JPH05201724A - Ethylene glycol dispersion of crystalline calcium carbonate and crystalline calcium carbonate - Google Patents

Abstract

(57) [Abstract] [Purpose] Practically used as an additive to improve the friction coefficient of polyester films and fibers and to improve lubricity, and as various pigments, fillers, catalyst carriers, and functional powders. Disclosed is an ethylene glycol dispersion of crystalline calcium carbonate of high value and a crystalline calcium carbonate obtained from the dispersion. [Structure] At least one of a calcium compound or calcium metal selected from calcium oxide, calcium hydroxide and calcium halide is subjected to a carbonation reaction in a medium system containing 80% by weight or more of ethylene glycol to effect aging. Thus, an ethylene glycol dispersion of crystalline calcium carbonate is obtained. Further, crystalline calcium carbonate is obtained from the dispersion by filtration, washing, drying and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene glycol dispersion of crystalline calcium carbonate and crystalline calcium carbonate obtained from the dispersion. More specifically, the friction coefficient of polyester, particularly polyethylene terephthalate film and fiber. As an additive to improve the lubricity and improve the lubricity, and also as a filler for polymeric materials such as cosmetics, paper, paint pigments, rubber, plastics, sealants, dentifrices, pharmaceuticals, catalyst carriers and various functional powders. The present invention relates to an ethylene glycol dispersion of crystalline calcium carbonate, which has high practical utility as a body, and crystalline calcium carbonate obtained from the dispersion.

[0002]

2. Description of the Related Art Synthetic calcium carbonate is known in industry as spindle-shaped, colloidal-shaped, cubic-shaped, and columnar-shaped ones, all of which are produced by an aqueous carbonation reaction. .. These calcium carbonates belong to calcite or aragonite in terms of crystal structure, but vaterite or amorphous calcium carbonate is also known. In producing these, alcohols or a system to which alcohols are added is used. The carbonation reaction of is proposed. For example, disclosed in Japanese Examined Patent Publication No. 2-16244, a method for producing amorphous calcium carbonate by carrying out a carbonation reaction in an alcohol medium system, Journal of Adhesion Society of Japan Vol. 21, No. 10 (1985), a method for synthesizing vaterite in a methanol system, and a method for producing vaterite-based calcium carbonate in a system to which an organic medium is added, disclosed in JP-A-63-103824. Be done.

On the other hand, polyester, particularly polyethylene terephthalate, which is one of the most promising fields of application of the present invention, has excellent mechanical and chemical properties and is widely used in films, fibers, containers and the like. .. Among them, for magnetic tapes, thin film with smooth surface is required recently for high quality recording and long time recording, while workability is deteriorated due to poor lubrication in the manufacturing process or the product itself, and the product value is high. Have problems such as a decrease in

Conventionally, in order to solve such a problem,
A method has been adopted in which inorganic fine particles such as calcium carbonate, titanium oxide, silica, and talc are dispersed in glycol such as ethylene glycol and mixed in polyester to form protrusions on the film surface to improve lubricity. .. The conditions that these fine particles must satisfy are (1) the particle size is in the range of 0.1 to 2.0 μm, the particle size distribution is sharp, and (2) the dispersibility in a glycol medium is good. (3) Good affinity with polyester, and the like.

As a method for producing calcium carbonate used for such a purpose, precipitated calcium carbonate having a primary particle size of 0.1 μm or more and a dispersity of not less than the standard is prepared under a certain condition range by glycol. A method for producing by wet pulverization in a system is disclosed in Japanese Patent Publication No. 2-48174. Further, in JP-A 1-4239 and JP-A 1-4240, by preliminarily subjecting the precipitated calcium carbonate to a surface treatment with an α-, β-monoethylenically unsaturated carboxylic acid-based copolymer, Methods for improving dispersibility in glycol and affinity with polyester have been proposed.

[0006]

However, the glycol-based dispersions of calcium carbonate produced by these methods are, in any case, prepared by dispersing the precipitated calcium carbonate synthesized in an aqueous system through a pulverizing step in glycol. Therefore, not only is the manufacturing process complicated, but it is unavoidable to mix coarse particles and over-ground particles, and the shape and particle size distribution of the particles have not yet been sufficiently satisfactory.

