JP3041622B2 - Paper sizing method and paper obtained by sizing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has an excellent size effect, a good disintegration of waste paper,
The present invention relates to a sizing method for papermaking having little influence on a fluorescent dye and a paper obtained by the sizing method.

[Conventional technology]

2. Description of the Related Art Conventionally, sizing has been performed in ordinary paper and paperboard papermaking methods in order to impart functions such as sizing, waterproofness, and water resistance to these papers. As the sizing method, a sizing agent is added to a stock before forming a paper layer or a sizing agent is applied after forming a paper layer in a papermaking process of paper or paperboard.

In recent years, neutral sizing agents have been used for the purpose of using inexpensive waste paper or waste paper containing inexpensive calcium carbonate as a filler, closing papermaking water, imparting permanent storage properties of paper, etc.
Sizing in the neutral or weakly alkaline range of 5-9,
A so-called neutral sizing method has attracted attention.

As a neutral sizing agent, a sizing agent that exhibits sizing properties by reacting with hydroxyl groups of cellulose of paper stock, for example, an alkyl ketene dimer sizing agent, a reactive sizing agent represented by an alkenyl succinic anhydride sizing agent, a cation Self-fixing type, which has sizing properties and exhibits sizing properties by fixing to paper cellulose, for example, a styrene-dimethylaminoethyl (meth) acrylate-epihalohydrin resin-based sizing agent (hereinafter abbreviated as SDE) Agents. At present, among these neutral sizing agents, alkyl ketene dimer-based sizes are most commonly used.

[Problems to be solved by the invention]

However, when an alkyl ketene dimer-based sizing agent is used, there is an advantage that an excellent sizing effect can be obtained, but it takes time until the sizing effect is expressed, not only the so-called sizing degree rises slowly, but also When the addition ratio is increased, there is a problem that the paper becomes slippery, and there is a problem that the paper adheres to a press roll or a smoother roll of a paper machine at the time of paper making and stains them.

In addition, when SDE is used alone, a good sizing effect cannot be obtained as much as the alkyl ketene dimer sizing agent, and it is difficult to improve the sizing degree even if the addition ratio is increased.
It is not appropriate to use it alone. Not only that, SDE
Has cationized the resin with epihalohydrin,
In the recovery of damaged paper, the fibers of the damaged paper are unraveled, so-called disintegration is poor, and when a fluorescent dye having an effect of improving the whiteness of paper is added, the cationicity of the resin is too strong. There is also a problem that the fluorescence intensity is reduced.

Therefore, a sizing method using an alkylketene dimer-based sizing agent and SDE in combination is also known (JP-A-55-13).
2789, JP-A-57-112497). By using these sizing agents in combination, the rise of the sizing degree is improved, and the alkyl ketene dimer sizing agent can be reduced, so that the problems of press roll contamination and slippage of the formed paper can be improved. However, even when these size papers are used in combination, the rise of the sizing degree is still slow, and the sizing degree is still not sufficient. Furthermore, the problem of poor disintegration of waste paper due to the use of SDE and the problem of lowering the fluorescence intensity of the fluorescent dye still remain, and a satisfactory sizing agent has not been obtained even when these sizing agents are used in combination.

An object of the present invention is to provide a sizing method for papermaking, which has a good rise in sizing degree, has an excellent sizing effect, has a good disintegration property of broke, and is hard to lower the fluorescence intensity of a fluorescent dye, and a paper obtained by the sizing method. Is to do.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve the above problems, and as a result, by separately adding a polymerized polymer sizing agent and an alkyl ketendamer sizing agent to a papermaking system,
The inventors have found that the above objects can be achieved, and have completed the present invention.

That is, the present invention provides at least the following general formula (I):
A polymer obtained from a monomer composition having the molecular structural units represented by (II) and (III) and the monomer corresponding to the general formula (I) being 60 to 95 mol% is dispersed in water and contained. Polymerized sizing agent and the following general formula (IV)
And a sizing agent containing a ketene dimer compound represented by the formula (1), which is separately added to a papermaking system to provide a sizing method for papermaking.

