JPS61133218A - Production of loading material for paper - Google Patents

Abstract

PURPOSE:To obtain the titled material made up of particles of specific size, useful for improving white paper non-transparency and ink-acceptability, by mixing acid catalyst and an aminoaldehyde initial condensate with its urea component and/or formaldehyde one substituted in each specific condition. CONSTITUTION:(A) An aminoaldehyde initial condensate prepared from 1.0pt. by mol of urea and 1.0-2.0pts. by mol of formaldehyde with <=50mol% of the former substituted by cyanamide or dicyanamide derivative and/or <=50mol% of the latter substituted by alkylaldehyde or alkenylaldehyde and (B) an acid catalyst (e.g., sulfuric acid) are mixed at pref. 20-90 deg.C followed by solidification at a pH<=3.0 pref. within 50sec. to make the average primary particle size of the resultant solid 0.15-0.50mu, thus obtaining the objective loading material for paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a paper filler comprising crosslinked aminoaldehyde polymer particles. The present invention provides fillers useful for improving paper blank opacity, ink receptivity during offset printing, and post-print opacity.

[Conventional technology]

Cross-linked urea-formaldehyde polymer particles with a BET specific surface area of 5 to 100 tri/f obtained by mixing and solidifying an initial condensate consisting of 1.0 mole part of urine i and 1.0 to 260 mole parts of formaldehyde and an acidic aqueous solution are It is already known that it is useful as a filler for improving whiteness and white paper opacity. (Japanese Patent Publication No. 51-23601. Japanese Patent Publication No. 54-135893') [Problems to be solved by the invention] Newspaper rolls and other printing paper tend to be lighter in order to save resources and streamline transportation. This is achieved by making the paper thinner, but bleed through becomes an obstacle. Show-through is caused by a decrease in the opacity of the paper itself (hereinafter referred to as white paper opacity), and the printed ink penetrates into the paper and becomes visible from the back side (hereinafter, the degree to which this is prevented is determined by printing). There is bleeding (referred to as post-opacity). Both physical properties are important physical properties for printing paper, as the printed image on the back is visible from the front, making the front side difficult to read. In offset printing, ink receptivity is also an important physical property in order to obtain a uniform printing surface without printing unevenness.

The above-mentioned known crosslinked urea formaldehyde polymer particles are not necessarily sufficient in these effects. In particular, the effects of improving post-print opacity and ink receptivity are insufficient.

Reducing the weight of newspaper rolls is an important issue, and the conventional basis weight is 4.
9. Currently 46. C1/1rt is the mainstream, and 43. Of/d is being considered.

In this case, the main performances required for one paper are whiteness, white paper opacity, post-print opacity, and ink receptivity, and especially for the first three, the basis weight is 43. When it comes to about Oy/at, it becomes very difficult to improve it by 1%. Basis weight 46
．． ON/rrt newspaper rolls are possible by using the crosslinked urea formaldehyde polymer particles described above as filler.

43.Of/lrl, it is no longer possible to use such a filler because the above-mentioned performance becomes insufficient.

Therefore, it is desired to develop a paper filler with even better performance.

In view of this situation, the present invention improves the blank opacity of paper, the opacity after printing, and the ink receptivity.

43. It is an object of the present invention to provide a filler for paper making that enables even Of/lri newspaper rolls.

[Means for solving problems]

As a result of intensive research in order to obtain lightweight printing paper, the inventors of the present invention have found that a part of the urea component in cross-linked urea-formaldehyde polymer particles is replaced with cyanamide or a dicyanamide derivative, or a part of the formaldehyde component is replaced with an alkyl aldehyde or alkenyl derivative. Cross-linked aminoaldehyde polymer particles of a specific particle size obtained by substitution with aldehyde provide white paper opacity of paper.

The present invention was completed based on the discovery that the present invention has the effect of significantly improving ink receptivity during offset printing and opacity after printing.

That is, the present invention uses 1.0 mole part of urea and 1.0 mole part of formaldehyde.
0 to 2.0 mole parts, and 50 mole% or less of the urea is substituted with cyanamide or dicyanamide,
and an acid catalyst is mixed with an aminoaldehyde initial condensate in which not more than 50 mol% of the formaldehyde is substituted with an alkyl aldehyde or alkenyl aldehyde, or either the urea or the formaldehyde is substituted with the above-mentioned one. The average primary particle size is 0.15 to 0.50, and is solidified at pH 3.0 or lower.
This is a method for producing μ paper filler.

