JPH0959891A - Papermaking of paperboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase papermaking speed by adding a polymeric coagulant to paper stock predominant in waste paper pulp to raise the flocculating tendency of the paper stock followed by blending the system with a polymeric flocculant to improve the freeness and dryability of the paper stock. SOLUTION: First, 2-20ppm of a polymeric coagulant having quaternary ammonium salt-type cationic group such as a polydimethyl allylammonium salt or dimethylamine's epichlorohydrin condensate derivative is added to a paper stock containing >=70wt.% of waste paper-disaggregated pulp to remove the adverse effect of flocculation inhibitory matter in the waste paper pulp and raise the flocculating tendency of the paper stock. Subsequently, the resultant system is incorporated with a high-polymerization-degree polymeric flocculant >=10dl/g in intrinsic viscosity (determined in the form of 2% aqueous ammonium sulfate solution) prepared by copolymerization of 10-60mol% of a quaternarized product of dimethylaminoethyl acrylate such as acryloyloxyethyl trimethylammonium salt and/or acryloyloxydimetylthyl benzylammonium salt with acrylamide, followed by conducting a papermaking process to obtain the objective paperboard.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for making paperboard from waste paper disaggregated pulp as a raw material while making papermaking inhibitor into the papermaking paper. The above object is achieved by adding a polymer flocculant having excellent cohesiveness to a paper material which has been pretreated to improve cohesiveness.

[0002]

2. Description of the Related Art Various drainage improvers have been proposed so far. For example, Hoffmann degradation products of polyethyleneimine and polyacrylamide are famous as drainage improving agents, and also as acrylic drainage improving agents.
It is known that acrylate cations such as 395 and JP 61-6396 are effective. Japanese Patent Laid-Open No. 5-2
No. 63387 discloses a diallyl dimethyammonium chloride polymer having a molecular weight of 500,000 to 1,000,000 and a molecular weight of 200.
A pulp slurry dehydrating agent consisting of 10 to 20 million dimethylamiethylmethacrylate polymers is described.
Further, various amphoteric methacrylates are known as many papermaking agents. Further, as a sludge dehydrating agent, a cationic copolymer comprising an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit (Japanese Patent Laid-Open No. 62-262799) is known. The effect of the drainage improver is to improve the papermaking speed, but it is often used for the purpose of increasing paper strength.
That is, if the degree of beating of the pulp is improved, it is possible to increase the paper strength, but there is a disadvantage that the paper making speed is reduced. By using a drainage improver, it is possible to maintain the filtration rate and the drying rate of wet paper web at a level similar to that of a pulp with a high beating degree even for a pulp with a high beating degree, and substantially It is possible to make high-performance paper by making a paper stock using pulp with a high beating degree without slowing down the production rate, and it is regarded as an important paper-making chemical. Furthermore, there is a movement to reduce costs by using low quality raw materials by using such chemicals.

[0003]

DISCLOSURE OF THE INVENTION There is a disintegrated pulp of waste paper as a low cost pulp raw material, and if this pulp is used as a main raw material to make paper, a significant cost reduction can be achieved. However, since the disaggregated pulp of waste paper contains a large number of aggregation-inhibiting substances such as binders, even if the above-mentioned polymer flocculant is added, a sufficient aggregation effect cannot be exhibited. For this reason, when paperboard made from waste paper disaggregated pulp as the main raw material is made by the conventional flocculation method, a large amount of suspended solids pass through the wire surface, which may cause clogging of the wire and reduce the filtration speed or wear of the wire. Was causing it. The present invention solves the above problems, reduces the wear of the wire, improves the filtration speed, and improves the drying speed by improving the drainage at the time of pressing due to the cohesive action, and improves the papermaking speed together with the effect. I can do things.

[0004]