In view of such circumstances, as a result of earnest studies by the present inventors, it was found that the conventional method of carrying out a carbonation reaction using a calcium compound or metallic calcium as a raw material in a medium system mainly composed of ethylene glycol and then aging it. Ethylene glycol of calcium carbonate having a novel shape with a secondary particle size of 0.1 to 2.0 μm and a sharp particle size distribution, and characteristics derived from them, which do not require a drying step and a crushing step, by a completely different method. The inventors have found that a dispersion can be produced, and have reached the present invention as a result of further intensive research. The object of the present invention is to improve the friction coefficient of polyester films and fibers and to improve lubricity, and also various Ethylene glycol component of crystalline calcium carbonate, which has high practical utility as a pigment, filler, catalyst carrier, and functional powder. To provide a crystalline calcium carbonate obtained from the body and the dispersion.

[0008]

According to the present invention, at least one of a calcium compound or metal calcium selected from calcium oxide, calcium hydroxide and calcium halide and 80 parts by weight of ethylene glycol are used. It was solved by an ethylene glycol dispersion of crystalline calcium carbonate produced through aging by a carbonation reaction in a medium system containing at least 100%.

It is preferable that the secondary particle size is in the range of 0.1 to 2.0 μm and the specific surface area is in the range of 20 to 300 m ² / g by the BET method.

The crystalline calcium carbonate produced from the above dispersion also solves the above problems.

[0011]

The crystalline calcium carbonate of the present invention, unlike the one obtained by the conventional method, is obtained as an ethylene glycol dispersion, so that it does not require a drying and crushing step when added to polyester, There is no concern about the inclusion of coarse particles due to agglomeration and fine particles due to over-milling. In particular, when calcium oxide is used as a raw material for production, the dispersion is composed only of ethylene glycol and calcium carbonate, so that it may adversely affect the polymer when used for polyester or the like without drying. Absent. Further, the morphology of the particles is mainly spherical, and the particle size thereof is 0.1 to 2.0 μm, which is extremely well matched to the target particle size. Furthermore, since it has a crystal structure of calcite, it can be said that it is an extremely stable inorganic powder during the manufacturing process or product. Therefore, the crystalline calcium carbonate of the present invention has extremely excellent characteristics as inorganic fine particles for improving the lubricity of the polyester film and the fiber, and the crystalline calcium carbonate is a pigment or filler such as a paint or sealant. It is also possible to use it as a cosmetic carrier, a dentifrice, and further as a catalyst carrier or a functional powder that takes advantage of the feature that the BET value is as high as 20 to 300 m ² / g.

The above-mentioned structure of the present invention and the saliency of its operation will be more clearly understood from the following description.

The crystalline calcium carbonate of the present invention is obtained by subjecting a calcium compound or metallic calcium as a raw material to a carbonation reaction in a medium system mainly composed of ethylene glycol,
After that, it is manufactured by being aged for a certain period. The raw materials used for the carbonation reaction are calcium compounds such as calcium oxide (quick lime), calcium hydroxide, basic calcium carbonate, calcium chloride, and metallic calcium without any particular limitation. A raw material slurry is prepared by suspending one or more of these raw materials in ethylene glycol. At this time, the total content of water or alcohols other than ethylene glycol is allowed to be 20% by weight or less in the ethylene glycol, but preferably 10% by weight.
It is below. If too much solvent other than ethylene glycol is mixed, not only calcium carbonate having the desired shape and properties cannot be obtained, but also when calcium carbonate is used for polyester or the like without being separated from ethylene glycol and dried, the polymer is adversely affected. Exert. Further, the calcium concentration of the slurry can be produced at 10% by weight or less in terms of the amount of metal. If the concentration is too high, the slurry gels and solidifies before the end of carbonation, and the carbonation cannot be completed completely. On the other hand, if the concentration is too low, the production efficiency is poor. From this, it can be said that the calcium concentration of the slurry is preferably 1.0 to 5.0% by weight. Carbonation gas may be used for the carbonation reaction, or a carbonate compound may be used. When carbon dioxide gas is used, it may be a pure gas obtained from a cylinder, but it is also possible to use a waste gas from a kiln in the production of quicklime, which is generally used industrially. Examples of the carbonate compound include ammonium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate and the like. In this case, mechanical stirring is necessary because gas stirring is not performed. The temperature during the carbonation reaction is not particularly limited, and it may be carried out at 0 to 70 ° C., which is easy to manufacture. When the carbonation reaction is carried out under such conditions, the raw material slurry has a p
H decreases to 7 to 8 and gels (when the slurry concentration of the raw material is low, it becomes a sol, but in the following, it is represented by a gel except for the portions of Examples). Since no remarkable peak was observed in the X-ray diffraction pattern of this gel, it is considered to be an amorphous phase.