General formula (I) (Wherein R ₁ is H or CH ₃ , R ₂ is H or CH ₃ , —CH (CH ₃ )
_2, a lower alkyl group such as -C (CH _{3) 3.} ) General formula (II) (In the formula, R ₃ represents H or CH ₃ , and R ₄ represents an alkyl group having 1 to 22 carbon atoms or an alkenyl group having _{3 to} 22 carbon atoms, a cyclohexyl group, a phenyl group, a benzyl group, or a glycidyl group.) (III) (Wherein, R ₅ is an alkyl group having 1 to 22 carbon atoms, 3 to 22 carbon atoms)
Shows the alkenyl group or a benzyl group, R ₆ is hydrogen or a methyl group, A is an oxygen atom or -CH ₂ NH-, X ^- represents an anion. ) General formula (IV) (In the formula, R ₇ and R ₈ represent the same or different hydrocarbon groups having 6 to 30 carbon atoms.) At this time, the polymer is represented by the above general formulas (I), (II) and (III) It is also preferable to have a molecular structural unit represented by the following general formula (V) in addition to the molecular structural unit represented by the formula (V).

General formula (V) (In the formula, R ₉ represents H or CH _3. ) In the present invention, a polymerized polymer sizing agent and an alkyl ketene dimer sizing agent are separately added and used.

The invention also provides a paper so sized.

The polymer-based polymer sizing agent contains at least a polymer having a molecular structural unit represented by the above general formulas (I), (II), and (III) in water, and this polymer contains only a monomer corresponding to the molecular structural unit. Alternatively, they can be obtained by polymerizing these with other vinyl monomers such as (meth) acrylamide.

Examples of the monomer corresponding to the general formula (I) include styrene, vinyl toluene, α-methylstyrene, and the like. Examples of the monomer corresponding to the general formula (II) include methyl (meth) acrylate and butyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate,
Lauryl (meth) acrylate, stearyl (meth) acrylate and the like can be mentioned, and the above general formula (III)
As N-ethyl-N, N-dimethyl (2)-(meth) acryloyloxyethyl) ammonium bromide, N-benzyl-N, N-dimethyl (2- (meth) acryloyloxyethyl) ammonium Chloride, N-ethyl-N, N-dimethyl (3- (meth) acryloylaminopropyl) ammonium bromide, N-benzyl-N, N-dimethyl (3- (meth) acryloylaminopropyl) ammonium chloride and the like. it can.

 One or more of the above monomers are used.

The method for preparing the monomer represented by the general formula (III) is not particularly limited, but usually, a tertiary monomer represented by the following general formula (III ′) is converted into a suitable quaternizing agent,
For example, a method of quaternizing with an alkyl halide, dialkyl carbonate, alkyl tosylate, alkyl mesylate, dialkyl sulfate, benzyl halide, or the like can be considered.

(In the formula, R ₆ represents H or CH ₅ , an oxygen atom such as A, or —CH ₂ NH—.) The above polymer is prepared by preparing a monomer of the general formula (III) by quaternization, ) And (II) can be obtained by polymerization with the monomer, etc.
May be quaternized with a quaternizing agent during the polymerization of the monomer with the monomers of the general formulas (I) and (II).

The monomers belonging to the above general formula (III ′) include N, N
-Dimethylaminoethyl (meth) acrylate or N, N
-Dimethylaminopropyl (meth) acrylamide and the like, and one or more of these are used.

As a constitutional molar ratio of the monomer corresponding to the molecular structural unit of the above general formula, the monomer of the general formula (I) is 60% to 95%, the size effect is low when it is 50% or less, and it is obtained when it exceeds 95%. The dispersibility of the polymer in water may be reduced. The molar ratio of the monomer of the general formula (II) is 0.5 to 40
%, Preferably 1 to 30%, and if less than 0.5% or more than 40%, the size effect may be reduced. The amount of the monomer of the general formula (III) is 2 to 40%, preferably 5 to 30%. When the amount is less than 2%, the dispersibility of the obtained polymer in water may decrease. May be reduced in size, which is disadvantageous in terms of cost.

In the present invention, in addition to the monomers of the above general formulas (I), (II) and (III), other monomers can also be used. For example, (meth) acrylamide which is a monomer corresponding to the above general formula (V) can be used. When used as a polymerization component, a decrease in the fluorescence intensity of the fluorescent dye can be suppressed. Further, the viscosity of the obtained aqueous dispersion of the polymer is reduced, and the concentration of the product can be increased. In this case, the combined molar ratio of (meth) acrylamide is 0.5 to 30 in all the monomers used.
%, Preferably 1 to 20%.

