JPH08144189A - Method for fixing rosin-based sizing agent - Google Patents

Abstract

PURPOSE: To provide a method for fixing a rosin-based sizing agent, capable of improving sizing effect by improving yield of the rosin-based sizing agent. CONSTITUTION: This method for fixing a rosin-based sizing agent comprises adding a rosin-based sizing agent-fixing agent comprising a polymer of plural kinds of water soluble monomers containing 5-90mol% of acryloyloxy ethyltrimethylammonium salt as an essential component and having 18 intrinsic viscosity [η] (intrinsic viscosity in 4% common salt at 25 deg.C) to papermaking raw material slurry containing a rosin-based sizing agent for making neutralized paper and making the mixture into paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rosin-based fixing method, and more specifically, it contains a rosin-based sizing agent and a special water-soluble polymer is added to a neutral to alkaline papermaking raw material slurry. The present invention relates to a fixing method of a size for improving the size effect by making paper.

[0002]

2. Description of the Related Art Alkenyl succinic anhydride (hereinafter abbreviated as ASA) and then alkyl ketene dimer (hereinafter abbreviated as AKD) are the most commonly used sizing agents for neutral papermaking. .

However, each of these neutral sizing agents has problems. ASA can be easily synthesized as a derivative of petroleum products and is available in large quantities as a raw material.
Since it easily decomposes when brought into contact with water, it is emulsified with a cationic polymer as an emulsifier and a fixing agent at the time of paper making and added to the raw material slurry. The emulsified particles not adsorbed on the product raw material decompose and flow out into white water. The collected emulsified particles in white water do not contribute to the size effect even if they are adsorbed again on the wire, and gradually decompose to cause pitch trouble.

On the other hand, since AKD is derived from animal fats and oils, the raw material is limited, and even if it is adsorbed to a papermaking raw material, the size effect does not appear immediately after drying, and the coated raw paper is machined on-machine. Cannot be achieved, and the friction coefficient of the paper is reduced, so that the papers become slippery.

Under these circumstances, a rosin sizing agent for neutral papermaking (hereinafter abbreviated as neutral rosin) has been developed and gradually spread. But neutral rosin also has problems. That is, since the surface charge is anionic, it reduces the aggregation ability of the retention aid added later.

In order to cope with this point, a method of neutralizing the surface charge of neutral rosin by adding a large amount of cation-modified starch is generally used. However, due to this treatment, the zeta potential of the papermaking system becomes around 0 millivolts or becomes positive, the aggregation ability of the retention agent is not improved, and the total retention rate on the wire is not improved. As a result, the size effect is sufficiently expressed. do not do.

The reason for this is that since the retention aid is a high molecular weight cationic polymer, the aggregation mechanism has a small neutralizing effect on the surface charge and is mainly caused by crosslinking and adsorption. In other words, since the cation-modified starch is added at the beginning, it is considered that this is because the number of adsorption sites of the retention agent to be added later becomes extremely small.

For the purpose of improving this formulation, a formulation in which a part of the cation-modified starch is replaced with a synthetic low molecular weight cationic polymer is considered, and is applied to AKD (Japanese Patent Laid-Open No. 55-12868). , Has not yet been applied to neutral rosin.

Further, a method of adding sol-like aluminum hydroxide in the neutral and alkaline pH range for fixing the rosin-based sizing agent (JP-A-1-239198) or a method of adding basic polyaluminum sulfate (JP-A-HEI) 6-
17398), or a method of adding calcium carbonate surface-treated with a cationic water-soluble polymer as a filler when using a neutral rosin (JP-A-6-92007).
However, in both cases, the floc forming ability of the papermaking raw material is too weak, the total yield on the wire is not sufficient, and as a result, the size effect is not improved.

[0010]

The rosin-based sizing agent is generally anionic, but in acidic papermaking, a large amount of a sulfuric acid band is added, so that the papermaking system becomes acidic, and thus the function of the retention aid is improved. There are relatively few factors that inhibit
However, in neutral and alkaline papermaking, neutralization of the surface charge of the rosin-based sizing agent poses a serious problem.

