-maleic acid copolymer ammonium salts, methacrylic acid-naphthoxypolyethylene glycol acrylate copolymers, methacrylic acid-polyethylene glycol monomethacrylate copolymers, ammonium salts, polyethylene glycol monoacrylate, and the like. Furthermore, at least one water-soluble compound selected from the group consisting of H3PO4, K3PO4, KH2PO4, K2HPO4, Na2HPO4·12H2O, and (NH3)sPC·3H2O may be added. Calcium carbonate seed crystals may also be added.

[0127] These additives can be used alone or in combination with two or more of them. They can be added before or after the carbonation reaction. Such additives are preferably added in an amount of 0.001 wt.% to 20 wt.%, particularly preferably in an amount of 0.1 wt.% to 10 wt.%, based on the total amount of slaked lime.

[0128] In the present invention, the conditions of the carbonation reaction are not subject to any particular restrictions and can be selected according to the intended use. For example, the temperature of the carbonation reaction can be from 0°C to 90°C, preferably from 10°C to 70°C. The reaction temperature can be controlled by regulating the temperature of the reaction mixture with a temperature controller. However, if it exceeds 90°C, coarse calcium carbonate particles tend to multiply.

[0129] Furthermore, in the present invention, the carbonation reaction can be a batch reaction or a continuous reaction. Typically, the reaction is preferably carried out as a batch process, since residues after the carbonation reaction can be easily removed. The volume of the reaction is not specifically limited and can be 100 l or less or more than 100 l. The volume of the reaction vessel can, for example, be about 10 l to 100 l, or about 100 l to 50,000 l.

[0130] Furthermore, the carbonation reaction can be controlled by monitoring the pH of the reaction suspension and carried out until a pH value less than 9, preferably less than 8, and particularly preferably around 7, is reached, for example, depending on the pH profile of the reaction solution. Alternatively, the carbonation reaction can be controlled by monitoring the conductivity of the reaction solution. The carbonation reaction is preferably carried out until the conductivity drops to 1 mS / cm or less.

[0131] Furthermore, the carbonation reaction can also be controlled by the reaction time, and in particular by adjusting the duration for which the reactants remain in the reaction vessel. Additionally, in the present invention, the reaction can also be controlled by stirring the reaction solution in the carbonation reaction vessel or by carrying out the carbonation reaction as a multi-stage reaction.

[0132] In a particularly preferred embodiment of the present invention, the aqueous suspension in step (1) contains calcium carbonate seed particles. Preferably, in step (1), an aqueous suspension is provided which contains at least one fiber and a first quantity of at least one calcium salt, in particular slaked lime. This first quantity of at least one calcium salt is preferably reacted with a first quantity of a carbon dioxide-containing gas to form so-called calcium carbonate seed particles.

[0133] In step (2) preferably an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added to the aqueous suspension (1) which comprises at least one fiber and preferably calcium carbonate seed particles, and in step (3) a carbon dioxide-containing gas is introduced into the reaction vessel to synthesize further calcium carbonate.

[0134] Without the inventors wishing to be bound by this, it is assumed that the use of seed particles described above leads to the formation of larger calcium carbonate particles.

[0135] Advantageously, in step (1) an aqueous suspension is provided which contains the at least one fiber and, in each case based on the total amount of calcium salt or slaked lime added in step (2), 1 / 25 to 3 / 4 wt.%, preferably 1 / 23 to 3 / 5 wt.%, in particular 1 / 20 to 1 / 2, of the calcium salt, in particular of the slaked lime.

[0136] Furthermore, it has proven particularly advantageous to dose the aqueous solution of a calcium salt or the aqueous suspension of slaked lime in step (2) such that the pH value is maintained and controlled within a pH range of approximately 7–10 during fumigation. The carbon dioxide-containing gas to be used in step (3) preferably comprises 1% to 40%, more preferably 5% to 30%, particularly 10% to 20% CO₂ and 60% to 99%, more preferably 70% to 95%, particularly 80% to 90% N₂ and other gases other than CO₂. Furthermore, the carbon dioxide-containing gas is preferably supplied with a gas flow rate, based on the CO₂ gas flow rate, in the range of 0.1 to 50.0 dm³ / h. 3 CC / h / g CaO, preferably in the range of 2.5 to 35.0 dm 3 CO2 / h / g CaO, especially in the range of 5.0 to 25.0 dm 3 CO2 / h / g CaO was introduced into the reaction vessel.

[0137] Finally, the introduction of the carbon dioxide-containing gas into the reaction vessel is expediently carried out until the pH value of the aqueous suspension drops to 7.0 or less.

[0138] In the present invention, the composite according to the invention is obtained as a suspension, so that it can be stored in a storage tank or, depending on requirements, subjected to processing such as concentration, dehydration, drying, grinding, classification, aging, or dispersion. These processes can be achieved by known methods, which can be selected appropriately taking into account the purposes, energy efficiency, and the like. For example, the concentration / dehydration process is preferably carried out using a centrifugaldehyde generator, thickener, or the like. Examples of such centrifugaldehyde generators are decanters, screw carafes, and the like.If a filter or dehydrator is used, there are no special restrictions on its type, and any commonly used equipment may be employed, including, for example, pressure dryers such as filter presses, drum filters, belt presses, and tube presses, or vacuum drum filters such as Oliver filters or the like, which can be used appropriately to produce a calcium carbonate cake. Grinding equipment includes ball mills, sand mills, impact mills, high-pressure homogenizers, low-pressure homogenizers, test bench mills, ultrasonic mills, calender roller mills, abrasive mills, millstone mills, vibratory mills, mills, cutting mills, jet mills, crushers, beaters, single-screw extruders, twin-screw extruders, ultrasonic stirrers, home juicers / mixers, etc.Classifying agents include sieves such as meshes, outward- or inward-facing slotted or round-hole sieves, vibrating sieves, heavy soil cleaners, light soil cleaners, backwashers, sieve testers, and the like. Dispersing agents include high-speed dispersers, low-speed kneaders, and the like. The composites obtained by the present invention can be assembled as a suspension with fillers or pigments without being completely dehydrated, or can be dried to form a residue of retained substances or filter cake, or further processed into powder. The dryer used here is not subject to any particular restrictions; for example, airflow dryers, belt dryers, spray dryers, and the like can be used expediently.

[0139] The composites of the present invention can be used in particular to produce formed products. For example, the composites obtained by the present invention can be easily formed into sheets with a high ash content. Paper machines (sheet forming machines) used for sheet preparation include, for example, Fourdrinier machines, cylinder machines, slit formers, hybrid forming machines, multilayer paper machines, known sheet forming machines that combine the papermaking processes of these machines, and the like. Both the linear pressure in the press section of the paper machines and the linear calendering pressure in a subsequent optional calendering process can be selected within a range that is favorable for the runnability and performance of the complex sheets. Furthermore, the sheets thus formed can be impregnated or coated with starch, various polymers, pigments, and mixtures thereof.

[0140] During sheet forming, wet and / or dry strength additives (paper strength additives) can be added. This improves the strength of the products. Examples of strength additives include resins such as urea-formaldehyde resins, melamine-formaldehyde resins, polyamides, polyamines, epichlorohydrin resins, vegetable gums, latexes, polyethyleneimines, glyoxal, gums, mannogalactan polyethyleneimines, polyacrylamide resins, polyvinylamines, and polyvinyl alcohols; composite polymers or copolymers consisting of two or more components selected from the resins listed above; starches and processed starches; carboxymethylcellulose, guar gum, urea resins, and the like. There are no specific restrictions on the amount of strength additives that can be added.

