JPH11286889A - Rosin-based emulsion sizing agent for papermaking and paper sizing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rosin-based emulsion sizing agent for papermaking good in mechanical stability, scarcely producing flocculates and excellent in sizing properties especially in a neutral region by mixing a rosin substance with a specific dispersing agent and water. SOLUTION: This rosin-based emulsion sizing agent for papermaking is obtained by compounding 20-90 wt.% of a (fortified) rosin and/or a (fortified) rosin ester with a dispersing agent comprising an acrylamide- or a methacrylamide-based copolymer containing 50-90 mol.% of (meth)acrylamide, 1-40 mol.% of istaconic acid (salt), 0.5-10 mol.% of a sulfone group-containing monomer such as styrenesulfonic acid (salt) or a phosphoric acid (salt)-containing monomer such as acid phosphoxyethylene (meth)acrylate, 5-25 mol.% of a hydrophobic monomer such as an acrylic or a methacrylic ester and <=20 mol.% of a hydrophilic monomer except the (meth)acrylamide and a hydrophobic substance such as a petroleum resin prepared by polymerizing a 5C or a 9C fraction as a dispersed phase of the emulsion in an amount of <=45 pts.wt. based on 100 pts.wt. of the rosin substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rosin emulsion sizing agent for papermaking and a method for sizing paper.

[0002]

2. Description of the Related Art In recent years, sizing agents for papermaking have been mainly used due to the demand for closed papermaking systems and the like. Also, in consideration of the adverse effects such as deterioration of a paper machine due to acidic papermaking, a rosin-based emulsion-type sizing agent that is excellent in sizing properties in a neutral region is required. In addition, as a dispersant used in the emulsion type sizing agent, a cationized starch or a cationic polymer is usually used as a fixing agent for the sizing agent. Therefore, an anionic dispersant is used from the viewpoint of fixability. I have.

As such dispersants, for example, low molecular weight surfactants such as sodium alkyl sulfate, sodium alkylbenzene sulfonate, and sulfate of polyoxyethylene alkyl phenyl ether are known. However, since low-molecular-weight surfactants cause large foaming during papermaking, polymer-based dispersants with low foaming have recently been used.

As a polymer dispersant, for example, Japanese Patent Application Laid-Open No. 1-203331 discloses a dispersant having low foaming property such as a hydrophobic monomer such as styrene and a hydrophilic monomer such as acrylic acid and sulfonic acid. Anionic copolymers having as a main component have been proposed. But,
When the proportion of the acrylic acid-based hydrophilic monomer is large, the copolymer is insolubilized by interaction with a cationic substance such as calcium present in the papermaking system, and as a result, the emulsion is destroyed. Therefore, aggregates are generated and cause machine trouble. Also, when the proportion of the sulfonic acid-based monomer, which is a strong acid, increases, the sizing agent disperses stably in hard water, but the cohesive force increases, resulting in uneven distribution of the sizing agent on the paper. Resulting in.

[0005]

DISCLOSURE OF THE INVENTION The present invention has good mechanical stability, has little formation of aggregates due to interaction with a cationic substance such as calcium existing in a papermaking system, and has good hard water stability. It is an object of the present invention to provide a rosin-based emulsion sizing agent for papermaking and a paper sizing method which use a polymer dispersant and have excellent sizing properties, particularly excellent sizing properties in a neutral region and low foaming properties.

[0006]

Means for Solving the Problems The present inventors have intensively studied to solve the above problems. As a result, a specific rosin substance including a rosin ester or the like is used as a rosin substance, and a hydrophilic (meth) acrylamide is used as a main component as a dispersant of the specific rosin substance, and a cationic substance such as calcium is used. By combining itaconic acid, which has less interaction with the substance than acrylic acid, and a copolymer of a specific composition comprising a sulfo (salt) group or a phosphoric acid (salt) group-containing monomer of a strong acid as an essential anionic component, It has been found that the fixation of the sizing agent to the pulp fiber is improved, and a rosin-based emulsion sizing agent for papermaking having excellent sizing properties, particularly sizing properties in a neutral region and low foaming properties, can be obtained. The present invention has been completed based on this new finding.

That is, the present invention relates to an emulsion sizing agent for papermaking comprising a rosin substance, a dispersant and water, wherein the rosin substance comprises (a) rosins or fortified rosin and / or (b) rosin ester. Or (A) 50 to 90 mol% of (meth) acrylamide, (B) itaconic acid and / or
Or a salt thereof 1 to 40 mol% (C) a sulfo (salt) group-containing monomer or a phosphoric acid (salt) group-containing monomer 0.5 to
The present invention relates to a rosin-based emulsion sizing agent for papermaking, which is a (meth) acrylamide-based copolymer containing 10 mol% and (D) 5 to 25 mol% of a hydrophobic monomer. The present invention also relates to a paper sizing method, wherein the rosin emulsion sizing agent for papermaking is used in a pH range of 6 to 8.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The disperse phase of the rosin-based emulsion sizing agent for papermaking of the present invention contains a rosin substance composed of (a) rosin or reinforced rosin and / or (b) rosin ester or rosin ester as a main component. Is formed.

