WO2019239819A1

WO2019239819A1 - Paper and paperboard production method

Info

Publication number: WO2019239819A1
Application number: PCT/JP2019/020048
Authority: WO
Inventors: 知世福田; 嘉義陳
Original assignee: 栗田工業株式会社
Priority date: 2018-06-15
Filing date: 2019-05-21
Publication date: 2019-12-19

Abstract

A paper and paperboard production method: which comprises a papermaking step, which uses a paper stock with a cationic demand of at least 100 μeq/L for the papermaking feedstock; and in which a 200-1000 μeq/g cation charge density, 2.7-18.3 dL/g intrinsic viscosity η cationic polyacrylamide is added to the paper stock in a range of 0.005-0.1 mass% with respect to the total solids of the paper stock.

Description

Manufacturing method of paper and paper board

The present invention relates to a method for manufacturing paper and paper board.

Currently, papermaking is performed by a papermaking process in which a raw material slurry in which a pulp raw material is dispersed in water is made. In the paper making process, a large amount of white water containing fine fibers and filler is discharged from a paper machine or the like. The discharged white water is circulated and used in the paper making process from the viewpoint of effective utilization and reuse of water resources.
Various anionic substances such as resins, sizing agents, fluorescent dyes, and latex are contained in papermaking raw materials. In particular, by improving the blending ratio of deinked pulp, mechanical pulp and waste paper contained in papermaking raw materials and reusing white water, anion trash tends to accumulate in the paper manufacturing process, yield decreases, and paper raw materials When a paper layer is formed on the wire with fibers, fillers, and other additives, there is a problem that the wire passes through the wire and flows into white water.

For example, in Patent Document 1, after adding a specific water-soluble polymer (A) to a papermaking raw material before dilution with white water, the papermaking raw material is diluted with white water, and then the specific water-soluble polymer (B). And a method for suppressing the occurrence of defects in paper by an obstructive agent such as anion trash, micropitch, and turbidity component, which is characterized in that paper is made by adding a yield improver as appropriate. In this method, by adding a specific water-soluble polymer in the papermaking raw material, the charge of the anion trash is neutralized, and the micropitch and the turbidity component are fixed to the pulp fiber. It prevents turbidity components from agglomerating.

JP 2009-249756 A

As a water quality index, when the required cation amount is 100 μeq / L or more (for example, a measurement value of a PCD measuring instrument manufactured by Mutech), anion trash increases. When a large amount of various cationic polymers such as coagulants, retention agents, and paper strength agents are added to neutralize the charge of a large amount of anionic trash, a large amount of anionic trash aggregated into strong cations is agglomerated to make paper There is often a problem that the process becomes easy to adhere to tools and equipment, and the situation deteriorates. In the method described in Patent Document 1, sufficient effects cannot be obtained when the amount of anionic trash increases.

The present invention has been made in view of such circumstances, and even when a large amount of anionic trash is contained in white water in the paper making process, the amount of drainage is increased, the yield is improved, and the turbidity is reduced. An object of the present invention is to provide a method for producing paper and paper board.

In order to solve the above problems, the present inventors have intensively studied and found that the problems can be solved by adding a specific amount of a specific low cationic polyacrylamide to the total solid content of the paper.
The present invention has been completed based on such findings.

That is, the present disclosure relates to the following.
[1] A cation having a papermaking process using a paper stock having a cation requirement of 100 μeq / L or more as a papermaking raw material, a cation charge density of 200 to 1000 μeq / g, and an intrinsic viscosity η of 2.7 to 18.3 dL / g A method for producing paper and paper board, in which a functional polyacrylamide is added to a paper stock in a range of 0.005 to 0.1% by mass relative to the total solid content of the stock.
[2] The method for producing paper and paper board as described in [1] above, wherein the paper stock is a papermaking raw material containing mechanical pulp.
[3] The paper and paper board manufacturing method according to the above [1], wherein the paper stock is a papermaking raw material containing 30% by mass or more of deinked pulp.
[4] The paper and paper board manufacturing method according to the above [1], wherein the paper stock is a papermaking raw material containing 30% by mass or more of waste paper pulp.

