KR20160042171A - Intermediate for papermaking additive, and method for manufacturing papermaking additive - Google Patents

Abstract

The present invention relates to a process for producing an additive for paper and an additive for papermaking which gives a papermaking additive excellent in balance of the effect of improving the yield and the effect of improving the freeness.
The acrylamide polymer contained in the intermediate of the papermaking additive has an intrinsic viscosity of 12.5 to 28 dl / g and an anionization degree of 0.05 meq / g or less, and in the polymerization reaction step of producing an acrylamide polymer contained in the intermediate, And the method for producing a papermaking additive has a step of adding an intermediate of this papermaking additive to a Hoffman decomposition reaction.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing an intermediate for papermaking additives and a method for producing papermaking additives,

The present invention relates to a process for the preparation of papermaking additives characterized in that the papermaking additive intermediate comprising a polyacrylamide polymer and its intermediates are added to the Hoffman degradation reaction.

In recent years, various papermaking additives have been used to improve the yield and freeness in the papermaking process. For example, a cationic copolymer (C-PAM) of dimethylaminoethyl (meth) acrylate (DAA) and acrylamide (AAM) is mainly used as a yield improving agent. In addition, polyethyleneimine and polyvinylamine are mainly used as an improvement agent for water quality.

The DAA-PAM-based yield improving agent has a large molecular weight, but the cationic group of the DAA is distant from the main chain. Therefore, the effect of improving the yield was remarkable, but there was a problem that the flocs of the paper were large and frequent collapsed to cause defective dewatering.

Polyethylenimine or polyvinylamine has a high effect of improving the degree of freeness. However, since it has a small molecular weight, it needs to be used in a large amount, and there is a problem that the yield improving effect is insufficient. Particularly, the polyethyleneimine is too strong in cationicity, so that it can not exhibit its effect unless it is added in a large amount, and polyvinylamine has a problem that it is difficult to put it into practical use because of its high price.

Hoffman reaction has been developed for paper additives, but it was mainly used for the purpose of strengthening the intellect. In addition, Hoffmann reaction can not obtain sufficient diffusion of the molecular structure, and since the flocs are weak, there is a problem that a sufficient yield improving effect and an improvement in the water fineness can not be obtained (see Patent Document 1).

Patent Document 1: Japanese Patent Publication No. 2907498

Such a papermaking additive has a high effect in a part of properties from the viewpoints of a yield improvement effect and a freeness improvement effect but does not have a sufficient effect in all of these properties and has a poor balance as a papermaking additive.

It is an object of the present invention to provide a method for producing an additive for papermaking and an additive for papermaking which gives a papermaking additive having an excellent balance between the effect of improving the yield and the effect of improving the freeness.

The inventors of the present invention have found that the papermaking additives obtained by adding an intermediate of a papermaking additive containing a predetermined acrylamide polymer to a Hoffman decomposition reaction have a balance of a yield improving effect and a freeness improvement effect, . Specifically, the present invention provides the following.

(1) An intermediate of a papermaking additive comprising an acrylamide polymer having an intrinsic viscosity of 12.5 to 28 dl / g and an anionization degree of 0.05 meq / g or less.

(2) An intermediate of the papermaking additive according to (1), wherein in the polymerization reaction step of producing the acrylamide-based polymer, the crosslinking agent is not added.

(3) A process for producing a papermaking additive comprising a step of adding an intermediate of a papermaking additive according to (1) or (2) to a Hoffman decomposition reaction.

(4) A process for producing a papermaking additive according to (3), wherein in the Hoffman decomposition reaction, the acrylamide polymer is provided in the reaction as a solution of 2 mass% or less.

According to the present invention, it is possible to provide a novel papermaking additive having a balance of the yield improvement effect and the freeness improvement effect.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

<Intermediate of papermaking additive>

An intermediate of the papermaking additive in the present invention includes an acrylamide-based polymer having an intrinsic viscosity (measured at 30 ° C in a 1N-NaNO ₃ aqueous solution) of 12.5 to 28 dl / g and an anionization degree of 0.05 meq / g or less . By having an intrinsic viscosity and an anionization degree in the above-mentioned numerical range, the papermaking additive can have a satisfactory effect in balance in terms of improvement of yield and improvement of freeness.

