JP3277841B2 - Rosin emulsion sizing agent for papermaking, sizing paper and sizing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the use of a specific copolymer as an emulsifying and dispersing agent for a rosin-based material.
Shows excellent size effect in papermaking system from weakly acidic to alkaline region, low foaming property, mechanical stability,
The present invention relates to a sizing agent having redispersibility and storage stability, a sizing paper obtained by using the sizing agent, which has excellent suitability for inkjet printing, and a sizing method thereof.

[0002]

2. Description of the Related Art In the paper industry, pH using a sulfuric acid band
In order to avoid various problems such as corrosion of a paper machine and deterioration during storage of paper in an acidic papermaking method of 6 or less, neutral papermaking or alkali papermaking using inexpensive calcium carbonate as a filler is widely used. Examples of the sizing agent include sizing agents in which alkyl ketene dimer or alkenyl succinic anhydride is dispersed in a dispersing medium such as water, but all of these are expensive and have a major problem of increasing the cost of paper production. In addition, there are problems such as poor workability such as easy generation of dirt on a press roll or the like in a papermaking system, and a low speed (rise) of developing a size effect. In addition, all of these have a problem that the sizing effect on high-yield pulp such as mechanical pulp is inferior to rosin-based sizing agents.

As a neutral papermaking sizing method using a rosin-based substance containing rosin and its esters instead of the so-called reactive sizing agent using such an alkyl ketene dimer or alkenyl succinic anhydride, Japanese Patent Publication No.
JP 79840 discloses that papermaking is carried out using a sizing agent consisting of an aqueous dispersion in which a trivalent or tetravalent alcohol and a rosin esterified product are dispersed. Also,
As a polymer emulsifier for emulsifying a rosin-based substance, a dispersant obtained by neutralizing a copolymer of a styrene monomer and a (meth) acrylic monomer or a (meth) acrylamide-based dispersant (Japanese Patent Application Laid-Open No. No. 169898, JP-A-5-98
No. 125693, Japanese Patent Publication No. Hei 7-24747, Japanese Unexamined Patent Publication No.
No. 3894, JP-A-8-337997, etc.) and the like, and a sizing agent is obtained by emulsifying a rosin-based substance in water using these.

[0004]

However, papermaking is carried out using a sizing agent comprising a trivalent or tetravalent alcohol and a rosin esterified product as an aqueous dispersion described in Japanese Patent Publication No. 3-79840. The sizing method to be used depends on papermaking conditions, especially pH, when using the sizing agent.
If the sizing agent is not properly controlled, the desired sizing degree cannot be obtained, and since the sizing performance is low, it is necessary to increase the sizing agent addition rate, which not only increases the cost of the sizing agent itself, but also increases the papermaking system There is a problem that foaming and dirt become serious. In addition, the sizing agent obtained by emulsifying a rosin-based material using a dispersant obtained by neutralizing the copolymer of the styrene-based monomer and the (meth) acrylic acid-based monomer or a (meth) acrylamide-based dispersant, In fact, there are some points that are not satisfactory in emulsifying property, size effect, low foaming property, mechanical stability, storage stability and the like. In particular, compared with other dispersants, the (meth) acrylamide-based dispersants described in the above publications have problems in foaming properties and emulsifying properties. further,
Recently, inkjet printing has been widely used in office equipment, taking advantage of the fact that many types of small-volume printing are possible, but this inkjet printing is a solution in which a dye or pigment is dissolved or dispersed in a solvent. Is printed from paper nozzles to print characters, figures, etc. on paper, so that the paper used for the printing is required to have an image quality obtained using monochrome ink or color ink as inkjet printability. Suitability, that is, appropriate print density, feathering, strikethrough, and no bleeding at the boundary of the color-coded printing portion are required. For this reason, ordinary paper cannot satisfy its inkjet printability, and so-called inkjet paper has been developed to satisfy these requirements, but it is expensive and is widely used as office equipment. In addition, PPC paper, which is a large number of copy papers sold for printing, is required to have printability by an ink jet method, and it is hoped that inexpensive paper that satisfies the suitability of both PPC paper and ink jet print paper will appear. It is rare.

A first object of the present invention is to obtain a predetermined sizing degree without strictly controlling the pH and without increasing the addition ratio. It is an object of the present invention to provide a sizing agent with less foaming and dirt, a sizing paper and a sizing method using the same. A second object of the present invention is to provide a sizing agent which satisfies emulsifiability, sizing effect, low foaming property, mechanical stability, storage stability and the like, a sizing paper using the same, and a sizing method. A third object of the present invention is to provide a sizing agent capable of obtaining paper satisfying the suitability of both PPC paper and ink jet printing paper, a sizing paper using the same, and a sizing method.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that at a specific ratio, at least one of acrylamide and methacrylamide, a hydrophobic monomer, and a polymerizable compound of a carboxylic acid group-containing monomer . And dispersing the rosin-based substance in an aqueous dispersion medium with a polymer-based emulsifying dispersant containing a copolymer having at least one water-soluble mercaptan and at least one water-insoluble mercaptan as a copolymer component. It has been found that the sizing agent containing the dispersed liquid has excellent sizing effect, suitability for ink-jet printing, and low foaming property, and can solve the above-mentioned problems together with other effects, and has accomplished the present invention. That is, the present invention relates to a rosin emulsion sizing agent for papermaking comprising (1) a (A) rosin-based substance and (B) an emulsifying dispersant in an aqueous dispersion medium, wherein the (B) emulsifying dispersant comprises at least the following (a) ) To (c )
A polymerizable compound and at least one mercaptan belonging to each of the following (e) and (f) in the copolymer component, and (a) 40 to 90 mol%, (b) 3 to 20
(A) to (c) consisting of 6 to 40 mol%
It contains an acrylamide copolymer obtained by polymerizing 0.2 to 3 mol% of component (e) and 0.2 to 3 mol% of component (f) based on 100 mol% of monomer (c). A rosin emulsion sizing agent for papermaking is provided. (A) at least one of acrylamide and methacrylamide (b) hydrophobic monomers (c) monomers containing a carboxylic acid group and / or a salt thereof (e) water-soluble mercaptans (f) hardly water-soluble mercaptans The present invention relates to (2), (A) a rosin-based substance and (B)
A rosin emulsion sizing agent for papermaking containing an emulsifying dispersant in an aqueous dispersion medium, wherein the (B) emulsifying dispersant is at least one of the following (a) to (d ):
One type of polymerizable compound and at least one type of mercaptan belonging to each of the following (e) and (f) in the copolymer component, and (a) 40 to 90 mol%, (b) 3 to 2
0 mol%, (c) 6 to 40 mol% and (d) 0.5 to 5
100 mol% of the monomers (a) to (d) consisting of mol%
On the other hand, a rosin emulsion sizing agent for papermaking containing an acrylamide copolymer obtained by polymerizing the component (e) in an amount of 0.2 to 3 mol% and the component (f) in an amount of 0.2 to 3 mol%, a) at least one of acrylamide and methacrylamide; (b) hydrophobic monomers; (c) monomers containing a carboxylic acid group and / or a salt thereof; and (d) monomers containing a sulfonic acid group and / or a salt thereof. e) Water-soluble mercaptans (f) Poorly water-soluble mercaptans (3) and (c) wherein the components are carboxylic acid group-containing monomers, and the carboxylic acid group-containing monomers are dibasic carboxylic acid monomers. (1) or (2) a rosin emulsion sizing agent for papermaking, (4), (e) the water-soluble mercaptan is a mercaptan having 2 or 3 carbon atoms, and mercaptoethanol Or cysteamine hydrochloride, mercaptopropionic acid, mercaptopropionate, thioglycolic acid, thioglycolate, thioacetic acid, thioacetate, and (f) poorly water-soluble The rosin emulsion sizing agent for papermaking according to any one of the above (1) to (3), wherein the mercaptan is at least one of mercaptans having 4 to 18 carbon atoms, (5), (A) the rosin-based substance is a rosin ester And at least one of at least one of the fortified rosin esters, or at least one of the at least one of the rosins and the fortified rosins, and at least one of the rosin esters and the fortified rosin esters. At least one mixture, and at least one of rosin esters and fortified rosin esters The rosin emulsion sizing agent for papermaking according to any one of the above (1) to (4), wherein at least one of the rosin-based substances is not less than 10% by weight of the rosin-based substance, (6), any one of the above (1) to (5) Sizing paper sized using the papermaking rosin emulsion sizing agent, (7), pH 5.0-9.
The present invention provides a sizing method for obtaining sized paper by having a step of adding the rosin emulsion sizing agent for papermaking according to any one of claims 1 to 5 to a pulp slurry of No. 0. In addition, the above-mentioned invention (1) is described as "a method for producing a rosin emulsion sizing agent for papermaking containing a rosin emulsion obtained by emulsifying and dispersing a rosin-based substance (B) in an aqueous dispersion medium with an emulsifying dispersant. Wherein the (B) emulsifying dispersant is at least one type of polymer belonging to each of the following (a) to (c ):
A compound having at least one mercaptan belonging to each of the following (e) and (f) in the copolymer component, and (a) 40 to 90 mol%, (b) 3 to 20 mol%, and (C) 0.2 to 100 mol% of the monomers (a) to (c) consisting of 6 to 40 mol%,
A method for producing a rosin emulsion sizing agent for papermaking, comprising an acrylamide-based copolymer obtained by polymerizing 3 mol% and component (f) at 0.2 to 3 mol%. "
Other inventions may conform to this.

