JPH02149331A - Dispersing stabilizer for inorganic powder for use in water - Google Patents

Abstract

PURPOSE:To improve dispersing stability of inorganic powder of high concentration in water by mixing polyoxyalkylene derivatives of specific composition with copolymers of maleic anhydrides or maleic acid salt to prepare dispersing stabilizer for inorganic powder in water. CONSTITUTION:Polyoxyalkylene derivatives represented by the general formula I (B: compound residue with 2-8 hydroxyl group, AO: 2-18 C oxyalkylene group, R<1>: 2-5 C unsaturated hydrocarbon group, R<2>: 1-40 C hydrocarbon group, a: 0-1000, b: 0-1000, c: 0-1000, l: 1-8, m: 0-2, n: 0-7, l+m+n=2-8, al+bm+cn=1-1000, m/l+n<=1/2) and maleic acids are caused to copolymerize in the presence of radical catalysts. Copolymers thus produced are used as dispersing stabilizers in water for inorganic powder.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a dispersion stabilizer in water for various inorganic powders such as calcium carbonate and titanium oxide, and more specifically to a stabilizer for dispersing inorganic powders in water at high concentrations and stably. Regarding dispersion stabilizers.

[Conventional technology]

Dispersions of inorganic powders in water, that is, water slurries, are used in various industrial fields, and are used in large quantities as white pigments for paper, leather, and the like. The most typical example is calcium carbonate fine powder, which is used in many industrial fields as an inexpensive white pigment, regardless of whether it is heavy or light. It is widely used as a pigment.

In these fields, the conventional method was to transport inorganic powder to the site of use, where it was dispersed in water. However, various problems caused by transporting the powder, such as dust In addition to economic issues such as the need for new mixing equipment on the user's side, there is an increasing demand for manufacturers to prepare water slurry in advance and transport it to the user as a slurry. There is. In this case, in order to reduce transportation costs, a water slurry of high concentration and low viscosity of K is required, and a water slurry that does not cause hard sedimentation during transportation is required.

Further, such a water slurry having high concentration, low viscosity, and excellent sedimentation stability is strongly desired from the viewpoint of not only transportation but also use thereof. That is, for example, when applying a water slurry such as the calcium carbonate fine powder to paper as a white pigment, in order to increase the efficiency of the drying process after coating, a water slurry with as little water as possible, that is, a high concentration and low viscosity, is used. In addition, from the viewpoint of facilitating the coating and improving coating film properties, the high concentration, low viscosity water slurry is required to have excellent sedimentation stability.

Conventionally, in order to meet these demands, dispersion stabilizers have been used to stably disperse inorganic powders in water.To date, many surfactants have been used as dispersion stabilizers, such as polyacrylic acid and its copolymers. Salts of copolymers of maleic anhydride and α-olefins have been proposed.

[The invention tries to solve i! ! ! However, with the conventional dispersion stabilizers as described above, it is difficult to obtain an aqueous slurry of inorganic powder, especially calcium carbonate fine powder, which has high concentration, low viscosity, and excellent sedimentation stability and can be advantageously applied to various fields. That was difficult.

Therefore, an object of the present invention is to provide an industrially valuable dispersion stabilizer in water that can stably disperse various inorganic powders such as calcium carbonate fine powder in water at high concentration and low viscosity for a long period of time. shall be.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the inventors discovered that a copolymer of a special polyoxyalkylene derivative and maleic acids, typified by maleic anhydride, can be used to make powders such as calcium carbonate fine powder. The present invention was completed based on the knowledge that the present invention exhibits excellent performance as a dispersion stabilizer for various inorganic powders in water compared to the conventional ones, and can fully achieve the above object.

That is, the present invention provides a copolymer of (i) a polyoxyalkylene derivative represented by the following general formula CI) and (i) one or more maleic acids selected from maleic anhydride, maleic acid, and maleic acid groups. This is an inorganic powder dispersion stabilizer in water.

(However, B is a residue of a compound having 2 to 8 hydroxyl groups,
AO is an oxyfulkylene group having 2 to 18 carbon atoms, R1 is an unsaturated hydrocarbon group having 2 to 5 carbon atoms, and R2 is an oxyfulkylene group having 1 to 4 carbon atoms.
0 hydrocarbon groups, a = 0-1000, b = 0-10
00, e=O~1000, L=1~8, m=O~2,
n = O ~ 7, t + m + n = 2 ~ 8, a l + b m
+c n 〜1〜10001m/(t+n)≦1/
It is 2. ) That is, the dispersion stabilizer of the present invention has the general formula (i1
It is a copolymer of a polyoxyalkylene derivative represented by the formula and maleic acids selected from maleic anhydride, maleic acid, and salts thereof, and the polyoxyalkylene derivative unit and the maleic acid unit may each be used alone, or two types may be used. It may be a mixture of more than one species.

