JP2984786B2 - High weathering extender and water-based coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extender for water-based paints and an aqueous paint composition, and more particularly to a highly weather-resistant extender, an aqueous paint composition and various water-based paints as an extender. Film gloss, weather resistance,
The present invention relates to calcium carbonate particles imparting water resistance and a method for producing the same.

[0002]

2. Description of the Related Art Calcium carbonate is widely used in applications such as paper, rubber, plastics, paints and inks, and plays a large role as an extender for paints. Recently, as environmental issues have been highlighted, from the standpoint of environmental protection, the trend toward water-based solvent-based paints has been increasing,
Film performance comparable to solvent-based paints (high gloss, high film strength,
A water-based paint having high water resistance, high weather resistance, etc.) has been required. As a calcium carbonate extender pigment that meets these expectations from the viewpoint of high gloss, high gloss cannot be obtained unless it is a colloidal calcium carbonate of the submicron class, as is known from experience with compound solvent-based coatings.

[0003] Most of the conventional colloidal calcium carbonate is
In order to improve the affinity for rubber, plastic, solvent-based paint, etc., a lipophilic surface coating is provided. For example, a slurry prepared by introducing a carbon dioxide gas into an aqueous suspension of calcium hydroxide and then chemically coated to obtain a slurry of calcium carbonate, which is treated with fatty acid soap, resin acid soap or the like to form a surface coating, is made of calcium carbonate particles. Since the surface is lipophilic, it is not very suitable as an extender for water-based paints.

[0004] In addition, some pigments which are commercially available as a high gloss calcium carbonate extender for aqueous systems and have excellent pigment dispersibility and gloss have appeared. However, high dispersion and high gloss in aqueous systems have been developed. Due to the importance of the treatment, the treated calcium carbonate is too hydrophilic, and when used for building exterior wall coatings, which is the main use of the calcium carbonate extender for high gloss, it has weather resistance and water resistance. However, there is a strong demand in the coatings industry for a high-gloss extender pigment that is more water- and weather-resistant than conventional ones.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly glossy water-based coating composition having excellent weather resistance and water resistance and a highly dispersible extender pigment therefor. An object of the present invention is to provide calcium carbonate particles and a method for producing the same.

[0006]

Accordingly, the results of repeated studies aimed at obtaining a high-gloss extender for water-based paints having excellent dispersibility, high gloss, and excellent water resistance and weather resistance compared to conventional products. (A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer, and (B) a nonionic phosphate ester type surfactant. It has been found that when calcium carbonate particles having various kinds of surface coating agents adsorbed thereon are used as extenders for water-based paints, coating films having high gloss, high weather resistance and high water resistance can be obtained.

The present invention relates to (A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer, and (B) a nonionic phosphate ester. A surface coating agent for calcium carbonate particles comprising a surfactant.

The present invention relates to (A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer, and (B) a nonionic phosphate ester. In a water-based coating composition containing an extender in a surface-coated calcium carbonate particle having a surface-active agent adsorbed on its surface and an aqueous paint extender comprising the calcium carbonate particle, and having a volume fraction of 35% or less, A water-based paint composition containing an extender for a water-based paint in a range of 5 to 30% by weight.

The present invention relates to (A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer; The method for producing calcium carbonate particles according to any one of claims 2 to 7, wherein the surface is coated with a nonionic phosphate ester type surfactant and then dehydrated.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Surface Coating Agent (A) Sulfonated aliphatic diene-based polymer, which is one type of surface coating agent used in the present invention, and sulfonation of aliphatic diene with a polymerizable monomer The copolymer salt (A) is generally a water-soluble polymer salt, and is strongly adsorbed on calcium carbonate to enhance pigment dispersibility, and has a function of contributing to a higher gloss of a coating film of the water-based coating composition. Have something.

As the aliphatic diene, an aliphatic diene having 4 to 7 carbon atoms, specifically 1,3-butadiene, 1,2
-Butadiene, 1,2-pentadiene, 1,3-pentadiene, 2,3-pentadiene, isoprene, 1,2-
Hexadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,3-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3
-Butadiene, 2-ethyl-1,3-butadiene, 1,
2-heptadiene, 1,3-heptadiene, 1,4-heptadiene, 1,5-heptadiene, 1,6-heptadiene, 2,3-heptadiene, 2,5-heptadiene,
In addition to linear aliphatic dienes such as 3,4-heptadiene and 3,5-heptadiene, various branched dienes having 4 to 7 carbon atoms are preferably used, such as 1,3-butadiene, isoprene and 1,3-butadiene. Pentadiene, more preferably isoprene, can be used.