Hereinafter, the present invention will be described in detail. In the present invention, “(A) rosin-based substance” includes rosins,
At least one of fortified rosins, rosin esters and at least one of the fortified rosin esters is included. The rosins include gum rosin, tall oil rosin, and wood rosin, and further include hydrogenated rosin, disproportionated rosin, polymerized rosin, aldehyde-modified rosin, and the like, each of which is a modified product thereof. It can be used as an arbitrary mixture of at least two kinds. The reinforced rosins are obtained by subjecting the rosins to an addition reaction of an acidic compound having a -C = CC-O group in an amount of 1 to 20% by weight, preferably 3 to 18% by weight. Representative examples of the acidic compound include an α, β-unsaturated carboxylic acid and an anhydride thereof. Specific examples thereof include fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, and citraconic acid. Acids, α, β-unsaturated dibasic carboxylic acids such as citraconic anhydride and anhydrides thereof, and α, β-unsaturated monobasic carboxylic acids such as acrylic acid and methacrylic acid. Although two kinds can be used in combination, the reinforcing method can be performed by a known method.

[0008] Rosin esters are reaction products obtained by the esterification reaction of the above-mentioned rosins with alcohols, phenols, epoxy compounds, etc., and include complete and / or partially esterified products and unreacted products. Rosins may be included. As the alcohol, a polyhydric alcohol having a valency of 3 or more (not less than 3) can be used, and examples thereof include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, and sorbitol. As the phenol, a polyhydric phenol having a valency of 2 or more (not less than 2) can be used, and examples thereof include hydroquinone, pyrogallol, and bisphenol A. The epoxy compound is a compound having an oxirane ring, and examples thereof include an epoxy resin such as a glycidyl ether type epoxy resin. These alcohols, phenols, epoxy compounds and the like can be used in combination with at least one kind of each kind or at least one kind of at least two kinds. The esterification reaction between rosins and alcohols, phenols, epoxy compounds and the like can be performed by a known method, for example, by performing a dehydration reaction while stirring both at 150 to 300 ° C. for 3 to 30 hours. . The proportions of rosins and alcohols during the reaction are as follows: rosins are based on carboxyl groups, alcohols and phenols are hydroxyl groups, and epoxy compounds are oxirane rings as divalent hydroxyl groups. , The molar ratio of hydroxyl groups to carboxyl groups (-OH
/ -COOH) is preferably in the range of 0.2 to 1.3. When the molar ratio is less than 0.2, the content of the rosin ester contained in the reaction product is reduced, and the sizing agent containing the emulsion emulsified with the component (B) is used as the component (A). In such a case, the size effect in a high pH range may be reduced, and when the molar ratio exceeds 1.3, a large amount of free hydroxyl groups remains in the rosin ester to be generated. The size effect of the sizing agent may be reduced.

The fortified rosin ester is obtained by subjecting a rosin ester to an addition reaction with an α, β-unsaturated carboxylic acid and / or an anhydride thereof in the same manner as the above-mentioned fortified rosin. Before the esterification reaction, at the same time as the esterification reaction, or after the esterification reaction, any of these steps may be used in combination. When this is used as the component (A) and a sizing agent containing an emulsion emulsified with the component (B) is used, α, β-
It is preferable to carry out an addition reaction of an unsaturated carboxylic acid or the like.

The above-mentioned rosin esters and fortified rosin esters are usually completely esterified products in which all of the hydroxyl groups such as alcohols are esterified with carboxyl groups such as rosins, and those in which a part of the hydroxyl groups is esterified. It is a mixture with an esterified product and an unreacted rosin, but in the present invention, the mixture may be used as it is within the range of the charging ratio at the time of the esterification reaction, and the rosin and / or the reinforced resin may be used. It may be used as a dispersion phase of an aqueous dispersion by mixing with rosins. At this time, the ratio of the rosin ester and / or the fortified rosin ester in all the rosin-based substances is preferably 10 to 100% by weight.
In the sizing agent of the present invention, when this is less than 10% by weight, when the sizing agent contains the emulsion emulsified with the component (A) using the component (A),
The size effect in a neutral or alkaline region may be reduced. When the rosin and / or the fortified rosin and the mixture of the rosin ester and / or the fortified rosin ester are used as the sizing agent of the present invention as the rosin-based substance,
When this sizing agent is used in a papermaking system having a high pH, that is, in a neutral or alkaline region, it is more preferable in view of the above-mentioned sizing effect and low foamability.

In the present invention, the “(B) emulsifying dispersant” includes the above (a) to (c), (e) and (f), or (a) to (d), (e) and (f) )), Which contains an acrylamide-based copolymer having at least one kind of each component in the copolymer component. The acrylamide copolymer means a copolymer having at least one of acrylamide and methacrylamide as a copolymer component. “(A) at least one of acrylamide and methacrylamide” means that each of acrylamide and methacrylamide is used alone or in combination.
The ratio of the component (a) to the whole of the monomers (a) to (c) or (a) to (d) is 40 to 90 mol%, preferably 50 to 70 mol%. If the amount is less than 40 mol%, even if the rosin-based substance is emulsified in an aqueous medium using an emulsifying dispersant containing the above-mentioned copolymer, the dispersion stability and emulsifying property will be deteriorated. , The emulsifiability becomes worse.

Further, “(b) hydrophobic monomers” refers to
Specifically, a general formula CH ₂ ＣＲCR ₁ —COOR ₂ (where R ₁ represents hydrogen or a methyl group, and R ₂ has 1 to 1 carbon atoms)
Indicate 18 alkyl groups. (Meth) acrylic acid esters (meaning acrylic acid esters and / or methacrylic acid esters, and hereinafter mutatis mutandis applying the same chemical substance names), styrenes such as styrene and α-methylstyrene The aromatic ring of these styrenes has 1 to 4 carbon atoms.
And carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate. Among them, (meth) acrylic acid esters in which R ₂ is an alkyl group having 4 to 8 carbon atoms, such as butyl (meth) acrylate, cyclohexyl (meth) acrylate, ethylhexyl (meth) acrylate, styrenes, and styrene-based compounds Are preferred. Any of these may be used in combination of at least two of them. The amount of the component (b) used is from the above (a) to
(C) or the total of the monomers (a) to (d), that is, 3 to 20 mol% of 100 mol%, preferably 5 to
15 mol%. When the content is less than 3 mol% or more than 20 mol%, even if the other components (a) and (c) to (f) are within a predetermined range, the copolymer (B) obtained by this method is contained. Even if the rosin-based material is emulsified in the aqueous dispersion medium, the emulsifiability becomes poor.

