JP3145154B2 - Papermaking additive and papermaking method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. 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 drainage property of papermaking and the drying property of wet paper and enhances paper strength, and produces paper with good paper strength by using the additive. The present invention relates to a method for producing the composition with good efficiency.

[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 productivity due to speeding up of a paper machine in a paper making process or improving quality according to diversification of paper. Additives for enhancing the paper strength are used. Such additives include:
Usually, cationic polymers such as nonionic, anionic and cationic poly (meth) acrylamide-based polymers, polyethyleneimine and polyamide epichlorohydrin-based resins are used.

[0003] A method of producing various papers having excellent strength by improving the drainage properties, drying properties, formation, etc. by using a cationic polymer and bentonite together (Japanese Patent Application Laid-Open No. 62-191598). There has been proposed a method of producing paper (JP-A-64-85398) in which an amphoteric (meth) acrylamide polymer and bentonite are used in combination and the drainage property is improved without reducing the strength of the paper. I have.

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

[0005] However, all of these methods are:
It is not always satisfactory to improve the drying property of paper by improving the freeness.

[0006]

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of the conventional drainage improvers and paper strength enhancers, and improves the drainage during papermaking and the drying of wet paper. Another object of the present invention is to provide a papermaking additive that enhances paper strength and a method for producing paper having good paper strength with high productivity using the additive.

[0007]

Means for Solving the Problems As a result of intensive studies on additives for papermaking, the present inventors 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 copolymer, as an additive for papermaking, has favorable properties, such as enhancing the drainage and drying properties of wet paper and enhancing the paper strength, and using this in the papermaking process together with bentonite As a result, they have found that paper having good paper strength can be produced with high productivity, and based on this finding, the present invention has been completed.

That is, the present invention relates to (A) at least one selected from acrylamide and methacrylamide.
A mixture of unsaturated unsaturated amides and an anionic vinyl monomer in an amount not exceeding 10 mol%, and (B) 0.01 to 0.5 mol%, based on the total amount of the components (A), of a trifunctional vinyl system. A papermaking additive comprising a Mannich reaction product of a crosslinked copolymer with a monomer, and adding the additive to a pulp suspension at a rate of 0.01 to 2 parts by weight per 100 parts by weight of solids, At a ratio of 0.01 to 5 parts by weight, respectively, to provide a papermaking method for papermaking.

The papermaking additive of the present invention comprises a Mannich reaction product of a (meth) acrylamide crosslinked polymer. Conventionally, Mannich-modified polyacrylamide-based drainage agents are generally Mannich-modified cationic polyacrylamides of high molecular weight polyacrylamides having a molecular weight of 1,000,000 or more. It's being used. However, although such Mannich-modified polyacrylamide is good for the formation of flocs of fine fibers, the flocs are re-dispersed due to mechanical shock, the paper layer formation on the wire part becomes uneven, and when used in combination with bentonite. However, it is not sufficient to improve the dryness of wet paper by forming a desired good formation and improving the freeness.

On the other hand, the papermaking additive of the present invention comprises:
(A) acrylamide or methacrylamide and an anionic vinyl monomer, and (B) a polymer having a crosslinked structure obtained by copolymerizing a trifunctional vinyl monomer, obtained by a Mannich reaction, By using the bentonite in combination, it is possible to improve excellent drainage and drying properties without deteriorating the formation, and to give a paper having good paper strength.

In the present invention, as the component (A) forming the (meth) acrylamide-based crosslinked polymer, at least one selected from acrylamide or methacrylamide and an anionic vinyl monomer are used. A mixture is used, but a mixture of acrylamide and an anionic vinyl monomer is preferable from the viewpoint of economy.

The anionic vinyl monomers used in this case include, for example, monocarboxylic acids such as acrylic acid and methacrylic acid, dicarboxylic acids such as itaconic acid, fumaric acid and maleic acid, and sodium salts of these carboxylic acids. And potassium salts and ammonium salts. These anionic vinyl monomers may be used alone or in combination of two or more, and the amount used is selected within a range not exceeding 10 mol% based on the monomer components. . Optimum usage is papermaking pH
Therefore, it is desirable to select appropriately within the above range.

Further, examples of the trifunctional vinyl monomer used as the component (B) include 1,3,5-triacryloylhexahydro-S-triazine, triallyl isocyanurate, N, N-diallylacrylamide and the like. Can be mentioned. One of these trifunctional vinyl monomers may be used alone, or two or more thereof may be used in combination. The amount of the trifunctional vinyl monomer is 0.01 to 0 based on the total amount of the component (A). It is necessary to select in the range of 0.5 mol%, preferably in the range of 0.02 to 0.3 mol%. If the amount is less than 0.01 mol%, the effect of improving the drainage is insufficient, and if it exceeds 0.5 mol%, the obtained copolymer becomes insoluble in water, 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),
Radical polymerization initiators such as redox polymerization initiators combining persulfates such as potassium persulfate and ammonium persulfate or reducing agents such as sodium bisulfite, and, if necessary, chains such as isopropyl alcohol and allyl alcohol A desired crosslinked polymer can be produced by adding a transfer agent and heating for polymerization. The crosslinked polymer thus obtained is usually 3
It has a viscosity average molecular weight of 10,000 to 3,000,000.