The inherent viscosity and molecular weight of the acrylamide-based polymer generally have a correlation. That is, when the intrinsic viscosity is lowered, the molecular weight is lowered, and the degree of freeness and yield are lowered. Therefore, in order to improve the freeness and the yield, the intrinsic viscosity of the acrylamide-based polymer should be 12.5 dl / g or more. The intrinsic viscosity of the acrylamide polymer is more preferably 13.0 dl / g or more, still more preferably 14.0 dl / g or more, and most preferably 14.5 dl / g or more. Also, if the intrinsic viscosity of the acrylamide polymer is too high, the molecular weight becomes too large and acts as a flocculant when added in the papermaking process, resulting in the collapse of the paper texture. Therefore, in order to prevent agglomeration, the intrinsic viscosity of the acrylamide-based polymer needs to be 28 dl / g or less. The intrinsic viscosity of the acrylamide polymer is more preferably not more than 24 dl / g, more preferably not more than 20 dl / g, most preferably not more than 16 dl / g. In addition, the intrinsic viscosity is measured by measuring the flow time using a Cannon-Fenske viscometer and calculating from the measured values using the Huggins equation and the Mead-Fuoss equation.

If the degree of anionization of the acrylamide-based polymer is too high, the yield of the polymer decreases due to the ionic reaction between the cationic group and the anionic group in the acrylamide-based polymer molecule. Therefore, the degree of anionization of the acrylamide polymer for improving the yield is preferably 0.05 meq / g or less, more preferably 0.04 meq / g or less, still more preferably 0.03 meq / g or less, and most preferably, Is not more than 0.01 meq / g.

The anionization degree is expressed by a colloid equivalent value, and the colloid equivalence value is carried out by the following method, as described in paragraph [0029] of Japanese Patent Application Laid-Open No. 2009-228162.

[Method for Measuring Colloidal Equivalent Value]

An anionic polymer compound diluted in 50ppm aqueous solution (diluted with pure water) is taken in a 100ml measuring cylinder and transferred to a 200ml beaker. 0.5 ml of a 2N sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) was added to the mixture with a whole pipette while stirring the mixture, followed by stirring with a N / 200 methyl glycol chitosan solution (Manufactured by Wako Pure Chemical Industries, Ltd.) is added with a hole pipette. 2 to 3 drops of a toluidine blue indicator (manufactured by Wako Pure Chemical Industries, Ltd.) are added, and the mixture is titrated with N / 400 polyvinyl alcohol potassium sulfate solution (manufactured by Wako Pure Chemical Industries, Ltd.). The point where the red color changes to red color and the red color does not disappear even after a few seconds is set as the end point. A blank test (blank test) is similarly carried out with pure water.

Colloidal equivalent value (meq / g) = [measured value (ml) of anionic polymer compound - titration amount (ml) of blank test) / 2

The higher freeness is particularly noticeable in the paper making system where aluminum sulfate is not used. In addition, this means that the papermaking machine can drain well, and the dehydration of the press is good due to the formation of the tightly packed flock, leading to a reduction in the consumption of steam in the drying section. That is, the present invention also has a feature of high press dehydration property.

High press dewaterability means that the water content of the wet paper at the press inlet is reduced and the occurrence of cracking is suppressed. In addition, since the conventional papermaking machine is an obstacle to the papermaking speed of the machine, the steam consumption leads to a speed increase of the machine.

The present invention is remarkably improved in yield compared to polyethyleneimine, and is superior in paper force to polyethylenimine and polyvinylamine.

Paper additives refer to those used as additives in the paper making process, and they are mainly used for the purpose of improving yield, improving water retention, or improving paper strength. However, the present invention is not limited to these objects, and can be appropriately selected according to the purpose.

The papermaking additive intermediate is an acrylamide polymer that becomes a precursor of the papermaking additive. More specifically, it means an acrylamide-based polymer intended to be provided in the Hoffman decomposition reaction.

