JP4722535B2 - Paper-making paper quality improver - Google Patents

Description

  The present invention relates to a paper-making paper quality improver that improves optical properties such as bulk (weight reduction), whiteness, and opacity of a sheet obtained by papermaking a pulp raw material.

  From the viewpoint of protecting the global environment, it is required to reduce the amount of pulp used. As a result, weight reduction of paper and increased blending of waste paper pulp are required. However, the paper obtained simply by reducing the amount of pulp in the paper is inferior in quality due to a decrease in opacity due to the thin paper. Further, in the light weight reduction that reduces the amount of pulp in paper, the paper that requires a rigidity proportional to the cube of the thickness, such as paperboard, is not desirable because the rigidity decreases. On the other hand, when the blending ratio of the used paper pulp is increased, the paper thickness is decreased and the opacity is decreased due to a decrease in whiteness due to residual ink in the used paper pulp or a decrease in the pulp itself in the recycling process. Accordingly, when the amount of pulp in the paper is reduced and the ratio of the used paper pulp is increased, the opacity and whiteness of the resulting paper are further reduced. Further, when the whiteness of the waste paper pulp that causes a decrease in whiteness is increased by deinking or bleaching, the opacity of the obtained paper is further decreased, which is not preferable.

  Various bulk improvement methods have been attempted for the purpose of preventing thickness reduction due to weight reduction. For example, the production method for reducing the press pressure has a problem that the smoothness is lowered and the printability is inferior. In addition, methods such as using crosslinked pulp, blending with synthetic fibers, filling fillers such as inorganic substances between pulp fibers, and providing voids can also be mentioned. Smoothness may be impaired.

  On the other hand, in order to improve opacity and whiteness, a method of adding a large amount (for example, 5 to 20% by weight) of an inorganic filler such as calcium carbonate, kaolin, or white carbon is practiced in the art. However, when a large amount of inorganic filler is simply added, the weight of the paper increases significantly. Even if the amount of pulp is reduced and an inorganic filler is added, the weight of the paper cannot be reduced. In particular, when an inorganic filler is added to waste paper pulp, a large amount is required, and the weight reduction of paper becomes increasingly difficult.

Patent Document 1 discloses a paper additive using a specific copolymer that can improve whiteness, opacity, and bulk of paper, and Patent Document 2 improves paper quality even in papermaking in a high shear state. A paper-making paper quality improver that combines a specific copolymer and a surfactant capable of obtaining an effect is disclosed.
Japanese Patent No. 3517200 (Claim 1) JP 2004-52216 A (Claim 1)

  The paper-making paper quality improver described in Patent Document 2 is excellent in paper quality improvement effect even in paper making in a high shear state. However, since a surfactant is used in combination with a specific copolymer, depending on the paper-making conditions, Problems such as foaming may occur.

  In this industry, a paper quality improver that can obtain higher bulk performance under high shear conditions where the paper making speed is high is desired. The high-speed papermaking is not a papermaking under static conditions in which the pulp is diluted with a large amount of water and filtered by its own weight, as in the TAPPI papermaking described in the above-mentioned prior art, but the wire is not like papermaking in an actual machine. This is a papermaking method under dynamic conditions in which a pulp slurry is continuously sprayed on a moving surface and a high shear force is applied.

  In the present invention, even in papermaking in a high shear state, by adding it before any papermaking step, the problem of foaming is reduced, and at least one of the whiteness improvement, opacity improvement, and bulk improvement effect of the paper is achieved. An object of the present invention is to provide an improved papermaking paper quality improver.

  The present invention relates to a paper-making paper quality improver containing a polymer having a structural unit containing a site having surface activity and a structural unit derived from one or more of an anionic monomer and a cationic monomer.

  According to the present invention, in papermaking in a high shear state, even when added in a small amount, at least one of weight improvement and whiteness improvement and opacity improvement required by weight reduction of paper and increased compounding of waste paper pulp can be achieved, In addition, a paper-making paper quality improver that can reduce the problem of foaming is provided.

