JP4381171B2 - Information recording paper - Google Patents

Description

  The present invention relates to an information recording paper that is bulky (low density), has good rigidity and friction coefficient, and has excellent recording suitability.

  The information recording paper is printed by an electrophotographic method, an ink jet recording method, a thermal transfer method, or the like.

  In the electrophotographic system, characters and images are stored on the surface of the photoconductor by corona discharge in the dark, and then a reverse polarity toner is selected for the latent image formed by irradiating a light image corresponding to the original. Then, after adhering toner is transferred to the paper surface as a recording medium, it is recorded and held on the paper surface through a heat pressure fixing process between a pressure roll and a heating roll.

  Since the temperature of the heating roll required for fixing the toner is usually 180 ° C., the water inside the paper is rapidly evaporated by heating. Paper shrinks and curls with this moisture change, but if the degree of curl increases, running troubles easily occur in copiers and printers, and the accumulation in the sorter deteriorates and at the same time in the subsequent process. There is also a problem with workability. In recent years, the paper travel route has become complicated due to downsizing of copying machines, front-loading paper feeding, or frequent use of double-sided copying, and the number of cases where slight curl becomes a trouble in traveling has increased. In addition, laser beam printers that perform printing in large quantities by electrophotography are remarkably widespread, and more than 1000 sheets are continuously printed at a high speed, so that paper with smaller curls than ever is required.

  In the ink jet recording system, fine droplets of ink are ejected from ink nozzles by individual mechanisms and are deposited on recording paper, whereby dots are formed and recorded and held on the paper surface. In the ink jet recording system, paper that quickly absorbs ink and does not cause a decrease in print density and dot spreading or bleeding is required.

  In recent years, many environmental products have been manufactured in which information paper is blended with waste paper pulp. In general, waste paper pulp is deteriorated in dimensional stability due to fibrillation of long fibers or increase in fine fibers in the deinking process. Therefore, when an information recording paper containing a large amount of waste paper pulp is printed by the electrophotographic method, curling after copying is large, and wrinkles after copying due to moisture absorption become prominent, which is a serious problem. Furthermore, the fine fiber of waste paper pulp suppresses the effect of the sizing agent and paper strength agent contained in the papermaking raw material. For this reason, when information recording paper containing a large amount of waste paper pulp is printed by the ink jet recording method, there arises a problem such as deterioration in print image quality such as feathering, which is spread in dots.

  As described above, important qualities required for information paper include paper runnability in information recording equipment, dimensional stability against environmental changes, and printability when printing with an ink jet recording method. Increasing the bulk of the paper is effective for improving the rigidity and dimensional stability necessary for paper running. Further, the bulkiness can be reduced while maintaining the thickness of the paper, and is also required from the viewpoint of environmental protection of forest resources and the like, cost and the like.

  As a conventional technique for increasing the bulk of paper, there is a method of using a bulky pulp composition obtained by reacting a mixture of pulp and hydrophobic fibers with a crosslinking agent (see Patent Document 1). In addition, there is a method for producing a bulky pulp sheet by mixing cellulose pulp, a specific form of polyester composite fiber, and a heat-fusible binder (see Patent Document 2). However, the use of cross-linked pulp, synthetic fibers, etc. has the problem of making paper impossible to recycle. Further, there is a technique for producing a bulky neutral paper by filling hollow spherical vaterite type calcium carbonate (see Patent Document 3), but there is a problem that it is a special filler. In addition, there is a method of producing a low-density bulky paper by making paper from pulp and heat-expandable particles (see Patent Document 4). The method using foamable particles has a problem that the paper strength is remarkably lowered. In addition, there is a method using bacterial cellulose and expandable particles (see Patent Document 5), but a special cellulose called bacterial cellulose must be used, which is not practical.

