KR20040105291A - Nanodispersed calcium carbonate in water and preparation method of the same - Google Patents

Abstract

PURPOSE: A nano-sized calcium carbonate(CaCO3) dispersed in water is provided, which has stability during diluting, heating and long-term by adsorbing polymer dispersant to the surface of ground CaCO3. CONSTITUTION: The CaCO3-dispersed solution is prepared by the following steps of: mixing 100pts.wt. of water, 1-50pts.wt. of CaCO3(0.001-10micrometer size) and 0.1-20pts.wt. of polymer dispersant; putting microbeads(0.1-3mm size), made of glass, ZrO2, Zr, TiO2 or CeO2, to the CaCO3 solution; milling mixtures in a metal or TiO2(or CeO2)-coated vessel(9) with an disk-shaped impeller(7) at a rate of 500-2000rpm, wherein the impeller reduces heat formed in stirring to prevent dispersed CaCO3 from agglomerating. The polymer dispersant having carboxylic group, 1-700 of degree of polymerization and 3,000-80,000 of molecular weight, is acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, alpha-hydroxyacrylic acid, crotonic acid, homopolymer thereof or copolymer thereof.

Description

Calcium carbonate nano dispersion in water and preparation method thereof {NANODISPERSED CALCIUM CARBONATE IN WATER AND PREPARATION METHOD OF THE SAME}

[Industrial use]

The present invention relates to a calcium carbonate nano dispersion in water and a method for preparing the same, and more particularly, the polymer dispersant in the aqueous solution is adsorbed on the ground calcium carbonate surface and excellent in stability to dilution, stability to heating and stability over time The present invention also relates to a calcium carbonate nano-aqueous dispersion which maintains a stable nano-sized particle size even when heated up to 95 ° C. and a method for producing the same.

[Prior art]

Calcium carbonate is largely divided into Ground Calcium Carbonate (GCC) and Precipitated Calcium Carbonate (PCC).

Calcium carbonate is a low cost material with excellent properties such as high whiteness, inertness, and incombustibility, and is widely used as an inorganic filler such as rubber, plastic, paint, paper, and adhesive.

In the paper industry, calcium carbonate is used as an environmentally friendly functional material that can eliminate the paper bleaching process because it removes residues of acid used in the papermaking process and increases the strength of paper making and prevents aging and yellowing.

Particularly, in the case of precipitated calcium carbonate (PCC), it is easy to control the particle size and distribution, and it is known that the use of precipitated calcium carbonate is excellent in the opacity and whiteness of the product. .

Recently, the construction of an on-site precipitated calcium carbonate (PCC) plant centered in the United States has lowered the cost of precipitated calcium carbonate (PCC), which has gradually favored precipitated calcium carbonate (PCC) instead of heavy calcium carbonate (GCC). It is a trend.

In the field of adhesives, in particular, ultrafine calcium carbonate (ultrafine PCC, particle size of 70 nm or less), which is surface-coated with fatty acid, is evenly dispersed in PVC plastisol and used as an automotive coating agent.

In the plastic field, calcium carbonate is used as a filler to impart viscosity, flow control, and dimensional stability, and is widely used in PVC, polyurethane, PE, epoxy, and other polyester resins.

In the plastics sector, the use rate of precipitated calcium carbonate (PCC) is growing rapidly at 8.4% per year, and it is known that the impact reinforcing effect of hard PVC is particularly effective in the case of ultra-fine calcium carbonate. The ultra fine calcium carbonate is surface treated with precipitated calcium carbonate (PCC) to increase the interfacial adhesion to the matrix (matrix) and maximize the impact reinforcement effect when the ultra fine calcium carbonate is evenly dispersed in the PVC matrix (matrix). You can expect

In particular, even microdispersion inside the resin is known to be absolutely important. In the paint and coating industries, the low price of calcium carbonate is used to enhance the attractiveness and product strength. Submerged calcium carbonate (PCC) of less than 2 microns is used for products requiring high brightness and gloss, and 6 micron for general purpose products. Heavy calcium carbonate (GCC) is used. In addition, calcium carbonate is applied to pharmaceuticals, cosmetics, household cleaners and the like.

When used in powder form, the shape, particle size, and particle size distribution of calcium carbonate are the criteria for providing functionality.In the case of application as a dispersion, not only the particle size of calcium carbonate itself, but also the dispersion level and dispersion stability of calcium carbonate in the medium are absolutely important. In particular, the dispersion level is expected to be excellent when the micro-dispersion is realized.