[0141] Furthermore, high-molecular-weight polymers or inorganic materials can be added to promote the adhesion of fillers to fibers or to improve the retention of fillers or fibers. For example, coagulants can be added, in particular cationic polymers such as polyethyleneimines and modified polyethyleneimines containing a tertiary and / or quaternary ammonium group, polyalkyleneimines, dicyandiamide polymers, polyamines, polyamine / epichlorohydrin polymers, polymers of dialkyldiallylquaternary ammonium monomers, dialkylaminoalkyl acrylates, dialkylaminoalkyl methacrylates, dialkylaminoalkyl acrylamides and dialkylaminoalkyl methacrylamides with acrylamides, monoamine / epihalohydrin polymers, polyvinylamines and polymers containing a vinylamine moiety, as well as mixtures thereof; cation-rich biterionic polymers containing an anionic group, such as...A carboxyl or sulfone group copolymerized in the molecules of the polymers listed above; mixtures of a cationic polymer and an anionic or zwitterionic polymer, and the like. Cationic, anionic, or zwitterionic polyacrylamide-based materials can be used as retention aids.These can be used as retention systems, so-called dual polymers, in combination with at least one or more cationic or anionic polymers, or as multi-component retention systems in combination with at least one or more anionic inorganic microparticles, such as bentonite, colloidal silica, polysilicic acid, microgels made of polysilicic acid or polysilicic acid salts and aluminum-modified products thereof, or one or more organic microparticles with a particle size of 100 pm or less, wherein particularly preferred micropolymers consist of cross-linked / polymerized acrylamides. In particular, when the polyacrylamide-based materials, used alone or in combination with other materials, have a weight-average molecular weight of 2,000,000 Da or more, preferably 5,000,000 Da or more, and when the acrylamide-based materials expediently have a molecular weight of 10,000 Da.Good retention can be achieved with 000 Da or more and less than 30,000,000 Da, as determined by intrinsic viscosity measurement. Polyacrylamide-based materials can be emulsions or solutions. Specific compositions of such materials are not limited to those containing an acrylamide monomer unit as a structural element, but include, for example, copolymers of a quaternary ammonium salt of an acrylate ester and an acrylamide, or ammonium salts obtained by copolymerization of an acrylamide and an acrylate ester followed by quaternization of the copolymer. The cationic charge density of cationic polyacrylamide-based materials is not limited.Other additives, depending on the intended use, include opening enhancers, internal sizing agents, pH modifiers, defoamers, pitch control agents, slime suppressants, glowing salts, fillers, and inorganic particles (so-called bulking agents) such as calcium carbonate, kaolin, talc, and silica, among others. There are no specific limits on the quantity of these additives that may be used.

[0142] Shaping techniques other than sheet forming can also be used, and shaped products with various forms can be obtained through the so-called pulp forming process, in which a raw material is poured into a mold and then dewatered / dried by suction; or through the process in which a raw material is spread over the surface of a shaped product made of a resin, metal, or the like and dried, and then the dried material is removed from the substrate; or through other processes. Furthermore, the composites can be shaped like plastics by mixing them with resins, or like ceramics by calcining them with minerals such as silica or aluminum oxide. In the compounding, drying, and shaping steps shown above, either a single composite or a mixture of two or more composites can be used.Two or more composites can be used as a premix or mixed after being individually assembled, dried, and shaped.

[0143] Furthermore, various organic materials, such as polymers, or various inorganic materials, such as pigments, can be added later to shaped composite products.

[0144] Due to their excellent property profile, the composites according to the invention are also suitable as additives, particularly preferably as polymer additives, as additives or starting materials for the production of components, for shaping components prior to sintering processes, for applications in medical technology and / or microtechnology, and / or for the production of foamed objects. Particularly preferred medical technology applications preferably include resorbable implants.

[0145] As a polymer additive, the composites according to the invention are preferably added to at least one polymer, in particular a thermoplastic polymer, as a matrix polymer. Thermoplastic polymers, especially biopolymers, rubbers, in particular natural or synthetic rubbers, and / or polyurethanes are particularly preferred. In this context, the term "thermoplastic polymer" refers to a plastic that can be thermoplastically deformed within a specific temperature range, preferably between 25°C and 350°C. This process is reversible, meaning it can be repeated any number of times by cooling and reheating to the molten state, as long as the so-called thermal decomposition of the material does not occur due to overheating. This is what distinguishes thermoplastic polymers from thermosets and elastomers.

[0146] The term "biopolymer" refers to a material made from biogenic raw materials (renewable resources) and / or is biodegradable (biogenic and / or biodegradable polymer). This includes bio-based biopolymers, which may or may not be biodegradable, as well as petroleum-based polymers, which are biodegradable. This distinguishes them from conventional, petroleum-based materials or plastics, which are not biodegradable, such as polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC).

[0147] The term "rubber" refers to a high-molecular-weight, uncrosslinked polymeric material with rubber-like elastic properties at room temperature (25°C). At higher temperatures or under the influence of deformation forces, rubber exhibits increasingly viscous flow, thus allowing it to be reshaped under suitable conditions.

[0148] Rubber-elastic behavior is characterized by a relatively low shear modulus and a rather weak temperature dependence. It is caused by changes in entropy. Stretching forces the rubber-elastic material into a more ordered configuration, which leads to a decrease in entropy. After the force is removed, the polymers therefore return to their original position and the entropy increases again.

[0149] The term "polyurethane" (PU, DIN abbreviation: PUR) refers to a plastic or synthetic resin that is produced by the polyaddition reaction of diols or polyols with polyisocyanates. The urethane group is characteristic of a polyurethane.

