JP2001089505A - Inorganic dispersant, stabilizer for suspension polymerization, polymer particles, and unsaturated polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic dispersant having high surface activity, easy deagglomeration, and useful as a stabilizer for suspension polymerization. SOLUTION: It is made of calcium carbonate synthesized by adding a particle growth inhibitor, and satisfies the following (a) to (c). (A) 0.002 ≦ dx1 ≦ 0.1 (μm) (b) 0.005 ≦ α ≦ 0.5 (c) 20 ≦ Sw1 ≦ 200 (m ² / g) where dx1: average by electron micrograph Particle size (μm). α: 50% average particle size (μm). Sw1: BET specific surface area (m ² / g)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an inorganic dispersant, a stabilizer for suspension polymerization comprising the same, polymer particles using the dispersant, and an unsaturated polyester resin composition. The present invention relates to an inorganic dispersant which is easily deagglomerated, a stabilizer for suspension polymerization comprising the same, a polymer particle having a uniform and sharp particle size distribution using the dispersant, and an unsaturated polyester resin composition using the particle. . The polymer particles having a uniform and sharp particle size distribution according to the present invention are, in particular, antiblocking agents for LCD spacers and films requiring fine polymer particles, flow viscosity modifiers for paints and inks, matting agents for paints, It is useful for applications such as thermal paper slip imparting agents and cosmetics.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a spherical polymer, a method of suspension polymerization and a method of dissolving a polymer in a solvent and removing the solvent from a suspension dispersed and suspended in water are known. I have. On the other hand, as an inorganic dispersant, the effect of a poorly water-soluble phosphate for suspension polymerization has been known for a long time, and particularly for a hydroxyapatite-based suspension polymerizer, the dispersibility of a polymerizable monomer in an aqueous solution is high. It has been developed to be expensive. The improvement is described in Japanese Patent Publication No. 54-44313,
222103, JP-A-06-220108, JP-A-7-102005 and JP-A-7-102006 are known, and the half-life of sedimentation and the electric conductivity are used as indicators of the improvement. In this index, the longer the sedimentation half-life and the lower the electric conductivity, the more suitable as a dispersant.

[0003] Examples of applications in which poorly water-soluble phosphates for suspension polymerization are applied include, for example, in the polymerization of polystyrene, polymerization of general expanded polystyrene, and three-dimensional polymerization as a low shrinkage agent for unsaturated polyester resin compositions. There is polymerization of polymer fine particles (JP-A-7-82305). Applications of polymer particles include LCD spacers, LCD diffusion plates, film blocking inhibitors, paint / ink flow viscosity modifiers, thermal paper slipperiness imparting agents, and cosmetics applications and many other uses. It is.

[0004] In general suspension polymerization of general-purpose styrene monomers, a dispersant system comprising an organic surfactant such as polyvinyl alcohol and polyvinyl pyrrolidone, or a tribasic calcium phosphate, hydroxyapatite, pyrophosphate or the like. Dispersant systems using a poorly water-soluble inorganic salt and an anionic surfactant such as sodium dodecylbenzenesulfonate, sodium α-olefin sulfonate, sodium salt of lauric sulfate and the like are known. However, when an organic surfactant is used as a dispersant, the dispersant is mixed into the polymer particles, resulting in a decrease in heat stability, deterioration in transparency,
Alternatively, the mechanical strength is lowered, and the COD of the polymerization waste liquid is increased, which is not preferable from the viewpoint of wastewater treatment.

On the other hand, in a dispersion in which an anionic surfactant is used in combination with a poorly water-soluble inorganic salt, high suspension stability can be obtained with a small amount of a poorly water-soluble inorganic salt. Suspension polymerization of the body results in a relatively broad particle size distribution of the resulting polymer particles.

[0006] Polymer particles mainly composed of polystyrene obtained by suspension polymerization are generally formed into various molded articles by extrusion molding or injection molding. However, when polymer particles having a wide particle size distribution are used, a molding machine is used. This causes a problem that the supply of raw materials to the container fluctuates and the defective rate of the molded product increases. In addition, the three-dimensional polymer fine particles as a low-shrinkage agent of the unsaturated polyester have a problem that, in a molded article of the unsaturated polyester, uniform dispersibility, gloss, low shrinkage, and transparency are poor.

[0007] The use of polymer particles mainly composed of polystyrene obtained by suspension polymerization is, for example, the following general use (1) to (3), uniform dispersibility in unsaturated polyester molded articles. There are applications (4) for imparting gloss, low shrinkage, and transparency, and applications (5) for spacers for liquid crystal display panels, and the required particle size of the polymer particles is determined. In addition, an anti-blocking agent for film, a flow viscosity adjusting agent for paints and inks, a slipperiness imparting agent for thermal paper,
And for cosmetics applications, from sub-μm to several 100μ
Polymer particles having a particle size of m are properly used.

(1) Particles having a particle diameter of about 0.4 to 0.7 mm: cups for instant foods and the like (2) Particles having a particle diameter of about 0.7 to 1.8 mm: various packing materials (3) About 1 0.8 to 3.0 mm particle size: building material board (4) Particle size of about 30 to 80 μm: low shrinkage agent of unsaturated polyester (5) 3 to 50 μm particle size: liquid crystal display panel Spacer

The polymer particles are roughly classified into the above (1) to
(3) the relatively large particles in mm units and the above (4) to
The particles are divided into fine particles of sub-μm to several tens μm of (5), and the required particle diameter varies depending on the use of the spherical polymer particles as described above. That is, the physical properties for use cannot be satisfied unless the content is within a certain particle size. Therefore, when the particle size distribution of the polymer particles is wide, the yield is greatly reduced.

