JPH08217507A - Dispersant for aqueous gypsum slurry - Google Patents

Abstract

PURPOSE: To improve the dispersibility and foam stability of an aq. gypsum slurry by using the condensate (neutral salt) of the aromatic compd. having an introduced oxyalkylene group and the aromatic compd. having a carboxyl with formaldehyde as the essential component. CONSTITUTION: 1-98mol% aromatic compd. having an introduced 2-3C oxyalkylene group, 1-98mol% aromatic compd. contg. a carboxyl and 1-98mol% aromatic compd. having a sulfonic group, if necessary, are charged into a reaction vessel and agitated at 70-90 deg.C, aq. formalin is dripped in 1 to 4hr, and the mixture is condensed under reflux and neutralized, as required, to obtain the dispersant for an aq. gypsum slurry consisting of the formaldehyde condensate (neutral salt) having 3,000-100,000 weight average mol.wt. (the condensation degree calculated from the mol.wt. by the gel permeation chromatography/ polystyrene sodium sulfonate conversion method).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dispersant for gypsum / water slurry. More specifically, gypsum during gypsum board manufacturing
The present invention relates to a dispersant having excellent dispersibility of water slurry and foam stability.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a dispersant for gypsum / water slurry, naphthalene sulfonic acid formaldehyde condensate (hereinafter referred to as naphthalene type)
It has been known. In the production of gypsum board, the amount of kneading water is reduced by using the naphthalene-based dispersant, the drying time can be shortened, and the productivity is improved.

In the production of gypsum board, gypsum, an admixture aqueous solution, a hardening accelerator aqueous solution, etc. and foam are simultaneously and continuously charged into a kneading machine called a pin mixer in accordance with a predetermined composition.
It consists of a production process in which it is discharged with stirring for about a second and sandwiched between the upper and lower boards (paper).

However, even if a predetermined amount of foam is added, its foam breaking property is large. Therefore, it is the current situation that about twice the amount of foam is usually added in anticipation of the volume to be broken.

Further, coarse bubbles generated in the process of breaking the bubbles aggregate at the interface with the board to hinder the adhesion with the gypsum slurry, which causes poor quality.

[0006]

DISCLOSURE OF THE INVENTION In view of the above problems, the present inventors have made earnest studies, and as a result, have found that the dispersant has a great influence on the breakage of foam, and by using the dispersant of the present invention, It came to a solution.

That is, the conventional naphthalene-based dispersant has a large defoaming action against the foam of the surfactant, causes a volume decrease due to foam breaking, and requires a large amount of foam. In addition, the coarse bubbles generated in the defoaming process are the cause, which causes the inhibition of the adhesion between the gypsum slurry and the board.

[0008] Therefore, the present inventors have completed the present invention as a result of intensive studies aimed at a dispersant having a small defoaming action and a large dispersing action with respect to foam.

That is, the present invention relates to an aromatic compound having one or more kinds (A) selected from aromatic compounds having 1 to 300 moles of an oxyalkylene group having 2 to 3 carbon atoms and a carboxyl group. One or more selected from
The present invention relates to a gypsum / water slurry dispersant containing a formaldehyde cocondensate with (B) or a neutralized salt thereof as an essential component.

The present invention further relates to an aromatic compound having a carboxyl group and one or more kinds (A) selected from aromatic compounds having 1 to 300 mol of an oxyalkylene group having 2 to 3 carbon atoms. One or more selected from
Dispersing agent for gypsum / water slurry containing as an essential component a formaldehyde co-condensate with (B) and one or more selected from aromatic compounds having sulfonic acid groups (C) .

The co-condensate in the present invention has a structure having an alkylene oxide and a carboxyl group in an aromatic formaldehyde co-condensation system, and has an enhanced adsorptivity to gypsum.

Further, by introducing an alkylene oxide group into the aromatic formaldehyde co-condensation system as in the present invention, the steric hindrance repulsive force of the alkylene oxide group is added to the dispersibility due to the electric repulsive force inherent in the aromatic system, resulting in a dispersion effect. Is extremely high.