The "(c) monomers containing a carboxylic acid group and / or a salt thereof" are monomers having at least one of a carboxyl group and a salt thereof, and include a monobasic carboxylic acid monomer and a dibasic carboxylic acid monomer. Polycarboxylic acid monomers such as basic carboxylic acid monomers and salts thereof (in the case of polyvalent carboxylic acid monomers, some or all of them are salts); Can be used together. Examples of the monobasic carboxylic acid monomers include (meth) acrylic acid and crotonic acid. Examples of the dibasic carboxylic acid monomers include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like. The carboxylic acid group-containing monomer has better copolymerizability than the above-mentioned salt of the monomer, and the component (B) containing the copolymer contains an emulsion obtained by emulsifying a rosin-based substance in an aqueous dispersion medium. It is preferable because the size effect of the agent is excellent. A sizing agent containing an emulsion obtained by emulsifying a rosin-based substance by the above (B) containing the above copolymer obtained by using a dibasic carboxylic acid monomer as the component (c) is used in a papermaking system. The use of the dibasic carboxylic acid monomers is preferred since the foaming property caused by the dispersant can be significantly reduced and the suitability for inkjet printing can be particularly improved. Among them, the above effect when using itaconic acid is most remarkable, and its use is preferable. (C)
The amount of the component used is 6 to 40 mol%, preferably 10 to 3 mol% of the whole monomers (a) to (c) or (a) to (d).
5 mol%. When the content is less than 6 mol% or more than 40 mol%, even if the other components (a), (b) and (d) to (f) are within a predetermined range, the copolymer obtained therefrom is contained. Even if the rosin-based substance is emulsified in the aqueous dispersion medium with the component (B), the emulsifiability deteriorates, and if it exceeds 40 mol%, the stability of the emulsion obtained by the emulsification further deteriorates.

The term "(d) monomers containing a sulfonic acid group and / or a salt thereof" refers to monomers having at least one of a sulfonic acid group and a salt thereof, and specifically, styrenesulfonic acid. , Vinyl sulfonic acid, 2-
Examples thereof include (meth) acrylamide-2-methylpropanesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, and alkali metal salts such as sodium and potassium, and ammonium salts thereof. At least one of these is used. (D)
The amount of the component used is 0.5 to 5 mol% of the whole monomers (a) to (d). Less than 0.5 mol%, 5 mol%
(A) to (c), (e), (f)
Is within a predetermined range, the emulsifiability is poor even when the rosin-based substance is emulsified in an aqueous dispersion medium with the component (B) containing the copolymer obtained therefrom, and the emulsion obtained by the emulsification is poor. The mechanical stability of the sizing agent contained in the papermaking system deteriorates.

Further, "(e) water-soluble mercaptans",
The “(f) poorly water-soluble mercaptans” are classified based on their solubility in water, and those having high solubility are referred to as (e), and those having low solubility are referred to as (f).
Specific examples of component (e) include mercaptans having 2 or 3 carbon atoms, such as mercaptoethanol, cysteamine hydrochloride, mercaptopropionic acid, its salts, thioglycolic acid, its salts, thioacetic acid, and its salts. These can be used alone or in combination of at least two of them. Specific examples of (f) include n-octyl mercaptan, n-dodecyl mercaptan, mercaptan compounds having 4 to 18, preferably 8 to 16 carbon atoms, octyl mercaptopropionate, methoxybutyl mercaptopropionate, Examples thereof include butyl glycolate, methoxybutyl thioglycolate, octyl thioglycolate, thiophenol, thiobenzoic acid, and thiosalicylic acid. (E),
The component (f) is (a) to (c) or (a) to
0.2 to 100 mol% of the total of the monomers (d)
3 mol%. If the amount is less or more than this, the emulsifying and dispersing ability of the component (B) in the aqueous dispersion medium with respect to the component (A) and the sizing performance of the sizing agent containing the emulsion are inferior. Foamability in the system increases.

In view of the emulsifying and dispersing ability of the component (B) in the aqueous dispersion medium with respect to the component (A), the stability of the emulsion as the emulsion, and the sizing performance of the sizing agent containing the emulsion, the above (e) ) And (f), each having at least one type of mercaptan having different properties, that is, at least two types of mercaptans. The combination ratio of (e) and (f) is (e) / (f) = 0.07-15, preferably 0.1-3. A copolymer obtained by polymerizing only one of (e) and (f) together with the above (a) to (c) or (a) to (d) is prepared in the same manner except that both of these are used. Compared to the obtained copolymer, the above-mentioned emulsifying and dispersing ability and sizing performance are inferior, and the foamability in a papermaking system using the sizing agent is increased.

When at least one of the components (a) to (f) is out of the above-mentioned predetermined range, when the copolymer obtained as described above is used as an emulsifying dispersant, rosin to an aqueous dispersion medium is used. In some cases, problems such as insufficient emulsifying and dispersing power of the system material may occur.However, even when the emulsifying and dispersing power is present, the sizing effect of the sizing agent containing the emulsion that is the emulsified solution, Stability,
The storage stability and the foaming property of the papermaking system are inferior, and the ink-jet printability of paper made using the sizing agent is also inferior, so that the effects of the present invention cannot be obtained.

The above (a) to (b) contained in the above component (B)
In order to synthesize a copolymer obtained by polymerizing at least (c), (e) and (f), or (a) to (f), a conventional method such as solution polymerization, emulsion polymerization, dispersion polymerization or precipitation polymerization is used. Known methods can be applied. For example, in the case of solution polymerization, the monomer to be copolymerized is methyl alcohol,
At least one kind of lower alcohols such as ethyl alcohol, isopropyl alcohol and tertiary butyl alcohol, at least one kind such as acetone, methyl ethyl ketone and dioxane, in other organic solvents, or in a mixture of these organic solvents and water The polymerization is performed by adding a radical polymerization catalyst in the above step.After the polymerization is completed, water is added if only an organic solvent is used, and if the solvent is used in combination with water, the organic solvent is partially or almost completely distilled off. As a result, an aqueous solution or an aqueous dispersion is obtained. In addition, precipitation polymerization is a case where a copolymer formed during polymerization is insolubilized and precipitated by the selection of a solvent for a polymerization system, and the precipitate is separated by filtration and dissolved or dispersed in water. A dispersion stabilizer such as polyvinyl alcohol and (meth) acrylic acid homopolymer and / or copolymer dissolved in a solvent used for the system is added to the polymerization system in advance, the polymer is maintained in a dispersed state, and water is added. To dissolve or maintain a dispersed state. In the case of emulsion polymerization, it is a method of dispersing a monomer to be copolymerized in water in the presence of a known anionic and / or nonionic surfactant and polymerizing with a radical polymerization catalyst. At this time, it is also possible to perform polymerization without using an emulsifier, that is, using a polymerized polymer as an emulsifier without adding a surfactant.

The above radical polymerization catalysts include, for example, persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate; redox-based polymerization catalysts obtained by combining these persulfates and a reducing agent; An azo catalyst such as azobisisobutyronitrile can be used.

In the obtained copolymer, a carboxylic acid group in the copolymer can be converted into a salt, if necessary. In addition to the above components (a) to (f), other salts may be used. Although this may be done, it is preferable to have a free carboxylic acid group in view of the above-mentioned dispersing ability, size effect, ink jet suitability, and foamability. Examples of other monomers added in a range that does not cause any trouble other than the above components (a) to (f) include, for example, cationic monomers, and specifically, aminoalkyl (meth) acrylate and aminohydroxyalkyl (meth) acrylate , Aminoalkyl (meth)
Acrylamide, aminohydroxylalkyl vinyl ether, vinylpyridine, vinylimidazole, diallylamine and the like, and furthermore, quaternary ammonium salts thereof. These may be used alone or in combination with at least two kinds of (a)
It is at most 10 mol% with respect to 100 mol% of the monomers of (c) or (a) to (d).

The above-obtained copolymer thus obtained is
In the case of precipitation polymerization, it is separated by filtration and water is added to obtain an aqueous solution or an aqueous dispersion. Others are an aqueous solution or an aqueous dispersion as described above, but a part of the organic solvent used during the polymerization may remain. The viscosity of the aqueous solution is preferably in the range of 500 to 30,000 centipoise in a 35% by weight aqueous solution of solid content (viscosity measurement is a value measured at 25 ° C. by a Brookfield viscometer). When the viscosity is out of this range, it may be difficult to maintain the dispersing ability of the emulsifying dispersant containing the copolymer in an aqueous medium with respect to a rosin-based substance, or the storage of a sizing agent containing the emulsion may be difficult. It may be difficult to maintain stability and mechanical stability.

The sizing agent of the present invention comprises the above component (A),
(A) to (c), (e) and (f), or (a) to
The component (B) contains a copolymer obtained by polymerizing (f) at least, and the rosin-based substance of the component (A) and the copolymer of the component (B) are used in an amount of this ( It is preferable that the emulsion obtained by emulsifying and dispersing the component (A) in the aqueous dispersion medium with the component (B) is stable for a long period of time, and that the sizing agent containing the emulsion exerts its effect sufficiently. From this perspective,
The copolymer is 1 to 30%, preferably 3 to 20% by weight based on the total solid content (the total of the emulsifying dispersant and the rosin-based substance).
Is preferable. If it is less than 1% by weight, the dispersing ability is not sufficient, and the stability of the obtained emulsion may not be good. Use in excess of 30% by weight is economically disadvantageous, and the resulting sizing agent may have too high a viscosity or too high a foaming property.