On the other hand, as for the inorganic dispersant, an inorganic dispersant which can be adapted to the required physical properties of the spherical polymer is required.
As the inorganic polymerization dispersant represented by the inorganic dispersant,
Hydroxyapatite has been used in the past, and improvements have been made. It has been conventionally considered that the finer the hydroxyapatite stabilizing effect, the greater the surface active energy, which is preferable. However, the particles in the slurry obtained from the process of producing apatite usually have a fine particle size, and thus easily aggregate, which results in a non-uniform particle size of the polymer. That is, it is important that the apatite particles are fine and that the particles have good dispersibility. In order to improve these, a method of subjecting an apatite slurry to strong shear dispersion treatment to perform deagglomeration is generally used, but it is difficult to uniformly disperse agglomerates of fine crystals of apatite.
As described above, the study of the inorganic dispersant mainly focuses on the calcium phosphate-based compound containing hydroxyapatite, and the study of calcium carbonate has hardly been conducted.

In recent years, the size of polymer particles, such as polymer particles for spacers of touch panels, has been reduced, and this method generates fine particles and increases the amount of inorganic dispersants used. Acid washing after the polymerization process,
The washing step becomes complicated, and an inorganic dispersant which cannot be removed by acid washing remains, which may adversely affect the use.
Furthermore, in view of recent environmental problems, there is a demand for an inorganic dispersant capable of obtaining a sufficient effect by adding a small amount thereof.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has solved the above-mentioned problems in the prior art.
In particular, the present invention provides an inorganic dispersant useful for obtaining a desired particle size and dispersibility when polymer particles are obtained by a suspension polymerization method or a dissolved polymer suspension method.

[0013]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have disclosed in Japanese Patent Application No. 10-96814 that the particle size distribution is improved by improving the particle size and dispersibility of a calcium carbonate inorganic dispersant. It has been disclosed that spherical polymer particles which are sharp and can improve the yield can be produced, but they are used for touch panel spacers, film blocking inhibitors, paint / ink flow viscosity modifiers, and thermal paper slipperiness. For use in imparting agents and cosmetics, polymer particles are desired to be finer and sharper, and satisfactory ones have not yet been obtained. Thus, the present inventors have further studied as a result, while suppressing the particle growth of calcium carbonate,
An excellent inorganic dispersant can be provided by defining the particle dispersibility and particle size of calcium carbonate, and by using this inorganic dispersant, a polymer particle having a desired particle size, a narrow particle size distribution, and excellent quality. The present inventors have found that the present invention can be obtained. According to the present invention, calcium carbonate can be used even in a field where it could only be used with hydroxyapatite until now, the function as an inorganic dispersant has been improved, and polymer particles having improved quality have been obtained. And the amount of the inorganic dispersant used can be reduced, and labor can be saved in the subsequent acid washing step, and it is possible to provide an inorganic dispersant and polymer particles that are advantageous in terms of cost. .

A first aspect of the present invention is a composition synthesized by adding a particle growth inhibitor of calcium carbonate, and represented by the following formulas (a) to (c).
An inorganic dispersant comprising calcium carbonate satisfying the following. (A) 0.002 ≦ dx1 ≦ 0.1 (μm) (b) 0.005 ≦ α ≦ 0.5 (c) 20 ≦ Sw1 ≦ 200 (m ² / g) where dx1: measured by electron micrograph Average particle size (μm) of the obtained particles. α: Particle size of d50: 50% average particle size (μm) of particles measured by Shimadzu type particle size distribution meter CP-4L. Sw1: BET specific surface area by nitrogen adsorption method (m ² / g)

The second aspect of the present invention further includes an inorganic dispersant satisfying the following formulas (d) and (e). (D) β ≦ 25 (% by weight) (e) γ ≦ 40 (% by weight) β: Integrated weight% of 1 μ or more measured by Shimadzu type particle size distribution analyzer CP-4L γ: By Shimadzu type particle size distribution analyzer CP-4L 0.5 measured
Integrated weight% of μ or more

A third aspect of the present invention is directed to a suspension polymerization stabilizer comprising the above inorganic dispersant.

The fourth aspect of the present invention includes polymer particles obtained by suspension-polymerizing a vinyl monomer which can be subjected to suspension polymerization in a mixed system of a polymerization initiator, a dispersion medium and the above-mentioned inorganic dispersant.

A fifth aspect of the present invention is to dissolve the polymer in a solvent using the above-mentioned inorganic dispersant as a stabilizer, and remove the solvent from the suspension dispersed and suspended in water to obtain polymer particles. And

A sixth aspect of the present invention is directed to an unsaturated polyester resin composition containing the polymer particles of the fourth or fifth aspect as a low shrinkage agent.

[0020]

Important features of the inorganic dispersant of the present invention are the particle size, dispersibility, and surface activity of the calcium carbonate and the frequency of coarse particles. Ordinary apatite particles are, for example, very fine particles having an oval particle size of about 0.1 μm. However, since they have strong surface activity, they agglomerate violently, and are actually effective as secondary particles. In addition, it is difficult to disperse the secondary particles even when deagglomeration is performed, and the particles have very fine particles and large secondary particles, and have a very wide particle size distribution. I could not be satisfied.

The calcium carbonate inorganic dispersant of the present invention having suppressed particle growth is easy to deagglomerate,
Since it is easy to increase the surface activity, the resulting polymer dispersant is superior to ordinary apatite particles as a result. That is, it has become possible to simultaneously exert the opposing effects of surface activity and dispersibility, which are characteristics of the inorganic dispersant.