As the monomer polymerizable with the aliphatic diene, various monomers having an olefinic double bond can be used. Specifically, aliphatic, alicyclic and aromatic hydrocarbons having an olefinic double bond, unsaturated amides, unsaturated alcohols, unsaturated esters, unsaturated nitriles, unsaturated carboxylic acids and esters thereof, Unsaturated, aliphatic, alicyclic, aromatic alcohols or phenols such as saturated sulfonic acids and esters thereof, or alcohols or diols having an amino group, an ester group, a nitrile group, a carboxylic acid group, or a sulfonic acid group. Can be used. An unsaturated carboxylic acid such as acrylic acid and methacrylic acid, and an aromatic vinyl monomer such as styrene, α-methylstyrene, vinyl naphthalene and vinyl biphenyl are preferred in view of the dispersibility of the surface-coated calcium carbonate particles as a pigment. As the monomer capable of being polymerized with the aliphatic diene, one kind may be used alone, or two or more kinds may be used in optional ratio.

The cationic species forming a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer include alkali metals, alkaline earth metals, and ammonium. , Amines and the like are preferred.

The sulfonated aliphatic diene polymer salt or the sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer has a polymerization average molecular weight of 500 to 100.
000, the sulfonation ratio of the aliphatic diene moiety is 10 to 80.
%, And specifically, in the case of commercially available products, Dynaflow-K, Dynaflow-Z, Dynaflow-P, SC-7
0 (both products are products of Nippon Synthetic Rubber Co., Ltd.).

Surface Coating Agent (B) The nonionic phosphate ester type surfactant (B), which is another type of surface coating agent used in the present invention, is used in combination with the surface coating agent (A) to form a surface. It not only suppresses the dry agglomeration of the coated calcium carbonate particles, but also imparts a suitable lipophilic property and contributes to the high weather resistance and high water resistance of the coating film. The nonionic phosphate ester type surfactant (B) is usually hardly soluble in water. However, when the nonionic phosphate type surfactant (B) is used in combination with the surface coating agent (A), both can be mixed, so that it is easy to use. The surface coating agent (B) can be emulsified and used. That is, in the surface coating treatment with the surface coating agent (A) alone, the calcium carbonate particles are strongly dried and aggregated, and the dispersibility is deteriorated. However, when used in combination with the surface coating agent (B), it is possible to prevent dry aggregation of the calcium carbonate particles.

As nonionic phosphate ester type surfactants, H.I. L. B. Is preferably in the range of 5 to 10, and specific examples thereof include nonionic phosphate ester type surfactants represented by the following formulas (1) to (3).

Formula (1) RO— (CH ₂ CH ₂ O) _n (PO) (OH) ₂ : Monoester Formula (2) (RO— (CH ₂ CH ₂ O) _n ) ₂ (PO) (OH) : diester formula _{(3) (RO- (CH 2} CH 2 O) n) 3 (PO): triesters preferably non-ionic phosphoric acid ester type surfactant,
A nonionic anionic surfactant obtained by subjecting an ether type nonionic surfactant to a phosphoric esterification, usually containing a monoester of the above formula (1) and a diester of the formula (2) as main components and a small amount of the formula (3) ) Is a mixture containing the triester.

Surface-Coated Calcium Carbonate Particles (Extended Pigment) The particle size of the surface-coated calcium carbonate particles (extended pigment) of the present invention is not particularly limited, but is usually 0.05 to 0.5.
It is in the range of μm. The amount of the surface coating agent adsorbed is not particularly limited, but is usually polymerizable with (A) the sulfonated aliphatic diene-based polymer salt or aliphatic diene with respect to 100 parts by weight of the solid content of calcium carbonate. The total amount of the sulfonated copolymer salt with the monomer and (B) the nonionic phosphate ester type surfactant is 0.1 to 10 parts by weight, and the weight of (A) and (B) is The ratio is in the range from 1: 9 to 9: 1.

Production of Surface-Coated Calcium Carbonate Particles The surface-coated calcium carbonate particles of the present invention are synthesized calcium carbonate by a chemical production method obtained by introducing carbon dioxide gas into an aqueous suspension of calcium hydroxide which is generally used in industry. (A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer in a slurry having an average particle size of 0.05 to 0.5 μm; (B) A total of 0.1 to 10 parts by weight, preferably 3 to 10 parts by weight of the surface coating agent, based on 100 parts by weight of calcium carbonate solids, of two types of surface coating agents of the nonionic phosphate ester type surfactant. After adding 5 parts by weight and the combined use ratio of the surface coating agents (A) and (B) in the range of 1: 9 to 9: 1 to perform surface coating, the mixture was dehydrated by a filter press by an ordinary method, Dry and crush It can be produced by.