The method for preparing the sizing agent of the present invention is not particularly limited. For example, as described in JP-B-54-36242, the rosin-based substance (A) is dissolved in an oil-soluble solvent in advance. The mixed solution, the emulsifying dispersant (B) containing the above copolymer and water are mixed and treated with a homogenizer, and then the solvent is distilled off to produce an oil-in-water emulsion, the so-called solvent method, JP-B-53-32380. As described in the official gazette, the molten rosin-based material (A) is mixed with the emulsifying dispersant (B) containing the copolymer and water under high temperature and high pressure, and the mixture is passed through a homogenizer to form an oil-in-water emulsion. As described in the so-called high-temperature and high-pressure method (mechanical method) for producing the rosin-based substance (A), the above-mentioned copolymer is contained in the molten rosin-based substance as described in JP-A-52-77206. The emulsifying dispersant of (B) and a part of water are mixed with stirring, and further water is added to form a water-in-oil emulsion. Then, a large amount of water is added to invert the emulsion, and the phase is changed to an oil-in-water emulsion. A so-called phase inversion method is used.

Since the copolymer contained in the component (B) has a high ability to disperse the rosin-based substance of the component (A) in water, the component (A) is converted into an aqueous medium by the component (B). In preparing a rosin emulsion by emulsification and dispersion, any of the above-mentioned solvent method, mechanical method, and phase inversion method can be adopted. In addition, a known surfactant or a high molecular weight copolymer may be contained in advance in (B) within a range that does not impair the emulsifying and dispersing effect of the above copolymer, or a sizing agent may be used as a component other than (B). However, in such a case, it can be used in an amount of 0.1 to 1.0% by weight based on the rosin-based substance as the component (A). Examples of such a surfactant that can be used in combination include cationic surfactants such as alkylamine salts, quaternized products thereof, and polyoxyalkylenealkylamine ethers. Examples of nonionic compounds include polyoxyalkylene phenyl ether, polyoxyalkylene alkyl ether, various sorbitan emulsifiers, polyoxyalkylene block copolymers, and polyoxyalkylene-added rosin esters. Anionic ones are alkali-neutralized salts of rosin and fortified rosin, alkylbenzene sulfonates,
Polyoxyalkylene alkyl phenyl ether sulfate, alkyl sulfate, naphthalene sulfonate, AS
Alkaline salts of A (alkenyl succinic anhydride), polyoxyalkylene alkyl ether sulfates, sulfosuccinates and the like can be mentioned. Examples of the polymer copolymer include a dispersant and a (meth) acrylamide dispersant obtained by neutralizing a copolymer of a styrene monomer and a (meth) acrylic acid monomer.

The emulsion obtained by emulsifying and dispersing the above component (A) with the component (B) in an aqueous dispersion medium has an average particle size (cumulative 50% size in a weight-based particle size distribution) of 1 μm.
m (at most 1 μm), preferably 0.5 μm or less (at most 0.5 μm). When the particle size exceeds 1 μm, a precipitate is easily formed during storage, and mechanical stability may not be good. The average particle diameter can be measured by, for example, a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.). The aqueous dispersion medium is not limited to water alone, and may contain a soluble component such as an organic solvent and a salt.

In the sizing method of the present invention, a sizing agent containing a rosin emulsion obtained by emulsifying and dispersing the above-mentioned component (A) in an aqueous dispersion medium with the component (B) is added to, for example, a wet end portion during papermaking. It is implemented by doing. Specifically, the sizing agent is added to an aqueous dispersion of pulp in an amount of 0.02 to 10% by solids, preferably 0.05 to 5% by solids, based on the dry weight of the pulp. The pH of the pulp slurry at the time of the addition is 5.0 to 9.
It is preferably used in a weakly acidic or alkaline region of 0, but may be used in other regions.

The sizing paper obtained by using the above-mentioned sizing agent is not particularly limited, but includes various types of paper and paperboard. Paper types include PPC paper, inkjet printing paper, laser printer paper, foam paper, thermal transfer paper, heat-sensitive recording paper, pressure-sensitive recording paper, and other recording paper, such as paper, art paper, cast-coated paper, and high-quality coated paper. Wrapping paper such as coated base paper, kraft paper, pure white roll paper, and other paper (paper) such as notebook paper, book paper, various printing papers, newsprint paper, paperboards for paper containers such as manila balls, white balls, chip balls, Paperboard such as a liner is included. The sizing agent of the present invention also includes a surface sizing agent as a subordinate concept. When used as a surface sizing agent, the sizing agent is applied to a wet paper made in advance by a conventional method such as spraying, dipping, or coating.

In producing the various papers and paperboards described above, pulp raw materials include bleached or unbleached chemical pulp such as kraft pulp and sulfite pulp, bleached chemical pulp, groundwood pulp, mechanical pulp, and thermomechanical pulp. Either bleached high yield pulp, waste paper pulp such as newspaper waste paper, magazine waste paper, cardboard waste paper, deinked waste paper, or the like can be used.

To obtain the sizing paper of the present invention, a filler,
Additives such as dye, aluminum sulfate, dry paper strength improver, wet paper strength improver, retention improver, drainage improver, etc.
It may be used as needed to achieve the physical properties required for each paper type. As the filler, heavy or light calcium carbonate is mainly used, but clay and talc are also used, and these may be used in combination. Examples of the dry paper strength improver include anionic polyacrylamide-based polymers, cationic polyacrylamide-based polymers, amphoteric polyacrylamide-based polymers (copolymers with other vinyl monomers, each of which is mainly (meth) acrylamide,
The same applies hereinafter), cationized starch, amphoteric starch and the like.
These may be used alone or in combination. Examples of the wet paper strength improver include polyamide / epichlorohydrin resin. These may be used alone or in combination with an anionic polyacrylamide polymer. Examples of the retention aid include an anionic or cationic high molecular weight polyacrylamide polymer, a combination of silica gel and cationized starch, and a combination of bentonite and a cationic high molecular weight polyacrylamide polymer. In addition, starch, polyvinyl alcohol, etc., with a size press, gate roll coater, bill blade coater, calender, etc.
Dyes, coating colors, surface sizing agents, anti-slip agents and the like may be applied as necessary.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail with reference to the following examples, which are summarized and expanded to the scope of the same effect as acrylamide 40 to 85 mol%,
Isobutyl methacrylate and cyclohexyl methacrylate as hydrophobic monomers are each 8 to 17 mol%, and carboxylic acid group-containing monomers are acrylic acid, maleic anhydride and itaconic acid each at 8 to 30 mol%.
Of thioglycolic acid, 2-mercaptoethanol and mercaptopropionic acid as water-soluble mercaptans in an amount of 0.3 to 1.8 mol%, and n-dodecylmercaptan and n-dodecylmercaptan as hardly water-soluble mercaptans, respectively, based on a total of 100 mol%. -0.2 of each of the octyl mercaptans
(A) to (c), (e) and (f) in an aqueous medium (a mixture of water and an organic solvent soluble in water) at 40 to 100 ° C. Case). Acrylamide 60 to 90 mol%, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, a combination of styrene and butyl acrylate, a combination of styrene and methyl methacrylate 3 to 20 mol% as hydrophobic monomers, carboxylic acid group-containing monomers Of methacrylic acid, maleic anhydride, and itaconic acid in an amount of 6 to 25 mol%, and sodium sulfonic acid group-containing monomers of sodium vinyl sulfonate, sodium styrene sulfonate, and 2-acrylamido-2-methylpropanesulfonic acid each as 0%. For each of the total mol ratios of 0.8 to 5 mol%, cysteamine hydrochloride, 2-mercaptoethanol, mercaptopropionic acid and thioacetic acid were each added in an amount of 0.2 to 5 mol% as water-soluble mercaptans.
An aqueous medium (a mixture of water and an organic solvent soluble in water) containing 1.2 mol% of a monomer composed of 0.2 to 3.0 mol% of each of n-dodecyl mercaptan and n-octyl mercaptan as poorly water-soluble mercaptans. Medium, 40-100
Polymerization at a temperature of (° C) ((a) to (d), (e) and (f)). 15 to 25 parts by weight of the copolymer solution (35% by weight solution) thus obtained was used as a rosin-based substance to enhance fumaric acid fortified with gum rosin (degree of fortification 5 to 15%).
00 parts by weight, a maleic anhydride fortified gum rosin (strength of 5 to 15%) and a rosin esterified product in a weight ratio of 90:
10 to 40:60, 100 parts by weight in total, 100 parts by weight of a rosin esterified product, a maleic anhydride fortified gum rosin and a rosin esterified product in a weight ratio of 20:80 to
A total of 100 parts by weight of 40:60 was emulsified and dispersed in an aqueous dispersion medium (water) by a phase inversion method or a mechanical method to obtain a solid content of 40 to 50% by weight and an average particle size of 0.25 to 0.45 μm.
A rosin emulsion is obtained, which is used as a sizing agent. In the case of a sizing paper made with this sizing agent at a papermaking pH of 5.0 to 8.0, the Stöckigt sizing degree is 10 to 25.
Seconds can be set, and in that case,
25 seconds, especially 18 to 25 seconds when itaconic acid is used as the component (b), 15 to 25 seconds in the above case, particularly 18 to 2 seconds when itaconic acid is used as the component (b)
5 seconds. In addition, the suitability of the sizing paper for inkjet printing is such that the print density can be set to 1.20 to 1.32, and among them, in the above case, it is 1.25 to 1.3.
0, particularly 1.29 to 1.30 when itaconic acid is used as the component (b), and 1.26 to 1.3 in the above case.
2, especially when itaconic acid is used as the component (b), the ratio is 1.29 to 1.32, the feathering can be set to 4 or 5, and the strike-through can be set to 4 or 5; b) feathering when itaconic acid is used as a component,
The strike-through can be set to 5. Further, the toner fixing property of the sizing paper can be 0.88 to 0.92. Furthermore, static stability is less than 1 mm, mechanical stability is 0.1-0.2%, foaming property is 0-35%, redispersibility can be 4 or 5, mechanical stability, foaming. Particularly preferred in terms of properties and redispersibility is the case where itaconic acid is used as the component (b).