  In addition to these methods, there is a method using a bulking agent for paper. In the method using a surfactant, a paper bulking agent comprising a specific alcohol and / or a polyoxyalkylene adduct thereof, a nonionic surfactant, or an ester compound of a polyhydric alcohol and a fatty acid (see Patent Document 8) is disclosed. (See Patent Documents 6 to 8). As for ester compounds of polyhydric alcohol and fatty acid, a recording paper using this compound is shown (see Patent Document 9). Although this recording paper can be bulky, the paper has a low coefficient of friction and stiffness, and when used in a copying machine or a laser printer, double feeding or empty feeding occurs, and paper is used for paper ejection. There was a case where the problem of poor alignment occurred. Further, in the case of the ink jet recording method, there has been a case in which a problem such as inferior print image quality such as spreading of ink dots spreads occurs.

Japanese Patent Laid-Open No. 4-185792 JP-A-3-269199 Japanese Patent No. 1755152 JP-A-5-230798 JP-A-11-200222 WO98 / 03730 Publication JP-A-11-200263 JP-A-10-152814 Japanese Patent Laid-Open No. 12-313167

  In view of the circumstances as described above, the problems of the present invention are bulky (low density), good rigidity and friction coefficient, excellent running property and integration of copying machines, printers, etc., printing suitability of inkjet recording methods, etc. It is to provide an excellent information recording sheet.

    As a result of diligent research on the above problems, the present inventors have found that a synthetic cationic polymer having a 7 wt% aqueous solution viscosity at 50 ° C of 20 mPa · s or more and a nitrogen content of 1.0 wt% or less, and a vinyl monomer-derived An information recording paper obtained by making a paper material containing a paper material containing a paper emulsion containing a polymer emulsion containing a polymer particle having a glass transition point of 90 ° C. or less having a structural unit of Reached.

    According to the present invention, it is bulky (low density), good in rigidity and friction coefficient, excellent in runnability and integration in copying machines, printers, etc., and has less ink bleeding when printing with an ink jet recording method. An information recording sheet having excellent aptitude and the like can be obtained.

  The paper quality improver used in the present invention is a substance described in Japanese Patent Application No. 2002-252659, the viscosity of a 7% by weight aqueous solution at 50 ° C. is 20 mPa · s or more, and the nitrogen content is 1.0% by weight or less. An internal paper quality improver comprising a polymer emulsion containing a synthetic cationic polymer and polymer particles having a structural unit derived from a vinyl monomer and having a glass transition point of 90 ° C. or lower.

(Synthetic cationic polymer)
The synthetic cationic polymer preferably has a nitrogen content (N%: analyzed by Kjeldahl method) of 0.05% by weight or more, more preferably 0.07% by weight or more, particularly preferably 0.1% by weight or more, and the upper limit is 1.0% by weight. It is preferably 0.9% by weight or less, and more preferably 0.7% by weight or less.
A polymer having a cationic group is preferable so that the nitrogen content is in this range. For the introduction of the cationic group, a cationic monomer may be polymerized, or a cationic group may be introduced into the polymer by reaction or the like.
When the nitrogen content is in this range, the effect of improving the paper quality such as rigidity and bulk of the present invention is sufficiently obtained.

  As the cationic group, an ammonium group or an amino group may be neutralized with hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, maleic acid, fumaric acid, citric acid, tartaric acid, adipic acid, lactic acid or the like.

  When the molecular weight of the synthetic cationized polymer is expressed by replacing it with aqueous solution viscosity, in the measurement method described later (B-type viscometer, 60 rpm, 50 ° C.), the 7 wt% aqueous solution viscosity is 20 mPa · s or more, and 40 mPa S or more is preferred, 65 mPa · s or more is more preferred, and the upper limit is preferably 10,000 mPa · s or less, more preferably 8,000 mPa · s or less, and particularly preferably 5,000 mPa · s or less.

  As the synthetic cationic polymer, a cationic polymerized unit derived from a monomer having a polymerizable unsaturated group (for example, vinyl group, vinylene group, vinylidene group, allyl group, etc.), preferably general formulas (1) to ( And a cationic polymer having one or more cationic polymer units selected from the group consisting of (meth) acrylic acid type, styrene type, vinyl pyridine type, vinyl imidazoline type and diallylamine type polymer units represented by 5).

(Where
R ¹ : hydrogen atom or methyl group R ² , R ³ , R ⁴ : the same or different, hydrogen atom, alkyl group having 1 to 22 carbon atoms or substituted alkyl group Y: —O— or —NH—
Z: an alkylene group having 1 to 12 carbon atoms or a hydroxyalkylene group X-: an anion. ).