Although calcium carbonate is hardly soluble in water, a slight amount of dissolution causes particle growth. Particularly, during the polymerization, the reaction temperature is high, so that the particle growth may occur. However, by adding an additive that suppresses the particle growth, the effect of the stable inorganic dispersant can be exhibited.

The present invention has been completed on the basis of the above-mentioned findings, and its object is to always produce polymer particles having a sharp particle size distribution.・ Inorganic material consisting of calcium carbonate with good dispersibility, which can provide polymer particles for applications requiring fine particles such as ink flow viscosity modifiers, thermal paper slipperiness imparting agents, and cosmetics. It is to provide a dispersant.

Calcium carbonate constituting the inorganic dispersant of the present invention can be roughly classified into light calcium carbonate and colloidal calcium carbonate, but it is easy to adjust the primary particle diameter and has good dispersibility. Is preferred. In addition, calcium carbonate must be synthesized by adding a particle growth inhibitor, and must satisfy the above-described formulas (a) to (c).

That is, the formula (a) is the primary particle size of the inorganic dispersant of the present invention, and the primary particle size dx1 is 0.002 ≦
dx1 ≦ 0.1 (μm), preferably 0.005 ≦ dx
1 ≦ 0.07 (μm), more preferably 0.01 ≦ dx
1 ≦ 0.05 (μm). Primary particle dx1 is 0.0
When the particle size is smaller than 02 μm, deagglomeration cannot be performed, the effect as a dispersant decreases, and the particle size distribution of the polymer particles becomes uneven. Further, the primary particles dx1 are 0.1 μm.
If it is larger than m, the activity of the dispersant decreases, and the polymer particles become uneven and adhere to the wall surface. Further, when the amount of the inorganic dispersant is increased to further exert the effect of the inorganic dispersant, the inorganic dispersant may not be removed in the acid washing step in some cases.

Next, the formula (b) is the secondary particle size of the inorganic dispersant of the present invention, and shows the behavior of the dispersant in a water slurry. As an index of a normal hydroxyapatite inorganic dispersant, the sedimentation half-life is used.Since the sedimentation half-life is obscured by visual judgment and turbidity judgment, a numerically clear index of particle size distribution is used. Incorporated. The secondary particle diameter α is 0.005 ≦ α ≦ 0.5 (μ
m), preferably 0.01 ≦ α ≦ 0.3 (μm), more preferably 0.02 ≦ α ≦ 0.2 (μm). When α is larger than 0.5 μm, the activity of the dispersant decreases,
The particle size of the polymer particles becomes uneven, and the polymer particles adhere to the polymer particles. When α is smaller than 0.005 μm, deagglomeration is costly and the viscosity may increase during polymerization.

Next, the formula (c) is a BET specific surface area of the inorganic dispersant of the present invention by a nitrogen adsorption method, and Sw1 is 20
≦ Sw1 ≦ 200 (m ² / g), preferably 50 ≦ Sw1
≦ 150 (m ² / g), more preferably 80 ≦ Sw
1 ≦ 120 (m ² / g). When Sw1 is less than 20 m ² / g, the particle size of the polymer particles becomes non-uniform,
The polymer particles adhere to the wall. In addition, Sw1 is 200 m ²
If it is larger than / g, deagglomeration is costly and the viscosity may increase during polymerization.

Examples of the calcium carbonate particle growth inhibitor in the present invention include a Ca chelating agent, a phosphorus-containing substance, and a sulfuric acid compound. When producing the calcium carbonate constituting the inorganic dispersant, these particle growth inhibitors are preferably added at the stage of an aqueous suspension of calcium hydroxide (milk of lime) or primary carbonated lime.
More preferably, it is added at the stage of lime milk. By suppressing the crystal growth of calcium carbonate with a particle growth inhibitor, finer calcium carbonate can be obtained,
Also, particle growth is suppressed in the calcium carbonate dispersion step, and a fine inorganic dispersant having better dispersibility can be obtained.

Any Ca chelating agent may be used as long as it can chelate Ca ions. For example, citric acid,
Hydroxycarboxylic acids such as oxalic acid and malic acid and their alkali salts, alkaline earth metal salts and ammonium salts; polyhydroxycarboxylic acids such as gluconic acid and tartaric acid and their alkali metal salts and alkaline earth metal salts; iminodiacetic acid;
Aminocarboxylic acids such as ethylenediaminetetraacetic acid and nitrilotriacetic acid and their alkali metal salts, alkaline earth metal salts and ammonium salts; amino acids such as glutamic acid and aspartic acid and their metal salts, alkaline earth metal salts and ammonium salts; acetylacetone And ketones such as methyl acetoacetate and allyl acetoacetate.

The phosphorus-containing compound may be any compound that reacts with a calcium carbonate inorganic dispersant such as ortho or condensed phosphoric acid and a sodium salt of phosphoric acid such as Na salt, Ka salt and NH ₄ salt. Orthophosphoric acid such as sodium phosphate, potassium phosphate, ammonium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, ammonium hydrogen phosphate and salts thereof; hexametaphosphate, pyrophosphate, sodium hexametaphosphate, potassium hexametaphosphate, hexametaphosphate Examples include ammonium, sodium pyrophosphate, potassium pyrophosphate, and ammonium pyrophosphate.

As the sulfuric acid compound, sulfuric acid and N
alkali metal salts such as a and K, ammonium salts, Mg, C
and alkaline earth metal salts such as a, and transition metal salts such as Al, Zn, and Fe.

Among these, a Ca chelating agent is particularly preferred, and a citric acid chelating agent is particularly preferred. Ca
It is considered that by adding a chelating agent, elution and aggregation of calcium carbonate particles can be prevented during suspension polymerization or in a method of removing a solvent from a suspension in which a polymer is suspended.