ADVANTAGE OF THE INVENTION According to this invention, even when it contains many anionic trash in white water in a papermaking process, the amount of drainage is increased, the yield rate is improved, and the manufacturing method of paper and a paper board which can reduce turbidity is provided. be able to.

It is a block diagram which shows the manufacturing method of the paper and paper board which concern on one Embodiment of this invention.

A method for producing paper and paper board according to an embodiment of the present invention (hereinafter sometimes referred to as “this embodiment”) includes a papermaking process using a paper material having a cation requirement of 100 μeq / L or more as a papermaking raw material. A cationic polyacrylamide having a cationic charge density of 200 to 1000 μeq / g and an intrinsic viscosity η of 2.7 to 18.3 dL / g of 0.005 to 0.1% by mass based on the total solid content of the paper It is characterized by being added to the stock in a range.
When a paper material having a cation requirement of 100 μeq / L or more is used as a papermaking raw material, a large amount of anionic trash is contained in white water in the papermaking process. In contrast, in this embodiment, a specific amount of cationic polyacrylamide having a cationic charge density of 200 to 1000 μeq / g and an intrinsic viscosity η of 2.7 to 18.3 dL / g is added to the total solid content of the paper. Thus, agglomeration of anion trash can be suppressed, thereby increasing the amount of drainage, improving the yield, and reducing turbidity.

The cationic polyacrylamide used in the method for producing paper and paper board according to this embodiment has a cationic charge density of 200 to 1000 μeq / g. Here, the cation charge density refers to the equivalent number (μeq / g) of the cation charge in the monomer unit constituting the polymer.
If the cation charge density is less than 200 μeq / g, the amount of drainage may decrease, and if it exceeds 1000 μeq / g, the effect of reducing turbidity may not be obtained. From such a viewpoint, the cationic charge density is preferably 200 to 700 μeq / g, more preferably 200 to 300 μeq / g.
The cationic charge density can be determined by the method described in the examples.

The cationic polyacrylamide has an intrinsic viscosity η of 2.7 to 18.3 dL / g. If the intrinsic viscosity η is less than 2.7 dL / g, the molecular weight of the cationic polyacrylamide is too small, so that the range in which the agglutination reaction can occur is narrow, and a sufficient yield effect may not be obtained. On the other hand, when the intrinsic viscosity η exceeds 18.3 dL / g, the molecular weight of the cationic polyacrylamide is too large, so that the viscosity is high and the effect of increasing the drainage amount may not be sufficiently exhibited. From such a viewpoint, the intrinsic viscosity η is preferably 9 to 18 dL / g, more preferably 13 to 18 dL / g.
The intrinsic viscosity η is calculated by measuring the flow time at 30 ° C. using a Cannon-Fenske viscometer and using the Huggins equation and the Mead-Fuoss equation from the measured value.

The cationic polyacrylamide is not particularly limited as long as the cationic charge density and the intrinsic viscosity η are within the above ranges, for example, an aqueous polymerization method, an emulsion polymerization method, a suspension polymerization method using an acrylamide monomer and a cationic monomer. It can obtain by well-known polymerization methods, such as. The charge density is adjusted by the mixing ratio of the monomer used, and the intrinsic viscosity is adjusted by the polymerization temperature, the monomer concentration, and the amount of initiator added.
Examples of the cationic monomer include (meth) acrylic acid ester derivatives such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; and (meth) acrylic acid derivatives such as dimethylaminopropyl (meth) acrylamide and diethylaminopropyl (meth) acrylamide. ) Acrylamide derivatives; quaternary salts and acid salts of dimethylaminoethyl (meth) acrylate; tertiary amino monomers and tertiary amine monomers such as allylamine and diallylamine, and quaternary salts and acid salts thereof. Of these, quaternary salts of dimethylaminoethyl (meth) acrylate are preferably used.
These cationic monomers can be used alone or in combination of two or more.