When a large amount of polycationic substance is added, the surface charge is neutralized, but the zeta potential of the papermaking system shifts to 0 or positive to weaken the function of the retention aid, and the retention of the papermaking raw material on the wire. Rate, resulting in a reduction in size yield and no improvement in size.

The current amount of neutral rosin added, 0.4 to 0.7% of the raw material for papermaking is 0.15 to 0.2% of the amount of acidic papermaking.
It is much higher than%. This cause is also due to the performance of neutral rosin itself, but another cause is the retention rate.
If the yield rate is improved, the addition amount will be reduced and not only the cost will be reduced, but also the papermaking system bitch trouble will be reduced, which is important.

An object of the present invention is to provide a method of fixing a rosin-based sizing agent which improves the sizing effect by improving the retention rate of the rosin-based sizing agent.

[0014]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found that acryloyloxyethyl trimethyl containing a neutral rosin in a pH 7-10 papermaking raw material slurry. The present invention has been accomplished by discovering that the size effect is improved by adding a water-soluble polymer composed of a plurality of water-soluble monomers containing an ammonium salt as an essential component for papermaking.

The contents of the invention will be described in detail below. The monomer constituting the water-soluble polymer used in the present invention contains acryloyloxyethyltrimethylammonium salt (hereinafter abbreviated as DMQ) as an essential component. Chloride is the most common example of a specific monomer. The reason for using DMQ is that the degree of polymerization is sufficiently high, a crosslinking reaction does not occur, the solubility in water is excellent, and a polymer having an appropriate cation density is obtained.

Therefore, it is possible to produce a water-soluble polymer having good performance by using methacryloyloxyethyltrimethylammonium salt or dimethyldiallylammonium salt which are other typical cationic monomers. The proportion of DMQ in the monomer is 5 to 90 mol%, preferably 10 to 80 mol%, and more preferably 20 to 60 mol%.
When it is 5 mol% or less, the charge density of the water-soluble polymer is not sufficient and the effect of the size fixing agent is poor. If it is 90 mol% or more, the charge density of the water-soluble polymer becomes too high, which is not preferable because it adversely affects the papermaking system.

Acrylamide is the most common nonionic monomer to be copolymerized, and the acrylamide content in the monomer is usually 0 to 95 mol%, preferably 10 mol%.
~ 90 mol%, more preferably 30 mol% to 80 mol%
Is. Other copolymerizable monomers include anionic monomers, and the anionic monomer content in the monomers is usually 0 to 10 mol%. Specific examples of the anionic monomer include acrylic acid, methacrylic acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid and the like.

The fixing agent comprising the water-soluble copolymer of the present invention can be obtained by copolymerizing the above-mentioned cationic monomer, anionic monomer and nonionic monomer.

The polymerization generally proceeds by radical polymerization, and if the aqueous solution polymerization is carried out as it is after adjusting the aqueous monomer solution to a pH of about 3 to 4.5, the monomer concentration is 10 to 40. Polymerize in%. If reverse phase emulsion polymerization is to be carried out, a suitable paraffinic or aromatic hydrocarbon with an emulsifier having a low HLB is used to reverse phase emulsify in a W / O state, and the monomer concentration is 20 to 50%. Polymerize using a water-soluble or oil-based polymerization initiator.

In the case of producing a copolymer having a relatively high viscosity such as the fixing agent of the present invention, reverse phase emulsion polymerization can be said to be a suitable polymerization method. In addition, when polymerizing with an aqueous solution having a monomer concentration of 40%, a rubber-like gel is formed after polymerization, but after granulating with a meat chopper, etc., drying and pulverizing appropriately, powdery copolymer A coalescence is obtained. Various other polymerization methods are conceivable and are not particularly limited.