(A) Rosins include gum rosin, wood rosin, tall oil rosin and the like. These rosins may be partially used in combination with hydrogenated rosin, disproportionated rosin, polymerized rosin, aldehyde-modified rosin, and the like.

[0010] The fortified rosin is obtained by modifying a part of the rosins with an α, β-unsaturated carboxylic acid or the like. Therefore, the fortified rosin contains unreacted rosins in addition to the α, β-unsaturated carboxylic acid-modified rosin.
Examples of the α, β-unsaturated carboxylic acid include maleic anhydride, maleic acid, maleic acid monoesters or maleic diesters obtained from lower alcohols and maleic anhydride, fumaric acid, N-alkylmaleimides,
Examples include itaconic acid, itaconic anhydride, acrylic acid and the like. Among these, maleic anhydride, maleic acid,
Maleic acid monoesters, fumaric acid, itaconic acid,
Itaconic anhydride is preferred. The amount of the α, β-unsaturated carboxylic acid to be used is generally 1 mol part or less, preferably about 0.05 to 0.75 mol part, particularly preferably 0.10 to 0.1 mol part, per 1 mol part of rosins. It is about 70 mol parts. The denaturation reaction is usually carried out at a temperature of about
Perform for about 24 hours.

(B) Rosin ester refers to one produced by a known esterification method of a rosin and a polyhydric alcohol. Usually, after charging both, normal pressure, depending on the boiling point of the polyhydric alcohol, under reduced pressure or under pressure, the temperature 150 ~
Dehydration condensation is performed at about 300 ° C. for about 3 to 40 hours with stirring. If necessary, benzene,
Dehydration condensation can be carried out azeotropically using a solvent such as toluene or xylene. Various known alcohols can be used as the polyhydric alcohol, and trihydric or tetrahydric alcohols are preferred. For example, trihydric alcohols include glycerin, trimethylolpropane, trimethylolethane, 3-methylpentane-1,3,5-triol and the like, and tetrahydric alcohols include pentaerythritol and diglycerin. Further, amino alcohols such as triethanolamine and triisopropanolamine can also be used. One or more of these polyhydric alcohols can be used. In addition, the charging ratio of the rosin and the polyhydric alcohol is determined by the equivalent ratio of the hydroxyl group of the polyhydric alcohol to the carboxyl group of the rosin [−OH
(Eq) /-COOH (eq)] is usually 0.1 to 1.
5, preferably in the range of 0.1 to 1.0. In addition to producing a completely esterified product as a rosin ester, it is also possible to produce a rosin ester containing unreacted rosins. When the equivalent ratio is less than 0.1, the ratio of the rosin ester becomes small, and the improvement of the sizing effect in the neutral region of the obtained sizing agent becomes insufficient. The equivalent ratio is 1.
If it exceeds 5, a large amount of free hydroxyl groups remain in the resulting rosin ester, and when used as a sizing agent, the sizing effect is undesirably reduced due to the remaining hydroxyl groups.

[0012] The reinforced rosin ester is obtained by reacting a rosin with a polyhydric alcohol and an α, β-unsaturated carboxylic acid or the like sequentially or simultaneously. Sequentially, a rosin may be reacted with a polyhydric alcohol followed by an α, β-unsaturated carboxylic acid or the like,
It means that polyhydric alcohol may be reacted after rosins are reacted with α, β-unsaturated carboxylic acid or the like.
The esterification reaction with a polyhydric alcohol and the modification reaction with an α, β-unsaturated carboxylic acid or the like may be performed in the same manner as described above.

The rosin substance of the present invention contains the above-mentioned (b) rosin ester or fortified rosin ester, and particularly contains (a) rosin or fortified rosin and (b) rosin ester or fortified rosin ester in combination. Size effect in the active region can be improved.
Therefore, the content of the (b) rosin ester or the fortified rosin ester in the rosin substance is preferably 20 to 90% by weight. When the proportion of (b) is less than 20% by weight, the size effect in the neutral region is not sufficiently improved, and when the proportion of (b) exceeds 90% by weight, the size effect tends to lose its characteristics. There is.

In the rosin substance of the present invention, (a)
When (b) and (b) are used together, (a) and (b) can be prepared by separately preparing and then mixing these, and in addition, the reaction product obtained as a result of (b) can be obtained. If it contains the above (a) and (b), the reaction product can be used as it is.
For example, as a result of producing a rosin ester as (b), if the reaction product contains a predetermined amount of unreacted rosins in addition to the rosin ester, the reaction product is converted into (a) and (b) of the present invention. It can be used as a rosin substance consisting of (b).