  Z is preferably an alkylene group or a hydroxyalkylene group having 2 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, and particularly preferably a hydroxypropylene group.

R ² , R ³ and R ⁴ are preferably an alkyl group having 1 to 12 carbon atoms, more preferably 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, an i-propyl group, and an n-propyl group. It is done.

  Specific examples of X- include halogen ions such as chlorine, iodine and bromine, and organic anions such as sulfuric acid, sulfonic acid, methyl sulfuric acid, phosphoric acid and nitric acid.

(Where
R ^5: a hydrogen atom or a methyl group R ^6: an alkylene group R ⁷ having 1 to 3 carbon atoms, R ^8, R ^9: the same or different, carbon atoms which may have a hydrogen atom or a substituent 1 ~ 22 alkyl groups.
X-: The same meaning as described above. )

R ⁶ is preferably a methylene group. R ⁷ , R ⁸ and R ⁹ are preferably alkyl groups having 1 to 12 carbon atoms, more preferably 1 to 3 carbon atoms, such as a methyl group, an ethyl group, an i-propyl group, and an n-propyl group. Is mentioned. Substituents include hydroxyl groups and halogen atoms. Specific examples of X- include those mentioned above. The styrene polymer unit preferably has a substituent at the para position.

(Where
R ¹⁰ : hydrogen atom or methyl group R ¹¹ : hydrogen atom or alkyl group having 1 to 22 carbon atoms X −: the same meaning as described above. )
R ¹¹ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, an i-propyl group, and an n-propyl group, and particularly preferably. It is a methyl group. Specific examples of X- include those mentioned above.

(Where
R ¹² : hydrogen atom or methyl group R ¹³ : hydrogen atom or alkyl group having 1 to 3 carbon atoms R ¹⁴ : hydrogen atom or alkyl group having 1 to 22 carbon atoms X −: the same meaning as described above. )

R ¹³ is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom. R ¹⁴ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably 1 to 3 carbon atoms, and examples thereof include a methyl group, an ethyl group, an i-propyl group, and an n-propyl group, and particularly preferably. It is a methyl group. Specific examples of X- include those mentioned above.

(Wherein R ¹⁵ and R ^{16 are the} same or different and each represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. X − represents the same meaning as described above).

R ¹⁵ and R ¹⁶ are preferably the same or different and include a hydrogen atom, a methyl group, an ethyl group, an i-propyl group, an n-propyl group, and the like. Specific examples of X- include those mentioned above.

  The synthetic cationic polymer is preferably a copolymer containing nonionic polymer units. The nonionic polymer unit is more preferably a hydrophilic nonionic polymer unit. Here, the hydrophilicity of the polymerized unit means that the monomer as a group from which the polymerized unit is obtained in the organic conceptual diagram-basics and applications (written by Yoshio Koda, Sankyo Publishing Co., Ltd., issued May 10, 1984). The ratio [I / O] between inorganic (I) and organic (O) means 0.60 or more, preferably 1.00 or more, more preferably 1.30 or more.

Nonionic polymerized units can be obtained by copolymerizing with nonionic monomers. Examples of such nonionic monomers include vinyl alcohols; hydroxyalkyl groups (having 1 to 8 carbon atoms) such as N-hydroxypropyl (meth) acrylamide, hydroxyethyl (meth) acrylate, and N-hydroxypropyl (meth) acrylamide. (Meth) acrylic acid ester or (meth) acrylamide having a polyhydric alcohol such as polyethylene glycol (meth) acrylate (degree of polymerization of ethylene glycol 1 to 30); (meth) acrylamide; N-methyl Alkyl (carbon number 1-8) such as (meth) acrylamide, Nn-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide (Meth) acrylamide; N, N-dimethyl (meth) acrylamide, N, N -Dialkyl (total carbon number 2 to 8) (meth) acrylamide; such as diethyl (meth) acrylamide; diacetone (meth) acrylamide; N-vinyl cyclic amide such as N-vinylpyrrolidone; methyl (meth) acrylate, ethyl (meth) (Meth) acrylic acid ester having alkyl (1-8 carbon atoms) group such as acrylate, n-butyl (meth) acrylate; (meth) acrylamide having cyclic amide group such as N- (meth) acryloylmorpholine, etc. Illustrated.
The synthetic cationic polymer preferably has a nonionic polymer unit so as to have the above-described nitrogen content.

