JPH05125692A - Paper-making additive and paper-making method using the same - Google Patents

Abstract

PURPOSE:To obtain the subject additive effective for increasing paper strength and having excellent freeness, dryability and productivity by compounding a specific mixture with a specific Mannich reaction product at a specific ratio. CONSTITUTION:The objective additive is composed of a Mannich reaction product of a cross-linked copolymer of (A) a mixture of one or more unsaturated amides selected from (meth)acrylamide and <=10mol% of an anionic vinyl monomer and (B) 0.01-0.5mol%, preferably 0.02-0.3mol% (based on the component A) of a trifunctional vinyl monomer (e.g. triallyl isocyanurate). A paper having high paper strength can be produced by adding 0.01-2 pts.wt. of the above additive and 0.01-5 pts.wt. of bentonite based on 100 pts.wt. of the solid content of a pulp suspension and making a paper sheet from the mixture.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel papermaking additive and a papermaking method using the same. More specifically, the present invention provides a papermaking additive that improves the water drainage property during papermaking and the wettability of wet paper, and enhances the paper strength, and a paper having good paper strength using the same. The present invention relates to a method of manufacturing with good performance.

[0002]

2. Description of the Related Art In recent years, in the production of paper and paperboard, various drainage properties have been improved for the purpose of improving the productivity with the speeding up of the paper machine in the papermaking process, or improving the quality according to the diversification of paper. Additives for increasing the strength of the paper are used. As such an additive,
Usually, a nonionic, anionic, or cationic poly (meth) acrylamide-based polymer, or a cationic polymer such as polyethyleneimine or polyamide epichlorohydrin-based resin is used.

A method of producing various papers having excellent strength by improving the drainage property, drying property and formation by using a cationic polymer and bentonite together (Japanese Patent Laid-Open No. 62-191598). , A method for producing paper in which an amphoteric (meth) acrylamide-based polymer and bentonite are used in combination to improve drainage without lowering the strength of the paper (Japanese Patent Laid-Open No. 64-85398). There is.

The former is a method for producing paper or paperboard which improves drainage and drying properties by combining bentonite with a substantially linear synthetic cationic polymer having a molecular weight of 500,000 or more, and the latter is a method for polymerizing (meth) acrylamide. A method for producing a paper in which an amphoteric polymer having an average molecular weight of 100,000 to 1,000,000 used as a component and bentonite are used in combination and the drainage property is improved without lowering the strength of the paper, which is one of the amphoteric compounds. The Mannich reaction product is shown.

However, all of these methods
The improvement of the drying property of paper by the improvement of drainage is not always sufficiently satisfactory.

[0006]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of such conventional drainage improvers and paper strength enhancers, improves drainage during papermaking and dryness of wet paper, In addition, it is an object of the present invention to provide a papermaking additive that enhances paper strength and a method for producing paper having good paper strength with good productivity by using the additive.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on additives for papermaking, and as a result, have found that a crosslinked type obtained by copolymerizing acrylamide or methacrylamide with a specific monomer at a predetermined ratio. The Mannich reaction product of the polymer has, as an additive for papermaking, preferable properties such as improving the drainability of the drainage and the wet paper and increasing the paper strength, and that this product is used in the papermaking process together with bentonite. As a result, it has been found that a paper having good paper strength can be produced with good productivity, and the present invention has been completed based on this finding.

That is, the present invention provides at least one selected from (A) acrylamide and methacrylamide.
An unsaturated amide of a species or a mixture thereof with an anionic vinyl monomer in an amount not exceeding 10 mol%, (B) (A)
A papermaking additive comprising a Mannich reaction product of a cross-linking copolymer with 0.01 to 0.5 mol% of a trifunctional vinyl-type momano, based on the total amount of components, and the additive to a pulp suspension. The present invention provides a papermaking method for making paper by adding 0.01 to 2 parts by weight and 0.01 to 5 parts by weight of bentonite per 100 parts by weight of the solid content.

The papermaking additive of the present invention comprises a Mannich reaction product of a (meth) acrylamide cross-linking polymer. Conventionally, as a Mannich-modified polyacrylamide-based water-removing agent, generally, a cationic polyacrylamide obtained by Mannich-modifying a high-molecular-weight polyacrylamide having a molecular weight of 1,000,000 or more is used for improving the retention and drainage of fine fibers and fillers in a papermaking process. It's being used. However, although such a Mannich-modified polyacrylamide is good for the formation of flocs of fine fibers, the flocs are redispersed by mechanical shock, and the paper layer formation on the wire part becomes non-uniform, and when used in combination with bentonite. However, it is not sufficient to improve the drying property of the wet paper web by forming a desired favorable formation and improving the drainage property.

On the other hand, the papermaking additive of the present invention is
(A) Acrylamide or methacrylamide, optionally obtained by copolymerizing an anionic vinyl-based monomer and (B) a trifunctional vinyl-based monomer, obtained by a Mannich reaction of a polymer having a crosslinked structure Therefore, by using bentonite together, it is possible to improve excellent drainage and drying properties without impairing the formation and to give paper having good paper strength.

