JPH09302595A - Chemical agent for paper manufacturing and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chemical agent capable of improving paper strength, paper manufacturing yield and freeness, by copolymerization of an N- vinylcarboxylic acid amide and acrylonitrile in specified proportions in the presence of polyvinyl alcohol(PVA) in an aqueous medium followed by conducting a hydrolysis. SOLUTION: This chemical agent for paper manufacturing is obtained by copolymerization of a monomer (mixture) composed of 10-100 (pref. 35-100)mol% of an N-vinylcarboxylic acid amide such as N-vinyl-formamide and 0-90 (pref. 0-65)mol% of acrylonitrile in the presence of PVA in an aqueous medium followed by conducting a hydrolysis. The weight ratio: PVA/monomer is pref. (2:1) to (1:20), and the intrinsic viscosity of the polymer resulted from the hydrolysis is pref. 0.1-10dL/g (in 1N saline solution).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention discloses a novel cationic polymer useful as a paper-making agent and a method for producing the same. The main chain of the polymer is polyvinyl alcohol, and the side chain has a vinylamine structural unit or a vinylamidine structural unit. A paper strengthening agent composed of a novel cationic polymer having
The present invention relates to a retention improver such as size and filler, a drainage improver, and a coating agent used for coating base paper.

[0002]

2. Description of the Related Art Conventionally, a method for producing polyvinylamine by Hoffmann decomposition of polyacrylamide is known. Further, it can be produced by hydrolyzing poly-N-vinylcarboxylic acid amide obtained by polymerizing N-vinylcarboxylic acid amide (JP-A-58-23809).
Also, a water-soluble polymer containing a vinylamino group can be produced by hydrolysis of a copolymer of N-vinylcarboxylic acid amide and vinyl acetate (JP-A-62-74902).
Issue). Copolymerized N-vinyl carboxylic acid amide and acrylonitrile and hydrolyzed this copolymer,
Further, a water-soluble polymer which has been modified at high temperature to be an amidine is also proposed (JP-A-63-165412 and JP-A-6-123096). Since the N-vinylcarboxylic acid amide and the acrylonitrile copolymer are insoluble in water, the copolymer is obtained as a precipitate by polymerizing in an aqueous medium. However, during the polymerization, coalescence of the copolymer particles,
Alternatively, it was previously proposed that a water-soluble polymer or the like be added as a particle size adjusting agent because problems such as adhesion to the wall of the polymerization vessel and agglomeration are likely to occur (Japanese Patent Application No. 7-93258).
issue).

[0003]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a papermaking agent comprising a novel cationic water-soluble polymer which has hitherto been unknown.

[0004]

SUMMARY OF THE INVENTION The present invention comprises 10-100 mol% N-vinylcarboxylic acid amide and 0 acrylonitrile in the presence of polyvinyl alcohol in an aqueous medium.
By copolymerizing a monomer containing ˜90 mol%, it was found that not only agglomeration of the resulting copolymer particles is prevented but also a graft copolymer is produced,
The present invention was completed by discovering that a cationic water-soluble polymer obtained by hydrolyzing the copolymer is useful as a papermaking agent.

Random copolymers of vinyl alcohol structural units and vinylamine structural units have been known, but the existence of a graft copolymer having a main chain of polyvinyl alcohol and a polymer chain containing vinylamine structural units in its side chains. Was not known. Further, the existence of a graft copolymer comprising a polymer chain having a main chain of polyvinyl alcohol and a side chain containing a vinylamine structural unit and a vinylamidine structural unit has not been known.

