JP2008063691A - Paper making method - Google Patents

Abstract

[PROBLEMS] To improve the yield of a bulking agent having a highly foaming surfactant when making a paper stock containing a bulking agent, reduce defects and paper breaks due to foaming, and provide sufficient raw materials and fillers. Providing a method for making paper efficiently by providing a good yield effect and further increasing drainage.
A method for making a paper material containing a bulking agent, wherein an anionic polymer is added to the paper material. Furthermore, a papermaking method using a cationic polymer in combination with the anionic polymer.
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Description

  The present invention relates to a paper-making method, and more particularly to a method for efficiently making a paper by increasing yield and drainage when making a stock containing a bulking agent.

In general, in a papermaking process in a paper pulp factory, it is common to use some yield improver as a method for improving the yield of raw materials and fillers. As the yield improver, a low molecular weight to high molecular weight polymer imparted with ionicity is used alone or in combination with other yield improvers. Among the polymers imparted with ionicity, cationic polymers are widely used, and among them, cationic polyacrylamides using acrylamide as a raw material are well known. A method for improving the yield of raw materials and fillers by adding cationic starch and colloidal silica to a pulp suspension as a case of using together is disclosed (for example, see Patent Document 1), and a cationic polymer is added. A method of shearing afterwards and then adding bentonite is disclosed (for example, see Patent Document 2). Furthermore, a method for improving pitch and drainage by adding a cationic polymer having a molecular weight lower than that of the main cationic polymer before adding the main cationic polymer, and finally adding an anionic inorganic substance. Is disclosed (for example, see Patent Document 3).
By the way, in recent years, attempts have been made to reduce the basis weight of various paper products by reducing the amount of pulp used when paper is manufactured, in order to reduce the manufacturing cost of paper products. Further, from the viewpoint of environmental protection and effective use of resources, there is a demand for lighter paper, and there is a demand for thick and thick paper even with a small amount of pulp. Various methods are known as methods for obtaining bulky paper, and one of them is a method using a bulking agent mainly composed of a surfactant.
However, when such a bulking agent is added to the aqueous system in the papermaking process, defects due to foaming in the aqueous system occur, production efficiency decreases due to paper breakage, and the yield of raw materials and fillers increases. Problems such as significant reduction are likely to occur.
However, the conventional technique has a problem that a sufficiently satisfactory effect cannot be obtained in the yield of raw materials and fillers in an aqueous system using a bulking agent.
Further, when bentonite is used, it takes time to dissolve. In addition, when colloidal silica is used, the concentration of the active ingredient is low, so that the transportation cost is high, and further, a silica scale is generated at the addition point, and the paper quality is deteriorated.
U.S. Pat. No. 4,388,150 Japanese Patent Laid-Open No. 62-191598 Japanese Patent Publication No. 5-29719

  Under such circumstances, the present invention improves the yield of a bulking agent having a highly foaming surfactant when making a paper stock containing a bulking agent, and causes defects and paper breakage due to foaming. The purpose of the present invention is to provide a method for producing paper efficiently by exhibiting a sufficient yield effect of raw materials and fillers and further increasing drainage.

As a result of intensive studies to achieve the above object, the present inventor has found that the object can be achieved by adding an anionic polymer to a paper stock containing a bulking agent. Based on this, the present invention has been achieved.
That is, the present invention
[1] A method for making a paper material containing a bulking agent, wherein an anionic polymer is added to the paper material,
[2] A water-soluble or water-dispersible polymer in which the anionic polymer has at least one anionic group selected from free, salt-type carboxyl groups, sulfone groups, and phosphate groups in the molecule. The paper making method according to item [1] above,
[3] The papermaking method according to the above [1] or [2], wherein the addition amount of the anionic polymer is 0.002 to 0.5% by mass relative to the solid content of the paper stock,
[4] The papermaking method according to any one of [1] to [3] above, wherein the cationic polymer is used in combination with the anionic polymer.
[5] The cationic polymer has an intrinsic viscosity of 15 dl / g or less and a cation equivalent of 0.5 measured in a 1 mol / L sodium nitrate aqueous solution or a 1 mol / L sodium chloride aqueous solution. The papermaking method described in the above item [4], which is a polymer in the range of ˜11 meq / g, and [6] the addition amount of the cationic polymer are 0.002 to 0 based on the solid content of the stock. The papermaking method according to [4] or [5] above, which is .5% by mass;
Is to provide.

