JP2014148770A - Papermaking additive, method for producing papermaking additive, and method for producing paper - Google Patents

Abstract

The present invention provides an additive for papermaking that can improve drainage without causing a decrease in the formation of paper products and an increase in cost.
A 1N NaCl aqueous solution at 30 ° C. obtained by polymerizing a monomer component containing a cationic vinyl monomer represented by the specific formula and a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer. A cationic polymer having an intrinsic viscosity of 8 dl / g or more and an anionic polymer having a weight average molecular weight of 20000 or less, and the anionic polymer 0.0001-0 with respect to 100 parts by mass of the cationic polymer. Additive for papermaking contained in a ratio of 0.01 parts by mass.
[Selection figure] None

Description

  The present invention relates to a papermaking additive, a method for producing a papermaking additive, and a method for producing paper. More specifically, the present invention relates to a papermaking additive suitably used as a freeness improver.

  Conventionally, various paper additives such as a paper strength enhancer, a sizing agent, and a yield drainage improver have been used in a papermaking process for producing paper. In particular, in the paper industry, additives (yield / drainage improvers) that improve drainage and / or yield are used from the viewpoint of saving papermaking raw materials and improving papermaking efficiency and quality. There are many.

  For example, Patent Document 1 describes a method of improving yield by adding cationic starch and colloidal silica to a paper material before dehydration. Patent Document 2 also describes that a first synthetic cationic polymer is added before a specific shearing step and bentonite after the shearing step in order to improve drainage, retention, drying and formation characteristics. A method of adding is disclosed. Further, Patent Document 3 discloses a yield improving method in which a cationic polymer and anionic polymer fine particles are contained in a paper stock.

  On the other hand, when the amount of the polymer added to the paper stock is increased, there may be a problem that the formation of the product is lowered or the cost is increased. For such a problem, Patent Document 4 discloses a dual system in which a crosslinked polymer and bentonite are used in combination. Patent Document 5 discloses that polymerization of a monomer aqueous solution is started under the conditions of free radical polymerization to form a polymerization reaction solution, and after the monomer polymerization has progressed 30% or more, one or more structural modifiers are added to the polymerization reaction solution. In addition to the above, modified structurally modified polymers are disclosed.

  Furthermore, for the purpose of causing a polymer and pulp fiber to react strongly, Patent Document 6 proposes a method of using a cationic polymer and an anionic polymer together, and Patent Document 7 discloses a cationic monomer and an anionic property. An amphoteric polymer having a monomer as a component has been proposed. In addition, in the polymers as disclosed in Patent Document 6 and Patent Document 7, since the reaction between the cation group and the anion group in the polymer occurs strongly, the polymer itself precipitates and reacts efficiently with the pulp fiber. However, there are problems such as causing stains and greatly increasing the required concentration of addition.

US Patent No. 4,388,150 Japanese Patent Laid-Open No. 62-191598 Japanese Patent No. 2948358 Special Table 2002-518609 Japanese translation of PCT publication No. 2004-502802 Japanese Patent No. 3549330 Japanese Patent No. 3219007

  In recent years, in the paper manufacturing industry, there are increasing opportunities to use waste paper from the viewpoint of waste reduction and countermeasures against global warming. However, as the use of waste paper increases as a raw material for papermaking, the raw material situation gets worse and further improvements in drainage and yield are desired.

  Therefore, the main object of the present invention is to provide an additive for papermaking that can improve drainage with a relatively small addition amount, and thus without causing problems of lowering the formation of paper products and increasing costs. To do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have achieved an excellent drainage improvement effect by using a paper additive containing a specific cationic polymer and a specific anionic polymer in a specific ratio. As a result, the present invention has been completed.

  That is, the present invention is obtained by polymerizing a monomer component containing a cationic vinyl monomer represented by the following general formula (I) and a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer. A cationic polymer having an intrinsic viscosity of 8 dl / g or more in a 1N NaCl aqueous solution at 0 ° C. and an anionic polymer having a weight average molecular weight of 20000 or less, based on 100 parts by mass of the cationic polymer. Provided is a papermaking additive contained at a ratio of 0.0001 to 0.01 parts by mass.

  The present invention also provides a cationic vinyl monomer represented by the general formula (I) and a nonionic vinyl copolymerizable with the cationic vinyl monomer in a solution of an anionic polymer having a weight average molecular weight of 20000 or less. A polymer mixture obtained by polymerizing a monomer component including a monomer to obtain a cationic polymer, wherein the ratio of the cationic polymer to the anionic polymer is 100 parts by mass of the cationic polymer; Provided is an additive for papermaking which is 0.0001 to 0.01 part by mass and has an intrinsic viscosity of 8 dl / g or more in a 1 N NaCl aqueous solution at 30 ° C.

In the additive for papermaking of the present invention, as the cationic vinyl monomer, for example, (meth) acryloyloxyalkylammonium salt can be used. Moreover, as said nonionic vinyl monomer, (meth) acrylamide can be used, for example.
As the anionic polymer, for example, poly (meth) acrylic acid and / or poly (meth) acrylate can be used.
In the present disclosure, the description “(meth) acryl” means both “acryl” and “methacryl”.