Next, the gel is aged (crystallized). There is no particular limitation on the temperature during aging, but generally, the higher the temperature, the shorter time the gel disintegrates and slurries to complete the aging. For example, at room temperature for 2-3 days, 60-110 ℃ 1
It takes ~ 24 hours. The X-ray diffraction pattern of the calcium carbonate thus obtained is mostly composed of calcite diffraction peaks, and vaterite diffraction peaks are not or only slightly observed. The morphology observed with a transmission electron microscope is slightly changed depending on the concentration of ethylene glycol and the difference in impurity components. Normally, calcium carbonate consisting of fine particles with primary particles of 0.01 μm or less to 0.06 μm is radial. Alternatively, rhombohedral particles having a particle diameter of 0.1 to 2.0 μm are aggregated in a unique manner such as a radiative intergrowth and the secondary particle diameter is 0.1 to 2.0 μm.
It has a spherical to subspherical or bispherical shape. Furthermore, when the specific surface area is measured by the BET method, it is 20 to 30.
A value of 0 m ² / g is obtained.

Thus, as described above, the crystalline calcium carbonate of the present invention is obtained as an ethylene glycol dispersion, unlike the one obtained by the conventional method. Therefore, when it is added to the polyester, the steps of drying and crushing are performed. There is no need to worry about mixing coarse particles due to aggregation during drying and fine particles due to over-pulverization. Especially when manufactured using calcium oxide as a raw material, the dispersion is composed only of ethylene glycol and calcium carbonate, so when used in polyester without drying, the polymer is adversely affected by moisture etc. There is no. Further, the particle size is 0.1 to 2.0 μm, which is extremely well matched to the target particle size. Furthermore, since it has the crystal structure of calcite, it can be said that it is an extremely stable inorganic powder in the manufacturing process or product. Thus, the crystalline calcium carbonate ethylene glycol dispersion of the present invention has extremely excellent characteristics as inorganic fine particles for improving the lubricity of polyester films and fibers, and was obtained by taking out from the dispersion. Crystalline calcium carbonate is
In addition to pigments and fillers such as paints and sealants, they can also be used as catalyst carriers and functional powders that take advantage of the high BET value of 20 to 300 m ² / g.

[0016]

[Examples] Examples and comparative examples of the present invention will be described in more detail below.

Example 1 100 g of industrial slaked lime was added to a 3 liter capacity cylindrical flask containing 2 kg of ethylene glycol while stirring.
It was charged and the raw material slurry was adjusted. At this time, the temperature of the slurry was 30 ° C., the pH was 12.0, and the conductivity was 2.8 mS /
It was cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 67 minutes, the pH had fallen to 7.4, the conductivity had dropped to 0.4 mS / cm, and the slurry had gelled. The temperature at that time was 40 ° C.

While keeping this gel in the flask,
It was heated in a constant temperature water bath. The gel almost completely disintegrated in a few hours, and was slurried again. After 24 hours, this slurry was filtered, washed with methanol, and further dried at 110 ° C. When X-ray diffraction was performed on the obtained powder, a slight vaterite peak was observed and calcite was observed. It is a peak, and when the specific surface area was measured by the BET method, it was 1
A value of 41 m ² / g was obtained. In addition, as a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate having secondary particles of 0.3 to 1.0 μm in which primary particles having a diameter of about 0.01 μm are radially aggregated is confirmed. It was Figure 1
Shows the particle structure of calcium carbonate at a magnification of 20,000.

Example 2 The gel produced under the same conditions as in Example 1 was allowed to stand at room temperature. Two days later, the slurry obtained by collapsing the gel was filtered, washed with methanol, and dried at 110 ° C., and X-ray diffraction was performed on the obtained powder. As a result, a slight vaterite peak was observed. The other is the peak of calcite, and when the specific surface area was measured by the BET method, it was 165 m.
A value of ² / g was obtained. As a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate with secondary particles having a diameter of 0.5 to 1.2 μm, in which primary particles having a diameter of about 0.01 μm are radially aggregated, is confirmed. It was

Example 3 The gel prepared under the same conditions as in Example 1 was placed in a beaker.
When 0 g was taken and heated in a dryer maintained at 110 ° C., the gel disintegrated in 1 hour to form a slurry. The slurry is filtered, washed with methanol and then at 110 ° C.
X-ray diffraction of the powder obtained by drying at
Other than the slight vaterite peak, it was a calcite peak, and when the specific surface area was measured by the BET method, a value of 93 m ² / g was obtained. As a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate with secondary particles having a diameter of 0.5 to 1.5 μm, in which primary particles having a diameter of about 0.01 μm are radially aggregated, is confirmed. It was

Example 4 75 g of quicklime obtained by calcining industrial slaked lime at 700 ° C. for 3 hours was charged into a cylindrical flask having a capacity of 3 liters containing 2.0 kg of ethylene glycol with stirring to prepare a raw material slurry. It was adjusted. At this time, the temperature of the slurry is 28
C., pH was 11.3, and conductivity was 2.9 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. 63 minutes later, pH 7.2, conductivity 0.5 mS
/ Cm and the slurry gelled. The temperature at this time was 39 ° C.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 132 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or subspherical crystalline calcium carbonate having a secondary particle diameter of 0.2 to 0.7 μm, in which primary particles of about μm were radially aggregated.