  For the purpose of improving polymerization stability and mechanical stability, a cationic polymer may be used in combination with a nonionic polymer. The nonionic polymer is preferably a semi-synthetic water-soluble polymer such as methyl cellulose, hydroxyethyl cellulose, or soluble starch; or a synthetic water-soluble polymer such as polyvinyl alcohol obtained by polymerizing the aforementioned nonionic monomer. It is preferable to use 0-100 mass parts with respect to 100 mass parts of all vinyl monomers, and, as for the usage-amount of a nonionic polymer, it is more preferable to use 0-50 mass parts.

(Polymer particles)
The polymer particles have a Tg of 90 ° C. or lower, preferably 80 ° C. or lower. When the Tg of the polymer is 90 ° C. or less, the internally added paper quality improver contained in the paper efficiently melts in the paper manufacturing process, and the paper quality improving performance such as rigidity and bulk becomes good. The lower limit is not particularly limited, but is preferably −10 ° C. or higher.

  The polymer particles preferably have a structural unit derived from a vinyl monomer. The content of the vinyl monomer in the polymer particles is preferably 50 to 100 mol%, more preferably 80 to 100 mol%. As a vinyl monomer, a vinyl compound, a vinylene compound, a vinylidene compound, and a cyclic olefin are contained, What is described below is mentioned preferably.

(1) Methyl (meth) acrylate ((meth) acryl is acrylic, methacrylic or a mixture thereof; the same shall apply hereinafter), ethyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid alkyl ester having an alkyl group having preferably 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, such as butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate;
(2) Fatty acid vinyl ester comprising an ester of a linear or branched fatty acid having 1 to 18 carbon atoms, preferably 1 to 6 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl pivalate, and vinyl alcohol. ;
(3) (Meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, 2- (meth) acrylamide-2- Examples thereof include an anionic monomer having a polymerizable unsaturated group such as methylpropane sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, or a salt thereof. Polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid include acid anhydrides, partial esters and partial amides or mixtures thereof. Examples of the “salt” include alkali metal salts (sodium salt, potassium salt, lithium salt, etc.), alkaline earth metal salts (calcium salt, magnesium salt, barium salt, etc.), ammonium salts (quaternary ammonium salt, quaternary ammonium salt, etc. Quaternary alkyl ammonium salts, etc.). Of these, sodium salts are the cheapest and preferred.

  (4) (Meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) Polymerizable unsaturation such as acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, N-vinylpyrrolidone, N-vinylacetamide Nonionic hydrophilic group-containing monomer having a group.

  (5) Amino group having a polymerizable unsaturated group such as N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, etc. Specific examples of the monomer-containing monomer or its acid neutralized product or its quaternized product can be given. Preferred acids for obtaining an acid neutralized product include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, maleic acid, fumaric acid, citric acid, tartaric acid, adipic acid, lactic acid and the like. Examples of the alkylating agent include alkyl halides such as methyl chloride, ethyl chloride, methyl bromide and methyl iodide, and general alkylating agents such as dimethyl sulfate, diethyl sulfate and di-n-propyl sulfate.

  (6) Styrene.

  Of the above vinyl monomers, use of a fatty acid vinyl ester is most preferable for improving the rigidity of the paper. The polymer particles used in the present invention can be obtained by emulsion polymerization, suspension polymerization or dispersion polymerization.

(B) The polymer emulsion contains the above-described polymer particles in a solid content of preferably 10 to 60% by weight, more preferably 15 to 55% by weight from the viewpoint of easy handling. The average particle size of the polymer particles is preferably from 0.1 to 50 μm, more preferably from 0.2 to 30 μm, from the viewpoints of emulsion stability, pulp adsorption and the like.