The filler produced according to the present invention has an average primary particle size of 0.15
~0.5μ, typically 0.17-0.35μ.

If the average primary particle size is less than 0.15μ, the effect of improving white paper opacity is insufficient, and if it exceeds 0.5μ, the effect of improving opacity after printing is insufficient.

Here, the average primary particle size and average secondary particle size have the following meanings. That is, the filler in the present invention is an agglomeration of individual fine particles. Therefore, the average diameter of individual particles is referred to as the average missing particle diameter, and the average diameter of aggregated particles is referred to as the average secondary particle diameter. Usually, the former is measured using an electron micrograph, and the latter is measured using a Coulter counter.

In the present invention, the cross-linked aminoaldehyde polymer particles are prepared by replacing a part of the urea component of cross-linked urea-formaldehyde polymer particles with cyanamide or a sifuanamide derivative, or by replacing a part of the formaldehyde with an alkyl aldehyde or an alkyl aldehyde. The main idea is to obtain it by substitution. Here, cyanamide or dicyanamide derivatives include dicyandiamide and thiourea.

These include guanidine, acetoguanamine, benzoguanamine, spiroguanamine, phenylacetoguanamine, melamine, melam, melem, amelide, amerine, etc., and the reason why the amount of urea substitution in these was limited to 50 mol% or less is as follows.
This is because if the amount of substitution exceeds 50 mol%, the whiteness of the paper will decrease. The preferred amount of substitution is 5 to 40 mol%, and preferred derivatives are dicyandiamide, guanidine, acetoguanidine, melamine, thiourea and the like.

Further, the alkyl aldehyde or alkyl aldehyde includes acetaldehyde, inobutyraldehyde, n-butyraldehyde, acrolein, crotonaldehyde, and the like. The reason why the formaldehyde substitution amount is limited to 50 mol % or less is that if the substitution amount exceeds 50 mol %, the whiteness of the paper decreases as described above. The preferred amount of substitution is 5 to 40 mol%, and preferred aldehydes include isobutyraldehyde and n-butyraldehyde.

Cyanamide or dicyanamide derivative moiety group of urea (
Alkyl aldehyde or alkenyl aldehyde partial substitution group of formaldehyde (hereinafter referred to as total aldehyde compound) per 1.0 mole part of formaldehyde (hereinafter referred to as total amine compound)
The reason why it is limited to 1.0 to 2.0 parts by mole is that if the total aldehyde compound is less than 1.0 parts by mole, the average primary particle size of the crosslinked aminoaldehyde polymer particles obtained will be larger than 0.5μ, The reason is that the opacity of the printing paper decreases after printing. Furthermore, if the total amount of aldehyde compounds exceeds 2.0 moles, the yield of crosslinkable aminoaldehyde polymer particles (hereinafter referred to as yield) becomes small based on the total weight of all amine compounds and all aldehyde compounds.

The reaction to obtain an aminoaldehyde initial condensate (hereinafter referred to as initial condensate) from all amine compounds and all aldehyde compounds is carried out using an aqueous solution with a concentration of 20 to 60% by weight at a pH of 3 to 10 and a reaction temperature of 20 to 100°C. The liquid viscosity at 25° C. is measured from 10 to 200 centipoise using a Purckfield viscometer.

Also, for long-term preservation of the initial condensate, use hydrochloric acid or nitric acid.

Acids such as sulfuric acid, formic acid, acetic acid, or caustic soda, caustic potash,
The pH can also be adjusted within a range of 6 to 8 using an alkali such as ammonia, ethanolamine, inclopanolamine, or the like.

As a step after obtaining the initial condensate, the initial condensate is mixed with an acid catalyst for reaction solidification while stirring. A suitable acid catalyst for this purpose is sulfuric acid.

Mineral acids such as phosphoric acid, hydrochloric acid, nitric acid; organic acids such as formic acid, oxalic acid, maleic acid, succinic acid and chloroic acid;
'Sulfamic acid, ammonium hydrogen sulfate, 'methylammonium hydrogen acetate, ethyl ammonium hydrogen sulfate,
Examples include acids such as ae hydrogen hydroxyethylammonium.