In the present invention, as long as the above-mentioned predetermined rosin substance is used, it can be used as it is as the dispersed phase of the emulsion. As long as the effects of the present invention are not impaired, petroleum resins obtained by polymerizing the C5 fraction or the C9 fraction, olefin oligomers having 12 to 18 carbon atoms, rosin metal soap, phenol resin-modified reinforced rosin, terpene-based resins, At least one hydrophobic substance selected from the group consisting of maleated petroleum resin, maleated olefin oligomer, paraffin wax, AKD, and ASA is used in an amount of 45 parts by weight or less, preferably 25 parts by weight, based on 100 parts by weight of the rosin substance. Up to parts by weight can be added to the dispersed phase.

In the present invention, (A) (meth) acrylamide 50 to 90 is used as a dispersant for the predetermined rosin substance.
Mol%, (B) itaconic acid and / or a salt thereof 1
(Meth) acrylamide containing (C) 0.5 to 10 mol% of a monomer having a sulfo (salt) group or phosphoric acid (salt) group and 5 to 25 mol% of a (D) hydrophobic monomer A system copolymer is used.

(A) (Meth) acrylamide means acrylamide and / or methacrylamide (hereinafter, (meth) has the same meaning). (A)
(Meth) acrylamide is used to impart hydrophilicity to the dispersant, and the amount of the (meth) acrylamide used is (meth)
It is 50 to 90 mol%, preferably 50 to 70 mol%, of the total mol of the monomers constituting the acrylamide copolymer. If it exceeds 70 mol%, it becomes difficult to make the emulsion particles fine, and if it exceeds 90 mol%, emulsification cannot be achieved.

(B) In order to maintain emulsifiability, itaconic acid is used in an amount of 1 to 40 mol% of the total mol of the monomers constituting the (meth) acrylamide copolymer, and the lower limit is preferably 5 mol. %, And the upper limit is preferably in the range of 30 mol%. If the amount of (B) itaconic acid exceeds 40 mol%, the polymerization rate is reduced and the emulsifying power is also weakened, which is not preferred.

(C) a sulfo (salt) group or phosphoric acid (salt)
The group-containing monomer is used to impart a strong anionic property to the dispersant, and the amount of the group-containing monomer used is (meth)
It is 0.5 to 10 mol% of the total molar sum of the monomers constituting the acrylamide copolymer, the lower limit is preferably 1 mol%, and the upper limit is preferably 5 mol%. The carboxyl group-containing monomer, which is a weak acid, is compared with the sulfo (salt) group or phosphoric acid (salt) group-containing monomer.
The use of acrylic acid instead does not improve the hard water dilution stability. That is, in the present invention, as the anionic component of the dispersant, a relatively acidic sulfo (salt) is used.
The use of a carboxyl group or a phosphoric acid (salt) group-containing monomer improves poor emulsion stability due to hard water dilution when a carboxyl group is used. (C)
When the amount of the component is less than 0.5 mol%, the fixing of the sizing agent tends to decrease due to a decrease in anionicity. Distribution tends to be non-uniform and the size effect tends to decrease.

Examples of the sulfo (salt) group-containing monomer include styrene sulfonic acid (salt), vinyl sulfonic acid (salt), 2- (meth) acrylamido-2-methylpropane sulfonic acid (salt), (meth) acrylic Acid sulfoethyl (salt), sulfopropyl (meth) acrylate (salt),
Sulfonic acid (salt) such as (meth) allylsulfonic acid (salt)
Sulfate (salt) of hydroxyethyl (meth) acrylate, sulfate (salt) of hydroxypropyl (meth) acrylate, sulfate (salt) of polyoxyalkylene (meth) acrylate, polyoxy Sulfuric acid ester-based monomers such as a sulfuric acid ester (salt) of ethylene alkyl propenyl ether.

Examples of the phosphoric acid (salt) group-containing monomer include acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, and acid phosphooxypolyethylene glycol (meth) acrylate. The (salt) means that the sulfo group or the phosphate group may form a salt such as an alkali metal salt such as a sodium salt or a potassium salt or an ammonium salt. Hereinafter, (salt) has the same meaning. These sulfo (salt) group-containing monomers or phosphoric acid (salt) group-containing monomers can be used alone or in combination of two or more.

The (D) hydrophobic monomer is used for imparting hydrophobicity to the dispersant, and the amount of the (D) hydrophobic monomer depends on the amount of the monomer constituting the (meth) acrylamide copolymer as the dispersant. The total molar sum is 1 to 20 mol%, the lower limit is preferably 5 mol%, and the upper limit is preferably 15 mol%. When the amount is less than 1 mol% or more than 20 mol%, emulsification becomes extremely difficult, and any case is not preferable.