[0150] Within the scope of the present invention, thermoplastic polymers are particularly preferred in this context. Particularly suitable polymers include the following: acrylonitrile-ethylene-propylene-(diene)-styrene copolymer, acrylonitrile-methacrylate copolymer, acrylonitrile-methyl methacrylate copolymer, acrylonitrile-chlorinated polyethylene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-ethylene-propylene-styrene copolymer, aromatic polyesters, acrylonitrile-styrene-acrylate copolymer, butadiene-styrene copolymer, cellulose acetate, cellulose acetobutyrate, cellulose acetopropionate, hydrogenated cellulose, carboxymethylcellulose, cellulose nitrate, cellulose propionate, cellulose triacetate, polyvinyl chloride, ethylene-acrylic acid copolymer, ethylene-butyl acrylate copolymer, ethylene-chlorotrifluoroethylene copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylate copolymer. Ethylene methacrylic acid copolymer, ethylene tetrafluoroethylene copolymer,Ethylen-Vinylalkohol-Copolymer, Ethylen-Buten- Copolymer, Ethylcellulose, Polystyrol, Polyfluorethylenpropylen, Methylmethacrylat-Acrylnitril-Butadien-Styrol-Copolymer, Methylmethacrylat- Butadien-Styrol-Copolymer, Methylcellulose, Polyamid 11 , Polyamid 12, Polyamid 46, Polyamid 6, Polyamid 6-3-T, Polyamid 6-Terephthalsäure-Copolymer, Polyamid 66, Polyamid 69, Polyamid 610, Polyamid 612, Polyamid 6I, Polyamid MXD 6, Polyamid PDA-T, Polyamid, Polyarylether, Polyaryletherketon, Polyamidimid, Polyarylamid, Polyaminobismaleinimid, Polyarylate, Polybuten-1 , Polybutylacrylat, Polybenzimidazol, Polybismaleinimid, Polyoxadiazobenzimidazol, Polybutylenterephthalat, Polycarbonat, Polychlortrifluorethylen, Polyethylen, Polyestercarbonat, Polyaryletherketon, Polyetheretherketon, Polyetherimid, Polyetherketon, Polyethylenoxid, Polyarylethersulfon, Polyethylenterephthalat, Polyimid, Polyisobutylen, Polyisocyanurat, Polyimidsulfon, Polymethacrylimid, Polymethacrylat, Poly-4-methylpenten-1,Polyacetal, Polypropylen, Polyphenylenoxid, Polypropylenoxid, Polyphenylensulfid, Polyphenylensulfon, Polystyrol, Polysulfon, Polytetrafluroethylen, Polyurethan, Polyvinylacetat, Polyvinylalkohol, Polyvinylbutyral, Polyvinylchlorid, Polyvinylidenchlorid, Polyvinylidenfluorid, Polyvinylfluorid, Polyvinylmethylether, Polyvinylpyrrolidon, Styrol-Butadien-Copolymer, Styrol-Isopren-Copolymer, Styrol- Maleinsäureanhydrid-Copolymer, Styrol-Maleinsäureanhydrid-Butadien- Copolymer, Styrol-Methylmethacrylat-Copolymer, Styrol-Methylstyrol-Copolymer, Styrol-Acrylnitril-Copolymer, Vinylchlorid-Ethylen-Copolymer, Vinylchlorid- Methacrylat-Copolymer, Vinylchlorid-Maleinsäureanhydrid-Copolymer, Vinylchlorid-Maleinimid-Copolymer, Vinylchlorid-Methylmethacrylat-Copolymer, Vinylchlorid-Octylacrylat-Copolymer, Vinylchlorid-Vinylacetat-Copolymer, Vinylchlorid-Vinylidenchlorid-Copolymer und Vinylchlorid-Vinylidenchlorid- Acrylnitril-Copolymer.,

[0151] Furthermore, the use of the following rubbers is also particularly advantageous: naturally occurring polyisoprene, especially cis-1,4-polyisoprene (natural rubber; NR) and trans-1,4-polyisoprene (gutta-percha), especially natural rubber; Nitrile rubber (copolymer of butadiene and acrylonitrile; poly(acrylonitrile-co-1,3-butadiene; NBR; so-called Buna N rubber); butadiene rubber (polybutadiene; BR); acrylic rubber (polyacrylic rubber; ACM, ABR); fluororubber (FPM); styrene-butadiene rubber (copolymer of styrene and butadiene; SBR); styrene-isoprene-butadiene rubber (copolymer of styrene, isoprene, and butadiene; SIBR); polybutadiene; synthetic isoprene rubber (polyisoprene; IR); ethylene-propylene rubber (copolymer of ethylene and propylene; EPM); ethylene-propylene diene rubber (terpolymer of ethylene, propylene, and a diene component; EPDM); butyl rubber (copolymer of isobutylene and Isoprene; IIR); Ethylene-vinyl acetate rubber (Copolymer of ethylene and vinyl acetate; EVM);Ethylene-methyl acrylate rubber (copolymer of ethylene and methyl acrylate; AEM); epoxy rubber, such as polychloromethyloxirane (epichlorohydrin polymer; CO), ethylene oxide (oxirane) - chloromethyloxirane (epichlorohydrin polymer; ECO), epichlorohydrin - ethylene oxide - allyl glycidyl ether copolymer (GECO), epichlorohydrin - allyl glycidyl ether copolymer (GCO) and propylene oxide - allyl glycidyl ether copolymer (GPO); polynorbornene rubber (polymer of bicyclo[2.2.1]hept-2-ene (2-norbornene); PNR); polyalkenylene (polymer of cycloolefins); Silicone rubber (Q), like silicone rubber but with methyl substituents on the polymer chain (MQ; e.g., dimethylpolysiloxane), silicone rubber with methyl vinyl and vinyl substituent groups on the polymer chain (VMQ), silicone rubber with phenyl and methyl substituents on the polymer chain (PMQ), silicone rubber with fluorine and methyl groups on the polymer chain (FMQ), silicone rubber with fluorine, methyl, and vinyl substituents on the polymer chain (FVMQ); polyurethane rubber;Thiol rubber; halogenated butyl rubber, such as bromobutyl rubber (BIIR) and chlorobutyl rubber (CIIR); chloropolyethylene (CM); chlorosulfonylpolyethylene (CSM); hydrogenated nitrile rubber (HNBR); and polyphosphazene.

[0152] Particularly preferred nitrile rubbers include statistical terpolymers of acrylonitrile, butadiene, and a carboxylic acid, such as methacrylic acid. In this context, the nitrile rubber preferably comprises, based on the total weight of the polymer, the following principal components: 15.0 wt.% to 42.0 wt.% acrylonitrile polymer; 1.0 wt.% to 10.0 wt.% carboxylic acid; and the remainder being predominantly butadiene (e.g., 38.0 wt.% to 75.0 wt.%). Typically, the composition is: 20.0 wt.% to 40.0 wt.% acrylonitrile polymer; 3.0 wt.% to 8.0 wt.% carboxylic acid; and 40.0 wt.% to 65.0 wt.% or 67.0 wt.% butadiene. Particularly preferred nitrile rubbers include a terpolymer of acrylonitrile, butadiene and a carboxylic acid, wherein the acrylonitrile content is less than 35.0 wt.% and the carboxylic acid content is less than 10.0 wt.%, the butadiene content being the remaining remainder.Even more preferred nitrile rubbers may include the following amounts: 20.0 wt.% to 30.0 wt.% acrylonitrile polymer, 4.0 wt.% to 6.0 wt.% carboxylic acid and the remainder is predominantly butadiene.

[0153] The use of nitrogen-containing polymers, in particular polyamides, is especially advantageous within the scope of the present invention. Polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 6-3-T, polyamide 6-terephthalic acid copolymer, polyamide 66, polyamide 69, polyamide 610, polyamide 612, polyamide 6I, polyamide MXD 6 and / or polyamide PDA-T, especially polyamide 12, are particularly preferred.

[0154] Furthermore, the use of biodegradable or resorbable polymers, especially resorbable polyesters, is particularly advantageous. The term "resorption" (from the Latin resorbere = "to absorb") refers to the uptake of substances in biological systems, particularly in the human organism. Of particular interest here are materials that can be used for the production of resorbable implants.

[0155] According to the invention, particularly preferred resorbable polymers comprise repeating units of lactic acid, hydroxybutyric acid, and / or glycolic acid, preferably lactic acid and / or glycolic acid, and especially lactic acid. Polylactic acids are particularly preferred. Furthermore, the use of poly(dioxanone) is also particularly advantageous.

[0156] Here, "polylactic acid" refers to polymers composed of lactic acid units. Such polylactic acids are typically produced by the condensation of lactic acids, but can also be obtained through the ring-opening polymerization of lactides under suitable conditions.

[0157] Particularly suitable resorbable polymers according to the invention include poly(glycolide-co-L-lactide), poly(L-lactide), poly(L-lactide-co-caprolactone), poly(L-lactide-co-glycolide), poly(L-lactide-co-D,L-lactide), poly(D,L-lactide-co-glycolide) and poly(dioxanone). Such polymers are commercially available, for example, from Boehringer Ingelheim Pharma KG (Germany) under the trade names Resomer® GL 903, Resomer® L 206 S, Resomer® L 207 S, Resomer® L 209 S, Resomer® L 210, Resomer® L 210 S, Resomer® LC 703 S, Resomer® LG 824 S, Resomer® LG 855 S, Resomer® LG 857 S, Resomer® LR 704 S, Resomer® LR 706 S, Resomer® LR 708, Resomer® LR 927 S, Resomer® RG 509 S and Resomer® X 206 S.