In the present invention, it is necessary that the pH of the mixture of the initial condensate and the acid catalyst be 3.0 or less, preferably 2.0 or less. If the pH exceeds 3.0, the condensation reaction will not proceed sufficiently, and the average primary particle size of the resulting product will be 0.50μ.
1, the object of the present invention cannot be achieved.

The general amount of acid to adjust the pH to 3.0 or less is 1 to 30% by weight, especially 3.0% by weight based on the solid weight of the initial condensate.
A range of ˜20% by weight is used.

The acid catalyst is usually used in an aqueous solution and usually contains 1 to 10% by weight.
used in a concentration range of Further, the solid content concentration range of the initial condensate at this time is 10 to 40% by weight, and the temperature of the aqueous solution of the initial condensate is controlled within the range of 5 to 95°C.

When the initial condensate is reacted and solidified with an acid catalyst, more preferable results can be obtained by adding a water-soluble organic polymeric substance having a protective colloid effect to the initial condensate in advance. A water-soluble organic substance with a favorable protective colloid effect in this case (
Examples of the protective colloid agent (hereinafter referred to as protective colloid agent) include # powder and methyl cellulose.

Examples include natural products such as ethylcellulose and beta-hydroxyethylcellulose, and skin polymers such as polyvinyl alcohol and polyvinylpyrrolidone. How much protective colloid should be used?

Generally, 0.1 to 8% by weight and (0.2 to 5% by weight) based on the weight of the reaction products of all amine compounds and all aldehyde compounds.
Weight percentage ranges are often used. The protective colloid agent can be added at any stage before, during or after the formation of the initial condensate.

An acid catalyst is added and mixed with the initial condensate aqueous solution for the purpose of reacting and solidifying the initial condensate aqueous solution while stirring. In this case, preferably, the temperature of the initial condensate aqueous solution and the acid catalyst is adjusted to 20°C so that the initial condensate aqueous solution and the acid catalyst solidify within 50 seconds after addition and mixing. Adjust to a range of ~90°C. Industrially, the aqueous solution of the initial condensate and the acid catalyst are mixed using an in-line mixer or the like, and just before the assimilation of the mixture proceeds, the mixture is fed onto an extruder or a rotating endless belt to proceed with reaction solidification.

The thus obtained coagulate is dispersed into a slurry under stirring according to a conventional method, washed with water to reduce residual formaldehyde, neutralized, and crushed in a pulverizer to an average secondary particle size of 1 to 30μ, preferably 2 to 10μ. Upon grinding, a paper filler consisting of crosslinked aminoaldehyde polymer particles is obtained.

However, water washing to reduce residual formaldehyde is performed by repeating dispersion of the solidified material in water and filtration or centrifugation, but this operation removes residual formaldehyde, that is, unreacted formaldehyde, and water-soluble aminoaldehyde reactants. is removed. Therefore, removing residual formaldehyde by washing with water is not preferred from the viewpoint of improving the yield of the desired crosslinked aminoaldehyde polymer particles, and furthermore, it is necessary to treat the wastewater from several households, which requires a large amount of cost.

Therefore, as a method for reducing residual formaldehyde, after adding urea, ammonia or ammonium salt, sulfite or sulfite and reacting with residual formaldehyde, 1. Usually 90 to 95% moisture is added, but still a relatively small amount of water bathing is necessary. Contains unreacted substances such as natural urea, amine compounds, formaldehyde, and other aldehyde compounds, or reactants of these with ammonia, ammonium salts, sulfites, or sulfites, so solidified aminoaldehyde polymer particles are formed. A preferred method is to return the reaction system to its original state.

When adding urea as the method for reducing residual formaldehyde described above, urea can be added in solid form or as an aqueous solution, and the pH of the dispersion at this time
is usually 4.0 or less. The amount of urea added is equal to or more than the mole of residual formaldehyde present in the aqueous phase of the dispersion, the degree of urea is 10 to 70 °C, and the reaction time is 5 to 30 °C.
A range of minutes is sufficient.