Example 5 The gel produced under the same conditions as in Example 4 was allowed to stand at room temperature. Two days later, the slurry obtained by collapsing the gel was filtered, washed with methanol, and dried at 110 ° C., and X-ray diffraction of the obtained powder was performed. When the specific surface area was measured by the BET method, a value of 168 m ² / g was obtained. As a result of observation with a transmission electron microscope, primary particles having a diameter of about 0.01 μm are radially aggregated and the secondary particle diameter is 0.2.
Spherical or subspherical crystalline calcium carbonate of ˜0.7 μm was confirmed.

Example 6 The gel produced under the same conditions as in Example 4 was placed in a beaker.
When 0 g was taken and heated in a dryer maintained at 110 ° C., the gel disintegrated in 1 hour to form a slurry. The slurry is filtered, washed with methanol and then at 110 ° C.
X-ray diffraction of the powder obtained by drying at
It was composed only of the peaks of calcite, and when the specific surface area was measured by the BET method, a value of 106 m ² / g was obtained. Also, as a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate having secondary particles with a diameter of 0.3 to 1.1 μm, in which primary particles having a diameter of about 0.01 μm are radially aggregated, is confirmed. It was

Example 7 150 g of quicklime obtained by firing industrial slaked lime at 700 ° C. for 3 hours was put into a 3 liter capacity cylindrical flask containing 2.0 kg of ethylene glycol while stirring,
The raw material slurry was adjusted. At this time, the temperature of the slurry is 3
The temperature was 0 ° C., the pH was 12.2, and the conductivity was 2.8 mS / cm. While stirring this raw material slurry, the purity is 100%.
Carbon dioxide gas was introduced at a rate of 1 liter / min. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 70 minutes, the slurry gelled with the pH remaining at 10.4.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of the calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 113 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or subspherical crystalline calcium carbonate having a secondary particle diameter of 0.2 to 0.7 μm, in which primary particles of about μm were radially aggregated.

Example 8 40 g of quicklime obtained by calcining industrial slaked lime at 700 ° C. for 3 hours was charged into a cylindrical flask having a capacity of 3 liters containing 2.0 kg of ethylene glycol with stirring to prepare a raw material slurry. It was adjusted. At this time, the temperature of the slurry is 28
C., pH was 11.5, conductivity was 2.3 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 36 minutes, pH 7.1, conductivity 0.5 mS
/ Cm and the slurry gelled. The temperature at this time was 37.5 ° C.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of the calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 125 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or subspherical crystalline calcium carbonate having a secondary particle diameter of 0.2 to 0.7 μm, in which primary particles of about μm were radially aggregated.

Example 9 In a cylindrical flask having a capacity of 3 liter and containing 2.0 kg of ethylene glycol, industrial quicklime crushed to -200 mesh was charged with stirring to prepare a raw material slurry. At this time, the temperature of the slurry was 26 ° C., the pH was 11.4, and the conductivity was 3.0 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 70 minutes, the pH had dropped to 7.3, the conductivity had dropped to 0.6 mS / cm, and the slurry had gelled. The temperature at this time was 37 ° C.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of the calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 81 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
~ Primary particles of about 0.02 μm gathered in a radial pattern, 2
Spherical or subspherical crystalline calcium carbonate having a secondary particle size of 0.1 to 1.3 μm was confirmed.

Example 10 20 kg of ethylene glycol was mixed with industrial slaked lime at 700 ° C.
750 g of quicklime obtained by firing for 3 hours was charged and stirred, and then transferred to a stainless steel reaction container having a volume of 30 liters,
The raw material slurry was adjusted. At this time, the temperature of the slurry is 3
The temperature was 0 ° C., the pH was 11.3, and the conductivity was 3.3 mS / cm. A mixed gas with air having a carbon dioxide gas concentration of 30% by volume was introduced into this raw material slurry at a rate of 66.7 liters / minute. During the carbonation process, the pH showed an almost constant value, but the conductivity gradually decreased to 0.6 mS / cm, and after 60 minutes, the p
When H was 7.3, the slurry gelled. The temperature at that time is 4
It was 0 ° C.