If the total amount of the surface coating agent is less than 0.3 parts by weight, the surface of the calcium carbonate particles cannot be sufficiently coated,
Satisfactory dispersibility and gloss cannot be obtained. Also,
If the amount is more than 5 parts by weight, the amount of the coating agent is excessive with respect to the calcium carbonate, and the free coating agent that does not adsorb to the surface of the calcium carbonate particles remains, which is not only wasteful, but also causes a decrease in water resistance.

The size of the calcium carbonate particles in the calcium carbonate slurry used as the raw material is preferably from 0.05 to 0.5 μm, preferably from 0.07 to 0 μm in view of the balance between pigment dispersibility and gloss. .3 μm is preferred. 0.
When the particle size is less than 05 μm, the surface activity of the calcium carbonate particles increases, and the pigment dispersibility decreases even when the surface coating treatment is performed.
In some cases, high gloss cannot be obtained or the viscosity of the coating composition becomes too high. At 0.5 μm or more, there is no problem in pigment dispersibility, but even if the pigment is sufficiently dispersed, there is a limit in increasing the gloss of the coating film. Do not fit. The particle size refers to the length of one side calculated by assuming cubic particles from the BET specific surface area, or the average value of the major axis and minor axis of the particles observed by electron microscopy.

Water-based coating composition The water-based coating composition prepared using the surface-coated calcium carbonate particles (highly weather-resistant extender pigment) of the present invention is prepared using a conventionally used calcium carbonate pigment for high gloss. Water resistance and weather resistance of the coating film are superior to those of the prepared coating compositions. Specifically, the content of the highly weather-resistant extender pigment of the present invention is 5 to 30% by weight in the water-based paint, and the total pigment volume ratio of the highly weather-resistant extender pigment of the present invention and other pigments is 35% or less. By preparing a water-based coating composition for coating formulation, a coating film having high gloss and excellent water resistance and weather resistance can be obtained.

The water-based coating composition of the present invention contains a dispersant, which is generally used in the formulation of a coating, as long as the above conditions are satisfied.
Any of an antifoaming agent, a viscosity modifier, a coloring pigment, a preservative, and the like can be added.

[0024]

By using the surface-coated calcium carbonate particles (enrichment pigment) of the present invention in, for example, blending of a water-based paint composition for an architectural top coat or a single-layer elastic paint, gloss, water resistance and weather resistance can be obtained. A coating film having excellent properties and the like can be obtained.

[0025]

The present invention will be described below in more detail with reference to Examples, Comparative Examples and Application Examples.

Example 1 A 100 L compound vessel was charged with 50 kg of lime milk at 20 ° C. and 8% by weight, and 30% carbon dioxide gas was blown in at a rate of 0.3 L / min with stirring to form a suspension. The reaction was continued until the conductivity dropped to a second level and became stable. After the reaction,
Heat aging is continued at 80 ° C. until a predetermined particle diameter is reached, and the average particle diameter is 0.15 μm and the BET specific surface area is 11.2 m ² / g.
To obtain a calcium carbonate slurry. While stirring the obtained slurry, 810 g of a 20% aqueous solution of sodium salt of a 10% isoprene / acrylic acid copolymer and 540 g of a 5% aqueous solution of phosphanol RS410 were mixed in advance, and the entire amount of a solution was added. The mixture was stirred and mixed for 30 minutes to uniformly coat the calcium carbonate particles. The coated calcium carbonate slurry was dehydrated with a filter press, dried and pulverized by a usual method to obtain 5 kg of surface-coated calcium carbonate particles (highly weather-resistant pigment).

Examples 2 to 7 In the same manner as in Example 1, a predetermined particle size (described in the calcium carbonate base particle size in Table 1) obtained by a carbon dioxide compounding method in which carbon dioxide gas is blown into lime milk. Using calcium carbonate as a base material, the surface was coated with various surface coating agents and coating amounts (described in Table 1) to obtain 5 kg of a highly weather-resistant extender pigment.

Comparative Examples 1 to 4 In the same manner as in Example 1, the obtained calcium carbonate base material was coated with various surface coating agents alone, or was left untreated (no coating treatment). After finishing, 5 kg of an extender pigment was obtained. (Described in Table 1)

[0029]

[Table 1]

Examples of application to water-based paints Example samples (highly weather-resistant extender pigments), comparative samples and commercially available high-gloss extender pigments obtained according to the present invention are applied to a top coat for building interior and exterior, and dispersed. The properties, gloss, weather resistance, water resistance and the like were examined. Table 3 shows the results.