In addition, when the above-mentioned reduction of residual formaldehyde is carried out using ammonia or ammonium salt, ammonia or ammonium salt is added in an amount of 0.5 to 4.0 mol per 1 mol of residual formaldehyde, and the reaction is carried out at 10 to 90°C. A time range of 5 to 100 minutes is sufficient.

When reducing residual formaldehyde using sulfite or sulfite, adding 0.5 to 1.5 moles of sulfite or its salt to 1 mole of residual formaldehyde and reacting at 10 to 90°C for several minutes is sufficient. It is.

As mentioned above, urea, ammonia or ammonium salts,
After reducing residual formaldehyde with sulfite or sulfite, the pH of the liquid is reduced with aqueous caustic soda or sulfuric acid solution.
H 5-10. Preferably, the particle size is adjusted to a range of 6 to 9, and the mixture is further stirred at 10 to 90°C for 5 to 100 minutes, and then ground to an average secondary particle size of 1 to 30 μm using a pulverizer. Then, it is filtered to obtain a cake-like product of liquid F and crosslinked aminoaldehyde polymer particles.

The P solution is returned to the reaction system before solidified crosslinked aminoaldehyde polymer particles are produced. That is, it is used as concentration adjusting water when obtaining an initial condensate and/or as concentration adjusting water for acidic water dissolution.

The thus obtained cross-linked aminoaldehyde polymer particle filler cake is reduced to 4 to 10% by weight by adding water and stirring.
A dispersion of polymer particles is added to a pulp slurry for making printing paper, and paper is made using a twin wire or Fourdrinier paper machine while stirring to obtain a uniform pulp slurry.

In this case, printing paper is uncoated paper, and refers to paper and newspaper rolls printed by general printing companies. Paper printed by general printing companies includes regular printing paper A, B, C, D, gravure paper, printing paper, securities paper, check paper, dictionary paper, book paper, telephone directory paper, etc. It is a printing paper made according to the paper, and includes lightweight printing paper.

The raw material pulp used for newspaper rolls and printing paper includes kraft pulp (KP), sulfite pulp (SP), semichemical pulp (SCP), CGP, TMP, RGP, GP, etc. obtained from softwood (N) and hardwood (L). semi-mechanical pulp, mechanical pulp, and deinked wastepaper pulp (DIP), etc., which are bleached to different degrees depending on the whiteness of the filter paper type used in paper making, and are used in various formulations.

The crosslinked aminoaldehyde polymer particle filler is added to the pulp slurry after the pulp is blended or at any step between the final step and the fan pump. It is usually preferable to add it in a machine chest. Sizing agent aluminum sulfate or clay, Merck, kaolin,
Fillers such as calcium carbonate can also be added to the machine chest at the same time for use or combination.

Printed papers obtained by adding cross-linked aminoaldehyde polymer particles are particularly useful for lightweight newspaper rolls, telephone directory paper, and other lightweight printing papers, and are suitable for offset printing due to their good receptivity to printing inks. Useful as paper.

〔Example〕

Examples will be described below, but the present invention is not limited thereto. The conditions for producing crosslinked aminoaldehyde polymer particles, the measurement methods for physical quantities, and the testing of processing conditions were conducted in the following manner.

The number of seconds for solidification after mixing the aminoaldehyde initial condensate and the acidic aqueous solution was determined by mixing within 5 seconds and then measuring the number of seconds until solidification.

The yield and yield of crosslinked aminoaldehyde polymer particles are:
First, the weight of the white cake-like material obtained was measured, and the JIS
The nonvolatile content, that is, the concentration of polymer particles is measured according to K-6801, and the yield of polymer particles is calculated from the formula: cake weight x polymer particle concentration. The yield of polymer particles is (number of parts of polymer particles yielded/number of parts of raw materials used) x 100
It is calculated by

The number of raw materials used is the total of the protective colloid agent, all amine compounds, and all aldehyde compounds, but the molecular weight of all aldehyde compounds is based on the chemical structure assumed after addition reaction and dehydration reaction are performed on all amino compounds. It was adopted.

The average primary particle size was calculated from electron micrographs.

The basis weight was measured and calculated according to JIS (P-8111).

The tightness was calculated by measuring the thickness of the paper according to JIS (P-8118) and using the formula (basis weight/thickness) x 100O.

The whiteness was measured using a Hunter whiteness meter using a blue filter.