[0031]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. All parts and percentages below are by weight unless otherwise specified. Production Example 1 of Copolymer Solution (Copolymer Solution for Examples (G-
Production of 1)) In a 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 228 parts (80 mol%) of a 50% aqueous acrylamide solution, 28 parts of isobutyl methacrylate as a hydrophobic monomer ( 10 mol%), and 14 parts (10%) of acrylic acid as carboxylic acid group-containing monomers.
Mol.), 136 parts of ion-exchanged water, 218 parts of isopropyl alcohol, 0.9 part (0.5 mol%) of thioglycolic acid as a water-soluble mercaptan, and 2.8 parts of n-dodecyl mercaptan as a poorly water-soluble mecaptan (0 part). (0.7 mol%), and the mixture was heated to 60 ° C. in a nitrogen gas atmosphere while stirring. Then, 0.3 parts of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, the temperature was raised to 80 ° C., and this temperature was maintained for 5 hours.
Next, isopropyl alcohol was distilled off, and ion-exchanged water was added to prepare a copolymer solution (G-1) having a solid content of 35% and a viscosity of 800 centipoise (cps). The viscosity was measured using a Brookfield viscometer.
The viscosity was measured at 25 ° C. (hereinafter, viscosity measurement conditions are the same).

Production Example 2 of Copolymer Solution (Production of Copolymer Solution for Example (G-2))
Parts (70 mol%), 28 parts (20 mol%) of acrylic acid, and 2.7 parts (1.5 mol%) of thioglycolic acid.
%, A copolymer solution (G-2) having a viscosity of 1000 cps was prepared.

Preparation Example 3 of Copolymer Solution (Preparation of Copolymer Solution (G-3) for Example)
Part (70 mol%), 34 parts (10 mol%) of cyclohexyl methacrylate instead of isobutyl methacrylate as the hydrophobic monomer, and 39 parts (2 parts) of maleic anhydride instead of acrylic acid as the carboxylic acid group-containing monomer.
0 mol%), 0.8 parts (0.5 mol%) of 2-mercaptoethanol instead of thioglycolic acid as water-soluble mercaptans, and n-
1.5 parts (0.5 mol%) of n-octyl mercaptan was used in place of dodecyl mercaptan, and AIBN
The polymerization reaction was carried out in the same manner except that 2.3 parts of was used, to produce a copolymer solution (G-3) having a solid content of 35% and a viscosity of 700 cps.

Production Example 4 of Copolymer Solution (Production of Copolymer Solution for Example (G-4))
Parts (88 mol%), 2-ethylhexyl methacrylate 12 parts (3 mol%) instead of isobutyl methacrylate as hydrophobic monomers, and itaconic acid 16 parts (6 mol%) instead of acrylic acid as carboxylic acid group-containing monomers 8 parts (3 mol%) of sodium vinyl sulfonate as sulfonic acid group-containing monomers,
5 parts, 227 parts of isopropyl alcohol, 2.3 parts (1.0 mol%) of cysteamine hydrochloride instead of thioglycolic acid as a water-soluble mercaptan, n-dodecyl mercaptan as a poorly water-soluble mercaptan
A polymerization reaction was carried out in the same manner except that 1.5 parts (0.5 mol%) of octyl mercaptan was used and 0.7 part of AIBN was used, and the solid content was 35% and the viscosity was 3500 cp.
s was prepared as a copolymer solution (G-4).

Production Example 5 of Copolymer Solution (Production of Copolymer Solution (G-5) for Example) In Production Example 3, 52 parts of itaconic acid were used as the carboxylic acid group-containing monomers in place of maleic anhydride. (20
Mol%), except that it was used.
A copolymer solution having 35% solids and a viscosity of 5500 cps (G
-5) was manufactured.

Preparation Example 6 of Copolymer Solution (Production of Copolymer Solution for Example (G-6))
(67 mol%), and a polymerization reaction was carried out in the same manner except that sodium styrenesulfonate was newly added as a sulfonic acid group-containing monomer (12 mol (3 mol%)) to obtain a solid content of 35% and a viscosity of 5000 cps. A copolymer solution (G-6) was produced.

Preparation Example 7 of Copolymer Solution (Production of Copolymer Solution (G-7) for Example)
Parts (45 mol%), 50 parts (15 mol%) of cyclohexyl methacrylate instead of isobutyl methacrylate as hydrophobic monomers, and 104 parts (40 mol) of itaconic acid instead of acrylic acid as monomers containing carboxylic acid groups.
Mol%), 291 parts of ion-exchanged water, 309 parts of isopropyl alcohol, 1.5 parts (0.7 mol%) of mercaptopropionic acid instead of thioglycolic acid as water-soluble mercaptans, and n-type as hardly water-soluble mercaptans
A polymerization reaction was carried out in the same manner except that 1.2 parts (0.3 mol%) of dodecyl mercaptan and 2.3 parts of AIBN were used, and the solid content was 35% and the viscosity was 4800 cp.
s was prepared as a copolymer solution (G-7).

Production Example 8 of Copolymer Solution (Production of Copolymer Solution for Example (G-8))
Parts (65 mol%), 17 parts (8 mol%) of styrene instead of isobutyl methacrylate as hydrophobic monomers
And 5 parts (2 mol%) of butyl acrylate, 39 parts (20 mol%) of maleic anhydride instead of acrylic acid as a carboxylic acid group-containing monomer, and 2-acrylamide-2-methylpropane as a new sulfone group-containing monomer. Sulfonic acid 21 parts (5 mol%), ion-exchanged water 186
Parts, isopropyl alcohol 244 parts, water-soluble mercaptans instead of thioglycolic acid 0.8 parts (0.4 mol%) mercaptopropionic acid, n-dodecyl mercaptan 12 parts (3 mol%) as poorly water-soluble mercaptans. The polymerization reaction was carried out in the same manner except that 2.3 parts of AIBN were used.
A 500 cps copolymer solution (G-8) was produced.

Production Example 9 of Copolymer Solution (Production of Copolymer Solution for Example (G-9)) A 1-liter four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was prepared. 196 parts (69 mol%) of a 50% aqueous solution of acrylamide, 20 parts (10 mol%) of styrene as hydrophobic monomers and 20 parts (10 mol%) of methyl methacrylate, 17 parts (10 mol%) of methacrylic acid as carboxylic acid group-containing monomers %), 4 parts (1 mol%) of sodium styrenesulfonate as sulfonic acid group-containing monomers, 273 parts of ion-exchanged water, 3.8 parts (2.5 mol%) of thioacetic acid as water-soluble mercaptans,
A mixture of 6.0 parts (1.5 mol%) of n-dodecyl mercaptan and 3 parts of ammonium dodecylbenzenesulfonate as poorly water-soluble mecaptans was heated to 70 ° C., and 11 parts of ammonium persulfate was added. The reaction was carried out for an hour to produce a copolymer solution (G-9) having a solid content of 30% and a viscosity of 18,000 cps.