In the present invention, acrylamide, methacrylamide, or a mixture thereof is used as the component (A) forming the above-mentioned (meth) acrylamide cross-linking polymer, and acrylamide is preferred from the economical viewpoint. ..

Examples of the anionic vinyl monomer used as desired include monocarboxylic acids such as acrylic acid and methacrylic acid, itaconic acid, fumaric acid,
Examples include dicarboxylic acids such as maleic acid and sodium, potassium and ammonium salts of these carboxylic acids. These anionic vinyl monomers are 1
These may be used alone or in combination of two or more, but the amount used is 10 mol% based on the monomer components.
It is selected within the range. The optimum amount to use is p for papermaking.
Depending on H, it is desirable to select it appropriately within the above range.

Further, as the trifunctional vinyl monomer used as the component (B), for example, 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanurate, N, N-diallyl acrylamide, etc. Can be mentioned. These trifunctional vinyl-based monomers may be used alone or in combination of two or more, and the amount thereof used is 0.01 to 0 relative to the total amount of the component (A). It is necessary to select in the range of 0.5 mol%, preferably 0.02 to 0.3 mol%. If this amount is less than 0.01 mol%, the effect of improving drainage is insufficient, and if it exceeds 0.5 mol%, the copolymer obtained becomes water-insoluble and the object of the present invention cannot be achieved.

The method for producing the crosslinked polymer is not particularly limited, and a conventionally known method can be used. For example, in an aqueous medium, the component (A) and the component (B),
A radical polymerization initiator such as a redox-based polymerization initiator obtained by combining a persulfate such as potassium persulfate or ammonium persulfate or a reducing agent such as sodium bisulfite, and a chain such as isopropyl alcohol or allyl alcohol as necessary. A desired cross-linked polymer can be produced by adding a transfer agent and heating to polymerize. The crosslinked polymer thus obtained is usually 3
It has a viscosity average molecular weight of 0,000 to 3,000,000.

In the present invention, the thus obtained crosslinked polymer is subjected to a Mannich reaction, but the Mannich reaction is not particularly limited, and a conventionally known method can be used. For example, a Mannich reaction product of the crosslinked polymer is obtained by adding formaldehyde and amines such as dimethylamine, diethylamine and diethanolamine to the crosslinked polymer and reacting them. This Mannich reaction product is preferably one in which 20 to 80 mol%, preferably 30 to 60 mol%, of the amide group in the (meth) acrylamide unit is modified by the Mannich reaction.

In the method of the present invention, the Mannich reaction product of the crosslinked polymer thus prepared is used as an additive for papermaking and added to the pulp suspension together with bentonite. The bentonite contains montmorillonite as a main component, and for example, sodium bentonite, calcium bentonite, and active bentonite such as sodium carbonate and sodium oxalate are used. Among them, active bentonite is particularly preferable. ..

This bentonite may be prepared by adding the powder directly to the pulp suspension, but it may be added with water in an amount of 0.5 to 0.5 in advance.
From the viewpoint of workability, it is preferable to prepare a bentonite slurry having a concentration of about 10% by weight and add this.

The amount of the Mannich reaction product of the crosslinked polymer added is usually 0.01 to 2 parts by weight, preferably 0.02 to 1 part by weight, based on 100 parts by weight of the solid content of the pulp slurry. It is selected in the range of. On the other hand, the amount of bentonite used is normally 0.01 to 5 parts by weight, preferably 0.02 to 100 parts by weight of the solid content of the pulp slurry.
It is selected in the range of 3 parts by weight. Regarding the order of addition, it is advantageous to first add the Mannich reaction product of the present invention to the pulp slurry and then add bentonite.

Since the Mannich reaction product having a crosslinked structure of the present invention has a branching structure higher than that of a linear Mannich reaction product, there are many contacts between pulp fibers, and the floc forming ability of the fibers is high. It is presumed that, when used in combination with bentonite, it is excellent and does not affect the paper quality, and it is possible to improve the drainage and drying properties, which is the object of the present invention.

[0020]

The papermaking additive of the present invention comprises a Mannich reaction product of a (meth) acrylamide cross-linking polymer, and improves the drainage and the wettability of wet paper during papermaking. , It has the effect of increasing the paper strength.

According to the method of the present invention, the above-mentioned (meth)
By using the Mannich reaction product of an acrylamide cross-linking polymer and bentonite in combination, paper or paperboard having good paper strength can be produced with good productivity.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Each characteristic was obtained as follows. (1) Drainage speed Using DDJ manufactured by Kumagai Riki Co., Ltd., 600 ml of 0.5 wt% pulp slurry was poured into a container, and while stirring at 800 rpm, the lower cock was opened and filtered through a 200-mesh wire net, and the filtrate was obtained. 200 ml, 300 ml, 400 ml
Measure the time until it becomes. The shorter the time, the better the freeness.