The blending ratio of the cationic monomer with respect to the total amount of the monomer derived from all structural units of the cationic polyacrylamide is preferably 0.5 to 9.5 mol%, more preferably 1 to 8 mol%. By setting the proportion of the cationic monomer within the above range, the cationic charge density of the cationic polyacrylamide can be within the above range.
Further, the blending ratio of the acrylamide monomer with respect to the total amount of the monomer derived from all the structural units of the cationic polyacrylamide is preferably 90.5 to 99.5 mol%, more preferably 92 to 99 mol%.

The polymerization initiator used in producing the cationic polyacrylamide is not particularly limited, and examples thereof include ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, and tert-butyl peroxide. Etc. A polymerization initiator can use 1 type (s) or 2 or more types.

Also, it is preferable to use a chain transfer agent in order to adjust the viscosity of the cationic polyacrylamide to be synthesized. The chain transfer agent is not particularly limited, and examples thereof include chlorine tetrachloride, chloroform, carbon tetrachloride and the like. One or more chain transfer agents can be used.

FIG. 1 is a block diagram illustrating a paper and paper board manufacturing method according to an embodiment of the present invention.
The papermaking system 10 includes a raw material system 20, a preparation, papermaking system 30, and a recovery system 40.
The raw material system 20 produces pulp from paper raw materials. The raw material system 20 in this embodiment includes a raw material tank (1) 21 and a raw material tank (2) 22. The raw material tank (1) 21 includes chemical pulp such as hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), and softwood unbleached kraft pulp (NUKP); ground pulp ( GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP), and other mechanical pulp are accommodated, and raw material tank (2) 22 contains corrugated wastepaper pulp and liner wastepaper pulp. Waste paper pulp such as magazine waste paper pulp, newspaper waste paper pulp, Jiju waste paper pulp, Kamihaku waste paper pulp, and deinked waste paper pulp is accommodated.

The pulp accommodated in the raw material tank (1) 21 and the raw material tank (2) 22 is supplied to the mixing chest 23 at an appropriate ratio and mixed in the mixing chest 23. The mixed pulp is transferred to the seed box 25 after adding papermaking chemicals such as a sticky agent in the machine chest 24.
The raw material tank (1) 21, the raw material tank (2) 22, the mixing chest 23, the machine chest 24, and the seed box 25 constitute the raw material system 20 of the present embodiment.

Preparation, papermaking system 30 prepares pulp and makes paper. The pulp stored in the seed box 25 is supplied to the white water silo 31, and then sequentially supplied to the cleaner 33 by the pump 32. Further, the liquid is supplied to the screen 36 by the pump 35, and after the foreign matter is removed here, the liquid is supplied to the inlet 37. The inlet 37 suppresses flocs and flow stripes by supplying pulp to the wire of the wire part 38 at an appropriate concentration, speed, and angle. The supplied pulp is dehydrated with a wire part 38 and a press part (not shown), and then dried with a dryer part (not shown), and then subjected to appropriate processing to produce paper.

Here, the liquid separated by the wire part 38 is white water 39. The white water 39 contains fine fibers derived from raw material pulp normally used for paper making, other papermaking chemicals, and the like.
The white water 39 separated by the wire part 38 is stored in the white water silo 31. Part of the white water stored in the white water silo 31 is supplied to the pump 32, and the rest is supplied to the white water recovery device 41.
The white water silo 31 to the wire part 38 constitute the preparation and paper making system 30 of this embodiment.

The collection system 40 prepares and collects white water from the papermaking system 30. The supplied white water is transferred to the white water recovery device 41, filtered by the white water recovery device 41, and solid-liquid separated. The solid content is transferred to the machine chest 24, and the filtrate is recovered into the recovered water tank 42 and stored. A part of the filtrate is further filtered and used as adjustment water for adjusting the concentration of white water discharged to the outside or circulating.
The white water recovery device 41 and the recovery water tank 42 constitute the recovery system 40 of the present embodiment.