White paper opacity was measured according to JIS (P-8138).

The opacity after printing was determined according to the method described in the literature (Paper Technology Times, September 1972, pages 1 to 13).

Offset ink acceptability is measured using R1 tester (manufactured by Mei Seisakusho)
Using a Molton roll, water was applied to the test piece, and under conditions that no picking occurred, solid printing was performed with black ink for offset printing, and ink receptivity (ink density) was judged with the naked eye. Evaluation was made on a 5-point scale, with 5 points being the most excellent and 1 point being the least acceptable.

Also, 1 part 1% is all based on weight (however, whiteness.

(Excluding white paper opacity and %, which is the unit of opacity after printing)
.

Example 1 After dissolving 20.0 parts of water and 0.33 parts of sodium salt of carboxymethyl cellulose (trade name Celogen F-3H) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. in a flask, 37
% formaldehyde aqueous solution and n-butyraldehyde 0.79 part, and the pH was adjusted with a caustic soda aqueous solution.
Adjust to 7.5. Next, 11.38 parts of urea, 0.49 parts of dicyandiamide and 5.71 parts of water were added and the temperature was raised to 70°C with stirring to conduct a condensation reaction for 2.0 hours.
The concentration of parts of the raw materials used is 27.0%, the molar ratio of amine compound to aldehyde compound is 1:1.15, dicyandiamide in the amine compound is 3 mol%, n in the aldehyde compound
- An aminoaldehyde initial condensate containing 3 mol % of butyraldehyde was obtained. This initial condensate was cooled to 45°C, and the amount of sulfuric acid equivalent to 6.98% based on the number of parts of the raw materials used, that is, 95%
4.0% diluted 1.26 parts of sulfuric acid with 28.57 parts of water
Mix quickly and uniformly with the aqueous solution.

It solidifies after about 46 seconds, at which time the temperature of the mixture rises to 59°C. Hold the sickle at about 59°C for 1 hour. Next, this solidified material is coarsely divided into particle association sizes of 1 to 2 using a cutter granulator, and 100 parts of water is added to form a slurry.
Neutralize the pH to 7.5 with 0% aqueous caustic soda solution. The resulting slurry was finely ground in a grinder, dispersed in 1000 parts of water, and filtered and dehydrated to obtain 76.93 parts of a white cake-like material of crosslinked aminoaldehyde polymer particle filler.

The nonvolatile content of this cake is 21.5%, so the yield is 16.54 parts, and the total raw material used is 17.0 parts.
Since it is 9 parts, the yield is 96.8%. The average primary particle size was 0.25μ.

Examples 2 to 13 and Comparative Examples 1 to 4 In Example 1, urea, dicyandiamide,
By changing the amounts of formaldehyde aqueous solution and n-butyraldehyde, the mol% of dicyandiamide in all amino compounds and the mol% of n-butyraldehyde in all aldehyde compounds were the same as in Example 1 except that they were shown in Table 1. A white cake of cross-linked aminoaldehyde polymer particle filler was obtained. The solidification reaction time, yield, and average primary particle size were as shown in Table 1.

Examples 14 to 15 and Comparative Example 5 A white cake-like material of crosslinked aminoaldehyde polymer particle filler was prepared in the same manner as in Example 2 except that the solidification reaction pH was changed as shown in Table 1 by changing the amount of sulfuric acid. I got it. Table 1 shows the solidification time, yield, and average primary particle size. p
In Comparative Example 5 where H is 4.0, the solidification reaction rate is slow, so the solidification time is as long as 180 seconds, and the average primary particle size is also 0.6
It was large at 9μ.

Examples 16 to 18 and Comparative Examples 6 to 7 In Example 2, the urea used, dianediamide,
A white cake-like material of crosslinked aminoaldehyde polymer particle filler was obtained in the same manner as in Example 2, except that the molar ratio of all amine compounds and all aldehyde compounds was changed by changing the amounts of formaldehyde aqueous solution and n-butyraldehyde. . The solidification reaction time, yield, and average primary particle size were as shown in Table 1. Comparative Example 6 with a molar ratio of i:o, s had a large average primary particle size of 0.7 μm, and Comparative Example 7 with a molar ratio of 1:2.3 had a low yield.

