JP2000212288A - Composite particle and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite particle of various org. polymers and a layered clay mineral and to provide its simple manufacturing method. SOLUTION: This composite particle in which a layered clay mineral is minutely dispersed in org. polymers is manufactured by spraying the org. polymers, the layered clay mineral, and a uniformly mixed solution contg. an org. solvent or water into a heated inactive gas current or air current and thereby forming a particle. This composite particle contains 0.1-15 wt.% (based on the org. polymers) minutely dispersed layered clay mineral having an average aggregation thickness of 1-20 nm in the org. polymers, and has an average particle diameter of 5-200 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to composite particles in which a layered clay mineral is finely dispersed in an organic polymer, and a method for producing the same.

[0002]

2. Description of the Related Art A material obtained by compounding an organic polymer and an inorganic material has been widely studied for a long time. For example, various kinds of thermoplastic resins or thermosetting resins may be added to glass fibers, carbon fibers, mica, graphite, silica, A material in which heat resistance, mechanical properties, durability, and the like are improved by mixing particles, an inorganic material such as calcium carbonate, barium titanate, and the like is widely used.

[0003] In recent years, it has been studied to develop a more uniform and high-performance material by finely compounding an organic polymer and an inorganic material. In particular, composite materials in which a layered clay mineral is finely dispersed in a polyamide resin are widely studied because they exhibit excellent properties such as thermomechanical properties, mechanical properties, and gas shielding properties, and there are several different manufacturing methods. It has been reported.

For example, a method of performing melt polymerization of nylon 6 in-situ in the presence of a layered clay mineral (for example, A. Usuki, et.al, J. Mater. Res., 8, 1174 ( 199
3): JP-A-51-109998, JP-A-55-109998
38865, JP-A-62-74957, JP-A-63-230766, JP-A-64-1115
7, JP-A-6-248176),

[0005] Similarly, nylon 66 is used in the presence of a layered clay mineral.
Method for the interfacial polycondensation of (S. Idemura, K. Harraguch
i, Polym. Prep. Jpn., 46, 2835 (1997): JP-A-9-208
291) reports that a composite in which a layered clay mineral is finely dispersed in a nylon resin can be obtained.

Further, a method of kneading a layered clay mineral swollen with a lactam or the like and a polyamide resin to form a composite (Japanese Patent Publication No. 7-47644), or a method of co-dissolving nylon 66 and a layered clay mineral are used. Method for removing the solvent (Japanese Unexamined Patent Publication
8-245874) discloses a method for obtaining a complex.

[0007] In addition to the polyamide resin, a layered clay mineral is allowed to coexist with the polyamic acid, and then a ring is closed to form a composite with polyimide, or a polypropylene and a polyamide composite are kneaded to form a composite. Have been reported. However, these methods have problems in that the steps are complicated to obtain a particulate composite and are effective for individual systems but cannot be widely applied.

[0008]

An object of the present invention is to provide composite particles of various organic polymers and a layered clay mineral, and a simple production method thereof.

[0009]

SUMMARY OF THE INVENTION The present inventors spray and dry a homogeneous mixture containing an organic polymer, a layered clay mineral, an organic solvent or water in a heated inert gas stream or air stream. As a result, they have found that composite particles in which a layered clay mineral is finely dispersed in an organic polymer can be easily produced, and have completed the present invention.

That is, the present invention provides: (1) an organic polymer (A) having an average aggregate thickness of 1 to 20;
a composite particle having an average particle diameter of 5 to 200 μm, containing 0.1 to 15% by weight of the layered clay mineral (B) with respect to the organic polymer (A) in a finely dispersed state with respect to the organic polymer (A);

(2) The composite particles according to (1), wherein the organic polymer (A) is a phenol resin, an acrylic resin or a polyvinyl alcohol resin; and (3) the layered clay mineral (B) is hectorite. (1)
Composite particles according to,

(4) A homogeneous mixture containing an organic polymer (A), a layered clay mineral (B), an organic solvent (C) or water (D) is sprayed into a heated inert gas stream or air stream. A method for producing composite particles in which a layered clay mineral is finely dispersed in an organic polymer,

(5) The method for producing composite particles according to (4), wherein the average aggregate thickness of the layered clay mineral (B) finely dispersed in the organic polymer (A) is 1 to 20 nm; The method for producing composite particles according to (4), wherein the layered clay mineral (B) is 0.1 to 15% by weight based on the organic polymer (A); and (7) the average particle diameter is 5 to 200 μm. (4) The method for producing composite particles according to (4),

(8) The method for producing composite particles according to (4), wherein the organic polymer (A) is a phenol resin, an acrylic resin, or a polyvinyl alcohol resin; and (9) the layered clay mineral (B). Hectorite (4)
).

