A micro-flocculent filler for papermaking, its preparation method and application

Abstract

This invention relates to a papermaking additive, specifically to a micro-flocculated filler for papermaking, its preparation method, and its application. This invention targets positively charged filler suspensions, employing negatively charged microflocculators to achieve microflocculation, resulting in mutual adsorption between anions and cations. Furthermore, it utilizes a combination of three specific microflocculators with different molecular weights, alternating and filling the surface to achieve a dense and sufficient coating. Moreover, the outer side of the microflocculated coating is negatively charged, overcoming the possibility of re-agglomeration between microflocculated functional groups, thereby allowing for controllable particle size of the microflocculated filler.

Description

Technical Field

[0001] This invention relates to a papermaking additive, specifically to a micro-flocculent filler for papermaking, its preparation method, and its application. Background Technology

[0002] In papermaking, fillers play multiple and crucial roles, while also presenting several challenges. On one hand, fillers reflect, scatter, and refract light. These unique optical properties significantly enhance the opacity and whiteness of paper, making it visually whiter and brighter, meeting various printing and writing requirements. Simultaneously, when fillers fill the gaps between fibers, they act like tiny "fillers," effectively filling voids in the fiber network, significantly improving the smoothness of the paper surface, reducing unevenness, and enhancing the overall texture of the paper.

[0003] However, adding fillers can also have some adverse effects on paper. During the dewatering process in the papermaking wire section, the fillers move rapidly downwards with the white water due to the combined effects of gravity and vacuum suction. This results in a significant accumulation of filler particles on the reverse side of the paper web (the side in contact with the forming wire) when viewed vertically from the paper's cross-section, while the filler particles on the front side (the side away from the forming wire) are relatively fewer, exhibiting an uneven distribution of fillers in the vertical direction. This uneven distribution can lead to decreased paper strength, damage to the bonding force between fibers, and negative impacts on the paper's appearance. In this situation, simply increasing the amount of filler added to increase the filler content on the front side of the paper web will exacerbate the difference between the two sides and further reduce the paper's strength. This is because excessive filler addition will further damage the fiber network structure, making the paper more brittle. To address these issues, existing technology discloses the use of dual flocculants to flocculate fillers with cationic charges, where the first flocculant is amphoteric or cationic. However, using an amphoteric first flocculant can lead to the adsorption of opposite charges after the first flocculant coats the filler, resulting in larger flocs and uncontrollable particle size. Using a cationic first flocculant presents the problem of electrostatic repulsion and difficulty in coating. Therefore, the applicant attempted to use an anionic flocculant as the first flocculant, but found that flocculation was uncontrollable. Furthermore, in paper pulp, in addition to anionic fibers, there are also a certain amount of cationic fibers or cationic additives; using a single cationic flocculant can easily lead to mutual repulsion between the flocculant and the cationic fibers and / or the cationic flocculant itself. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing micro-flocculated fillers for papermaking. By using a specific combination of anionic micro-flocculators and amphoteric modifiers, controllable flocculation and retention of cationic fibers and cationic additives can be achieved.

[0005] First, the present invention provides a method for preparing micro-flocculated filler for papermaking, which includes the following steps: S1: Prepare an anionic microflocculator, wherein the microflocculator comprises a first microflocculator with a molecular weight of 1-2 million, a second microflocculator with a molecular weight of 2-4 million, and a third microflocculator with a molecular weight of 4-6 million, wherein the mass ratio of the first microflocculator, the second microflocculator, and the third microflocculator is 9-16:25-33:55-65; S2: Preparation of amphoteric modifiers; S3: The micro-flocculator and modifier are added sequentially to the positive-positive filler particle suspension to obtain the micro-flocculated filler.

[0006] Preferably, in step S1, the density of the first micro-flocculator is 0.988-1.0188 g / cm³. 3 The density of the second micro-flocculator is 1.018-1.058 g / cm³. 3 The density of the third micro-flocculator is 1.05-1.0798 g / cm³. 3 .

[0007] Preferably, in step S1, the anionic monomers used in the first microflocculator, the second microflocculator, and the third microflocculator are selected from the following compounds and their aqueous solutions and solids: (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and their copolymers, polymers, and mixtures.

