JP3397816B2 - Dispersant for inorganic filler - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to dispersants, and more particularly to dispersants used for inorganic fillers.

[0002]

2. Description of the Related Art Inorganic pigments such as calcium carbonate, titanium oxide, iron oxide, zinc oxide, aluminum hydroxide, barium sulfate, gypsum, silica, clay, satin white, talc and carbon black are used for paper coating, water-based paint and It is widely used as a filler in gypsum board and the like, and a dispersant is used for improving product quality, manufacturing process and workability.

As such a dispersant, a polycarboxylic acid containing acrylic acid or maleic acid as a main constituent unit, or a formaldehyde condensate such as naphthalenesulfonic acid or alkylnaphthalenesulfonic acid has been conventionally used. In addition to phenolsulfonic acid, a dispersant composed of a formaldehyde condensate obtained by reacting phenol and formaldehyde has also been proposed (JP-A-4-110031).

However, the above-mentioned dispersants aim to improve product quality such as improvement of physical properties of coating film, improve manufacturing process such as shortening of stirring, transportation and drying time, or reduction of costs required for transportation and storage. However, there is a drawback that it is difficult to sufficiently meet the demand for further increasing the concentration of the dispersoid in order to improve workability. On the other hand, the present inventors have already proposed a formaldehyde condensate of a bisphenol and a phosphite or an aminocarboxylic acid as a water reducing agent for cement or as a dispersant for dyes (JP-A-3-290).
No. 343, No. 3-255119, and Japanese Patent Application No. 3-1304.
No. 46, No. 3-152515), with good results. Therefore, the present inventors have found that good results are obtained when the above-mentioned formaldehyde condensate having a specific weight average molecular weight or more is used as a dispersant for an inorganic filler, and the present invention has been achieved. did.

[0005]

Therefore, an object of the present invention is to provide a dispersant for an inorganic filler which has an unprecedentedly excellent dispersibility and therefore can increase the concentration of dispersoid. is there.

[0006]

The above objects of the present invention are as follows.
Sulfite and / or 1.0 mol of bisphenols
Alternatively, it contains a condensate having a weight average molecular weight of 10,000 or more, which is obtained by reacting 0.8 to 1.5 mol of aminocarboxylic acid and 2.0 to 3.5 mol of formaldehyde under alkaline aqueous conditions. Achieved by the featured inorganic filler dispersant.

Examples of the bisphenols used in the present invention include 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,
4 '-(perfluoroisopropylidene) diphenol, 4,4'-dihydroxydiphenylmethane, 2,2
-Bis (4-hydroxyphenyl) propane, 2,2-
Examples thereof include bis (4-hydroxyphenyl) butane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxybiphenyl and isomers thereof. You may use these together. Among these bisphenols,
Particularly, 2,2-bis (4-hydroxyphenyl) propane, 4,4′-dihydroxydiphenyl sulfone, 4,
4'-dihydroxydiphenylmethane, and 4,4'-
Dihydroxydiphenyl sulfone and 2,2-bis (4-
Preference is given to using a mixture with hydroxyphenyl) propane.

Examples of the sulfite used in the present invention include sodium sulfite, potassium sulfite, calcium sulfite and ammonium sulfite. The sulfite in the present invention also includes bisulfite such as sodium bisulfite (sodium hydrogen sulfite). The aminocarboxylic acid used in the present invention means a low molecular weight amino acid and a salt thereof, and specifically, glutamic acid, iminodiacetic acid, aspartic acid, aminobutyric acid, glycine, alanine and the like and salts thereof. . Of these, two carbons in the molecule , especially glutamic acid.
It is preferable to use an aminocarboxylic acid having a xyl group or a salt thereof.

The formaldehyde used in the present invention is usually formaldehyde in an aqueous solution, but includes formaldehyde derivatives such as paraformaldehyde. The condensate used in the present invention is the above-mentioned bisphenol,
It can be easily obtained by reacting sulfite and / or aminocarboxylic acid and formaldehyde under alkaline aqueous conditions, but a condensate reacted under the following conditions is particularly preferable.

