JPH05295166A - Plastic molding - Google Patents

Abstract

(57) [Summary] [Purpose] In order to enhance the functionality such as strength of the plastic molded product and to enhance its added value, calcium carbonate with very good dispersibility is manufactured as a filler, and further, if necessary, further. Provided is a plastic molded article containing the calcium carbonate, the affinity for which is improved by surface treatment. [Structure] A molded product containing calcium carbonate produced in an ethylene glycol system, which has been surface-treated with a phosphoric acid ester or the like, if necessary, and then contained in a plastic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calcium carbonate-containing plastic molded product produced in an ethylene glycol system. More specifically, the present inventors have previously filed Japanese Patent Application No. 3-164477. It relates to the method for producing calcium carbonate in an ethylene glycol system according to No. 1, and is based on calcium carbonate having an extremely uniform particle size distribution, which can be said to be the most excellent inorganic filler with no dry agglomeration. is there.

Since this calcium carbonate is produced in an ethylene glycol system, it can be used as it is without being made into a dry powder in polyester, but it is made into a dry powder to be contained in other plastics. There is a need. In that case, ethylene glycol and the calcium carbonate are separated by a cracks system (manufactured by Hosokawa Micron Co., Ltd.) or a method of washing with methanol after filtration and further drying at 110 ° C. to obtain powdered calcium carbonate.

The calcium carbonate has very good dispersibility, probably because it is produced in an ethylene glycol system. The particle diameter of secondary particles is in the range of 0.1 to 2.0 μm, the specific surface area is 20 to 300 m ² / g by the BET method, and the commonly used calcium carbonate particles of 0.1 to 2.0 μm. Has a very high value compared with the specific surface area of ² to 15 m ² / g.

This is because the calcium carbonate is usually 1
As secondary particles, fine particles of 0.01 μm or less to 0.06 μm are aggregated in a unique radial intergrowth-like manner and have a spherical to subspherical or bispherical shape of 0.1 to 2.0 μm. It seems that it is because it was done.

The above-mentioned crack system will be briefly described below.

When the stock solution is supplied to a heating tube whose jacket is heated with steam or the like, the solvent content of the stock solution entering from the inlet reaches the boiling point due to sensible heat. When boiling starts, the flow velocity in the tube rapidly increases due to the evaporation of the solvent, resulting in a turbulent flow and the solvent in the stock solution evaporates. Since the outlet of the heating tube is connected to the powder collection chamber kept in vacuum, the pressure inside the heating tube decreases as it approaches the outlet, and the evaporation of the solvent further progresses and the evaporated solvent vapor is further heated and overheated. It becomes steam. As a result, the flow velocity in the pipe increases and reaches a velocity close to the speed of sound. On the other hand, the powder in the undiluted solution becomes a dry powder in a short time until the end of evaporation of the solvent, so there is little aggregation and it is injected and collected in the powder collection chamber together with superheated steam, and the solvent collected separately is recycled. Then it can be used.

In this way, the powdered calcium carbonate may be used as it is, but in order to further improve the affinity with plastics, phosphate ester, ethylene-propylene copolymer or α-, β -It is also effective to perform surface treatment with a copolymer such as monoethylenically unsaturated carboxylic acid.

The calcium carbonate obtained in the present invention is used for thermosetting resins such as plastics such as polyester, melamine epoxy, polyurethane or alkylbenzene, and polyethylene, polypropylene, polystyrene, vinyl chloride, vinyl acetate, ABS (acrylonitrile-butadienestyrene). Copolymer) and other high-value-added additives for thermoplastic resins.

The present invention relates to a plastic molded product containing these calcium carbonate, which is used in other industries such as rubber, paint, ink,
As an additive for sealants, papers or cosmetics, toothpaste, pharmaceuticals, etc., it can be effectively used in each field, which has not been heretofore available.