[0008] Preferably, in step S1, the micro-flocculator has an anionic charge of 12-15 mol%.

[0009] Preferably, in step S2, the mass ratio of cationic monomer to anionic monomer in the modifier is 29.2-9.2:0.3-20.3.

[0010] Preferably, in step S2, the cationic monomer is selected from the following compounds and their aqueous solutions, solids, and salts: dimethylaminoethyl methacrylate (DMAEM), dimethylaminoethyl acrylate (OMAEA), diethylaminoethyl acrylate (DEAEA), diethylaminoethyl methacrylate (DEAEM), diallyl dimethyl ammonium chloride (DADMAC), acryloyloxyethyltrimethylammonium chloride (DAC), methacryloyloxyethyltrimethylammonium chloride (DMC), or copolymers and terpolymers and mixtures thereof in quaternary ammonium form obtained with dimethyl sulfate, methyl chloride, benzyl chloride; the anionic monomer is selected from the following compounds and their aqueous solutions and solids: (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and their copolymers, polymers, and mixtures.

[0011] Preferably, in step S2, the modifier has 5-70 mol% cationic charge and 0.2-20 mol% anionic charge. More preferably, the modifier is an amphoteric cation.

[0012] Preferably, in step S3, the filler particles are selected from precipitated calcium carbonate, a mixture of precipitated calcium carbonate particles and ground calcium carbonate particles, and talc microparticles, and the mass concentration of the filler particles in the suspension is 10-30%.

[0013] Secondly, the present invention also provides a micro-flocculent filler for papermaking prepared according to the above preparation method, wherein the micro-flocculent filler has a median particle size of 30-80 micrometers; an average controlled particle size of 40-60 micrometers; and a particle size distribution of 80% of the particles being 20-90 micrometers, and its surface having amphoteric functional groups.

[0014] Finally, the micro-flocculent filler provided by the present invention can be used in papermaking, wherein the micro-flocculent filler and the oven-dry mixing ratio of the pulp is 10-40:60-90, and the pulp contains cationic fibers and / or cationic additives in addition to anionic fibers.

[0015] Compared with existing publicly available technologies, the advantages of this invention are: Firstly, for positively charged filler suspensions, this invention employs negative microflocculation to achieve microflocculation, enabling the mutual adsorption of anions and cations. This is achieved through a combination of three specific microflocculating agents with different molecular weights: low-molecular-weight microflocculators disperse and move rapidly in the suspension, quickly neutralizing the positive charge of the filler; medium-molecular-weight microflocculators cause the filler to form micro-flocs, creating tight and strong bridges between filler particles or micro-flocs, increasing the strength and density of the micro-flocs; high-molecular-weight microflocculators connect multiple filler particles through a bridging mechanism, forming stronger and more controllable flocs. Furthermore, the three different molecular weight microflocculators are interleaved, resulting in a dense and sufficient coating surface. Moreover, the outer side of the microflocculation coating is negative, overcoming the possibility of re-agglomeration between microflocculation functional groups, thus allowing for controllable particle size of the microflocculated filler particles.

[0016] Secondly, considering that pulp contains not only anionic fibers but also a certain amount of cationic fibers and additives, this invention modifies the already micro-flocculated filler flocs with negatively charged surfaces by coating them with a modifier again. This coating layer has both positively and negatively charged functional groups, allowing for the full retention of cationic fibers, anionic fibers, and other cationic substances in the pulp. Due to the mutual adsorption of negative and positive charges on their surfaces, the functional groups of the modified filler particles form a three-dimensional, cross-functional adsorption effect, effectively increasing the three-dimensional tensile force between modified fillers and between the modified filler and pulp fibers, thus improving the shear resistance of the flocculent filler in the papermaking process.