[0158] Particularly advantageous biodegradable or resorbable polymers for the purposes of the present invention, preferably resorbable polyesters, preferably lactic acid polymers, in particular poly-D-, poly-L- or poly-D,L-lactic acids, have a number-average molecular weight (Mn), preferably determined by gel permeation chromatography against narrowly divided polystyrene standards or by end-group titration, greater than 500 g / mol, preferably greater than 1,000 g / mol, particularly preferably greater than 5,000 g / mol, expediently greater than 10,000 g / mol, and in particular greater than 25,000 g / mol. On the other hand, the number-average molecular weight of preferred resorbable polymers is less than 1,000,000 g / mol, expediently less than 500,000 g / mol, advantageously less than 100,000 g / mol, and in particular at most 50,000 g / mol. A numerical average of the molecular weight in the range of 500 g / mol to 50,000 g / mol has proven particularly useful within the scope of the present invention.

[0159] The weight mean molecular weight (Mw) of preferred resorbable polymers, preferably resorbable polyesters, advantageously lactic acid polymers, in particular poly-D-, poly-L- or poly-D,L-lactic acids, preferably determined by gel permeation chromatography against narrowly divided polystyrene standards, is preferably in the range of 750 g / mol to 5,000,000 g / mol, more preferably in the range of 750 g / mol to 1,000,000 g / mol, particularly preferably in the range of 750 g / mol to 500,000 g / mol, and particularly in the range of 750 g / mol to 250,000 g / mol, and the polydispersity of these polymers is advantageously in the range of 1.5 to 5.

[0160] The inherent viscosity of particularly suitable biodegradable or resorbable polymers, preferably resorbable polyesters, preferably lactic acid polymers, in particular poly-D-, poly-L- or poly-D, L-lactic acids, measured in chloroform at 25°C, 0.1% polymer concentration, is in the range of 0.5 dl / g to 8.0 dl / g, preferably in the range of 0.8 dl / g to 7.0 dl / g, and particularly in the range of 1.5 dl / g to 3.2 dl / g.

[0161] Furthermore, the inherent viscosity of particularly suitable, resorbable polymers, preferably resorbable polyesters, preferably lactic acid polymers, in particular poly-D-, poly-L- or poly-D, L-lactic acids, measured in hexafluoro-2-propanol at 30°C, 0.1% polymer concentration, is in the range of 1.0 dl / g to 2.6 dl / g, particularly in the range of 1.3 dl / g to 2.3 dl / g.

[0162] Furthermore, polymers are particularly suitable which have a melting temperature greater than 50°C, preferably of at least 60°C, preferably of greater than 150°C, particularly preferably in the range of 160°C to 210°C, especially in the range of 175°C to 195°C.

[0163] Particularly preferred thermoplastic polymers are polyamides and resorbable polymers, especially resorbable polyesters, and in particular lactic acid polymers. Furthermore, particularly preferred matrix polymers include polyvinyl chloride (PVC), polyurethane (PU), silicone, polypropylene (PP), polyethylene (PE), and polylactic acid (PLA). Thermoplastic polymers with a melting point (Tm) of less than 200°C are also preferred within the scope of the present invention.

[0164] Particularly preferred compositions contain 40.0 wt.% to 99.9 wt.% of at least one matrix polymer and 0.1 wt.% to 50.0 wt.% of at least one composite according to the invention.

[0165] The composition can be prepared in a manner known per se by mixing the components.

[0166] The composition can then be further processed in the usual way, in particular granulated, crushed, ground, extruded, injection molded or foamed.

[0167] In a particularly preferred embodiment of the present invention, the composites according to the invention are first crushed or ground, preferably to an average fiber length of less than 5 mm, in particular to an average fiber length of less than 3.5 mm, particularly preferably less than 500 pm, and then mixed with at least one thermoplastic polymer.

[0168] Furthermore, the composites according to the invention can be processed and / or used directly, i.e. without the addition of additional polymers.

[0169] The advantages of the composites according to the invention are particularly evident during granulation, milling, tableting, extrusion, injection molding, melt pressing, and / or foaming of the composites. Within the scope of the present invention, the production of polymer foams is preferably carried out by generating or introducing a gaseous phase into a composition comprising the composite according to the invention and optionally at least one matrix polymer. The aim is to distribute the gas as uniformly as possible within the composition in order to achieve a uniform and homogeneous foam structure. The gas can be introduced in various ways.

[0170] Preferably, the gas phase is generated by adding a blowing agent. Blowing agents are substances that release gases through chemical reactions (chemical blowing agents) or phase transitions (physical blowing agents). In foam extrusion or foam injection molding, the chemical blowing agent is added to the composition in the form of a masterbatch, or the physical blowing agent is injected directly into the melt under pressure. This injection is called direct gas injection and is used particularly in the processing of thermoplastic polymers.

[0171] Particularly for this application, it is advantageous if the composite according to the invention has a structure that allows a fluid substance, preferably the blowing agent, to penetrate the composite and preferably to at least partially dissolve it. Therefore, the composite is preferably at least partially permeable. This is preferably achieved by ensuring that at least 0.1%, preferably at least 0.5%, and more particularly 1.0% to 5% of the at least one fiber are not coated with calcium carbonate. This effect is preferably enhanced by gaps between individual calcium carbonate particles, which are preferably present and lead to the formation of corresponding microchannels for the fluid substance, especially for the blowing agent.

[0172] In a particularly preferred embodiment of the present invention, the composite is foamed in accordance with the procedure described in the publication by M. Avella, S. Cosco, ML Di Lorenzo, E. Di Pace, ME Errico, "Influence of CaCCh Nanoparticles Shape on Thermal and Crystallization Behavior of Isotactic Polypropylene based Nanocomposites," Journal of Thermal Analysis and Calorimetry, Vol. 80 (2005), pp. 131-136. The composite according to the invention is preferably gassed with CO2, preferably under high pressure, and expediently at room temperature. The CO2 is absorbed by the polymer, and its glass transition temperature is preferably lowered. Upon pressure reduction, the composite foams and preferably flows precisely out of the mold, preferably a Teflon mold. This method thus enables, in particular, the incorporation of thermolabile substances, especially antibiotics and osteoinductive proteins.

[0173] In a further particularly preferred embodiment, the composite according to the invention is used in barrier papers, especially for food and packaging.

[0174] The present invention will be further illustrated below by several examples and comparative examples, without this being intended to limit the inventive concept.

[0175] A) Composite particles

[0176] materials

[0177] Cellulose A (short fiber): Eucalyptus (UPM Euca), unmilled (mixture of eucalyptus dunnii and eucalyptus grandis) (ZS 1-3, 6+7, 8; R 1-3, 6+7, 8; Composites 1 - 3 as well as 6 and 7, 8 and 9)

[0178] Pulp B (short fiber, eucalyptus): (ZS 4, R 4, composite 4) Filler: PCC suspension for reference papers R 1-3, 6+7, 8 and R 4 from comparison example 1

[0179] Comparative example 1 PCC (PCC suspension for reference papers R 1-3, 6+7, 8 and R 4)

[0180] Reaction vessel: Fumigation vessel with 8 dm³ 3 Filling volume, equipped with an anchor stirring device and a pH electrode.