According to the invention of claim 1, when a paperboard is made using a paper material whose main raw material is waste paper disintegrated pulp, a polymer coagulation having a quaternary ammonium salt type cationic group is used. A papermaking method for paperboard, which comprises adding a polymer flocculant comprising a copolymer containing quaternary dimethylaminoethyl acrylate and acrylamide after adding the agent. The invention according to claim 2 is the method for making paperboard according to claim 1, wherein the blending ratio of the waste paper disaggregation pulp is 70% by weight or more of the total pulp. The invention of claim 3 is the papermaking method for paperboard according to claim 1, wherein the polymer coagulant having a quaternary ammonium salt type cationic group is a polydimethyldiallylammonium salt. The invention according to claim 4 is the method for making paperboard according to claim 1, wherein the polymer coagulant having a quaternary ammonium salt type cationic group is a derivative of an epichlorohydrin condensate of dimethylamine. is there. The coagulant according to claim 3 and claim 4 has a low foaming property, and a filler / binder or fine fibers derived from a raw material such as coated paper is spread as a fine floc on the surface of the long fibers to hold the polymer, and the polymer flocculant is added at a later stage. Promote the effect of. Claim 5
The invention of (1) is the papermaking method for paperboard according to claim 1, wherein the quaternary compound of dimethylaminoethyl acrylate is acryloyloxyethyl trimethyl ammonium salt and / or acryloyl oxyethyl dimethyl benzyl ammonium salt. The invention according to claim 6 is the papermaking method for paperboard according to claim 1, characterized in that the copolymerization ratio of the quaternized product of dimethylaminoethyl acrylate is 10 to 60 mol% based on all the monomers. 10 mol%
When the amount is less than 60%, the water catching property of the wet paper web increases and the drying property deteriorates, and when it is more than 60 mol%, the cohesive force becomes weak. According to a seventh aspect of the present invention, the polymer flocculant comprising a copolymer containing quaternary dimethylaminoethyl acrylate and acrylamide is a polymer flocculant comprising quaternary dimethylaminoethyl acrylate and acrylamide. The papermaking method for paperboard according to claim 1, wherein Claim 8
Of the present invention, a polymer flocculant consisting of a quaternary product of dimethylaminoethyl acrylate and a copolymer containing acrylamide comprises a quaternary product of dimethylaminoethyl acrylate, acrylamide and 5 to 20 mol% of acrylic acid. The papermaking method for paperboard according to claim 1, wherein the method is a molecular flocculant.

According to a ninth aspect of the present invention, a polymer flocculant consisting of a copolymer containing quaternary dimethylaminoethyl acrylate and acrylamide has an intrinsic viscosity of 10 dl / g or more in a 2 wt% ammonium sulfate aqueous solution. The papermaking method for paperboard according to claim 1, wherein When the intrinsic viscosity is low, the cohesiveness is weak, and when the intrinsic viscosity is high, the cohesiveness is strong. In the present invention, the stronger the cohesiveness, the higher the papermaking speed. The reason why the present invention uses a quaternary ammonium salt type cationic polymer as a coagulant and a coagulant is because it has an advantage of having a small foaming property. Amine-based cationic polymers have a drawback that they have a strong foaming property as typified by polyethyleneimine. This phenomenon seems to be due to the strong hydrophilicity of the quaternary ammonium salt, but it is an empirical fact that the addition amount of the amine-based coagulant / coagulant is limited due to the foaming property and sufficient coagulation is achieved. The effect cannot be acknowledged. On the other hand, in the present invention, there is no limitation on the addition amount, and it is not necessary to consider the influence of the foaming property for neutralizing the charge and exerting the crosslinking and adsorbing action.

[0006] The coagulant can remove the adverse effect of the aggregation inhibitor by adding 2 to 20 ppm of the coagulant. The coagulant is appropriately added in an amount of 50 to 500 ppm with respect to the pulp. The acryloyloxyethyl-type cationic polymer has a stronger cohesive force than the methacryloyloxyethyl-type cationic polymer because the arrangement of the cationic groups is random. The present invention is characterized in that a coagulant having a strong cohesive force is added to a stock material pretreated with a coagulant. The higher the degree of polymerization, the stronger the cohesive force, and the intrinsic viscosity, which is an index of the degree of polymerization, is 5 dl / g, preferably 10 dl / g or more, expressed as the intrinsic viscosity in an aqueous solution of ammonium sulfate having a concentration of 2% by weight. . In the present invention, the degree of polymerization or molecular weight of the coagulant has no significant meaning, and a commercially available coagulant grade can be used as it is. The stirring after adding the coagulant is generally performed by adding it to the seed box or the fan pump inlet, but it may be added to the centrifugal strainer inlet.

[0007]

[Function] Used raw paper is newsprint, corrugated paper, coated paper, and others, and used disintegrated pulp has drainage and drying properties due to anionic substances such as lignin and fillers and binders (that is, pastes) derived from coated paper. Getting worse. Since these papermaking inhibitors have the same behavior as the fine fibers, the papermaking inhibitors are also formed into paper by removing the fibers from the stock system by aggregating the fine fibers and making them out together with the long fibers.
When a large amount of papermaking inhibitor is present, it is adsorbed and coated on the surface of the droplet of the high-molecular-weight aggregating agent aqueous solution to prevent the cross-linking and adsorbing action of the long fibers, thereby causing aggregation inhibition. When the coagulant is added, the paper-making inhibiting substance forms fine flocs together with the fine fibers and is removed from the liquid, so that it does not interfere with the aggregation of the long fibers.

