JPH0978487A - Improving agent for yield of filler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a chemical, capable of efficiently improving the quality of the formed paper by addition thereof to a papermaking process for a sheet of paper containing a filler in a paper factory and optimal for both a method for preventing a raw material from running off and a method for prolonging the life of a wire. SOLUTION: This improving agent for the yield of a filler comprises an acrylic cationic water-soluble polymer containing >=5mol% each of an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit. This improving agent is added to a papermaking process for a sheet of paper containing the filler. The polymer has >=10dl/g intrinsic viscosity measured in an aqueous solution of ammonium sulfate at 2wt.% concentration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel filler retention improver composed of a cationic polymer. The filler retention improver of the present invention improves the quality of paper and prevents the runoff of raw materials, The purpose is to extend the service life.

[0002]

2. Description of the Related Art Various filler retention improvers have been proposed so far. For example, as a Hoffmann degradation product of polyacrylamide, a Mannich modified product of polyacrylamide, and an acrylic filler yield improver, JP-A-61-639.
It is known that acrylate cations such as JP-A No. 7 and JP-A No. 61-6398 are effective. 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.

As described above, the effect of the filler retention improver is to produce high quality paper by reducing the difference between the front and back sides of the paper or to average the composition distribution in the thickness direction of the paper layer, and the loss of raw materials. It is possible to reduce the cost by preventing the above, and it is also possible to reduce the density of the stock material. Therefore, there is an advantage that it is easy to mass-produce a certain quality of paper by controlling the variation of the paper. In addition, it is general to use a plastic wire instead of bronze for the recent machine wire, and there is a drawback that the abrasion due to the wire passing filler is remarkable as a characteristic of the plastic wire. It is obvious that the filler retention improver can reduce the filler passing through the wire, and naturally has the effect of extending the life of the wire. Although such an effect was recognized even with the conventional chemicals, the conventional chemicals were insufficient for the above-mentioned purpose, and a new chemical was required.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to produce high quality paper by averaging the composition distribution in the thickness direction of the paper layer by using the filler retention improver. It is possible to prevent the loss of raw materials, to reduce the cost, and to reduce the density of the stock material, so that it is easy to mass-produce the paper of a certain quality by controlling the variation of the papermaking. An advantage is to provide a papermaking chemical that can extend the life of a plastic wire.

[0005]

The invention according to claim 1 is an acrylic cationic water-soluble aqueous solution containing 5 mol% or more of an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit, respectively. It is a filler retention aid composed of a water-soluble polymer. The filler retention improver according to claim 1, wherein the invention of claim 2 is a copolymer comprising an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit. is there. The invention of claim 3 is the filler retention improver according to claim 1, wherein the total amount of the cationic monomer structural units is 15 mol% or more. When the amount of the cationic groups is small, the yield effect of the filler is low, the loss of the raw material is large, and the difference between the front and the back of the paper is large, so that high quality paper cannot be made. A fourth aspect of the present invention is the filler retention improver, which has an intrinsic viscosity of 10 dl / g or more in an aqueous solution of ammonium sulfate having a concentration of 2% by weight. The intrinsic viscosity is an index of the molecular weight, but when the molecular weight is low, the cohesive force is weak, the yield effect of the filler is low, and the difference between the front and back tends to be large. In the invention of claim 5, the acrylic cationic water-soluble polymer contains a dispersant comprising a polyelectrolyte.
A polymer dispersion in a polyvalent anion salt aqueous solution, wherein the dispersion has (1) a cationic water-soluble polymer concentration of 5% by weight or more in the dispersion, and (2) a cationic water-soluble polymer in the dispersion. The average particle size of the coalescence is 0.1 to 150 microns (3) The viscosity of the dispersion is 10 to 3000 CP at room temperature
(4) The salt concentration in the dispersion is 15% by weight or more and the saturation concentration or less (5) The dispersant concentration in the dispersion is 1 to 15% by weight with respect to the cationic water-soluble polymer. It is a filler yield improver characterized by easy workability.

A cationic polyelectrolyte in which a benzyldimethylammonium salt type cationic group and a trimethylammonium salt type cationic group coexist in the same polymer together with an acrylamide structural unit is generally used because of its unique synergistic effect. Has stronger cohesive force than other cationic polymer flocculants. Moreover, this functional group is insoluble in an aqueous solution of a polyvalent anion salt such as a sulfate or hydrogen phosphate, and is a free-flowing cationic with excellent storage stability by polymerizing while stirring in the presence of a dispersant. A water-soluble polymer dispersion can be produced. The dispersion has various properties as described in claim 5. The dispersant according to claim 5 is a cationic monomer selected from dimethylaminoethyl (meth) acrylate acid salt or methylated product, dimethylaminopropyl (meth) acrylamide acid salt or methylated product, dimethyldiallylammonium salt and mixtures thereof. 50 to
The most common are water-soluble (co) polymers containing 100 mol% and the balance being acrylamide (including mixtures thereof of course). Examples of the dispersion medium include aqueous solutions of salts such as ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, sodium dihydrogen phosphate and ammonium dihydrogen phosphate.