[0181] 4 dm 3 Calcium hydroxide suspension with a CaO concentration of 73 g CaO / dm³ 3 The system was brought to an initial temperature of 10.2 °C. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 was introduced, with a gas flow rate of 6.8 dm³ / h. 3 The precipitation of calcium carbonate is approximately 100 nm per hour per gram of CaO. This precipitation is complete once a pH of 7.0 is reached. The precipitation lasted 55 minutes. The final sample contains no basic calcium carbonate. The calcium carbonate particles have a mean primary particle size, determined by electron microscopy, of approximately 100 nm.

[0182] Example 1 - Composite 1

[0183] Reaction vessel: Fumigation vessel with 400 dm³ 3 Filling volume, equipped with an Intermig stirring element and a pH electrode. 275 dm³3 A 3% cellulose fiber suspension (cellulose A) was treated with a 5.9% calcium hydroxide suspension (92 g CaO / dm³) at an initial temperature of 28°C. 3 ) (based on the amount of fiber suspension; 16.2 dm³) 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 16.8 dm³. 3 The precipitation of calcium carbonate cellulose composite is complete when the pH drops to 7.0. The precipitation lasted 41 minutes. The final sample contains no basic calcium carbonate.

[0184] Example 2 - Composite 2

[0185] Reaction vessel: Fumigation vessel with 400 dm³ 3 Filling volume, equipped with an Intermig stirring device and a pH electrode.

[0186] 275 dm 3A 3% cellulose fiber suspension (cellulose A) was brought to an initial temperature of 28°C. 5.9% calcium hydroxide suspension (92 g CaO / dm³) 3 ) (based on the amount of fiber suspension; 16.2 dm³) 3 ) are provided, of which 1.2% of the calcium hydroxide suspension (based on the amount of fiber suspension; 3.2 dm³) will be used. 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 16.8 dm³. 3 The amount of CaO is / h / g. The suspension is aerated until the pH reaches 7.0. Then the remaining 4.7% (13.0 dm³) is removed. 3Calcium hydroxide suspension was continuously added to maintain / control the pH within a range of approximately 7–10 during fumigation. The precipitation of the calcium carbonate cellulose composite, after the addition of the remaining calcium hydroxide suspension, was complete when the pH dropped to 7.0. The precipitation lasted 41 minutes. The final sample contained no basic calcium carbonate.

[0187] Example 3 - Composite 3

[0188] Reaction vessel: Fumigation vessel with 400 dm³ 3 Filling volume, equipped with an Intermig stirring device and a pH electrode.

[0189] 275 dm 3 A 3% cellulose fiber suspension (cellulose A) was brought to an initial temperature of 28°C. 5.9% calcium hydroxide suspension (92 g CaO / dm³) 3 ) (based on the amount of fiber suspension; 16.2 dm³) 3) are provided, of which 0.3% of the calcium hydroxide suspension (based on the amount of fiber suspension; 0.8 dm³) will be used. 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 11.4 dm³. 3 The amount of CaO is / h / g. The suspension is aerated until the pH reaches 7.0. Then the remaining 5.6% (15.4 dm³) is removed. 3 Calcium hydroxide suspension was continuously added so that the pH was maintained / controlled within a range of approximately 7–10 during fumigation. The precipitation of the calcium carbonate cellulose composite, after the addition of the remaining calcium hydroxide suspension, was complete when the pH dropped to 7.0. The precipitation lasted 48 minutes. The final sample contained no basic calcium carbonate.

[0190] Example 4 - Composite 4

[0191] Reaction vessel: Fumigation vessel with 20,000 dm³ 3Filling volume, equipped with a gassing star and a pH electrode.

[0192] 17,000 dm 3 A 3% cellulose fiber suspension (cellulose B) was brought to an initial temperature of 17.2°C. 4.7% calcium hydroxide suspension (102 g CaO / dm³) 3 ) (based on the amount of fiber suspension; 807 dm³ 3 ) are provided, of which 0.47% of the calcium hydroxide suspension (based on the amount of fiber suspension; 81 dm³) will be used. 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CO2-air mixture with 10% CO2 and 90% N2 is introduced, with a gas flow rate of 23.7 dm³. 3 The amount of calcium hydroxide suspension is / h / g CaO. The suspension is gassed until the pH reaches 8.0. Then, the remaining 4.23% of the calcium hydroxide suspension (based on the amount of fiber suspension; 726 dm³) is removed. 3Calcium hydroxide suspension is continuously added to maintain / control the pH within a range of approximately 7–10 during gassing. The precipitation of the calcium carbonate pulp composite, after the addition of the remaining calcium hydroxide suspension, is complete when the pH drops to 7.0. The precipitation lasted 47 minutes. The final sample contains no basic calcium carbonate.

[0193] Example 6 - Composite 6

[0194] Reaction vessel: Fumigation vessel with 400 dm³ 3 Filling volume, equipped with an Intermig stirring device and a pH electrode.

[0195] 220 dm 3 A 3% cellulose fiber suspension (cellulose A) was brought to an initial temperature of 45°C. A 12.3% calcium hydroxide suspension (92 g CaO / dm³) was then added. 3 ) (based on the amount of fiber suspension; 27 dm³) 3 ) are provided, of which 6.15% (13.5 dm) will be used. 3The calcium hydroxide suspension (based on the amount of fiber suspension) was directly mixed in and homogenized with stirring for 5 minutes. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 was introduced, with a gas flow rate of 5.2 dm³ / h. 3 The amount of CaO is / h / g. The suspension is aerated until the pH value of 7.0 is reached. Then the remaining 6.15% (13.5 dm³) is removed. 3 Calcium hydroxide suspension was continuously added to maintain / control the pH within a range of approximately 7–10 during gassing. The precipitation of the calcium carbonate pulp composite, after the addition of the remaining calcium hydroxide suspension, was complete when the pH dropped to 7.0. The precipitation lasted 60 minutes. The final sample contained no basic calcium carbonate.

[0196] Example 7 - Composite 7

[0197] Reaction vessel: Fumigation vessel with 10 dm³ 3Filling volume, equipped with a propeller stirrer and a pH electrode.

[0198] 6 dm 3 A 3% cellulose suspension (cellulose A) was heated to an initial temperature of 70°C. 15.0% (based on the amount of fiber suspension) of a mixture consisting of 0.900 dm³ 3 Calcium hydroxide suspension (92 g CaO / dm 3 6.7% aragonite seed crystals, atro-calcium hydroxide (SCHAEFER PRECARB® 600 from Schaefer Kalk GmbH & Co. KG (Germany)), and 2.0% H3PO4 (commercial product / 85% atro-calcium hydroxide) are added to the pulp suspension and homogenized with stirring for 5 minutes. A CC-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 6.0 dm³ / h. 3 The precipitation of calcium carbonate cellulose composite is complete when the pH drops to 7.0. The precipitation lasted 26 minutes. The final sample contains no basic calcium carbonate.

[0199] Example 8 - Composite 8

[0200] Reaction vessel: Fumigation vessel with 10 dm³ 3 Filling volume, equipped with a propeller stirrer and a pH electrode.

[0201] 6 dm 3 A 3% cellulose fiber suspension (cellulose A) was treated with a 5.9% calcium hydroxide suspension (92 g CaO / dm³) at an initial temperature of 30°C. 3 ) (based on the amount of fiber suspension; 0.35 dm³) 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CO2-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 6.0 dm³. 3 The precipitation of calcium carbonate cellulose composite is complete when the pH drops to 7.0. The precipitation lasted 30 minutes. The final sample contains no basic calcium carbonate.