For example, in the paper industry, the development of nano-level dispersion technology that exceeds the conventional dispersion limits greatly increases the surface area of the dispersed calcium carbonate particles, maximizing the removal of inorganic acids remaining in paper and significantly improving the whiteness of the final product. As the volume by weight increases rapidly, the volume of calcium carbonate loading increases in the manufacture of pulp, so the volume increases rapidly by the weight of calcium carbonate, thus greatly increasing the amount of calcium carbonate, which is about 20% of the current natural pulp, greatly reducing the use of natural pulp. Can be.

Nano dispersions can also be applied to applications that require high brightness and high gloss, and are expected to be used in functional inorganic filler composites in plastics to enhance high gloss and whiteness, as well as to improve processability and mechanical properties.

Calcium carbonate dispersants are largely classified into inorganic and organic dispersants. Inorganic dispersants include pyrophosphate, tripolyphosphate, tripolyphosphate, trimetaphosphate, tetraphosphate, tetrametaphosphate, hexametaphosphate and the like, and zinc salts and silicates. However, the inorganic dispersant has a problem that the dispersion stability is poor and calcium carbonate precipitates because the dispersed phase is not sustained.

As an organic dispersing agent, polycarboxylates, such as polyacrylate and polymethacrylate, polymaleate, PVA, etc. are known. Polycarboxylates are the mainstream. As an example of the dispersion of calcium carbonate in water using a polymer dispersant, it is used to disperse calcium carbonate in the size of 1 micron using polyacrylate sodium salt, but when used in calcium carbonate in the size of 0.1 to 0.5 micron, dispersion stability is weak and viscosity is high. There is a high disadvantage.

PVA dispersants reported in Japanese Patent Application Laid-Open No. 60-262,862 not only have low dispersion efficiency but also have poor dispersion stability. Examples of using maleic acid copolymers as dispersants can be found in Japanese Patent Publication Nos. 54-36166, 53-144499, US Patent No. 4,175,066, US Patent No. 4,519,920, US Patent No. 4,555,557, and the like. The flow and viscosity characteristics of this 50% or more dispersion have been reported, but the dispersed size of calcium carbonate has not been reported. U.S. Patent No. 4,892,902 discloses an example in which a polymer dispersant including a carboxyl functional group, a phosphate dispersant, and anionic PVA are mixed, and examples of the above-mentioned patents are low viscosity and dispersion stability.

The present invention discloses the first technical achievements in the art of preparing a calcium carbonate nano-water dispersion having a relatively low concentration (less than 50%) of calcium carbonate (CaCO ₃ ) content which could not be achieved by conventional dispersion techniques.

The present invention is to solve the above-mentioned problems, an object of the present invention is that the aqueous dispersion of the polymer dispersant is adsorbed on the surface of the pulverized calcium carbonate and excellent in stability to dilution, stability to heating and time stability and also 95 It is to provide a calcium carbonate nano dispersion in water which maintains stable nano-sized particle size even when heated up to ℃.

It is also an object of the present invention to provide a method for preparing the calcium carbonate nano dispersion in water.

1 is a grinding mechanism diagram of the present invention.

* Description of the symbols for the main parts of the drawings *

1. Crushing Mechanism 3. Motor

5. Shaft 7. Impeller

9. Container

In order to achieve the above object, the present invention (a) 100 parts by weight of water; (b) 1 to 50 parts by weight of calcium carbonate; And (c) 0.1 to 20 parts by weight of a polymer dispersant.

The present invention also provides (a) 100 parts by weight of water; 1 to 50 parts by weight of calcium carbonate; And mixing 0.1 to 20 parts by weight of the polymer dispersant to prepare a mixture. And (b) it provides a method for preparing calcium carbonate nano dispersions comprising the step of stirring by adding a microbead (microbead) to the mixture.

Hereinafter, the present invention will be described in more detail.

Calcium carbonate nano dispersion in the present invention is (a) 100 parts by weight of water; (b) 1 to 50 parts by weight of calcium carbonate; And (c) 0.1 to 20 parts by weight of the polymer dispersant.

In addition, the (b) calcium carbonate may be preferably used either calcium carbonate or precipitated calcium carbonate having a primary particle size of 0.001 to 10 ㎛. If the size of the calcium carbonate primary particles exceeds 10 ㎛ it is not preferable because it takes a long time to prepare the nano-liquid aqueous solution.