According to the present invention, when making a stock containing a bulking agent, the yield of the bulking agent having a highly foaming surfactant is improved, and defects and paper breaks due to foaming are reduced, and the raw materials and A sufficient yield effect of the filler can be exhibited, and a method of efficiently making paper by increasing drainage can be provided.
Moreover, the yield of a raw material and a filler can be raised and the bulky paper can be produced stably, without changing the density of paper in the aqueous system which uses the bulking agent. Furthermore, the labor for dissolving the bulking agent can be saved, and since the active ingredient concentration is high, the transportation cost can be kept low. Moreover, the polymer used as a bulking agent is an organic substance, and there is no generation | occurrence | production of the scale at an addition point.

The papermaking method of the present invention is a method for making a paper stock containing a bulking agent, wherein an anionic polymer is added to the stock.
In the present invention, the bulking agent contained in the paper stock is a kind of surfactant, and by using this in the paper making process of the paper, the pulp surface becomes hydrophobic and there are many voids between the pulp layers, resulting in a light and thick paper. it can.
Such bulking agents are not particularly limited, and conventionally known bulking agents such as additives comprising polyoxyalkylene adducts of fatty acids and fatty acid esters; fats and oils or sugar alcohol-based nonionic surfactants; quaternary ammonium salts, Additives combining alkylamine and betaine type amphoteric surfactants and nonionic surfactants; Additives containing di-long chain alkyl type quaternary ammonium salts; Dialkyl quaternary ammonium salts and glycerin and water or carbon number 4 The following additives containing aliphatic alcohols; additives containing lanolin and lanolin derivatives; additives containing polyamide derivatives; and the like can be used.

Moreover, there is no restriction | limiting in particular in the said paper stock, What contains the various chemicals generally used in a papermaking process including raw material pulp can be mentioned.
Examples of the raw material pulp include chemical pulp (conifer or hardwood bleached or unbleached kraft pulp), mechanical pulp (ground pulp, thermomechanical pulp, chemithermomechanical pulp, etc.), deinked pulp (newspaper, magazine waste paper, etc.) Etc. can be selected singly or in any proportion.
Examples of various agents include paper strength enhancers such as polyacrylamide and plant guam, sizing agents such as alkyl ketene dimers and rosins, drainage and retention improvers such as polyethyleneimine and cationized polymers, sulfate bands, sodium chloride In addition, an internal additive such as sodium aluminate, polyvinyl alcohol, and latex can be used in combination. Furthermore, additives such as a pitch control agent and a slime control agent can be used in combination depending on the application.

In the present invention, the anionic polymer added to the stock containing the bulking agent is at least one selected from free or salt-type carboxyl group, sulfone group and phosphate group in the molecule. A water-soluble or water-dispersible polymer having an anionic group can be used.
Examples of such an anionic polymer include (meth) acrylic acid polymers and salts thereof, copolymers having acrylamide units and (meth) acrylic acid units, and salts thereof. As the salt, an alkali metal salt is preferable, and a sodium salt is preferable from an industrial aspect.
Preferable examples of the anionic polymer include acrylamide / sodium acrylate copolymer, acrylamide / sodium acrylamidomethylpropanesulfonate / sodium acrylate copolymer, and the like.
The anionic polymer used in the present invention may be a linear polymer or a crosslinked or branched polymer. Furthermore, as described in Japanese Patent No. 2948358, when cross-linked, the diameter is smaller than about 750 nm, and when non-cross-linked and insoluble, the diameter is smaller than 60 nm, corresponding to the anion of fine particles. An anionic organic polymer fine particle polymer having an amount of 0.1 meq / g or more can also be preferably used.
These anionic polymer polymers may be used individually by 1 type, and may be used in combination of 2 or more type.

In the present invention, a cationic polymer can be used in combination with the anionic polymer.
The cationic polymer that can be used in combination is not particularly limited in its monomer component, but the intrinsic viscosity (if precipitation occurs in an aqueous solution of sodium nitrate of 1 mol / L concentration, 1 mol / L concentration) Those having physical properties of an intrinsic viscosity (in saline) of 15 dl / g or less and a cation equivalent of 0.5 to 11 meq / g are preferred. When the intrinsic viscosity exceeds 15 dl / g, the molecular weight tends to be too large and weak against shearing, and when the cation equivalent is less than 0.5 meq / g, the floc-forming effect is hardly exhibited, while 11 meq / g is reduced. When it exceeds, there exists a tendency which reacts strongly and an aggregate is formed.
Specific examples of this cationic polymer include: polyethyleneimine; condensate of polyethyleneimine and epichlorohydrin; homopolymer of dicyanamide; dimethyldiallylamine ammonium chloride and (meth) acryloyloxyethyltrimethylammonium chloride. Homopolymers; and copolymers of these with acrylamide. These cationic polymer polymers may be used individually by 1 type, and may be used in combination of 2 or more type.
When the cationic polymer is used in combination, the cationic polymer is first added using the pulp suspension to which the bulking agent is added as a paper stock. The addition amount of the cationic polymer is about 0.002 to 0.5% by mass with respect to the solid content of the paper stock. The anionic polymer is preferably added after the cationic polymer is added. A preferable addition amount is about 0.002 to 0.5% by mass with respect to the solid content of the paper stock. It is desirable to add more than the lower limit of the above-mentioned addition amount in order to exhibit a sufficient yield effect for both the cationic polymer and the anionic polymer, and to make the formation good, the upper limit of the above-mentioned addition amount and below It is preferable to do.
In the present invention, the anionic polymer polymer or the anionic polymer polymer and the cationic polymer polymer added to the stock containing the bulking agent may be a long net paper machine, a twin wire machine, a Yankee machine, etc. It can be used in any paper machine and can be added to the stock in processes such as mixing tests, machine chests and seed boxes.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, preparation of a test sample and a test method are shown below.
(1) Preparation of test sample To 100% LBKP (hardwood bleached kraft pulp) pulp sample, cationic starch [manufactured by Nippon Food Processing Co., Ltd., trade name "Neotac 40T"] vs. dry pulp 0.8 mass%, aluminum sulfate 1.5% by weight of dry pulp, 0.02% by weight of ASA (alkenyl succinic anhydride) sizing agent and 0.02% by weight of paper strength agent (trade name “Harmide EX234”, manufactured by Harima Kasei Co., Ltd.) 5% by mass, bulking agent [trade name “KB-115” manufactured by Kao Corporation] as a solid content, 1.0% by mass to dry pulp is added, and the slurry concentration is 0.47% by mass, A sample sample was prepared by adding 38% by mass of calcium carbonate to SS.
This sample sample was SS (suspended substance): 4671 mg / L, ash: 1776 mg / L, pH: 7.3, CD (cation requirement): 5 μeq / L.
(2) Test method (a) Yield rate measurement After adding 1000 mL of the test sample prepared in (1) above to a yield tester [Mutech, model name “DFS”] and adding various yield improvers The concentrations of SS and ash in the collected filtrate were measured, and the yield was calculated according to the following formula.
Yield rate (%) = [1− (SS or ash concentration in filtrate / SS or ash concentration in test sample)] × 100
(B) Tension, basis weight and thickness of the paper made after adding various yield improvers to the test sample prepared in (1) above, weigh the sheet so that the basis weight after paper making becomes 70 g / m ^2. After stirring, a sheet was obtained by making paper with an 80-mesh wire using a square tappi paper machine. The sheet after paper making was pressed with a press at 34.3 N / cm ² for 2 minutes, and then dried at 105 ° C. for 1 minute using a mirror dryer.
The dried sheet was conditioned at 23 ° C. and a relative humidity of 50% for 1 day, and then bulkiness was determined.
The tenacity represents the bulkiness of the paper. The basis weight (g / m ² ) and thickness (mm) of the paper are measured, and the tenacity (g / cm ³ ) is calculated from the basis weight / thickness by the following formula. I asked more.
Tension (g / cm ³ ) = [basis weight of paper (g / m ² ) / thickness (mm)] × 10 ⁻³
The smaller the value, the higher the bulk, and a difference of 0.02 is recognized as a significant difference. The basis weight is obtained in accordance with JIS P 8124, and the thickness is obtained by superposing four sheets of the obtained paper, and the thicknesses of 10 places differing depending on the JIS paper thickness measuring machine [manufactured by Japan TMC, model name “PEACOCK”]. It measured and calculated | required from the average value.