  Further, the present invention provides a cationic vinyl monomer represented by the above general formula (I) and a nonionic property copolymerizable with the cationic vinyl monomer in a solution of an anionic polymer having a weight average molecular weight of 20000 or less. In synthesizing a cationic polymer by polymerizing a monomer component containing a vinyl monomer, the ratio of the cationic polymer to the anionic polymer is such that the anionic polymer is 0.1. Provided is a method for producing a papermaking additive, which synthesizes a cationic polymer so that the intrinsic viscosity in a 1N NaCl aqueous solution at 30 ° C. is 0001 to 0.01 parts by mass and 8 dl / g or more. .

  Furthermore, the present invention provides a paper manufacturing method in which the papermaking additive of the present invention is added to a stock.

The present invention is also obtained by polymerizing a monomer component containing a cationic vinyl monomer represented by the above general formula (I) and a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer. A cationic polymer having an intrinsic viscosity of 8 dl / g or more in a 1N NaCl aqueous solution and an anionic polymer having a weight average molecular weight of 20000 or less, based on 100 parts by mass of the cationic polymer, the anionic polymer 0 Also provided is a method for producing paper that is added to the stock at a rate of 0.0001 to 0.01 parts by weight.
The “paper” produced in the present invention includes paperboard.

  According to the additive for papermaking of the present invention, the drainage can be improved with a relatively small amount of addition, and without causing problems of lowering the formation of the product and increasing the cost.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

The paper additive of the present invention has a cationic polymer obtained by copolymerizing a cationic vinyl monomer represented by the following general formula (I) and a nonionic vinyl monomer, and a weight average molecular weight of 20000 or less. Anionic polymer. Here, the ratio of the cationic polymer to the anionic polymer is 0.0001 to 0.01 part by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer.
The cationic polymer has an intrinsic viscosity of 8 dl / g or more in a 1N NaCl aqueous solution at 30 ° C. (see the first embodiment described later), or is synthesized in a solution of an anionic polymer (described later). Of the second embodiment).

The papermaking additive as the first aspect of the present invention includes a cationic vinyl monomer represented by the following general formula (I), and a monomer containing a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer A cationic polymer having an intrinsic viscosity of 8 dl / g or more in a 1N NaCl aqueous solution at 30 ° C. and an anionic polymer having a weight average molecular weight of 20000 or less, obtained by polymerizing the components, To do.
And the additive for papermaking of this invention contains the said cationic polymer and the said anionic polymer in the ratio of 0.0001-0.01 mass part of anionic polymers with respect to 100 mass parts of cationic polymers. It is characterized by that.

In the above general formula (I), R ¹ is H or CH ₃ , A is O or NH, R ² is an alkyl group having 2 to 4 carbon atoms which may have a hydroxyl group as a substituent. R ³ is H or an alkyl group having 1 to 3 carbon atoms, R ⁴ is H, an alkyl group having 1 to 3 carbon atoms which may have a hydroxyl group as a substituent, or a benzyl group. , X ⁻ represents a halogen ion, a sulfonate ion, a methyl sulfate ion, or a hydroxide ion.

As the cationic vinyl monomer constituting the monomer component that is a raw material of the cationic polymer, the compound represented by the above general formula (I) can be used.
In the general formula (I), R ¹ is more preferably H, and A is more preferably O. R ² is more preferably an alkyl group having 2 to 4 carbon atoms (having no substituent), and more preferably an ethyl group. The R ^3, more preferably an alkyl group having 1 to 3 carbon atoms, more preferably methyl group. R ⁴ is more preferably H or an alkyl group having 1 to 3 carbon atoms (having no substituent), and more preferably a methyl group. X ⁻ is more preferably a halogen ion, and even more preferably a chloride ion.

Examples of the cationic vinyl monomer represented by the general formula (I) include dialkylaminoalkyl (meth) acrylates such as diethylaminoethyl (meth) acrylate, quaternary salts and acid salts thereof, and dialkylamino Mention may be made of alkyl (meth) acrylamides, quaternary salts and acid salts thereof.
Although it does not specifically limit as a (meth) acrylic-acid dialkylaminoalkyl and its quaternary salt and acid salt, For example, dimethylaminoethyl acrylate methyl chloride quaternary salt, dimethylaminoethyl benzyl chloride quaternary salt, acrylic acid Examples thereof include dimethylaminoethyl hydrochloride, dimethylaminoethyl methacrylate methyl chloride quaternary salt, dimethylaminoethyl methacrylate benzyl chloride quaternary salt, and dimethylaminoethyl methacrylate hydrochloride.
Dialkylaminoalkyl (meth) acrylamides and quaternary salts and acid salts thereof are not particularly limited, and examples thereof include acrylamidopropyltrimethylammonium chloride, dimethylaminopropylacrylamide hydrochloride, methacrylamidopropyltrimethylammonium chloride, and dimethylaminopropyl. Examples include methacrylamide hydrochloride.
One or two or more of these cationic vinyl monomers can be used.
As the cationic vinyl monomer, for example, a (meth) acrylic acid dialkylaminoalkyl quaternary salt is suitable. Among them, (meth) acrylic acid dimethylaminoethyl methyl chloride quaternary salt is preferred, and acryloyloxyethyltrimethylammonium chloride is preferred. Is more preferable.