The acrylamide-based polymer means a polymer obtained by polymerizing acrylamide, and may contain other cationic monomers. In addition, the anionic monomer may or may not be included, but the acrylamide polymer obtained by the polymerization reaction needs to have an intrinsic viscosity of 12.5 to 28 dl / g and an anionization degree of 0.05 meq / g or less. However, in order to improve the yield by lowering the anionization degree and suppressing the hydrolysis of the acrylamide-based polymer at the time of polymerization, it is preferable not to include the anionic monomer.

The acrylamide-based polymer is preferably a linear polymer (linear polymer) in order to further improve the yield and yield of the papermaking additive. That is, as the monomer other than the acrylamide used in the polymerization reaction of the acrylamide-based polymer, it is preferable that the crosslinking monomer is not polymerized.

Examples of the crosslinkable monomer include methylene bisacrylamide, hexamethylene bisacrylamide, N, N-diallylacrylamide trimethylolpropane triacrylate, methylol acrylamide and N-methoxymethylacrylamide.

As the solvent used in the polymerization reaction of the acrylamide polymer, for example, water, alcohol, dimethylformamide and the like can be used. Water is preferable considering cost.

The polymerization initiator of the acrylamide-based polymer is not particularly limited as long as it is soluble in a solvent. Azo compounds such as 2, 2'-azobis-2-amidinopropane hydrochloride, azobisisobutyronitrile, and 2, 2'-azobis-2,4-dimethylvaleronitrile have. Examples of peroxide compounds such as ammonium persulfate, potassium persulfate, hydrogen peroxide, ammonium peroxosulfate, benzoyl peroxide, lauroyl peroxide, succinic peroxide, octanoyl peroxide and t-butyl peroxy 2-ethylhexanoate . Further, a redox system in which ammonium peroxosulfate is combined with sodium sulfite, sodium hydrogensulfite, tetramethylethylenediamine, trimethylamine, or the like can be given.

The temperature and time for the polymerization reaction of the acrylamide polymer are not particularly limited as long as the obtained acrylamide polymer has an intrinsic viscosity of 12.5 to 28 dl / g and an anionization degree of 0.05 meq / g or less. For example, Is slowly heated at a low temperature to polymerize the acrylamide polymer satisfying the above conditions. When the initiation temperature is too high, the intrinsic viscosity is lowered, and the hydrolyzate of acrylamide is formed at the time of the reaction, and the degree of anionization increases, so that the starting temperature is preferably low. More specifically, the starting temperature is preferably 10 ° C to 30 ° C, more preferably 15 ° C to 25 ° C, and even more preferably 18 ° C to 22 ° C. Further, the upper limit of the rising temperature after initiation of polymerization is preferably 80 占 폚 or lower, more preferably 70 占 폚 or lower, and still more preferably 65 占 폚 or lower, since heat generation during polymerization can be easily controlled.

&Lt; Process for producing papermaking additive &gt;

By adding the acrylamide polymer contained in the intermediate of the papermaking additive to the Hoffman decomposition reaction, it is possible to produce a papermaking additive having a sufficient balance of the yield improving effect and the freeness improvement effect.

In the case of carrying out the Hoffman decomposition reaction, the solution obtained by polymerizing the acrylamide polymer may be used as it is, or it may be diluted. If necessary, a separate solution may be prepared.

When the concentration of the acrylamide polymer provided in the Hoffman decomposition reaction is set to a high level, the reaction becomes non-uniform, and a sufficient yield improving effect, a freeness improvement effect and an intelligent power improving effect can not be obtained. In order to sufficiently obtain these effects, the concentration of the acrylamide-based polymer is preferably 2% by mass or less. More preferably 1.5% by mass or less, and further preferably 1% by mass or less. If the concentration of the acrylamide polymer is too low, the efficiency of the Höpmann cracking reaction deteriorates. Therefore, it is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more.