[0202] Example 9 - Composite 9

[0203] Reaction vessel: Fumigation vessel with 400 dm³ 3Filling volume, equipped with an Intermig stirring element and a pH electrode. 275 dm³ 3 A 3% cellulose fiber suspension (cellulose A) was treated with 23.6% calcium hydroxide suspension (92 g CaO / dm³) at an initial temperature of 30°C. 3 ) (based on the amount of fiber suspension; 64.8 dm³) 3 ) directly mixed in and homogenized for 5 minutes while stirring. A CCh-air mixture with approximately 20% CO2 and approximately 80% N2 is introduced, with a gas flow rate of 16.8 dm³. 3 The precipitation of calcium carbonate cellulose composite is complete when the pH drops to 7.0. The precipitation lasted 151 minutes. The final sample contains no basic calcium carbonate.

[0204] Laboratory papers

[0205] The sample materials were standardized to a uniform bulk filler content of 20%. Composites with a higher filler content were mixed with the respective cellulose. This mixture was diluted to 10 liters in a distribution device using 40 g of total solids. The retention of the individual composites and their influence on the paper properties were then assessed. Laboratory papers were produced under comparable conditions.

[0206] Laboratory sheet formation (according to Rapid Köthen)

[0207] Leaf formation with 80 g / m² 2

[0208] 1. Fill the leaf formation column to up to 4 liters while simultaneously adding the fiber suspension.

[0209] 2. Swirling of the suspension for fiber distribution

[0210] 3. Short calming period

[0211] 4. Subsequently, dehydrate the suspension by siphoning off excess water.

[0212] 5. After the water is extracted, the damp fiber remains on the sieve.

[0213] 6. Courging using a courging roller and courging board, then tapping off the sieve.

[0214] 7. Vacuum drying at 95 °C between couch board and cover sheet

[0215] To assess the effect of the composites, two references were established: o 100% cellulose (designation: ZS 1-3, 6+7, 8 and ZS 4) o 20% PCC suspension (from comparison example 1) to cellulose in the thick range (designation: R 1-3, 6+7, 8 and R4)

[0216] Methodology - Paper tests

[0217] The following paper properties were tested on the laboratory sheets: o Basis weight according to DIN EN ISO 536:2020-05 o Thickness, density and specific volume according to DIN EN ISO 534:2012-02 o Tensile strength and elongation at break according to DIN EN ISO 1924-2:2009-05 o Tear resistance (Elmendorf method) according to DIN EN ISO 1974:2012-09 o Strip crush resistance (SCT) according to DIN 54518:2022-01 o Two-point flexural stiffness according to DIN 53121:2014-08 o Gurley air permeability according to ISO 5636-5:2013-11 o D-65 brightness according to ISO 2470-2:2008-11 o Opacity according to ISO 2471:2008-12

[0218] Implementation and results

[0219] Sample preparation

[0220] The sample material to be tested was conditioned according to DIN EN ISO 187:2023-02 at 23 ± 1°C and 50 ± 2 % relative humidity for at least 24 hours and tested under this climate.

[0221] Area-related mass

[0222] The area-related mass was determined according to DIN EN ISO 536:2020-05 using an analytical balance from Sartorius with an accuracy of 1 / 1000 g. Deviating from the standard, the area-related mass was determined on laboratory sheets with a test area of ​​317 cm². 2 Determined. An average value in g / m² was calculated from 15-18 individual measurements. 2 calculated.

[0223] Thickness, density, specific volume

[0224] The thickness was determined according to DIN EN ISO 534:2012-02 using a micrometer from Lorentzen & Wettre. An average value was calculated from 20 individual measurements.

[0225] The density and specific volume were calculated from the respective mean values ​​of mass per unit area and thickness.

[0226] Production of filter cake (composite)

[0227] 300 mL of homogenized sample are filtered under vacuum through a Büchner funnel (d=97 mm, hole diameter 1.5 mm). The resulting filter cake is dried at 130°C in a drying oven until a constant mass is achieved.

[0228] Ash content (in %)

[0229] Method of rapid incineration by Harry Gestigkeit:

[0230] The dried filter cake (approx. 5 g) is ashed in a porcelain crucible (V=50 mL) for 45 minutes with the switch set to "45% Watt" and "Continuous ON / ON*". The crucible is then placed in a muffle furnace at 450°C for 45 minutes. Bunsen burner method (burner, tripod, triangle for crucible):

[0231] The dried filter cake (approx. 5 g) is ashed in a porcelain pot over a Bunsen burner. The pot is then placed in a muffle furnace at 450°C for 45 minutes.

[0232] Microwave oven method, company CEM:

[0233] The dried filter cake (approx. 3 g) is ashed in a Teflon pot (V = 50 mL) for 30 minutes at 385° C.

[0234] Specific surface area BET

[0235] The specific surface area of ​​CaCO₃ (PCC, ash from the rapid ashing method) was determined using the GEMINI VII 2390a surface analyzer (with the FLOW PREP preparation station) from Micromeritics. Approximately 0.3 g of sample (ash) was dried overnight at 130°C under nitrogen and measured after cooling.

[0236] The specific surface area and pore volume of the composites were determined using the QuadraSorb Sl surface analyzer (with the FlowDegasser preparation station) from Quantachrome Instruments.

[0237] Approximately 0.3 g of sample was dried at 130°C for 2 hours under N2 and measured after cooling.

[0238] XRD (phase analysis / CaO content)

[0239] The crystal modification of CaCO₃ (PCC, basic calcium carbonate, composite and ash from the rapid ashing method) was determined using an X-ray diffractometer (D8 Endeavor). The sample was prepared and measured in a micro-sample holder. The measurement was evaluated quantitatively. The Rietveld method was used for quantitative phase analysis.

[0240] CILAS

[0241] The particle size distribution of the CaCO₃ (ash from the rapid ashing process) was determined using laser diffraction (CILAS 1064, Quantachrome). Dispersing solution: Hard water (20° dH, 0.1% NPP)

[0242] Sedigraph: The particle size distribution of CaCOa (ash from the rapid ashing method) was determined using the Sedigraph 5125 with MasterTech 51 from Micromeritics. Dispersing solution: 0.1% NPP solution.

[0243] REM

[0244] SEM images of various samples (PCC, cellulose, composite) and the ash (from the rapid ashing method) were taken with the scanning electron microscope DSM 962 (Zeiss).

[0245] For the measurement of the recorded particles, at least 15 particles were measured using the image processing software Digital Image Processing System at a magnification of preferably 10,000 times.

[0246] The sample was prepared on carbon pads. The sample was made conductive with a gold / palladium coating.

[0247] Breaking force / Elongation at break

[0248] The tensile strength and elongation were determined according to DIN EN ISO 1924-2:2009-05 using the Lorentzen & Wettre SE 062 / 064 tensile strength testing machine. The characteristic values ​​indicate the maximum width-related tensile force in kN / m and the maximum elongation in % at which the material fails and the specimen fractures. The energy absorption capacity (TEA) in J / m² was also determined. 2 certainly.

[0249] 15 mm wide material strips were tested at a constant elongation rate of 20 mm / min and a clamping length of 100 mm. Ten test specimens were measured, and an average value was calculated from the individual measurements.

[0250] Tear strength Elmendorf

[0251] The Elmendorf tear resistance was determined according to DIN EN ISO 1974:2012-09 using the ABB L&W Tearing Tester 298. The Elmendorf tear resistance indicates the force applied suddenly by means of a pendulum that is necessary to continue tearing a cut specimen out of the plane of the sheet.