The nonionic vinyl monomer constituting the monomer component that is a raw material of the cationic polymer is not particularly limited as long as it is copolymerizable with the cationic vinyl monomer.
Nonionic vinyl monomers include, for example, water-soluble (meth) acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N-methylolacrylamide, and diacetone acrylamide. Some N-substituted lower alkyl acrylamides, methacrylonitrile, acrylonitrile, alkyl acrylates, hydroxy acrylates, vinyl acetate, and the like. Among these, for example, (meth) acrylamide is preferable, and acrylamide is more preferable.
1 type (s) or 2 or more types can be used for a nonionic vinyl monomer.

The monomer component used as the raw material of the cationic polymer may contain a crosslinkable vinyl monomer in addition to the cationic vinyl monomer and the nonionic vinyl monomer.
The crosslinkable vinyl monomer brings a branched structure to the cationic polymer, and a monomer having two or more double bonds in one molecule can be used.

Typical preferred cross-linkable vinyl monomers include N, N-methylenebisacrylamide, N, N-methylenebismethacrylamide, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol diacrylate, triethylene glycol dimethacrylate. And polyethylene glycol dimethacrylate. Of these, N, N-methylenebisacrylamide is preferred.
These crosslinkable vinyl monomers may be used alone or in combination of two or more.

  The method for producing the cationic polymer is not particularly limited as long as it is radical polymerization, and can be selected as necessary, such as aqueous solution polymerization, suspension polymerization, and emulsion polymerization.

The polymerization initiator used in radical polymerization is not particularly limited, but is preferably water-soluble. Examples of the polymerization initiator include persulfate-based and peroxide-based compounds such as ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, and tert-butyl peroxide.
A polymerization initiator may be used individually by 1 type, or may use 2 or more types together, but it is preferable to use 1 type independently. A polymerization initiator may be used as a redox polymerization initiator in combination with a reducing agent. Examples of the reducing agent in this case include sulfite, sulfite and hydrogen sulfite, low ionic salt such as iron, copper and cobalt, and organic amine such as N, N, N ′, N′-tetramethylethylenediamine. Furthermore, reducing sugars such as aldose and ketose can be mentioned.

  An azo compound can also be used as a polymerization initiator. Examples of the azo compound include 2,2′-azobis-2-methylpropionamidine hydrochloride, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-N, N′-di. Methyleneisobutylamidine hydrochloride, 2,2′-azobis-2-methyl-N- (2-hydroxyethyl) -propionamide, 2,2′-azobis-2- (2-imidazolin-2-yl) -propane and The salt etc. can be used. These azo compounds may be used alone or in combination of two or more.

In synthesizing the cationic polymer, a chain transfer agent may be used to adjust the molecular weight of the cationic polymer to be synthesized.
The chain transfer agent is not particularly limited, and examples of typical chain transfer agents include alcohols, sulfur compounds, carboxylic acids and salts thereof, phosphate phosphates such as sodium hypophosphite, and combinations thereof. Can be mentioned.
Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, butyl alcohol, and glycerol. Among these, 2-propanol is preferable.
Examples of the sulfurized compound include sulfonic acid compounds such as alkylthiol, thiourea, sulfite, and disulfide. Among these, one or more selected from the group consisting of ethanethiol, thiourea, and sodium bisulfite. Is preferred.
Examples of the carboxylic acid and its salt include formic acid, malic acid, and salts thereof, and among these, one or more selected from formic acid and its salt are preferable.
As these chain transfer agents, it is more preferable to use sodium hypophosphite and / or sodium formate.

As a polymerization method of the cationic polymer, there is a batch polymerization method in which all the monomer components that are the raw materials of the cationic polymer are charged in a reaction vessel in a batch and polymerized. In this case, the polymerization initiator is polymerized. It may be added to the vessel in advance or at the time of polymerization, and may be supplied continuously or intermittently during the polymerization. When supplying at the time of superposition | polymerization, an addition rate can be changed as needed.
The polymerization temperature when synthesizing the cationic polymer is generally 30 to 100 ° C. when a single polymerization initiator is used, and is lower in the case of a redox polymerization initiator, generally 5 to 90 ° C. The polymerization temperature may be kept constant or varied during the polymerization, and cooling and heating can be performed as necessary.
The atmosphere in the polymerization vessel is not particularly limited, but it is preferable to substitute with an inert gas such as nitrogen gas in order to carry out the polymerization quickly.

The cationic polymer obtained by polymerizing the monomer component containing the cationic vinyl monomer represented by the general formula (I) and the nonionic vinyl monomer has an intrinsic viscosity in a 1N NaCl aqueous solution at 30 ° C. , Which may be abbreviated as “intrinsic viscosity”) is 8 dl / g or more. When the intrinsic viscosity of the cationic polymer is 8 dl / g or more, the cationic polymer has a high molecular weight and a high cohesive force.
The upper limit of the intrinsic viscosity of the cationic polymer is not particularly limited, but in consideration of the cationic polymer that can be actually produced, it is about 20 dl / g or less. The range of the intrinsic viscosity of the cationic polymer is preferably 8 to 20 dl / g, more preferably 9 to 20 dl / g, and still more preferably 10 to 20 dl / g.

  In the present disclosure, the “intrinsic viscosity” is a value calculated using a Huggins equation and a Mead-Fuoss equation from the measured value by measuring the flow time using a Canon Fenceke viscometer. .

  The cationic polymer is preferably water-soluble. The molecular structure of the cationic polymer may be either a linear structure or a branched structure.