Production Example 10 of Copolymer Solution (Production of Copolymer Solution (G-10) for Comparative Example) The same procedure as in Production Example 1 was conducted except that thioglycolic acid as a water-soluble mercaptan was not used. To carry out a polymerization reaction to produce a copolymer solution (G-10) having a solid content of 35% and a viscosity of 9,500 cps.

Production Example 11 of Copolymer Solution (Production of Copolymer Solution (G-11) for Comparative Example) In Preparation Example 1, except that n-dodecyl mercaptan was not used as a poorly water-soluble mecaptan. A polymerization reaction was carried out in the same manner, and the solid content was 35% and the viscosity was 5400.
A cps copolymer solution (G-11) was prepared.

Production Example 12 of Copolymer Solution (Production of Copolymer Solution for Comparative Example (G-12)) In Production Example 6 described above, 0.8 part (0 part) of 2-mercaptoethanol as a water-soluble mercaptan was used. 0.5 mol%)
The polymerization reaction was carried out in the same manner except that 5.5 parts (3.5 mol%) were used instead of
A cps copolymer solution (G-12) was prepared.

Production Example 13 of Copolymer Solution (Production of Copolymer Solution (G-13) for Comparative Example) In Production Example 6, 1.5 parts (0 parts) of n-octyl mercaptan as a poorly water-soluble mercaptan was used. Polymerization reaction was carried out in the same manner except that 10.5 parts (3.5 mol%) was used instead of (0.5 mol%) to obtain a copolymer solution (G-13) having a solid content of 35% and a viscosity of 3600 cps. Manufactured.

Production Example 14 of Copolymer Solution (Production of Copolymer Solution (G-14) for Comparative Example)
Part (96 mol%), 12 parts (3 mol%) of 2-ethylhexyl methacrylate instead of isobutyl methacrylate as a hydrophobic monomer, 1 part (1 mol%) of acrylic acid as a carboxylic acid group-containing monomer, and 1 part of ion-exchanged water.
02 parts, 209 parts of isopropyl alcohol, 1.1 parts (0.7 mol%) of 2-mercaptoethanol instead of thioglycolic acid as water-soluble mercaptans, and 2 parts (0.5 part) of n-dodecyl mercaptan as poorly water-soluble mercaptans (Mol%), and a polymerization reaction was carried out in the same manner as described above to produce a copolymer solution (G-14) having a solid content of 35% and a viscosity of 900 cps.

Preparation Example 15 of Copolymer Solution (Preparation of Copolymer Solution (G-15) for Comparative Example)
Parts (38 mol%), 51 parts (18 mol%) of isobutyl methacrylate as a hydrophobic monomer, and itaconic acid 1 instead of acrylic acid as a carboxylic acid group-containing monomer.
04 parts (40 mol%), 16 parts (4 mol%) of sodium styrenesulfonate as sulfonic acid group-containing monomers, 306 parts of ion-exchanged water, 315 parts of isopropyl alcohol, and water-soluble mercaptans instead of thioglycolic acid 1.9 parts (1.2 mol%) of 2-mercaptoethanol, n- as a poorly water-soluble mercaptan
A polymerization reaction was carried out in the same manner except that 3.2 parts (0.8 mol%) of dodecyl mercaptan and 2.3 parts of AIBN were used, and a copolymer solution having a solid content of 35% and a viscosity of 2800 cps (G- 14) was produced.

Production Example 16 of Copolymer Solution (Production of Copolymer Solution (G-16) for Comparative Example)
Parts (82 mol%), 4 parts (3 mol%) of acrylic acid as a carboxylic acid group-containing monomer, and 21 parts (5 mol%) of 2-acrylamido-2-methylpropanesulfonic acid as a new sulfonic acid group-containing monomer , Ion exchange water 15
Polymerization reaction was carried out in the same manner except that 4 parts, 237 parts of isopropyl alcohol, and thioglycolic acid as a water-soluble mercaptan were not used, and a copolymer solution (G-16) having a solid content of 35% and a viscosity of 25,000 cps was prepared. Manufactured.

Production Example 17 of Copolymer Solution (Production of Copolymer Solution (G-17) for Comparative Example)
Parts (45 mol%), 65 parts (45 mol%) of acrylic acid as carboxylic acid group-containing monomers, 214 ion-exchanged water
Parts, 231 parts of isopropyl alcohol, and 2.7 parts (1.5 mol%) of thioglycolic acid as a water-soluble mercaptan, and the polymerization reaction was carried out in the same manner. A copolymer having a solid content of 35% and a viscosity of 35,000 cps was used. Combined solution (G
-17).

Production Example 18 of Copolymer Solution (Production of Copolymer Solution (G-18) for Comparative Example)
Parts (89 mol%) and 8 parts (2-mol%) of 2-ethylhexyl methacrylate as the hydrophobic monomer, the polymerization reaction was carried out in the same manner, and a copolymer solution having a solid content of 35% and a viscosity of 2400 cps ( G-17).

Production Example 19 of Copolymer Solution (Production of Copolymer Solution (G-19) for Comparative Example) In Production Example 7, cyclohexyl methacrylate was used as the hydrophobic monomer in place of 50 parts (15 mol%). The polymerization reaction was carried out in the same manner except that 84 parts (25 mol%) and 78 parts (30 mol%) of itaconic acid as the carboxylic acid group-containing monomers were used instead of 104 parts (40 mol%). 35% solids, viscosity 42000 cps
Was prepared as a copolymer solution (G-19).

Tables 1 and 2 show the compositions of the copolymers prepared in the above Examples and Comparative Examples, and the viscosities of the solutions.
Are shown together.

[Table 1]

[0051]

[Table 2]

Production Example 1 of Rosin-Based Substance (Production Example of Fumaric Acid Reinforced Gum Rosin (H)) 80 parts of fumaric acid was gradually added to 920 parts of gum rosin in a molten state at about 200 ° C. The mixture was heated for a period of time to obtain a fumaric acid fortified gum rosin (H). The toughening degree (addition rate of fumaric acid) of this fortified material was 8%.

Production Example 2 of Rosin-Based Substance (Production Example of Maleic Anhydride Enriched Gum Rosin (I)) To 900 parts of gum rosin in a molten state at about 200 ° C., 100 parts of maleic anhydride was gradually added, and the same temperature was applied. For 3 hours to obtain a maleic anhydride-enriched gum rosin (I). The toughening degree (addition ratio of maleic anhydride) of this toughened product was 10%.

Production Example 3 of Rosin-Based Substance (Production Example of Rosin Ester (J)) In a flask equipped with a stirrer, thermometer, nitrogen inlet tube, water separator and cooler, 600 parts of gum rosin having an acid value of 170 were added. 56 parts of glycerin (charge molar ratio is -OH / -COOH =
1.0), heated to 270 ° C. under a nitrogen stream, and reacted at the same temperature for 15 hours with stirring to obtain a rosin esterified product (J) having an acid value of 13.

Production Example 4 of Rosin-Based Substance (Production Example of Enhanced Rosin Ester (K))
A rosin esterified product having an acid value of 36 was obtained in the same manner except that the charging ratio of 0 parts and 45 parts of glycerin was changed (the charging molar ratio was -OH / -COOH = 0.8). Then, after 485 parts of this rosin esterified product was heated to 200 ° C., 15 parts of maleic anhydride was added with stirring, and the mixture was heated at the same temperature for 3 hours to obtain a rosin ester maleic anhydride fortified product (K). The toughening degree (addition ratio of maleic anhydride) of this fortified rosin ester was 3%.

Example 1 (Production Example 1 of rosin emulsion sizing agent) 100 parts of fumaric acid fortified substance (H) of gum rosin of Production Example 1 of the above-mentioned rosin-based material was heated and melted at about 150 ° C, and the above mixture was stirred. The copolymer solution (G-
20 parts of 1) were added and mixed, followed by phase inversion while further adding hot water to obtain a water-in-oil type emulsion. Hot water was quickly added thereto to obtain a stable oil-in-water emulsion. Cooled down. The rosin emulsion thus obtained has a solids content of 45.3% and an average particle size of 0.35%.
μm. This rosin emulsion is directly used as a sizing agent.