The above-mentioned Ca chelating agent, phosphorus-containing compound,
The sulfate compounds may be used alone or in combination of two or more. The addition amount of these particle growth inhibitors is 0.01 to 15% by weight, preferably 0.05 to 10% by weight, more preferably 0.2 to 3% by weight based on 100% by weight of the inorganic dispersant of the present invention.
% By weight. When the addition amount of the particle growth inhibitor to the inorganic dispersant is less than 0.01% by weight, the particle size of the polymer particles becomes non-uniform and the polymer particles may adhere. On the other hand, if the content is more than 15% by weight, the effect corresponding to the increase in the added amount is not so much recognized, which is rather uneconomical.

The inorganic dispersant of the present invention preferably has a low frequency of coarse particles, and the integrated weight% is 1 μm or more as measured by Shimadzu type particle size distribution meter CP-4L. β is preferably 25% by weight or less, more preferably 10% by weight or less, and still more preferably 5% by weight.
It is as follows. When β is more than 25% by weight,
When it is used for polymer particles of fine particles of up to several tens of μm, the effect of uniformly covering the polymer particles is reduced, a composite with the polymer particles is formed, and it cannot be removed even by acid washing, and the sub-μm
In some cases, the physical properties of polymer particles of fine particles having a size of from 10 μm to several tens μm may be reduced. From the viewpoint of the effect of the inorganic dispersant, the content is preferably 5% by weight or less.

Similarly, in the integrated weight%, γ, which is an integrated weight% of 0.5 μ or more measured by Shimadzu type particle size distribution meter CP-4L, is preferably 40% by weight or less, more preferably 20% by weight or less. , More preferably 10% by weight or less. If it is more than 40% by weight,
When used for fine polymer particles of up to several tens of μm, the effect of uniformly covering the polymer particles is reduced, a composite with the polymer particles is formed, and the polymer particles cannot be removed even by acid washing. May cause a decrease. From the viewpoint of the effect of the inorganic dispersant, the content is preferably 10% by weight or less.

The inorganic dispersant of the present invention is preferably deagglomerated. It is preferable to deagglomerate calcium carbonate obtained from calcium hydroxide and carbon dioxide by aging, or to deagglomerate by a method of repeating dehydration and washing while removing alkali by a powerful shear disperser, ultrasonic dispersion, and washing with water. . Examples of the powerful shear disperser include dispersers such as a colloid mill, a homogenizer, a homogenizer, and a media mill. The method of deagglomeration includes primary grinding (a method of deagglomerating calcium carbonate obtained from calcium hydroxide and carbon dioxide) and secondary grinding (dehydration of calcium carbonate obtained from calcium hydroxide and carbon dioxide), Deagglomeration using the above surfactant). Preferably, the primary pulverization and the secondary pulverization are used in combination. In the primary pulverization, the water slurry solids concentration of the calcium carbonate inorganic dispersant is preferably 5% by weight or more, more preferably 10% by weight or more. It is preferable to increase the pulverization efficiency so as to obtain a predetermined particle size, or to carry out treatment with a powerful shear disperser many times. After the primary pulverization, it is preferable to remove the alkali by pulverization with carbon dioxide gas.

Examples of the organic surfactant include the following surfactants, and these can be used alone or in combination of two or more. One type is a group consisting of a polymer of a monomer having a vinyl group and a partially or completely neutralized product thereof with an alkali metal salt, ammonium, and an amine. Acid, α, β unsaturated dicarboxylic acid, alkyl methacrylate, (meth) acryl ether having an alkoxy group, (meth) acrylate having a cyclohexyl group, α, β monoethylenically unsaturated hydroxy ester, polyalkylene glycol Mono (meth) acrylate, vinyl ester, vinyl aromatic,
Examples include unsaturated nitriles, unsaturated dicarboxylic esters, vinyl ethers, conjugated dienes, chain olefins, cyclic olefins, and sulfo group-containing monomers.

Other types include alkyl ether sulfuric acid, alkyl ether phosphoric acid, alkyl aryl ether sulfuric acid, alkyl aryl ether phosphoric acid, alkyl sulfate ester, alkyl phosphate ester, alkyl aryl sulfate, alkyl aryl phosphoric acid, alkyl amide sulfate. , Alkylsulfonic acid, alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, sulfosuccinic acid,
Sulfosuccinate, α-olefinsulfonic acid,
N-acylsulfonic acid, N-acylamino acid, alkyl ether carboxylic acid, acylated peptide, aliphatic amine, aliphatic quaternary amine, aromatic quaternary ammonium, betaine, aminocarboxylic acid, imidazoline derivative, alkyl ether, alkyl Examples include allyl ether, alkyl ester, alkylamine, sorbitan derivative, polycyclic phenyl ether, fatty acid ester, fluoroalkyl carboxylic acid, perfluoroalkyl carboxylic acid, perfluoroalkyl sulfonic acid, acetylene alcohol, acetylene glycol and the like. Further, water-soluble polymers such as gum arabic, starch, gelatin, casein, chitin, hydroxycellulose, carboxymethylcellulose, and polyvinyl alcohol can also be used. The amount of the organic surfactant used is 100 calcium carbonate.
A suitable amount is 0.01 to 30 parts by weight based on parts by weight.
If the amount is less than 0.01 part by weight, a sufficient surface treatment effect cannot be obtained. On the other hand, if the amount exceeds 30 parts by weight, the excess adsorption rate decreases, and further effects cannot be expected, which is often uneconomical. . By using the above-mentioned organic surfactant, deagglomeration of the inorganic dispersant can be facilitated, reaggregation (reagglomerate) can be suppressed, and dispersion of the polymer particles can be improved.