  The ratio of the cationic vinyl monomer and nonionic vinyl monomer used as the raw material for the cationic polymer can be arbitrarily selected according to the water quality to be treated. For example, the molar ratio of the cationic vinyl monomer: nonionic vinyl monomer is preferably 5:95 to 95: 5, more preferably 5:95 to 50:50, and still more preferably 5:95 to 35:65.

When the above-mentioned crosslinkable vinyl monomer is used in the synthesis of the cationic polymer, the introduction ratio of the crosslinkable vinyl monomer is 5.0 × with respect to all monomers of the monomer component that is the raw material of the cationic polymer. 10 ⁻³ mol% or less is preferable, and 2.0 × 10 ⁻³ mol% or less is more preferable. When the introduction ratio of the crosslinkable vinyl monomer is within the above range, the cationic polymer is hardly insolubilized, and a cationic polymer having an intrinsic viscosity of 8 dl / g or more is easily obtained.

The additive for papermaking of this invention contains the anionic polymer whose weight average molecular weight is 20000 or less with a cationic polymer.
In the present invention, poly (meth) acrylic acid and / or poly (meth) acrylate is used as the anionic polymer. As a salt of poly (meth) acrylate, sodium is preferable. Of poly (meth) acrylic acid and poly (meth) acrylate, polyacrylic acid and sodium polyacrylate are preferable, and sodium polyacrylate is more preferable.

  Such an anionic polymer can be produced by polymerizing (meth) acrylic acid and / or (meth) acrylate, and a commercially available product can also be used.

The weight average molecular weight of the anionic polymer used in the papermaking additive of the present invention is 20000 or less. The lower limit of the weight average molecular weight is not particularly limited, but is preferably 2000 or more.
The weight average molecular weight of the anionic polymer is preferably 2000 to 20000, more preferably 3000 to 15000, and still more preferably 4000 to 10,000.
The weight average molecular weight can be measured by a general method such as GPC method and light scattering method.

  Polyacrylic acid and sodium polyacrylate, which are suitable as an anionic polymer, are strong anionic, so when the weight average molecular weight exceeds 20000, it is easy to form a very strong polyion complex with a cationic polymer, and a precipitate is formed. There is a case. Therefore, when a strong anionic polymer is used, its weight average molecular weight and the blending ratio or mixing ratio (ratio of cationic polymer and anionic polymer) described later are important.

The additive for papermaking of this invention contains the said cationic polymer and the said anionic polymer in the ratio of 0.0001-0.01 mass part of anionic polymers with respect to 100 mass parts of cationic polymers.
In the papermaking additive of the present invention, a cationic polymer and an anionic polymer are used together at a ratio of the anionic polymer to the cationic polymer of 10 ⁻⁴ to 10 ⁻² mass%.
By combining the cationic polymer and the anionic polymer in the above ratio, a synergistic effect is achieved by the combined use of both polymers, and a precipitate (polyion complex) due to the reaction between the cationic polymer and the anionic polymer is produced. It becomes difficult to produce | generate, As a result, it becomes possible to raise the density | concentration of an active ingredient.

  Precipitation due to reaction of the cationic polymer and the anionic polymer when the anionic polymer exceeds 0.01 part by mass with respect to 100 parts by mass of the cationic polymer (the mass ratio of the anionic polymer to the cationic polymer is 0.01% by mass) A product (polyion complex) is easily generated, and the concentration of the active ingredient is lowered. In addition, when the amount of the anionic polymer is less than 0.0001 parts by weight (the weight ratio of the anionic polymer to the cationic polymer is 0.0001% by weight) with respect to 100 parts by weight of the cationic polymer, the amount of the anionic polymer is too small. And an anionic polymer in combination are less effective.

  In the paper additive of the first aspect of the present invention after mixing the cationic polymer and the anionic polymer, the range of the intrinsic viscosity is not particularly limited, but is preferably 8 to 20 dl / g.

  The additive for papermaking of the present invention includes, for example, a step of synthesizing a cationic polymer separately from an anionic polymer as described above, and anionic polymer 0.0001 to 0.01 mass with respect to 100 parts by mass of the cationic polymer. It can manufacture by performing the process of mixing a cationic polymer and an anionic polymer in the ratio of a part.

  Mixing of the cationic polymer and the anionic polymer may be performed in the form (for example, powder, emulsion, liquid, etc.) when the cationic polymer and the anionic polymer are respectively synthesized. Alternatively, a solution may be prepared after mixing the cationic polymer and the anionic polymer. Each polymer in each form is dissolved separately, and then each solution is mixed to form one solution. It may be added to the paper pulp slurry. In this case, the polymer mixture of the cationic polymer and the anionic polymer preferably has an intrinsic viscosity of 8 dl / g or more in a 1N NaCl aqueous solution at 30 ° C., and preferably 8 dl / g to 20 dl / g. .

Next, the papermaking additive according to the second aspect of the present invention will be described.
A papermaking additive as a second aspect of the present invention uses a polymer mixture containing an anionic polymer and a cationic polymer obtained by synthesizing a cationic polymer in a solution of the anionic polymer. It is.
That is, the additive for papermaking according to the second aspect of the present invention comprises a single amount containing the cationic vinyl monomer represented by the general formula (I) and the nonionic vinyl monomer in the solution of the anionic polymer. It contains a polymer mixture that polymerizes body components to obtain a cationic polymer. Further, the paper additive containing the polymer mixture includes a cationic polymer and an anionic polymer in a ratio of 0.0001 to 0.01 part by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer. And an intrinsic viscosity in a 1N NaCl aqueous solution at 30 ° C. is 8 dl / g or more.