(D) As the hydrophobic monomer, (meth)
Alkyl groups such as ethyl acrylate, methyl (meth) acrylate and butyl (meth) acrylate, and alkane groups such as cyclohexyl (meth) acrylate having 1 to 20 carbon atoms (meth) acrylate, styrene, α- Styrenes such as methyl styrene, styrene monomers of styrene compounds having an alkyl group having 1 to 4 carbon atoms in the aromatic ring of these styrenes, carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate, carbon number 6 to 22 α-olefins, alkyl vinyl ethers having 1 to 22 carbon atoms,
Examples thereof include vinylpyrrolidone. Of these,
In particular, (meth) acrylates, styrene monomers,
Vinyl carboxylate is preferred in view of emulsifiability.

Further, the dispersant of the present invention may contain (E) (A) (meth) acrylamide in a range of not more than 20 mol% of the total mol of the monomers constituting the (meth) acrylamide copolymer. A hydrophilic monomer except for can be used. Examples of such hydrophilic monomers include nitrile monomers such as (meth) acrylonitrile; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, glycerin mono (meth) acrylate; (Meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol (meth) acrylate,
Hydroxyl group-containing monomers such as (meth) allyl alcohol; polyoxyalkylene (meth) acrylate, polyoxyalkylene glycerin (meth) acrylate, polyoxyalkylene monoalkyl (meth) acrylate, polyoxyalkylene (meth) ) Polyoxyalkylene group-containing monomers such as allyl ether and polyoxyalkylene glycerin (meth) allyl ether.

As a method for producing the copolymer as the dispersant of the present invention, various known methods such as solution polymerization, emulsion polymerization, suspension polymerization and the like can be adopted, and the copolymer can be easily obtained by copolymerizing the above-mentioned monomers. Can. In the case of solution polymerization, solvents such as isopropyl alcohol, ethyl alcohol, and methyl isobutyl ketone can be used. The emulsifier used in the emulsion polymerization method is not particularly limited, and various surfactants can be used. Examples of the anionic surfactant include dialkyl sulfosuccinate, alkane sulfonate, α-
Olefin sulfonate, polyoxyethylene alkyl ether sulfosuccinate, polyoxyethylene styrylphenyl ether sulfosuccinate, naphthalenesulfonic acid formalin condensate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkylphenyl ether sulfate Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitan fatty acid ester, and a reaction in which a vinyl group, an allyl group, or a propenyl group is introduced into these surfactants. Surfactants and the like. One or more of these surfactants can be appropriately selected and used, and the amount of the surfactant is usually about 0.1 to 10% by weight based on all charged monomers. The polymerization initiator used in the polymerization is not particularly limited, and various types such as persulfates, peroxides, azo compounds, and redox initiators can be used. Chain transfer agents isopropyl alcohol, carbon tetrachloride, ethylbenzene, isopropylbenzene, cumene, thioglycolate, alkyl mercaptan, 2,4-diphenyl-4-methyl-
1-pentene or the like can be used as appropriate.

The molecular weight of the resulting copolymer as a dispersant is
The weight average molecular weight is usually from 1,000 to 200,000, preferably from 1,000 to 100,000, since it directly correlates with the dispersibility of the rosin substance (reaction product). If it is less than 1000, the mechanical stability of the emulsion becomes poor,
If it exceeds 0, the product viscosity will be high. The copolymer is usually water-soluble, but may be dispersible.

The emulsion sizing agent for papermaking of the present invention comprises:
Using the rosin substance obtained as described above and a copolymer as a dispersant, for example, JP-B-53-4866 (melting high-pressure emulsification), JP-B-53-22090 (solvent high-pressure emulsification) or It can be produced by a known method such as Japanese Patent Publication No. 52-77206 and Japanese Patent Publication No. 58-4938 (inversion emulsification method).

For example, in the case of the solvent high-pressure emulsification method, the above-mentioned copolymer as a dispersant and water, and, if necessary, sodium hydroxide, hydroxide, etc., for a rosin substance previously dissolved in an organic solvent insoluble in water. Add alkali substances such as potassium, ammonia and lower amine, emulsify through homogenizer, piston type high pressure emulsifier, ultrasonic emulsifier, etc.,
Next, the organic solvent is distilled off. The timing of adding the copolymer is not particularly limited, and when emulsification is performed using a small amount of an alkali or a surfactant, even after passing through an emulsifier, or even after distilling off the solvent, there is no problem. A good aqueous emulsion can be obtained.

In the case of the inversion method, the rosin material is heated and stirred usually at 90 to 160 ° C. to prepare a molten rosin material. Then, while stirring the molten rosin substance, an aqueous solution of the copolymer or the aqueous emulsion and a predetermined amount of hot water are added thereto to invert the phase, and the emulsion in which the rosin substance is a dispersed phase and water is a continuous phase. Is formed.