[0010]

2. Description of the Related Art Synthetic calcium carbonate is known in the industry as spindle-shaped, cubic-shaped, and column-shaped ones, all of which are produced by carrying out a carbonation reaction in an aqueous system. These calcium carbonates belong to calcite or aragonite in terms of crystal structure, and vaterite or amorphous calcium carbonate is also known in the non-aqueous system.

The calcite-type calcium carbonate of the present invention, which is to be kneaded and utilized, is lighter, tougher, and can be molded into various shapes as compared with metals, ceramics, wood, etc., and is beautiful, extremely stable, and rusty. It is a relatively inexpensive material that does not corrode or corrode. There are many types of plastics. For example, polyvinyl chloride has good electrical insulation and excellent chemical resistance, but is poor in heat resistance. Polyethylene has good electrical insulation, chemical resistance, and is light and easy to mold. Further, polypropylene has characteristics such as high mechanical strength, light weight, and relatively high heat resistance. Furthermore, polyester, especially polyethylene terephthalate, is mechanically
It has excellent chemical properties and is widely used for films, fibers, containers, etc. By adding a filler such as calcium carbonate to these plastics, impact strength, abrasion resistance, dimensional stability, coefficient of thermal expansion, electrical properties, heat resistance, and chemical resistance can be improved.

Conventionally, inorganic fine particles such as calcium carbonate, titanium oxide, silica and talc have been dispersed in plastics such as polyvinyl chloride, polyethylene and polypropylene as well as polyester. Conditions that these fine particles must satisfy are: (1) finer particle size and sharper particle size distribution (2) good dispersibility in plastics (3) affinity with plastics There are things such as being good.

As a method for producing calcium carbonate used for such a purpose, the primary particle diameter is 0.04 to 0.0
8 μm colloidal calcium carbonate is surface-treated with an alkali metal salt of a fatty acid or a resin acid, or calcium carbonate having a primary particle size of 0.1 μm or more and a dispersity of not less than the standard is suspended in calcium hydroxide. When it is produced by reacting a suspension with carbon dioxide, and when it is used for polyester, for example, it is wet pulverized in a glycol system under a certain condition range, or calcium carbonate is preliminarily mixed with α- and β-monoethylenic monomers. There has been proposed a method of improving dispersibility in glycol and affinity with polyester by performing surface treatment with a saturated carboxylic acid copolymer.

[0014]

However, in the conventional calcium carbonate synthesized by adding carbon dioxide gas to an aqueous suspension of calcium hydroxide, various surface treatments are applied to the calcium carbonate to determine the mechanical dispersion means. However, probably because the particle size and dispersibility are not appropriate, it is unavoidable to mix coarse particles or over-ground particles due to aggregation, and it has not been possible to obtain a sufficiently satisfactory particle shape and particle size distribution.

In view of such circumstances, the present invention has a finer particle size and a sharp particle size distribution at the time of filling the plastic in order to enhance the functionality such as strength of the plastic molded product and improve the added value thereof. , Which has good dispersibility in plastics and, if necessary, good affinity with plastics, is used to produce calcium carbonate of high practical value, and plastic moldings containing this The challenge is to provide the body.

[0016]

[Means for Solving the Problems] As a result of intensive studies by the present inventors, a treatment agent having a high affinity with a calcite-type calcium carbonate produced in an ethylene glycol system without being treated on a plastic to be filled. We succeeded in solving the above problems by using it after surface treatment.

In particular, a carbonation reaction is carried out in a medium system mainly composed of ethylene glycol using at least one of a calcium compound selected from calcium oxide, calcium hydroxide, calcium halide and the like, or metallic calcium as a raw material, and thereafter. The secondary particle size is 0.1 to 2.0 μm due to a completely different method of aging.
It was found that an ethylene glycol dispersion of calcium carbonate having a novel shape of m, a sharp particle size distribution, and characteristics derived from these can be produced, and further, carbon dioxide separated from ethylene glycol by a cracks system or by a method such as filtration. By washing calcium with methanol or the like and then drying at 110 to 120 ° C., an easily dispersible powder having a very small cohesive property, which has never been considered, was obtained. As a result of further study, the as-manufactured ethylene glycol-based product was mainly used as a filler for polyester, and a dry untreated product, or the untreated product was a phosphoric acid ester, an ethylene-propylene copolymer, or the like. It has been found that the surface-treated product exhibits remarkable functionality mainly as a filler for polyethylene and polypropylene.