The reaction rate is such that bisphenols are
Mol, B mol of sulfite and / or aminocarboxylic acid,
When formaldehyde is C mol, especially A: B: C
= 1: 0.8 to 1.5: in the range of 2.0 to 3.5.
The reaction is carried out under alkaline aqueous conditions. In this case, the aqueous solution before the reaction is in a solid-liquid or suspended state, and the accurate p
Since it is difficult to measure H, it is preferable to add alkali as follows. That is, when a sulfite is used, the amount of the alkali added is in the range of 0 to 1.5 molar equivalent, preferably 0 to 1.
It is in the range of 0 molar equivalents, and when bisulfite is used, it is in the range of 0 to 2.0 molar equivalents, preferably 1.0 to 1.5 molar equivalents, relative to 1.0 mol of bisulfite. When the aminocarboxylic acid is used, it is in the range of 0 to 3.0 molar equivalent, preferably 0 to 2.5 molar equivalent, relative to 1 mol of the aminocarboxylic acid.

Examples of preferable alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide and the like. When a salt of aminocarboxylic acid is used, it is preferable to add the above-mentioned number of moles of alkali minus the number of moles of aminocarboxylic acid salt used. In the condensation reaction, the concentration of the reaction product is usually 20 to 40% by weight, and the reaction temperature is 80 to 100.
The reaction is carried out under conditions of a temperature of 2 ° C. and a reaction time of 2 to 40 hours. The condensate when the reaction is carried out outside the range of the above conditions,
It contains a large amount of a low molecular weight condensate that does not exhibit dispersibility with respect to the inorganic filler, or becomes too high in molecular weight to have a strong cohesive property, making it unsuitable as a dispersant for an inorganic filler. The weight average molecular weight of the obtained condensate can be easily measured by a polyethylene glycol conversion method by gel permeation chromatography (GPC).

The weight average molecular weight of the condensate obtained as described above is usually in the range of 1,000 to 30,000, but in the present invention, a condensate of 10,000 or more is particularly used. The reason why the dispersant of the present invention has excellent dispersibility as an inorganic filler is not clear, but the condensate used has a small number of low molecular weight parts as compared with a phenol-based condensate, and an inorganic material having high polarity. It is presumed that it has a structure in which an electric repulsive force is easily exerted on the pigment and the like.

[0013]

When the dispersant of the present invention is used as an inorganic filler, the dispersoid concentration can be increased because the dispersibility is better than ever.

[0014]

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto.
In addition, "part" which shows a compounding quantity shows a weight part. A synthesis example of the condensate according to the present invention is shown below.

Synthesis Example 1. In a reaction vessel equipped with a stirrer, a reflux device and a formaldehyde aqueous solution dropping device, 2, 2
-Bis (4-hydroxyphenyl) propane 228.3
Parts (1 mol), 126.1 parts of sodium sulfite (1 mol) and 830 parts of water were charged. The resulting mixed solution is mixed with 10
Heated to 0 ° C, 37% by weight aqueous formaldehyde solution 1
1 part of 94.6 parts (2.4 mol of formaldehyde)
After dropping over a period of time, reaction was performed at 100 ° C. for 25 hours to obtain an aqueous solution of a condensate. GPC of the obtained condensate
The weight average molecular weight of the polyethylene glycol standard conversion measured by using was 10.500.