[0017] Finally, the modified filler obtained by this invention has a particle size between 10-100 μm, an amphoteric surface, and opposite charges that attract each other, allowing the modified filler particles to fill the fiber gaps more fully and maximizing the filler content per unit volume. This effectively overcomes the problem of filler particle displacement due to gravity and vacuum suction during dewatering in existing papermaking processes, and fully and effectively retains the filler. This results in a uniform and smooth distribution of filler particles on both sides of the paper, improving the uniformity and strength of the paper, reducing surface differences, and providing a basis for lightweight, high-yield pulp, secondary fiber use, and increased ash content. It also reduces the consumption of native plant fibers, thus possessing both economic and social benefits. Attached Figure Description

[0018] Figure 1 This is a particle size distribution diagram of the micro-flocculent filler prepared in Example 1 of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] The method for preparing micro-flocculated fillers according to the present invention includes the following steps: S1: Prepare an anionic microflocculator, wherein the microflocculator comprises a first microflocculator with a molecular weight of 1-2 million, a second microflocculator with a molecular weight of 2-4 million, and a third microflocculator with a molecular weight of 4-6 million, wherein the mass ratio of the first microflocculator, the second microflocculator, and the third microflocculator is 9-16:25-33:55-65; S2: Preparation of amphoteric modifiers; S3: The micro-flocculator and modifier are added sequentially to the positive-positive filler particle suspension to obtain the micro-flocculated filler.

[0021] Step S1 includes the following details: (a) Preparation of monomers: Acrylamide, anionic monomer, and soft water are thoroughly and evenly mixed at a weight ratio of 60-70% : 25-35% : 1-8%. (ii) Preparation of the oil phase Mix the light oil and emulsifier thoroughly at a weight ratio of 85-95:5-15; (iii) Emulsification and synthesis. The monomer and oil phase are homogenized and emulsified. Under nitrogen protection, azobisisoheptanol is added at a weight ratio of 0.01-0.05%, and ammonium persulfate (diluted with soft water to a 10-20% aqueous solution) is added at a weight ratio of 0.02-0.06% to catalyze polymerization. The reaction temperature is between 40°C and 70°C to obtain the polymer. The degree of polymerization is controlled by adjusting the reaction temperature and reaction time. Specifically, the density of the reactants during the reaction is measured to obtain the first micro-flocculator (density 0.988-1.0188 g / cm³). 3 The first component has a molecular weight of 1-2 million; the second component is a micro-flocculator with a density of 1.018-1.058 g / cm³. 3 (Molecular weight 2-4 million) and third micro-flocculator (density 1.05-1.0798 g / cm³) 3 The molecular weight is 4-6 million.

[0022] (iv) Post-processing; (1) At 30-50°, a reverse agent was added to each of the above three micro-flocculators to obtain an oil-in-water anion-containing micro-flocculator. The weight ratio of the reverse agent added to the polymer was 1-3%. (2) The above micro-flocculators are mixed in order of molecular weight from large to medium to small, and in a weight ratio of 55-65:25-33:9-16 to obtain the final micro-flocculator product.

[0023] Step S2 includes the following details: (a) Preparation of monomers. Propionic amide, cationic monomer, anionic monomer and soft water are thoroughly and evenly mixed in a weight ratio of 65-75% : 9.2-29.2% : 0.3-20.3% : 1-4%. (ii) Preparation of the oil phase; The light oil and emulsifier are thoroughly mixed at a weight ratio of 90%:10%.

[0024] (III) Emulsification and Synthesis: (1) The monomer and the oil phase are thoroughly homogenized and emulsified. Under nitrogen protection, azobisisoheptanol is added at a weight ratio of 0.01-0.1%, and ammonium persulfate is added at a weight ratio of 0.01-0.1% (diluted with soft water to a 15% aqueous solution before addition). Catalytic polymerization reaction is carried out at a reaction temperature between 40-70℃ to obtain a ternary polymer.

[0025] (2) By controlling the reaction temperature and reaction time, the degree of polymerization of the reaction is controlled, and the density of the reactants during the reaction is measured to reach 0.99-1.08 g / cm³. 3 Its molecular weight is between 1 million and 8 million. This is used as the focus of the polymerization reaction to obtain the desired polymer as a modifier.

[0026] (iv) Post-processing: (1) At 30-50℃, add the reverse agent to the modifier. The amount of reverse agent added is 0.5-1.5% by weight.