Examples 2 to 11 (Production Examples 2 to 11 of rosin emulsion sizing agent) Fumic acid fortified gum rosin (H) and gum rosin fortified with maleic anhydride (Production Examples 1 to 4) I), the rosin esterified product (J), the reinforced rosin esterified product (K) and the copolymer solutions (G-1) to (G-9) of the above copolymer solution production examples 1 to 9 are shown in Table 2 respectively. According to the combination and the charging ratio shown in the column of Examples, the solid content of each column shown in Table 3 in the same manner as in Example 1 except that 100 parts of the rosin-based material and 20 parts of the copolymer solution were used. A rosin emulsion having an average particle diameter is prepared, and each is used as a sizing agent of the corresponding example.

Comparative Examples 1 to 10 (Production Examples 1 to 10 of Comparative Rosin Emulsion Sizing Agent) Fumic acid fortified product of gum rosin (H) and gum rosin fortified with maleic anhydride of Production Examples 1 to 3 of the above rosin-based substances (I), rosin esterified product (J) and copolymer solutions (G-10) to (G-
19) in the same manner as in Example 1 except that 100 parts of the rosin-based substance and 20 parts of the copolymer solution were used in accordance with the combinations and the charging ratios shown in the columns of Comparative Examples in Table 2. A rosin emulsion having a solid content and an average particle diameter shown in the column of Comparative Example is produced, and each is used as a sizing agent of the corresponding comparative example.

Example 12 (Production Example 12 of Rosin Emulsion Sizing Agent) 30 parts of maleic anhydride fortified gum rosin (I) of Production Example 2 of the rosin-based material and Production Example 4 of the rosin-based material
Of reinforced rosin esterified product (K) of about 70 ° C.
Then, with stirring, 20 parts of the copolymer solution (G-9) for the example of the copolymer solution production example 9 and water 130 were stirred.
Parts under high temperature and high pressure, and the mixture is
After passing through an industrial homogenizer at a pressure of / cm ² , the mixture was cooled to room temperature. The solid content of the emulsion thus obtained was 45.4%, and the average particle size was 0.38 μm.
This is used as it is as a sizing agent.

[0060]

[Table 3]

Application Examples 1 to 12, Application Comparative Examples 1 to 11
(Examples of sizing method and sizing paper) Paper making was performed under the following conditions using each sizing agent of Examples 1 to 12, Comparative Examples 1 to 10, and alkyl ketene dimer sizing agent (Comparative Example 11). The sizing method using a sizing agent is carried out under an environment of constant temperature and humidity (20 ° C., 65% relative humidity).
The following test was performed on the test paper obtained by controlling the humidity for 4 hours. (A) Handmaking test A 380 ml pulp beaten to Canadian Standard Freeness (mixed pulp having a pulp ratio of hardwood to softwood of 9: 1) was used as a 2.5% slurry, and this was mixed with 2% of pulp ( Calcium carbonate (TP121S, manufactured by Okutama Kogyo Co., Ltd.) was added. A sulfuric acid band of 1% based on pulp (based on absolute dry weight), an amphoteric starch (manufactured by Oji National Co .; Cato3210) of 0.5% based on pulp (based on absolute dry weight) and 0.3% based on pulp
After adding the sizing agent (absolute dry basis) obtained in Example 1 above, the pulp concentration was 0.25 with diluted water having a pH of 7.5.
%. Thereafter, calcium carbonate (manufactured by Okutama Industry Co., Ltd .; TP121S) and pulp 0.01% retention improver (manufactured by Himo Co .; NR12MLS) were added to the diluted pulp slurry by 8% based on pulp (absolute dry weight basis), Paper was made with a Noble and Wood paper machine to a basis weight of 65 g / m ² . The papermaking pH at this time was 7.5. Drying of the wet paper is performed using a drum dryer for 100 minutes.
C. for 80 seconds. After the obtained sizing paper was conditioned for 24 hours in a constant temperature and constant humidity (20 ° C., 65% relative humidity) environment, the Stigecht sizing degree of the test paper was measured.
The same papermaking was performed for each of the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 11, and the above Examples 2 to 12 and Comparative Examples 1 to 12 were performed.
The degree of Stekigt sizing was measured on the test paper sized with the sizing agent obtained in Example 10.

(B) Hand making test In the above hand making test, clay (manufactured by Nissei Kyoeki Co., Ltd .; Ayammela clay) was used in place of calcium carbonate, and the addition ratio of the sizing agent in each of Examples and Comparative Examples was set to 0. 0.2% (based on absolute dry weight), paper making was performed for each sizing agent in each of Examples and Comparative Examples in the same manner as in Examples 2 to 12,
The test paper sized with the sizing agents obtained in Comparative Examples 1 to 10 was measured for the degree of Stekigto sizing.
The pH during papermaking was 7.0.

(C) Hand-Making Test A pulp concentration of waste corrugated paper (containing 12% of filler) was used.
Using a beater, the mixture was beaten to 350 ml Canadian Standard Freeness with water for dilution having an amount of 5% and hardness of 100 ppm. To this, a sulfuric acid band of 1% (based on absolute dry weight) to pulp, a cationic polyacrylamide (manufactured by Nippon PMC; DS410) of 0.2% (based on absolute dry weight) and pulp 0.2% (based on pulp) After adding the sizing agent of Example 1 described above (based on absolute dry weight), the pH was adjusted to 6.
The diluted pulp was diluted with 0.2 dilution water to a pulp concentration of 0.25%. After that, the weight is 80 g / m ^{2 by} a Noble and Wood paper machine.
The paper was made so that The papermaking pH at this time was 5.
It was 7. Drying of the wet paper was performed using a drum dryer at 100 ° C. for 80 seconds. The obtained sized test paper is kept at a constant temperature and humidity (20 ° C., 65% relative humidity).
After conditioning for 24 hours in an environment, the degree of Stekigt sizing was measured. The same papermaking was performed for each of the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 10, and the Stigecht sizing degree of each sized test paper was measured. In the hand-making test, paper using the sizing agent of Comparative Example 11 was an alkyl ketene dimer sizing agent having a pulp concentration of 0.1% (manufactured by Nippon PMC; AS263).
Papermaking was carried out in the same manner as in the other cases except that was used.

(D) Evaluation of suitability for ink-jet printing The evaluation of suitability for ink-jet printing was performed by the above-mentioned hand-making test.
After the sizing paper obtained by making the paper using the sizing agents obtained in Examples 1 to 12 and Comparative Examples 1 to 10 is calendered, the temperature and humidity (20 ° C., 65% relative humidity)
After controlling the humidity for more than 24 hours under the environment, Canon Inc.
BJ-220JCII bubble jet printer
Was carried out by the following method. (D) -1 Print density test Solid printing was performed on test paper, and the print density of the solid portion was measured with a Macbeth ink densitometer. The higher the value, the higher the print density. (D) -2 Feathering test A straight line and a character having a constant line width perpendicular to the test paper were printed, and the bleeding of the outer edge of the straight line and the character was visually evaluated on a five-point scale. The sample having no feathering was designated as 5, and the sample having ink bleeding and the characters could not be identified was designated as 1.
The print quality that can withstand normal use is 4 or more. (D) -3 Print-through test Solid printing was performed on a test paper, and the degree of bleeding of the ink on the back side of the solid printed portion was visually evaluated on a scale of 5 levels. The sample with no ink bleeding on the back was designated as 5, and the sample with the solid portion completely penetrated was designated as 1. The print quality that can withstand normal use is 4 or more.

(E) Evaluation of suitability for PPC paper Evaluation of suitability for PPC paper was conducted by calendering a sized test paper obtained by making a paper in the above-described hand-making test, and then subjecting it to constant temperature and humidity (20 ° C., 65% (Relative humidity) After controlling the humidity for at least 24 hours in an environment, the following method was carried out using an electrophotographic copying machine RICOPY FT5500 manufactured by Ricoh Company. (E) -1 Toner fixability test When the mending tape (manufactured by 3M) is applied to the solid printing portion copied by the above copying machine and then peeled off, the ratio of the image density after peeling to the image density before peeling is compared. The ratio (image density after peeling / image density before peeling) was evaluated. The image density was measured with a Macbeth ink densitometer. The PPC paper needs to have an image density after peeling / an image density before peeling of 0.8 or more.

(F) Stationary stability test 100 ml of the sizing agent of Example 1 was placed in a test tube having a length of 30 cm and an inner diameter of 2.1 cm, and allowed to stand at room temperature for 2 months.
The height (mm) of the precipitate settled on the bottom was measured. The same test was performed for the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 10.