Application example 1 Beating degree (Hereinafter, the beating degree is C1 anadian S tan
dard.

Indicated by Freeness. )300-N, BKP25
%, RGP with a freeness of 190-, TMP with a freeness of 180-
20.0 parts of an absolute dry amount of DIP 25% with a freeness of 170 and 2000 parts of water were put into a disintegrator and dispersed for 2 minutes, and then the filler cake of Example 1 was mixed. Add water to 1 part of the dry weight to make 20 parts, make a dispersion with a concentration of 5% of the raw material used, and add this to a disintegrator and stir for 1 minute. The blended pulp slurry containing the filler of Example 1 was used to make paper using a square sheet machine.

Surface temperature after pressing for 15 minutes at 3 ks/cd 11
After drying by passing through a drum dryer at 5 ± 5 °C for 3 minutes, it was passed through a 7 kg/3 calender twice.

Sheathing was carried out for 24 hours in a constant temperature and humidity room with a humidity of 65% and a room temperature of 21° C. to obtain printing paper containing the filler of Example 1 and having a basis weight of 43.1 f/rd. Similarly, Examples 1 to 1
8. Printing papers containing the fillers of Comparative Examples 1 to 7 were obtained. These printed papers were measured for tightness, smoothness, whiteness, white paper opacity, post-print opacity, and acceptability of offset ink. These results are shown in Table-2.

As is clear from Table 2, the amount of dicyandiamide in all amine compounds and the amount of n-butyraldehyde in all aldehyde compounds of processed paper using the fillers of Examples 1 to 13, which are within the range of the present invention, are All of the properties are excellent, especially those using the fillers of Examples 2, 5 to 7, and 10 to 12. On the other hand, those using the filler of Comparative Example 1, which is outside the scope of the present invention, were particularly poor in opacity after printing and ink receptivity, and Comparative Examples 2 to 3
Those using fillers are particularly poor in whiteness.

Regarding the solidification reaction pH, the performance was excellent in all cases using the fillers of Examples 14 and 15, which are within the scope of the present invention, but in the case of using the filler of Comparative Example 5, which carried out the solidification reaction at pH 4. In particular, the degree of opacity after printing is poor.

The molar ratio of all amino compounds to all aldehyde compounds is within the scope of the present invention.Those using the fillers of Examples 16 to 18 had excellent performance, but 5 Comparative Example 6 was outside the scope of the present invention The paper containing the filler of Comparative Example 7 had poor opacity after printing, and the paper containing the filler of Comparative Example 7 was not so inferior in paper performance, but Table 1-7
As can be seen, the yield of filler is extremely low.

Example 19 20.0 parts by weight of water, celogen F-3HO1 in a flask
After adding and dissolving 33 parts, 17.33 parts of a 37% formaldehyde aqueous solution and alkylaldehyde were added.
0.81 part of butyraldehyde was added, and the pH was adjusted to 7.5 with an aqueous caustic soda solution. Next, 4.26 parts of urea, 5.97 parts of melamine, and 3.92 parts of water were added, and the temperature was raised to 70°C with stirring to conduct a condensation reaction for 2.0 hours, resulting in a concentration of parts of the raw materials used of 27.0%. .

The molar ratio of amine compound to aldehyde compound is 1 = 1.9
．． An aminoaldehyde initial condensate containing 40 mol% of melamine in the amino compound and 5 mol% of n-butyraldehyde in the aldehyde compound was obtained. This initial condensate was cooled to 45°C and immediately mixed with a 4.1% aqueous solution prepared by diluting 1.03 parts of 95% sulfuric acid with 23.40 parts of water, the number of parts of sulfuric acid corresponding to 6.89% based on the number of parts of the raw materials used. Mix evenly. Approximately 15
After a few seconds, the mixture solidifies and the temperature of the mixture rises to 60°C. Hold the sickle at about 60°C for 1 hour. Next, this solidified material is coarsely divided into particle association sizes of 1 to 2 m using a cutter granulator, 100 parts of water is added to form a slurry, and the slurry is neutralized to pH 7.5 with a 20% aqueous solution of caustic soda. The resulting slurry was pulverized in a pulverizer, dispersed in 1,000 parts of water, and filtered and dehydrated to obtain a white cake-like product. This was further dispersed in 1000 parts of water for washing with water, followed by filtration and dehydration to obtain 63.54 parts of a white cake-like material of crosslinked aminoaldehyde polymer particle filler. The nonvolatile content of this cake is 21.2%, so the yield is 13.47 parts, and since the total raw material used is 14.18 parts, the yield is 95.
It becomes 00%. Moreover, the average primary particle size was 0.17μ.

