JPH11217792A - Additive for papermaking and papermaking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an additive for papermaking, capable of manifesting activities for improving a yield and a paper strength within a wide pH region by adding a twitterionic acrylamide-based copolymer consisting essentially of a primary alkenylamine and/or a salts thereof to a pulp slurry as the additive. SOLUTION: This additive for papermaking of a twitterionic acrylamide-based copolymer is obtained by polymerizing a vinyl monomer mixture comprising 0.01-20 mol.% primary alkenylamine and/or salts thereof, e.g. 2-propene-1-amine, 40-98.99 mol.% acrylamides, 0.5-20 mol.% anionic vinyl monomer such as acrylic acid and 0.5-20 mol.% cationic vinyl monomer such as diethylaminoethyl acrylate. The additive for the papermaking of 0.01-10 wt.%, preferably 0.03-3 wt.% based on the bone-dried solid component of the pulp is added to the pulp slurry and the pulp slurry with the added additive is subjected to the papermaking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a papermaking additive comprising a zwitterionic acrylamide copolymer used in a papermaking process and a papermaking method. More specifically,
The present invention relates to a novel papermaking additive and a papermaking method exhibiting excellent drainage, retention and paper strength enhancing effects even under papermaking conditions in a wide pH range from acidic to neutral to alkaline.

[0002]

2. Description of the Related Art In the papermaking process of paper and paperboard, the utilization rate of waste paper is increased due to factors such as the deterioration of raw wood supply and energy saving, and the papermaking system is being closed. The importance of paper strength agents, drainage improvers and retention aids has increased, and these various papermaking additives have been provided.

As additives for papermaking, starches, polyamide polyamine-epichlorohydrin resins, polyacrylamide resins and the like are widely used, and in particular, the use of polyacrylamide resins is expanding. The types of papermaking additives composed of polyacrylamide resins are largely classified into anionic polymers, cationic polymers and zwitterionic polymers due to their ionic differences. Among these, recent deterioration of papermaking raw materials, improvement of papermaking speed, etc.
Even under severe papermaking conditions, the amphoteric copolymer obtained by copolymerizing an anionic vinyl monomer and a cationic vinyl monomer with (meth) acrylamide has a relatively small decrease in the effect, and the use ratio has been increasing. However, even these linear type polymers are insufficient for meeting the above-mentioned demands for high quality and deterioration of papermaking conditions.

Recently, when preparing (meth) acrylamide, a cationic vinyl monomer and an anionic vinyl monomer to prepare an acrylamide copolymer,
An acrylamide copolymer having a branched structure having a relatively high molecular weight and having a bifunctional, trifunctional or tetrafunctional crosslinkable vinyl monomer introduced into the copolymer chain has attracted attention. That is, the acrylamide-based copolymer having the above structure,
It is said that an excellent paper strength effect can be obtained in a wide pH range, and many proposals have been made in this regard. (For example, JP-A-63-50597, JP-A-2-611)
No. 97, JP-A-4-18190, JP-A-3-3190
No. 227482, Japanese Unexamined Patent Publication No. 3-227483, Japanese Unexamined Patent Publication No. 5-14089, etc.)

However, if the amount of the crosslinkable vinyl monomer in the vinyl monomer constituting the copolymer is too large, gelation occurs locally, and the copolymer is insoluble in water. In practice, the amount of the crosslinkable vinyl monomer used is limited to 1 mol% or less in order to solve the above-mentioned disadvantage. For this reason, the introduction of a branched structure that plays an important role in imparting excellent properties to paper quality is limited. In Japanese Patent Application Laid-Open No. 2-8207, a small amount of a reactive surfactant is It proposes a method for preventing uniform gelation and obtaining a uniform aqueous solution. JP-A-7-9779 proposes that a specific N-substituted (meth) acrylamide is used to introduce a large number of branched structures into a polymer.
However, this method is still insufficient to solve the above-mentioned disadvantage.

[0006]

[Problems to be Solved] As is well known, in the paper making process of paper and paperboard, as described above, energy saving and resource saving are strongly demanded for paper raw materials due to environmental problems. Respond to severe papermaking conditions, such as an increase in the rate of papermaking, a decrease in the yield of fine fibers, fillers, and internal chemicals due to the closure of the papermaking process due to wastewater regulations, a speeding up of the papermaking machine to improve productivity, and a decrease in quality. There is an increasing demand for improvements or quality improvements accompanying the diversification of paper. However, conventional papermaking additives have not been sufficient to solve these problems. That is, there is a strong demand for papermaking additives that exhibit excellent drainage, retention and paper strength enhancing effects.