Next, the viscosity of the copolymer of the present invention will be described. The viscosity of the copolymer used in the present invention is higher than that of a commonly used fixing agent or retention agent. The reason for this is presumed as follows. First, the function of the high molecular weight cationic polymer partially neutralizes the surface charge of the fine particles dispersed in water. Further, the polymer chains connect the particles to each other and form macro flocs by so-called cross-linking adsorption. Due to this floc formation, the rosin particles are simultaneously aggregated together with the pulp fibers, filler, etc. in the papermaking raw material and taken into the flocs.

At this time, if the surface charge of the rosin particles is not sufficiently neutralized, it is difficult for the rosin particles to be incorporated in the flocs of the pulp and the filler. Therefore, it is necessary to neutralize the surface charge to such an extent that the retention agent added later is not affected by the cation-modified starch or the like used in combination.

If a low-molecular weight cationic polymer is used in combination with the cation-modified starch instead of the high-molecular weight cationic polymer, the surface charge is mainly neutralized because of the low molecular weight. Also, formation of flock is unlikely to occur. Further, not only the rosin particles but also the filler particles, the pulp and the like have a zeta potential approaching 0, and the effect of the retention improver added after the zeta potential decreases.

On the other hand, when the water-soluble copolymer of the present invention is used, a part of the surface charge of the rosin-based sizing agent is neutralized with cation-modified starch, and the surface charge is neutralized with the water-soluble copolymer. Macroscopic flocs are formed by cross-linking adsorption, and size particles are also incorporated into the macroscopic flocs. At this time, if a sufficient total retention rate can be achieved on the wire and the addition amount is such that the formation of the paper is not a problem, the retention agent is not required to be used in combination. The combined use of the retention agent is comprehensively judged such as the place of addition in the paper manufacturing process, the retention rate, the formation, and the cost. In addition, so-called dual prescription is possible by examining multiple places of addition during the paper manufacturing process.

For the reasons described above, the viscosity of the water-soluble copolymer of the present invention has an intrinsic viscosity [η] of 8 or more when measured in 4% saline. Since the rosin-based sizing agent is generally anionic, it tends to hinder the aggregation function of the retention agent.
Therefore, if it is less than 8, a sufficient aggregation function is not obtained and the yield of the rosin-based sizing agent is not improved.

Next, the polymer concentration in the case of adding the water-soluble polymer of the present invention to the papermaking raw material slurry, the place of addition in the papermaking process, and the combination with other chemicals will be described.
First, the polymer concentration is not constant depending on the product viscosity,
If it is diluted to 0.05 to 0.2%, sufficiently good dispersibility can be obtained. Next, at the place of addition, according to the present invention, macroscopic flocs are formed by the high-viscosity fixing agent, and the flocs of an appropriate size are broken by the shear received by the slurry.

If this floc is broken too finely, the retention rate of pulp, filler, and sizing agent on the wire will be reduced. Therefore, filler, sulfuric acid band, sizing agent,
In the place where cation-modified starch, paper strengthening agent, etc. are added, the process until papermaking on the wire is too long and the flocs are destroyed too much.

Therefore, possible places of addition may be before a point called a fan pump where white water is mixed and diluted to about 0.5% which is a papermaking concentration, or before and after a lamo screen for removing foreign matters.

When other chemicals to be used in combination, such as bentonite or colloidal silicate, are used together, the water-soluble copolymer of the present invention is in front of the fan pump, the retention aid is in front of lamoscreen, bentonite or the like. For the colloidal silicate, the water-soluble copolymer of the present invention is added in front of the fan pump or in front of the lamoscreen in the case of the two-part addition of the outlet and the fixing agent and the retention aid. Before or after, when the fixing agent is used alone, it is added before the lamoscreen or at the outlet.

If a dual formulation is carried out with the fixing agent of the present invention, the fixing agent is added before the fan pump and bentonite or colloidal silicate is before and after the lamoscreen.