  Cationic vinyl monomers, nonionic vinyl monomers and crosslinkable vinyl monomers as monomer components used as raw materials for cationic polymers, polymerization initiators and chain transfer agents that can be used in the synthesis of cationic polymers, and anionic properties The polymer is the same as that described in the description of the paper additive as the first aspect of the present invention.

  The upper limit of the intrinsic viscosity of the polymer mixture is not particularly limited, but is preferably 20 dl / g or less from the viewpoint of actual production. The range of the intrinsic viscosity of the polymer mixture is preferably 8 to 20 dl / g, more preferably 9 to 20 dl / g, and still more preferably 10 to 20 dl / g.

  The solvent for preparing the anionic polymer solution is not particularly limited. For example, water can be used, and an aqueous solution obtained by diluting and dissolving the anionic polymer can be used as the anionic polymer solution. In this case, the concentration of the anionic polymer in the solution of the anionic polymer is not particularly limited, but is preferably 0.0001 to 0.5% by mass, for example, 0.001 to 0.1% by mass. It is more preferable.

  The additive for papermaking of the present invention is a ratio of 0.0001 to 0.01 part by weight of anionic polymer with respect to 100 parts by weight of cationic polymer in synthesizing the cationic polymer in the solution of the anionic polymer. And a method of synthesizing a cationic polymer so that the intrinsic viscosity in a 1N NaCl aqueous solution at 30 ° C. is 8 dl / g or more. For example, by adjusting the addition amount of the polymerization initiator used when synthesizing the cationic polymer, it is possible to give the obtained papermaking additive a desired intrinsic viscosity.

In this method for producing a paper additive, a cationic polymer is synthesized in a solution of an anionic polymer, and therefore, the cationic polymer and the anionic polymer are mixed together with the synthesis of the cationic polymer, resulting in high efficiency. The additive for papermaking can be manufactured.
Furthermore, by adopting the method for producing a paper additive of the present invention at the site of the paper making process, the production of the paper additive and the paper making can be performed consistently, and the paper can be efficiently produced. It becomes possible.

  In the method for producing paper of the present invention, the cationic polymer and the anionic polymer are added to the paper stock at a ratio of 0.0001 to 0.01 part by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer. Features. Thereafter, paper is manufactured through a manufacturing process conventionally performed in the paper industry such as dehydration and drying.

  The cationic polymer and the anionic polymer can be blended with the separately synthesized cationic polymer and anionic polymer and added to the paper stock as the papermaking additive of the first aspect of the present invention described above.

  In addition, the cationic polymer and the anionic polymer are synthesized according to the second aspect of the present invention described above using a polymer mixture containing both polymers obtained by synthesizing the cationic polymer in a solution of the anionic polymer. It can also be added to the stock as a papermaking additive.

  Furthermore, when the cationic polymer and the anionic polymer are separately dissolved and added to the paper material, the cationic polymer and the anionic polymer can be separately added to the paper pulp slurry to be treated. . In this case, the cationic polymer and the anionic polymer may be added simultaneously, or may be added with a time difference.

  When the papermaking additive of the present invention is added to the stock, or when the cationic polymer and the anionic polymer are added separately to the stock, the amount added to the stock is not particularly limited. For example, the total amount of the cationic polymer and the anionic polymer as active ingredients is preferably 50 to 300 ppm, more preferably 100 to 250 ppm, based on the total solid content of the paper.

  In the paper manufacturing method of the present invention, in addition to the papermaking additive of the present invention, additives conventionally used in the papermaking industry can be used, such as paper strength enhancers, sizing agents, and dyes. Additives may be added to the stock. Further, calcium carbonate, clay, talc, silica, and the like may be added as fillers for paper stock such as pulp slurry.

As described in detail above, the papermaking additive of the present invention can reduce drainage without causing problems of lowering the formation of paper products and increasing costs even if the amount added to the paper stock is relatively small. Can be improved. Therefore, the papermaking additive of the present invention is suitably used as a freeness improver.
Further, since the drainage is improved by adding the paper additive of the present invention to the stock, the yield is also improved, and the paper additive of the present invention is also suitable as a yield / drainage improver. Used for.
According to the paper manufacturing method of the present invention using such a papermaking additive of the present invention, it is possible to manufacture high-quality paper even when raw paper-based raw materials are used.

The reason why the paper additive of the present invention exhibits excellent drainage is not clear, but is considered as follows.
The additive for papermaking of the present invention includes a cation that causes precipitation by using both polymers in combination in the range of 0.0001 to 0.01 part by weight of an anionic polymer with respect to 100 parts by weight of the cationic polymer. It is thought that it is not a strong electrostatic adsorption with an anion but takes a moderate cross-linked structure. As a result, it is considered that the effect of capturing inorganic fine particles such as pulp fibers and calcium carbonate is improved, and it is considered that excellent drainage is exhibited.

  Since the cationic polymer in the paper additive of the present invention is excellent in agglomeration effect, for example, in order to reuse the pulp fiber contained in white water, the paper fiber additive of the present invention is added to white water to obtain pulp fiber. Can also be used for the purpose of agglomerating and recovering it. At this time, the pulp fibers can be aggregated by adding about 1 to 2 ppm of papermaking additive with respect to the mass of white water.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative examples.