In the above solvent high-pressure emulsification and inversion emulsification,
The copolymer serving as a dispersant is usually 1 to 30% by weight, preferably 2% by weight as a lower limit, and preferably 20% by weight as an upper limit, based on the whole dispersed phase containing a rosin substance.
Range. If it is less than 1% by weight, the dispersing power is not sufficient,
It is not economical to use more than 30% by weight. If desired, these emulsions obtained can be diluted with water or alkaline water to adjust the pH of the emulsion.

In the above solvent high-pressure emulsification and reversal emulsification, a surfactant may be added to the copolymer in such an amount that the foaming property and the size effect are not adversely affected. Examples of the surfactant include various surfactants used at the time of emulsion polymerization of the copolymer.

The obtained rosin emulsion sizing agent of the present invention usually has a solid content of 10 to 70% by weight, preferably 30% by weight as a lower limit, and preferably 55% by weight as an upper limit. It is an aqueous emulsion uniformly dispersed as particles having a size of 1 μm or less, which has a milky appearance and usually has a pH of 2.0 to 7.5. The aqueous emulsion is stable at room temperature for at least 6 months and does not precipitate. In addition, since it has excellent dilution stability in hard water, it can be sufficiently diluted even when using water from rivers, tap water, wells, etc., and is well dispersed in an aqueous dispersion of pulp. And it is also extremely low foaming. Further, as shown in Examples described later, the mechanical stability is good.

The paper-making emulsion sizing agent obtained by the present invention may be added to, for example, an aqueous dispersion of pulp together with a fixing agent such as aluminum sulfate and then sized at pH 4 to 8, or may be added to an aqueous dispersion of pulp. A method of adding paper together with a fixing agent and the like to form a paper at a pH of 4 to 8 can be adopted, and an excellent size effect can be imparted to the paper in a wide range of paper making pH. Especially neutral range (pH 6-8)
Excellent size effect. When fillers are used, silicates such as talc, clay and kaolin, inorganic fillers such as titanium dioxide and calcium carbonate, and organic fillers such as urea-formalin can be used alone or in combination of two or more. In this case, the papermaking emulsion sizing agent is usually used in an amount of about 0.05 to 3% by weight (based on dry weight) based on pulp. Further, since the sizing agent of the present invention is excellent in fixability to pulp, the amount of aluminum sulfate used can be reduced. Further, even in high-temperature papermaking, the size effect does not decrease even if the hardness of the water becomes high, or even if contaminants increase due to the closed use of used paper or the like.

[0034]

The rosin emulsion sizing agent for papermaking of the present invention has good sizing effects, especially in the neutral region. Further, it has good mechanical stability and stability in dilution with hard water, and can sufficiently cope with recent closed papermaking systems. Moreover, because of low foaming property, workability during papermaking is good.

[0035]

The rosin-based emulsion sizing agent for papermaking of the present invention will be described more specifically with reference to examples and comparative examples. Reference Examples are a production example of a rosin substance used in the present invention and a production example of an acrylamide-based copolymer as a dispersant. In each example, parts and% are by weight unless otherwise specified.

Reference Example 1 (Production Example of Enriched Rosin) 100 parts of gum rosin having an acid value of 170 was charged into a 1-liter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a water separator, and a cooler. After heating to 160 ° C., 8 parts of fumaric acid was added, and the mixture was heated and kept at 210 ° C. for 3 hours. The obtained reaction product had a softening point of 117 ° C. and an acid value of 242.

Reference Example 2 (Production Example of Rosin Ester) In the same reactor as in Reference Example 1, 100 parts of gum rosin having an acid value of 170 and 9.3 parts of glycerin (charge equivalent ratio (-OH /
-COOH) = 1.00), and 25
The mixture was heated to 0 ° C. and esterified at the same temperature for 8 hours to obtain a rosin ester having a softening point of 84 ° C. and an acid value of 6.

Reference Example 3 (Production Example of Enhanced Rosin Ester) After heating the rosin ester obtained in Reference Example 2 to 160 ° C., 8.2 parts of maleic anhydride was added, and the mixture was heated and kept at 210 ° C. for 2 hours to soften. A reaction product containing a strengthened rosin ester having a point of 102 ° C. and an acid value of 183 was obtained.

Reference Example 4 (Production Example of Rosin Ester) In Reference Example 2, except that 9.3 parts of glycerin was used and 10.3 parts of pentaerythritol (charge equivalent ratio = 1.00) was used. Softening point 105
A rosin ester having an acid value of 15 and an acid value of 15 was obtained.

Reference Example 5 (Production Example of Rosin Ester) In Reference Example 2, except that the amount of glycerin used was changed to 6 parts (charge equivalent ratio (-OH / -COOH) = 0.65). In the same manner as in the above, a rosin ester having a softening point of 85 ° C. and an acid value of 59 was obtained.