  As described above, since the paper-making paper quality improver described in Patent Document 2 uses a surfactant in combination with a specific copolymer, problems such as foaming due to the surfactant may occur depending on the paper-making conditions. On the other hand, the paper-making paper quality improver of the present invention introduces a constitutional unit containing a site having surface active ability into the polymer, so that it does not cause foaming even in paper making in a high shear state without using a surfactant. An excellent paper quality improvement effect can be obtained while reducing problems.

  The paper-making paper quality improver of the present invention contains a polymer having a structural unit containing a site having surface activity and a structural unit derived from one or more of an anionic monomer and a cationic monomer. Examples of the basic skeleton (main chain) of the polymer include vinyl polymers, polyesters, polysaccharide derivatives, and the like. The content of the polymer in the papermaking paper quality improver is preferably 1 to 100% by weight, and more preferably 10 to 100% by weight. Furthermore, when the papermaking paper quality improver is an aqueous solution, the content of the polymer is preferably 5 to 70% by weight, more preferably 5 to 60% by weight, and particularly preferably 10 to 50% by weight.

  The anionic or cationic monomer as used in the present specification is not only a monomer having an anionic property or a cationic property, but a monomer that may be ionic by a change in pH. Moreover, the nonionic monomer as used in this specification is a monomer which does not become anionic or cationic by the change of pH.

  In the present invention, the structural unit including a site having surface activity is a unit in which a site having surface activity (hereinafter referred to as a surfactant unit) and the main chain of the polymer are bonded. This bonding form is not particularly limited, and may be a covalent bond or an ionic bond. A covalent bond is preferred in that the surfactant unit is less likely to be detached from the polymer. You may have 2 or more types of the structural unit which the surfactant unit couple | bonded in the polymer.

  The surfactant unit is a unit derived from a compound having surface active ability, and is introduced into the polymer as a side chain having surface active ability. The surfactant unit refers to those having a critical micelle concentration (hereinafter referred to as CMC) of a compound that is derived from 10,000 ppm or less.

  In the aqueous surfactant solution, when the surfactant concentration is increased, micelles are formed when a certain concentration is exceeded, and there is a concentration region in which properties (for example, surface tension, etc.) change greatly. The surfactant concentration at which aggregates (micelles) begin to form is called CMC. The CMC referred to in the present invention also means this. CMC uses the values described in “7.2 Basic Properties of Surfactants” in “Fourth Edition, 2001, Oil Chemistry Handbook-Lipids and Surfactants” (edited by the Japan Petrochemical Society, Maruzen Publishing). When there is no description, it measures by a vertical plate method (Wilhelmy method) at 25 degreeC using surfactant corresponding to surfactant unit.

  The CMC of the surfactant corresponding to the surfactant unit is preferably 0.001 to 10,000 ppm, more preferably 0.001 to 1000 ppm, and particularly preferably 0.01 to 100 ppm.

  The surfactant unit has a hydrophilic portion and a hydrophobic portion. The hydrophilic part is polyethylene oxide, acylglycerol, fatty acid alkylolamide, polyhydric alcohol type, amine oxide when nonionic, carboxylate, sulfate ester, sulfonate, ethoxysulfate when anionic. Salts, ethoxyacetic acid ester salts, phosphoric acid ester salts, in the case of cationic, primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, etc. are mentioned, and polyethylene oxide is particularly preferable. .

  The hydrophobic part is preferably one or more selected from the group consisting of an alkyl group having 4 to 40 carbon atoms, an alkenyl group having 4 to 40 carbon atoms, and an aryl group having 6 to 40 carbon atoms, linear or Any of the branched chains may be used. An alkyl group having 10 to 22 carbon atoms is particularly preferable.

In the present invention, the surfactant unit preferably has a structure represented by the general formula —X— (AO) _n —R. In this structure, X- (AO) _n corresponds to the hydrophilic part and R corresponds to the hydrophobic part. That is, the polymer of the present invention preferably has a structural unit derived from a monomer having a group represented by the general formula -X- (AO) _n -R.