In addition, the amount of the polymer dispersant added is preferably 1 to 20% by weight, more preferably 5 to 10% by weight based on calcium carbonate. When the amount of the polymer dispersant is less than 1% by weight relative to calcium carbonate, the size of the dispersed particles may be slightly increased to prepare a dispersion having a level of 100 nm, and even when the amount exceeds 50% by weight, excellent dispersion effect may be obtained. It is preferable to use 1 to 50% by weight of the polymer dispersant in consideration of the influence on the material to be applied later.

In addition, the (c) polymer dispersing agent preferably contains a carboxylic acid functional group, a polymer having a degree of polymerization of 1 to 700 and a weight average molecular weight of 3,000 to 80,000.

Specifically, the (c) polymer dispersant may be acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, α-hydroxy Homopolymers or copolymers thereof of acrylic acid (α-hydroxyacrylic acid), crotonic acid and salts thereof, or the acrylic acid, methacrylic acid, maleic acid, Fumaric acid, itaconic acid, α-hydroxyacrylic acid, crotonic acid and its salts, acrylates, methacrylates, acrylics Copolymers with amides, acetates, carbamates, imidazoles, styrene, ethylene, propylene, or vinyl chloride are preferred. Can be used.

The present inventors found that when the mixture of the polymer dispersant, calcium carbonate and water is dissolved by pulverizing and pulverizing the mixture of the calcium carbonate particles, the aqueous dispersion of the polymer dispersant in the aqueous solution is adsorbed on the pulverized calcium carbonate surface to obtain a stabilized nano dispersion. . In addition, the calcium carbonate nano dispersion in water maintains the dispersion stability semi-permanently at room temperature, even if the temperature is raised to 95 ℃ do not settle so do not settle, so it is excellent in storage stability.

It is preferable that the particle size of the calcium carbonate nano dispersion in water is 50 to 80 nm.

The present invention also provides (a) 100 parts by weight of water; 1-50 parts by weight of calcium carbonate; And mixing 0.1 to 20 parts by weight of the polymer dispersant to prepare a mixture. And (b) it provides a method for preparing calcium carbonate nano dispersions comprising the step of stirring by adding a microbead (microbead) to the mixture.

The material of the microbead is higher than the calcium carbonate, glass, zirconia (zirconia), zircon (zircone), titania (ceria) and the like is preferable.

In addition, the particle diameter of the microbeads is preferably 0.1 to 3 mm. The smaller the particle size of the microbeads, the easier it is to be pulverized into fine particles, and the higher the density and hardness of the microbead particles, the more excellent the grinding effect, thereby reducing the grinding time and particle size.

Since the inner wall of the container in which milling is performed is coated with titania or ceria, it is preferable to use a product manufactured to minimize wear phenomenon of the inner wall of the container during dispersion and grinding using microbeads.

2 is a view showing a grinding mechanism (1) used in the method for producing a calcium carbonate nano dispersion in the present invention.

The grinding mechanism consists of a motor 3, a shaft 5, a disk-shaped impeller 7 connected to the shaft, a container 9 made of metal or coated to improve the hardness of the surface.

The speed of the stirring motor 3 is preferably 500 to 2000 rpm. If the speed of the stirring motor 3 is less than 500 rpm, the time required for dispersing and pulverizing is too long, and it is not preferable. If the speed exceeds 2000 rpm, the time for dispersing and pulverizing is shortened, but the microbead and the container 9 It is not preferable because there is a risk of contamination due to damage.

The disk-shaped impeller (7) has the effect of minimizing the heat generated during stirring to prevent the re-agglomeration of dispersed calcium carbonate, and the longer the length of the shaft (5), the greater the energy consumption, so it is kept below the appropriate length Preferably, the diameter of the disk should be matched to the diameter of the container 9, but a space should be secured for the microbeads to rotate freely.

The smaller the size of the microbeads, the easier it is to be pulverized into fine particles. The higher the density and hardness, the better the pulverization effect, thereby reducing the grinding time and particle size. Since the inner wall of the container 9 in which the milling is performed is coated with titania or ceria, it is preferable to use a product manufactured to minimize wear phenomenon of the inner wall of the container 9 during dispersion and grinding using microbeads.

As described above, the calcium carbonate nano-aqueous dispersion of the present invention is adsorbed on the surface of the pulverized calcium carbonate in which the aqueous dispersion of the polymer dispersant is excellent in the stability against dilution, the stability against heating and the stability over time, and the temperature is raised to 95 ° C. Even if it keeps the particle size of nano size stable.

Hereinafter, preferred examples and comparative examples of the present invention are described. The following examples and comparative examples are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples and comparative examples.