The present inventors have conducted intensive studies to solve the above-mentioned problems and to solve the disadvantages of the prior art. As a result, primary alkenylamines and / or salts thereof have a branching / crosslinking ability, It has been found that a papermaking additive containing a zwitterionic acrylamide-based copolymer and / or a salt thereof as an essential component exhibits excellent drainage, retention and paper strength enhancing effects.

[0008]

SUMMARY OF THE INVENTION To summarize the present invention, a first aspect of the present invention is a papermaking machine containing a zwitterionic acrylamide copolymer containing a primary alkenylamine and / or a salt thereof as an essential component. It is an additive. A second aspect of the present invention is a papermaking method in which the papermaking additive of the present invention is added to a pulp slurry to make paper.

As described above, the present invention relates to a papermaking additive comprising a zwitterionic acrylamide copolymer containing a primary alkenylamine and / or a salt thereof as an essential component,
A novel papermaking additive and a papermaking method that exhibit excellent drainage, retention and paper strength enhancing effects even under severe papermaking conditions in a wide pH range. That is, the present invention polymerizes a vinyl monomer mixture comprising a primary alkenylamine and / or a salt thereof (a), an acrylamide (b), an anionic vinyl monomer (c), and a cationic vinyl monomer (d). Is an amphoteric acrylamide copolymer obtained by the above method. More preferably, primary alkenylamine and / or its salt (a) 0.01 to 20 mol%,
A vinyl monomer mixture containing 40 to 99.99 mol% of acrylamides (b), 0.5 to 20 mol% of anionic vinyl monomer (c), and 0.5 to 20 mol% of cationic vinyl monomer (d) Is an amphoteric acrylamide-based copolymer obtained by polymerizing the above.

The alkenylamine and / or its salt (a) used in the amphoteric acrylamide copolymer of the present invention include 2-propen-1-amine and 2-propen-1-amine.
Methyl-2-propen-1-amine, 2-ethyl-2-
Propen-1-amine, etc. or their hydrochloric acid, sulfuric acid,
Phosphoric acid, sulfamic acid, acetic acid, propionic acid, lactic acid, citric acid, malic acid, salts of inorganic acids or organic acids such as succinic acid, and the like.One kind of these may be used alone, or two or more kinds. May be used in combination.

The acrylamides (b) used in the amphoteric acrylamide copolymer of the present invention include, for example, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N- Isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, diacetone (meth) acrylamide, and the like can be mentioned. They may be used, or two or more kinds may be used in combination. It is desirable to use acrylamide as a main component from the viewpoint of cost performance.

The anionic vinyl monomer (c) used in the amphoteric acrylamide copolymer of the present invention
Examples thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, itaconic acid, maleic acid, fumaric acid, muconic acid, citraconic acid, and mesaconic acid, and alkali metal salts and alkaline earth salts thereof. Examples thereof include metal salts and ammonium salts. These may be used alone or in combination of two or more.

The cationic vinyl monomer (d) used in the amphoteric acrylamide copolymer of the present invention
Examples thereof include (meth) acrylate derivatives such as diethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate; dimethylaminopropyl (meth) (Meth) acrylamide derivatives such as acrylamide, or their hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid,
Examples thereof include inorganic acids and organic acids such as sulfamic acid, acetic acid, propionic acid, lactic acid, citric acid, malic acid, and succinic acid. Also, a quaternary ammonium salt vinyl monomer obtained by quaternizing the tertiary amino group of these vinyl monomers with an alkyl halide, phenylalkyl halide, dialkyl sulfate, epichlorohydrin, chloroacetic acid, etc., for example, (meth) acryloyloxyethyltrimethylammonium chloride , (Meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth)
Acryloyloxyethyltrimethylammonium methyl sulfate can be exemplified. Other examples include diallyldimethylammonium chloride and 3- (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride. Then, one of these may be used alone, or two or more thereof may be used in combination.