In the above general formula, X is a linking group to the site of the compound corresponding to the main chain, and is preferably a divalent group derived from a compound having active hydrogen, such as —O—, —O—CO—, — S-, -PO ₄ -, include -NH-CO-. AO is an oxyalkylene group, and examples thereof include an oxyethylene group, an oxypropylene group, an oxybutylene group, and an oxystyrene group. n is an average added mole number, 2-20 are preferable, and 2-15 are especially preferable. (AO) _n may contain two or more oxyalkylene groups, and the addition form may be either block or random. In order to impart hydrophilicity to X- (AO) _n , it is preferable that at least 50 mol% of AO is an oxyethylene group.

In the above general formula, R is preferably one or more selected from the group consisting of an alkyl group having 4 to 40 carbon atoms, an alkenyl group having 4 to 40 carbon atoms, and an aryl group having 6 to 40 carbon atoms, An alkyl group having 10 to 40 carbon atoms is preferable, and an alkyl group having 10 to 22 carbon atoms is particularly preferable. Thus, the present invention relates to —X— (AO) _n —R wherein X is a divalent group derived from a compound having active hydrogen, AO is an oxyalkylene group, and n is the average number of moles added. 1 or more groups selected from the group consisting of an alkyl group having 4 to 40 carbon atoms, an alkenyl group having 4 to 40 carbon atoms, and an aryl group having 6 to 40 carbon atoms. It is. And a paper-making paper quality improver comprising a polymer having a structural unit derived from a monomer having a group represented by formula (II) and a structural unit derived from one or more of an anionic monomer and a cationic monomer. It is.

  The structure of the main chain of the constituent unit to which the surfactant unit is bonded is preferably a structure derived from an unsaturated monomer compound, and the surfactant unit is bonded by a covalent bond or an ionic bond. The covalent bond is formed by a group corresponding to X in the general formula of the surfactant unit described above, for example, an ether group, an ester group, a thioether group, a phosphoric acid group, an amide group, or the like. Examples of the main chain include structures derived from unsaturated alcohols such as allyl alcohol, unsaturated carboxylic acids such as (meth) acrylic acid, unsaturated thiols, and the like. An ionic bond is an anionic group or a cationic group, and is bonded at a portion having a charge of a compound corresponding to the main chain and a charge opposite to the main chain of the surfactant unit. Examples of the main chain include structures derived from anionic monomers and cationic monomers described below.

  The polymer according to the present invention has a structural unit derived from one or more of an anionic monomer and a cationic monomer in addition to the structural unit to which the surfactant unit is bonded. Of these, structural units derived from one or more cationic monomers are preferred. In addition, the compound which becomes the origin of the structural unit containing the site | part which has surface active ability is excluded from an anionic monomer and a cationic monomer.

  The anionic monomer is preferably an unsaturated monomer, for example, a monocarboxylic acid such as (meth) acrylic acid or crotonic acid; a dicarboxylic acid such as maleic acid, fumaric acid, itaconic acid or muconic acid or a half ester thereof; vinyl sulfone Examples thereof include sodium salts, potassium salts, ammonium salts and the like of organic sulfonic acids such as acid, styrene sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid. Among these, (meth) acrylic acid is particularly preferable. (Meth) acrylic acid has one or more meanings selected from acrylic acid and methacrylic acid.

  As the cationic monomer, an unsaturated monomer is preferable, and dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, allylamine, diallylamine, triallylamine; or These inorganic acids such as hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, salts of organic acids, or methyl halide (chloride, bromide, etc.), ethyl halide (chloride, bromide, etc.), benzyl halide (chloride, bromide, etc.), dialkyl (methyl) And vinyl monomers containing quaternary ammonium salts obtained by reaction with quaternizing agents such as sulfuric acid, dialkyl (methyl, ethyl, etc.) carbonic acid, epichlorohydrin and the like. Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, allylamine, diallylamine, triallylamine are copolymerized, and then hydrochloric acid, sulfuric acid, acetic acid, It can also be used by treating with a salt of an inorganic acid such as phosphoric acid or an organic acid. Among these, dimethylaminoethyl (meth) acrylate is particularly preferable. (Meth) acrylate has one or more meanings selected from acrylate and methacrylate. (Meth) acrylamide means at least one kind selected from acrylamide and methacrylamide.