Examples of the other monomers include (meth) acrylonitrile, olefin, vinyl ether, allyl ester, vinyl ketone, vinyl sulfonamide, N-vinyl-2-pyrrolidone, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, -Alkyl (meth) acrylamide, divinylbenzene, methylenebisacrylamide, (meth) acrylic acid, maleic acid, fumaric acid, cinnamic acid, itaconic acid, allylamine, diallylamine, vinylpyridine, N-ethyl-4
Vinyl monomers such as vinylpyridinium ethosulfate, and one or more of these can be used.

As a method for polymerizing the polymer used in the present invention, a polymerization reaction is carried out on the above-mentioned monomer by using a solution polymerization or a bulk polymerization in the presence of a radical polymerization initiator. The obtained polymer is dispersed in water directly or together with an additive such as a dispersant, and the solvent is distilled off, if necessary, to adjust the solid content to a predetermined value. Thus, a polymerized polymer sizing agent is obtained.

The alkyl ketene dimer sizing agent used in the present invention is an aqueous dispersion containing an alkyl ketene dimer represented by the following general formula (IV).

(In the formula, R ₇ and R ₈ are the same or different and represent a hydrocarbon group such as an alkyl group or an alkenyl group having 6 to 30 carbon atoms.) These alkyl ketene dimers may be used alone or in combination of two or more. Can be

The method for producing the alkyl ketene dimer sizing agent is, for example, to prepare the alkyl ketene dimer in an aqueous solution together with a protective colloid or a dispersant, or both at a temperature not lower than the melting point of the alkyl ketene dimer represented by the general formula (IV). It is obtained by mixing and uniformly dispersing with various emulsifiers such as a homomixer, a high-pressure discharge homogenizer, and an ultrasonic emulsifier.

Examples of protective colloids and dispersants include cationic dispersants such as cationized starch and polydiallyldimethylammonium halide, anionic dispersants such as naphthalenesulfonic acid-formaldehyde condensate and ligninsulfonate, and nonionics such as sorbitan esters. Examples include dispersants, polymer protective colloids such as cationic, anionic and amphoteric acrylamide polymers. These may be used alone or in combination of two or more.

The amount of the polymerized polymer sizing agent used in the present invention based on the dry pulp is preferably 0.01 to 2% based on the dry pulp.
The amount of the alkyl ketene dimer-based sizing agent is 0.01 to 2%, preferably 0.03 to 1%, based on the dry pulp. Addition rate of these sizing agents is 0.01%
If it is less, the size effect is not sufficient, and if it is more than 2%, the cost is high.

The combined ratio of the polymerized polymer-based alkyl ketene dimer-based sizing agent is 1/99 to 99/1, preferably 5/95 to
95/5.

The place where the polymerized polymer-based size and the alkyl ketene dimer-based sizing agent used in the present invention are added in the papermaking step is not limited, but is preferably from the seed box to just before the screen, and in the pulp slurry, It is desirable that the agent be sufficiently dispersed. There is no restriction on the order of addition, the polymerized polymer sizing agent first,
Then, the alkyl ketene dimer-based sizing agent may be added in order, or vice versa, or they may be added simultaneously.

The above sizing agent can be used in the production of paper or paperboard,
Specifically, neutral printing writing paper, neutral coated base paper, neutral PP
It can be used in the production of C paper, neutral pure white, neutral liners, canned liners, etc.

In producing the above various papers or paperboards,
Pulp raw materials include bleached or unbleached high-yield pulp such as bleached or unbleached chemical pulp such as kraft pulp or sulfite pulp, groundwood pulp, mechanical pulp, or thermomechanical pulp, newspaper waste paper, magazine waste paper, cardboard waste paper or waste paper. Any of used paper pulp such as used ink paper can be used. In addition, a mixture of the above pulp raw material and asbestos, polyamide, polyester, polyolefin and the like can also be used.

In addition, fillers, dyes, dry paper strength agents, retention agents,
Additives such as a drainage improver may be used as needed to exhibit the physical properties required for each paper type. Fillers include clay, talc, kaolin, titanium oxide,
Heavy or soft calcium carbonate may be mentioned, and these may be used alone or in combination.

Examples of the retention aid include bansulfate, anionic or cationic high molecular weight polyacrylamide, a combination of silica sol and cationized starch, and a combination of bentonite and anionic or cationic high molecular weight polyacrylamide.