(Example 1)

Dispersion Preparation

100 g of distilled water, 15 g of calcium carbonate (Belgium / Solva company, trade name SOCAL socal 31, particle size 70 nm) in a stainless steel container (SUS material, diameter 8 cm, height 12 cm, volume 0.5 l), polymer dispersant (Korea / Taechangsan) 0.75 g of trade name TPA400) and 50 g of zirconia beads having a diameter of 0.3 mm were added thereto.

The mixture in this vessel was ground at 1000 rpm for 15 hours with a stirrer equipped with a disk-shaped impeller 5 cm in diameter to obtain a dispersion.

Particle size measurement

The dispersion was measured using a Microtrac X100 manufactured by Honeywell (average of 3.48 times the refractive index of calcium carbonate, 1.33 and 60 seconds of water), and the volume average particle size was 54 nm.

(Examples 2 to 6)

Dispersions 2 to 6 vary the calcium carbonate content in sequence to 3, 5, 10, 20 and 30 g and other conditions were prepared according to Example 1 and their particle size measurements were in turn 56, 60, 62, 67 and 65 Nm.

(Example 7)

Dispersion liquid 7 was prepared using 100 g of calcium carbonate having a particle size of 50 nm without using distilled water.

(Example 8)

Dispersion liquid 8 was prepared using calcium carbonate (manufactured by HohoCalcium Co., Ltd., particle size: 70 nm), and other conditions were prepared in accordance with Example 1. The particle size measurement result was 62 nm.

(Example 9)

Dispersion liquid 9 was prepared using calcium carbonate (OMIYA Co., Ltd., particle size 2.5 nm) and the other conditions were prepared in accordance with Example 1, and the particle size measurement result thereof was 70 nm.

(Examples 10 to 11)

Dispersions 10 to 11 were tested at speeds of 1500 and 2000 rpm, respectively, and the other conditions were prepared according to Example 1, and the particle size measurements were all 54 nm.

(Examples 12 to 13)

Dispersions 12 to 13 had a content of microbeads of 30 and 70 g, respectively, and the other conditions were prepared according to Example 1, and the particle size measurements were in turn 55 and 56 nm.

(Examples 14 to 15)

Dispersions 14 to 15 used 0.45 and 3 g of the content of the dispersant, respectively, and the other conditions were prepared according to Example 1, and were 66 and 62 nm in turn as a result of particle size measurement.

(Examples 16 to 19)

Dispersions 16-19 used the weight average molecular weights of the dispersant in the order of 6000, 8000, 15000 and 30000 g / mol and the other conditions were prepared according to Example 1 and the particle size measurements were in turn 65, 67, 70 and 78 nm.

(Examples 20 to 27)

Dispersions 20 to 27 were used as the dispersant shown in Table 1 and the other conditions were prepared in accordance with Example 1 and the particle size measurement was in turn 64, 56, 63, 6, 70, 54 and 66 nm.

Example product name Monomer component Copolymer composition Molecular Weight (Mw) 20 TD4000 AA-MMA 70:30 5000 21 THC-F AA-MMA 60:40 4000 22 SY-3000A AA-acrylamide 70:30 5000 23 SY-3000B AA-acrylamide 50:50 5000 24 CONC-30 AA-PEO 90:10 4000 25 - AA-maleic acid 60:40 4000 26 - Maleic Anhydride-PP 50:50 5000 27 - Maleic Anhydride-α-olefin 50:50 5000

(Example 28)

Dispersion 28 was ground for 27 hours using glass beads having a diameter of 0.5 mm, and the other conditions were prepared according to Example 1, and had a particle size of 73 nm.

(Example 29)

In Example 1 were mixed so that a total of 5 ℓ of the same material as the ratio of using the Dyno-mill ^® KDL-pilot Shinmaru Enterprises Corporation, Japan dispersing device was obtained a dispersion for 2 hours to grind was measured result 54 ㎚.

(Example 30)

The same material as in Example 1 was placed in a propylene container and applied for 8 hours using a paint shaker to obtain a dispersion, which was 72 nm in size measurement.

(Comparative Example 1)

In 15 parts by weight of distilled water, 15 g of calcium carbonate (Belgium / Solval company name SOCAL socal 31) and 1.5 g of sodium lauryl sulfate (SLS) were ground in the same manner as in Example 1 to obtain Comparative Dispersion 1, and the particle size was 4.55. Μm.