  The paper-making paper quality improver of the present invention may contain a structural unit other than a structural unit having a surfactant unit and a structural unit derived from an anionic monomer and a cationic monomer, or derived from a nonionic monomer. And structural units derived from amphoteric monomers. From the viewpoint of improving paper quality, it is preferable to have a structural unit derived from a nonionic monomer in the papermaking paper quality improver. In addition, the compound which becomes the origin of the structural unit containing the site | part which has surface active ability is excluded from a nonionic monomer and an amphoteric monomer.

  The nonionic monomer may be saturated or unsaturated. In particular, an unsaturated monomer is preferable, for example, (meth) acrylic acid having 1 to 40 carbon atoms, preferably 2 to 24 alkyl ester, vinyl alcohol having 1 to 40 carbon atoms, preferably 2 to 24 alkyl ester, Alkyl modified (meth) acrylamide having 2 to 40 carbon atoms, preferably 3 to 24 carbon atoms, alkoxy modified (meth) acrylamide having 2 to 40 carbon atoms, preferably 3 to 24 carbon atoms, 1 to 40 carbon atoms of maleic acid Mono or dialkyl ester, C1-C40 mono or dialkyl ester of fumaric acid, styrene, vinyl toluene, α-methyl styrene, ethylene, propylene, butadiene, polyalkylene glycol (meth) acrylate, alkoxy polyalkylene glycol (meth) acrylate Polyalkylene glycol al Vinyl ether, alkoxy polyalkylene glycol alkenyl ether, and the like.

  Further, from the viewpoint of improving paper strength, a part of the structural unit derived from the crosslinkable monomer can be used. The crosslinkable monomer may be a nonionic unsaturated monomer, an anionic monomer, a cationic monomer, or a monomer not belonging to these. Since the degree of crosslinking greatly depends on the molar ratio, the ratio is preferably 0.001 to 5 mol%, more preferably 0.01 to 1 mol%, and more preferably 0.05 to 0.5 mol with respect to all constituent monomers. Mole% is particularly preferred. Examples of cross-linkable monomers include methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, hexamethylene bis (meth) acrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth). Bifunctional crosslinkable monomers such as acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, diallyl (meth) acrylamide, or 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanurate, tri And polyfunctional crosslinking monomers such as pentaerythritol acrylate, trimethylolpropane acrylate, triacryl formal, and diacryloylimide.

  The monomer composition ratio of the polymer according to the present invention is 1 to 99 mol% of a structural unit including a surfactant unit from the viewpoint of improving bulkiness, opacity, and whiteness, and is a total of an anionic monomer and a cationic monomer. It is preferable that it is 1-50 mol%. Moreover, it is preferable that structural units other than the structural unit containing a surfactant unit and the structural unit derived from an anionic monomer and a cationic monomer are 49-98 mol%. As for the structural unit containing a surfactant unit, 1-30 mol% is more preferable.

  In the polymer of the present invention, it is preferable that the compound that is a structural unit containing a surfactant unit is nonionic. Moreover, it is preferable to have a structural unit derived from ionic monomers, such as an anionic monomer and a cationic monomer. Moreover, it can also have the structural unit derived from the nonionic monomer which does not have surface active ability. Therefore, it is preferable to have a structural unit derived from a nonionic monomer having surface activity and a structural unit derived from an ionic monomer, and further, a structural unit derived from a nonionic monomer having no surface activity. It is preferable to have.

  The polymer of the present invention is preferably water-soluble. Water-soluble means that a 1% by weight aqueous solution of the polymer at 25 ° C. is transparent. Transparent means that the aqueous solution has a transmittance (%) measured by a cell having an optical path of 10 mm at a visible light of 660 nm. When the value is 100%, it means 90% or more.

In addition, the paper-making paper quality improver of the present invention is preferably one that provides one or more of the following paper quality improvement effects (i), (ii), and (iii).
(I) Standard bulk improvement is 0.02 g / cm ³ or more (ii) Standard opacity improvement is 0.5 points or more (iii) Standard whiteness improvement is 0.5 points or more

<Measurement method of standard bulk improvement>
(1) Hardwood bleached pulp derived from beech (hereinafter referred to as LBKP) is cut into 5 cm and 5 cm, disaggregated in a certain amount at 25 ± 3 ° C. with a beater, and 410 ± 20 ml at a Canadian standard freeness (JIS P 8121) To obtain an LBKP slurry having a pulp concentration of 0.4% by weight.