Table 1 shows anionic polymers used in the production examples described later.
As this anionic polymer, four types having different weight average molecular weights Mw were used. The composition and intrinsic viscosity of the anionic polymer used are shown in Table 1. Hereinafter, the used anionic polymer is shown using a sample number (No.) shown in Table 1. In Table 1, “NaA” represents sodium acrylate, and “AAm” represents acrylamide.

  In the description of Table 1, the anionic polymer “A-1” is a product name “AQUALIC DL40S” manufactured by Nippon Shokubai Co., Ltd., and the anionic polymer “A-2” is a product name manufactured by Sanyo Chemical Industries, Ltd. “Scalon L-410” was used, and the anionic polymer “A-4” used was a trade name “Cliff Rock PA331” manufactured by Kurita Kogyo Co., Ltd. The anionic polymer “A-3” was obtained by polymerizing monomer components and was synthesized as follows.

<Example of production of anionic polymer A-3>
3.6 g of acrylic acid was weighed into about 50 ml of pure water, and then 2.5 ml of 2N-NaOH aqueous solution was added to confirm that the pH became neutral. Next, 1.14 g of ammonium persulfate was added and the whole was made up to 100 ml. The aqueous solution was placed in a 300 ml separable flask equipped with a condenser, a nitrogen inlet tube, and a thermometer. Polymerization was carried out for 12 hours by heating.
A portion of the obtained polymerization solution was taken and weighed, and then the anionic polymer was precipitated with methanol, purified by decantation several times, and then dried under vacuum for 48 hours. The yield calculated from the weight of the obtained solid polymer was 102.6% as sodium polyacrylate.
The intrinsic viscosity of the obtained anionic polymer A-3 in a 1N NaCl aqueous solution at 25 ° C. was 0.103 dl / g.

<Weight average molecular weight of anionic polymer>
The weight average molecular weights of the anionic polymers A-1, A-2 and A-4 are based on the nominal values of each manufacturer. For the anionic polymer A-3, the weight average molecular weight is calculated from the intrinsic viscosity of A-3 according to the following viscosity formula (Source: KJ McCarthy, CW Burkhardt, Journal of Applied Polymer Science, 33, 1699-1714 (1987)). Mw was calculated.
[Η] = 5.41 × 10 ⁻⁶ Mw ^0.981

<Production Example 1>
Separately, 0.27 mass% anionic polymer A-1 aqueous solution with a pure polymer content is prepared.
Next, 10.9 g of an 80% by weight aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as “DAA”, molecular weight 193.5), powdered acrylamide (hereinafter abbreviated as “AAm”, molecular weight 71) 18.5 g, N , N′-methylenebisacrylamide (hereinafter abbreviated as “MBA”, molecular weight 140) 2.5 ml of 0.009 mass% aqueous solution and 1 ml of A-1 aqueous solution were mixed, and the whole was made up to 100 ml. The aqueous solution was placed in a 300 ml separable flask equipped with a cooling tube, a nitrogen introduction tube, and a thermometer, and after nitrogen bubbling, 1 ml of an aqueous solution of potassium persulfate (hereinafter abbreviated as “KPS”) prepared to 1.36% by mass. The mixture was added and heated to 40 ° C. for polymerization for 12 hours.
A part of the obtained polymer gel was precipitated with acetone, and the solid concentration determined by vacuum drying the precipitate was 27.5% by mass, and the polymerization rate was 101.1%. The intrinsic viscosity of this polymer mixture was 11.8 dl / g. The sample name of this polymer mixture is “ACA1”.
The composition ratio of the cationic polymer is DAA / AAm / MBA = 15/85/5 × 10 ⁻⁴ (mol%), and the ratio of the anionic polymer A-1 to the cationic polymer is 0.001% by mass. (A-1 is 0.001 part by mass with respect to 100 parts by mass of the cationic polymer).

<Production Example 2>
Synthesis was carried out under the same conditions as in Production Example 1 except that the anionic polymer A-1 in Production Example 1 was changed to Anionic Polymer A-2 to obtain a polymer mixture. The polymerization rate was 100.2%, and the intrinsic viscosity was 12.4 dl / g. The ratio of the anionic polymer A-2 to the cationic polymer is 0.001% by mass (A-2 is 0.001 part by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA2”.

<Production Example 3>
Synthesis was carried out under the same conditions as in Production Example 1 except that MBA was not used to obtain a polymer mixture. The polymerization rate was 99.8% and the intrinsic viscosity was 11.5 dl / g. The ratio of the anionic polymer A-1 to the cationic polymer is 0.001% by mass (A-1 is 0.001 part by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA3”.

<Production Example 4>
Synthesis was carried out under the same conditions as in Production Example 1 except that 1 ml of the anionic polymer A-1 in Production Example 1 was changed to 8 ml to obtain a polymer mixture. The polymerization rate was 100.4%, and the intrinsic viscosity was 12.1 dl / g. The ratio of the anionic polymer A-1 to the cationic polymer is 0.008% by mass (A-1 is 0.008 parts by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA4”.