[0252] Four test sheets (62 mm high, 50 mm wide) of the same side were combined to form a test set, and 10 test sets were tested. An average value was calculated from 10 individual values ​​and expressed in mN.

[0253] Pendulum A (0 - 2000 mN) was used for all tests. Strip compression resistance (SCT)

[0254] The strip compression strength (short-span compression test, SCT) was determined according to DIN 54518:2022-01 using the Compression Strength Tester STFI 93381 3-1 from Lorentzen & Wettre. The SCT is defined as the maximum compressive breaking force in kN / m, based on a sample width of 15 mm, which the sample resists a specified compression in the plane of the leaf.

[0255] Twenty strips of material were tested and an average value was calculated from the individual measurements.

[0256] Gurley air permeability

[0257] The determination of air permeability and air resistance according to Gurley was carried out according to ISO 5636-5:2013-11 using the Gurley densometer 4110, type 21-C from Messmer.

[0258] The test was performed using a measuring range of 100 cm. 3 .

[0259] Five measurements were taken with airflow from top to bottom and five measurements with the airflow reversed. An average was calculated from 10 individual measurements.

[0260] D65 Brightness

[0261] The test was performed using the ABB L&W Elrepho 950 spectrophotometer according to ISO 2470-2:2008-11. D65 brightness refers to the reflectance value (in %) measured in a reflectometer using D65 light and a filter with a transmission maximum at a wavelength of 457 nm. The measurements were carried out using the XLAV aperture (34 mm).

[0262] An average value was calculated from 5 individual measurements each of the top and bottom of the material.

[0263] opacity

[0264] The test was performed according to ISO 2471:2008-12 using the L&W Elrepho 950 spectrophotometer from ABB. Opacity indicates the light transmission of paper in the visible spectrum and is expressed as a percentage.

[0265] Measurements were taken using C / 2 illuminant and an XLAV aperture (34 mm). Five individual measurements each were taken of the top and bottom surfaces of the material. The results for the top and bottom surfaces are presented separately as mean values ​​if the difference between the two values ​​is greater than 0.2%. Otherwise, an overall mean value is given.

[0266] The results obtained are summarized in Tables 1 to 4.

[0267] The following abbreviations may be used:

[0268] MW average

[0269] SD Standard deviation n Number of individual measurements

[0270] OS top

[0271] US subpage

[0272] Table 1

[0273]

[0274] The composites exhibit comparable or better retention than the PCC slurry in the reference samples (see Table 1: filler retention and filler content in leaf).

[0275] Table 2

[0276]

[0277] The specific volume is not significantly affected by the use of the composites (see Table 2).

[0278] Table 3

[0279]

[0280]

[0281] Table 4

[0282]

[0283] The apparent leaf density is not significantly affected by the use of the composites (see Table 3).

[0284] The tensile strength decreases with the addition of filler. The composites exhibit positive behavior compared to PCC suspension, as improved fracture strength indices are observed at comparable or higher filler contents (see Table 3).

[0285] The elongation decreases with the addition of filler. The composites exhibit positive behavior compared to PCC suspension, as improved elongation is observed at comparable or higher filler contents (see Table 3).

[0286] The same effects can be observed for the TEA index (work absorption capacity) as for tensile strength and elongation (see Table 3).

[0287] The dynamic tear strength is also positively influenced by the addition of composites. With higher or comparable filler contents in the paper compared to metered PCC suspension, the tear strength index is sometimes significantly increased (see Table 3).

[0288] The 2-point bending stiffness is also positively influenced by the addition of composites. With higher or comparable filler contents in the paper compared to metered PCC suspension, the bending stiffness is increased (see Table 3).

[0289] The development of strip crush resistance also reflects previous strength developments. • At higher or comparable filler contents in the paper compared to metered PCC suspension, the strip crush resistance is increased (see Table 3).

[0290] The air permeability P decreases with the addition of the PCC suspension. The addition of the composites reduces the air permeability less significantly (Composite 1, Composite 2, Composite 6) or leaves it at the level of pure cellulose paper (Composite 3, Composite 7; see Table 4).

[0291] Gurley's air permeability is a measure of air resistance. The addition of composites 3 and 7 allows the initial air permeability level of pure cellulose papers to be achieved (see Table 4). The whiteness is not significantly affected by the addition of the composites (see Table 4).

[0292] The opacity is improved in particular by the addition of the composites Composite 3, Composite 6, Composite 7 (see Table 4).

[0293] In summary, positive effects on strength were observed based on laboratory-tested paper formation. With comparable filler contents in the paper, both static and dynamic strengths were increased. Furthermore, by carefully selecting the composite material, significant improvements are possible.

[0294] Increased strength can be achieved compared to paper filled with pure PCC. Furthermore, an increase in opacity of 3-4 percentage points can be observed, particularly when using Composite 3, Composite 6, and Composite 7.

[0295] Incineration of the materials

[0296] The resulting composites were ashed at 450°C in a muffle furnace and the resulting materials were characterized as follows: qualitative phase analysis (XRD), determination of particle size distribution using sedigraphy, pH control, and scanning electron microscopy.

[0297] The results obtained are summarized in Table 5. The SEM images of the PCC suspension (Comparison Example 1 PCC), composite 1, composite 2, composite 3, composite 4, composite 6, composite 7, composite 8, and composite 9 are shown in Figs. 3a, 4a, 5a, 6a, 7a, 8a, 9a, and 10a (1,000x magnification) and in Figs. 2b, 3b, 4b, 5b, 6b, 7b, 8b, 9b, and 10b (5,000x magnification).

[0298] Table 5

[0299]

[0300] Table 5-2

[0301] The ash content was determined using the "rapid ashing" method. The analysis results marked with ** were determined from the ash obtained.

[0302] In particular, the advantageous properties of composite 7 shown in Tables 3 and 4 are surprising, since the calcium carbonate particles of this composite have a mean particle size of 1872 nm, whereas EP 3 127 868 B1 and EP 3 127 867 A1 emphasize the need to use significantly smaller calcium carbonate particles with a mean particle size <1 pm.

[0303] B) Plastic applications

[0304] Compounding using ZE25x47D + cold granulation (FW bath, Primo 60E cutting mill). a) Materials

[0305] PLA (Ingeo™ Biopolymer 3251 D).

[0306] Composite: Composite 6 (Pre-shredded with a cutting mill (Retsch cutting mill SM 300, 6-disc rotor, speed: 1500 rpm; Recipe: 1.1 ; Fiber feed into the twin-screw extruder (TS) via twin-screw side feeding (TSF)).

[0307] Reference CaCOs (Formula: 1.2 (PLA / CaCO3); SCHAEFER PRECARB® 100 from Schaefer Kalk GmbH & Co. KG (Germany), calcite / scalenohedral, average particle size (Segraph): dso% = 1.0 pm; specific surface area (BET): 9 m² 2 / g). b) Compounding using twin-screw extruder ZE25Ax47D

[0308] • Total throughput of the ZE: 5 kg / h

[0309] Table 6: PI_A / Fiber and PLA / CaCOs formulations (90 / 10 w / w)

[0310] The focus was exclusively on volumetric dosing using a twin-screw side-feeding device. Fiber feeding via ZSFE into the ZE occurred at approximately 20D.

[0311] Table 7: ZE and ZSFE settings according to the component ratio, dosage The design aimed for a PLA / fiber ratio of 90 / 10 w / w.