[0015]

DETAILED DESCRIPTION OF THE INVENTION The organic polymer (A) used in the present invention is selected from organic polymers which can be dissolved or homogeneously suspended in an organic solvent, for example, polymethyl methacrylate,
Acrylic resin such as polymethyl acrylate, polyhydroxyethyl methacrylate, nylon 6, nylon 6
6, amide resins such as poly m-phenylene isophthalamide, polyvinyl chloride, polystyrene, polyacrylonitonyl, polyvinyl alcohol,

[0016] Vinyl resins such as polyvinyl butyral, cellulose resins such as cellulose acetate, cellulose propionate and ethyl cellulose, ABS and poly-4-
Thermoplastic resins such as methylpentene-1, polycarbonate, and polysulfone; and thermosetting resins such as phenolic resin, epoxy resin, urea resin, melamine resin, and polyamic acid. Is used. Among them, a phenol resin, an acrylic resin, or a polyvinyl alcohol resin is preferably used.

In the layered clay mineral (B) used in the present invention, the clay layers are completely cleaved in an organic solvent (C) or water (D), and each layer is dispersed in a molecular or nearly molecular form. Those which give a uniform and transparent solution or those which give a uniform and translucent solution with sufficient affinity for the medium even if each layer is not dispersed in a molecular form are preferred.

Examples of the layered clay mineral (B) include layered silicate minerals, for example, smectite clay minerals such as hectorite, montmorillonite, saponite, beidellite, nontronite, and soconite. Hectorite is particularly preferred. Such a clay interlayer compound is dissolved in water when an alkali metal ion such as a sodium ion is present between layers, and is dissolved in an organic solvent when an organic ion is introduced between layers.

As the organic ions to be introduced between the layers, for example, alkylammonium ions such as methyltrioctylammonium ion, dimethyldioctadecylammonium ion and laurylammonium ion are used. As the organic solvent (C) used in the present invention, a solvent capable of dissolving or homogeneously suspending an organic polymer and a layered clay mineral into which an organic ion has been introduced is used. The boiling point of the organic solvent is preferably as low as possible to improve the yield of the composite, and particularly preferably lower than the softening point of the organic polymer (A).

The organic solvent is not particularly limited as long as the above conditions are satisfied. For example, methanol, ethanol,
Propanol, cyclohexanol, phenol, ethylene glycol, acetone, benzene, toluene, xylene, hexane, cyclohexane, methyl ethyl ketone, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N- 1 selected from methylpyrrolidone, quinoline, anisole, chloroform, dichloromethane, chlorobenzene, dimethyl ether, dimethyl sulfoxide, methylcellosolve, etc.
More than one kind of solvent or a mixed solvent is used.

In the present invention, when an organic polymer that dissolves or suspends in water is used as the homogeneous mixed solution, water is used as a solvent. In this case, a layered clay mineral that dissolves or suspends in water is used. On the other hand, when an organic polymer dissolved or suspended in an organic solvent is used, a layered clay mineral similarly dissolved or suspended in an organic solvent is used.

The average aggregate thickness of the layered clay mineral (B) in the composite particles in the present invention is 1 to 20 nm, preferably 1 to 5 nm. If the average aggregation thickness of the layered clay mineral (B) in the composite particles is 20 nm or more, the desired fine dispersion is not achieved, and the mixture becomes close to a blend obtained by simply kneading (B) and the organic polymer (A). The effect of improving physical properties is small.

The amount of the layered clay mineral (B) in the present invention may be any as long as the composite particles of the present invention can be prepared.
Can be selected according to the purpose. For example, heating the composite particles,
When post-processing by compression or the like, 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, particularly preferably 1 to 5% by weight, based on the organic polymer (A) is used. Can be

When the content of the layered clay mineral (B) is 0.1% by weight or less, the effect as a composite is small, and when the content of (B) is 15% by weight or more, the subsequent melt molding of the composite particles is high. Often difficult due to viscosity. On the other hand, when the composite particles are used in the form as it is, even if it is 15% by weight or more, it is effective. In the present invention, composite particles having 15% by weight or more of the layered clay mineral can be easily prepared.

The composite particles of the present invention can be manufactured in various sizes according to the purpose.
From the removal efficiency (production efficiency) of the organic solvent and the subsequent use conditions of the composite particles, the size of the composite particles is 500
μm or less, and particularly preferably those having an average particle size of 5 to 200 μm.

When the average particle size is less than 5 μm, the solid content ratio (NV%) in the homogeneous mixture is reduced, that is, the ratio of the organic solvent or water used is increased, or the gas amount is excessively increased. Need to be performed, and the manufacturing efficiency decreases. Further, even in subsequent use, handling may be difficult due to the fine powder. On the other hand, the average particle size is 200 μm
As described above, especially when the thickness is 500 μm or more, the removal of the organic solvent is often insufficient, and uniform composite formation cannot be performed in many cases.

