JP3092694B2 - Filler retention improver - Google Patents

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 comprising a cationic polymer. The filler retention enhancer of the present invention improves the quality of paper and prevents the flow of raw materials, The purpose is to extend the life.

[0002]

2. Description of the Related Art Various filler retention improvers have been proposed. For example, Hoffmann decomposition product of polyacrylamide, Mannich modified product of polyacrylamide, and acrylic filler retention improver are disclosed in JP-A-61-639.
No. 7, JP-A-61-6398 and the like are known to be effective. Many amphoteric methacrylates are known as papermaking chemicals.
Further, as a sludge dewatering agent, a cationic copolymer comprising an acryloyloxyethyldimethylbenzylammonium salt structural unit, an acryloyloxyethyltrimethylammonium salt structural unit and an acrylamide structural unit (JP-A-62-262799) is known.

The effect of the filler retention improver is to reduce the difference between the front and back sides of the paper as described above, or to average the composition distribution in the thickness direction of the paper layer to produce high-quality paper, and to reduce the flow of raw materials. This has the advantage that it is possible to reduce costs by reducing the cost and to reduce the stock density, so that it is easy to mass-produce paper of a certain quality by controlling the variation of the formed paper. Also, recent machine wires generally use plastic wires instead of bronze, and have the disadvantage that the characteristics of the plastic wires are that they are significantly worn by wire passing fillers. It is self-evident that the filler retention improver can reduce the amount of filler passing through the wire, and of course has the effect of extending the life of the wire. Although such effects have been recognized with conventional chemicals, the conventional chemicals are insufficient for the above-mentioned purpose, and new chemicals have been demanded.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to produce a high quality paper by using a filler retention improver to average the composition distribution in the thickness direction of the paper layer. In addition, it is possible to reduce the cost by preventing the flow of raw materials, and to reduce the stock density, which makes it easy to mass-produce paper of a certain quality by controlling the variation of the formed paper. It is an object of the present invention to provide a papermaking chemical which can provide an advantage or extend the life of a plastic wire.

[0005]

Means for Solving the Problems The invention of claim 1 is (A)
Acryloyloxyethyl dimethylbenzylammonium salt, (B) acryloyloxyethyltrimethylammonium salt, and (C) acrylamide were each 5 mol%.
And a monomer mixture containing (A) + (B) in an amount of 15 mol% or more in an aqueous polyvalent anion salt solution containing a dispersant comprising a polymer electrolyte. Intrinsic viscosity of 10 dl in aqueous solution of ammonium sulfate
/ G or more of a water-soluble cationic polymer ,
(1) the concentration of the water-soluble cationic polymer in the dispersion is 5% by weight or more; (2) the average particle size of the water-soluble cationic polymer in the dispersion is 0.1 to 150 microns; The viscosity of the dispersion is 10 to 3000 mpas · s at room temperature. (4) The salt concentration in the dispersion is not less than 15% by weight and not more than the saturation concentration. (5) The concentration of the dispersant in the dispersion is water-soluble.
A filler retention improver comprising a polymer dispersion, wherein the amount is 1 to 15% by weight based on the on-polymer . The water-soluble cationic polymer which is the filler retention aid of the present invention is
A monomer mixture containing (A), (B) and (C) in an amount of 5 mol% or more is dispersion-polymerized in an aqueous polyvalent anion salt solution containing a polymer electrolyte, and further (A) + (B) It is necessary that the total molar ratio of the cationic monomers is 15 mol% or more. In other words, if the amount of the cationic group is less than this, the filler retention effect will be reduced, the raw material will be largely lost, and the difference between the front and back sides of the paper will be large, making it impossible to produce high quality paper. Further, the intrinsic viscosity of the water-soluble cationic polymer of the present invention is 10 dl / g or more. Intrinsic viscosity is an index of the molecular weight, but when the molecular weight is low, the cohesive strength is weak, the filler retention effect is low, and the front-back difference tends to be large.

A cationic polymer electrolyte 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 due to its unique synergistic effect. Stronger cohesive force than cationic polymer coagulant. In addition, this functional group is insoluble in aqueous solutions of polyvalent anions such as sulfates and phosphates, and is polymerized with stirring in the presence of a dispersant to give a free-flowing water-soluble cation with excellent storage stability. A polymer dispersion can be produced. This dispersion has (1) a concentration of the water-soluble cationic polymer in the dispersion of 5% by weight or more, and (2) an average particle size of the water-soluble cationic polymer in the dispersion of 0.1 to 150 μm. Yes (3) The viscosity of the dispersion is 10 to 30 at room temperature
(4) When the salt concentration in the dispersion is 15
(5) It has various physical properties such that the concentration of the dispersant in the dispersion is 1 to 15% by weight with respect to the water-soluble cationic polymer . The dispersing agent comprising a polymer electrolyte coexisting during the dispersion polymerization may be dimethylaminoethyl (meth) acrylates or dimethylaminopropyl (meth) acrylamides, each of which is an inorganic or organic acid salt, or a quaternary ammonium salt of methyl halide. A homopolymer or a copolymer of a salt, a homopolymer of a dimethyldiallylammonium salt or a copolymer with the cationic monomer, or a cationic monomer containing one or more of these cationic monomers; Those having a molar ratio of at least 50 mol% and copolymerized with acrylamide are preferred. Salts of the aqueous polyvalent anion salt used as a dispersion medium during dispersion polymerization include ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, sodium dihydrogen phosphate, ammonium dihydrogen phosphate and the like.

As the polymerization initiator used for the synthesis of the dispersant and the synthesis of the cationic water-soluble polymer dispersion, a known radical generator is used, and a redox-based or azo-based radical generator is used. During the synthesis, that is, during the polymerization, the PH is acidic so that the cationic monomer does not deteriorate, and the starting temperature is selected to be an appropriate temperature at which the initiator functions. When used as a filler retention improver, the concentration of the cationic water-soluble polymer is added as an aqueous solution having a concentration of about 0.01 to 0.5% by weight. The effect is improved. A combination with a low molecular weight cation, which is a general papermaking technique, for example, a combination of a dimethyldiallylammonium chloride polymer and a polyamine / epichlorohydrin condensate can be similarly applied in 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 condenser,
In a 1-liter five-neck separable flask equipped with a nitrogen inlet tube, 4.2 g of polyacryloyloxyethyltrimethylammonium chloride as a dispersing agent and 84.0 g of ammonium sulfate as a precipitating agent were placed.
03.2 g was added and dissolved. This is followed by 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 the atmosphere was replaced with nitrogen while heating to 50 ° C. To this, 2,2′-azobis (2
After adding 2.0 g of a 1% aqueous solution of (amidinopropane) hydrochloride and polymerizing at 50 ° C. for 10 hours with stirring, a polymer of fine particles dispersed in the aqueous salt solution was obtained. The viscosity of this reaction solution was 1500 CP when measured with a B8-H type viscometer manufactured by Tokyo Keiki Co., Ltd. 21 g to this reaction solution
Was added and dissolved, and the viscosity was measured in the same manner. In addition, when observed with an optical microscope, the average particle size was 15 microns. This liquid was referred to as Sample 1, and Sample 1 was used except for changing the monomer composition.
Samples 2 to 4 were synthesized by the same synthesis method as described above. On the other hand, Samples 5 to 9 were synthesized by aqueous solution polymerization. Table 1 shows a list of the synthesized samples. The intrinsic viscosity, which is an index of the molecular weight of the polymer, was measured in a 2% by weight aqueous solution of ammonium sulfate.

[0010]

[Table-1]

Example 1 Table 2 shows the results of measuring the total yield and the filler yield using a brit type dynamic jar tester. The stock used for the test was talc 900 ppm, kaolin 500 ppm, and pulp 4000.
ppm, pH 6.0, CSF 300 ml medium quality paper.

[Table-2]

[0012]

The terpolymer used in the present invention has a clear advantage over the comparative binary copolymer in the effect of improving the filler retention and the total retention. The existence of such a performance difference in the papermaking industry can be said to be a technology that could not be expected in the past experience.

Claims (1)

(57) [Claims] 1. Acryloyloxyethyldimethylbenzylammonium salt (A), acryloyloxyethyltrimethylammonium salt (B) and acrylamide (C) each containing at least 5 mol%, and (A) + (B) being 1
A monomer mixture of 5 mol% or more is dispersion-polymerized in an aqueous solution of a polyvalent anion salt containing a dispersant comprising a polymer electrolyte, and has an intrinsic viscosity of 10 dl / g or more in a 2% by weight aqueous solution of ammonium sulfate. Some water-soluble cationic
A polymer, (1) a water-soluble cationic polymer concentration in the dispersion is not less 5 wt% or more (2) average particle diameter of the water-soluble cationic polymer in the dispersion is 0.1 to 150 (3) the viscosity of the dispersion is 10 to 300 at room temperature
(4) The salt concentration in the dispersion is not less than 15% by weight and not more than the saturation concentration. (5) The dispersant concentration in the dispersion is 1 to 15% by weight based on the cationic water-soluble polymer.
A filler retention improver comprising a polymer dispersion.