Examples 1-9 and Comparative Examples 1-4
The yield improver shown in Table 1 was added to the test sample prepared in (1) in the amount shown in Table 1, and various properties were determined according to the test methods described above. The results are shown in Table 1.

[note]
1) Anionic polymer 1: linear anionic polymer, AAm / AANa (molar ratio 90:10) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 1.4 meq / g
2) Anionic polymer 2: linear anionic polymer, AAm / AANa (molar ratio 80:20) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 2.6 meq / g
3) Anionic polymer 3: linear anionic polymer, AAm / AANa (molar ratio 60:40) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 5.0 meq / g
4) Anionic polymer 4: linear anionic polymer, AAm / AANa (molar ratio 50:50) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 6.1 meq / g
5) Anionic polymer 5: linear anionic polymer, AAm / AANa (molar ratio 40:60) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 7.1 meq / g
6) Anionic polymer 6: linear anionic polymer, AAm / AANa (molar ratio 30:70) copolymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 8.0 meq / g
7) Anionic polymer 7: linear anionic polymer, AAm / AMPS / AANa copolymer, intrinsic viscosity = 18 dl / g, cation equivalent = 0, anion equivalent = 0.9 meq / g
8) High holder c503: anionic organic polymer fine particle (crosslinked structure) polymer, [manufactured by Kurita Kogyo Co., Ltd., AAm / AANa copolymer], intrinsic viscosity = 3.5 dl / g, cation equivalent = 0, anion equivalent = 8 0.0 meq / g
9) Cationic polymer: linear cationic polymer, AAm / DAA copolymer, intrinsic viscosity = 12 dl / g, cation equivalent = 3 meq / g, anion equivalent = 0
10) Nonionic polymer: linear nonionic polymer, AAm polymer, intrinsic viscosity = 20 dl / g, cation equivalent = 0, anion equivalent = 0
11) Bentonite: Anionic swelling bentonite which is an anionic inorganic fine particle [product name “Hydrocol O” manufactured by Ciba Specialty Chemicals Co., Ltd.]
12) Colloidal silica: anionic inorganic fine particles [manufactured by Eka Chemicals, trade name “NP-442”]
AAm means acrylamide, AAAa means sodium acrylate, DAA means dimethylaminoethyl acrylate, and AMPS means sodium acrylamidomethylpropanesulfonate.
As can be seen from Table 1, the examples using the anionic polymer and the anionic organic fine particle polymer as the yield improver were compared with the comparative example using the nonionic polymer and the anionic inorganic fine particle. Yield rate is improved without increasing.

  The paper making method of the present invention can efficiently make paper by increasing the yield and drainage when making a paper stock containing a bulking agent.

Claims (6)

  A method for making a paper containing a bulking agent, wherein an anionic polymer is added to the paper.   The anionic polymer is a water-soluble or water-dispersible polymer having at least one anionic group selected from free, salt-type carboxyl groups, sulfone groups and phosphate groups in the molecule. Item 2. The papermaking method according to Item 1.   The papermaking method according to claim 1 or 2, wherein the addition amount of the anionic polymer is 0.002 to 0.5 mass% with respect to the solid content of the paper.   The papermaking method according to any one of claims 1 to 3, wherein the cationic polymer is used in combination with the anionic polymer.   The cationic polymer has an intrinsic viscosity of 15 dl / g or less and a cation equivalent of 0.5 to 11 meq / g measured in a 1 mol / L sodium nitrate aqueous solution or a 1 mol / L sodium chloride aqueous solution. The papermaking method according to claim 4, which is a polymer in the range of g.   The papermaking method according to claim 4 or 5, wherein the addition amount of the cationic polymer is 0.002 to 0.5 mass% with respect to the solid content of the stock.