Example 20 According to the procedure of Example 19, using isobutyraldehyde instead of n-butyraldehyde in Example 19,
Also, by using guanidine instead of melamine, the molar ratio of amine compound to aldehyde compound is 1:1.5. Except that guanidine in the amine compound was changed to 10 mol% and isobutyraldehyde in the aldehyde compound was changed to 10 mol%.
The conditions for obtaining the initial condensate, such as the concentration of the raw materials used and the combination conditions, were exactly the same, and the solidification conditions, conditions and operations until the cake was obtained were the same as in Example 16, except that the solidification time was 37 seconds. In exactly the same manner, 60.69 parts of a white cake-like material of cross-linked aminoaldehyde polymer particle filler was obtained. The nonvolatile content of this cake is 20.8%, so the yield is 12.62 parts and 1 total raw material used is 13.40 parts.
The yield is 94.2%. The average primary particle size was 0.23μ.

Example 21 Summary of Example 19 Therefore, in Example 19, 10 mol% of thiourea was used instead of melamine as the amino compound, and 10 mol% of n-butyraldehyde was used as the aldehyde compound, and the molar ratio of the amine compound to the aldehyde compound was Except that the ratio was 1:1.7, the conditions for obtaining the initial wire mesh such as the concentration of the raw materials used and the condensation conditions were exactly the same, and the solidification conditions and cake were obtained except that the solidification time was 19 seconds. Example 21 was performed using exactly the same operations and conditions up to
84.79 parts of a white cake of cross-linked aminoaldehyde polymer particle filler was obtained. The nonvolatile content of this cake is 20.4%, so the yield is 17.30 parts, and since the total raw material used is 18.42 parts, the yield is 93.
It becomes 9%. The average primary particle size was 0.35μ.

Example 22 In Example 19, according to the procedure of Example 19, 7 mol% of acetoguanidine was used instead of melamine as the amino compound, 7 mol% of isobutyraldehyde was used as the aldehyde compound, and the molar ratio of the amino compound to the aldehyde compound was 1: 1.6, the conditions for obtaining the initial wire mesh, such as the concentration of the raw materials used and the condensation conditions, were completely the same, and the solidification conditions and operations until the cake was obtained, except that the solidification time was 14 seconds. Example 22 was carried out under the same conditions.
87.24 parts of a white cake of crosslinked aminoaldehyde polymer particle filler was obtained. The non-volatile content of this cake is 20.8%, so the yield is 18.15 parts, and since the total raw material used is 19.04 parts, the yield is 95.
It will be 3%. The average primary particle size was 0.21μ.

The above Examples 19 to 22 are summarized in Table 3.

Table 3 Application Example 2 Printing papers containing the fillers of Examples 19 to 22 were obtained in the same manner as Application Example 1. The performance of these printing papers was excellent as shown in Table 4.

Table 4 [Effects of the Invention] As is clear from the above, the printing paper containing the filler produced according to the present invention has a high degree of whiteness and white paper opacity.

Excellent opacity and ink receptivity after printing, and 1 tsubo weight is 4.
Even at 3 f/d, paper containing this filler has sufficient performance as printing paper.

Therefore, the present invention is of great significance also from the point of view of reducing the weight of paper.

Claims (1)

[Claims] Consisting of 1.0 mol part of urea and 1.0 to 2.0 mol parts of formaldehyde, 50 mol% or less of the urea is substituted with cyanamide or a dicyanamide derivative, and 50 mol% or less of the formaldehyde is substituted with alkyl aldehyde. or substituted with an alkenyl aldehyde,
Alternatively, an aminoaldehyde initial condensate in which either the urea or the formaldehyde is substituted with the above-mentioned one, and an acid catalyst are mixed and solidified at a pH of 3.0 or less, and the average primary particle size is A method for producing a paper filler having a particle size of 0.15 to 0.50μ.