The entire amount of this gel was heated to 60 ° C. 2 to
The gel almost completely disintegrated in 3 hours and was slurried again. 24
After a period of time, the slurry was filtered, washed with methanol, and dried at 110 ° C., and the powder obtained was subjected to X-ray diffraction.
When the specific surface area was measured by the ET method, it was 158 m ² / g
The value of was obtained. Also, as a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate having secondary particles of 0.2 to 0.8 μm in which primary particles having a diameter of about 0.01 μm are radially aggregated is confirmed. It was

Example 11 1 kg of industrial quicklime crushed to -200 mesh was added to 20 kg of ethylene glycol, stirred and transferred to a stainless reactor having a volume of 30 liters to prepare a raw material slurry. At this time, the temperature of the slurry was 28 ° C. and the pH was 11.
4. The conductivity was 3.5 mS / cm. This raw material slurry was mixed with 6% mixed gas of air with a carbon dioxide concentration of 30% by volume.
It was introduced at a rate of 6.7 l / min. During the carbonation process, the pH was almost constant, but the conductivity was 0.5 mS / c.
Gradually decreased to m, and after 64 minutes, the pH was 7.5 and the slurry gelled. The temperature at that time was 40 ° C.

The entire amount of this gel was heated to 60 ° C. 2 to
The gel almost completely disintegrated in 3 hours and was slurried again. 24
After a period of time, the slurry was filtered, washed with methanol, and dried at 110 ° C., and the powder obtained was subjected to X-ray diffraction.
When the specific surface area was measured by the ET method, it was 145 m ² / g
The value of was obtained. As a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate having secondary particles with a diameter of 0.1 to 1.5 μm, in which primary particles having a diameter of about 0.01 μm are radially aggregated, is confirmed. It was

Example 12 700 kg of industrial slaked lime was added to 800 kg of ethylene glycol.
30 kg of quicklime obtained by firing at 3 ° C. for 3 hours was charged and stirred, and then transferred to a stainless steel reaction container having a volume of 1.8 m ³ to prepare a raw material slurry. At this time, the temperature of the slurry is 30
C., pH was 12.0, conductivity was 3.5 mS / cm. A mixed gas of air having a carbon dioxide concentration of 30% by volume was introduced into this raw material slurry at a rate of 2700 liters / minute. During the carbonation process, the pH showed an almost constant value, but the conductivity gradually decreased to 1.0 mS / cm, and after 55 minutes, p
When the H was 7.8, the slurry gelled. The temperature at that time is 4
It was 5 ° C.

The entire amount of this gel was heated to 60 ° C. 2 to
The gel almost completely disintegrated in 3 hours and was slurried again. 24
After a period of time, the slurry was filtered, washed with methanol, and dried at 110 ° C., and the powder obtained was subjected to X-ray diffraction.
When the specific surface area was measured by the ET method, it was 133 m ² / g
The value of was obtained. As a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate with secondary particles having a diameter of 0.2 to 0.8 μm, in which primary particles having a diameter of about 0.01 μm are radially aggregated, is confirmed. It was

Example 13 In a cylindrical flask having a volume of 3 liters, 1.8 kg of ethylene glycol and 0.2 kg of diethylene glycol were mixed, and then industrial slaked lime was calcined at 700 ° C. for 3 hours, while stirring 75 g of quick lime obtained. It was charged and the raw material slurry was adjusted. At this time, the temperature of the slurry is 30 ° C. and the pH is 1
1.7, the conductivity was 2.1 mS / cm. While stirring this raw material slurry, 1% of 100% pure carbon dioxide gas was added.
It was introduced at a rate of 1 / min. 58 minutes after the start of carbonation, the slurry gelled, and at this time the pH was 7.3, the conductivity was 0.4 mS / cm, and the temperature was 41 ° C.

The gel was aged under the same conditions as in Example 1. The gel almost completely disintegrated in 4 hours and was slurried again. The slurry is filtered, washed with methanol,
Further, when the powder obtained by drying at 110 ° C. was subjected to X-ray diffraction, only a peak of calcite was observed, and B
When the specific surface area was measured by the ET method, a value of 54 m ² / g was obtained. As a result of observing with a transmission electron microscope,
It was a spherical or subspherical crystalline calcium carbonate having a secondary particle size of 0.4 to 0.9 μm, which was an aggregate of primary particles having a diameter of about 0.01 to 0.04 μm.

Example 14 200 g of industrial slaked lime was charged into a cylindrical flask having a capacity of 3 liters containing 2 kg of ethylene glycol while stirring to prepare a raw material slurry. At this time, the temperature of the slurry was 30 ° C., the pH was 12.0, and the conductivity was 3.0 mS / c.
It was m. Purity 1 while stirring this raw material slurry
00% carbon dioxide gas was introduced at a rate of 1 liter / min.
During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 68 minutes, the slurry gelled with the pH remaining at 10.4.