  Furthermore, the aforementioned cationic polymer is preferably contained in the emulsion in an amount of 0.5 to 30% by weight, more preferably 2 to 25% by weight, from the viewpoint of adsorbing the polymer particles to the pulp.

  The cationic polymer is preferably 5 to 200 parts by weight, more preferably 5 to 150 parts by weight, and particularly preferably 7 to 120 parts by weight with respect to 100 parts by weight of the polymer particles. The weight of the polymer particles is the weight of all monomers constituting the polymer particles.

In the present invention, the emulsion preferably contains 40 to 90% by weight, more preferably 45 to 85% by weight of a dispersion medium. The dispersion medium is preferably water, but may contain a lower alcohol. Examples of the lower alcohol include methyl, ethyl, isopropyl alcohol having 1 to 3 carbon atoms.
Furthermore, in addition to preservatives and bactericides, fillers and the like may be contained as additives.

  In the present invention, the blending amount of the paper quality improver is preferably 0.1 to 20% by weight of the paper quality improver relative to the raw material pulp, more preferably 0.1% from the viewpoint of bulkiness, copying machine, and printer suitability. ~ 5% solids by weight. The place where the paper quality improver is added is added before the paper making process. Although it is not particularly limited as long as it is a place before the papermaking process, it is preferably before a mixing chest or a secondary fan pump, and preferably before adding a yield improver.

  The information recording paper of the present invention is obtained by papermaking a paper stock containing a paper quality improver and pulp. In addition to various wood virgin pulps such as LBKP, NBKP, LBSP, NBSP, TMP, CTMP, BCTMP, GP, RGP, various types of used paper pulp such as used newspaper, magazine used paper, high quality used paper, and kenaf And non-wood fibers such as bamboo can be used alone or in combination as required. When used paper pulp is contained, there is a tendency that paper dimensional stability, ink bleeding, etc. tend to be inferior. However, in the present invention, good paper is obtained even if the used paper pulp per pulp is 10% by weight or more, and further 30% by weight or more. It is done.

  The filler internally added to the information recording paper of the present invention is not particularly limited. For example, clay, calcined kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, titanium dioxide, Inorganic fillers such as zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin, and fine hollow particles These can be used alone or in appropriate combination of two or more. In the present invention, it is preferable to use rosetta-type calcium carbonate in order to improve bulkiness, copyability and the like. The amount of filler used is about 3 to 20% by weight of the pulp.

In the information recording paper of the present invention, an internal sizing agent such as a rosin sizing agent, a synthetic sizing agent, a petroleum resin sizing agent, or a neutral sizing agent can be used. In the present invention, in order to improve the effect of bulkiness and printability, it is preferable to use an alkyl ketene dimer (AKD) or alkenyl succinic anhydride (ASA) sizing agent, particularly using an ASA sizing agent. It is preferable to do. The amount of the internal sizing agent added is preferably 0.1 to 5% by weight, particularly preferably 0.2 to 2% by weight, based on the total pulp.
In the information recording paper of the present invention, various conventionally used nonionic and cationic retention agents, freeness improvers, paper strength improvers, conductive agents and other internal additives for papermaking are necessary. Are appropriately selected and used.

  Examples of the internal additive for papermaking include sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum compounds such as basic aluminum chloride and basic polyaluminum hydroxide, and water-degradable alumina sol. Examples thereof include water-soluble aluminum compounds, polyvalent metal compounds such as ferrous sulfate and ferric sulfate, and silica sol.

  Other starches for papermaking, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Various compounds such as particle dispersions and derivatives or modified products thereof can be used.

  Furthermore, internal additives for papermaking such as dyes, colorants, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.