In the production of the precipitated calcium carbonate used for the inorganic dispersant of the present invention, for example, a gas containing carbon dioxide (hereinafter, referred to as carbon dioxide) is passed through an aqueous suspension of calcium hydroxide (hereinafter, referred to as lime milk). A known method such as a method of spraying a mixture of lime milk or calcium hydroxide and precipitated calcium carbonate in carbon dioxide gas may be used.
Preferably, the calcium carbonate particles are dispersed as much as possible. For example, as a method, the carbonation reaction is stopped at a pH of 7.5 to 10.0 of the reaction system, the mixture is stirred, and calcium carbonate is added. Elution of residual alkali in the system, and addition or conduction of lime milk and carbon dioxide into the system as necessary to control the pH of the system at 9.0 to 12.0 for 5 hours or more, or during carbonation Alternatively, a method of passing precipitated calcium carbonate after completion of carbonation through a powerful shearing machine may be used. Since the calcium carbonate inorganic dispersant is produced in a water slurry, it can be used as it is. Further, an inorganic dispersant powdered by dehydration, drying and pulverization by a conventional method can also be used.

The third aspect of the present invention relates to a suspension polymerization stabilizer comprising the above-mentioned inorganic dispersant of the present invention, and the fourth aspect of the present invention relates to a vinyl monomer capable of undergoing suspension polymerization with the above-mentioned inorganic dispersant and a polymerization initiator. And polymer particles suspension-polymerized in a mixed system of an agent and a dispersion medium. That is, when the inorganic dispersant of the present invention is used, polymer particles having a uniform and sharp particle size distribution can be generated, and the particle size of the polymer can be controlled.

In the suspension polymerization method, the above inorganic dispersant can be used as a polymerization stabilizer without changing the conventional suspension polymerization operation. Examples of the vinyl monomer include one or more suspension-polymerizable monomers selected from substituted or unsubstituted styrene, (meth) acrylates, acrylonitrile, vinyl esters, olefins, and the like. But there is no particular limitation. If necessary, other organic stabilizers, for example, a water-soluble polymer compound such as polyvinyl alcohol, CMC, and gelatin, a surfactant such as sodium dodecylbenzenesulfonate, pH, etc.
An adjusting agent, a specific gravity adjusting agent or a viscosity adjusting agent, a coloring agent and the like may be appropriately used in combination.

The amount of the inorganic dispersant used for suspension polymerization in the present invention varies depending on its physical properties and the conditions of suspension polymerization.
It is used in the range of 〜10.0% by weight, preferably 0.15 to 5.0% by weight, and it is possible to charge it all at once before the start of suspension polymerization or to divide it in parts depending on the polymerization rate. Moreover, it does not interfere at all even if it is used together with a commercially available hydroxyapatite inorganic dispersant.

A fifth aspect of the present invention is to use the inorganic dispersant of the present invention as a stabilizer, dissolve a polymer in a solvent, and disperse the polymer in water.
The present invention relates to polymer particles obtained by removing a solvent from a suspended suspension.

Specifically, after mixing an aqueous solution containing a surfactant and an inorganic dispersant with a mother liquor containing a polymer and an organic solvent, the organic solvent and water are removed to produce polymer particles. Examples of the polymer particles thus obtained include a polyester resin and a vinyl polymer obtained by polymerizing a polymerizable vinyl polymer.

The polyester resin can be produced by a known method using an alcohol component and an acid component as raw materials.
As a vinyl polymer, styrene is used in an amount of 50% by weight or more based on all monomers in view of the balance of various properties, and any one of an alkyl acrylate and an alkyl methacrylate or a mixture thereof is left in a total amount. The polymer obtained by using 50% by weight or more based on the monomer is preferable.

The organic solvent is not particularly limited as long as it can dissolve the polymer.
Hydrocarbons (toluene, xylene, hexane, etc.) include halogenated hydrocarbons, alcohols or ethers, esters, ketones, and acetal. If necessary, one or more of a surfactant such as sodium dodecylbenzenesulfonate, a magnetic or magnetizable material, an anti-offset agent, a positive or negative charge control agent, and silica powder may be appropriately used. There is no harm in using them together.

The amount of the inorganic dispersant of the present invention varies depending on its physical properties and production conditions. In many cases, the amount of the inorganic dispersant of the present invention is 0.1 to 100% by weight relative to the resin. Is preferably used in the range of 0.15 to 50% by weight. It is also possible to charge them all at once before starting solvent removal, or to charge them separately according to the solvent removal rate.

A sixth aspect of the present invention is that a polymer particle suspension-polymerized in a mixture of the inorganic dispersant of the present invention, a suspension-polymerizable vinyl monomer, a polymerization initiator, and a dispersion medium is used as a low shrinkage agent. It relates to an unsaturated polyester resin composition characterized by containing. It is preferable to use three-dimensional polymer particles produced by adding a crosslinking agent such as divinylbenzene. Further, as a component of the unsaturated polyester resin composition, polymerization of styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, divinylbenzene, lower alkyl esters of acrylic acid or methacrylic acid, diallyl phthalate, diallyl isophthalate, etc. The hydrophilic monomer can be used in a commonly used amount. In addition, if necessary, fillers such as calcium carbonate and alumina, thickeners such as magnesium oxide, magnesium hydroxide and calcium oxide, curing catalysts such as various organic peroxides, coloring agents such as various dyes and pigments, etc. Can be used. The resulting polyester resin composition was SM
It is used for various molded products by C, BMC, TMC, RIM, etc. Suspension polymerization using the inorganic dispersant of the present invention has a sharp particle size distribution of 30 to 80 μm.
It is possible to obtain a molded article having excellent low shrinkage, uniform dispersibility, gloss, and transparency by blending the polymer fine particles with the unsaturated polyester. It is possible.