Synthesis Example 2. 4,4 'in a reaction vessel equipped with stirrer, reflux device and formaldehyde solution dropping device
250.3 parts (1 mol) of dihydroxydiphenyl sulfone, 126.1 parts (1 mol) of sodium sulfite, 42.6 parts of a 47% by weight aqueous solution of sodium hydroxide (0.5 mol as sodium hydroxide) and 860 parts of water. Was charged. The obtained mixed liquid was heated to 100 ° C., and 243.3 parts of a 37% by weight aqueous formaldehyde solution (3 mol as formaldehyde) was added dropwise over 1 hour, followed by reacting at 100 ° C. for 35 hours to obtain an aqueous solution of a condensate. Obtained. The resulting condensate had a weight average molecular weight of 9,400 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 3. 4,4 'in a reaction vessel equipped with stirrer, reflux device and formaldehyde solution dropping device
75.1 parts of dihydroxydiphenyl sulfone (0.3
Mol), 2,2-bis (4-hydroxyphenyl) propane 182.6 parts (0.8 mol), sodium bisulfite 109.2 parts (1.05 mol), sodium hydroxide 4
8.0 parts (1.2 mol) and 845 parts of water were charged. The obtained mixed liquid was heated to 100 ° C., 227.0 parts of 37% by weight aqueous formaldehyde solution (2.8 mol as formaldehyde) was added dropwise over 1 hour, and then the mixture was heated at 100 ° C.
The reaction was carried out for 5 hours to obtain an aqueous solution of the condensate. The obtained condensate had a weight average molecular weight of 9,200 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 4. In a reaction vessel equipped with a stirrer, a reflux device and a formaldehyde aqueous solution dropping device, 2, 2
-Bis (4-hydroxyphenyl) propane 228.3
Parts (1 mol), sodium glutamate 187.2 parts (1 mol), sodium hydroxide 40.0 parts (1 mol) and water 840 parts were charged. The obtained mixed liquid was heated to 80 ° C., 202.7 parts of a 37% by weight aqueous formaldehyde solution (2.5 mol as formaldehyde) was added dropwise over 1 hour, and then the mixture was reacted at 85 ° C. for 10 hours to give a condensate. An aqueous solution was obtained. The obtained condensate had a weight average molecular weight of 11,500 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 5. In a reaction vessel equipped with a stirrer, a reflux device and a formaldehyde solution dropping device,
24 'parts of 4'-dihydroxy diphenyl sulfone (0.96 mol), sodium glutamate 187.2
Parts (1 mol), 56.0 parts of sodium hydroxide (1.4 mol) and 860 parts of water were charged. The resulting mixed solution is mixed with 10
Heated to 0 ° C., 37% by weight formaldehyde aqueous solution 20
2.7 parts (2.5 mol of formaldehyde) was added dropwise over 1 hour, and then reacted at 100 ° C. for 25 hours,
An aqueous solution of the condensate was obtained. The obtained condensate had a weight average molecular weight of 9,600 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 6. In a reaction vessel equipped with a stirrer, a reflux device and a formaldehyde aqueous solution dropping device, 2, 2
-Bis (4-hydroxyphenyl) propane 228.3
Parts (1 mol), 75.7 parts (0.6 mol) of sodium sulfite and 830 parts of water were charged. The resulting mixed solution is mixed with 10
Heated to 0 ° C, 37% by weight formaldehyde aqueous solution 4
8.6 parts (0.6 mol of formaldehyde) was added dropwise over 1 hour. After reacting at 100 ° C. for 2 hours, 74.9 parts (0.4 mol) of sodium glutamate was added, and then a 37% by weight formaldehyde aqueous solution 162.
After 2 parts (2.0 mol of formaldehyde) was added dropwise over 1 hour, the mixture was further reacted at 100 ° C. for 15 hours,
An aqueous solution of the condensate was obtained. The resulting condensate had a weight average molecular weight of 6,500 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 7. 37% by weight used in Synthesis Example 1
Other than changing the formaldehyde aqueous solution 194.6 parts to 267.6 parts (3.3 mol of formaldehyde),
An aqueous solution of the condensate was obtained in exactly the same manner as in Synthesis Example 1. The obtained condensate had a weight average molecular weight of 13,000 in terms of polyethylene glycol standard measured by GPC.

Synthesis Example 8. 37% by weight used in Synthesis Example 1
An aqueous condensate solution was obtained in exactly the same manner as in Synthesis Example 1, except that the amount of the aqueous formaldehyde solution was changed to 137.8 parts (1.7 mol of formaldehyde). The resulting condensate,
The polyethylene glycol standard conversion weight average molecular weight measured by GPC was 3,500.