According to the first aspect of the invention, 10 to 100 mol% of N-vinylcarboxylic acid amide and 0 to 9 acrylonitrile in the presence of polyvinyl alcohol in an aqueous medium.
It is a papermaking agent obtained by copolymerizing a monomer containing 0 mol% and then hydrolyzing it. N-vinylcarboxylic acid amide 35-100 mol%, acrylonitrile 0-65
A side chain composition of mol% is particularly preferred as a papermaking agent.
The graft copolymerization of the present invention can be carried out by polymerizing with an ordinary radical generator under the above conditions. For example, 2,2′-azobis-2-amidinopropane dihydrochloride, 4,4′-azobis-4cyanovaleric acid sodium salt, 2,2′-azobis-N, N′-dimethyleneisobutylamidine dihydrochloride. Azo-based initiators such as, for example, can be preferably used. Further, an oxidation type or redox type initiator may be used in combination with these azo type initiators or may be used alone. The amount of the polymerization initiator used is usually
It is about 100 to 10,000 ppm with respect to the monomer. The molecular weight is adjusted using alcohols such as methanol, ethanol and isopropanol, or sulfur-containing compounds such as 2-mercaptoethanol. The amount used is 0.1 to 20 for alcohols with respect to monomers.
0 wt%, 0.01-1 for 2-mercaptoethanol
0% by weight. Further, in order to suppress the polymer crosslinking derived from the aldehyde contained in the vinylcarboxylic acid amide, it is advisable to add the hydroxylamine salt to the N-vinylcarboxylic acid amide in an amount of 0.1 to 1% by weight. The polymerization reaction is generally carried out after deoxidation under a temperature condition of 30 to 100 ° C. The graft copolymer is analyzed by nuclear magnetic resonance spectroscopy, infrared spectroscopy and the like. In addition, since acrylonitrile and N-vinylcarboxylic acid amide copolymer are water-insoluble, polyvinyl alcohol copolymer having a side chain of the composition is used. In the case of a polymer, the graft amount can be calculated from the amount eluted with water. The addition rate of the produced polymer according to the present invention to polyvinyl alcohol, that is, the grafting rate is 10 to 60%. The graft copolymer exhibits good effects as a paper-making agent even in the state of a mixture with a homopolymer without isolation, and a complicated isolation step is unnecessary. It increases the value of the above.

According to the third aspect of the present invention, 10 to 100 mol% of N-vinylcarboxylic acid amide and 0 to 9 acrylonitrile are contained in an aqueous medium in the presence of polyvinyl alcohol.
It is a papermaking agent characterized in that a copolymer containing 0 mol% of a monomer and then hydrolyzed to produce a polymer has a formula weight ratio of polyvinyl alcohol to the monomer of 2: 1 to 1:20. . In order to obtain a graft copolymer effective as a papermaking agent, it is desirable that the formula weight ratio of polyvinyl alcohol and the monomer is 2: 1 to 1:20. Examples of the N-vinylcarboxylic acid amide include N-vinylformamide and N-vinylacetamide, but N-vinylformamide is particularly preferable. Graft copolymerization is carried out in an aqueous medium in the presence of polyvinyl alcohol in a monomer solution state of N-vinylformamide and acrylonitrile, and water alone is preferable as the aqueous medium, but an organic solvent such as dimethyl sulfoxide or ethanol that is uniformly mixed with water is preferable. , N-methylpyrrolidone or the like may be mixed with water. As the polymerization method, a method of charging all the monomers in a polymerization container in the presence of polyvinyl alcohol to start the polymerization, or a method of charging a part of the monomers to the polymerization container and then charging the remaining monomers according to the progress of the polymerization after the polymerization is started, etc. Adopted. Hydrolysis is carried out under acidic conditions, and hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, sulfamic acid and the like can be mentioned as usable acids, but the use of hydrochloric acid is particularly preferable. When hydrolyzed in an alkaline atmosphere, the nitrile group turns into a carboxylate ion to form an anionic group, which is not a preferable method. The amount of acid used is 10 to 2 with respect to the formyl group of the side chain.
It is appropriately used in the range of 00 mol% depending on the target conversion rate. To prevent crosslinking during acid hydrolysis, it is advisable to add a hydroxylamine salt in an amount of 2 to 10 mol% based on the charged formyl group. The hydrolysis reaction is usually completed in 0.5 to 20 hours under the temperature condition of 40 to 120 ° C. The amidine group is produced by heating at a temperature condition of 80 to 120 ° C. for 0.5 to 20 hours to cause the amino group produced by the hydrolysis reaction of the formamide group and the adjacent nitrile group to undergo ring closure. Occurs. When the acrylonitrile copolymerization rate is 0%, an amidine group is not formed and the side chain is polyvinylamine (containing vinylformamide structural unit).