<Production Example 5>
Production Example 1 except that 1 ml of 0.27% by mass of anionic polymer A-1 aqueous solution with a pure polymer content in Production Example 1 was changed to 2 ml of 0.27% by mass of anionic polymer A-2 aqueous solution with a pure polymer content Synthesis was carried out under the same conditions as in to obtain a polymer mixture. The polymerization rate was 99.9% and the intrinsic viscosity was 11.7 dl / g. The ratio of the anionic polymer A-2 to the cationic polymer is 0.0002% by mass (A-1 is 0.0002 parts by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA5”.

<Production Example 6>
Synthesis was carried out under the same conditions as in Production Example 1 except that 1 ml of the anionic polymer A-1 in Production Example 1 was changed to 20 ml to obtain a polymer mixture. The polymerization rate was 100.8%, and the intrinsic viscosity was 2.8 dl / g. In addition, the precipitate considered to be a polyion complex generate | occur | produced at the time of intrinsic viscosity measurement, and it became a solution with low viscosity. The ratio of the anionic polymer A-1 to the cationic polymer is 0.02% by mass (A1 is 0.02 parts by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA6”.

<Production Example 7>
The polymer mixture was synthesized under the same conditions as in Production Example 1 except that the anionic polymer A-1 in Production Example 1 was changed to Anionic Polymer A-2 and 0.08 ml of this A-2 aqueous solution was mixed with a micropipette. Got. The polymerization rate was 108.1%, and the intrinsic viscosity was 12.6 dl / g. The ratio of the anionic polymer A-2 to the cationic polymer is 0.00008% by mass (A-2 is 0.00008 parts by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer is “ACA7”.

<Production Example 8>
Synthesis was performed under the same conditions as in Production Example 1 except that 1 ml of the KPS aqueous solution added in Production Example 1 was changed to 10 ml to obtain a polymer mixture. The polymerization rate was 100.1%, and the intrinsic viscosity was 6.4 dl / g. The sample name of this polymer mixture is “ACA8”.

<Production Example 9>
Synthesis was carried out under the same conditions as in Production Example 1 except that the anionic polymer A-1 in Production Example 1 was changed to Anionic Polymer A-3 to obtain a polymer mixture. The polymerization rate was 100.2% and the intrinsic viscosity was 11.1 dl / g. The ratio of the anionic polymer A-3 to the cationic polymer is 0.001% by mass (A-3 is 0.001 part by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA9”.

<Production Example 10>
Synthesis was carried out under the same conditions as in Production Example 1 except that the anionic polymer A-1 in Production Example 1 was changed to Anionic Polymer A-4 to obtain a polymer mixture. The polymerization rate was 99.7% and the intrinsic viscosity was 11.9 dl / g. The ratio of the anionic polymer A-4 to the cationic polymer is 0.005% by mass (A-4 is 0.005 parts by mass with respect to 100 parts by mass of the cationic polymer). The sample name of this polymer mixture is “ACA10”.

<Production Example 11>
Synthesis was carried out under the same conditions as in Production Example 1 except that the anionic polymer was not used, and a cationic polymer was obtained. The polymerization rate was 107.1% and the intrinsic viscosity was 12.5 dl / g. The sample name of this cationic polymer is “AC1”.

<Production Example 12>
A cationic polymer was obtained by synthesis under the same conditions as in Production Example 1, except that the anionic polymer and MBA were not used. The polymerization rate was 100.7%, and the intrinsic viscosity was 7.2 dl / g. The sample name of this cationic polymer is “AC2”.

<Production Example 13>
Synthesis was carried out under the same conditions as in Production Example 1, except that the anionic polymer A-1 in Production Example 1 was not used, and the addition amount of the 1.36 mass% KPS aqueous solution in Production Example 1 was changed to 10 ml. A cationic polymer was obtained. The polymerization rate was 101.1%, and the intrinsic viscosity was 7.2 dl / g. The sample name of this cationic polymer is “AC3”.

  Table 2 shows a sample list of each of the production examples described above.

Next, the following drainage tests were conducted in Examples and Comparative Examples. In addition, the papermaking additive used in each Example and Comparative Example will be described later.
<Drainage test>
After adding the newspaper waste paper beaten to 450 ml of Canadian Standard Freeness (CSF) so that the dry mass becomes 0.6% by mass, light calcium carbonate (made by Brilliant 1500 Shiraishi Kogyo Co., Ltd.) is completely dried. A sample (pulp slurry) was added so as to be 40% by mass with respect to the material.
Take 180 ml of pulp slurry in a polybeaker with a capacity of 300 ml, add a 0.1 mass% aqueous solution of “additive” used in each Example and Comparative Example described later, and use a stirrer equipped with turbine blades at 250 rpm. For 20 seconds. Next, a metal cylinder having an inner diameter of 50 mm is placed on a Nutsche fune laid with a nylon filter cloth, and the aggregated pulp slurry is poured into the cylinder, and the amount of filtrate after 10 seconds is measured using a graduated cylinder. Further, the wet paper remaining on the filter cloth is taken on a polyester filter cloth and pressed for 60 seconds under a pressure of 3.0 kg / cm ² , and the moisture content of the wet paper after pressing is measured.

<Examples 1-5>
In Example 1, the polymer mixture “ACA1”, in Example 2, the polymer mixture “ACA2”, in Example 3, the polymer mixture “ACA3”, in Example 4, the polymer mixture “ACA4”, In No. 5, the drainage test of the pulp slurry was conducted using the polymer mixture “ACA5” as an additive.