The aromatic compound (A) having 1 to 300 moles of oxyalkylene group having 2 to 3 carbon atoms used in the present invention is a polyoxy group having 1 to 300 moles of oxyalkylene group having 2 to 3 carbon atoms. Alkylenealkylphenols or polyoxyalkylenealkylnaphthols are used. One example is an addition product of 1 to 300 mol of oxyalkylene group to phenol, cresol, nonylphenol, naphthalene, methylnaphthalene, butylnaphthalene, bisphenol and the like.

From the viewpoint of co-condensation, a benzene ring derivative, that is, a polyoxyalkylene alkylphenol is preferable, and an oxyalkylene group adduct of phenol is particularly preferable.

The oxyalkylene group having 2 to 3 carbon atoms means ethylene oxide and propylene oxide, which may be random or block and is not limited. Further, the terminal of the oxyalkylene group may be a hydroxyl group, an alkyl ether or an alkyl ester.

The alkylene oxide adduct having 2 to 3 carbon atoms of phenol may have an average number of moles of addition of 1 or more, and may contain an unadded one or a non-added one. Can be used in any case. However, if the oxyalkylene group
If it exceeds 300 moles, the dispersibility is lowered, which is not preferable.

As the aromatic compound (B) having a carboxyl group used in the present invention, naphthalene ring or benzene ring derivatives such as isophthalic acid, oxynaphthoic acid, benzoic acid, hydroxybenzoic acid and the isomers thereof are used. It

However, considering the co-condensation property, the compound represented by the following general formula (a) is preferable.

[0019]

Embedded image

That is, o-hydroxybenzoic acid, m-hydroxybenzoic acid and p-hydroxybenzoic acid are preferred.

The aromatic compound (C) having a sulfonic acid group used in the present invention is an alkylnaphthalenesulfonic acid, an alkylphenolsulfonic acid, an anilinesulfonic acid, an alkylbenzenesulfonic acid, and the like. Examples thereof include naphthalenesulfonic acid and methylnaphthalene. Examples thereof include sulfonic acid, butylnaphthalene sulfonic acid, phenol sulfonic acid, cresol sulfonic acid, aniline sulfonic acid, benzene sulfonic acid and toluene sulfonic acid. It is also possible to use these isomers and those which have already been condensed. For example, lignin sulfonic acid or naphthalene sulfonic acid formaldehyde condensate can be used.

However, considering the co-condensation property, a sulfonic acid compound consisting of a phenol derivative, that is, an alkylphenol sulfonic acid is preferable, and a phenol sulfonic acid is particularly preferable.

Further, it may be reacted with another co-condensable monomer within a range that does not impair the effects of the present invention. Examples thereof include alkylphenols such as phenol and cresol.

The co-condensate can be used as a dispersant for gypsum / water slurry as it is, but it is preferably used as a neutralizing salt from the viewpoint of storage and use. Examples of the neutralizing salt include monovalent metal salts, divalent metal salts, ammonium salts, amine salts and substituted amine salts.

1 to 30 oxyalkylene groups having 2 to 3 carbon atoms
Formaldehyde co-condensate of 1 or 2 or more (A) selected from 0 mol of an aromatic compound and 1 or 2 or more (B) selected from an aromatic compound having a carboxyl group. Alternatively, in the neutralized salt thereof, the reaction molar ratio of (A) and (B) is preferably (A) / (B) = 1 to 99/99 to 1 for dispersibility, and 10 to 50/50 to A range of 90 is especially preferred.

1 to 30 oxyalkylene groups having 2 to 3 carbon atoms
It has one or more kinds (A) selected from aromatic compounds introduced with 0 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group and a sulfonic acid group. In the formaldehyde co-condensate with one or more kinds (C) selected from aromatic compounds or a neutralized salt thereof, the reaction molar ratio of (A), (B) and (C) is
(A) / (B) / (C) = 1 to 98/1 to 98/1 to 98 is preferable, and 5 to 50/5 to 90/5 to 90 is particularly preferable.