(1) Glossy synthetic resin emulsion paint formulation (top coat formulation for building interior and exterior)

[0032]

[Table 2]

(2) Pigment dispersion method Simple dispersion using a table-top TK homomixer (manufactured by Tokushu Kika) (3) Preparation method of paint (a) Mill base dispersion Disperser: TK homomixer (vane diameter 40 mm, tabletop type) Dispersion container: 300 ml polycup Charge amount: The above-mentioned number of revolutions: 2500 rpm Dispersion time: 25 minutes (b) Preparation paint The above-mentioned mill base dispersion is added to the emulsion dispersion prepared in advance, and the mixture is stirred and mixed. I got

Disperser: TK homomixer (40 mm blade, tabletop type) Formulation: 1500 rpm × 5 minutes (4) Description of test method (a) Dispersibility (JIS K5400 ^{1990 4,} 7, 1) Dispersion of mill-based dispersion The degree was measured with a tub gauge.

(B) Viscosity (JIS K5400 ¹⁹⁹⁰ 4,5,3) The viscosity of the prepared paint was measured one day and five days after preparation.

Viscometer: BM type viscometer Measurement temperature: 25 ° C. Rotation speed: 6 rpm and 60 rpm (c) Specular gloss (JIS K5400 ^1990, July 6) Formulated emulsion paint is coated on a black measuring paper with a 4 mil film applicator. After drying in a room for 2 days, the gloss was measured.

Gloss meter: Gloss meter GM3D type, manufactured by Murakami Technical Research Institute, Measurement angle: 20 °, 60 ° (d) Concealment (conforms to JIS K5400 ¹⁹⁹⁰ 7.2) Concealment ratio measurement paper and a 4-mil film applicator After drying in a room for 2 days, the diffuse reflectance was measured, and the hiding ratio was determined.

Gloss meter: Gloss meter GM3D type, manufactured by Murakami Technical Laboratory Measurement angle: 45 °, 0 ° Filter: green

[0039]

(Equation 1)

(E) Weather resistance Weather resistance tester: Sunshine carbon arc lamp accelerated weather resistance tester Irradiation time: 500 hours and 1000 hours

[0041]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09C 1/02 C09C 3/10 C09D 5/00 C09D 7/12

Claims (10)

(57) [Claims] 1. A sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer, and (B) a nonionic phosphate ester type interface. A surface coating agent for calcium carbonate particles comprising an activator. 2. A sulfonated aliphatic diene polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer, and (B) a nonionic phosphate ester type interface. Surface-coated calcium carbonate particles with an activator adsorbed on the surface. 3. The surface-coated calcium carbonate particles according to claim 2, having a particle size of 0.05 to 0.5 μm. 4. The calcium carbonate particles according to claim 2, wherein (A) the aliphatic diene is an aliphatic diene having 4 to 7 carbon atoms. 5. The nonionic phosphate ester type surfactant (B) is a nonionic phosphate ester type surfactant represented by the following formulas (1) to (3): L.
B. The calcium carbonate particles according to any one of claims 2 to 4, wherein the surfactant is a nonionic phosphate ester type surfactant in the range of 5 to 10. Formula (1) RO- (CH ₂ CH ₂ O) _n (PO) (OH) ₂ Formula (2) (RO- (CH ₂ CH ₂ O) _n ) ₂ (PO) (OH) Formula (3) (RO _{- (CH 2 CH 2 O)} n) 3 (PO) n represents an average addition number of moles of ethylene oxide, R represents an alkyl group or an alkyl phenol group having 8 to 30 carbon atoms. 6. A sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer with respect to 100 parts by weight of calcium carbonate solid content, B) The total amount of the nonionic phosphate ester type surfactant is 0.1 to 10 parts by weight, and the weight ratio of (A) to (B) is in the range of 1: 9 to 9: 1. The calcium carbonate particles according to claim 2. 7. An extender for water-based paints comprising the calcium carbonate particles according to claim 2. Description: 8. A water-based coating composition containing the extender pigment according to claim 7 in a range of 5 to 30% by weight in a water-based paint composition containing the extender pigment in a volume ratio of 35% or less. 9. A slurry of calcium carbonate particles,
(A) a sulfonated aliphatic diene-based polymer salt or a sulfonated copolymer salt of an aliphatic diene and a polymerizable monomer and (B) a nonionic phosphate ester type surfactant. The method for producing calcium carbonate particles according to any one of claims 2 to 7, wherein the calcium carbonate particles are dehydrated after surface coating. 10. The method for producing calcium carbonate particles according to claim 9, wherein a slurry obtained by introducing carbon dioxide gas into an aqueous suspension of calcium hydroxide is used as the slurry of calcium carbonate particles.