The pulp slurry was weighed so that the basis weight of the sheet after humidity control was 82 ± 2 g / m ^2, and then 3.0 parts by weight of a papermaking paper quality improver was added to 100 parts by weight of the pulp. Paper with an 80-mesh wire using an orientation paper machine for industrial use (manufactured by Kumagai Riki Kogyo Co., Ltd.) to obtain a wet sheet.

[Paper making conditions]
Paper making speed: 800 m / min Spray pressure: 0.1 MPa
Injection nozzle: Small injection nozzle Angle: 85 °
Spray nozzle distance: 40mm
Dehydration rate: 500 r / min Dehydration time: 30 seconds

  The obtained wet sheet was divided into three equal parts, each of which was produced by Advantech Toyo Co., Ltd. production filter paper No. Two 26 (270 mm 270 mm) and coach plates are stacked and coached. With two new filter papers each, the upper and lower sides of the sheet are sandwiched and pressed at a pressure of 340 ± 10 kPa for 5 minutes. After pressing, only the sheet is dried at 105 ± 3 ° C. for 2 minutes using a mirror dryer. The dried sheet is conditioned for 5 hours or more at 23 ° C. and 50% humidity. The conditioned sheet is cut into 150 mm and 150 mm.

(2) The weight of the cut sheet is measured, and the basis weight (g / m ² ) is obtained by the following calculation formula (3).
Basis weight (g / m ² ) = sheet weight / 0.0225 (3)

  Next, the thickness of the conditioned sheet is measured at five or more locations using a paper micrometer at a pressure of 53.9 ± 4.9 kPa, and the average value obtained is defined as the thickness (mm).

(3) The tension d (g / cm ³ ) is determined by the following formula (4) from the basis weight and thickness obtained above.
d = basis weight / thickness / 1000 (4)

In addition, a sheet is prepared in the same manner without adding a compound that becomes a paper-making paper quality improver, and the tenacity obtained in the same manner is defined as d ₀ .

(4) bulk density was determined by the d, from d _0, obtains the bulkiness improved degree the following equation (5).
Standard bulkiness improvement (g / cm ³ ) = d ₀ −d (5)

<Measurement method of standard whiteness improvement>
(1) Same as (1) in the standard bulk improvement measurement method.
(2) The humidity-adjusted sheet is measured for whiteness B by JIS P 8123 Hunter whiteness. Further, a sheet is prepared in the same manner without adding a paper-making paper quality improver, and the whiteness obtained in the same manner is B ₀ .
(3) In the above-obtained brightness B, and B _0, obtains the standard whiteness enhancer of the following equation (6).
Standard whiteness improvement (points) = B−B ₀ (6)

<Measurement method of standard opacity improvement>
(1) Same as (1) in the standard bulk improvement measurement method.
(2) The opacity P of the conditioned sheet is measured according to JIS P 8138A. Further, a sheet is prepared in the same manner without adding a papermaking paper quality improver, and the opacity obtained in the same manner is defined as P ₀ .
(3) opacity P obtained in the above, the P _0, obtains the standard opacity improvement of the following equation (7).
Standard opacity improvement (points) = P−P ₀ (7)

  The polymerization method of the polymer according to the present invention is not particularly limited, and for example, a known polymerization method such as solution polymerization or bulk polymerization using a polymerization initiator can be employed. The polymerization method can be carried out either batchwise or continuously. In this case, a known solvent can be used as the solvent is used without any particular limitation. Examples of such solvents include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-heptane; esters such as ethyl acetate. A ketone selected from the group consisting of water and a lower alcohol having 1 to 4 carbons from the solubility of the monomer mixture and the copolymer obtained. It is preferable to use the above.