The standard method for producing the co-condensate of the present invention is shown below, but the present invention is not limited thereto.

As a method for producing the cocondensate, for example, a predetermined amount of alkylene oxide adduct and an aromatic compound having a carboxyl group, or an aromatic compound having a carboxyl group and an aromatic compound having a sulfonic acid group are used in a reaction vessel. And a predetermined amount of formalin water is added dropwise over 1 to 4 hours under stirring at 70 to 90 ° C., and after dropping, the mixture is stirred under reflux for 3 to 30 hours, cooled, and neutralized.

In the co-condensation system, water is added to control the condensation viscosity and the condensation time. The reaction system is carried out under acidic conditions, and when it is already under acidic conditions due to the aromatic compound having a sulfonic acid group and the unreacted acid contained therein, the condensation is carried out in the acidic region as it is. If the reaction system does not cause acidity, sulfuric acid or the like is added in advance to adjust the pH to 2 or less and the reaction is performed.

The weight average molecular weight of the cocondensate or a neutralized salt thereof in the present invention (calculated from the molecular weight by gel permeation chromatography / sodium polystyrene sulfonate conversion) is preferably 3,000 to 100,000,
5,000 to 50,000 is more preferable. If the average molecular weight is less than 3,000 or more than 100,000, the dispersibility is poor.

The amount of the dispersant of the present invention added to gypsum is preferably 0.01 to 1.0% by weight, and 0.05 to 1.0% by weight based on the solid content of gypsum.
0.2% by weight is more preferred.

[0032]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited to these examples.

The molecular weight in the examples represents the weight average molecular weight (gel permeation chromatography / sodium polystyrene sulfonate conversion).

An aromatic compound (A) having 1 to 300 mol of an oxyalkylene group having 2 to 3 carbon atoms used in the Examples,
The contents of the aromatic compound (B) having a carboxyl group and the aromatic compound (C) having a sulfonic acid group are shown below. still,
EO represents ethylene oxide, PO represents propylene oxide, and the numerical value represents the average number of added moles.

<Aromatic Compound (A)>A-1; Phenol EO 10 mol adduct A-2; Phenol EO 25 mol adduct A-3; Phenol EO 75 mol adduct A-4; Phenol EO 120 mol adduct Product A-5: Phenol EO 250 mol · PO 20 mol block adduct A-6: Naphthol EO 2 mol adduct A-7 (comparative); Phenol EO 370 mol adduct.

<Aromatic Compound (B)> B-1; p-hydroxybenzoic acid B-2; o-hydroxybenzoic acid B-3; oxynaphthoic acid.

<Aromatic Compound (C)>C-1; phenolsulfonic acid C-2; p-cresolsulfonic acid C-3; naphthalenesulfonic acid formaldehyde condensate (molecular weight 4500).

Production Example 1 (symbol D-1 of dispersant) 0.3 mol of A-1, 0.7 mol of B-1, 0.5 mol of sulfuric acid and 4 mol of water were charged in a reaction vessel with stirring, and 37 mol of formaldehyde 0.9 mol. Is added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ℃ and react for 10 hours, then cool to 50%.
Adjust to pH 8 with sodium hydroxide and let stand. After standing still,
The upper layer separated from the two layers was taken, and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 21,000.

Production Example 2 (symbol D-2 of dispersant) 0.2 mol of A-3, 0.7 mol of B-1, 0.1 mol of B-2, 0.5 mol of sulfuric acid and 5 mol of water were placed in a reaction vessel with stirring. After charging, 0.9 mol of 37% formaldehyde is added dropwise at 80 ° C. over 3 hours. After completion of the dropping, the temperature is raised to 105 ° C. and reacted for 12 hours, then cooled, adjusted to pH 8 with 50% sodium hydroxide and allowed to stand. After standing still, the upper layer separated into two layers was taken, and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 19,000.