Examples of the drainage improver include polyethyleneimine and cationic polyacrylamide. Further, starch, polyvinyl alcohol, dye, coating color, surface sizing agent, anti-slip agent and the like may be applied as required by a size press, a gate roll coater, a bill blade coater, a calender or the like.

〔Example〕

Hereinafter, the present invention will be specifically described with examples.
The present invention is not limited to the embodiments.
In the following Examples and Comparative Examples, "%" means "% by weight of solid content" unless otherwise specified.

Production Example 1 of Polymerized Polymer Sizing Agent 1 liter of 4 equipped with a stirrer, thermometer, and cooling pipe
In a one-necked flask, 72.9 g of styrene, 9.2 g of 2-ethylhexyl acrylate, N-ethyl-N, N-dimethyl- (2
-Methacryloyloxyethyl) ammonium bromide 53.2 g, 50% acrylamide aqueous solution 7.1 g, isopropyl alcohol 141 g, azoisobutylnitrile 2 g,
The reaction was carried out at 80 ° C. for 5 hours in a nitrogen stream. Next, 412 g of water was added, and the mixture was thoroughly stirred and dispersed in water, followed by cooling to obtain 700 g of a polymerized polymer sizing agent A. Its solids content was 20%.

Production Example 2 of Polymerized Polymer Sizing Agent Polymerized polymer sizing agents BF were produced in the same manner as in Example 1, except that the monomer composition was changed to the monomer composition shown in Table 1.

In the table, Me: methyl group, Et: ethyl group, Bz: benzyl group, St: styrene, AAM: acrylamide, EHA: 2-ethylhexyl acrylate, EHM: 2-ethylhexyl methacrylate, BA: butyl acrylate, Epi: epichlorohydrin , Ac ⁻ : acetate ion. % Represents mol%.

Comparative Production Examples 1-2 of Polymerized Polymer Sizing Agents Polymerized polymer sizing agents G and H were produced in the same manner as in Example 1, except that the monomer compositions shown in Table 1 were used.

Comparative Production Example 3 of Polymerized Polymer Sizing Agent 1 liter 4 equipped with a stirrer, thermometer and cooling tube
In a two-necked flask, 83.3 g of styrene, 31.4 g of N, N-dimethylaminoethyl methacrylate (hereinafter abbreviated as DM), 118 g of benzyl, and 2 g of azoisobutylnitrile were placed and reacted at 80 ° C. for 5 hours in a nitrogen stream. Then add 425g of acetic acid solution
The mixture was heated to 97 ° C and benzene was distilled off. After distilling off, replenish the distilled water and add 18.5 g of epichlorohydrin.
After reacting at a temperature of 3 ° C. for 3 hours, the mixture was cooled to obtain 670 g of a polymer-based size system I. Its solids content was 20%. The styrene / DM molar ratio of the polymer sizing agent I was 80/20,
Was quaternized with epichlorohydrin.

Example 1 A 2.5% pulse slurry (BKP L / N = 8/2, Canadian Standard Freeness 390 ml) was added to a fluorescent dye (MIKEPHO).
R BX, Mitsui Toatsu Chemicals Co., Ltd.) 0.01%, Light calcium carbonate (Tamapearl 121, Okutama Kogyo Co., Ltd.) 10
%, And after stirring for 2 minutes, cationized starch (Kate F,
0.6% of Oji National Co., Ltd.)
Stirred for minutes. Next, the pulp slurry was diluted to 0.25%, and the alkyl ketene dimer system size (Harcon 701,
Dick Hercules Co., Ltd.) 0.05% and polymerized polymer sizing agent A 0.2% were added, then a yield improver (Hiretene 104, Dick Hercules Co., Ltd.) was added 0.02%, and after stirring for 1 minute, A wet paper having a basis weight of 70 g / m ² was obtained using a hand-making apparatus manufactured by Noble & Wood. At this time, the papermaking pH was 8.0. This wet paper was pressed and then dried at 80 ° C. for 80 seconds with a drum dryer.

Immediately after making the obtained handmade paper and in a constant temperature room at a humidity of 65% and a temperature of 20 ° C. for 24 hours, measure the degree of stake hinoki size according to JIS P-8122, and wet it according to JIS P-8135. The breaking length was measured. The fluorescence intensity was measured using a spectrofluorometer FR-
The fluorescence intensity at 443 nm was measured using 770 (manufactured by JASCO Corporation). The higher the measured value, the higher the fluorescence intensity.