The Hoffman decomposition reaction is carried out under an alkaline condition by reacting the amide group of the acrylamide-based polymer with a halogen acid. The specific pH is in the range of 11-14. For example, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide and the like are used in order to obtain an alkaline condition. Further, in order to activate the hypohalogenous acid, for example, a hypohalogenate such as hypochlorite, hypobromite and hypochlorite is used.

Examples of hypochlorite, hypobromite and hypoiodate include alkali metal salts and alkaline earth metal salts thereof. Examples of the alkali metal of hypochlorous acid include sodium hypochlorite, potassium hypochlorite, lithium hypochlorite and the like.

There is no particular limitation on the amount of the hypohalite salt to be provided in the Hoffman decomposition reaction. However, if the amount of the acrylamide-based polymer relative to the hypohalous acid salt is too small or too large, the amount of the acrylamide polymer or the hypohalogenate salt not used in the reaction increases, The efficiency is lowered. In order to perform the reaction efficiently, the molar ratio of the hypochlorite to the acrylamide polymer is preferably 1:10 to 10:10, more preferably 2.5:10 to 10:10, and even more preferably 5:10 ~ 10: 10.

The temperature in the Hoffman decomposition reaction can be reacted at 0 ° C to 110 ° C. Regarding the combination of the reaction temperature and the reaction time, if the temperature is low or the time is too short, the reaction becomes insufficient, and if the temperature is too high or the time is too long, an undesirable side reaction may occur. Therefore, in order to prevent such a situation and efficiently perform the reaction, for example, by combining the reaction temperature and the reaction time at 10 to 40 DEG C for 30 to 60 minutes or at 50 to 80 DEG C for 10 to 10 minutes Hoffmann decomposition reaction can be carried out.

The reaction can be stopped by adding a reducing agent such as strong acid such as hydrochloric acid, sulfuric acid, acetic acid, sodium sulfite, sodium thiosulfate, ethyl malonate, triethylamine or thioglycerol. In addition, the reaction may be stopped by diluting with a large amount of water or cooling it to a low temperature.

The paper produced by adding the papermaking additive thus obtained has excellent properties in balance of freeness, yield, and intellect.

In the papermaking process, the papermaking additive of the present invention and the conventional papermaking additive may be used in combination.

&Lt; Yeosu-do, Evaluation method of yield improvement effect &gt;

To evaluate the yield improvement effect of Yeosu, 450 ml of CSF (Canadian Standard Freeness) is used as a slurry by first using a 1% pulp slurry of corrugated cardboard of 100% of late paper. Then, the addition rate of the drug (to corrugated cardboard SS) is 500 ppm, and the mixture is stirred at 800 rpm for 10 seconds. Thereafter, Yeosu also evaluates sheet moisture (press dehydrating property) and yield. Yeosu is evaluated by CSF measurement method. The sheet moisture (press dewaterability) is measured by DDA (Dynamic Drainage Analyzer: AB Akribi Kemikonsulter). The yield is measured by DFS (dynamic filtration system: Mutech Co., Ltd.).

&Lt; Evaluation method of the improvement effect of the intelligence &

In order to evaluate the improvement effect of the earthquake, firstly, a handmade paper is manufactured with an Oken type circular water-based paper making machine using slurry of LBKP (hardwood bleached kraft pulp) slurry according to JISP8209 by using various papermaking additives. At this time, the water base paper is made to have a basis weight of 120 g / m ² . The basis weight is measured by the method specified in JIS P 8124. The evaluation of the improvement of the earthquake resistance is performed by measuring the nonparamagnetic strength and the short span of the prepared water base paper. Nonparametric strength refers to the numerical value obtained by dividing the burst strength of the paper in kilopascals (kPa) divided by the basis weight. Short span (uncompressed strength) means a value obtained by shortening the span of a specimen to which a load is applied (0.7 mm) and dividing the maximum load under compression and breaking by the basis weight. The non-breaking strength is measured in accordance with JIS P 8112. In addition, the short span of the produced water-based paper is measured in accordance with JIS P 8156.