White water and adjustment water may contain a small amount of papermaking chemicals as long as the effects of the present invention are not impaired.
The papermaking agent is not particularly limited, and examples thereof include surfactants, waxes, sizing agents, fillers, rust inhibitors, conductive agents, antifoaming agents, slime control agents, dispersants, viscosity modifiers, flocculants, and coagulation agents. Agents, paper strength enhancers, yield improvers, paper powder fall-off preventing agents, bulking agents and the like.

The addition of the above-mentioned cationic polyacrylamide to the stock (pulp) can be achieved by supplying pulp from the mixing chest 23 to the machine chest 24 or from the machine chest 24 (I), the machine chest 24 to the seed box 25. Or seed box 25 (II), supply line from seed box 25 to white water silo 31 or white water silo 31 (III), supply line from white water silo 31 to pump 32 or pump 32 (IV), pump 32 to cleaner 33 Supply line or cleaner 33 (V), supply line from cleaner 33 to pump 35 or pump 35 (VI), supply line from pump 35 to screen 36 or screen 36 (VII), supply from screen 36 to inlet 37 Line or inlet 37 (VIII), wire part 38 Can be carried out in the transfer line to the white water silo 31 of the separated white water (IX), the transfer line or the white water recovery device 41 from the white water silo 31 whitewater to white water recovery device 41 (X). Among these, from the viewpoint of suppressing agglomeration of anionic trash, the addition of cationic polyacrylamide is preferably any of the above (IV), (V), (VI), (VII), and (VIII), Any of (VI), (VII), and (VIII) is more preferred.

In the method for producing paper and paper board of this embodiment, agglomeration of anionic trash can be suppressed by adding cationic polyacrylamide. Can be used, and a papermaking raw material containing 30% by mass or more of waste paper pulp can be used.

The amount of the cationic polyacrylamide added is 0.005 to 0.1% by mass with respect to the total solid content of the paper. If it is less than 0.005% by mass, the coagulation effect is low, and the yield / drainage effect cannot be fully exhibited. On the other hand, if it exceeds 0.1% by mass, the coagulation effect is too strong, which may affect the quality of the product. From such a viewpoint, the addition amount of the cationic polyacrylamide is preferably 0.01 to 0.08% by mass, more preferably 0.02 to 0.06% by mass with respect to the total solid content of the paper.

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

[Cation charge density]
Deionized water was added and dissolved using a graduated cylinder so that the sample concentration was 0.005% (w / v). Adjust the pH to 4 using hydrochloric acid (HCl) or sodium hydroxide (NaOH) solution, and drop the polyvinyl potassium sulfate solution until the color of the toluidiline blue indicator changes. The charge density was determined.

[Intrinsic viscosity η]
Using a Canon Fenceke viscometer (No. 75 manufactured by Kusano Scientific Instruments Co., Ltd.), the flow time was measured at 30 ° C., and calculated from the measured value using the Huggins formula and the Mead-Fuoss formula. did.

The cationic acrylamide can be synthesized by a known polymerization method, for example, an aqueous polymerization method, an emulsion polymerization method, or a suspension polymerization method. The polymerization examples shown below are only examples thereof and do not limit the production method.
(Synthesis Example 1: Synthesis of cationic polyacrylamide A)
In a 1 L separator-type flask with cooling jacket, 720 g of water, 71.5 g of acrylamide (AAm) (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), quaternary salt of dimethylaminoethyl acrylate (DAA) (Fuji Film Wako Pure Chemical ( 8.5 g) and 0.008 g of carbon tetrachloride (Fuji Film Wako Pure Chemical Industries, Ltd.) as a chain transfer agent were added. When the temperature reached 50 ° C., the initiator (Fuji Film Wako Pure Chemical ( 0.005 g) was added and stirred. Next, when the temperature reached 60 ° C., stirring was stopped and the temperature was kept for 4 hours. Then, it cooled and the cationic polyacrylamide A was obtained.
The cationic charge density and intrinsic viscosity η of the obtained cationic polyacrylamide A were measured by the above-described methods. The results are shown in Table 1.