  As a polymerization initiator, a well-known thing can be used and it does not specifically limit. Examples of such a polymerization initiator include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; azo compounds such as azobis-2 methylpropionamidine hydrochloride and azoisobutyronitrile; benzoyl Peroxides such as peroxide, lauroyl peroxide, cumene hydroperoxide; and the like, and one or more of these can be used. At this time, as a promoter, reducing agents such as sodium bisulfite, sodium sulfite, molle salt, sodium pyrobisulfite, formaldehyde sodium sulfoxylate, ascorbic acid; amine compounds such as ethylenediamine, sodium ethylenediaminetetraacetate, glycine; More than one species can be used in combination.

  Chain transfer agents can also be used as needed. As the chain transfer agent, known ones can be used and are not particularly limited. For example, mercaptoethanol, mercaptoglycerin, mercaptosuccinic acid, mercaptopropionic acid, mercaptopropionic acid 2-ethylhexyl ester, octanoic acid 2-mercaptoethyl ester, 1, 8-dimercapto-3,6-dioxaoctane, decane trithiol, dodecyl mercaptan, hexadecanthiol, decanethiol, carbon tetrachloride, carbon tetrabromide, 痾 -methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, Dipentene, 2-aminopropan-1-ol and the like can be mentioned, and one or more of these can be used.

  The polymerization temperature is appropriately determined depending on the polymerization method used, the solvent, the polymerization initiator, and the chain transfer agent, but is usually performed within a range of 0 to 150 ° C.

  A solvent may be extracted from the reaction product obtained after the polymerization by drying under reduced pressure or the like, and the polymer may be separated by an operation such as pulverization.

  The papermaking paper quality improver of the present invention is added in any of the papermaking processes, and may be added as it is, or may be diluted with water or the like as necessary.

  The papermaking paper quality improver of the present invention can be widely applied to pulp raw materials such as mechanical pulp such as thermomechanical pulp (TMP), virgin pulp such as chemical pulp such as LBKP, and used paper pulp. When waste paper pulp is blended, the blending amount is preferably 10% by weight or more, more preferably 30% by weight or more in the raw material pulp.

  The papermaking paper quality improver of the present invention is added at any point before the papermaking process (internal addition). It is added before the papermaking process where a thin liquid of pulp raw material is filtered to form a paper layer as it travels over the wire mesh, and is used as a pulper, refiner, etc., a disintegrator, a beating machine, a machine chest, a head box, and white water. Although it may be added to a tank such as a tank or piping connected to these facilities, a place where it can be uniformly blended with a pulp raw material, such as a refiner, a machine chest, or a head box, is desirable. It is preferable that the paper-making paper quality improver of the present invention is made into a paper as it is after being added to the pulp raw material and remains mostly in the pulp sheet. It is preferably used for papermaking in a high shear state from the viewpoint of exhibiting the effect of the papermaking paper quality improver of the present invention. Examples of the papermaking machine include an oriented papermaking machine.

  In the papermaking method using the papermaking paper quality improver of the present invention, the papermaking speed is preferably 200 m / min or more, more preferably 300 m / min or more, from the standpoint of significant effects in improving bulk, whiteness, and opacity. 500 m / min or more is particularly preferable.

  In addition, a sizing agent, a filler, a yield improver, a drainage improver, a paper strength improver, etc. may be added during papermaking. In particular, in order for the paper-making paper quality improver of the present invention to exhibit its function, it is important to fix to pulp, and therefore an agent that promotes fixing (hereinafter referred to as a fixing accelerator) may be added. preferable. Examples of the fixing accelerator include aluminum sulfate, a compound having an acrylamide group, and polyethyleneimine. The addition amount of the fixing accelerator is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the pulp raw material. In particular, when a copolymer having an anionic structural unit is used, a higher effect can be expected when a fixing accelerator is used in combination. The addition amount of the fixing accelerator in the papermaking paper quality improver of the present invention is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the polymer. Further, a fixing accelerator may be included in the papermaking paper quality improver.

  The paper-making paper quality improver of the present invention is preferably added so that the polymer is 0.01 to 10 parts by weight with respect to 100 parts by weight of the pulp raw material, but even when added in a small amount such as 0.1 to 5 parts by weight. At least one of optical properties such as bulkiness effect, whiteness or opacity is improved.