Synthesis Example 9. An aqueous solution of a condensate was obtained in the same manner as in Synthesis Example 2 except that the 47 wt% sodium hydroxide aqueous solution used in Synthesis Example 2 was not used. The resulting condensate had a weight average molecular weight of 2,400 in terms of polyethylene glycol standard measured by GPC.

Dispersant for Comparative Example For comparison, a polycarboxylic acid-based pigment dispersant (Aron T-40: trade name of Toa Gosei Chemical Industry Co., Ltd .; hereinafter abbreviated as PC), naphthalene sulfonic acid. formaldehyde condensates based pigment dispersing agent (Bani O Lumpur HD-200: Sanyo trade name manufactured Kokusaku pulp Co., hereinafter abbreviated as NSF)
And a formaldehyde condensate of phenolsulfonic acid and phenol (hereinafter abbreviated as PPH). Incidentally, PP
H was synthesized as follows according to the method disclosed in JP-A-4-110031.

Synthesis of PPH In a reaction vessel, sodium phenolsulfonate 196.
0 parts (1 mol), 6.6 parts of phenol (0.07 mol), 89.2 parts of 37% by weight aqueous formaldehyde solution (1.1 mol as formaldehyde) and 325 parts of water were charged, and 10% by weight of sodium hydroxide was added. Adjust the pH of the reaction solution to 8.5 using an aqueous solution,
The mixture was stirred at reflux at 20 ° C for 20 hours. After cooling the obtained reaction mixture to 30 ° C., a 10% by weight aqueous solution of sodium hydroxide was added dropwise to adjust the pH to 10.5, and then 10
The mixture was heated to 0 ° C., refluxed for 3 hours, and stirred to obtain an aqueous solution of condensate. The condensates according to the present invention and PPH, PC and NSF synthesized as described above were tested for dispersion performance as follows.

Dispersion Performance Test 1 Examples 1 to 10 and Comparative Examples 1 to 1 1 . 250 parts of precipitated calcium carbonate for papermaking having an average particle diameter of 0.14 μm (PZ: trade name of Shiraishi Industry Co., Ltd.), and 200 parts of water with the dispersant, PC and NSF prepared in Synthesis Examples 1 and 4, respectively. A liquid obtained by adding 0.25% by weight, 0.50% by weight, 0.75% by weight, 1.00% by weight, 1.50% by weight, and 2.00% by weight in terms of solid content to the calcium carbonate. And 8,000 using a homomixer
0 rev / min in stirred and mixed for 20 minutes to obtain a 2 single slurry in total. About 2 single slurry obtained, each viscosity after lapse of 2 minutes from the start of rotation of the rotor was measured using a B-type rotary viscometer. The result is as shown in FIG.

The dispersibility Test 2 Example 1 1, 1 2 and Comparative Example 1 2-1 4. Mean papermaking precipitated calcium carbonate having a particle diameter of 0.46 .mu.m (PC: Shiraishi trade name Industry Co., Ltd.) 150 parts, and dispersing agents and PC were prepared in 100 parts of water in Synthesis Example 1, 4及beauty 9, the NSF A mixture of 1.0% by weight in terms of solid content with respect to each of the above-mentioned calcium carbonate was stirred and mixed with a homomixer at 8,000 rpm for 20 minutes,
A slurry of each dispersant was obtained. Table 1 shows the results of measuring the viscosities of the obtained slurries using a B-type rotational viscometer immediately after preparation and after 6 days. The measured value is a value after 2 minutes have elapsed from the start of rotation of the rotor.