(Synthesis Examples 2 to 8: Production of cationic polyacrylamides B to H)
Cationic polyacrylamides B to H of Synthesis Examples 2 to 8 were synthesized in the same manner as Synthesis Example 1 except that the monomer ratios shown in Table 1 were changed. The obtained cationic polyacrylamides B to H were measured for the cationic charge density and intrinsic viscosity η by the methods described above. The results are shown in Table 1.

The following measurements were performed on the sample solutions obtained in the examples and comparative examples. The results are shown in Table 2-1, Table 2-2 and Table 3.

[Required amount of cation]
The pulp slurry was filtered through a 150 μm pass filter cloth, and the filtrate was collected. The filtrate was put into a flow potential meter (PCD (Particle Change Detector) -03 type, manufactured by Mutech), and the required amount of cation was measured from the amount of titrant (Poly-DADMAC, manufactured by Kishida Chemical Co., Ltd.). .

[Drainage amount]
Using a drainage tester with an 80 mesh wire and a pipe through which water is removed at the bottom of a cylindrical tester, water in the pulp sample collected in the cylinder by opening and closing the valve falls down through the mesh wire. The amount of drainage for 10 seconds at this time was measured with a graduated cylinder.
In addition, productivity is improved, so that there is much drainage amount compared with the blank which does not add cationic polyacrylamide.

[Yield rate]
The filtrate was collected using a filtrate yield tester (DFS-03, manufactured by Mutech), the suspended solid content concentration (SS concentration) was measured, and the yield rate was calculated by the following formula.
In addition, compared with the blank which does not add cationic polyacrylamide, a white water density | concentration can be reduced and the load of wastewater treatment can be reduced, so that a yield rate is high. In addition, the cost can be reduced by saving raw materials.
Yield rate (%) = (1−SS concentration of filtrate / SS concentration of stock) × 100

[Ash yield rate]
The filtrate suspension collected by the filtrate yield tester was baked at 600 ° C. for 6 hours in an electric furnace, the remaining ash was measured, and the ash yield was calculated from the following formula.
In addition, since the yield effect of fillers, such as a calcium carbonate, is anticipated, so that the ash yield rate is high compared with the blank which does not add cationic polyacrylamide, the cost reduction by saving of a filler can be aimed at.
Ash content yield (%) = (1−ash content of filtrate / ash content of paper) × 100

[Turbidity]
It was measured using a portable turbidimeter (2100Q, manufactured by Toa DKK Corporation).
In addition, compared with the blank which does not add cationic polyacrylamide, as the turbidity is lower, dirt in the system is reduced, and the risk of defects and paper breakage can be reduced.

[Test 1] Confirmation test at the laboratory level (Example 1)
The paper stock collected from the production center core paper was used for the experiment (cation requirement (CD) 395 μeq / L). Take 180 mL of the stock in a container, add 0.005% by mass of a solution obtained by dissolving the cationic polyacrylamide B obtained in Synthesis Example 2 in 0.1% by mass, and stir at 800 rpm for 20 seconds. Prepared.

(Examples 2 to 15 and Comparative Examples 1 to 16)
A sample solution was prepared in the same manner as in Example 1 except that the cationic polyacrylamide B was changed to the cationic polyacrylamide shown in Table 2-1 and added in the amount shown in Table 2-1.

(Examples 16 to 27, Comparative Examples 17 to 25)
The cationic polyacrylamide B was changed to the cationic polyacrylamide shown in Table 2-2 and added in the amount shown in Table 2-2. Further, Zetaace S701 (Kurita Industry ( Co., Ltd.) and PAC (polyaluminum chloride) were added in the same manner as in Example 1 except that they were added in the amounts shown in Table 2-2.