The calcium carbonate powder has a secondary particle size of 0.
It is in the range of 1 to 2.0 μm and has a specific surface area of 2 by the BET method.
The range of 0 to 300 m ² / g is suitable.

[0019]

The calcium carbonate of the present invention, unlike the one obtained by the conventional method, is produced in ethylene glycol, so that it can be added to the polyester without being dried, and it is possible to form coarse particles by dry agglomeration and fine particles by over-milling. There is no worry of mixing. Further, the morphology of the particles is mainly spherical, and the particle size is also appropriate, being 0.1 to 2.0 μm. Furthermore, since it has the crystal structure of calcite, it can be said that it is an extremely stable inorganic powder as a manufacturing process or product. Therefore, the 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 dry powder of the calcium carbonate is used for other plastics with or without surface treatment. For example, highly functional physical properties can be obtained for polyvinyl chloride, polyethylene, or polypropylene.

In addition to pigments and fillers such as paints, sealants, and inks, cosmetics, dentifrices, and catalyst carriers and functional powders that make use of the characteristic that the BET value is as high as 20 to 300 m ² / g. It is also possible to use.

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

The calcium carbonate plastic compact according to the present invention is produced 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, and then aging for a certain period of time. A material obtained by kneading calcium carbonate with a plastic and used for the carbonation reaction is a calcium compound such as calcium oxide, calcium hydroxide or calcium chloride or metallic calcium without any particular limitation. A raw material slurry is prepared by suspending one or more of these raw materials in ethylene glycol. The ethylene glycol at this time may contain a total of 20% by weight or less of water or alcohols other than ethylene glycol, but preferably 10% by weight or less. Further, the calcium concentration of the slurry can be produced at 10% by weight or less in terms of metal amount. If the concentration is too high, the slurry will gel and solidify before the end of carbonation, so that the carbonation cannot be completely completed, while if the concentration is too low, the production efficiency will be poor.
From this, the calcium concentration of the slurry is 1.0 to 5.
It can be said that 0% by weight is desirable. Carbon dioxide may be used for the carbonation reaction, or a carbonate compound may be used. When carbon dioxide gas is used, pure gas obtained from a cylinder may be used, but it is also possible to use waste gas from the kiln during the production of quick lime 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 pH of the raw material slurry falls to 7 to 8 and gels (when the slurry concentration of the raw material is low, it becomes a sol. Exclude gel to represent). 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 almost 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 of the impure component. Usually, the primary particles of calcium carbonate are from 0.01 μm or less to 0.06 μm in a radial pattern. Alternatively, rhombohedral particles having a particle diameter of 0.1 to 2.0 μm are aggregated in a unique manner such as radial intergrowth and have a secondary particle diameter of 0.1 to 2.0 μm, which is spherical to subspherical. is doing. Furthermore, when the specific surface area is measured by the BET method, a value of 20 to 300 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 an aqueous dispersion obtained by a conventional method, and therefore it is used as it is in a polyester without being dried. Further, it can be further processed by the cracks system method, or after being filtered, washed with methanol, and dried at 110 to 120 ° C., as it is without treatment, or with a phosphoric ester,
Treated with ethylene-propylene copolymer, acrylic acid, etc. and kneaded with polyethylene, polypropylene, etc., or calcium carbonate is made into an aqueous suspension and surface-treated with fatty acid soda or resin acid soda and kneaded with polyvinyl chloride. By doing so, a plastic molding having excellent physical properties can be obtained.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 100 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 2.8 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.
In the carbonation process, PH showed an almost constant value, but the conductivity gradually decreased. After 67 minutes, the pH was 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. After 2-3 hours, the gel had almost collapsed and re-slurried. After 24 hours, this slurry was filtered, washed with methanol, and further dried at 110 ° C., and X-ray diffraction of the obtained powder was performed. It was a site peak, and when the specific surface area was measured by the BET method, a value of 141 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 were radially aggregated, and spherical or subspherical calcium carbonate having a secondary particle diameter of 0.3 to 1.0 μm was confirmed. FIG. 1 shows the particle structure of calcium carbonate at a magnification of 50,000. The physical properties of the polyester resin molded product obtained by kneading the calcium carbonate are as follows.

[0028]

[Table 1]

Example 2 The calcium carbonate obtained in Example 1 was put in a Henschel mixer, 5 parts of CaCO ₃ ethylene-propylene copolymer (Pluronic) was sprayed, stirred and dried, and then ground with a hammer mill. And pulverized. About this thing,
The results of the kneading test with polyethylene are as follows.

[0030]

[Table 2]

Example 3 The calcium carbonate obtained in Example 1 was placed in a Henschel mixer, sprayed with 5 parts / CaCO ₃ of a phosphoric acid diester, stirred, dried and then pulverized with a hammer mill to give a powder. The results of a kneading test with polypropylene for this product are shown in Table 3.

Comparative Example 1 0.04 μm colloidal calcium carbonate obtained by introducing carbon dioxide gas into a lime milk suspension at a concentration of 5% and 15 ° C. was aged at 80 ° C. for 2 days, and then at first 0. 3 μm cubic calcium carbonate is produced. Concentrate this suspension to 15
After adjusting the concentration to 5%, 5 parts / phosphoric acid diester of CaCO ₃ was added for surface treatment, and then dried, pulverized and pulverized. It was kneaded with polypropylene in the same manner as in Example 3.

The PP test results of Example 3 and Comparative Example 1 are as follows.

[0034]

[Table 3]

Example 4 The calcium carbonate obtained in Example 1 was dispersed in water to prepare 1
A water suspension having a concentration of 5% was prepared and surface-treated with 3 parts / sodium fatty acid of CaCO ₃ , dried and pulverized, and kneaded with polyvinyl chloride.

Comparative Example 2 The 0.3 μm untreated calcium carbonate obtained in Comparative Example 1 was surface-treated with fatty acid soda in the same manner as in Example 4, and the obtained powder was kneaded with polyvinyl chloride. ..

The PVC test results of Example 4 and Comparative Example 2 are as follows.

[0038]

[Table 4]

[0039]

According to the present invention, a highly dispersible calcium carbonate is produced as a filler for plastics,
When used in a plastic molded product, the functionality such as strength is enhanced and the added value is improved.

Further, by subjecting it to a surface treatment as required, it can be effectively used as an additive for rubber, paint, ink, sealant, paper or cosmetics, toothpaste, pharmaceuticals, etc., in addition to plastic applications. It is also useful as a pigment, filler and catalyst carrier.

[Brief description of drawings]

FIG. 1 is a scanning electron micrograph showing a particle structure of calcium carbonate according to the present invention at a magnification of 50,000.

Front Page Continuation (72) Inventor Seiji Asaba 8-10-16 Shimorenjaku, Mitaka City, Tokyo Nittetsu Mining Co., Ltd.

Claims (3)

[Claims] 1. A plastic molded product containing calcium carbonate, which is produced in an ethylene glycol system and is untreated or surface-treated with a treatment agent having a high affinity for plastics. 2. Calcium carbonate is calcium oxide,
At least one of a calcium compound, which is either a calcium hydroxide or a calcium halide, or metal calcium is carbonized in a medium system containing 80% by weight or more of ethylene glycol, and is obtained through an aging step. The plastic molded body according to claim 1. 3. The secondary particle size of calcium carbonate is 0.1 to 10.
BET specific surface area of 20 to 300 m ² / g at 2.0 μm
The plastic molded product according to claim 1, which is in the range.