In the present invention, as long as the homogeneity of the mixture is not impaired and the mixture does not gel, the low-molecular-weight or high-molecular-weight pigment, surfactant, plasticizer and the like may be used as the third component. , A curing agent, a surface treatment agent, an organic polymer other than A, rubber, and the like may be included in the composite particles.

On the other hand, in the present invention, a small amount of the organic solvent (C) or water (D) can be left in the composite particles, if necessary. This residual solvent may act as a plasticizer in the subsequent step of forming the composite particles to facilitate the processing of the composite molded article. The amount of the organic solvent (C) or water (D) contained in the composite particles is 10
% By weight or less, more preferably 0.1% by weight or less.
5 to 5% by weight.

When the amount of the solvent is 10% by weight or more, there are problems in that the composite particles stick to each other during storage at room temperature and tend to form a lump, and that foaming or the like is liable to occur during heating to a composite molded article. Come up. The lower limit of the residual solvent is not particularly limited.

A specific method for producing the composite particles of the present invention will be described below. A homogeneous mixture containing an organic polymer (A), a layered clay mineral (B), an organic solvent (C) or water (D) is sprayed into a heated inert gas stream or a heated air stream to form particles. When the organic solvent (C) is used, heated inert gas is used, and when water (D) is used, heated air is used.

As a specific apparatus for this particle formation, for example, an apparatus known as a spray-dry apparatus is used. The concentration of the homogeneous mixture (solid content of the resin and the layered clay mineral) is set as one of the production conditions so as to optimize the size of the composite particles, the amount of the remaining solvent, the production efficiency, and the like. The size of the obtained composite particles depends on the concentration, temperature, supply amount, droplet atomization method (for example, a disk type atomizer, a pressurized two-fluid nozzle, etc.) of the homogeneous mixed solution to be used and its conditions, inert gas or air. Temperature, flow rate, recovery method, and the like.

Here, the inert gas may be any gas which is safe for using an organic solvent, for example, nitrogen gas. The heating temperature of the inert gas or air is preferably equal to or higher than the boiling point of the organic solvent (C) or water (D), and more preferably equal to or lower than the softening point of the organic polymer. Also,
As the control temperature of the inert gas or air in the spray-drying apparatus, the inlet temperature is most effectively used among the inlet temperature, the outlet temperature, and the outlet temperature of the composite particles in the (pulverization) drying chamber. The outlet temperature is lower.

It is preferable that the temperature of the outlet of the composite particles be cooled to a lower temperature in order to prevent aggregation of the composite particles. It is also desirable to recover the removed organic solvent or water using a cooling device.

[0034]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. The percentages in the examples are on a weight basis unless otherwise specified.

(Example 1) Novolak type phenol resin (weight average molecular weight = 5700,
500 g of a phenol / formaldehyde ratio = 0.82, containing 10% by weight of hexamine, and a hectorite having dimethyldioctadecyl ammonium ion between layers as a layered clay mineral (B) (ideal composition formula: ((CH ₃ ) ₂ N)
_{[(CH 2) 1 7 CH} 3] 2) 0.33 (Mg 2.67 Li 0.33) S
25 g of i ₄ O ₁₀ (OH) ₂ , ash content = 56.2% by weight)
A homogeneous mixed solution containing 1300 g of toluene as the organic solvent (C) was prepared.

Using a CL-12 type spray dryer manufactured by Okawara Kakoki Co., Ltd., the mixed liquid was sprayed at a rate of 25 g / min from a two-fluid nozzle into a drying chamber through which a heated nitrogen gas stream flows. The nitrogen gas temperature at the inlet of the drying chamber was set at 120 ° C. (the gas temperature at the outlet was 77 ° C.), and the temperature of the particle capturing unit was set at 30 ° C. in combination with external cooling. In the present example, the homogeneous mixed liquid became fine particles immediately after being sprayed from the nozzle portion, and C was rapidly removed from the fine particles under a stream of heated nitrogen gas to form composite particles composed of A and B.

The average particle size of the obtained composite particles was 28 μm as measured by a scanning electron microscope. The average composition of the composite particles obtained from thermogravimetric analysis (measurement under a flow of air from room temperature to 600 ° C .: heating rate 10 ° C./min) is as follows:
Resin: inorganic content: solvent = 97.2: 2.8: 3 (weight ratio). The obtained composite particles were stored at 25 ° C. for one month and observed, but were not aggregated into a lump. Also, from transmission electron microscopic measurement of an ultrathin section prepared by embedding the obtained composite particles in an epoxy resin, the average aggregate thickness of the layered clay mineral contained in the composite particles was 2.1 nm. .

