JP4663305B2 - Method for producing flaky glass aggregate and flaky glass aggregate - Google Patents

Description

  The present invention relates to a method for producing an aggregate of flaky glass and a flaky glass aggregate.

  Flaked glass is used for various applications. For example, a thermoplastic resin containing flaky glass exhibits excellent characteristics as a molding material.

  However, since the flaky glass is a fine particle, there is a problem that the flaky property is high in the state as it is and the workability until blended with the thermoplastic resin is poor. Therefore, conventionally, a method of agglomerating flaky glass into a granule has been proposed (see, for example, Patent Documents 1 and 2).

Aggregates of flaky glass can be formed by spraying a solution containing a resin on the flaky glass and stirring, followed by drying. This drying is usually performed at a temperature of 100 ° C. or higher. Since the aggregate after drying needs to be discharged from the production line as soon as possible, the aggregate of flaky glass is generally enclosed in a packaging container without cooling after drying.
JP-A-63-225554 Japanese Patent Laid-Open No. 2-124732

  However, the conventional manufacturing method has a problem that flake glass aggregates further aggregate in the packaging container to form a large mass (secondary aggregate). Such a large lump has a problem that it is difficult to take out from the packaging container and it is difficult to uniformly knead it with a resin material such as a plastic pellet.

  In view of such a situation, an object of the present invention is to provide a method for producing a flaky glass aggregate that does not form a large lump in a packaging container.

  As a result of studies to achieve the above object, the present inventors have found that the flake-shaped glass aggregates form large lumps due to the condensation that occurs in the packaging container. When the flaky glass aggregate dried at a temperature of 100 ° C. or higher is enclosed in the packaging container without being cooled, the initial temperature in the packaging container becomes about 100 ° C. or higher. Thereafter, condensation occurs in the packaging container as the temperature in the packaging container decreases, and this condensation forms aggregates together to form a large lump. Based on such new knowledge, the present inventor has come up with the present invention.

  The production method of the present invention includes a first step of forming an aggregate of the flake glass by drying a mixture containing the flake glass and a binder at a temperature of 100 ° C. or higher, and 80% of the aggregate. A second step of cooling to a temperature below 0 ° C. and a third step of enclosing the cooled aggregate in a packaging container.

  The flaky glass aggregate of the present invention is a flaky glass aggregate produced by the production method of the present invention.

  According to the production method of the present invention, flake glass aggregates can be prevented from further agglomerating in the packaging container to form a large lump. According to this method, a granular flaky glass having no large variation in size even when stored in a packaging container can be obtained.

  Hereinafter, embodiments of the present invention will be described.

  The production method of the present invention includes a first step of forming an aggregate of flaky glass by drying a mixture containing flaky glass and a binder at a temperature of 100 ° C. or higher, and the aggregate is 80 ° C. or lower. A second step of cooling to a second step and a third step of enclosing the cooled aggregate in a packaging container.

  Flaked glass is scaly glass. The size of the flaky glass is not particularly limited, but it is preferable that the average particle diameter (simple average of the longest diameter) is in the range of 5 to 2000 μm and the average thickness is in the range of 0.5 to 20 μm. When the average particle size is less than 5 μm, the function as a reinforcing material may be lowered. On the other hand, when the average particle size exceeds 2000 μm, it becomes difficult to agglomerate and the dispersibility in the resin decreases. Moreover, it is not easy to produce flaky glass having an average thickness of less than 0.5 μm. In addition, flaky glass having an average thickness of more than 20 μm may easily clog the gate portion of the extrusion molding machine.

  The aspect ratio (average particle diameter) / (average thickness) of the flaky glass is preferably in the range of 2 to 1000. When the aspect ratio is less than 2, it is difficult to produce a sufficiently large aggregate. On the other hand, if the aspect ratio exceeds 1000, the dispersibility when the flaky glass aggregate is dispersed in the resin may be lowered. Especially, the effect of this invention is large in the flaky glass which (average particle diameter) / (average thickness) exists in the range of 30-120.

The flaky glass may be provided with a metal and / or metal oxide thin film on its surface. The flaky glass may contain a considerable amount of alkali metals and alkaline earth metals (hereinafter collectively referred to as “alkali components”) as composition components. In that case, the alkali component may be eluted from the surface of the flaky glass, which may cause a problem that the adhesive force between the thermoplastic resin and the flaky glass is lowered or discolored. In such a case, elution of alkali components can be suppressed by providing a thin film made of, for example, silica (SiO ₂ ) in advance on the surface of the flaky glass. Moreover, a specific color tone can be imparted to the resin composition containing the flaky glass aggregate by forming a thin film having a specific thickness. Moreover, the external appearance of a resin composition can be changed by providing a metal thin film.

  The binder (binder) used in the production method of the present invention is obtained by agglomerating flaky glass into granules. As the binder, for example, a dispersion in which a resin is dispersed in a solvent or a solution in which a resin is dissolved in a solvent can be used. The binder may contain a silane coupling agent, and may further contain other components such as a surfactant, an antifoaming agent, and an antistatic agent. As the solvent, water or an organic solvent can be used depending on the resin.

  Examples of the resin contained in the binder include acrylic resin, epoxy resin, phenol resin, vinyl acetate, and urethane resin. Among these, the epoxy resin and the urethane resin are familiar with the silane coupling agent and the thermoplastic resin. Therefore, the resin contained in the binder is preferably at least one resin selected from an epoxy resin and a urethane resin. When the binder contains these resins and a silane coupling agent, the flake glass and the thermoplastic resin are firmly bonded in the composition obtained by dispersing the flaky glass aggregate in the thermoplastic resin. Therefore, an excellent reinforcing material can be obtained. In particular, the application of the present invention is effective when the binder contains an epoxy resin.