Reference Example 6 (Production Example of Dispersant) A reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooler was charged with 57.7 parts of acrylamide (73 mol% of the total mol of monomers; The same), 21.7 parts of itaconic acid (15
Mol%), 9.2 parts (4 mol%) of 2-acrylamido-2-methylpropanesulfonic acid, 11.4 parts (8 mol%) of n-butyl acrylate, 5 parts of lauryl mercaptan,
5 parts of sodium salt of polyoxyethylene (n = 13) dodecylphenyl ether sulfate, 2 parts of polyoxyethylene (n = 9) oleyl ether, 5 parts of ammonium persulfate and 400 parts of ion-exchanged water are mixed and heated,
The reaction was carried out at 80 ° C. for 5 hours to obtain an aqueous solution of a copolymer. Thereafter, the mixture was cooled, 2-acrylamido-2-methylpropanesulfonic acid and an equimolar amount of sodium hydroxide were added at 60 ° C., and the mixture was stirred for 1 hour to give a concentration of 15% and a weight average molecular weight of 40.
An aqueous solution of 000 copolymer was obtained.

Reference Example 7 (Production Example of Dispersant) In Reference Example 6, except that 2-acrylamido-2-methylpropanesulfonic acid was replaced with the same mole% of ammonium propyl methacrylate ammonium salt, The reaction was carried out in the same manner as in Reference Example 6, and the concentration was 15%.
An aqueous solution of a copolymer having a weight average molecular weight of 20,000 was obtained.

Reference Example 8 (Production Example of Dispersant) In Reference Example 6, 52.3 parts (70 mol%) of acrylamide, 26.0 parts (19 mol%) of itaconic acid, and methacrylic acid were used as unsaturated monomers. The reaction was carried out in the same manner as in Reference Example 6 except that 10.1 parts (4 mol%) of ammonium salt of hydroxypropyl sulfate and 11.6 parts (6 mol%) of 2-ethylhexyl acrylate were used. %, An aqueous solution of a copolymer having a weight average molecular weight of 30,000 was obtained.

Reference Example 9 (Production Example of Dispersant) In Reference Example 6, 57.4 parts (70 mol%) of acrylamide and 7.1 parts (3 mol%) of sodium styrenesulfonate were used as unsaturated monomers. The reaction was carried out in the same manner as in Reference Example 6 except that 20.4 parts (17 mol%) of styrene and 15 parts (10 mol%) of itaconic acid were used.
%, An aqueous solution of a copolymer having a weight average molecular weight of 30,000 was obtained.

Reference Example 10 (Production Example of Dispersant) In a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooler, 300 parts of ion-exchanged water and polyoxyethylene (n = 13) dodecyl phenyl ether sulfate were added. Of sodium salt, and stirred under a nitrogen gas atmosphere. Thereafter, 44.3 parts (63 mol%) of acrylamide, 13.7 parts (8 mol%) of allylsulfonic acid sodium salt, 28.3 parts (22 mol%) of itaconic acid, and 13.7 parts of 2-ethylhexyl methacrylate ( 7 mol%) and 5 parts of lauryl mercaptan and potassium persulfate 3
Aqueous solution obtained by dissolving 50 parts in 50 parts of ion-exchanged water separately.
The reaction was carried out dropwise at 3 ° C. over 3 hours, and a half molar amount of sodium hydroxide of itaconic acid was added to give a concentration of 20%.
An aqueous solution of a copolymer having a weight average molecular weight of 35,000 was obtained.

Reference Example 11 (Production Example of Dispersant) In a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooler, 230 parts of ethyl alcohol and acrylamide 5 were added.
1.1 parts (75 mol%), 20.0 parts of itaconic acid (16
Mol%), ammonium salt of polyoxyethylene alkylpropenyl ether sulfate (trade name “AQUALON HS-10” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 22.9
Parts (3 mol%) and 6 parts (6 mol%) of styrene.
The mixture was stirred under a nitrogen gas atmosphere. Thereafter, 3 parts of azobisisobutyronitrile was added as a polymerization initiator, the temperature was raised to 80 ° C., the temperature was maintained for 4 hours, 1 part of azobisisobutyronitrile was further added, and the temperature was maintained for 3 hours. 150 parts of exchanged water was added to distill off ethyl alcohol.
After completion of the distillation, the mixture was cooled, itaconic acid and an equimolar amount of potassium hydroxide were added at 60 ° C., and the mixture was stirred for 1 hour to obtain an aqueous solution of a copolymer having a concentration of 20% and a weight average molecular weight of 60000.

Reference Example 12 (Production Example of Dispersant) A reaction was carried out in the same manner as in Reference Example 11 except that vinyl acetate was used in the same mol% in place of styrene. An aqueous solution of a copolymer having an average molecular weight of 45,000 was obtained.