Next, the rosin-based sizing agent which is a target of the fixing agent of the present invention will be described. The rosin-based sizing agent has been used as a sizing agent for acidic papermaking in almost all acidic papermaking systems when it is subjected to sizing treatment.
A neutral papermaking rosin sizing agent was developed to supplement KD.

The rosin sizing agent for acidic papermaking (hereinafter abbreviated as acidic rosin) exhibits a certain degree of sizing degree even if it is neutral or weakly alkaline, without the use of a sulfuric acid band. However, when calcium carbonate is used as the filler, the pH is slightly increased to around 8 and the size effect is hardly exhibited. That is, it is easily affected by calcium carbonate.

The property of acidic rosin is improved by neutral rosin in the presence of calcium carbonate, pH 7.0-10.
A size effect is sufficiently exhibited even near 0. However, there is a drawback that the size effect is not sufficient and the addition amount is large as described above. Further, ASA and AKD can be cationically charged if an emulsification aid is appropriately selected, but neutral rosin has not yet established a technique for producing such a stable dispersion.

Since it is anionically charged, there is no problem in acidic papermaking in which an appropriate amount of sulfuric acid band can be added, but in alkaline papermaking in which calcium carbonate is added, the addition amount of the sulfuric acid band is limited, and the sulfuric acid band is a weak cation. Since it becomes a polymerizable hydroxide that is only charged, it is not useful for neutralizing the surface charge of the rosin particles, and becomes a coagulation inhibiting factor for the retention agent added later. Therefore, the fixing agent of the present invention plays an important role.

The fixing agent of the present invention exerts an effect even when used in combination with a sulfuric acid band as a fixing agent for a general acidic rosin in a neutral to weakly alkaline state to which calcium carbonate is not added, but its characteristics are well exhibited. In the case of making paper using neutral rosin.

Further, there is a problem of the order of addition of the fixing agent of the present invention and other paper-making chemicals, which should be properly examined according to the situation at the papermaking site. As a temporary basic order of addition, a filler, a dye, a cation-modified starch, a paper strengthening agent, a sulfuric acid band, a rosin-based sizing agent, etc. are added and mixed into the raw material pulp slurry. At this time, when the fixing agent is used alone, the fixing agent is added after this.

If a retention agent is used in combination, the order is fixing agent and retention agent. In the case of a dual formulation, bentonite or colloidal silicate is added in this order after the fixing agent and the retention agent. However, this is not a fixed one, and it is most suitable for the total yield, size, and
Also, consider a prescription that improves texture.

The amount of the fixing agent of the present invention to be added is 0.002% to 0.1% with respect to the raw material for paper making, but this is not uniquely determined either. For example, 0.02% to 0.08% when the fixing agent is used alone, and 0.0 when the retention agent is used in combination.
05% -0.03%, 0.005%-
It will be in the range of 0.03%.

As the filler to be used in the present invention, any of various known fillers used in the conventional papermaking process can be used. In the case of alkaline papermaking, heavy calcium carbonate or light calcium carbonate is used. Can, but p
If papermaking is carried out before and after H7, kaolin, titanium dioxide clay, clay, synthetic silica and the like can be used.

When sizing with a rosin-based sizing agent during the papermaking process, it is common to use a sulfuric acid band together, and as a result, acidic papermaking becomes acidic at pH 4 to 6.
If the pH of papermaking is around 7.0 to 7.5 and if a filler other than calcium carbonate is used, sizing can be performed using acidic rosin without a sulfuric acid band. The sulfate band is added using neutral rosin. Since calcium carbonate is used, the addition amount of the sulfuric acid band must be suppressed as small as possible, but the sulfuric acid band is essential for the rosin-based sizing agent. When a sulfuric acid band having a pure alumina content of 8% is added and 0.5% of papermaking raw material is added, the pH is about 8.2, 1% is about 8.1, and 2% is about 8.0. Become. Although it cannot be said uniquely depending on the situation at the papermaking site, in the case of neutral rosin, the sulfuric acid band is required in the range of 1 to 2%. When the fixing agent of the present invention is used, the same amount of sulfuric acid band is added.