[0027] (2) By controlling the addition ratio of cationic monomers to anionic monomers, terpolymers with amphoteric cationic, amphoteric anionic, and equal amphoteric properties were obtained respectively.

[0028] Step S3 includes the following details: (1) Preparation of an aqueous suspension containing positive filler particles; (2) After diluting the micro-flocculator to 0.1-0.5% online, inject it into the suspension for flocculation to obtain micro-flocculated solution; (3) After online dilution of the modifier to 0.1-0.5%, it is injected into the micro-flocculation liquid of the filler to obtain an amphoteric micro-flocculation filler suspension. The online diluted modifier can be simultaneously introduced into the swelling liquid of cationic or amphoteric starch and injected into the micro-flocculation liquid of the filler to control the median particle size of the amphoteric micro-flocculated filler particles to 30-80 μm, and the average particle size to be controlled at 40-60 μm. 80% of the particle size distribution is in the range of 20-90 μm. Its surface has amphoteric functional groups and is distributed in a narrow range.

[0029] Example 1 The steps for preparing the micro-flocculated filler in Example 1 are as follows: Step S1: (a) Preparation of monomers: Acrylamide, anionic monomer (acrylic acid monomer), and soft water were thoroughly and evenly mixed at a weight ratio of 65%:30%:5%. (ii) Preparation of the oil phase The light oil and emulsifier (the emulsifiers are span80 and tween61, with a weight ratio of 0.65:1) are thoroughly mixed at a weight ratio of 90%:10%; (iii) Emulsification and synthesis. The monomer and oil phase were homogenized and emulsified. Under nitrogen protection, azobisisoheptanol (0.03% by weight) and ammonium persulfate (diluted with soft water to a 15% aqueous solution) (0.045% by weight) were added to catalyze polymerization. The reaction temperature was controlled between 40-70℃ to obtain the polymer. The degree of polymerization was controlled by adjusting the reaction temperature and reaction time. Specifically, the density of the reactants during the reaction was measured to obtain the first micro-flocculator (density 0.99 g / cm³). 3 Its molecular weight is 1-2 million; the second micro-flocculator (density is 1.03 g / cm³) 3 (Molecular weight 2-4 million), third micro-flocculator (density 1.06 g / cm³) 3 The molecular weight is 4-6 million.

[0030] (iv) Post-processing; (1) At 40°C, a phase inversion agent (AEO-7, added at a weight ratio of 1.6%) was added to the above three micro-flocculators to obtain an oil-in-water anion-containing micro-flocculators, and a reverse agent was added to the polymer at a weight ratio of 1.8%; (2) The above micro-flocculators are mixed in order of molecular weight from large to medium to small, and in a weight ratio of 60%:28%:12% to obtain the final micro-flocculator product.

[0031] Step S2 (a) Preparation of monomers. Propionic amide, cationic monomer (acryloyloxyethyltrimethylammonium chloride), anionic monomer (acrylic acid), and soft water were thoroughly and evenly mixed in a weight ratio of 67.75%:25.9%:2.6%:3.75%. (ii) Preparation of the oil phase; The light oil and emulsifier (span80 and tween61, with a weight ratio of 0.6) are thoroughly mixed at a weight ratio of 90%:10%.

[0032] (III) Emulsification and Synthesis: (1) The monomer and the oil phase are thoroughly homogenized and emulsified. Under nitrogen protection, azobisisoheptanol is added at a weight ratio of 0.05%, and ammonium persulfate is added at a weight ratio of 0.05% (diluted with soft water to a 15% aqueous solution before addition). Catalytic polymerization reaction is carried out at a reaction temperature between 40-70℃ to obtain a ternary polymer.

[0033] (2) By controlling the reaction temperature and reaction time, the degree of polymerization of the reaction can be controlled. Specifically, the density of the reactants during the reaction process is measured to reach 1.02 g / cm3, and the molecular weight is between 6 million and 8 million, so that the desired polymer is obtained as the modifier.

[0034] (III) Post-processing: At 30-50℃, a reverse agent (AEO-7) is added to the modifier at a weight ratio of 1.0% to obtain an amphoteric terpolymer.