In the present invention, besides the above-mentioned constituent vinyl monomer, a vinyl monomer copolymerizable with the above-mentioned constituent vinyl monomer can be used as long as the effects of the present invention are not substantially impaired. Examples of this type of copolymerizable vinyl monomer include acrylonitrile, vinyl acetate, styrene, α-methylstyrene, alkyl (meth) acrylates, N-vinylpyrrolidone, N-vinylformamide, and N-vinylcaprolactam. Nonionic vinyl monomers, reactive monomers such as glycidyl (meth) acrylate, methylol (meth) acrylamide, methoxymethyl (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, divinylbenzene, divinyl adipate,
Ethylene glycol di (meth) acrylate, 1,3
Examples thereof include polyfunctional vinyl monomers such as 5-triacryloylhexahydro-1,3,5-triazine and triallylisocyanurate.

In the amphoteric acrylamide copolymer of the present invention, the molar ratio of the components (a) to (d) is as follows:
(A) component 0.01 to 20 mol%, (b) component 40 to 9
8.99 mol%, component (c), 0.5 to 20 mol%,
(D) Component is in the range of 0.5 to 20 mol%. Preferably, 0.1 to 10 mol% of component (a), 70 to 9 of component (b)
7.9 mol% (c) component 1 to 10 mol% (d) component 1
10 mol%. If (a) is less than 0.01 mol%, a polymer having a sufficient branched structure cannot be obtained, and if it exceeds 20 mol%, the obtained copolymer gels and becomes water-insoluble. However, the papermaking additive of the present invention cannot be obtained. When the proportions of the components (b), (c) and (d) are out of the above ranges, the object of the present invention cannot be achieved.

The components (a), (b), (c) and (d) for producing the papermaking additive according to the present invention are optimally determined in consideration of the type of paper to be produced, papermaking conditions and the like. Used at the rate of use.

The production of the papermaking additive according to the present invention can be carried out by a conventionally known method. For example, the components (a) to (d), water and, if necessary, a chain transfer agent are charged into a reaction vessel so that the monomer concentration at the time of charging is usually 5 to 30% by weight, and the radical polymerization initiator is stirred. , And the mixture is heated to carry out polymerization to obtain the papermaking additive according to the present invention. The form of the polymerization reaction may be either a batch reaction or a semi-batch reaction. The reaction temperature is usually 50 to 90 ° C, and the reaction time is about 1 to 5 hours. Examples of the radical polymerization initiator include persulfates such as ammonium persulfate and potassium persulfate, peroxides such as hydrogen peroxide and benzoyl peroxide, 2,2-azohis (2-amidinopropane) hydrochloride, and azobisisopropane. Examples thereof include azo compounds such as butyronitrile, and these may be used alone or in combination of two or more. When an oxidizing substance such as a persulfate or a chemical oxide is used as an initiator, redox polymerization can be performed in combination with a reducing agent. Here, examples of the reducing agent include sulfites such as sodium sulfite, and bisulfites such as sodium bisulfite. The chain transfer agent used here may be a known one, for example, thiols such as mercaptan, thioglycolic acid and its esters, allyl alcohol, sodium allyl sulfonate,
Examples thereof include (meth) allyl compounds such as sodium methallylsulfonate, alcohols such as isopropyl alcohol, and phosphinates such as sodium phosphinate. It is also possible to add a polymerization initiator several times in order to reduce the residual monomer.

The papermaking additive according to the present invention is generally added to a wet end portion of pulp slurry or wet paper in the papermaking process of paper and paperboard. The addition ratio is 0.01 to 10% by weight, preferably 0.03 to 3% by weight, based on the solid content of the pulp.
It is. The pH of the pulp slurry or wet paper at the time of addition is 4 to 8. As the type of pulp, various pulp such as chemical pulp, mechanical pulp, corrugated cardboard pulp, magazine pulp or newspaper pulp, or non-cellulose fiber such as glass wool or chemical fiber can be used. Other dyes, contents, fillers,
A pH adjusting agent such as sulfuric acid or sodium hydroxide, a sizing agent, a wet paper strength improver, a dry paper strength enhancer, a drainage improver, a retention improver, an antifoaming agent or a slime control agent can be used in combination. Further, it can be used for any neutral to acidic paper making, for example, high quality paper, medium paper, coated paper, newsprint, processed base paper, liner, corrugated paper such as core base paper, PPC paper, inkjet paper, It can be used for thermal paper, special paper, toner printer paper, gypsum board paper, building material paper, etc.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention are as follows.