The gel was aged under the same conditions as in Example 1. The gel almost completely disintegrated in a few hours, and was slurried again. After 24 hours, this slurry was filtered, washed with methanol, and further dried at 110 ° C. When X-ray diffraction was performed on the obtained powder, only a diffraction peak of calcite was observed, which was measured by the BET method. When the specific surface area was measured, a value of 127 m ² / g was obtained. As a result of observation with a transmission electron microscope, primary particles having a diameter of about 0.01 μm are radially aggregated and the secondary particle diameter is 0.5 to 1.5 μm.
Spherical or subspherical crystalline calcium carbonate was confirmed.

Example 15 50 g of industrial slaked lime was charged into a cylindrical flask having a capacity of 3 liters containing 2 kg of ethylene glycol while stirring to prepare a raw material slurry. At this time, the temperature of the slurry was 30 ° C., the pH was 12.6, and the conductivity was 3.0 mS / cm.
Met. While stirring this raw material slurry, a purity of 10
0% carbon dioxide was introduced at a rate of 1 liter / min. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 35 minutes, pH 7.8, conductivity 0.
It decreased to 8 mS / cm, and the slurry changed to a sol state. The temperature at that time was 37 ° C.

The sol was aged under the same conditions as in Example 1. The sol almost returned to the original slurry state in 1 hour. When this slurry was filtered, washed with methanol, and dried at 110 ° C., the powder obtained was subjected to X-ray diffraction. As a result, only a slight vaterite peak was observed, which was a calcite peak. When the specific surface area was measured by the BET method, a value of 278 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or sub-spherical crystalline calcium carbonate having a secondary particle diameter of 0.5 to 1.0 μm, in which primary particles of about μm were radially aggregated.

Example 16 5 kg of industrial slaked lime was added to a cylindrical flask having a capacity of 3 liters in which 1.8 kg of ethylene glycol was mixed with 0.2 kg of water.
75 g of quicklime obtained by firing at 00 ° C. for 3 hours was added with stirring to prepare a raw material slurry. At this time, the temperature of the slurry was 35 ° C., the pH was 12.2, and the conductivity was 4.0.
It was mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 50 minutes, the pH is 7.
0, the conductivity decreased to 0.6 mS / cm, and the slurry gelled. The temperature at this time was 46 ° C.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 37 m ² / g was obtained. In addition, as a result of observation with a transmission electron microscope, spherical or sub-spherical crystalline calcium carbonate having secondary particle diameters of 0.6 to 1.0 μm, in which rhombohedral calcite particles were aggregated in a radial intergrowth, was confirmed. Was done.

Example 17 25 g of reagent metal calcium and 40 g of quick lime obtained by firing reagent slaked lime at 500 ° C. for 3 hours in a cylindrical flask having a capacity of 3 liters in which 1.8 kg of ethylene glycol was mixed with 0.2 kg of water. Was added with stirring to prepare a raw material slurry. At this time, the temperature of the slurry is 38 ° C and the pH is
Was 12.5 and the conductivity was 3.9 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. P in the carbonation process
H showed an almost constant value, but the conductivity gradually decreased.
After 50 minutes, the pH had dropped to 7.2, the conductivity had dropped to 0.6 mS / cm, and the slurry had gelled. The temperature at that time is 48
It was ℃.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of the calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 110 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or subspherical crystalline calcium carbonate having a secondary particle diameter of 0.5 to 0.9 μm, in which primary particles of about μm were radially aggregated.

Example 18 150 g of calcium chloride was put into a cylindrical flask having a capacity of 3 liters containing 1.8 kg of ethylene glycol while stirring and suspended. Next, 98 g of ammonium carbonate was dissolved in 200 g of water and gradually added to an ethylene glycol slurry of calcium chloride while stirring at 500 rpm to perform carbonation. Ammonium carbonate addition completed 2
After minutes, the slurry gelled.

The gel was aged under the same conditions as in Example 1. The X-ray diffraction peak of calcium carbonate formed after aging coincided with that of calcite, and when the specific surface area was measured by the BET method, a value of 98 m ² / g was obtained. As a result of observation with a transmission electron microscope, a diameter of 0.01
It was confirmed that spherical or sub-spherical crystalline calcium carbonate having a secondary particle diameter of 0.7 to 1.7 μm, in which primary particles of about μm were radially aggregated.