(Examples 2 to 4) Organic polymers shown in Table 1
Using an organic solvent, and a rotating disk atomizer
And in Examples 3 and 4, in the layered clay mineral
Ion of (C_TwoH_Five) _TwoCH_ThreeN (CH_TwoCH (CH_Three) C
H_TwoOH) as in Example 1 except that
To prepare composite particles of organic polymer and layered clay mineral
Was. Table 1 shows the properties of the obtained composite particles.

The resol type phenol resin of Example 3 in Table 1 is a resol type phenol resin having a weight average molecular weight = 1700 and a phenol / formaldehyde ratio of 1.2, and the polyacryl resin of Example 4 is It is a copolymer resin having an average molecular weight of 550,000 and a copolymerization ratio of polymethyl methacrylate / polymethyl acrylate = 67/33.

[0040]

[Table 1]

Example 5 As an organic polymer (A),
500 g of vinyl alcohol resin, layered clay mineral (B)
With sodium ions between layers as hectorite
(Ideal composition formula Na _0.33(Mg_2.67Li_0.33) Si_FourO
_Ten(OH)_TwoAsh content = 82.3% by weight)
A homogeneous mixture containing 1500 g of (D) was prepared.

The mixture was sprayed at a rate of 25 g / min from a two-fluid nozzle into a drying chamber under a heated air stream. The nitrogen gas temperature at the inlet of the drying chamber was set at 120 ° C. (the gas temperature at the outlet was 69 ° C.), and the temperature of the particle capturing unit was set at 20 ° C. using external cooling. In this example, the homogeneous mixed solution became fine particles immediately after being sprayed from the nozzle portion, and D was rapidly removed from the fine particles under a stream of heated air, whereby composite particles composed of A and B were developed. According to this example, the average particle size is 40 μm (measured by scanning electron microscope).
Was obtained.

The average composition of the composite particles determined by thermogravimetric analysis (measurement under flowing air from room temperature to 600 ° C .: heating rate 10 ° C./min) is: resin: inorganic content: water = 95.3: 4 .7:
4 (weight ratio). The obtained composite particles are at 25 ° C.
After storage for one month, there was no agglomeration into a lump.
Further, from the transmission electron microscope measurement of an ultrathin section prepared by embedding the obtained composite particles in an epoxy resin, the average aggregate thickness of the layered clay mineral contained in the composite particles was 3.1 n.
m.

[0044]

The present invention relates to a molding material, an electric / electronic part,
A layered clay mineral is finely dispersed and compounded in an organic polymer, useful as various materials such as machine parts, automobile parts, sporting goods and heat-resistant parts.
And a method for producing the same. The obtained composite particles are molded as they are or by heat compression or the like, and are used as a material having excellent heat resistance, mechanical properties, slidability and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) C08L 101/00 C08L 101/00 F term (reference) 4F070 AA26 AA29 AA44 AC27 AD01 AE01 CA01 CA16 CB12 DA33 DA34 DC07 4J002 AA001 BE021 BG001 CC041 DE027 DJ006 DJ056 FA016 FD207 HA06

Claims (9)

[Claims] 1. An organic polymer (A) comprising a layered clay mineral (B) having an average aggregation thickness of 1 to 20 nm is finely dispersed in an amount of 0.1 to 15% by weight based on the organic polymer (A). Composite particles having an average particle size of 5 to 200 μm. 2. The organic polymer (A) is a phenol resin,
The composite particles according to claim 1, which is an acrylic resin or a polyvinyl alcohol resin. 3. The composite particles according to claim 1, wherein the layered clay mineral (B) is hectorite. 4. A homogeneous mixture containing an organic polymer (A), a layered clay mineral (B), an organic solvent (C) or water (D) is sprayed into a heated inert gas stream or air stream. A method for producing composite particles in which a layered clay mineral is finely dispersed in an organic polymer, characterized in that the composite particles are formed into particles. 5. The method for producing composite particles according to claim 4, wherein the average aggregate thickness of the layered clay mineral (B) finely dispersed in the organic polymer (A) is 1 to 20 nm. 6. The method according to claim 4, wherein the content of the layered clay mineral (B) is 0.1 to 15% by weight based on the weight of the organic polymer (A). 7. The method for producing composite particles according to claim 4, wherein the average particle size is 5 to 200 μm. 8. The method for producing composite particles according to claim 4, wherein the organic polymer (A) is a phenol resin, an acrylic resin, or a polyvinyl alcohol resin. 9. The method according to claim 4, wherein the layered clay mineral (B) is hectorite.