[0049]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Lime milk having a specific gravity of 1.07 was adjusted to 13 ° C., and 10% by weight of triammonium citrate was added to calcium hydroxide in an amount of 25%.
% By weight, and 1 kg of calcium hydroxide is added to the slurry.
30 liters / min of carbon dioxide (27% of which is C
O ₂ ) was conducted to carry out a carbonation reaction. When the pH of the system reached 8.0, the carbonation reaction was stopped, and then the pH was raised to 10.
When the value reached 0, the aqueous calcium carbonate suspension was wet-pulverized using a wet pulverizer (Dynomill) as a primary pulverization to obtain an aqueous calcium carbonate suspension. Since the pH of the obtained calcium carbonate is as high as 11.0, the pH is again adjusted with carbon dioxide gas.
Was set to 7.0, and the same operation was repeated for a total of 3 passes to obtain an inorganic dispersant a. Average particle size, BET, measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant
Table 1 shows the specific surface area and the d50 particle size measured with a Shimadzu type particle size distribution meter CP-4L.

Example 2 An inorganic dispersant b was obtained in the same manner as in Example 1 except that the amount of citric acid was changed to 50% by weight. Average particle size, BET specific surface area, Shimadzu type particle size distribution meter CP measured from electron micrographs of calcium carbonate constituting the inorganic dispersant
Table 1 shows the d50 particle size measured by -4L.

Example 3 An inorganic dispersant c was obtained in the same manner as in Example 1 except that 30% by weight of 10% by weight of phosphoric acid was added instead of citric acid. Average particle diameter, BET specific surface area, d50 measured by Shimadzu type particle size distribution meter CP-4L measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant.
Table 1 shows the particle size.

Example 4 An inorganic dispersant d was prepared in the same manner as in Example 1 except that 30% by weight of 10% by weight sulfuric acid was added instead of citric acid.
I got The average particle diameter, BET specific surface area, measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant,
Table 1 shows the d50 particle size measured with a Shimadzu type particle size distribution meter CP-4L.

Example 5 Lime milk having a specific gravity of 1.06 was adjusted to 13 ° C., and carbon dioxide gas (of which 27% was CO ₂ ) was passed through the slurry at a rate of 30 liters / min per kg of calcium hydroxide to form a gel. After preparation, 10% by weight of triammonium citrate was added to calcium hydroxide at 30% by weight to carry out a carbonation reaction. When the pH of the system reached 8.0, the carbonation reaction was stopped, and then the pH was lowered. When it reached 10.0, the calcium carbonate aqueous suspension was wet-pulverized using a wet pulverizer (Dynomill) as a primary pulverization to obtain a calcium carbonate aqueous suspension. Since the pH of the obtained calcium carbonate is as high as 11.0, the obtained calcium carbonate aqueous suspension was again adjusted to pH 7.0 with carbon dioxide gas, and the same operation was repeated twice to make a total of 3 passes to obtain an inorganic dispersant. e was obtained. Average particle size, BET, measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant
Table 1 shows the specific surface area and the d50 particle size measured with a Shimadzu type particle size distribution meter CP-4L.

Example 6 Lime milk having a specific gravity of 1.07 was adjusted to 13 ° C., and 10% by weight of triammonium citrate was added to calcium hydroxide in an amount of 25%.
% By weight, and 1 kg of calcium hydroxide is added to the slurry.
30 liters / min of carbon dioxide (27% of which is C
O ₂ ) was conducted to carry out a carbonation reaction. When the pH of the system reached 8.0, the carbonation reaction was stopped, and then the pH was raised to 10.
When the value reached 0, the aqueous calcium carbonate suspension was wet-pulverized using a wet pulverizer (Dynomill) as a primary pulverization to obtain an aqueous calcium carbonate suspension. Since the pH of the obtained calcium carbonate is as high as 11.0, the pH is again adjusted with carbon dioxide gas.
Was adjusted to 7.0, and the same operation was repeated three times on the obtained aqueous calcium carbonate suspension to obtain inorganic dispersant f in four passes in total. Table 1 shows the average particle diameter, BET specific surface area, and d50 particle diameter of the calcium carbonate constituting the inorganic dispersant, as measured from an electron micrograph, measured with a Shimadzu type particle size distribution meter CP-4L.

Example 7 Lime milk having a specific gravity of 1.07 was adjusted to 13 ° C., and 10% by weight of triammonium citrate was added to calcium hydroxide in an amount of 25%.
% By weight, and 1 kg of calcium hydroxide is added to the slurry.
30 liters / min of carbon dioxide (27% of which is C
O ₂ ) was conducted to carry out a carbonation reaction. When the pH of the system reached 8.0, the carbonation reaction was stopped, and then the pH was raised to 10.
When it reached 0, the aqueous calcium carbonate suspension was wet-pulverized using a wet pulverizer (Dynomill) to obtain an aqueous calcium carbonate suspension. The pH of the obtained calcium carbonate is 1
Since the pH was as high as 1.0, the obtained calcium carbonate aqueous suspension was again adjusted to pH 7.0 with carbon dioxide gas. The same operation was repeated four times to obtain an inorganic dispersant g in five passes in total. Average particle size, BET specific surface area, Shimadzu type particle size distribution meter C measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant
Table 1 shows the d50 particle size measured by P-4L.