(G) Mechanical stability test 50 g of the sizing agent of Example 1 was placed in a cup, and the temperature was 25
A Marlon stability test was conducted at a temperature of 20 ° C., a load of 20 Kg, and a rotation speed of 800 rpm for 5 minutes. The formed aggregate was filtered through a 325 mesh wire net, and the amount of the precipitate relative to the total solid content was measured and expressed as a percentage. The same test was performed for the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 10.

(H) Foaming test 380 ml of pulp beaten to 380 ml of Canadian Standard Freeness (mixed pulp having a pulp ratio of hardwood to softwood of 9: 1) was used as a 2.5% slurry, and this was mixed with 10% pulp. % (Absolute dry weight basis) calcium carbonate (manufactured by Okutama Industry Co., Ltd .; TP121S), pulp 1% (absolute dry weight basis) sulfate band, pulp 0.5% (absolute dry weight basis) amphoteric starch (Oji) Made by National; Cat
o3210) and 1% (based on absolute dry weight) of pulp relative to the sizing agent obtained in Example 1 above, and then diluted to a pulp concentration of 0.25% with dilute water having a pH of 8, and placed in a cylindrical container. Was. Thereafter, the diluted pulp slurry was added to a yield improver of 0.01% based on pulp (manufactured by Hymo; NR12ML).
After the addition of S), the pulp slurry was circulated by a pump and dropped from a height of 50 cm into a container, and the pulp slurry was dropped into a container.
The area of the bubbles accumulated on the liquid surface after minutes was expressed as a percentage with respect to the entire liquid surface area. The same test was performed for the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 10.

(1) Redispersibility in water 1 g of the air-dried product of the sizing agent of Example 1 and 50 g of tap water were placed in a sample bottle, and the mixture was gently stirred to observe the re-dispersibility of the air-dried product. The evaluation was performed on a five-point scale, in which 5 was easily dispersed and 1 was not dispersed at all. The same test was performed for the sizing agents of Examples 2 to 12 and Comparative Examples 1 to 10.

Tables 4 to 7 show the results of the above test.

[Table 4]

[0071]

[Table 5]

[0072]

[Table 6]

[0073]

[Table 7]

From the above results, in the sizing agents of Comparative Examples 1 and 2, the copolymers of Comparative Example 1 were the components of water-soluble mercaptans, and those of Comparative Example 2 were the components of poorly water-soluble mercaptans. No sizing agents of Comparative Examples 3 and 4 were used in the copolymers used in Comparative Examples 3 and 4.
Is a water-soluble mercaptan component, Comparative Example 4 has a sparingly water-soluble mercaptan component in excess of 3 mol%, and the copolymer used for the sizing agent of Comparative Example 5 is (Meta) ) More than 90 mol% of acrylamide components and 6 mol% of carboxylic acid group-containing monomers
The copolymer used in the sizing agent of Comparative Example 6 had less than 40 mol% of acrylamide, and the copolymer used in the sizing agent of Comparative Example 7 had a carboxylic acid group-containing monomer component. The copolymer used in the sizing agent of Comparative Example 8 was less than 6 mol% and had no components of water-soluble mercaptans.
%, And the copolymer used for the sizing agent of Comparative Example 9 contains less than 3 mol% of a component of a hydrophobic monomer.
The copolymer used in the sizing agent of Comparative Example 10 contained more than 20 mol% of a hydrophobic monomer component, and each of Comparative Examples 1 to 10 contained the above-described components (a) to (f) and each component. The sizing paper (application example) using the sizing agent of the above-described example is comparative example 1
The sizing paper using any of the sizing agents of Nos. 10 to 10 (Applied Comparative Example) is superior in all of the degree of Stegt sizing, and in particular, Examples 2 to 12 in which the rosin esterified product is used for a part or all of the rosin-based material It can be said that the sizing paper using the sizing agent is at least 50% excellent, and in particular, is at least 5 times and 2 times as excellent, respectively, as compared with the case of the sizing paper of the application comparative example 1 by the hand-making test. In addition, the sizing paper using the sizing agent of any of the examples is practically applicable to ink-jet printing. In particular, the sizing agents of Examples 2 to 12 using a rosin esterified product for part or all of a rosin-based substance are used. Worn sizing paper is particularly good. In addition, the sizing agent of any of Examples is remarkably superior in static stability and mechanical stability, less foaming, good redispersibility in water, and redispersion than any of the sizing agents of Comparative Examples 1 to 10. This is a remarkable difference as compared with that of the comparative example which can be said to be impossible.

[0075]

According to the present invention, a predetermined sizing degree can be obtained without strictly controlling the pH and without increasing the addition ratio, and the cost is not increased. Less foaming and dirt, emulsifying, size effect, low foaming,
It is possible to provide a sizing agent that can satisfy the mechanical stability, storage stability, and the like, and that can obtain paper satisfying the suitability of both PPC paper and inkjet printing paper, and a sizing paper and a sizing method using the same.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-337997 (JP, A) JP-A-6-93595 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21H 11/00-27/42

Claims (7)

(57) [Claims] 1. A rosin emulsion sizing agent for papermaking comprising (A) a rosin-based substance and (B) an emulsifying dispersant in an aqueous dispersion medium, wherein the (B) emulsifying dispersant comprises at least the following (a) to (c ): At least one type belonging to each of
A compound having at least one mercaptan belonging to each of the following (e) and (f) in the copolymer component, and (a) 40 to 90 mol%, (b) 3 to 20 mol%, and (C) 0.2 to 100 mol% of the monomers (a) to (c) consisting of 6 to 40 mol%,
A rosin emulsion sizing agent for papermaking containing an acrylamide copolymer obtained by polymerizing 3 mol% and 0.2 to 3 mol% of the component (f). (A) at least one of acrylamide and methacrylamide (b) hydrophobic monomers (c) monomers containing a carboxylic acid group and / or a salt thereof (e) water-soluble mercaptans (f) hardly water-soluble mercaptans 2. A papermaking rosin emulsion sizing agent containing (A) a rosin-based substance and (B) an emulsifying dispersant in an aqueous dispersion medium, wherein the (B) emulsifying dispersant has at least the following (a) to (d ): At least one type belonging to each of
A compound having at least one mercaptan belonging to each of the following (e) and (f) in the copolymer component, and (a) 40 to 90 mol%, (b) 3 to 20 mol%, (C) 6 to 40 mol% and (d) 0.5 to 5 mol%
An acrylamide-based polymer obtained by polymerizing 0.2 to 3 mol% of the component (e) and 0.2 to 3 mol% of the component (f) with respect to 100 mol% of the monomers (a) to (d) A rosin emulsion sizing agent for papermaking containing a copolymer. (A) at least one of acrylamide and methacrylamide (b) hydrophobic monomers (c) monomers containing carboxylic acid groups and / or salts thereof (d) monomers containing sulfonic acid groups and / or salts thereof (E) Water-soluble mercaptans (f) Hardly water-soluble mercaptans 3. The rosin emulsion sizing agent for papermaking according to claim 1, wherein the component (c) is a carboxylic acid group-containing monomer, and the carboxylic acid group-containing monomer is a dibasic carboxylic acid monomer. . 4. The water-soluble mercaptan (e) has 2 carbon atoms.
Or 3 mercaptans, and mercaptoethanol, cysteamine hydrochloride, mercaptopropionic acid,
At least one selected from the group consisting of mercaptopropionate, thioglycolic acid, thioglycolate, thioacetic acid, and thioacetate, and (f) a water-insoluble mercaptan having 4 to 18 carbon atoms The rosin emulsion sizing agent for papermaking according to any one of claims 1 to 3, which is at least one of the following. (A) The rosin-based substance is at least one kind of at least one of rosin esters and fortified rosin esters, or at least one of at least one kind of rosin and fortified rosin. , At least one mixture of at least one of rosin esters and fortified rosin esters, and at least one of at least one of the rosin esters and fortified rosin esters is more than 10% by weight of the rosin-based material. The rosin emulsion sizing agent for papermaking according to any one of claims 1 to 4, which is not a small amount. 6. A sizing paper sized using the rosin emulsion sizing agent for papermaking according to any one of claims 1 to 5. 7. A sizing method for obtaining sized paper by having a step of adding the rosin emulsion sizing agent for papermaking according to any one of claims 1 to 5 to a pulp slurry having a pH of 5.0 to 9.0.