[0312] Table 8: Temperature profile of the ZE (cooled intake, 8 heating zones)

[0313] The housing and screw configuration of the ZE is shown in Fig. 1.

[0314] Use of conveying elements and dispersive mixing elements (kneading blocks) with high shear energy input.

[0315] Degassing: vacuum degassing (at approx. 0.6 bar),

[0316] Degassing insert type B.

[0317] Table 9: Compounding parameters c) Test specimen injection molding

[0318] Injection molding of 6 type 1A test specimens per setting

[0319] Table 10

[0320] Compounding with PLA using a composite material made of cellulose and calcium carbonate (composite 6 (calcite / scalenohedral)) results in a compound with improved mechanical properties compared to the reference PCC (calcite / scalenohedral). In particular, compounds with an improved modulus of elasticity (Table 10) are obtained, which can be of particular interest when improving the impact strength and notched impact strength of the compounds.

[0321] Furthermore, the composite material, which is crushed using a cutting mill, can surprisingly be dosed well during extrusion, resulting in a compound with homogeneously distributed composite fibers.

Claims

Patent claims:

1. Method for producing a composite of calcium carbonate particles adhering to the surface of at least one fiber, wherein the composite has a specific surface area of ​​less than 30 m² 2 / g and wherein a weight ratio between the calcium carbonate particles and the at least one fiber is 5:95 to 95:5, comprising the synthesis of calcium carbonate in a reaction vessel using a carbonation process, wherein (1) an aqueous suspension is presented which contains at least one fiber, (2) an aqueous solution of a calcium salt or an aqueous suspension of slaked lime is added and (3) a carbon dioxide-containing gas is introduced into the reaction vessel.

2. Method according to claim 1, characterized in that the aqueous suspension in step (1) contains calcium carbonate seed particles.

3. Method according to claim 1 or 2, characterized in that in step (1) an aqueous suspension is provided which contains at least one fiber and at least one calcium salt, in particular slaked lime.

4. Method according to claim 3, characterized in that in step (1) an aqueous suspension is provided which contains the at least one fiber and, in each case based on the total amount of calcium salt or slaked lime added in step (2), 1 / 25 to 3 / 4 wt.%, preferably 1 / 23 to 3 / 5 wt.%, in particular 1 / 20 to 1 / 2, of the calcium salt, in particular of the slaked lime.

5. Method according to at least one of the preceding claims, characterized in that in step (2) the aqueous solution of a calcium salt or the aqueous suspension of slaked lime is added at a pH in the range of 7-10.

6. A method according to at least one of the preceding claims, characterized in that in step (3) the carbon dioxide-containing gas comprises 1% to 40%, preferably 5% to 30%, in particular 10% to 20% CO2 and 60% to 99%, preferably 70% to 95%, in particular 80% to 90% N2 and other gases other than CO2 and / or the carbon dioxide-containing gas with a gas flow rate, based on the gas flow rate of CO2, in Range from 0.1 to 50.0 dm 3 CCh / h / g CaO, preferably in the range of 2.5 to 35.0 dm 3 CO2 / h / g CaO, especially in the range of 5.0 to 25.0 dm 3 CO2 / h / g CaO is introduced into the reaction vessel.

7. Method according to at least one of the preceding claims, characterized in that the fiber is a chemical fiber, a regenerated fiber, a natural fiber; or a fiber made from cellulose.

8. Method according to at least one of the preceding claims, characterized in that the introduction of the carbon dioxide-containing gas into the reaction vessel is carried out until the pH value of the aqueous suspension drops to 7.0 or less.

9. Composite of calcium carbonate particles and at least one fiber, wherein the calcium carbonate particles preferably have a mean primary particle size, determined by observation with an electron microscope, of greater than 200 nm, wherein the calcium carbonate particles adhere to the surface of the at least one fiber, the weight ratio between the calcium carbonate particles and the fiber is 5:95 to 95:5, and the composite has a specific surface area of ​​less than 30 m². 2 / g, preferably less than 9 m 2 / g, preferably in the range of 1 to 8 m 2 / g, especially in the range of 2 to 7 m 2 / g, and wherein the composite is obtainable by the method according to at least one of claims 1-8.

10. Composite according to claim 9, characterized in that the fiber is a chemical fiber, a regenerated fiber, a natural fiber; or a fiber made from cellulose.

11. Composite according to claim 9 or 10, characterized in that after ashing of the composite at 450°C, the following results are obtained from the remaining ash: (a) dso according to SEM: greater than 150 nm, preferably greater than 200 nm, particularly preferably greater than 500 nm, in particular 1 pm to 50 pm; and / or (b) BET: 1-10 g / m 2 preferably 1.25–6.0 g / m³ 2 ; particularly preferably 1.5–5.0 g / m³ 2 ; in particular 2.0–4.5 g / m³ 2 ; and / or (c) dso according to CILAS greater than 1.0 pm, preferably greater than 1.5 pm, particularly preferably greater than 2.0 pm, in particular 2.2 pm to 10.0 pm; and / or (d) dso according to Sedigraph 1.0 pm, preferably greater than 1.5 pm, particularly preferably greater than 1.7 pm, in particular 1.8 pm to 5.0 pm.

12. Product comprising the composite according to claim 9, 10 or 11, wherein the product does not include paper intended for use in cigarettes.

13. Product according to claim 12, comprising a sheet, a paper containing the composite as a filler, a coating containing the composite, or a resin mixture obtained by mixing the composite and a resin.

14. Product according to claim 12 or 13, comprising a paper having the following properties: o specific volume preferably greater than 1.70 g / cm³ 3 , especially preferred to be greater than 1.84 g / cm³ 3 , especially greater than 1.86 g / cm³ 3 , and / or; o apparent leaf density preferably less than 0.60 g / cm² 3 , especially those smaller than 0.58 g / cm³ 3 , especially less than 0.55 g / cm³ 3, and / or o breaking strength index MD preferably greater than 8.6 Nm / g, particularly preferably greater than 11.0 Nm / g, particularly greater than 15.0 Nm / g, and / or o elongation at break MD preferably greater than 0.53%, particularly preferably greater than 0.70%, particularly greater than 0.77%, and / or o TEA index MD preferably greater than 27 J / kg, particularly preferably greater than 50 J / kg, particularly greater than 70 J / kg, and / or o tensile strength index (Elmendorf) preferably greater than 1.30 mNm / g, particularly preferably greater than 1.60 mNm / g, particularly greater than 1.69 mNm / g, and / or o 2-point flexural stiffness preferably greater than 0.30 Nm, particularly preferably greater than 0.40 Nm, particularly greater than 0.44 Nm, and / or o strip puncture resistance (SCT index) preferably less than 20.4 Nm / g, particularly preferably less than 16.1 Nm / g, particularly less than 12.6 Nm / g, and / or air permeability P preferably greater than 40.0 pm / Pa*s, particularly preferably greater than 62.4 m / Pa*s, particularly greater than 80.0 pm / Pa*s,and / or o Air permeability Gurley preferably less than 4.00 s / 100 ml, particularly preferably less than 2.20 s / 100 ml, particularly less than 1.57 s / 100 ml, and / or o Whiteness D65 OS preferably greater than 88.9%, particularly preferably greater than 89.1%, particularly greater than 90.0%, and / or o Opacity C / 2 preferably greater than 84.2%, particularly preferably greater than 85.1%, particularly greater than 86.0%.

15. Product according to claim 12, 13 or 14 further comprising at least one polymer, in particular a biopolymer.

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