Example 19 1 kg of industrial slaked lime was added to 4 kg of ethylene glycol, and the mixture was stirred and transferred to a stainless reactor having a volume of 30 liters, and 15 kg of ethylene glycol was further added to prepare a raw material slurry. At this time, the temperature of the slurry is 30
C., pH was 12.4, conductivity was 3.3 mS / cm. A mixed gas with air having a carbon dioxide gas concentration of 30% by volume was introduced into this raw material slurry at a rate of 66.7 liters / minute. During the carbonation process, the pH showed a nearly constant value, but the conductivity gradually decreased to 0.8 mS / cm, and after 40 minutes, p
When H was 8.0, the slurry gelled. The temperature at that time is 3
It was 8 ° C.

The entire amount of this gel was heated to 60 ° C. 2 to
The gel almost completely disintegrated in 3 hours and was slurried again. 24
After a period of time, the slurry was filtered, washed with methanol, and dried at 110 ° C., and the powder obtained was subjected to X-ray diffraction.
When the specific surface area was measured by the ET method, it was 163 m ² / g
The value of was obtained. In addition, as a result of observation with a transmission electron microscope, spherical or subspherical crystalline calcium carbonate having secondary particles of 0.3 to 1.0 μm in which primary particles having a diameter of about 0.01 μm are radially aggregated is confirmed. It was

Example 20 In a cylindrical flask having a volume of 3 liters, 1.8 kg of ethylene glycol and 0.2 kg of methanol were mixed, and then 200 g of industrial slaked lime was charged with stirring to prepare a raw material slurry. At this time, the temperature of the slurry is 30 ° C. and the pH is 1
The conductivity was 2.0 and the conductivity was 3.0 mS / cm. While stirring this raw material slurry, 1% of 100% pure carbon dioxide gas was added.
It was introduced at a rate of 1 / min. 54 minutes after the start of carbonation, the slurry gelled, at which time the pH was 10.8.

The gel was aged under the same conditions as in Example 1. The gel almost completely disintegrated in 2 hours and was slurried again. The slurry is filtered, washed with methanol,
Further, when the powder obtained by drying at 110 ° C. was subjected to X-ray diffraction, only a peak of calcite was observed, and B
When the specific surface area was measured by the ET method, a value of 54 m ² / g was obtained. As a result of observing with a transmission electron microscope,
The crystalline calcium carbonate was a spherical or subspherical crystalline calcium carbonate having a diameter of 0.5 to 1.0 μm and composed of an aggregate of primary particles having a diameter of about 0.01 to 0.04 μm.

Example 21 In a cylindrical flask having a volume of 3 liters, 1.8 kg of ethylene glycol and 0.2 kg of diethylene glycol were mixed, and 200 g of industrial slaked lime was charged with stirring to prepare a raw material slurry. At this time, the temperature of the slurry is 30
C., pH was 12.0, conductivity was 2.0 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. 51 minutes after the start of carbonation, the slurry gelled and the pH at this time was 1
The conductivity was 1.0, the conductivity was 2.0 mS / cm, and the temperature was 51 ° C.

The gel was aged under the same conditions as in Example 1. The gel almost completely disintegrated in 4 hours and was slurried again. The slurry is filtered, washed with methanol,
Further, when the powder obtained by drying at 110 ° C. was subjected to X-ray diffraction, only a peak of calcite was observed, and B
When the specific surface area was measured by the ET method, a value of 44 m ² / g was obtained. As a result of observing with a transmission electron microscope,
It was a spherical or subspherical crystalline calcium carbonate having a secondary particle diameter of 0.7 to 1.0 μm, which was an aggregate of primary particles having a diameter of about 0.01 to 0.04 μm.

Comparative Example 1 In a cylindrical flask having a capacity of 3 liters, 1 kg of ethylene glycol and 1 kg of water were mixed, and then 200 g of industrial slaked lime was charged with stirring to prepare a raw material slurry. At this time,
The temperature of the slurry was 24.5 ° C., the pH was 12.0, and the conductivity was 5.6 mS / cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. After 70 minutes, the pH was 7.2 and the conductivity was 0.2 mS / cm, but no particular change in the properties of the slurry was observed. The temperature at that time was 44 ° C.

When this slurry was filtered, washed with methanol, and further dried at 110 ° C., the powder obtained was subjected to X-ray diffraction. The diffraction pattern coincided with that of calcite. When the surface area was measured, it was 18
A value of m ² / g was obtained. As a result of observation with a transmission electron microscope, it was columnar calcium carbonate in which calcite having a diameter of 0.02 to 0.2 μm was aggregated.