Reference Example 13 (Production Example of Comparative Dispersant) In Reference Example 6, 21.9 parts (35 mol%) of acrylamide, 18.2 parts (10 mol%) of 2-acrylamido-2-methylpropanesulfonic acid, Itaconic acid 34.3
% (30 mol%), 3.1 parts of acrylic acid (5 mol%),
And the reaction was carried out in the same manner as in Reference Example 6 except that n-butyl acrylate and 22.5 parts (20 mol%) were used.
%, An aqueous solution of a copolymer having a weight average molecular weight of 20,000 was obtained.

Reference Example 14 (Production Example of Comparative Dispersant) In Reference Example 6, as an unsaturated monomer, 26.1 parts (40 mol%) of methacrylamide, 59.8 parts (50 mol%) of itaconic acid, Sodium styrenesulfonate 9.5
Part (5 mol%) and 4.6 parts (5 mol%) of methyl methacrylate.
The reaction was carried out in the same manner as in Reference Example 6 except that (mol%) was used. Thereafter, the mixture was cooled and had a concentration of 15% and a weight average molecular weight of 1
A dispersion of 5000 copolymers was obtained.

Reference Example 15 (Production Example of Comparative Dispersant) In Reference Example 6, 30.8 parts (35 mol%) of acrylamide and 7.6 parts (3 mol%) of sodium styrenesulfonate were used as unsaturated monomers. ), 12.9 parts (10 mol%) of styrene, 8.7 parts (7 mol%) of methyl methacrylate, and 40.1 parts (45 mol%) of acrylic acid, in the same manner as in Reference Example 6. The reaction was performed. afterwards,
After cooling, at 60 ° C., an equimolar amount of potassium hydroxide was added to acrylic acid, and the mixture was stirred for 1 hour.
An aqueous solution of 0000 was obtained.

Reference Example 16 (Production Example of Comparative Dispersant) In a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooler, 150 parts of isopropyl alcohol, 100 parts of ion-exchanged water, 27.4 parts of styrene (40 parts) Mol%), itaconic acid 21.5 parts (25 mol%), methyl methacrylate 6.6 parts (10 mol%) sodium styrene sulfonate 2
7.2 parts (20 mol%), and 17.3 parts (5 mol%) of a polyethylene oxide methacrylate adduct (n = 10),
2 parts of lauryl mercaptan was added, and the mixture was stirred under a nitrogen gas atmosphere. Thereafter, the mixture was heated to 60 ° C., 5 parts of ammonium persulfate was added, the temperature was raised to 80 ° C., and the temperature was maintained for 3 hours. Then, 200 parts of ion-exchanged water was added, and isopropyl alcohol was distilled off. After isopropyl alcohol was distilled off, sodium hydroxide and 300 parts of ion-exchanged water, which were half the molar amount of itaconic acid, were added and stirred for 1 hour to obtain an aqueous solution of a copolymer having a concentration of 20% and a weight average molecular weight of 100,000.

Example 1 (Production of emulsion sizing agent) 70 parts of the fortified rosin obtained in Reference Example 1 and 30 parts of the rosin ester obtained in Reference Example 2 were dissolved in 200 parts of toluene. 60 parts of an aqueous solution of the obtained copolymer (dispersant) and 300 parts of hot water (70 ° C.) were mixed and emulsified by using a high-pressure emulsifier.
A 5% emulsion size was prepared.

Examples 2 to 4 and Comparative Examples 1 to 5 In the same manner as in Example 1, except that the type of the rosin substance or the copolymer (dispersant) was changed as shown in Table 1, An emulsion size was prepared.

Example 5 70 parts of the reinforced rosin obtained in Reference Example 1 and 30 parts of the rosin ester obtained in Reference Example 4 were heated and melted at 160 ° C.
While stirring, 150 parts of the copolymer obtained in Reference Example 10 was added over 1 hour. Hot water is gradually added to the water-in-oil emulsion thus obtained while stirring to invert the phase to form an oil-in-water emulsion.
A 5% emulsion size was prepared.

Examples 6 and 7 and Comparative Example 6 The emulsion size was changed in the same manner as in Example 5 except that the type of the rosin substance or the copolymer (dispersant) was changed as shown in Table 1. An agent was prepared.

[0056]

[Table 1]

The mechanical stability, hard water dilution stability and cohesion of the emulsion sizing agents obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were measured by the following methods. Table 2 shows the results.

(1) Mechanical stability 50 g of an emulsion sizing agent was weighed and placed in a container of a Marlon-type stability tester (manufactured by Shinsei Sangyo Co., Ltd.) at a temperature of 25 ° C., a load of 10 kg, and a rotation speed of 1000 rpm. p. m. After adding a mechanical shear for 5 minutes, the formed aggregate was filtered off with a 200 mesh wire mesh, and the mechanical stability was calculated according to the following equation.

Mechanical stability (%) = (absolute dry weight of aggregate / absolute dry weight of sample emulsion) × 100

(2) Hard water dilution stability 5% of emulsion sizing agent in hard water having a hardness of 100 ° DH
And the state of dispersion was observed. The evaluation was based on ○: dispersed, Δ: partially aggregated, ×: aggregated.