<Examples 6 to 8>
In Example 6, a polymer obtained by blending the cationic polymer AC1 and 0.001 part by mass of anionic polymer A-1 with respect to 100 parts by mass of AC1 (0.001% by mass of A-1 with respect to AC1). The pulp slurry was tested for drainage using the mixture as an additive.
In Example 7, a polymer obtained by blending the cationic polymer AC1 with 0.008 parts by mass of the anionic polymer A-1 with respect to 100 parts by mass of the AC1 (0.001% by mass of A-1 with respect to AC2). The pulp slurry was tested for drainage using the mixture as an additive.
In Example 8, the polymer obtained by blending the cationic polymer AC2 with 0.0002 parts by mass of the anionic polymer A-2 with respect to 100 parts by mass of the AC2 (0.002% by mass of A-2 with respect to AC2). The pulp slurry was tested for drainage using the mixture as an additive.

<Comparative Examples 1-5>
In Comparative Example 1, the polymer mixture “ACA6”, in Comparative Example 2 the polymer mixture “ACA7”, in Comparative Example 3 the polymer mixture “ACA8”, in Comparative Example 4 the polymer mixture “ACA9”, and in Comparative Example 5 the polymer mixture Using “ACA10” as an additive, a drainage test of pulp slurry was conducted.

<Comparative Examples 6 and 7>
In Comparative Example 6, a cationic polymer “AC1” was used as an additive, and in Comparative Example 7, a cationic polymer “AC2” was used as an additive, and a drainage test of pulp slurry was performed.

<Comparative Examples 8-12>
In Comparative Example 8, the cationic polymer “AC3” and 0.005 parts by mass of the anionic polymer “A-1” with respect to 100 parts by mass of the AC3 (0.001% by mass of A-1 with respect to AC3). ) A drainage test of the pulp slurry was conducted using the blended polymer mixture as an additive.
In Comparative Example 9, the cationic polymer “AC1” and 0.001 part by mass of the anionic polymer “A-3” with respect to 100 parts by mass of this AC1 (0.001% by mass of A-3 with respect to AC1) ) A drainage test of the pulp slurry was conducted using the blended polymer mixture as an additive.
In Comparative Example 10, the cationic polymer “AC1” and 0.001 part by mass of the anionic polymer “A-4” with respect to 100 parts by mass of this AC1 (0.001% by mass of A-4 with respect to AC1) ) A drainage test of the pulp slurry was conducted using the blended polymer mixture as an additive.
In Comparative Example 11, the cationic polymer “AC1” and 0.02 parts by mass of the anionic polymer “A-1” with respect to 100 parts by mass of this AC1 (0.02% by mass of A-1 with respect to AC1). ) A drainage test of the pulp slurry was conducted using the blended polymer mixture as an additive.
In Comparative Example 12, the cationic polymer “AC1” and 0.00008 parts by mass of the anionic polymer “A-2” with respect to 100 parts by mass of this AC1 (0.00008% by mass of A-2 with respect to AC1). ) A drainage test of the pulp slurry was conducted using the blended polymer mixture as an additive.

  Table 3 shows a list of test conditions for each of the above examples and comparative examples, and Table 4 shows the test results.

  In Examples 1 to 8, it was confirmed that the amount of filtrate after 10 seconds was larger than that of Comparative Examples 1 to 12, and the moisture content after pressing was low. As a result, it was confirmed that the paper additive of the present invention can improve the drainage with a relatively small addition amount, and without causing the problem of lowering the formation of the product and increasing the cost.

Claims (4)

1N NaCl aqueous solution at 30 ° C. obtained by polymerizing a cationic vinyl monomer represented by the following general formula (I) and a monomer component containing a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer A cationic polymer having an intrinsic viscosity of 8 dl / g or more,
An anionic polymer having a weight average molecular weight of 20000 or less,
An additive for papermaking, which is contained in an amount of 0.0001 to 0.01 part by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer.

In a solution of an anionic polymer having a weight average molecular weight of 20000 or less,
A polymer mixture obtained by polymerizing a monomer component including a cationic vinyl monomer represented by the following general formula (I) and a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer; ,
The ratio of the cationic polymer to the anionic polymer is 0.0001 to 0.01 parts by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer, and in a 1N NaCl aqueous solution at 30 ° C. A papermaking additive having an intrinsic viscosity of 8 dl / g or more.

In a solution of an anionic polymer having a weight average molecular weight of 20000 or less,
In synthesizing a cationic polymer by polymerizing a monomer component containing a cationic vinyl monomer represented by the following general formula (I) and a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer,
The ratio of the cationic polymer to the anionic polymer is 0.0001 to 0.01 parts by mass of the anionic polymer with respect to 100 parts by mass of the cationic polymer, and in a 1N NaCl aqueous solution at 30 ° C. A method for producing an additive for papermaking, wherein the cationic polymer is synthesized so that the intrinsic viscosity at 8 is at least 8 dl / g.

1N NaCl aqueous solution at 30 ° C. obtained by polymerizing a cationic vinyl monomer represented by the following general formula (I) and a monomer component containing a nonionic vinyl monomer copolymerizable with the cationic vinyl monomer A cationic polymer having an intrinsic viscosity of 8 dl / g or more,
An anionic polymer having a weight average molecular weight of 20000 or less,
A method for producing paper, comprising adding 0.0001 to 0.01 part by mass of the anionic polymer to 100 parts by mass of the cationic polymer.