Comparative Example 2 In a cylindrical flask having a capacity of 3 liters, in which 1.4 kg of ethylene glycol was mixed with 0.6 kg of water, 20 g of industrial slaked lime was added.
0 g was added while stirring to prepare a raw material slurry.
At this time, the temperature of the slurry was 20 ° C., the pH was 13.0, and the conductivity was 4.4 mS / cm. While stirring this raw material slurry, 1 liter / liter of 100% pure carbon dioxide gas was added.
Introduced at the speed of minutes. During the carbonation process, the pH was almost constant, but the conductivity gradually decreased. 70 minutes later, pH
Of 7.2, the conductivity dropped to 1.2 mS / cm,
In particular, no change was observed in the properties of the slurry. The temperature at that time was 43 ° C.

When this slurry was filtered, washed with methanol, and dried at 110 ° C., the powder obtained was subjected to X-ray diffraction. The diffraction pattern of calcite was in agreement with that of the powder obtained by the BET method. When the surface area was measured, it was 8m
A value of ² / g was obtained. As a result of observation with a transmission electron microscope, it was a spindle-shaped calcium carbonate having a major axis of 1.0 to 2.5 μm.

Comparative Example 3 100 g of industrial slaked lime was charged into a cylindrical flask having a capacity of 3 liter containing 2 kg of diethylene glycol while stirring to prepare a raw material slurry. At this time, the temperature of the slurry is 30 ° C., the pH is 13.5, and the conductivity is 0.0 mS /
It was cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. However, even if carbon dioxide gas is introduced for 3 hours, the temperature,
No change in pH was observed, and no gelation was observed.
When this slurry was filtered and subjected to X-ray diffraction of the solid content dried at 110 ° C., it showed a diffraction pattern of calcium hydroxide.

Comparative Example 4 100 g of industrial slaked lime was charged into a cylindrical flask having a capacity of 3 liters containing 2 kg of propylene glycol with stirring to prepare a raw material slurry. At this time, the temperature of the slurry is 30 ° C., the pH is 13.0, and the conductivity is 0.1 mS /
It was cm. While stirring this raw material slurry, carbon dioxide gas having a purity of 100% was introduced at a rate of 1 liter / minute. However, even if carbon dioxide gas is introduced for 3 hours, the temperature,
No change in pH was observed, and no gelation was observed.
When this slurry was filtered and subjected to X-ray diffraction of the solid content dried at 110 ° C., it showed a diffraction pattern of calcium hydroxide.

[0061]

As is clear from the above description,
The present invention has the following effects.

The crystalline calcium carbonate of the present invention, unlike the one obtained by the conventional method, is obtained as an ethylene glycol dispersion, and therefore does not require a step of drying and pulverizing when added to the polyester, There is no fear of mixing coarse particles due to aggregation during drying and fine particles due to over-milling. Further, the morphology of the particles is mainly spherical, and the particle size thereof is 0.1 to 2.0 μm, which is extremely well matched to the target particle size. Furthermore, since it has a crystal structure of calcite, it is extremely stable in the manufacturing process or product. Especially when produced using calcium oxide as a raw material, the dispersion is composed of only ethylene glycol and calcium carbonate and does not contain other components, so when used for polyester or the like without drying,
It does not adversely affect the polymer. Furthermore, in the reuse of ethylene glycol after taking out calcium carbonate at a high concentration or as a dry powder from the dispersion,
It is an essential condition that there is no increase in impurities such as water,
The effect of using calcium oxide as a raw material is remarkable.

The crystalline calcium carbonate of the present invention has extremely excellent characteristics as an additive for improving the coefficient of friction of polyester films and fibers and improving the lubricity. Furthermore, the crystalline calcium carbonate obtained by taking it out from the ethylene glycol dispersion and drying it is promising not only for the above-mentioned applications but also for various pigments, fillers, catalyst carriers, and functional powders, and has practical utility value. high.

[Brief description of drawings]

FIG. 1 is a transmission electron micrograph at a magnification of 20,000 showing the particle structure of the calcium carbonate produced in Example 1.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Asaba 840 Tsukui, Yokosuka City, Kanagawa Prefecture

Claims (3)

[Claims] 1. A carbonation reaction of at least one of a calcium compound selected from calcium oxide, calcium hydroxide and calcium halide or calcium metal in a medium system containing 80% by weight or more of ethylene glycol, An ethylene glycol dispersion of crystalline calcium carbonate produced through aging. 2. The ethylene of crystalline calcium carbonate according to claim 1, wherein the secondary particle size is in the range of 0.1 to 2.0 μm and the specific surface area is in the range of 20 to 300 m ² / g by the BET method. Glycol dispersion. 3. Crystalline calcium carbonate produced from the dispersion according to claim 1 or 2.