Production Example 3 (Dispersant symbol D-3) 0.1 mol of A-4, 0.9 mol of B-1, 0.5 mol of sulfuric acid and 4 mol of water were charged into a reaction vessel with stirring, and 0.9 mol of 37% formaldehyde was added. Is added dropwise at 80 ° C. over 3 hours. After the dropping, raise the temperature to 105 ℃ and react for 10 hours, then cool to 50%.
Adjust to pH 8 with sodium hydroxide and let stand. After standing still,
The upper layer separated from the two layers was taken and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 42,000.

Production Example 4 (symbol D-4 of dispersant) 0.3 mol of A-1, 0.3 mol of B-1, 0.1 mol of C-1, 0.3 mol of sulfuric acid and 4 mol of water were placed in a reaction vessel with stirring. After charging, 0.9 mol of 37% formaldehyde is added dropwise at 80 ° C. over 3 hours. After the completion of the dropping, the temperature is raised to 105 ° C. and the reaction is performed for 10 hours. Then, the mixture is cooled, adjusted to pH 8 with 50% sodium hydroxide and left to stand. After standing still, the upper layer separated into two layers was taken and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 12,000.

Production Example 5 (symbol D-5 of dispersant) 0.3 mol of A-2, 0.6 mol of B-1, 0.1 mol of C-2 and 5 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the dropping is completed, the temperature is raised to 105 ° C and reacted for 12 hours.
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 17,000.

Production Example 6 (symbol D-6 of dispersant) 0.2 mol of A-3, 0.7 mol of B-1 and 0.1 mol of C-3 (the number of mols as a naphthalene skeleton), water in a reaction vessel with stirring. 5 mol of is added, and 0.9 mol of 37% formaldehyde is added dropwise at 80 ° C. over 3 hours. After completion of the dropping, the temperature was raised to 105 ° C and reacted for 8 hours, then cooled and adjusted to pH 8 with 50% sodium hydroxide, water was added to adjust the solid content to 20%, and cocondensation with a molecular weight of 25,000 was performed. I got a thing.

Preparation Example 7 (symbol D-7 of dispersant) 0.2 mol of A-4, 0.5 mol of B-2, 0.3 mol of C-1 and 5 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the dropping is completed, the temperature is raised to 105 ° C and reacted for 12 hours.
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 31,000.

Production Example 8 (symbol D-8 of dispersant) 0.1 mol of A-5, 0.5 mol of B-2, 0.4 mol of C-1 and 6 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 15 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 33,000.

Production Example 9 (symbol D-9 of dispersant) 0.3 mol of A-6, 0.3 mol of B-2, 0.4 mol of C-1 and 6 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 25 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 11,000.

Production Example 10 (symbol D-10 of dispersant) 0.1 mol of A-4, 0.6 mol of B-2, 0.3 mol of C-1 and 6 mol of water were charged in a reaction vessel with stirring, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 18 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 26,000.

Production Example 11 (Dispersant symbol D-11) A reaction vessel with stirring was charged with 0.1 mol of A-3, 0.1 mol of B-3, 0.6 mol of C-1 and 3 mol of water, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 25 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 30% to obtain a cocondensate having a molecular weight of 11,000.

Production Example 12 (Dispersant Code D-12) A reaction vessel with stirring was charged with 0.1 mol of A-7, 0.5 mol of B-2, 0.4 mol of C-1 and 7 mol of water, and 37% formaldehyde was added. 0.9 mol is added dropwise at 80 ° C. in 3 hours. After the completion of dropping, the temperature was raised to 105 ° C and reacted for 15 hours, then cooled to 50
The pH was adjusted to 8 with sodium hydroxide and water was added to adjust the solid content to 20% to obtain a cocondensate having a molecular weight of 41,000.

<Contents of Comparative Dispersant Used in Examples> Dispersant symbol NS; naphthalene-based dispersant (Mighty G-15
0: Kao Corporation Dispersant symbol PS; Naphthalene-based dispersant (Sunflow P
S; manufactured by Nippon Paper Industries Co., Ltd.).