The ratio of the polyoxyalkylene derivative unit to the maleic acid unit is not particularly limited, but the equivalent ratio based on the polymerizable double bond is about 7:3 to 3, particularly approximately 1:
1 is preferred. The average molecular weight of the copolymer is also not limited, but it is preferably 1.000 to 2,000,000, particularly 3,000 to 300,00.
0 is preferred.

In the general formula (i) Ic, compounds having 2 to 8 hydroxyl groups with B as a residue include ethylene glycol, propylene glycol, zuchinglyfur, dobcylene glycol, octadecylene gelicol, and neohentyl. Glycol, styrene glycol, glycerin, diglycerin, polyglycerin, trimethylolethane, trimethylolpropane, 1,3.5-pentanetriol,
Erythritol, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, sorbite,
Polyhydric alcohols such as sorbitol glycerin condensate, adonisol, 7-bitol, xylitol, mannitol; Polyhydric phenols such as catechol, resorcinol, human quinone, phloroglucin; xylose, arabinose, ribose, rhamnose, glucose, fructose , galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose,
Sugars such as sucrose, raffinose, gentianose, melezitose; partially etherified products and partially esterified products thereof.

The oxyalkylene group having 2 to 18 carbon atoms represented by AO includes oxyethylene group, oxypropylene group, oxybutylene group, oxytetramethylene group, oxystyrene group, oxyalkylene group, oxytetramethylene group,
There are oxyhexadecylene groups, oxyoctadecylene groups, etc., and they may be adducts of one type alone or a mixture of two or more types, and the adducts of 2'PM or more may be random adducts or block adducts. You can.

The unsaturated hydrocarbon group having 2 to 5 carbon atoms represented by R1 includes polymerizable unsaturated hydrocarbon groups such as vinyl group, allyl group, methallyl group, 3-butenyl group, 4-pentenyl group, and 3-methyl-3-butenyl group. Some have saturated bonds.

The hydrocarbon group represented by R2 has 1 to 40 carbon atoms,
Particularly preferred are hydrocarbon groups having 1 to 24 carbon atoms, such as methyl, ethyl, propyl, isopropyl,
Butyl group, isobutyl group, tert-butyl group, amyl group, in7myl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, intridecyl group, tetradecyl tin ,
hexadecyl group, isohexadecyl group, octadecyl group, in-octadecyl group, oleyl group, octyldodecyl group, tocosyl group, tesyltetradecyl group, benzyl group,
cresyl group, butylphenyl group, dibutylphanyl group,
octylphenyl group, nonylphenyl group, dodecylphenyl group, dioctylphenyl group, dinonylphenyl group,
Examples include styrenated phenyl groups and naphthyl groups.

At least one R1 must be contained in the unit represented by the general formula [I]. The number of carbon atoms in R1 is related to polymerization reactivity, and if it is too large, the reactivity will be poor, so the above range is appropriate. When the number of R1 represented by t is 1, a linear copolymer can be obtained, and when it is 2 or more, a crosslinked copolymer can be obtained. In this case, the value of t is arbitrary t
By selecting K, the degree of crosslinking can be adjusted and an arbitrary copolymer can be obtained.

The reason why a l + b m + c n is limited to 1000 or less is because it is difficult to manufacture anything exceeding this value.

Regarding the relationship between t, m, and n, it is fine as long as m is in the range of O to 2, but if it is too large compared to (t+n), crosslinked ester will be generated during the reaction and gelation will occur, making it difficult to adjust. Not desirable because it is difficult. Therefore, the relationship between 4% m and n needs to be m/(t+n)≦1/2.

The number of carbon atoms in AO can be arbitrarily selected within the range of 2 to 18, but R
In combination with 2, the ratio of hydrophilic groups to lipophilic groups can be adjusted.