[0041]

EXAMPLES The contents of the present invention will be described more specifically below with reference to Examples and Comparative Examples, but the present invention is not limited to these contents.

[Production Example of Water-Soluble Polymer] The cationic monomer, anionic monomer, and nonionic monomer shown in Table 1 are used at a constant mole fraction so that the total weight is 15%. It is dissolved in deionized water and the pH of the solution is adjusted to 3.5. The monomer aqueous solution is kept at 40 ° C., and nitrogen gas is flowed for 30 minutes to remove oxygen in the solution. After that, per monomer,
2,2'-azobisaminodipropane dihydrochloride was added to 100
Add ppm and polymerize at 40 ° C. for 20 hours while flowing nitrogen gas. Then, each solution was put into acetone to precipitate a polymer, which was vacuum dried to obtain a corresponding polymer (trial No.
1-19) was obtained. 0.1% of these in 4% sodium chloride
It was dissolved in each concentration of 0.05, 0.01 and 0.005 g / dl, and the reduced viscosity was measured using an Ostwald viscometer at 25 ° C., and then extrapolated to the concentration of 0 to obtain the intrinsic viscosity [η]. Estimated. Table 1 shows the measurement results of the molar fraction and the intrinsic viscosity of each monomer solution.

[0043]

[Table 1]

(Examples 1 to 10) Hardwood kraft pulp (LBKP) was beaten to CSF-400 ml to a concentration of 0.8.
Adjust to 75%. 1000 ml of this dispersion was sampled and put into a stirrer of a blit type retention tester, and then light calcium carbonate, cation-modified starch, liquid sulfuric acid band, commercially available neutral rosin for papermaking, fixing agent of the present invention (trial No. 2). ~
6) was added at a constant addition amount shown in Table 2 at a stirring intensity of 500 rpm at intervals of 10 seconds. After adding the fixing agent, the mixture was stirred for 15 seconds, and then a fixed amount of the retention aid was added and stirred for 10 seconds. , A 20-mesh wire was used to collect the paper material remaining on the wire, and a paper having a basis weight of 60 g / m ² was made with a square paper machine. Each paper was sandwiched between three filter papers and pressed twice under the conditions of 5 kg / cm ² and 5 minutes. Then, it was dried at 100 ° C. for 1.5 minutes with a rotary drum dryer, adjusted at 65 RH and 20 ° C. in a constant temperature and humidity chamber for 18 hours, and then measured for sizing degree by the Steckigt method. At the same time, 150 ml of initial filtered water was collected, and calcium carbonate and the total retention rate were measured. The above results are summarized in Table 2.

(Comparative Examples 1 to 10) In the same manner as in Examples,
Prototype No. 1 and No. 7 tested. At the same time, a commercial flocculant Age Floc 40 VHV (polydimethyldiallylammonium chloride, manufactured by CPS) (Comparative product 1), Hymolok Q-101 (amine epitarolohydrin resin, manufactured by Himo) (Comparative product 2), Percoll 47
(Allied Colloid Co., Ltd.) (Comparative Product 3) was also tested. The above results are summarized in Table 2.

[0046]

[Table 2]

(Examples 11 to 20) In the same manner as in Examples 1 to 10, the prototype No. 11, No. 12 (change in anionization degree), prototype No. 14, No. 15, No. 16
(Change of anionic monomer) was tested. The results are summarized in Table 3.

(Comparative Examples 11 to 18) Prototype No. 8, No. 9, No. 10 (change of cationic monomer) was also tested. At the same time, a commercial retention aid, Percoll 47 (manufactured by Allied Colloid Co.) (Comparative Product 3) was tested. The results are summarized in Table 3.