(3) Coagulability Sulfuric acid band and cationized starch (Oji Ace K-100, manufactured by Oji Cornstarch Co., Ltd.) were added to tap water kept at 40 ° C. at concentrations of 0.01% and 0.005%, respectively. So that the emulsion size is 0.01%
After addition, it diffused uniformly. The pH at this time was 4. This solution was adjusted to pH 7 with sodium hydroxide,
After stirring for minutes, the aggregation state of the emulsion was observed.
The evaluation was based on ○: dispersed, Δ: partially aggregated, ×: aggregated.

[0062]

[Table 2]

When the emulsion sizing agents obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were used as sizing agents for papermaking in Practical Test 1, Practical Test 2 and Practical Test 3, the sizing degree of the formed paper was (Seconds) using the Stekicht method (JIS
P 8122). Table 3 shows the results.

Practical test 1 400ml Canadian Standard Freeness
Pulp beaten with (L-BKP / N-BKP = 2/1)
Into a 2% aqueous slurry and kept at 40 ° C. Then
Add 10% (based on absolute dry weight) carbonated carbon dioxide to pulp
Lucium, 1.0% (based on absolute dry weight) sulphate bath based on pulp
And cationization of pulp to 0.5% (on a dry basis)
Starch (Oji Ace K-100, Oji Cornstarch)
And Pulp 0.2% or 0.5% (absolutely dry)
(By weight) emulsion sizing agent was added sequentially
Later, the slurry was diluted to 1%. Pulp slurry
Had a pH of 7.5. After evenly dispersing, tap
Basis weight 60 using PI standard sheet machine
± 1g / m^Two The paper was made so that 5 kg / c
m ^Two Dewater for 5 minutes under the pressure of
After drying at 100 ° C. for 1 minute, the stock was further dried at 20 ° C.
65% R. H. After conditioning for 24 hours under the conditions of
(Seconds) was measured.

Practical Test 2 Pulp having a beating degree of 300 ml (newspaper, containing 3% calcium carbonate) was made into a 2% aqueous slurry and kept at 50 ° C. To this was added a sulfuric acid band of 1.0% based on pulp (based on absolute dry weight), and then an emulsion sizing agent based on 0.3% based on pulp (based on absolute dry weight). Then, the slurry was diluted to 1%, and the pH of the uniformly dispersed slurry was
Was 7.5. Paper was made in the same manner as in Practical Test 1, and the size (seconds) was measured.

[0066]

[Table 3]

Claims (7)

[Claims] 1. A papermaking emulsion sizing agent comprising a rosin substance, a dispersant and water, wherein the rosin substance is (a) rosin or reinforced rosin and / or (b) rosin ester or rosin ester. And the dispersant is (A) (meth) acrylamide 50 to
90 mol%, (B) 1-40 mol% of itaconic acid and / or a salt thereof (C) 0.5-10 mol% of a monomer having a sulfo (salt) group or a monomer having a phosphoric acid (salt) group and (D) hydrophobicity A rosin-based emulsion sizing agent for papermaking, which is a (meth) acrylamide-based copolymer containing 5 to 25 mol% of a reactive monomer. 2. A petroleum resin obtained by polymerizing a C5 fraction or a C9 fraction as an emulsion disperse phase of the papermaking emulsion sizing agent, an olefin oligomer having 12 to 18 carbon atoms, a rosin metal soap, and a phenol resin. Modified reinforced rosin, terpene resin, maleated petroleum resin, maleated olefin oligomer, paraffin wax, AK
The rosin-based emulsion sizing agent for papermaking according to claim 1, wherein the rosin-based emulsion sizing agent for papermaking contains at least 45 parts by weight of at least one hydrophobic substance selected from the group consisting of D and ASA with respect to 100 parts by weight of the rosin substance. 3. A monomer constituting a (meth) acrylamide copolymer as a dispersant, further comprising (E) (A)
3. The rosin-based emulsion sizing agent for papermaking according to claim 1, comprising 20 mol% or less of a hydrophilic monomer excluding (meth) acrylamide. 4. The paper-making rosin-based emulsion sizing agent according to claim 1, wherein the weight average molecular weight of the (meth) acrylamide-based copolymer as the dispersant is from 1,000 to 200,000. 5. The rosin-based emulsion sizing agent for papermaking according to claim 1, wherein the rosin substance contains (b) a rosin ester or a fortified rosin ester in an amount of 20 to 90% by weight. 6. The dispersant according to claim 1, wherein the content of the dispersant is 1 to 30 parts by weight in terms of the solid content of the entire dispersed phase containing the rosin substance.
The rosin emulsion sizing agent for papermaking according to any one of claims 1 to 5. 7. A paper sizing method comprising using the rosin-based emulsion sizing agent for papermaking according to claim 1 in a pH range of 6 to 8.