The saponification rate of polyvinyl alcohol can be arbitrarily selected from a partial saponification product of about 87 mol% to a complete saponification product of about 99 mol%, and a saponification product soluble in a polymerization solvent (aqueous medium). The degree of polymerization of polyvinyl alcohol can be arbitrarily selected depending on the purpose, from a low degree of polymerization (degree of polymerization of 300 to 700) to a high degree of polymerization (degree of polymerization of 1700 to 2400). Polyvinyl alcohol has a concentration of 2
It is placed in a polymerization field under the condition of 25% by weight in a solution (dispersed in some cases), and is allowed to exist in an aqueous medium at a monomer concentration of 5 to 60% by weight, and solution polymerization, reverse phase emulsion polymerization, reverse phase suspension polymerization, etc. By this, N-vinylcarboxylic acid amide or the like is graft-polymerized. Since oily substances are repelled as papermaking chemicals,
Solution polymerization (optionally precipitation polymerization) is preferably used.

According to the invention of claim 4, 10 to 100 mol% of N-vinylcarboxylic acid amide and 0 to 9 acrylonitrile in the presence of polyvinyl alcohol in an aqueous medium.
It is a papermaking agent having an intrinsic viscosity of 0.1 to 10 dl / g in a 1N saline solution obtained by copolymerizing a monomer containing 0 mol% and then hydrolyzing it. The range of 0.2 to 7 dl / g is preferably used as various papermaking agents according to the purpose. Conventionally known methods are used as they are as the paper-making chemicals.Low-molecular-weight coating chemicals and high-molecular-weight chemicals are used in fields requiring cohesive strength. As the enhancer, one having a medium molecular weight is applied.

A fifth aspect of the present invention relates to a paper strength enhancer as a specific use of the above paper-making chemical. Paper strength enhancers are used to improve the compressive strength, tensile strength, burst strength, surface strength, and interlaminar peel strength of paper.In addition to the method of adding them to pulp slurry during papermaking, they are also used for wet or dry paper rolls. A method of applying with a coater, size press, spray or dipping machine is also adopted. If necessary, a cationic starch, a general paper strengthening agent such as an anionic paper strengthening agent, a sulfuric acid band, or the like is used in combination. The type of pulp is not particularly limited, and GP, SP, KP, D
It is used for both IP and the like.

A sixth aspect of the present invention relates to a yield improving agent as a specific use of the above paper-making chemical. The product of the present invention is effective not only for improving the yield of the filler but also for improving the fixing yield of size, and has the effect of improving the water repellency of the paper.

The invention of claim 7 relates to a drainage improving agent as a specific use of the above paper-making chemical. The drainage improver is intended to improve the papermaking speed, is mainly used in paperboard, and is intended to increase the drying property by draining water on the wire and improving the water squeezing property.

The present invention of claim 8 relates to a surface coating agent for paper, which is a specific use of the above paper-making chemical.
The graft copolymer according to the present invention includes other coating agents such as cationic starch, oxidized starch, water-soluble polymer such as polyvinyl alcohol, latex or colloidal silica,
Coating pigments such as talc, kaolin clay and calcium carbonate can be used in combination. The amount added to these coating agents is usually 0.05 to 10 g / m ^{2 and} preferably 0.2 to
It is 5 g / m ² . The base paper to be coated is not particularly limited, and can be applied to each base paper such as acid paper, neutral paper, base paper, newsprint, PPC paper and the like. The coating solution prepared by mixing the graft copolymer according to the present invention with the coating base paper alone or in combination with other coating agents is applied to the surface by a size press, a gate roll coater, a blade coater or a calender, a printing paper, It can be a recording sheet.

A ninth aspect of the present invention relates to a surface coating agent for an adult paper as a specific use of the above-mentioned paper-making chemicals, which is characterized in that the product of the present invention is coated on the surface of a coated base paper. It is a method of manufacturing paper. The present invention not only improves the printability of coated base paper as described above,
As an inkjet recording paper, it binds to anionic water-soluble ink to make it water-insoluble, suppresses permeation into the paper, and retains a vivid color tone for color expression in inkjet printing.