(Example 28)
The paper stock was adjusted by adding 15 wt% calcium carbonate (manufactured by Shiroishi Kogyo Co., Ltd.) as a filler to LBKP (CD = 230 μeq / L) containing 25 wt% coat waste paper. 180 mL of the paper stock was placed in a container, and 0.01% by mass of the cationic polyacrylamide E obtained in Synthesis Example 5 was added thereto, followed by stirring at 800 rpm for 20 seconds to prepare a sample solution.

(Example 29, Comparative Examples 26 to 28)
A sample solution was prepared in the same manner as in Example 28 except that the cationic polyacrylamide E was changed to the cationic polyacrylamide shown in Table 2-2 and added in the amount shown in Table 2-2.

A specific amount of cationic polyacrylamide having a cationic charge density of 200 to 1000 μeq / g and an intrinsic viscosity η of 2.7 to 18.3 dL / g was added to a paper having a high cation requirement (100 μeq / L or more). It can be seen that Examples 1 to 29 all have a higher drainage amount, lower turbidity, and improved yield compared to blanks to which no cationic polyacrylamide was added. In addition, in Examples 1 to 29, the amount of drainage was larger than in the comparative example to which cationic polyacrylamide having a cationic charge density of less than 200 μeq / g was added, and the cation charge density exceeded 1000 μeq / g. It can be seen that the turbidity is low and the yield is improved as compared with the comparative example to which the functional polyacrylamide is added.

[Test 2] Test at actual machine level (Example 30)
In the paper and paper board manufacturing process shown in FIG. 1, 180 mL of (VII) paper material (CD = 400 μeq / L) before being supplied from the pump 35 to the screen 36 was collected in a container. To this, 0.01% by mass of the cationic polyacrylamide E obtained in Synthesis Example 5 was added, and stirred at 800 rpm for 20 seconds to prepare a sample solution.

(Example 31, Comparative Examples 29 to 31)
A sample solution was prepared in the same manner as in Example 30 except that the cationic polyacrylamide E was changed to the cationic polyacrylamide shown in Table 3 and added in the amount shown in Table 3.

A specific amount of cationic polyacrylamide having a cationic charge density of 200 to 1000 μeq / g and an intrinsic viscosity η of 2.7 to 18.3 dL / g was added to water quality having a high cation requirement (100 μeq / L or more). In Examples 30 and 31, both the amount of drainage was low, the turbidity was low, and the yield rate was improved compared to Comparative Examples 30 and 31 to which cationic polyacrylamide having a cationic charge density exceeding 1000 μeq / g was added. I understand that. In addition, the yield rate of ash is improved, and a reduction in the amount of filler used can be expected.

The method for producing paper and paper board of the present invention can increase the amount of drainage, improve the yield, and reduce the turbidity even in the case of containing a large amount of anionic trash in the white water in the paper making process.

10: Papermaking system 20: Raw material system 21: Raw material tank (1)
22: Raw material tank (2)
23: mixing chest 24: machine chest 25: seed box 30: preparation, papermaking system 31: white water silo 32, 35: pump 33: cleaner 34: regulator 36: screen 37: inlet 38: wire part 39: white water 40: recovery System 41: White water recovery device 42: Recovery water tank

Claims

Cationic polyacrylamide having a paper making process using a paper material having a cation requirement of 100 μeq / L or more as a papermaking raw material, a cationic charge density of 200 to 1000 μeq / g, and an intrinsic viscosity η of 2.7 to 18.3 dL / g Is added to the paper stock in the range of 0.005 to 0.1% by mass with respect to the total solid content of the paper stock.
The method for producing paper and paper board according to claim 1, wherein the paper stock is a papermaking raw material containing mechanical pulp.
The method for producing paper and paper board according to claim 1, wherein the paper stock is a papermaking raw material containing 30% by mass or more of deinked pulp.
The method for producing paper and paper board according to claim 1, wherein the paper stock is a papermaking raw material containing 30% by mass or more of waste paper pulp.