[Preparation of Papermaking Additives] Thermometer, stirrer,
In a reaction flask equipped with a cooling pipe and a nitrogen gas inlet pipe, vinyl monomer components such as 2-propen-1-amine, 50% acrylamide solution, dimethylaminoethyl methacrylate, and itaconic acid, and allyl as a predetermined amount of chain transfer agent Charge sodium sulfonate and water, adjust the pH to 20% with an aqueous sulfuric acid solution, raise the temperature to 55 ° C. under nitrogen gas introduction, and then add a 50% aqueous ammonium persulfate solution and a 5% aqueous sodium bisulfite solution as polymerization initiators. A fixed amount is added, and a polymerization reaction is performed at 80 ° C. for 2 hours to obtain an amphoteric acrylamide copolymer.

[Evaluation Method of Paper Quality] A sulfuric acid band was added to a pulp slurry having a concentration of 3% of corrugated paper (CSF 370 ml) having a concentration of pulp of 1.5% to a pH of 5.8. Next, the zwitterionic acrylamide-based copolymer was added to pulp solid content of 0.5%, and the obtained pulp slurry was made into a paper having a basis weight of 150 g / m ² by a TAPPI standard sheet machine, and pressed with a press pressure. 5kg / cm
² for 5 minutes and dried on a hot plate at 110 ° C. for 3 minutes to prepare a test paper. Test paper temperature 20 ℃, humidity 65%
After conditioning for 24 hours under the above conditions, a test is conducted by the following paper quality evaluation method.

(1) Paper quality evaluation method Compressive strength: JIS P8126 Burst strength: JIS P8112 Tensile strength: JIS P8113

[Drainage test method] A corrugated paperboard pulp slurry having a concentration of 3% containing a chemical was prepared in the same manner as in the papermaking conditions in the above paper quality evaluation method. Diluted to 10%
The measurement was carried out using a Canadian freeness tester according to JIS P8121 using 0 ml.

[Retention Effect Test Method] A cardboard corrugated paper pulp slurry having a concentration of 3% to which a chemical was added was prepared in the same manner as in the papermaking conditions in the paper quality evaluation method, and the slurry was prepared by adding water to the same pH as the pulp slurry. %, And 500 ml of the diluted solution was added to TAPPI JOURNAL 56 (1
0) dynamics described in 46 to 50 (1973)
PAPER of device similar to drainage jar
RESEARCH MATERIALS, INC B
pour into rit Jar Tester, 70 for 20 seconds
After stirring at 0 rpm, the mixture was drained for 10 seconds.
Collect 00 ml. The filtrate was no. The solution was filtered through filter paper No. 3, and the value of the first pass retention was determined from the amount of the residue.

[0025]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. All percentages are by weight unless otherwise specified.

Example 1 162 g (91.5 mol) of a 50% aqueous acrylamide solution was placed in a 500 ml four-necked flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen gas inlet tube.
%), 9.80 g of dimethylaminomethyl methacrylate
(5 mol%), 4.06 g of itaconic acid (2.5 mol%)
%), 2-propen-1-amine 0.721 g (1 mo
1%), 3% aqueous solution of sodium methallylsulfonate 18
g, 310 g of water and 13.8 g of a 20% aqueous sulfuric acid solution to adjust the pH to 4.0, the temperature was raised to 55 ° C. under nitrogen gas introduction, and 2.88 ml of a 5% aqueous ammonium persulfate solution
And 0.72 ml of a 5% aqueous sodium bisulfite solution were added, and reacted at 80 ° C. for 2 hours to obtain an amphoteric acrylamide copolymer A. Table 1 shows the properties of the polymer.

[Examples 2 to 7] In Example 1, the type of vinyl monomer component or its monomer composition (mol%)
Was changed as shown in Table 1, and zwitterionic acrylamide copolymers B to G were obtained in the same manner as in the examples. Table 1 shows the properties of the copolymer.

[Comparative Examples 1 to 5] An acrylamide copolymer was prepared in the same manner as in Example 1 except that the type of the vinyl monomer component or the monomer composition (mol%) was changed as shown in Table 1. Polymers HM were obtained. The properties are shown in Table 1.