[0015]

The product of the present invention comprises polyvinyl alcohol as a trunk polymer (main chain) and a vinylamine polymer unit or a vinylamidine polymer unit as a branch polymer (side chain) grafted thereto. Therefore, when it is used as a papermaking chemical, the hydroxyl groups of the trunk polymer are firmly bonded to the pulp by hydrogen bonds, and the amino groups of the branch polymer are
Amidine groups form ionic bonds with papermaking additives such as fillers and sizing agents. Further, when coated, it binds to the anionic water-soluble ink on the surface of the paper to make it water-insoluble, suppress the penetration into the paper, and maintain the vivid color tone of the printing ink. This is a characteristic not found in saponified products of polyvinyl acetate, polyvinyl amine, N-vinyl formamide and vinyl acetate copolymer.

[0016]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

(Synthesis Example 1) A 300 ml four-necked flask equipped with a stirrer, a nitrogen inlet tube, a condenser and a thermometer was charged with polyvinyl alcohol 117 manufactured by Kuraray Co., Ltd. (saponification rate: 98 to 99 mol%, degree of polymerization: 1700) 8.0 g and distilled water 127.0 g were charged and heated to 90 ° C. to dissolve polyvinyl alcohol. Next, after cooling to room temperature, 22.9 g (0.32 mol) of N-vinylformamide and 17.1 g (0.32 mol) of acrylonitrile were added, and then 8.0 g of a 1% 2-mercaptoethanol aqueous solution and 1% of hydroxylamine hydrochloride. 6.7 g of an aqueous solution was added.
In order to prevent evaporation of acrylonitrile, nitrogen gas was passed under ice-cooling, and then the temperature was raised to 50 ° C. to 2,2′-azobis-2.
-Amidinopropane dihydrochloride 2% aqueous solution 10.0 g was added and the mixture was kept at 50 ° C for 6 hours while stirring at 300 rpm. A part of the polymer was taken and added to acetone to precipitate a polymer, which was dried under vacuum to obtain a solid polymer. The degree of grafting onto polyvinyl alcohol was determined by NMR. Further, the amount of residual monomers was measured by liquid chromatography analysis to determine the polymerization rate. Next, 100 g of the above-mentioned polymer (liquid) was placed in a 200 ml three-necked flask equipped with a stirrer, a condenser and a thermometer, and 5.6 g and 35% of a 10% aqueous solution of hydroxylamine hydrochloride.
Hydrochloric acid 18.5 g (11 with respect to the formyl group in the copolymer)
(0 mol%) was added and reacted with stirring at 70 ° C. for 3 hours, then heated to 90 ° C. and hydrolyzed for 3 hours.
The obtained reaction product (hydrolyzate) solution was dropped into acetone to cause precipitation, and this was dried in vacuo to obtain a solid hydrolyzate. The colloid equivalent value and the intrinsic viscosity were measured by a conventional method. The results are shown in Table-1.

(Synthesis Examples 2 to 4) A hydrolyzed graft copolymer was obtained by the same operation as in Synthesis Example 1 except that the kind and amount of polyvinyl alcohol were changed. The results are summarized in Table 1.

(Comparative Example-1) After the same operation as in Synthesis Example-1 was carried out without using polyvinyl alcohol,
A sample was prepared by mixing the same amount of polyvinyl alcohol as in Synthesis Example-1. The results are shown in Table-1.

[0020]

[Table-1]

(Synthesis Example-5) 4.0 g of polyvinyl alcohol 117 (saponification rate 98-99 mol%, degree of polymerization 1700) and 146.0 g of distilled water manufactured by Kuraray Co., Ltd. were charged in the same apparatus as in Synthesis Example-1. After heating and dissolving in the same manner as in Synthesis Example-1, cooling to room temperature, adding 40.0 g of N-vinylformamide, passing nitrogen gas, and raising the temperature to 50 ° C, 2,2'-
10 g of a 2% aqueous solution of azobis-2-amidinopropane dihydrochloride was added, and the mixture was kept at 50 ° C. for 6 hours while stirring at 300 rpm to obtain a polymer. A part of the polymer was subjected to the same analytical operation as in Synthesis Example-1. Using 100 g of this polymer (liquid), 9.8 g of a 10% aqueous solution of hydroxylamine hydrochloride and 32.2 g of 35% hydrochloric acid were prepared in the same manner as in Synthesis Example-1.
(110 mol% with respect to the formyl group in the copolymer) was added and reacted with stirring at 70 ° C for 3 hours, then heated to 90 ° C and hydrolyzed for 3 hours. Table 2
Shown in