Further, a disaggregation test was performed as follows. First, 5 g of each hand-made paper was finely cut into 1 cm squares, permeated with 1 liter of water, and stirred at 2800 rpm for 10 minutes to observe the degree of looseness of the paper pieces. ○ indicates that the paper piece was completely unraveled in a fibrous state, and x indicates that the paper piece was still unraveled and remained. Generally, the higher the wet strength, the worse the disintegration tends to be. Table 2 shows the measurement results.

Examples 2 to 6 In Example 1, papermaking was carried out in the same manner as in Example 1 except that BF was used in place of the polymer sizing agent A, and the results of measurement in the same manner as in Example 1 are shown in Table 2.

Comparative Examples 1 to 3 Paper was made in the same manner as in Example 1 except that G to I was used in place of the polymer sizing agent A, and the results of measurement in the same manner as in Example 1 are shown in Table 2.

Comparative Example 4 A paper was made in the same manner as in Example 1 except that the polymer sizing agent A was not used, and the results of measurement in the same manner as in Example 1 are shown in Table 2.

From the above results, Examples 1 to 6 show a better sizing effect than Comparative Example 3, the sizing degree is almost the same immediately after production and one day later, and the rising of the sizing degree is also good.
Further, it can be seen that the disintegration property of the broke is good, and the fluorescence intensity of the fluorescent dye is little affected. This is the effect of using the polymerized polymer sizing agent and the alkyl ketene dimer sizing agent in combination. Particularly, the improvement of the disintegration is remarkable, which is an effect of the polymerized polymer sizing agent. Example 1
~ 6 have better size effect than Comparative Examples 2 and 3, which is the effect of introducing the molecular structural unit of general formula (II),
It can be seen that the polymer into which (meth) acrylamide has been introduced is less likely to further decrease the fluorescence intensity of the fluorescent dye.

〔The invention's effect〕

According to the present invention, it has a molecular structural unit of the above general formula,
A polymer-based sizing agent containing a polymer obtained from a monomer composition in which the monomer corresponding to the general formula (I) is 60 to 95 mol% dispersed in water and an alkyl ketene dimer-based sizing agent are used in a papermaking system. , A sizing method for papermaking which is excellent in size effect, has good disintegration, and does not lower the fluorescence intensity of the fluorescent dye, and a paper obtained by the sizing method can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsugumi Ikegaya 17-2 Yawata Kaigan-dori, Ichihara-shi, Chiba Inside Dick Hercules Co., Ltd. (72) Inventor Mariko Shiina 17-81 Yawata Kaigan-dori, Ichihara-shi, Chiba 2 Dick Hercules Co., Ltd. Laboratory (56) References JP-A-63-270893 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21H 17/37 D21H 17/05 D21H 17/71 D21H 21/14

Claims (3)

(57) [Claims] 1. A monomer having at least molecular structural units represented by the following general formulas (I), (II) and (III), wherein a monomer corresponding to the general formula (I) is 60 to 95 mol%. A polymerized polymer sizing agent containing a polymer obtained from the composition dispersed in water and a sizing agent containing a ketene dimer compound represented by the following general formula (IV) are separately added to a papermaking system. Sizing method for papermaking. General formula (I) (Wherein R ₁ is H or CH ₃ , R ₂ is H or CH ₃ , —CH (CH ₃ )
_2, a lower alkyl group such as -C (CH _{3) 3.} ) General formula (II) (In the formula, R ₃ represents H or CH ₃ , and R ₄ represents an alkyl group having 1 to 22 carbon atoms or an alkenyl group having _{3 to} 22 carbon atoms, a cyclohexyl group, a phenyl group, a benzyl group, or a glycidyl group.) (III) (Wherein, R ₅ is an alkyl group having 1 to 22 carbon atoms, 3 to 22 carbon atoms)
Shows the alkenyl group or a benzyl group, R ₆ is hydrogen or a methyl group, A is an oxygen atom or -CH ₂ NH-, X ^- represents an anion. ) General formula (IV) (In the formula, R ₇ and R ₈ represent the same or different hydrocarbon groups having 6 to 30 carbon atoms.) 2. The paper sizing method according to claim 1, wherein the polymer is a polymer having a molecular structural unit represented by the following general formula (V). General formula (V) (In the formula, R ₉ represents H or CH _3. ) 3. A paper obtained by the sizing method for papermaking according to claim 1.