(Comparative Examples 2 to 5)

Comparative dispersions 2 to 5 are dispersants containing sulfonate or sulfate groups (Comparative Example 2: SDBS, Comparative Example 3: DOSS, Comparative Example 4: Polyacrylate (trade name: disperBYK180), Comparative Example 5: polyut (trade name: EFKA4550)) was used, and the other conditions were prepared according to Example 1, and the particle size measurements were sequentially 3.43, 3.25, 3.73 and 4.11 mu m.

(Comparative Example 6)

The same material as in Example 1 was placed in a container equipped with a magnetic stirrer and stirred at 1000 rpm for 8 hours to obtain a comparative dispersion 6 with a particle size of 3.12 μm.

(Comparative Example 7)

The same material as in Example 1 was dispersed in Fisher Scientific's sonic dismembrator for 30 minutes, and the comparative dispersion 7 had a particle size of 1.55 µm.

(Comparative Example 8)

The same material as in Example 1 was ground for 8 hours by Ultimizer of Amstec Korea, and the particle size of Comparative Dispersion 8 was 1.71 µm.

Stability Test for Dilution

The particle size of the dispersion obtained by diluting the dispersion prepared in Example 1 with 10-fold volume of distilled water was 54 nm. However, the particle size of the dispersion obtained by diluting the dispersion prepared in Comparative Example 1 with 10-fold volume of distilled water was 15.2 μm.

Stability Test for Heating

The particle sizes of the dispersions prepared in Example 1 by heating them with water bath at 60 ° C. for 1, 3 and 5 hours were 64, 65 and 64 nm, respectively. However, the particle sizes of the dispersions prepared in Comparative Example 1, which were heated in a bath in water at 60 ° C. for 1, 3 and 5 hours, were 5.7, 6.2 and 5.5 μm, respectively.

Stability Test Over Time

The particle size of the dispersion prepared in Example 1 and stored at room temperature for 30 days was 58 nm. However, when the particle size of the dispersion prepared in Comparative Example 1 was stored at room temperature for 30 days, the particle size was 27.5 μm.

Therefore, it can be seen from the above experiment that the dispersion of calcium carbonate nanoparticles of the present invention has excellent particle stability as a nano-size, dilution stability, heating stability, and stability over time.

The calcium carbonate nano-aqueous dispersion of the present invention is adsorbed on the surface of the pulverized calcium carbonate in the aqueous dispersion of the aqueous dispersion, and excellent in stability against dilution, stability against heating and stability over time, and stable even when heated up to 95 ° C. Maintain particle size.

Claims (9)

(a) 100 parts by weight of water; (b) 1 to 50 parts by weight of calcium carbonate; And (c) 0.1 to 20 parts by weight of a polymer dispersant Calcium carbonate nano dispersion in water comprising a. The dispersion according to claim 1, wherein the calcium carbonate is selected from the group consisting of heavy calcium carbonate and precipitated calcium carbonate having a primary particle size of 0.001 to 10 µm. [Claim 2] The dispersion according to claim 1, wherein the (c) polymer dispersant is a polymer having a carboxylic acid functional group and having a degree of polymerization of 1 to 700 and a weight average molecular weight of 3,000 to 80,000. The method of claim 3, wherein the (c) polymer dispersant Acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, α-hydroxyacrylic acid, crotonic acid ( homopolymers of crotonic acid) and salts thereof or copolymers thereof Or the acrylic acid, methacrylic acid, maleic acid, maleic acid, fumaric acid, itaconic acid, α-hydroxyacrylic acid, croton Acids and salts thereof, acrylates, methacrylates, acrylamides, acetates, carbamates, imidazoles, styrene , Copolymers with ethylene, propylene or vinyl chloride Calcium carbonate nano dispersion in water, characterized in that. The dispersion of calcium carbonate nano-water according to claim 1, wherein the calcium carbonate nano-water dispersion has a particle size of 50 to 80 nm. (a) 100 parts by weight of water; 1-50 parts by weight of calcium carbonate; And 0.1 to 20 parts by weight of a polymer dispersant Mixing to prepare a mixture; And (b) adding a microbead to the mixture and stirring the mixture; Calcium carbonate nano dispersion solution preparation comprising a. The method of claim 6, wherein the material of the microbead is selected from the group consisting of glass, zirconia, zirconia, zircone, titania, and ceria. Manufacturing method. The method of claim 6, wherein the microbeads have a particle diameter of 0.1 to 3 mm. 7. The method of claim 6, wherein the stirring speed is 500 to 2000 rpm.