The type of the paper machine is not particularly limited, and can be appropriately made with a long paper machine, a twin wire machine, a Yankee paper machine, or the like. The press line pressure is used within the normal operating range. Furthermore, a surface treatment agent may be applied for the purpose of improving the surface strength, size, water resistance, and the like. As the surface treatment agent, commonly used starch, oxidized starch, modified starch, water-soluble polymers such as carboxymethylcellulose, polyacrylamide, and polyvinyl alcohol, water resistance, paper strength enhancer, and the like can be used. For the application of the surface treatment agent, the type of size press is not limited, and a liquid roll transfer type size press such as a 2-roll size press, a gate roll size press, or a shim sizer can be appropriately used. The calendar is used at a linear pressure within the normal operating range, but from the viewpoint of bulkiness, a low linear pressure is preferable as long as the smoothness of the paper can be maintained, and a soft calendar is preferable. Information recording sheet of the present invention is preferably a basis weight of 30 to 200 g / ^{m 2,} more preferably from 30 to 100 g / m ^2.

  The information recording paper of the present invention is bulky (low density) and has good rigidity and friction coefficient, and can be used for electrophotographic transfer paper, foam paper, inkjet paper, thermal transfer paper, and the like.

  Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, “parts” is parts by weight and “%” is% by weight.

<Production example of paper quality improver (emulsion)>
-Paper quality improver 1 (Emulsion 1: EM-1)
In a 2 L flask equipped with a reflux condenser, dropping funnel, thermometer, nitrogen inlet, and stirrer, cationic polyvinyl alcohol [PVA C-118, N% = 0.3%, 7% aqueous solution viscosity 67 mPa · s (50 ° C, B (Type viscometer, rotor No. 1, 60 rpm), Kuraray Co., Ltd.] 70 g and ion-exchanged water 570 g were charged and heated to 90 ° C. to dissolve. After cooling, 30 g of Emulgen 150 (nonionic surfactant, 20% aqueous solution, manufactured by Kao Corporation) and 11.4 g of 4% tartaric acid (reagent, manufactured by Wako Pure Chemical Industries, Ltd.) were added (all after addition) After the pH of the system was 44.0), the mixture was stirred at 120 rpm, heated to 60 ° C. while blowing nitrogen, and held for 30 minutes. Next, 20 g of vinyl acetate (manufactured by Shin-Etsu Vinyl Acetate Co., Ltd.) and 0.2 g of initiator (V-50, azo initiator, Wako Pure Chemical Industries, Ltd.) dissolved in 10 g of ion-exchanged water are added, Hold for 15 minutes. Next, after heating to 75 ° C., 380 g of vinyl acetate and 0.8 g of initiator (V-50) dissolved in 160 g of ion-exchanged water were dropped from separate dropping funnels over 3 hours, and polymerization was performed. went. Next, the temperature was raised to 82 ° C., aged for 1 hour, cooled, and taken out. The glass transition point (Tg) of polymer particles having vinyl acetate as a structural unit was 32 ° C. A cationic emulsion 1 having a solid content concentration of 36.3% and an average particle size of 5.68 μm was obtained.

-Paper quality improver 2 (Emulsion 2: EM-2)
In accordance with the production method of emulsion 1, the cationic polyvinyl alcohol is changed to polyvinyl alcohol having a mercapto group at the end (PVA M-115, N% = 0%, polymerization degree 1500, manufactured by Kuraray Co., Ltd.), and vinyl acetate is used. The emulsion 2 was obtained by changing to styrene / hydroxypropyltrimethylammonium chloride methacrylate = 95/5 (weight ratio) (the amount of ion-exchanged water was appropriately changed). Emulsion 2 had a solid content concentration of 32% and an average particle size of 5.52 μm.

<Example of manufacturing information recording paper>
(Example 1)
LBKP (freezing degree CSF 400 ml) was used as a pulp content, and light calcium carbonate was added thereto so that the content was 10%. 1.0% by weight of paper quality improver 1, 1.0% by weight of sulfate band (50% by weight sulfate band product), 0.5% by weight of cationized starch, alkyl ketene dimer A stock was prepared by adding a system sizing agent to a solid content of 0.4% by weight. An information recording paper having a basis weight of 80 g / m ² was obtained at a paper making speed of 500 m / min using a twin wire paper machine.
Table 1 shows the paper quality results.

(Example 2)
An information recording paper was obtained in the same manner as in Example 1 except that the alkyl ketene dimer sizing agent was changed to an alkenyl succinic anhydride sizing agent.
Table 1 shows the paper quality results.