Comparative Example 1 A lime milk having a specific gravity of 1.07 was adjusted to 15 ° C., and carbon dioxide gas (30 liters / min.
% Through CO ₂ ) to carry out a carbonation reaction. When the pH of the system reaches 8.0, the carbonation reaction is stopped and the pH
The mixture was stirred at 10.2 for 15 hours. When the viscosity of the system reached 2300 cp, carbon dioxide gas was passed again to raise the pH of the system to 6.8.
To obtain an inorganic dispersant h. Average particle diameter measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant,
Table 1 shows the BET specific surface area and the d50 particle diameter measured with a Shimadzu type particle size distribution meter CP-4L.

Comparative Example 2 Lime milk having a specific gravity of 1.07 was adjusted to 13 ° C., and 10% by weight of triammonium citrate was added to calcium hydroxide in an amount of 25%.
% By weight, and 1 kg of calcium hydroxide is added to the slurry.
30 liters / min of carbon dioxide (27% of which is C
O ₂ ) was conducted to carry out a carbonation reaction, and when the pH of the system reached 7.0, the carbonation reaction was stopped to obtain an inorganic dispersant i. Table 1 shows the average particle diameter, BET specific surface area, and d50 particle diameter of the calcium carbonate constituting the inorganic dispersant, as measured from an electron micrograph, measured with a Shimadzu type particle size distribution meter CP-4L.

Comparative Example 3 Lime milk having a specific gravity of 1.07 was adjusted to 15 ° C., and carbon dioxide gas (30 liters / min.
% Through CO ₂ ) to carry out the carbonation reaction. When the pH of the system reaches 8.0, the carbonation reaction is stopped, and then the pH is lowered.
Reached 10.0, the aqueous calcium carbonate suspension was wet-pulverized using a wet pulverizer (Dynomill) to obtain an inorganic dispersant h. Average particle size, BET specific surface area, d5 measured by Shimadzu type particle size distribution meter CP-4L measured from an electron micrograph of calcium carbonate constituting the inorganic dispersant.
Table 1 shows the 0 particle size.

Comparative Example 4 A commercially available hydroxyapatite inorganic dispersant (solid content: 10% by weight) k was prepared.

The particle size distribution of the Shimadzu CP-4L was measured by adding the slurry to an aqueous solution of 0.2% by weight sodium hexametaphosphate, dispersing the mixture for 1 minute with ultrasonic waves, adjusting the concentration to a predetermined concentration, A measurement was made.

[0062]

[Table 1]

Examples 8 to 14 and Comparative Examples 5 to 8 Suspension polymerization of styrene was carried out using the inorganic dispersant having a solid content concentration of 10% by weight of a to k shown in Table 1 with the following composition.
The following mixture was placed in a stainless steel autoclave with a stirring blade, and the inside of the autoclave was replaced with nitrogen gas. Subsequently, the reaction was continued at 90 ° C. for 10 hours while stirring at a stirring speed of 350 rpm to perform suspension polymerization. Next, the polymer was dehydrated by a centrifugal separator by a conventional method, and the inorganic dispersant was dissolved with hydrochloric acid, washed with water and dried to obtain styrene polymer particles. Table 2 shows the results. Styrene monomer 100 parts by weight Stabilizer (inorganic dispersant slurry) 0.15 parts by weight (in terms of solid content) Sodium dodecylbenzenesulfonate 0.01 part by weight Benzoyl peroxide 0.2 part by weight Water 100 parts by weight

The average particle size of the polystyrene polymer particles (D
50) and the particle size distribution / yield (peak 3 sieve) are shown in Table 2. Peak 3 sieve: JIS standard sieve opening 2.36 mm
(7.5 mesh), aperture 2.00 mm (8.6 mesh), aperture 1.70 mm (10 mesh), aperture 1.40 mm (12 mesh), aperture 1.18 mm
(14 mesh), aperture 1.18 mm (14 mesh), aperture 1.00 mm (16 mesh), aperture 0.85 mm (18 mesh), aperture 0.71 mm
(22 mesh), aperture 0.60 mm (26 mesh), aperture 0.50 mm (30 mesh), aperture 0.425 mm (36 mesh), aperture 0.355 m
m (42 mesh), mesh size 0.300 mm (50 mesh), mesh size 0.250 mm (60 mesh), mesh size 0.121 mm (70 mesh), mesh size 0.18 m
m (83 mesh), and the particle size (median diameter) at which the cumulative weight becomes 50% based on the cumulative particle size distribution curve is D
50, which indicates the ratio of the particle size distribution in the range of three sieves having a large distribution ratio from the range to which the particle size of D50 belongs.

[0065]

[Table 2]

Examples 15 to 21 and Comparative Examples 9 to 12 As shown in Table 3, a three-dimensional polymer was prepared by the following method using inorganic dispersants a to k having a solid content of 10% by weight as suspension stabilizers. Fine particles were produced. 100 parts by weight of styrene, 0.4 parts by weight of divinylbenzene, 0.6 parts by weight of benzoyl peroxide, 140 parts by weight of water, 20 parts by weight of an inorganic dispersant of 10% by weight of a to k (2.0 parts by weight of solid content) And a three-dimensional polymer fine particle component composed of 1 part by weight of an aqueous solution of 1% by weight of sodium dodecylbenzenesulfonate were mixed with TK homomixer H
V-Sv type equipped with inner diameter 600mm, liquid level height 650
After charging 150 liters (150 kg) into a cylindrical container having a diameter of 150 mm, performing high-speed shearing and stirring at 3300 to 3500 rpm for 15 minutes, and then charging the reaction vessel, the temperature of the reaction vessel was set to 8%.
The temperature was raised to 0 ° C., and polymerization was allowed to proceed for 10 hours, followed by cooling, dehydration and drying to obtain three-dimensional polymer fine particles.