(Synthesis Examples 6 to 7) Hydrolysates were obtained in the same manner as in Synthesis Example 5 except that the amount of polyvinyl alcohol was changed by the same apparatus as in Synthesis Example-5. The results are shown in Table-2.

(Comparative Example-2) Synthesis-5 except that polyvinyl alcohol was not added in the same apparatus as in Synthesis Example-5.
A hydrolyzate was obtained by the same operation as in (1), and the same amount of polyvinyl alcohol as in Synthesis example 5 was added and mixed to obtain a sample.
The results are shown in Table-2.

Comparative Example 3 150.0 g of distilled water and 14 of Emulgen were placed in a 500 ml five-necked flask equipped with a stirrer, a nitrogen inlet tube, a monomer dropping funnel and a thermometer.
7 (Polyoxyethylene lauryl ether, Kao Corporation)
1.5 g) was added, and the mixture was heated to 65 ° C. On the other hand, in advance, 67.5 g of vinyl acetate (purity 99%), 45.0 g of N-vinylformamide and 2,2'-azobis- (2,2
A mixture of 0.25 g of 4-dimethylvaleronitrile) was placed in a monomer dropping funnel, and 17 g of the monomer mixture was added dropwise while passing nitrogen gas into the flask. After the polymerization started, the remaining monomer mixture was added dropwise over 1 hour,
Further, polymerization was carried out at 65 ° C. for 2 hours. Then distilled water 7
Dilute with 5 g and add a solution of 0.05 g of 2,2'-azobisisobutyronitrile in 3 ml of acetone to add 75
Polymerization was performed at a temperature of C for 2 hours, then a solution of 0.05 g of 2,2'-azobisisobutyronitrile dissolved in 3 ml of acetone was added, and the polymerization was performed at a temperature of 95 ° C for 1 hour. % And N-vinylformamide 45 mol%
A copolymer solution of the above copolymer was obtained. 230 mol% hydrochloric acid was added to this copolymer solution with respect to the formyl groups in the copolymer, and hydrolysis was carried out at 60 ° C. for 6 hours. The resulting hydrolyzate solution was poured into acetone to cause precipitation, and this was vacuum dried to obtain a solid copolymer hydrolyzate. The results are shown in Table-2.

[0025]

[Table-2]

(Synthesis Example 8) A 300 ml four-necked flask equipped with a stirrer, a nitrogen inlet tube, a condenser and a thermometer was charged with polyvinyl alcohol 117 manufactured by Kuraray Co., Ltd. (saponification rate: 98 to 99 mol%, degree of polymerization: 1700) 8.0 g and distilled water 148.0 g were charged and heated to 90 ° C. to dissolve polyvinyl alcohol. Then, after cooling to room temperature, 22.9 g (0.32 mol) of N-vinylformamide and 17.1 g (0.32 mol) of acrylonitrile were added, and 6.7 g of a 1% aqueous solution of hydroxylamine hydrochloride was added. In order to prevent evaporation of acrylonitrile, nitrogen gas was passed under ice cooling, and then the temperature was raised to 50 ° C. to obtain 2,2′-azobis-2-
Polymerization was carried out by adding 4.0 g of a 2% aqueous solution of amidinopropane dihydrochloride and maintaining the mixture at 45 ° C. for 15 hours while stirring at 300 rpm. A part of the polymer was taken and added to acetone to precipitate a polymer, which was dried under vacuum to obtain a solid polymer. The degree of grafting onto polyvinyl alcohol was determined by NMR. Further, the amount of residual monomers was measured by liquid chromatography analysis to determine the polymerization rate.
The polymerization rate was 99.8% and the grafting rate was 42%. Next, 100 g of the above polymer (liquid) was placed in a 200 ml three-necked flask equipped with a stirrer, a condenser and a thermometer, and a hydroxylamine hydrochloride 10% aqueous solution 5.6 was added.
g and 18.5 g of 35% hydrochloric acid (110 mol% based on the formyl group in the copolymer), and the mixture was stirred at 70
It was hydrolyzed at a temperature of C for 12 hours. The obtained reaction product (hydrolyzate) solution was dropped into acetone to cause precipitation, and this was dried in vacuo to obtain a solid hydrolyzate. The colloid equivalent value and the intrinsic viscosity were measured by a conventional method. Cation equivalent value is 6.0 meq / g and intrinsic viscosity is 5.3 dl / g
Met.