  The compound which becomes the papermaking paper quality improver of the present invention can be used as a papermaking bulk improver, a papermaking whiteness improver, and a papermaking opacity improver.

  The paper quality improver according to the present invention can improve one or more of bulk, whiteness, and opacity. The effect of improving the paper quality is preferably improved by two or more, more preferably all three.

  In addition, the pulp sheet obtained by using the paper-making paper quality improver of the present invention is one of the item classifications described in pages 455 to 460 of “Paper Pulp Technology Handbook” (published by Paper Pulp Technology Association, 1992). It is suitably used for paper such as newspaper web, printing / information paper, wrapping paper, or paperboard.

  According to the present invention, there is provided a paper-making paper quality improver that can achieve at least one of bulk improvement, whiteness improvement, opacity improvement, and the like that are desired by reducing the weight of paper and increasing the amount of waste paper pulp even when added in a small amount. . Moreover, according to the paper-making paper quality improver of the present invention, a pulp sheet having improved bulk, whiteness and opacity can be obtained.

(I) Polymer No. 1 Production Example In a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introduction tube, and a reflux condenser, 309.1 parts by weight of isopropyl alcohol, 429.5 parts by weight of water, and 49. 5 parts of acrylamide (AAm). 9 parts by weight, 6.4 parts by weight of 90% -dimethylaminoethyl methacrylate in diethyl sulfate quaternized (MOEDES) aqueous solution, methacrylate of ethylene oxide adduct (average 10 moles) of lauryl alcohol as a surface active monomer ( C12E10MA) [-X- (AO) _n -R (R = C12 alkyl group; X = O; AO = oxyethylene group; n = 10)] 12.9 parts by weight were charged and nitrogen substitution was performed. It was. Subsequently, the temperature was raised to 62 ° C. in a nitrogen atmosphere, and 114.9 parts by weight of AAm, 93.8 parts by weight of an aqueous MOEDES solution, 188.8 parts by weight of C12E10MA, 187.4 parts by weight of isopropyl alcohol, and 187.4 parts by weight of water were added. Two liquids of 120.2 parts by weight of the mixed liquid and 2% -2,2′-azobis (2-amidinopropane) dihydrochloride (V-50) aqueous solution are dropped simultaneously, and both liquids are dropped over 5 hours. Ended. Next, after aging for 3 hours at the same temperature, the mixture was cooled and polymer No. 1 having a solid content of 27.5% by weight and a viscosity of 129 mPa · s was obtained. An aqueous solution of 1 was obtained. The viscosity of the aqueous polymer solution was measured using a B-type viscometer under the conditions of a rotor rotation speed of 30 revolutions / minute and a temperature of 25 ° C. The type of rotor used is no. 2 rotors.

  Polymer No. The polymers Nos. 2 to 8 have the monomer compositions shown in Table 1 and the above-mentioned polymer Nos. 1 was produced according to the polymerization method of Production Example 1. All the polymers were water-soluble.

  Using these polymers, the following evaluation was performed under the papermaking conditions in a high shear state using an oriented paper machine. The results are shown in Table 1. Moreover, the case where a polymer was not added was evaluated as a blank.

[Pulp raw material]
The virgin pulp shown below was used as a pulp raw material.

<Virgin pulp>
Chemical pulp LBKP (hardwood bleached pulp) was used after being disaggregated and beaten with a beater at 25 ° C. to obtain 0.4% LBKP slurry. The Canadian standard freeness (JIS P 8121) of this product was 410 ml.

[Paper making method]
LBKP is weighed so that the pulp basis weight of the sheet after papermaking is 84 g / m ² . Next, 3.0 parts by weight of various paper-making paper quality improvers (polymers) shown in Table 1 are added to 100 parts by weight of the pulp, and thereafter, paper-making is performed under the same conditions as (1) in the standard bulk improvement measurement method. A sheet was obtained. The tension, whiteness, opacity and specific burst strength of the obtained sheet were measured by the following methods. The difference from each blank is shown in Table 1. Since the results correspond to the standard bulk improvement, standard opacity improvement, and standard whiteness improvement, they are shown as such in Table 1.