In the present invention, the crosslinked polymer thus obtained is subjected to a Mannich reaction. 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 can be obtained by adding formaldehyde and amines such as dimethylamine, diethylamine and diethanolamine to the crosslinked polymer and reacting them. The Mannich reaction product is preferably a product 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 is mainly composed of montmorillonite, and for example, sodium bentonite, calcium bentonite, and activated bentonite such as sodium carbonate and sodium oxalate are used. Among these, activated bentonite is particularly preferable. .

The bentonite may be added to the pulp suspension directly by adding its powder,
It is preferable from the viewpoint of workability that a bentonite slurry having a concentration of about 10% by weight is prepared and added.

The Mannich reaction product of the crosslinked polymer is added in an amount of usually 0.01 to 2 parts by weight, preferably 0.02 to 1 part by weight, per 100 parts by weight of solids of the pulp slurry. Is selected in the range. On the other hand, the amount of bentonite used is usually 0.01 to 5 parts by weight, preferably 0.02 to 5 parts by weight, per 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 higher branching structure than the Mannich reaction product having a linear structure, the number of contacts between pulp fibers is large and the floc forming ability of the fibers is reduced. It is presumed that it is possible to improve the drainage and drying properties, which are the objects of the present invention, without affecting the paper quality when used in combination with bentonite.

[0020]

The papermaking additive of the present invention comprises a Mannich reaction product of a (meth) acrylamide-based crosslinked polymer and improves the drainage of papermaking and the drying of wet paper during papermaking. This has the effect of increasing paper strength.

According to the method of the present invention, the above (meth)
By using the Mannich reaction product of the acrylamide-based crosslinked polymer and bentonite together, paper and paperboard having good paper strength can be produced with high productivity.

[0022]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Each characteristic was obtained as follows. (1) Filtration speed Using a DDJ manufactured by Kumagai Riki Co., Ltd., pour 600 ml of 0.5 wt% pulp slurry into a container, open the lower cock while stirring at 800 rpm, and filter through a 200 mesh wire mesh. Is 200ml, 300ml, 400ml
The time until becomes is measured. The shorter the time, the better the freeness.

(2) Burst strength The burst strength was determined in accordance with JIS P-8131.

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

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% aqueous acrylamide solution, 10 g of an 80 wt% aqueous acrylic acid solution,
17.8 g of a 0 wt% aqueous sodium hydroxide solution,
0.07 g of 5-triacryloylhexahydro-S-triazine, 2 wt% aqueous solution of sodium hypophosphite 25
g and 430.2 g of ion exchanged water, 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, and
After the temperature was raised to 5 ° C. and maintained for 1 hour, the temperature was raised to 80 ° C., and the temperature was maintained for 2 hours to complete the polymerization.
s (25 ° C.) was obtained.

Next, the polymer was kept at 40 ° C., and 48.97 g of a 50 wt% aqueous dimethylamine solution was added thereto.
31.52 g of a wt% formaldehyde aqueous solution was added, and 3
After reacting for an hour, ion-exchanged water was added to
5.0 wt%, pH 11.4, viscosity 9000 cps (2
5 ° C.) and a Mannich modification product A-2 having a Mannich modification rate of 30 mol% based on acrylamide units.

The Mannich reaction products A-1, A-3, and A-
4, A-5 and A-0 were obtained.

[0030]

[Table 1]

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

Examples 1-5, Comparative Example A pulp slurry [pulp: corrugated cardboard waste paper, Canadian Standard Freeness (CSF) 380 ml] was mixed with aluminum sulfate 1.0 wt.
Parts by weight, 0.4 parts by weight (in terms of solid content) of each of the Mannich reaction products obtained in Preparation Example 1 and 0.2 parts by weight of bentonite (Kunisorp, manufactured by Kunimine Industries Co., Ltd.) were added.
Using a TAPPI standard sheet machine, pH5.
At 0 ° C., and further dried under the conditions of 105 ° C. for 3 minutes (drum dryer) to produce a hand-made paper.

The handmade paper obtained in this way is 20
After conditioning for 24 hours at 65 ° C. and a relative humidity of 65%, the burst strength was measured, and DDJ (Dynamic Drainage Jaws) was performed using pulp slurry at the time of papermaking.
A drainage rate test according to r) was performed. Table 2 shows the results.

[0034]

[Table 2]

From the above results, the Mannich reaction product of the crosslinked polymer of the present invention is more excellent in improving the drainage water than the uncrosslinked polymer Mannich reaction product not using a trifunctional vinyl monomer. It can be seen that the strength of the paper is excellent. Further, it can be seen that the copolymerization ratio of the anionic vinyl monomer to acrylamide is sufficient to be 10 mol% or less from the effect of improving the drainage.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-114911 (JP, A) JP-A-2-61197 (JP, A) JP-A-1-92499 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) D21H 17/00-27/42

Claims (2)

(57) [Claims] 1. A mixture of (A) at least one unsaturated amide selected from acrylamide and methacrylamide and an anionic vinyl monomer in an amount not exceeding 10 mol%, and (B) a component (A) 0.0 based on the total amount of
A papermaking additive comprising a Mannich reaction product of a crosslinked copolymer with 1 to 0.5 mol% of a trifunctional vinyl monomer. 2. A papermaking method comprising 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 a pulp suspension per 100 parts by weight of the solid content. A papermaking method characterized by the following.