(Comparative Example 4) The same apparatus as in Example-8 was used, and the same polymerization operation as in Example-8 was carried out except that polyvinyl alcohol was not used. Then, the same amount of polyvinyl as in Example-8 was used. After mixing alcohol, the same hydrolysis and precipitation drying operations as in Example-8 were carried out to obtain a solid hydrolyzate. The cation equivalent value was 6.1 meq / g and the intrinsic viscosity was 5.0 dl / g.

(Synthesis example-9) Using the same apparatus as in synthesis example-1, 8.0 g of polyvinyl alcohol 117 (saponification rate 98-99 mol%, degree of polymerization 1700) manufactured by Kuraray Co., Ltd. and 150.0 g of distilled water were charged. After heating and dissolving in the same manner as in Synthesis Example-1, cooling to room temperature, adding 40.0 g of N-vinylformamide, passing nitrogen gas, and raising the temperature to 50 ° C, 2,2'-
Azobis-2-amidinopropane dihydrochloride 2% aqueous solution 2.0 g was added and the mixture was stirred at 300 rpm at 50 ° C. for 15 minutes.
It was kept for a time to obtain a polymer. A part of the polymer was taken and added to acetone to precipitate a polymer, which was dried under vacuum to obtain a solid polymer. The degree of grafting onto polyvinyl alcohol was determined by NMR. Further, the amount of residual monomers was measured by liquid chromatography analysis to determine the polymerization rate. The polymerization rate was 99.6% and the grafting rate was 30%. Next, 100 g of the above polymer (liquid) was placed in a 200 ml three-necked flask equipped with a stirrer, a cooler and a thermometer, and 5.8 g of a 10% aqueous solution of hydroxylamine hydrochloride and 11.7 g of 35% hydrochloric acid (formyl in the polymer). 40 mol% relative to the base) and added at 70 ° C to 12
Hydrolysis for hours. The obtained reaction product (hydrolyzate) solution was dropped into acetone to cause precipitation, and this was dried in vacuo to obtain a solid hydrolyzate. The colloid equivalent value and the intrinsic viscosity were measured by a conventional method. The cation equivalent value is 3.7.
It was meq / g and the intrinsic viscosity was 3.4 dl / g.

(Comparative Example 5) The same procedure as in Example-9 was carried out using the same apparatus as in Example-9, except that polyvinyl alcohol was not used, and then the same amount of polyvinyl as in Example-9 was used. After mixing alcohol, the same hydrolysis and precipitation drying operations as in Example-9 were carried out to obtain a solid hydrolyzate. The cation equivalent value was 3.8 meq / g and the intrinsic viscosity was 3.2 dl / g.

[Effect test-1] 5 ml of 300 ml of LBKP [CSF (Canadian Standard Freeness) = 400 ml] pulp slurry (pulp concentration 0.4%) was added.
In a 00 ml glass beaker, 0.3% emulsion rosin size to pulp, 0.2% polymer to pulp of this example, and 3% liquid band to pulp of this example were added and mixed at an interval of 20 seconds while stirring at 600 rpm. ,
Target paper weight of 60 with Tappy Standard handmade paper machine
g / m ² paper, roll-dried at 105 ° C. for 5 minutes, and then conditioned in a constant temperature and humidity room at a temperature of 20 ° C. and a humidity of 60%.
Burst strength and Stekigt sizing degree were measured. The bursting strength was based on JIS P-8112, and the Stechig sizing degree was based on JISP-8122. The results are shown in Table-3.