Example 3
An information recording paper was obtained in the same manner as in Example 1 except that LBKP (freeness CSF 400 ml) and waste newspaper pulp were used at a ratio of 7/3 as the pulp content.
Table 1 shows the paper quality results.

(Comparative Example 1)
An information recording sheet was obtained in the same manner as in Example 1 except that the paper quality improver 1 was changed to a paper quality improver KB115 (produced by Kao Corporation), which is an ester of a polyhydric alcohol and a saturated fatty acid.
Table 1 shows the paper quality results.

(Comparative Example 2)
An information recording paper was obtained in the same manner as in Example 1 except that the paper quality improver 1 was changed to a paper quality improver PT-205 (manufactured by Nippon PMC Co., Ltd.), which is a saturated fatty acid amide.
Table 1 shows the paper quality results.

(Comparative Example 3)
An information recording paper was obtained in the same manner as in Example 1 except that the paper quality improver 1 was changed to an unsaturated fatty acid amide based paper quality improver DZ2220 (manufactured by NOF Corporation).
Table 1 shows the paper quality results.

(Comparative Example 4)
An information recording paper was obtained in the same manner as in Example 1 except that the paper quality improver 1 was changed to the paper quality improver KB08W (produced by Kao Corporation), which is an alcohol alkylene oxide adduct.
Table 1 shows the paper quality results.

(Comparative Example 5)
An information recording paper was obtained in the same manner as in Example 1 except that no paper quality improver was added.
Table 1 shows the paper quality results.

(Comparative Example 6)
An information recording sheet was obtained in the same manner as in Example 1 except that the paper quality improver 1 was changed to the paper quality improver 2.
Table 1 shows the paper quality results.

    From Table 1 to Examples 1 to 3, the bulkiness (low density), the rigidity and the coefficient of friction are low and good, the running property and the accumulation property of a copying machine, a printer, etc. are excellent. It is possible to obtain an information recording paper that has less bleeding and excellent printability. Comparative Examples 1 and 2 are inferior in stiffness, static friction coefficient, and copy suitability. Comparative Examples 3 and 4 are inferior in rigidity, copyability and feathering. In Comparative Examples 5 and 6, the density is high and the density is not low.

<Evaluation method>
Density: Measured according to JIS P 8118.
-Stiffness: A value obtained by dividing the value measured by the Clark stiffness tester in accordance with JIS P 8143 by the cube of the paper thickness and multiplying by the fifth power of 10 was used as an index.
-Coefficient of static friction: measured in accordance with ISO 15359. The friction coefficient was measured in the MD direction by superposing the F and W surfaces.
-Copying suitability: Fuji Xerox copier (DocuPrint C3530) prints 200 A3 sheets continuously. Fixing wrinkles, double feeding, jam troubles, and irregular papers after printing are suppressed. , Double feed, jam trouble, or paper misalignment after printing could not be suppressed.
Feathering: Printing was performed with a Canon inkjet recording apparatus (BF F210), and visual evaluation was performed in a 5-step evaluation from 1 (poor) to 5 (excellent).

Claims (3)

Synthetic cationic polymer having a 7 wt% aqueous solution viscosity at 50 ° C of 20 mPa · s to 5,000 mPa · s and (A) a nitrogen content of 0.05 wt% to 1.0 wt% and (B) acetic acid Containing an internal additive paper quality improver comprising a polymer emulsion containing a polymer particle having a vinyl monomer as a constituent unit and having a glass transition point of -10 ° C or higher and 90 ° C or lower, and a pulp, and further an alkyl ketene dimer system An information recording paper obtained by making a paper stock containing 0.1 to 5% by weight of a sizing agent or an alkenyl succinic anhydride sizing agent .   2. The information recording paper according to claim 1, wherein the amount of the internal paper quality improver is 0.1 to 20% by weight of the internal paper quality improver relative to the pulp. The synthetic cationic polymer is a polymer having one or more cationic polymer units selected from the group consisting of (meth) acrylic acid-based, styrene-based, vinylpyridine-based, vinylimidazoline-based and diallylamine-based polymer units having a cationic group. information recording sheet according to claim 1 or 2, characterized in that.