The three-dimensional polymer fine particles were evaluated by the following methods, and the evaluation results are shown in Table 3. Measurement method of particle size distribution of polymer fine particles: Coulter counter (ZM type manufactured by Nikkaki Co., Ltd.) was used. Eyton manufactured by Nikkaki Co., Ltd. was used as the electrolyte. The particle size distribution was measured according to the manual. Yield: The production rate of polymer fine particles having a particle diameter of 30 to 80 μm. Attachment of polymer particles to container wall: Observed visually.

[0068]

[Table 3]

Examples 22 to 28 and Comparative Examples 13 to 17 The three-dimensional polymer particles synthesized in Table 3 and polyethylene (trade name: FLOWSEN UF-20: manufactured by Sumitomo Seika Co., Ltd.) were used as low shrinkage agents. , An unsaturated polyester resin composition was produced by the method described above, and a BCM molded product was obtained using the composition, and the shrinkage ratio, uneven coloring and gloss, and transparency were evaluated. Table 4 shows the evaluation results. (1) Production of unsaturated polyester resin composition Unsaturated polyester resin (Polyset PS-9126-2, maleic acid, terephthalic acid,
Mixture of unsaturated polyester resin and styrene monomer using propylene glycol as raw materials, 100 parts by weight of Hitachi Chemical Co., Ltd.), 1.5 parts by weight of curing agent (Perbutyl Z, manufactured by NOF Corporation), filler ( Heidi Light H32
0, manufactured by Showa Denko KK), 200 parts by weight, 0.3 part by weight of thickener (magnesium oxide), and 15 parts by weight of the three-dimensional polymer fine particles shown in Table 3 were sufficiently dispersed until uniform and unsaturated. A polyester resin composition was obtained. (2) Production of BMC molded product 10 parts by weight of a reinforcing agent (glass fiber, manufactured by Nitto Boseki Co., Ltd.) was mixed with 100 parts by weight of the polyester resin, and kneaded well with a kneader for 10 minutes to prepare a compound.
Next, in order to prevent scattering of styrene, it was packed with a polyethylene terephthalate film, and the compound was aged at 40 ° C. for 20 hours. 7 aged compounds
100 g is placed in a mold having a size of 220 × 220 (mm), a molding temperature of 140 ° C., a molding pressure of 100 kg / cm ² ,
A 6 mm-thick BMC molded product was manufactured under a molding time of 9 minutes. (3) Evaluation of Molded Product Shrinkage: Mold length 220 mm of molded product of BMC obtained
Was measured and evaluated according to the following criteria. Shrinkage (%) = [(220-measured length of BMC molded product)
/ 220] × 100 Coloring and uneven gloss: The obtained molded article was visually judged for coloring and uneven gloss. Transparency: Using a turbidimeter manufactured by Nippon Denshoku Industries Co., Ltd., the transmittance was 100% when there was no sample, and the transmittance was 0% when the sample portion was shielded. After making this correction, B
The MC molded product was put in the sample part, and the transmittance of the molded product was measured.

[0070]

[Table 4]

[0071]

As described above, the inorganic dispersant of the present invention comprises:
Polymer particles having high surface activity, easy deagglomeration and, for example, having a uniform and sharp particle size distribution when used as a stabilizer for suspension polymerization can be provided.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hidehiko Nishioka 1455 Nishioka, Uozumi-cho, Akashi-shi, Hyogo F-term (reference) in Maruo Carsium Co., Ltd. 4J002 BB002 BC032 BF012 BG032 BG102 CF211 FD202 GB00 GD00 GS00 4J011 JA04 JA12 JA18 JB26

Claims (7)

[Claims] 1. An inorganic dispersant which is synthesized by adding a particle growth inhibitor of calcium carbonate and comprises calcium carbonate satisfying the following formulas (a) to (c). (A) 0.002 ≦ dx1 ≦ 0.1 (μm) (b) 0.005 ≦ α ≦ 0.5 (c) 20 ≦ Sw1 ≦ 200 (m ² / g) where dx1: measured by electron micrograph Average particle size (μm) of the obtained particles. α: Particle size of d50: 50% average particle size (μm) of particles measured by Shimadzu type particle size distribution meter CP-4L. Sw1: BET specific surface area by nitrogen adsorption method (m ² / g) 2. The method according to claim 1, wherein the calcium carbonate further comprises the following formula (d):
The inorganic dispersant according to claim 1, which satisfies (e). (D) β ≦ 25 (% by weight) (e) γ ≦ 40 (% by weight) β: Integrated weight% of 1 μ or more measured by Shimadzu type particle size distribution analyzer CP-4L γ: By Shimadzu type particle size distribution analyzer CP-4L 0.5 measured
Integrated weight% of μ or more 3. The calcium carbonate is obtained by adding a calcium carbonate particle growth inhibitor to an aqueous suspension of calcium hydroxide or an aqueous suspension of primary carbonated calcium hydroxide. The inorganic dispersant according to claim 1, wherein calcium carbonate is subjected to a dispersion treatment. 4. A stabilizer for suspension polymerization comprising the inorganic dispersant according to claim 1. 5. A suspension polymerization of a vinyl monomer which can be suspension-polymerized in a mixed system of a polymerization initiator, a dispersion medium and an inorganic dispersant according to any one of claims 1 to 3. Polymer particles. 6. A method comprising dissolving a polymer in a solvent using the inorganic dispersant according to claim 1 as a stabilizer and removing the solvent from a suspension dispersed and suspended in water. The resulting polymer particles. 7. An unsaturated polyester resin composition comprising the polymer particles according to claim 5 as a low-shrinking agent.