[0031]

[Table-3]

[Effect Test-2] Polymer of this Example 1.
A 2% aqueous solution was prepared, and this was mixed with a commercially available medium paper (basis weight 55 g /
m ² , manufactured by Daishowa Paper Co., Ltd.) using a coating rod and roll-dried at 105 ° C. for 5 minutes to obtain a coated paper. The coating amount is 0.1 g / m ² and 0.2 g / m ²
It is. Table 4 shows the results of the burst strength test.

[0033]

[Table-4]

[Effect test-3] LBKP of effect test-1
Then, 1000 ml of a 0.3% slurry was added, and 2% of the liquid band was added to the pulp while stirring at 300 rpm. After 20 seconds, the polymer of the present example was added in the indicated amount. After stirring for 20 seconds, the mixture was charged into a Canadian Standard Freeness Tester. The amount of drainage was measured. The results are shown in Table-5.

[0035]

[Table-5]

[Effect test-4] A coating solution (6.8 g of finely powdered silica, PVA117 (manufactured by Kuraray) was used with a high-quality paper having a basis weight of 70 g / m ² and a Steckigt size of 25 seconds as a support.
2.7 g, 0.5 g of the polymer of this example and 40 g of water
5.0 g / m ² in solid content was coated on one surface with a coating rod to obtain a coated paper. After color printing of this coated paper, the water resistance and lightfastness of the print were measured as follows. Color printing is provided by Canon Inc.
Solid printing was performed for each color of magenta (M), cyan (C), yellow (Y), and black (BL) using a color bubble jet printer manufactured by BJC600. The results are shown in Table-6. (Water resistance) The solid printed image was immersed in running water of 3 liter / min for 10 minutes, and the image density before and after the test was evaluated on a 5-point scale. <Judgment> A: No change B: Color slightly exudes. C: Discoloration is recognized. D: Large discoloration. E: Almost decolorized. (Light fastness) The solid printed image is 24
Irradiation was performed for a period of time, and the image density before and after the irradiation was evaluated in four stages. <Judgment> A: No change B: Slight fading. C: Fading. D: Extremely fading.

[0037]

[Table-6]

[0038]

The papermaking agent of the present invention is a random copolymer with vinyl alcohol as a polymer such as vinylamine,
Or unlike a mixture with polyvinyl alcohol,
It has excellent properties as a papermaking chemical. It was unexpected that no one could obtain such a papermaking agent having such excellent properties by such an easy method, and therefore the value of the present invention is high.

Claims (9)

[Claims] 1. N-vinylcarboxylic acid amide 10-100 in the presence of polyvinyl alcohol in an aqueous medium.
A papermaking agent obtained by copolymerizing a monomer containing mol% and 0-90 mol% of acrylonitrile, and then hydrolyzing it. 2. N-vinylcarboxylic acid amide 35-100 in the presence of polyvinyl alcohol in an aqueous medium.
The papermaking chemical according to claim 1, which is obtained by copolymerizing a monomer containing mol% and acrylonitrile in an amount of 0 to 65 mol% and then hydrolyzing the monomer. 3. When a monomer is copolymerized in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzed to produce a polymer, the formula weight ratio of polyvinyl alcohol and the monomer is 2: 1 to 1:20. The papermaking chemical according to claim 1 or 2, characterized in that: 4. A polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the polymer, wherein the intrinsic viscosity in 1N saline is 0.1 to 10 dl / g. The papermaking chemical according to claim 1 to claim 3. 5. The paper strengthening agent according to claim 1, wherein a polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the same is used. . 6. The yield improver according to claim 1, wherein a polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the monomer is used. 7. The drainage improver according to claim 1, wherein a polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the monomer is used. . 8. The surface of the paper according to claim 1, wherein a polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the monomer is used. Coating agent. 9. The surface of the paper according to claim 1, wherein a polymer obtained by copolymerizing a monomer in the presence of polyvinyl alcohol in an aqueous medium and then hydrolyzing the same is used. A method for producing an inkjet recording paper, which comprises applying a coating agent to the surface of a base paper to be coated.