(2) Bursting strength It was determined according to JIS P-8131.

(3) Freeness The freeness was determined according to JIS P-8121. The larger the value, the better the drainage.

Preparation Example 1 In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 184 g of a 50 wt% acrylamide aqueous solution, 10 g of an 80 wt% acrylic acid aqueous solution, 2
17.8 g of 0 wt% sodium hydroxide aqueous solution, 1,3
5-Triacryloylhexahydro-S-triazine 0.07 g, 2 wt% sodium hypophosphite aqueous solution 25
g and ion-exchanged water 430.2 g were charged, and then oxygen in the polymerization system was removed through nitrogen gas.

Next, while stirring, 3 g of a 10 wt% ammonium persulfate aqueous solution was added as a polymerization initiator to obtain 7
After raising the temperature to 5 ° C and keeping it for 1 hour, the temperature is raised to 80 ° C and kept at that temperature for 2 hours to complete the polymerization, and the nonvolatile content is 15.3 wt%, pH 4.5, and the viscosity is 12000 cp.
A cross-linked polymer of s (25 ° C.) was obtained.

Next, this polymer was kept warm at 40 ° C., and 48.97 g of a 50 wt% dimethylamine aqueous solution, 37
Add 31.52 g of wt% formaldehyde aqueous solution and add 3
After reacting for a period of time, ion-exchanged water was added to add a nonvolatile content of 1
5.0 wt%, pH 11.4, viscosity 9000 cps (2
(5 ° C.) and a Mannich reaction product A-2 having a Mannich modification rate of 30 mol% based on the acrylamide unit was obtained.

The Mannich reaction products A-1, A-3 and A- shown in Table 1 were prepared in the same manner as described above by changing the monomer composition.
4, A-5 and A-0 were obtained.

[0030]

[Table 1]

(Note) AM: acrylamide AAC: acrylic acid TAF: 1,3,5-triacryloylhexahydro-
S-triazine

Preparation Example 2 100 parts by mole of acrylamide and 1,3,5-triacryloylhexahydro-S-triazine (TAF)
After obtaining a cross-linked polymer in the same manner as in Preparation Example 1 using 02 parts by mole, Mannich reaction was carried out to obtain a nonvolatile content of 5 wt.
%, Viscosity 3400 cps (25 ° C.), Mannich reaction product B-of a cross-linked polymer having a Mannich modification rate of 50 mol%.
Got 1.

The Mannich reaction products B-2, B-3 and B-shown in Table 2 were prepared in the same manner as described above by changing the monomer composition.
I got 0.

[0034]

[Table 2]

Examples 1 to 5 and Comparative Example 1 Pulp slurry [pulp: corrugated board waste paper, Canadian Standard Freeness (CSF) 380 ml] was added with 1.0 parts of aluminum sulfate per 100 parts by weight of its solid content.
Parts by weight, 0.4 parts by weight of each of the Mannich reaction products obtained in Preparation Example 1 (in terms of solid content) and 0.2 parts by weight of bentonite [Kunithorpe, manufactured by Kunimine Industry Co., Ltd.] were added,
Using a TAPPI standard sheet machine, pH of 5.
Papermaking was performed at 0, and further dried at 105 ° C. for 3 minutes (drum dryer) to produce handmade paper.

The handmade paper thus obtained is used for 20
After conditioned for 24 hours under conditions of ℃ and 65% relative humidity, burst strength was measured, and DDJ (Dynamic Drainage Ja) was measured using pulp slurry at the time of papermaking.
The drainage speed test according to r) was performed. The results are shown in Table 3.

[0037]

[Table 3]

Examples 6 to 8 and Comparative Example 2 In a pulp slurry, 0.03 parts by weight of Mannich reaction product obtained in Preparation Example 2 (solid content basis) and bentonite 0. 2 parts by weight was added and a drainage speed test was conducted in the same manner as in Examples 1-5. Separately, the freeness was measured using the same pulp slurry. The results are shown in Table 4.

[0039]

[Table 4]

From the above results, the Mannich reaction product of the crosslinked polymer of the present invention is superior in the drainage improving effect as compared with the uncrosslinked polymer Mannich reaction product which does not use the trifunctional vinyl monomer. It can be seen that the paper strength is also excellent. Further, it is understood that the copolymerization ratio of the anionic vinyl monomer to acrylamide is 10 mol% or less from the effect of improving drainage.

Claims (2)

[Claims] 1. (A) At least one unsaturated amide selected from acrylamide and methacrylamide or a mixture thereof with an anionic vinyl monomer in an amount not exceeding 10 mol%, (B) (A) A papermaking additive comprising a Mannich reaction product of a cross-linkable copolymer with 0.01 to 0.5 mol% of a trifunctional vinyl-type momano, based on the total amount of components. 2. Paper making by adding 0.01 to 2 parts by weight of the papermaking additive of claim 1 and 0.01 to 5 parts by weight of bentonite to 100 parts by weight of the solid content of the pulp suspension. A papermaking method characterized by: