JPH03104998A - Sizing method - Google Patents

Abstract

PURPOSE: To carry out sizing of CaCO3 -contg. paper without decomposition of CaCO3 by mixing paper pulp with a specified aq. colloidal soln. under specified conditions before addition of a resin sizing dispersion to the paper pulp. CONSTITUTION: First, an aq. colloidal soln. of homogeneous aluminum hydroxide with pH of 6-8 contg. 0.1-50 gel of aluminum hydroxide is prepared. Further, the colloidal soln. is mixed with paper pulp under the turbulent condition during or immediately after formation of the colloidal soln. Finally, after a resin sizing dispersion is added to the mixture, paper is made. It is preferable to prepare the above colloidal soln. by mixing an aq. soln. contg. 15-20 g/l of an acidic reactive Al salt with an aq. soln. contg. 10-20 g/l of an alkaline reactive substance at the stoichiometric proportions under the turbulent condition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method for sizing calcium carbonate-containing paper using a resin sizing dispersion.

BACKGROUND OF THE INVENTION Sizing calcium carbonate-containing papers using resin-sized dispersions presents considerable practical difficulties, due to acidic reactions such as aluminum sulfate commonly used to precipitate and fix resin sizes. This is because solutions of aluminum salts react with calcium carbonate in an undesirable manner, causing the salts to decompose.

To practically prevent such undesirable reactions,
Various measures have been taken in the past.

Examples of such measures include the following methods: (1) As a substitute for aluminum i-acid, basic polyhydroxyaluminum chloride with relatively weak acidic reactivity,
For example, the compounds described in European Patent No. 0.068,812 and Saichistrian Patent No. 356.511, or basic polyhydroxyaluminum chloride or hydrates thereof, such as the European Patent No. 356.511, for example, 0.
1 2 5.2 2 Method of using the compound described in specification 1, (2) adding a water-soluble aluminate, preferably sodium aluminate, to an aqueous fiber suspension to be subjected to a sizing treatment;
until the pH is at least 9, and then lower the pH of the system to 4.0 using, for example, sulfuric acid or aluminum sulfate.
5 (U.S. Patent Nos. 3 and 5)
(3) A pulp sizing agent containing an alkali metal salt of aluminate and a resin size is mixed with a fiber suspension containing calcium carbonate under neutral conditions, and then an organic acid or an inorganic acid Activation treatment with acids and/or acidic reactive salts, such as aluminum sulfate (see European Patent No. 0.112.525); (4) colophonic dispersions containing basic polyhydroxyaluminum chloride; (5) using a liquid-based sizing agent (see European Patent No. 0.200.002), (5) adding the diluted resin-sized dispersion to the paper pulp; method by mixing with a dilute solution of aluminum sulfate or polyhydroxyammonium chloride.

The problem with these methods is that in each case the calcium carbonate-containing fiber suspension comes into contact with an acidic reactive compound, which is an acid or an acidic reactive salt, so that the calcium carbonate decomposes.

Furthermore, practically, it is possible to add the acidic reactive aluminum compound to the papermaking pulp containing calcium carbonate and the resin size dispersion, before, during or immediately after the addition of the acidic reactive aluminum compound, from the addition position of the aluminum compound or before and after the addition position. It is also known to neutralize the aluminum compounds by adding sodium aluminate solutions. By using this method, the sizing can be carried out in a neutral pH range, so it is possible to reduce the decomposition of calcium carbonate, but it cannot be completely suppressed.

Aluminum hydroxide form obtained by precipitation from aluminum sulfate solution with sodium hydroxide solution or aluminate solution, which can be used on a laboratory scale with the addition of the aluminum component used for resin size precipitation and fixation. Attempts to do so were unsuccessful, as the aluminum hydroxide prepared by such precipitation methods is a very bulky gelatinous material, making it extremely difficult to disperse into paper pulp. This is due to this.

Additionally, the aluminum hydroxide prepared by this precipitation method is heterogeneous and contains alkaline reactive components that interfere with sizing. Furthermore, since aluminum hydroxide precipitates of this type ripen rapidly, their sizing action is hindered.

Problems to be Solved by the Invention The present invention solves the above-mentioned conventional problems and provides a method for sizing paper containing calcium carbonate using a resin size separation solution without decomposing calcium carbonate. It was created to provide the following.

Means for solving the problem, that is, the present invention provides (i) aluminum hydroxide
preparing an aqueous colloidal solution of homogeneous aluminum hydroxide containing 50 g/l and having a pH of 6 to 8; (ii) adding the colloidal solution to a papermaking pulp or resin size dispersion during or immediately after the preparation of the colloidal solution; A method for sizing paper containing calcium carbonate using a resin sizing dispersion comprising mixing under turbulent conditions with a resin sizing dispersion.

The colloidal solution of aluminum hydroxide contains 1 to 40 g/4, preferably 15 to 20 g of acidic reactive aluminum salt.
/l of an aqueous solution containing at least one alkaline reactive substance in a stoichiometric ratio with an aqueous solution containing 1-50 g/l, preferably 10-20 g/l, under turbulent flow conditions. Preferably, it is prepared by mixing at However, 1 acidic reactive aluminum salt
An aqueous solution containing up to 40 g/l, preferably 15 to 20 g/l, may be catalytically passed over an OH type anion exchanger.

Suitable acidic reactive aluminum salts include aluminum sulfate, aluminum chloride, and dihydrogen phosphate. minium, formula AI2, (○H), . CQ3. - (wherein n is a number greater than 1) basic polyhydroxyaluminum chloride, formula AI2, (OH). (S04)T
3a-ml/■ (in the formula, n represents a number larger than l) basic polyhydroxyaluminum sulfate,
Or hydrates thereof, etc. are exemplified.

Examples of alkaline reactive substances include inorganic substances such as alkali metal hydroxides, sodium aluminate, sodium silicate, or potassium silicate, such as mixtures of sodium aluminate and sodium or potassium silicate, and organic bases. . Suitable organic bases include primary, secondary or tertiary alkylamines, such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine or triethylamine, quaternary alkylammonium hydroxides, such as tetramethylammonium hydroxide or tetraethylamine. Examples include ammonium hydroxide and the like, or mono-, di- or tri-alkanolamines such as monoethanolamine, diethanolamine or triethanolamine.

The pH of the colloidal solution of aluminum hydroxide is, as mentioned above, 6-8, preferably 6.5-7.5, especially 6.8.
~7.2. The colloidal solution has a flow rate of 2 to 10 m/
Preferably, it is mixed vigorously with the paper pulp under conditions of s.

Aqueous solutions of acidic reactive aluminum salts or aqueous solutions of alkaline reactive substances are prepared by diluting these relatively concentrated solutions, preferably with paper machine clear water, under turbulent flow conditions, for example using a stationary mixer. It can be prepared by:

Cationic fixatives, such as cationic "RESIAFIX" (a product obtained by condensation of dicyandiamide and formaldehyde in the presence of ammonium chloride, with a solids content of 50% by weight and a pH of 3 ~4 commercially available products), polyethyleneimine,
polyacrylamide, shrimp chlorohydrin resin or cationic starch, and/or retentive
on agent), such as a silicic acid sol, can be added to the aqueous solution of the acidic reactive aluminum salt. Addition of cationic compounds results in homogeneous aluminum hydroxide, which has cationic properties and therefore not only adsorbs resin-sized particles, but also adsorbs and removes interfering substances. When active silicic acid is mixed with homogeneous aluminum hydroxide, substances that interfere with sizing are removed.

This can be done, for example, by reacting an aluminum sulfate solution with a solution of a mixture of sodium aluminate and sodium or potassium silicate, a solution of a mixture of sodium hydroxide and sodium or potassium silicate, or a solution of sodium silicate under turbulent conditions. It can be done.

An aqueous colloidal solution of homogeneous aluminum hydroxide may be mixed with the paper pulp for 0.2 to 20 seconds upstream of a flow box, or the colloidal solution may be mixed with a resin size dispersion and the mixture may be added to the paper pulp.

If desired, the mixing of the starting solutions may take place directly in the papermaking pulp where turbulent conditions prevail.

Preferably, the homogeneous aqueous colloidal solution of aluminum hydroxide has a concentration of 0% aluminum oxide relative to paper pulp.
．． Preferably, it is used in a proportion of 5 to 1.5% by weight.

It is preferable to use the tall resin or colophony dispersion in an amount of 0.2 to 3 ffi, calculated as absolute dry resin, based on the paper pulp. The resin size dispersion can be mixed upstream of the paper machine with the aforementioned cationic fixing agents and/or retention agents.

Commercially available Thor resin or colophony dispersions have a solids content of 30-40% by weight, a pH of 6-8, and a free resin content of 75-97% by weight. A particularly preferred resin size dispersion is the product sold under the trademark "REsopLArs". This product is a tall peripole dispersion fortified with 7-8% by weight of hepatomaric acid and is a protective Contains casein as a colloid, has a pH of 6,
The solid content is 30% by weight, and the average particle size of the contained particles is 0.65 to 1 μm.

The resin size dispersion is typically added continuously to the paper pulp either upstream or downstream of the mixer pump;
The amount used is 0.2 to 1% by weight, calculated as absolute dry resin, based on the paper pulp.

The invention is further illustrated by the following examples.

Example 1 An aluminum sulfate solution containing 8% by weight of aluminum (calculated as aluminum oxide), commercially available from Ablique Uetichon (Switzerland), was fed to a stationary mixer at a flow rate of 4012/h using a reciprocating pump. and mixed in the mixer with water, which is fed at a flow rate of 2.500 Q/h. A sodium aluminate solution with a density of 1.55 containing 25.5% by weight of aluminum in terms of aluminum oxide [Petromontane (Austria)]
Commercial product 1 (Vienna) is fed at a flow rate of 2212/h to a stationary mixer using another reciprocating pump and mixed in the mixer with water, which is fed at a flow rate of 1,000 ff/h. The dilute solution of aluminum sulfate and the dilute solution of sodium aluminate thus prepared are uniformly mixed in a T-mixer.

The flow rates of the aluminum sulfate solution and the sodium aluminate solution in the mixer are 2.7 m/s and 4.2 m/s, respectively. The pH of the colloidal solution of homogeneous aluminum hydroxide thus prepared is 6.9 and the Reynolds number is 25,000. Immediately after preparation, this colloidal solution is added to the diluted pulp 0.5 m upstream of the pressure sorter.

The output of the paper machine is 3. 500 kg/h.

The fiber furnish is made from 70% by weight bleached short fiber pulp and 30% by weight bleached long fiber pulp. 12 parts by weight of kaolin and 7 parts by weight of carbonic acid are used as fillers. "Resoplan" 60β
Mix with the paper pulp upstream of the mixer pump at a flow rate of /h.

The pH inside the flow box is 7.1, and the water hardness of Backwater I after 3 hours of the experiment is 100 dH. The area weight of the obtained paper is 1009/II1'', and the ignition residue at the ignition temperature of 575°C is 19%.The cup (Cobb) 60 value of the finally obtained paper is the same as that of the upper surface. 18 g/m'' on both sieve surfaces, and the ink penetration time in the ink flotation test is 52 minutes.

Example 2 Waste paper that has been subjected to deinking treatment (waste paper that has not been subjected to acidification treatment using sulfuric acid and has a pulp consistency of 5.4%)
370 g are diluted with tap water to a pulp consistency of 1%, 1.5% by weight of aluminum sulfate are added and the mixture is stored under stirring in storage container I. Injection capacity of fiber suspension in container 1: 2.0+2/min
into the storage container 2 using a laboratory pump.

During this pumping, (a) mixture A of Resopran and Resia 7ix and (b) mixture B of aluminum sulfate and sodium aluminate are mixed with the fiber suspension.

Mixture A is prepared as follows: Resopran and Resiafix are diluted with water to a solids content of 50 g/l and 1.5 g/l, respectively, and these dilutions are mixed using a stationary mixer. Mix by volume. The rate of addition of mixture A to the fiber suspension was 40
mQ/min.

Mixture B is prepared as follows: 17% by weight aluminum, calculated as aluminum oxide.
A commercially available aqueous aluminum sulfate solution containing (1.4 5
6 g/l) 50 parts by volume and 50 parts by volume of a sodium aluminate aqueous solution (2.26 g/12) containing 25% by weight of aluminum in terms of aluminum oxide.
Mix vigorously using a mixer and mix the mixture with the fiber suspension immediately after mixing at a flow rate of 200 mQ/min.

Starting from the fiber suspension in storage container 2 containing mixtures A and B, sheets are prepared using a Ketjen rapid sheet molding machine. The area 'm of the obtained sheet was 84g/m
”. The cup 15 value of the final sheet is 6.
4 g/m'. The anionic charge, hardness and pH of potassium polyvinyl sulfate determined on the filtrate are 8.2 .mu.eq/l% 16.dH and 7.5, respectively.

Example 3 150 parts by volume of the aluminum sulfate solution used in Example 2 and sodium silicate (NaO:Sioz=l:3:
3) in an aqueous solution containing 8.093 g/4 (density 1.3
5) The same operation as in Example 2 was performed except that 50 parts by volume were used to prepare mixture B.

The area weight of the sheet obtained is 83 g/II+''.

The cup l5 value of the final sheet was 96g/m2
It is. The anionic charge, hardness and pH of potassium polyvinyl sulfate measured on the filtrate were each 6.2 μe.
q. #! , l 6.5°dH and 7.6.

Example 4 Aqueous solution 1 containing 1.456 g/l of aluminum sulfate and 1.3 g/l of Resiafix used in Example 2
The same operation as in Example 2 was performed except that Mixture B was prepared using 50 parts by volume and 50 parts by volume of the sodium aluminate aqueous solution used in Example 2.

The area weight of the sheet obtained is 80 g/m''.

The cup l5 value of the final sheet was 54 g/lT.
+2. The anionic charge, hardness and pH of potassium polyvinyl sulfate measured on the filtrate are each 6.1.
,ueq. /l,1 3.5°dH and 7.4.

Effects of the Invention According to the present invention, when sizing calcium carbonate-containing paper using a resin size dispersion, the calcium carbonate is effectively decomposed by the acidic reactive aluminum salt solution used for precipitation and fixation of the resin size. can be prevented.

Procedural amendment report! ! 4 November 22nd, 2015 Ig. 2 years Patent Consultant No. 1280112. Issue 1
71 name sizing method 3, relationship with the case of the person making the amendment Patent applicant 4. agent

Claims (1)

[Claims] 1. (i) preparing a homogeneous aqueous colloidal solution of aluminum hydroxide containing 0.1 to 50 g/l of aluminum hydroxide and having a pH of 6 to 8; (ii) preparing a colloidal solution of the colloidal solution; A method for sizing calcium carbonate-containing paper using a resin size dispersion, comprising mixing the colloidal solution with a papermaking pulp or a resin size dispersion under turbulent conditions during or immediately after preparation. 2. Prepare an aqueous solution containing 1 to 40 g/l, preferably 15 to 20 g/l of an acidic reactive aluminum salt, and add 1 to 40 g/l of at least one alkaline reactive substance to the aqueous solution.
2. Process according to claim 1, characterized in that the colloidal solution of aluminum hydroxide is prepared by mixing under turbulent conditions in stoichiometric proportions with an aqueous solution containing 50 g/l, preferably 10-20 g/l. 3. A colloidal solution of aluminum hydroxide is prepared by passing an aqueous solution containing 1 to 40 g/l, preferably 15 to 20 g/l, of an acidic reactive aluminum salt over an OH type anion exchanger. Method described. 4. As acidic reactive aluminum salts, aluminum sulfate, aluminum chloride, aluminum dihydrogen phosphate, formula Al
_n(OH)_mCl_3_n_-_m (where n is 1
a basic polyhydroxyaluminum chloride of the formula Al_n(OH)_m(SO
_4) _(_3_n_-_m_)_/_2 (wherein n is a number larger than 1) A basic polyhydroxyaluminum sulfate or a hydrate thereof is used according to claim 2 or 3. the method of. 5. As alkaline reactive substances, inorganic substances such as alkali metal hydroxides, sodium aluminates, sodium silicates or potassium silicates, organic bases such as primary, secondary or tertiary alkyl amines such as methylamine, ethylamine, dimethylamine, diethylamine,
quaternary alkylammonium hydroxides such as trimethylamine or triethylamine, such as tetramethylammonium hydroxide or tetraethylammonium hydroxide, or mono-, di- or tri-alkanolamines such as monoethanolamine, diethanolamine or triethanolamine 3. The method according to claim 2, wherein 6. The method according to claim 5, wherein a mixture of sodium aluminate and sodium or potassium silicate is used as the alkaline reactive substance. 7. Aqueous solutions of acidic reactive aluminum salts or aqueous solutions of alkaline reactive substances are mixed at relatively high concentrations, preferably with paper machine clear water, under turbulent conditions, e.g. using a stationary mixer. 7. A method according to any of claims 2 to 6, wherein the method is prepared by dilution. 8. Claims 1 to 7, wherein the cationic fixing agent and/or retention agent is added to the aqueous solution of the acidic reactive aluminum salt.
Any method described. 9. A homogeneous aqueous colloidal solution of aluminum hydroxide is mixed with paper pulp upstream of the flow box at a concentration of 0.2 to 20%.
9. A method according to any one of claims 1 to 8, wherein the mixing is performed for seconds. 10. A method according to any one of claims 1 to 8, wherein the homogeneous aqueous colloidal solution of aluminum hydroxide is mixed with the resin size dispersion and the mixture is added to the papermaking pulp. 11. An aqueous colloidal solution of homogeneous aluminum hydroxide is converted into aluminum oxide and has a 0.
11. The method according to claim 1, wherein 5 to 1.5% by weight is used. 12. 0.2 to 3% by weight of Thor resin or colophony dispersion based on paper pulp, calculated as absolute dry resin.
12. The method according to claim 1, wherein the resin size dispersion is used in a proportion of . 13. Claim 1, wherein the resin size dispersion is mixed with a cationic fixing agent and/or retention agent upstream of the paper machine.
The method described in 2.