<Evaluation items and methods>
-Tightness The basis weight (g / m ² ) and thickness (mm) of the conditioned sheet were measured, and the tightness (g / cm ³ ) was determined by the following formula.
Tension = (basis weight) / (thickness) × 0.001
The smaller the tension is, the higher the bulk is, and the difference of 0.02 in the tension is fully recognized as a significant difference.

・ Whiteness
According to JIS P 8123 Hunter whiteness (measurement of whiteness B). A difference of 0.5 points in whiteness is fully recognized as a significant difference.

・ Opacity
According to JIS P 8138A method (measurement of opacity P). A difference of 0.5 points in opacity is well recognized as a significant difference.

The symbols in Table 1 have the following meanings.
・ AAm: Acrylamide ・ BMA: Butyl methacrylate ・ MOEDES: Diethyl sulfate quaternization of dimethylaminoethyl methacrylate ・ C12E10MA: Ethylene oxide of lauryl alcohol (average 10 mol) Adduct methacrylate (ethylene oxide of lauryl alcohol (average 10 mol)) Additive CMC: 100ppm)
・ C14E8MA: methacrylate of ethylene oxide (average 8 mol) adduct of myristyl alcohol (CMC of ethylene oxide (average 8 mol) adduct of myristyl alcohol: 5 ppm)
-C16E8MA: methacrylate of palmityl alcohol ethylene oxide (average 8 mol) adduct (CMC of palmitic alcohol ethylene oxide (average 8 mol) adduct: 1.1 ppm)
・ C18E9MA: Methacrylate of stearyl alcohol ethylene oxide (average 9 mol) adduct (CMC of stearyl alcohol ethylene oxide (average 9 mol) adduct: 0.13 ppm)

  Moreover, in Table 1, the addition amount is a part by weight of polymer solid content with respect to 100 parts by weight of pulp.

<Test example>
Polymer No. 1 (product of the present invention) and polymer no. Using 8 (comparative product), the foaming property was evaluated by the test method using a circulating waterfall drop as follows. A test paper was prepared by adding 1.0 part by weight of an effective amount of a papermaking paper quality improver per 100 parts by weight of pulp to 500 g of 0.5% by weight pulp slurry. This was placed in a 1000 ml graduated cylinder (diameter 6 cm, height 54 cm, liquid shape in a circle), and a waterfall was dropped from the nozzle with a diameter of 3 mm to the center of the liquid surface at room temperature for 3 minutes. The waterfall was dropped from a height of 30 cm from the liquid level by feeding the test solution near the bottom of the graduated cylinder at 1.3 L / min with a pump. The foaming property was evaluated by the sum of the liquid amount and the foam amount after 3 minutes. As a result, polymer no. When the scale at the upper end of the foam was read with 1, it was 525 ml. On the other hand, polymer no. 8 was 900 ml.

Claims (5)

General formula -X- (AO) _n -R [wherein X is a divalent group derived from a compound having active hydrogen, AO is an oxyalkylene group, n is the average number of moles added, and is a number from 2 to 20 , R is an alkyl group having 10 to 22 carbon atoms. ] A paper-making paper quality improver comprising a polymer having a structural unit derived from a monomer having a group represented by formula (I) and a structural unit derived from one or more cationic monomers. Polymer, further nonionic monomer paper quality improver for papermaking according to claim 1, further comprising a structural unit derived from a (excluding a monomer having a group represented by the general formula). The proportion of the structural unit of the polymer is 1 to 30 mol% of a structural unit derived from a monomer having a group represented by the general formula, 1 to 50 mol% of a structural unit derived from a cationic monomer, and a nonionic monomer The papermaking paper quality improver according to claim 2 , wherein the constituent unit derived from (excluding the monomer having a group represented by the general formula) is 49 to 98 mol%. Structure of the portion to be the constituent unit group represented by the general formula of the polymer is bonded is selected from the group consisting of acrylic acid, a structure derived from an unsaturated monomer compound selected from methacrylic acid, and allyl alcohol, of claim 1-3 Any one of the papermaking paper quality improvement agents of a statement. A method for producing a pulp sheet, wherein the paper-making paper quality improver according to any one of claims 1 to 4 is added before any paper-making step to make paper.