[0028]

[Table 1]

The dispersion performance test 3 Example 1 3-2 0 and Comparative Example 1 5-2 6. Hemihydrate gypsum (SK: product name of Mutsu Chemical Industry Co., Ltd.) 3
To 192 parts of water, the dispersant prepared in Synthesis Example 1 and Synthesis Example 4 and PC, NSF, and PPH were added in an amount of 0.2% by weight and 0.5% by weight in terms of solid content based on the hemihydrate gypsum. ,
Each liquid added with 1.0% by weight and 1.5% by weight was added over 1 minute, and stirred for 1 minute (100 times) with a rod having a diameter of 15 mm to obtain each slurry. The viscosity of each of the obtained slurries was immediately measured using a B type rotational viscometer. The result is as shown in FIG.

Dispersion Performance Test 4 Examples 2 1 to 2 7 and Comparative Examples 2 7 to 2 8 . Hemihydrate gypsum (SK: product name of Mutsu Chemical Industry Co., Ltd.) 3
00 parts was added to 205 parts of water in a liquid prepared by adding 3 parts of the 9 kinds of dispersants prepared in Synthesis Examples 1 to 9 in terms of solid content over 1 minute, and the mixture was further added for 1 minute using a rod having a diameter of 15 mm. Stir (1
(00 times) to obtain each slurry. The viscosity of each of the obtained slurries was immediately measured using a B type rotational viscometer. The results are shown in Table 2.

[0031]

[Table 2]

The dispersion performance test 5 Example 28-3 1 and Comparative Example 2 9 and 30. In 160 parts of titanium oxide (TI-PURE R-960: trade name of DuPont Japan Co., Ltd.) and 140 parts of water, 0.64 parts of the dispersant prepared in Synthesis Examples 1 to 4 and Synthesis Example 8 in terms of solid content. The added liquid was stirred and mixed with a homomixer at 6,000 rpm for 5 minutes to obtain a slurry of each dispersant. The viscosity of each slurry immediately after being obtained was measured using a B-type rotational viscometer. The results are as shown in Table 3.

[0033]

[Table 3]

The above results demonstrate that the dispersant of the present invention has excellent dispersion performance.

[Brief description of drawings]

FIG. 1 is a dispersant and PC prepared in Synthesis Examples 1 and 4,
The slurry obtained by adding the NSF to calcium carbonate (Examples 1 to 1 0, and Comparative Example 1 to 1 1) is a diagram showing a change in viscosity relative to the addition amount of the dispersing agent.

FIG. 2 is a dispersant and PC prepared in Synthesis Examples 1 and 4,
NSF, the PPH hemihydrate gypsum against added to the resulting slurry (Example 1 3-2 0 and Comparative Example 1 5-2 6) is a diagram showing a change in viscosity relative to the addition amount of the dispersing agent.

Front page continuation (72) Inventor Taro Abe 2-8-1, Iida-cho, Iwakuni-shi, Yamaguchi Sanyo-Kokusaku Pulp Co., Ltd., Production Technology Laboratory (56) Reference JP-A-56-50915 (JP, A) Kai 53-145353 (JP, A) JP 3-255119 (JP, A) JP 4-352751 (JP, A) JP 52-108493 (JP, A) (58) Fields investigated (58) Int.Cl. ⁷ , DB name) B01F 17/52 C04B 24/22 C04B 24/30 D21H 17/49 C08G 8/20

Claims (4)

(57) [Claims] 1. A bisphenol compound ( 1.0 mol ) is reacted with sulfite and / or aminocarboxylic acid (0.8 to 1.5 mol ) and formaldehyde ( 2.0 to 3.5 mol ) under alkaline aqueous conditions. The obtained weight average molecular weight is 1.
A dispersant for inorganic fillers, which contains at least 10,000 condensates. 2. Bisphenols are 2,2-bis (4-
The dispersant for inorganic filler according to claim 1, which is hydroxyphenyl) propane and / or 4,4′-dihydroxydiphenylsulfone. 3. The dispersant for an inorganic filler according to claim 1, wherein the aminocarboxylic acid is an aminocarboxylic acid having two carboxyl groups in the molecule. 4. The dispersant for an inorganic filler according to claim 3, wherein the aminocarboxylic acid is glutamic acid.