Example

EXAMPLES (Polymer A)

198 g of acrylamide (AAM) powder and 793 g of ion-exchanged water were added to a four-necked flask equipped with a stirrer and a temperature sensor, and the monomer weight was adjusted to 20% of the total weight and 990 g of the total weight. Then, the temperature was adjusted to 20 캜, and nitrogen substitution was carried out. An aqueous solution containing 0.2 g of azobis-2-amidinopropane hydrochloride and 0.3 ml of an aqueous solution of 0.1% ammonium persulfate was added to the adjusted solution, and the polymerization was continued for about 5 minutes. . The temperature was gradually increased to about 65 ° C, and the polymerization was completed within 5 hours.

Since the viscosity of the contents increased during polymerization and stirring became difficult, stirring was stopped in the middle. After the polymerization was completed, the contents were taken out. The intrinsic viscosity of this polymer was about 14.8 dl / g. In addition, a very high purity nonionic polymer was obtained with an anionization degree of 0.01 meq / g. In addition, the intrinsic viscosity was measured using a Cannon fescue viscometer and the Huggins equation and the Mead-Fuoss equation were used to calculate the drop time from the measured values. The degree of anionization was measured by the method described in paragraph [0029] of Japanese Patent Application Laid-Open No. 2009-228162.

&Lt; Comparative Example 1 &gt; (Polymer B)

In a four-necked flask equipped with a stirrer and a temperature sensor, 71 g of acrylamide was added, and water was added to make a total amount of 443.8 g. 0.22 g of ammonium persulfate and 0.1 g of sodium hydrogen sulfite were charged to initiate polymerization. The reaction was terminated after 2 hours by keeping at 85 ° C. As a result, a polymer having a polymer concentration of 15% and an intrinsic viscosity of 7.9 dl / g was obtained. During the reaction, hydrolyzate of acrylamide was produced and anionization degree was 0.11 meq / g. (Refer to the polymerization method of Comparative Example 1 described in Patent Document 1)

&Lt; Comparative Example 2 &gt; (Polymer C)

In a four-necked flask equipped with a stirrer and a temperature sensor, 70.93 g of acrylamide and 0.154 g of methylene bisacrylamide were added, and 0.22 g of ammonium persulfate and 0.1 g of sodium hydrogen sulfite were added to initiate polymerization. The reaction was terminated after 2 hours by keeping at 85 ° C. As a result, a polymer having a polymer concentration of 15% and an intrinsic viscosity of 5.5 dl / g was obtained. During the reaction, hydrolyzate of acrylamide was produced and the anionization degree was 0.12 meq / g. (See the polymerization method of Example 1 described in Patent Document 1)

<Hoffman decomposition reaction>

The acrylamide-based polymer obtained in Examples and Comparative Examples 1 and 2 was first diluted to 1% by mass or less. Then, heating was performed, and sodium hypochlorite and caustic soda were added to carry out the reaction. The reaction was quenched with hydrochloric acid. The reaction conditions are shown in Table 1.

Reaction temperature · Starting polymer The molar ratio of sodium hypochlorite to added polymer Reaction time Ionization degree
(meq / g) Example 1 20 캜 Polymer A 5:10 30 minutes 2 Example 2 20 캜 Polymer A 2.5: 10 30 minutes 1.1 Example 3 60 占 폚 Polymer A 5:10 1 minute 1.9 Example 4 70 ° C Polymer A 5:10 30 seconds 1.8 Comparative Example 1 20 캜 Polymer B 5:10 30 minutes 2 Comparative Example 2 20 캜 Polymer C 5:10 30 minutes 1.8

&Lt; Yeosu-do, Evaluation of yield improvement effect &gt;

As a slurry, a 1% pulp slurry of corrugated cardboard paper of 100% of old paper was used to make 450 ml of CSF (Canadian Standard Freeness). (To corrugated cardboard SS) was added so as to be 500 ppm, and the mixture was stirred at 800 rpm for 10 seconds. Thereafter, a measurement test was carried out. The evaluation was carried out by the CSF measurement method. The sheet moisture was measured by DDA. Yield was measured by DFS. The results are shown in Table 2.