On the other hand, among maleic acids that form a copolymer with the polyoxyalkylene derivative of general formula [I], examples of maleic acid salts include ammonia; methylamine, ethylamine,
Propylamine, butylamine, hexylamine, octylamine, 2-ethylhexylamine, nonylamine, decylamine, dotecylamine, intridecylamine, tetradecylamine, hexadecylamine, inhexadecylamine, stearylamine, instearylamine, oleylamine, linoleamine , octyldodecylamine, tocodylamine, decyltetradecylamine, aniline, and other monoamines; ethylenedi7mine, tetramethylenediamine, dodecylpropylenediamine,
Polyamines such as octadecyl-p-pylene diamine, oleylpropylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine; monoethanolamine, jetanolamine, triethanolamine, monoimpropylene diamine, sillable panolamine , triisopropanolamine, flukanolamines such as fullkylene oxide adducts of the above monoamines and diamines; lysine,
There are salts of amino acids such as fulginine and histidine; alkali metals such as lithium, sodium, and potassium; and alkaline earth metals such as magnesium and calcium.
Depending on the types of Rl and R2, one type and the degree of neutralization can be selected so that the copolymer is dissolved or dispersed in water. Lower amines such as ammonia, methylamine, and alkanolamine, and alkali metals are preferably used.

The polymer can be easily obtained by copolymerizing a polyoxyalkylene derivative of the general formula [■] with maleic anhydride, maleic acid, or a maleate salt using a radical catalyst such as a peroxide. When the maleic acid unit is maleic acid or a salt thereof, the polyoxyalkylene derivative of general formula (i) and maleic anhydride are copolymerized using a radical catalyst, and then hydrolyzed, and this is further converted into a salt. Conversion is preferable because a product with a higher molecular weight can be obtained.

Further, during copolymerization, copolymerizable components such as styrene, α-olefin, and vinyl acetate may be mixed and copolymerized.

The copolymer thus obtained has B, AO, parts.

Copolymers with a wide range of properties can be obtained by appropriately changing R2,2%m, n and maleic acid units, but copolymers that are arbitrarily soluble in water or copolymers that are not soluble in water at all. In many cases, a copolymer that dissolves in water to some extent provides more favorable results as a dispersion stabilizer than a copolymer.

Inorganic powders to be dispersed in this invention are not particularly limited, but include kaolin, aluminum silicate, clay, talc, mica, asbestos powder, calcium silicate, sericite, silicates such as bentonite, calcium carbonate,
Carbonates such as magnesium carbonate, barium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, metal oxides such as magnesia, alumina, antimony oxide, titanium oxide, white carbon, diatomaceous earth, and iron oxide, aluminum hydroxide, Metal hydroxides such as magnesium hydroxide, iron hydroxide, and metatitanic acid, as well as silicon carbide, silicon nitride, boron nitride, zirconia, barium titanate, satin white, carbon black, and graphite.

The average particle size of these inorganic powders varies greatly depending on the type, but is generally 100 μm or less, usually 0.5 μm or less.
It is about 1 to 50 μm.

The amount of dispersion stabilizer used when preparing an aqueous slurry of inorganic powder using the dispersion stabilizer of this invention is as follows:
The amount is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight. If the amount is less than 0.011 parts by weight, the effect is insufficient, and if it is used in excess of 10 parts by weight, the effect will not increase and it is economically disadvantageous.

Any method can be used to prepare the water slurry of inorganic powder, but
Generally, a predetermined amount of the dispersion stabilizer of the present invention is dissolved in water, and inorganic powder is added to the mixture while stirring, or a cake is prepared by producing inorganic powder such as light calcium carbonate or various inorganic salts in water and then dewatering it. A method is used in which a dispersion stabilizer is added to the mixture to form a slurry.

In addition, in the above-mentioned 1llll production, in addition to the dispersion stabilizer of the present invention, other aqueous dispersants such as anionic,
Nonionic surfactants such as olefin-maleic acid coelectrolyte salts, (meth)acrylic acid polymer salts, naphthalene sulfonic acid formaldehyde condensates, condensed phosphates, polyoxyethylene oleyl ether, and Oxyethylene sorbitan monooleate or the like may be used in combination. By using this combination, better results may be obtained in terms of the dispersibility and dispersion stability of the fine powder and the redispersibility of the precipitate.

〔Effect of the invention〕

As described above, the aqueous dispersion stabilizer for inorganic powder of the present invention not only has excellent dispersibility and dispersion stability of the inorganic powder but also has long-term storage stability by using the salt of the copolymer as an active ingredient. Even if it settles later, it is possible to prepare an aqueous dispersion in which the sediment is soft and has good redispersibility.

〔Example〕

Below, the present invention will be explained more specifically by describing examples thereof. The dispersion stability and redispersibility of the water dispersions prepared in the following Examples and Comparative Examples were measured and evaluated using the following methods.