[0035] Step S3 includes the following details: (1) Prepare an aqueous suspension of positively charged filler particles (ground calcium carbonate: precipitated calcium carbonate = 6:4), and dilute it to 10% with water; (2) After diluting the micro-flocculator to 0.1% online, inject it into the suspension for flocculation. Add 1 kg / t of dry filler to obtain micro-flocculated solution. (3) After diluting the modifier online to 0.1%, inject it into the micro-flocculation liquid of the filler, and add 2 kg / t of oven-dry slurry to obtain an amphoteric micro-flocculation filler suspension; (4) The online diluted modifier is simultaneously introduced into the swelling solution of cationic starch (mass concentration 1.5%, dosage 3kg / t for paper making) and injected into the micro-flocculation solution of the filler. Its surface has amphoteric functional groups and is distributed in a narrow range.

[0036] The particle size analysis of the above-mentioned micro-flocculated filler particles is shown in the following results. Figure 1 As shown.

[0037] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the microflocculator in Comparative Example 1 contains only a first microflocculator with a molecular weight of 1 million to 2 million.

[0038] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the microflocculator in Comparative Example 2 contains only a second microflocculator with a molecular weight of 2-4 million.

[0039] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the microflocculator in Comparative Example 3 contains only a second microflocculator with a molecular weight of 4 million to 6 million.

[0040] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses a commercially available anionic flocculant (Nalco DEV115) instead of the microflocculator in Example 1, and uses a commercially available cationic flocculant (Nalco DEV125) instead of the modifier in Example 1.