Reaction temperature · Starting polymer
Or drug name CSF Yeosu
(Ml) Sheet moisture (%) DDA pressure
(mBar) yield
(%) Example 1 20 캜 Polymer A 216 75.4 243 76.8 Example 2 20 캜 Polymer A 217 75.0 245 76.0 Example 3 60 占 폚 Polymer A 217 75.2 246 76.5 Example 4 70 ° C Polymer A 215 75.1 240 76.2 Comparative Example 1 20 캜 Polymer B 185 76.0 265 69.8 Comparative Example 2 20 캜 Polymer C 173 76.1 273 68.0 Comparative Example 3 Polyethyleneimine 212 75.7 266 73.0 Comparative Example 4 Polyvinylamine 210 75.2 250 77.0 Comparative Example 5 C-PAM 253 78.1 217 80.1 Comparative Example 6 Blank 150 76.7 281 62.5

&Lt; Evaluation of improvement effect of intelligence &

In order to evaluate the effect of improving the intellect, the water base paper was produced by using an Oken type annular water-based paper making machine using various papermaking additives in the LBKP slurry in accordance with JISP8209. At this time, the water base paper was produced so as to have a basis weight of 120 g / m ² . The basis weight was measured by the method specified in JIS P 8124. The non-peat strength of water-base paper was measured in accordance with JIS P 8112. In addition, the short span of the water base paper was measured in accordance with JIS P 8156. The results are shown in Table 3.

Reaction temperature, drug name Non-breaking strength Short span (kN / m) Example 1 20 캜 Polymer A 2.05 3.32 Example 2 20 캜 Polymer A 2.10 3.36 Example 3 60 占 폚 Polymer A 2.08 3.31 Example 4 70 ° C Polymer A 2.06 3.30 Comparative Example 1 20 캜 Polymer B 2.12 3.35 Comparative Example 2 20 캜 Polymer C 2.11 3.19 Comparative Example 3 Polyethyleneimine 1.77 3.07 Comparative Example 4 Polyvinylamine 1.85 3.09 Comparative Example 5 C-PAM 1.60 2.90 Comparative Example 6 Blank 1.67 2.96

Based on the above results, it was confirmed that the polymers of Examples 1 to 4 can be subjected to the Hoffmann reaction under all temperatures of room temperature, 60 ° C, and 70 ° C, and a constant modifying rate can be realized. Further, it was confirmed that these polymers were excellent in freeness degree, press dehydration property (sheet water content), yield and intellect. The polymers of Comparative Examples 1 and 2 were found to have insufficient freeness, dewaterability of press (sheet water content), and yield because the molecular strength was low or the diffusion of molecules was decreased due to crosslinking. In the case of the conventional C-PAM of Comparative Example 5, although the freeness and the yield were excellent, the press dehydration property of the wet paper tended to be lowered, and also the intellect was lowered. Polyethyleneimine and polyethyleneamine have good water dehydration and press dehydration but low intellect. In particular, the yield of polyethyleneimine was low. C-PAM has excellent yield in Yeosu but has low press dehydration and intellect. Therefore, it was found that only the examples 1 to 4 are excellent in all properties in a balanced manner. Further, in Examples 1 to 4, it was confirmed that the sheet resistance (air permeability) was good because the DDA pressure was lower than that of Comparative Examples 1 to 4 and 6. Also, since it was not as low as about 217 which is the value of Comparative Example 5, It was confirmed that the uniformity was maintained.

Claims (4)

An intermediate of a papermaking additive comprising an acrylamide polymer having an intrinsic viscosity of 12.5 to 28 dl / g and an anionic degree of 0.05 meq / g or less. The method according to claim 1,
The intermediate of the papermaking additive in which the crosslinking agent is not added in the polymerization reaction step of producing the acrylamide-based polymer. A process for preparing a papermaking additive comprising the step of adding an intermediate of the papermaking additive according to claim 1 or 2 to a Hoffman decomposition reaction. The method of claim 3,
Wherein in the Hoffman decomposition reaction, the acrylamide-based polymer is provided in the reaction as a solution of 2 mass% or less.