The meanings of the abbreviations used in Table 1 are as follows. AAM: acrylamide MAAm: methacrylamide DMAA: dimethylacrylamide DM: dimethylaminoethyl methacrylate DMB: methacryloyloxyethyl dimethylbenzylammonium chloride DMC: methacryloyloxyethyltrimethylammonium chloride IA: itaconic acid AA: acrylic acid AAn: 2-propene-1- Amine MBA: methylenebisacrylamide TAF: 1,3,5-triacylhexahydro-
1,3,5-triazine MMA: methyl methacrylate St: styrene

[0030]

[Table 1]

[Application Examples 1 to 7 and Comparative Application Examples 1 to 5]
Cardboard waste paper is beaten with a Niagara beater and the Canadian Standard Freeness (CSF) 3
A sulfuric acid band was added to 1.5% by weight of pulp to a 3% by weight waste paper pulp slurry adjusted to 70 ml to adjust the pH to 5.8. The copolymers obtained in the above Examples 1 to 7 and Comparative Example were added at a solid content of 0.5 wt% based on pulp, and the obtained pulp slurry liquid was equivalent to a basis weight of 150 g / m ² using a TAPPI standard sheet machine. Was pressed at 5 kg / m ² for 5 minutes, and dried on a hot plate at 110 ° C. for 3 minutes to prepare a test paper. After conditioning for 24 hours at a temperature of 20 ° C. and a humidity of 65%,
Compressive strength, burst strength and tensile strength were measured according to IS P8126, P8112 and P8113. Table 2 shows the results. In addition, the measurement of drainage and the retention effect was performed according to the following. Table 2 shows the results.

[Drainage test] Concentration 3 to which chemicals were added in the same manner as in the papermaking conditions in Application Examples 1 to 7 and Comparative Examples 1 to 5
% Paperboard pulp slurry was prepared, diluted with tap water adjusted to the same pH as the pulp slurry to 0.3%, and 100 ml thereof was measured with a Canadian freeness tester according to JIS P8121.

[Yield Effect Test] A 3% -concentrated corrugated paper pulp slurry containing a chemical was prepared in the same manner as in the papermaking conditions in Application Examples 1 to 7 and Comparative Examples 1 to 5, and was adjusted to the same pH as the pulp slurry. Diluted to 0.6% with water, and 500 ml of TAPPI JOURNAL
56 (10) 46-50 (OCT.1973), a PAPER RESEARCH MATERIAL of an apparatus similar to the dynamic drain jar.
S, INC. Pour into a Brit Jar Tester manufactured by INC and stir at 700 rpm for 20 seconds, then drain for 10 seconds, then collect 100 ml of filtrate. The filtrate is
o. The solution was filtered through filter paper No. 3, and the value of the first pass retention was determined from the amount of the residue.

[0034]

[Table 2]

[0035]

According to the present invention, the additive for papermaking comprising a zwitterionic acrylamide copolymer prepared by using the primary alkenylamine and / or salts thereof as an essential component is:
As is evident from the results shown in Table 2, it is clear that, compared to the conventional papermaking additives, it shows excellent effects in drainage, retention, and paper strength in a wide pH range.

Claims (5)

[Claims] 1. A papermaking additive comprising a zwitterionic acrylamide-based copolymer containing a primary alkenylamine and / or a salt thereof (a) as an essential component. 2. An amphoteric acrylamide-based copolymer,
Zwitterionic polymer obtained by polymerizing a vinyl monomer mixture containing primary alkenylamine and / or salts thereof (a), acrylamides (b), anionic vinyl monomer (c) and cationic vinyl monomer (d) The papermaking additive according to claim 1, which is an acrylamide-based copolymer. 3. The papermaking additive according to claim 1, wherein at least one of the primary alkenylamine and / or its salt (a) is 2-propen-1-amine. 4. An amphoteric acrylamide-based copolymer,
Primary alkenylamine and / or its salt (a) 0.0
1 to 20 mol%, acrylamides (b) 40 to 98.
99 mol%, anionic vinyl monomer (c) 0.5 to
20 mol%, cationic vinyl monomer (d) 0.5 to
4. The papermaking additive according to claim 1, which is a zwitterionic acrylamide copolymer obtained by polymerizing a vinyl monomer mixture containing 20 mol%. 5. A papermaking method characterized by adding the papermaking additive according to any one of claims 1, 2, 3 and 4 to a pulp slurry and papermaking.