The foaming agents used in the examples are shown below. <Contents of Foaming Agent Used in Examples> Emal D-3-D (manufactured by Kao Corporation).

The test conditions are shown below. <Test conditions> The test materials shown below were put into a small pin mixer and mixed for 15 seconds, and then the fluidity of the slurry and the stability of the foam were measured.

Hemihydrate gypsum: 1000 g Water: 600 g Dispersant: 0.1 g of gypsum (in terms of solid content)% by weight (included in water) Foam: 0.05 g / in a foaming machine using a 1% aqueous solution of Emal D-3-D Make 20 ml of foam and add 20 ml (400 ml).

Measurement of fluidity A cylindrical cone having a diameter of 50 mm and a height of 50 mm was filled with the slurry, and the spread (mm) after withdrawal was measured.

-Foam stability The foam stability (%) was obtained from the following formula from the specific gravity of each material by weighing the weight of the gypsum slurry per certain volume.

[0056]

[Equation 1]

The results of the examples are shown in Table 1.

[0058]

[Table 1]

[0059]

As is clear from the results shown in Table 1, the gypsum-water slurry dispersant of the present invention exhibits excellent foam stability. Therefore, improvement of the adhesiveness with paper (board) is expected. Also, since it has excellent fluidity, it is possible to improve productivity due to the water reduction effect.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 71/00 LQD C08L 71/00 LQD

Claims (12)

[Claims] 1. An oxyalkylene group having 1 to 3 carbon atoms 1
Formaldehyde co-condensation product of one or more kinds (A) selected from aromatic compounds introduced with 300 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group. Alternatively, a dispersant for a gypsum / water slurry containing a neutralized salt thereof as an essential component. 2. An oxyalkylene group having 1 to 3 carbon atoms 1
It has one or more kinds (A) selected from aromatic compounds introduced with 300 mol and one or more kinds (B) selected from aromatic compounds having a carboxyl group and a sulfonic acid group. 1 or 2 selected from aromatic compounds
A dispersant for gypsum / water slurry, which contains a formaldehyde co-condensate with at least one species (C) or a neutralized salt thereof as an essential component. 3. The reaction molar ratio of (A) and (B) is (A) / (B) =
The dispersant for gypsum / water slurry according to claim 1, which is 1-99 / 99-1. 4. The reaction molar ratio of (A), (B) and (C) is (A) /
The gypsum / water slurry dispersant according to claim 2, wherein (B) / (C) = 1 to 98/1 to 98/1 to 98. 5. An oxyalkylene group having 1 to 3 carbon atoms 1
The gypsum-water slurry dispersant according to any one of claims 1 to 4, wherein the aromatic compound introduced with 300 mol is a benzene ring derivative. 6. The dispersant for gypsum / water slurry according to claim 5, wherein the benzene ring derivative is an oxyalkylene group addition product of phenol. 7. The aromatic compound having a carboxyl group is a naphthalene ring or benzene ring derivative.
The dispersant for gypsum / water slurry according to any one of 1. 8. The dispersant for gypsum / water slurry according to claim 7, wherein the benzene ring derivative is a compound represented by the following general formula (a). Embedded image 9. The gypsum-water slurry dispersant according to claim 1, wherein the aromatic compound having a sulfonic acid group is a phenol derivative. 10. The dispersant for gypsum / water slurry according to claim 9, wherein the phenol derivative is phenolsulfonic acid. 11. The neutralization salt of the cocondensation product is a monovalent metal salt, 2
The dispersant for gypsum-water slurry according to any one of claims 1 to 10, which is a valent metal salt, an ammonium salt, an amine salt or a substituted amine salt. 12. The weight average molecular weight (gel permeation chromatography / sodium polystyrene sulfonate conversion) of the cocondensate or its neutralized salt is 3,000 to 100,000.
The gypsum-water slurry dispersant according to any one of claims 1 to 11.