[0041] Characterization The filler particles obtained in the above examples and comparative examples were applied to mixed papermaking, and paper was produced by a paper machine. The oven-dry ratio of filler to fiber raw material was 35%:65%, and the resulting paper had a basis weight of 75 gsm. The paper after mixed papermaking was subjected to physical property testing in a constant temperature and humidity environment. The test items were: tensile index, printing strength of the front surface, printing strength of the back surface, bursting index, longitudinal Taber stiffness, transverse Taber stiffness, transverse folding endurance, and ash content. The results are shown in Table 1. Table 1 Comparison of results between Example 1 and Comparative Examples 1-4 As can be seen from the table above, compared with Comparative Examples 1 and 2, Example 1 achieved a higher ash content while keeping other paper properties the same; compared with Comparative Examples 3 and 4, the difference between the two sides of the paper prepared in Example 1 was significantly reduced. Therefore, the micro-flocculent filler provided in Example 1 has extremely high application value.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a micro-flocculated filler for papermaking, characterized in that, Includes the following steps: S1: Prepare an anionic microflocculator, wherein the microflocculator comprises a first microflocculator with a molecular weight of 1-2 million, a second microflocculator with a molecular weight of 2-4 million, and a third microflocculator with a molecular weight of 4-6 million, wherein the mass ratio of the first microflocculator, the second microflocculator, and the third microflocculator is 9-16:25-33:55-65; S2: Preparation of amphoteric modifiers; S3: The micro-flocculator and modifier are added sequentially to the positive-positive filler particle suspension to obtain the micro-flocculated filler; Step S1 includes the following steps: (a) Preparation of monomers: Acrylamide, anionic monomer, and soft water are thoroughly and evenly mixed at a weight ratio of 60-70% : 25-35% : 1-8%. (II) Preparation of the oil phase: Mix the light oil and emulsifier thoroughly at a weight ratio of 90%:10%; (III) Emulsification and Synthesis: The monomer and oil phase are homogenized and emulsified. Under nitrogen protection, azobisisobutyronitrile (AIORT) is added at a weight ratio of 0.01-0.05%, and ammonium persulfate is added at a weight ratio of 0.02-0.06% to catalyze polymerization. The added ammonium persulfate is diluted with soft water to a 10-20% aqueous solution. The reaction temperature is between 40℃ and 70℃ to obtain the polymer. The degree of polymerization is controlled by adjusting the reaction temperature and reaction time. Specifically, the density of the reactants during the reaction is measured to obtain the first, second, and third micro-flocculators, wherein the density of the first micro-flocculator is 0.988-1.0188 g / cm³. 3 The molecular weight is 1-2 million, and the density of the second micro-flocculator is 1.018-1.058 g / cm³. 3 The molecular weight is 2-4 million, and the density of the third micro-flocculator is 1.05-1.0798 g / cm³. 3 Molecular weight is 4-6 million; (iv) Post-processing: (1) At 30-50℃, a phase inversion agent, namely AEO-7, is added to the first micro-flocculator, the second micro-flocculator and the third micro-flocculator respectively to obtain a water-in-oil anion-containing micro-flocculator. The weight ratio of the phase inversion agent added to the polymer is 1-3%. (2) The above micro-flocculators are mixed in order of molecular weight from large to medium to small, and in a weight ratio of 55-65:25-33:9-16 to obtain the final micro-flocculator product; Step S2 includes the following steps: (a) Preparation of monomers: Acrylamide, cationic monomer, anionic monomer and soft water are thoroughly and evenly mixed in a weight ratio of 65-75% : 9.2-29.2% : 0.3-20.3% : 1-4%. (ii) Preparation of the oil phase: The light oil and emulsifier are thoroughly mixed at a weight ratio of 90%:10%; (III) Emulsification and Synthesis: (1) The monomer and oil phase are thoroughly homogenized and emulsified. Under nitrogen protection, azobisisoheptanenitrile is added at a weight ratio of 0.01-0.1%, and ammonium persulfate is added at a weight ratio of 0.01-0.1%. The added ammonium persulfate is diluted with soft water to a 15% aqueous solution. Catalytic polymerization reaction is carried out at a reaction temperature between 40-70℃ to obtain a ternary polymer. (2) By controlling the reaction temperature and reaction time, the degree of polymerization of the reaction is controlled, and the density of the reactants during the reaction is measured to reach 0.99-1.08 g / cm³. 3 Its molecular weight is between 1 million and 8 million. This is used as the endpoint of the polymerization reaction to obtain the desired polymer as a modifier. (iv) Post-processing: (1) At 30-50℃, a phase inversion agent is added to the modifier, wherein the phase inversion agent is AEO-7, and the phase inversion agent is added at a weight ratio of 0.5-1.5%; (2) By controlling the addition ratio of cationic monomers to anionic monomers, an amphoteric terpolymer was obtained; Step S3 includes the following steps: (1) Preparation of an aqueous suspension containing positive filler particles; (2) After diluting the micro-flocculator to 0.1-0.5% online, inject it into the suspension for flocculation to obtain micro-flocculated solution; (3) After diluting the modifier online to 0.1-0.5%, inject it into the micro-flocculation solution obtained in step (2) to obtain an amphoteric micro-flocculation filler suspension; while diluting the modifier online, introduce the swelling solution of cationic starch and inject it into the obtained micro-flocculation solution together. The mass concentration of cationic starch is 1.5%. Control the median particle size of the amphoteric micro-flocculation filler particles to be 30-80 μm and control the average particle size to be 40-60 μm. The particle size distribution accounts for 80% of the particle size distribution to be 20-90 μm. Its surface has amphoteric functional groups. The anionic monomer used in step S1 is selected from the following compounds and their aqueous solutions: (meth)acrylic acid; the cationic monomer used in step S2 is selected from the following compounds and their aqueous solutions: dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, diallyl dimethylammonium chloride, acryloyloxyethyl trimethylammonium chloride, methacryloyloxyethyl trimethylammonium chloride, or mixtures thereof; the anionic monomer is selected from the following compounds and their aqueous solutions: (meth)acrylic acid; In step S3, the filler particles are selected from precipitated calcium carbonate, a mixture of precipitated calcium carbonate particles and ground calcium carbonate particles, and talc microparticles, and the mass concentration of the filler particles in the suspension is 10-30%.

2. A micro-flocculated filler for papermaking prepared by the preparation method according to claim 1.

3. The application of the micro-flocculated filler according to claim 2 in papermaking, characterized in that, The micro-flocculated filler is mixed with the oven-dry pulp at a ratio of 10-40:60-90, and the pulp contains cationic fibers and / or cationic additives in addition to anionic fibers.

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