<Dispersion Stability> After preparing the aqueous dispersion, it was immediately placed in a 50 m/scale emulsification test tube and left standing in a constant temperature room at 25C.

The dispersion state after 24 hours was observed and evaluated as follows.

◎: Powder did not settle at all.

○: Powder is slightly settled.

△: The powder has settled considerably.

×: The powder has completely settled.

Redispersibility> After preparing vI4 of the water dispersion, immediately put it into a 50-scale emulsification test tube, leave it in a constant temperature room at 25C, and examine the hardness and redispersibility of the sediment after 30 days. It was evaluated as follows.

◎: Well dispersed.

O: Disperses when water is stirred.

△: Soft and easily crumbles when poked with a spatula.

×: Hard (does not crumble easily even when poked with a spatula).

In addition, in the following examples, the compounds shown in A to K in Table 1 were used as the aqueous dispersion stabilizer of this invention, but as long as they are defined in the claims, only the actual examples are used. Needless to say, it is not limited.

Example 1 Using titanium oxide with an average particle size of 0.3 μm as an inorganic powder and using the dispersion stabilizer of the present invention shown in Table 1 and a conventionally known dispersion stabilizer as a comparison as a dispersion stabilizer, f+
Mix a predetermined amount of water, a dispersion stabilizer, and an inorganic powder so that the concentration of the dispersion stabilizer is 1.2% by weight and the inorganic powder is 45% by weight (i%), and put this into a sand mill [Igarashi Machine Manufacturing ■]. The dispersion in water according to the present invention was prepared by grinding and mixing for 3 hours.The dispersion stability and redispersibility of these dispersions in water are shown in Table 2.

Example 2: Light calcium carbonate with an average particle size of 0.1 μm was used as the inorganic powder, and the dispersion stabilizers listed in Table 1 of the present invention and the comparative dispersion stabilizers were used as the dispersion stabilizer. A predetermined amount of water, a dispersion stabilizer, and an inorganic powder are mixed so that the concentration shown in Table 3 is 60 weight φ of the inorganic powder, and this is mixed using a homogenizer in 2. OOOrp
The inventive and comparative dispersions were prepared by mixing between m and 10 f+. Table 3 shows the dispersion stability and redispersibility of the obtained aqueous dispersion.

=20- Example 3゜Dispersion was carried out using magnesium hydroxide powder with an average particle size of 0.2 μm as the inorganic powder, and using the dispersion stabilizers listed in Table 1 of the present invention and the comparative dispersion stabilizers as the dispersion stabilizers. A predetermined amount of water, a dispersion stabilizer, and an inorganic powder are mixed so that the stabilizer has a concentration listed in Table 4 and the inorganic powder has a concentration of 45% by weight, and the mixture is heated to 2.00 O using a homogenizer.
Inventive and comparative aqueous dispersions were prepared by mixing for 15 minutes at rpm. Dispersion stability and redispersibility are shown in Table 4.

Real side 1° Carbon black with an average particle size of 0.05 μm was used as the inorganic powder, and the dispersion stabilizers listed in Table 1 of the present invention and the comparative dispersion stabilizers were used as the dispersion stabilizer. Mix a predetermined amount of water, a dispersion stabilizer, and an inorganic powder so that the concentration listed in the table is 40% by weight of the inorganic powder, and mix this with a homogenizer to 2.00 Orp.
Inventive and comparative aqueous dispersions were prepared by mixing for 15 minutes. Dispersion stability and redispersibility are shown in Table 5.

As can be seen in the above examples, it is clear that the dispersion stabilizer of the present invention exhibits excellent performance as a dispersion stabilizer for various inorganic powders in water.

=24- −25=

Claims (1)

[Claims] 1. A combination of (i) a polyoxyalkylene derivative represented by the following general formula [I] and (ii) one or more maleic acids selected from maleic anhydride, maleic acid, and maleic acid salts. An inorganic powder dispersion stabilizer in water consisting of a polymer. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・[I] (However, B is the residue of a compound with 2 to 8 hydroxyl groups,
AO is an oxyalkylene group having 2 to 18 carbon atoms, R^1 is an unsaturated hydrocarbon group having 2 to 5 carbon atoms, and R^2 is 1 carbon number.
~40 hydrocarbon groups, a=0-1000, b=0-10
00, c=0-1000, l=1-8, m=0-2, n
=0~7, l+m+n=2~8, al+bm+cn=1
~1000, m/(l+n)≦1/2. )