As the polymerization initiator used in the synthesis of the dispersant and the cationic water-soluble polymer dispersion, a known radical generator is used, and a redox type or azo type radical generator is used. PH during the synthesis, that is, during the polymerization is acidic so that the cation monomer is not denatured, and the initiation temperature is selected at an appropriate temperature at which the initiator functions. When it is used as a filler retention improver, it is added as an aqueous solution having a concentration of the cationic water-soluble polymer of about 0.01 to 0.5% by weight. If an aluminum salt is used together at this time, the pH buffering action or the like may occur. The effect is improved. The combination with a low molecular weight cation, which is a general papermaking technique, for example, the combined use of a dimethyldiallylammonium chloride polymer and a polyamine / epichlorohydrin condensate can be similarly applied to the present invention.

[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) Stirrer, thermometer, reflux cooling cup,
Into a 1-liter five-necked separable flask equipped with a nitrogen inlet tube, 4.2 g of polyacryloyloxyethyltrimethylammonium chloride as a dispersant and 84.0 g of ammonium sulfate as a precipitant were placed, and ion-exchanged water 3
03.2 g was added and dissolved. Acryloyloxyethylbenzyldimethylammonium chloride 5
2.08 g (30 mol%), acryloyloxyethyltrimethylammonium chloride 24.93 g (20 mol%) and acrylamide 22.87 g (50 mol%) were charged, and nitrogen substitution was performed while heating to 50 ° C. 2,2′-azobis (2
-2.0 g of a 1% aqueous solution of amidinopropane) hydrochloride was added and polymerized under stirring at 50 ° C for 10 hours to obtain a fine particle polymer dispersed in the salt aqueous solution. When the viscosity of this reaction liquid was measured with a B8-H type viscometer manufactured by Tokyo Keiki Co., Ltd., it was 1500 CP. 21 g in this reaction solution
When ammonium sulfate was added and dissolved, and the viscosity was measured in the same manner, it was 350 CP. When observed with an optical microscope, the average particle size was 15 microns. This solution is referred to as Sample 1 except that the monomer composition is changed.
Samples 2 to 4 were synthesized by the same synthesis method as in. On the other hand, samples 5 to 9 were synthesized by aqueous solution polymerization. Table 1 shows a list of each synthesized sample. The intrinsic viscosity, which is an index of the molecular weight of the polymer, was measured in a 2 wt% concentration ammonium sulfate aqueous solution.

[0010]

[Table-1]

(Example-1) The results of measuring the total yield and the filler yield by the Brit type dynamic jar tester are shown in Table 2. The stocks used in the test were talc 900ppm, kaolin 500ppm, pulp 4000.
It is a medium quality paper of ppm, PH 6.0 and CSF 300 ml.

[Table-2]

[0012]

EFFECT OF THE INVENTION The terpolymer used in the present invention has a clear superiority in the effect of improving the filler yield and the total yield, as compared with the binary copolymer as a comparative sample. It can be said that the existence of such a performance difference in the paper manufacturing industry is a technology that could not have been predicted based on the experience so far.

Claims (5)

[Claims] 1. A filler retention aid comprising an acrylic cationic water-soluble polymer containing 5 mol% or more of an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit, respectively. 2. The filler retention improver according to claim 1, which is a copolymer of an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit. 3. The total sum of the cationic monomer structural units is 1.
It is 5 mol% or more, The filler yield improvement agent of Claim 1 characterized by the above-mentioned. 4. The filler retention improver according to claim 1, which has an intrinsic viscosity of 10 dl / g or more in an ammonium sulfate aqueous solution having a concentration of 2% by weight. 5. An acrylic cationic water-soluble polymer,
A polymer dispersion in a polyvalent anion salt aqueous solution containing a dispersant comprising a polyelectrolyte, wherein the dispersion is (1)
The concentration of the cationic water-soluble polymer in the dispersion is 5% by weight or more (2) The average particle size of the cationic water-soluble polymer in the dispersion is 0.1 to 150 microns (3) The viscosity is 10 to 3000 CP at room temperature (4) the salt concentration in the dispersion is 15 wt% or more and the saturation concentration or less (5) the dispersant concentration in the dispersion is 1 with respect to the cationic water-soluble polymer. % To 15% by weight.
The filler retention improver according to any one of 5 to 5.