[0008]

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) A monomer mixture is adjusted to an aqueous solution with a total monomer concentration of 15% by weight in deionized water, and dissolved oxygen is removed by aeration with nitrogen. After the temperature of the aqueous solution of the monomer after deoxidation was adjusted, 2,2′-azobis-2amidinopropane dihydrochloride was added to carry out polymerization to obtain a polymer. Table 1 shows the monomer composition ratio and the physical properties of the polymer.

[0010]

[Table-1]

(Example-1) Waste paper disintegrated pulp 80%, semi-chemical pulp 20%, inlet concentration 6000 pp
A papermaking test was conducted by using a four-layer papermaking machine with a four-ply gauze cylinder and a papermaking machine having a circulation ratio of 28 times and a PH of 5.8. A 1% aqueous solution of a coagulant was added to the inlet of the fan pump, and a 0.2% aqueous solution of a coagulant was added to the inlet of the screen, and the improvement in papermaking speed was compared. 100 for coagulant / coagulant addition conditions and no chemical injection
The productivity is shown in Table 2.

[0012]

[Table-2]

(Example-2) A filtration table test was conducted using the paper material used in Example-1. Each sample was added to and mixed with the stock material used in Example-1 with a filter having a 40-mesh wire net at the bottom of a cylinder having a diameter of 6 cm.
The amount of drainage in the initial 5 seconds after pouring c is shown in Table 3.

[0014]

[Table-3]

[0015]

EFFECTS OF THE INVENTION Polyethyleneimine and polyalkylenepolyamine are remarkably foamed and cannot be compared. The present invention, by using a low molecular weight quaternary ammonium salt type cationic polymer coagulant together without using acryloyloxyethyl type cationic polymer coagulant having a stronger cohesive force than methacryloyloxyethyl type, Filterability,
A clear increase in the papermaking speed is recognized as the drying property is improved. This is an effect due to the production of the paper-making inhibitor, and various troubles due to the paper-making inhibitor can be avoided, and good papermaking can be obtained.

Claims (9)

[Claims] 1. When making a paperboard using a paper material containing waste paper disintegrated pulp as a main raw material, a quaternary ammonium salt type cationic group-containing polymer coagulant is added and then dimethylaminoethyl acrylate 4 is added. A papermaking method for paperboard, which comprises adding a polymer flocculant comprising a copolymer containing a graded product and acrylamide. 2. The papermaking method for paperboard according to claim 1, wherein the blending ratio of the waste paper disaggregation pulp is 70% by weight or more of the total pulp. 3. The papermaking method for paperboard according to claim 1, wherein the polymer coagulant having a quaternary ammonium salt type cationic group is a polydimethyldiallylammonium salt. 4. The papermaking method for paperboard according to claim 1, wherein the polymeric coagulant having a quaternary ammonium salt type cationic group is a derivative of an epichlorohydrin condensate of dimethylamine. 5. A dimethylaminoethyl acrylate 4
The graded product is an acryloyloxyethyl trimethyl ammonium salt and / or an acryloyl oxyethyl dimethyl benzyl ammonium salt.
The papermaking method for paperboard according to. 6. A dimethylaminoethyl acrylate 4
Copolymerization ratio of graded product is 10 to 60 mol% based on all monomers
The papermaking method for paperboard according to claim 1, wherein 7. Dimethylaminoethyl acrylate 4
The papermaking paper for paperboard according to claim 1, wherein the polymer flocculant composed of a copolymer containing a graded product and acrylamide is a polymer flocculant composed of a quaternized product of dimethylaminoethyl acrylate and acrylamide. Method. 8. A dimethylaminoethyl acrylate 4
The polymer flocculant composed of a copolymer containing a grading product and acrylamide is characterized in that it is a quaternary product of dimethylaminoethyl acrylate, acrylamide and a polymer flocculant composed of 5 to 20 mol% of acrylic acid. The papermaking method for paperboard according to claim 1. 9. Dimethylaminoethyl acrylate 4
The papermaking method for paperboard according to claim 1, wherein the polymer flocculant comprising a copolymer containing a graded product and acrylamide has an intrinsic viscosity of 10 dl / g or more in an aqueous 2% by weight ammonium sulfate solution. .