[0049]

[Table 3]

(Examples 21 to 26) In order to investigate the effect on the viscosity, as in Examples 1 to 10, the prototype No. 4, N
o. 18, No. 19 were tested. The results are summarized in Table 4.

(Comparative Examples 19 to 22) Prototype Nos. 17 tested. At the same time, Percoll 47 (manufactured by Allied Colloid) (Comparative Product 3) was also tested. The results are summarized in Table 4.

[0052]

[Table 4]

(Examples 27 to 40) In order to investigate the effect of using the fixing agent alone, the trial production No. was performed in the same manner as in Examples 21 to 26 except that the last retention agent was not added. 2, No. Three
No. 4, No. 5, No. 6, No. 11, No. 1
2 tested. The results are summarized in Table 5.

(Comparative Examples 23 to 32) Prototype No. 1, No. 7, No. 17 tested. At the same time, Comparative Product 1 and Comparative Product 3 were also tested. The results are summarized in Table 5.

[0055]

[Table 5]

(Examples 41 to 50) In order to investigate the effect when using bentonite together, a trial production N was performed in the same manner as in Examples 27 to 40.
o. 2, No. 3, No. 4, No. 5, No. 6 tested. The order of addition of each chemical is calcium carbonate, cation-modified starch, liquid sulfuric acid band, neutral rosin, fixing agent of the present invention, bentonite, retention agent. Except for retention agent, stirring is performed for 15 seconds, and after addition of retention agent, 10 Stir for minutes and test. The results are summarized in Table 6.

(Comparative Examples 33 to 40) Prototype No. 1 and No. 7 tested. At the same time, Comparative Product 1 and Comparative Product 2 were also tested. The results are summarized in Table 6.

[0058]

[Table 6]

(Examples 51 to 58) In order to investigate the effect when the colloidal silicate was used in combination, the trial manufacture No. 2, No. 3, No. 4, No. 5 were tested. Table 7 summarizes the results.

(Comparative Examples 41 to 48) Similar to the examples, the prototype No. 1 and No. 7 tested. At the same time, Comparative Product 1 and Comparative Product 2 were also tested. Table 7 summarizes the results.

[0061]

[Table 7]

[0062]

When the rosin-based sizing agent fixing agent of the present invention is used, the sizing effect is improved if the sizing agent is added in the same amount. Therefore, since the amount of the sizing agent added can be reduced, the papermaking cost and pitch troubles can be reduced, which greatly contributes to the papermaking industry.

Claims (6)

[Claims] 1. A plurality of water-soluble monomers containing acryloyloxyethyl trimethylammonium salt as an essential component in an amount of 5 to 90 mol% in a papermaking raw material slurry having a pH of 7 to 10 containing a rosin-based sizing agent for neutral papermaking. A rosin-based fixing agent comprising a polymer having an intrinsic viscosity [η] (intrinsic viscosity in 4% saline solution at 25 ° C.) of 8 or more for papermaking. How to fix the sizing agent. 2. A rosin-based sizing agent according to claim 1, wherein a rosin-based sizing agent comprising a polymer of a water-soluble monomer containing acryloyloxyethyltrimethylammonium salt and acrylamide as essential components is used. Fixing method. 3. A rosin-based size fixing agent comprising a copolymer of a monomer mixture in which the proportion of acryloyloxyethyltrimethylammonium salt in the monomer is 20 to 60 mol%. Item 3. A method of fixing a rosin-based sizing agent according to Item 1 or 2. 4. The rosin-based size fixing agent is added after the aluminum salt is added to and mixed with the papermaking raw material slurry containing the rosin-based sizing agent for neutral papermaking. The method for fixing a rosin-based sizing agent according to item 1. 5. The method according to claim 1, wherein the papermaking raw material containing the rosin-based sizing agent for neutral papermaking and the rosin-based fixing agent can be mixed after the step of diluting with white water. A method for fixing a rosin-based sizing agent as described. 6. The method of fixing a rosin-based sizing agent according to claim 1, wherein the filler contains calcium carbonate.