  There is no limitation in particular in the quantity of resin (resin in binder) with respect to 100 mass parts of flake shaped glass, For example, you may select in the range of 0.1 mass part-5 mass parts.

  The mixture is formed by mixing materials such as flaky glass and a binder. There is no particular limitation on the mixing method. At this time, the solution of the binder may be sprayed and added while stirring the flaky glass with a mixer.

  In the first step, an aggregate is formed by drying the mixture at a temperature of 100 ° C. or higher. Drying may be performed under conditions that allow the solvent in the mixture to be efficiently removed. For example, the drying can be performed by heat treatment at a temperature in the range of 100 ° C. to 200 ° C. for about 5 minutes to 60 minutes. In addition, you may perform drying, stirring a mixture.

  In the second step, the aggregate formed in the first step is cooled to 80 ° C. or lower (preferably 70 ° C. or lower, more preferably 40 ° C. or lower). As a typical cooling method, there is a method of blowing cold air. For example, a gas (for example, air) of 40 ° C. or lower (preferably 25 ° C. or lower) may be sprayed. By blowing and cooling a gas of 40 ° C. or less, it is possible to enclose the aggregates in the packaging container without scattering the granular flakes from the line, and the flake glass aggregates can be produced with high productivity. .

  The wind speed of the blowing gas is preferably less than 1.5 m / s. When gas is blown at a wind speed of 1.5 m / s or more, aggregates that are blown away increase. The wind speed of the sprayed gas is more preferably in the range of 1.0 m / s to 1.5 m / s. By setting it as this range, an aggregate can be cooled rapidly, preventing scattering of the aggregate. Moreover, although there is no limitation in particular in the direction which sprays the gas for cooling, scattering of the aggregate can be suppressed by spraying the gas for cooling from the upper direction of the aggregate moving on the belt conveyor.

  In the third step, the cooled aggregate is enclosed in a packaging container. A metal can, a container, a packaging bag, etc. are used as a packaging container. The maximum temperature in the packaging container in which the aggregate is enclosed is approximately equal to the temperature of the aggregate immediately before being enclosed in the packaging container. In the production method of the present invention, since the aggregate is cooled to 80 ° C. or lower in the second step and then packaged, the maximum temperature in the packaging container is 80 ° C. or lower. Here, since the amount of water (water vapor) that can be held in the air in the packaging container that is substantially sealed is determined by the saturated water vapor pressure in the packaging container, the amount of water vapor that is held in the air in the packaging container as the temperature increases. Increases and condensation tends to occur. Since the amount of saturated water vapor in the air at 80 ° C. is low enough to suppress the generation of secondary aggregates, the production method of the present invention can suppress the generation of secondary aggregates in the packaging container. . In particular, by cooling the aggregates to 70 ° C. or lower in the second step, the generation of secondary aggregates can be effectively suppressed.

  FIG. 1 is a schematic diagram showing the manufacturing process of the manufacturing method of the present invention. The mixture 10 containing the flaky glass aggregate and the binder is dried in the drying furnace 11, cooled by the cooling device 12, and enclosed in the packaging container by the packaging device 13. Note that these devices may be integrated. In addition, another device, for example, an inspection device or a sorting device may be arranged between these devices.

  As described above, according to the present invention, it is possible to suppress the generation of secondary aggregates, and it is possible to obtain flake-shaped glass aggregates that are easy to use with few excessively large lump.

  Hereinafter, the present invention will be described in detail by way of examples.

Example 1
A flake glass having an average particle diameter of 600 μm (manufactured by Nippon Sheet Glass Co., Ltd., Micro Glass (registered trademark), glass flake (registered trademark) REF-600) is supplied to the rotating disk type mixer at a rate of 100 kg / hour. The binder solution was added and mixed at a rate of 40 kg / hour while stirring to obtain flake glass aggregates. As the binder solution, a mixture of a silane coupling agent (1% by mass), an epoxy resin emulsion (2% by mass), and water (97% by mass) was used. As the resin of the epoxy resin emulsion, bisphenol A type epoxy resin (solid resin softening point: about 102 ° C.) was used.

The flaky glass aggregate thus obtained was dried at 120 ° C. for 30 minutes in a hot air dryer. Immediately after the drying, 30 ° C. cold air is uniformly applied to the flake glass aggregate at a wind speed of 0.5 m / s or less with a fan-shaped air nozzle and cooled, and the cooled aggregate is a flexible rubber rubber having a capacity of 1 m ^3. Enclosed in a container. And the temperature of the flaky glass aggregate in a container was measured. Further, 48 hours after the enclosure, the presence or absence of dew condensation in the container and the occurrence of large lumps of flaky glass were observed.

(Example 2)
A flaky glass aggregate was prepared and evaluated in the same manner as in Example 1 except that the resin used for the epoxy resin emulsion was changed. In Example 2, a bisphenol A type epoxy resin (solid resin softening point: about 135 ° C.) was used as the resin of the epoxy resin emulsion.

(Comparative Example 1)
In the same manner as in Example 1, flake glass and a binder were mixed to obtain an aggregate of flake glass. The agglomerate was dried in a hot air dryer at 120 ° C. for 30 minutes, and then enclosed in a rubber flexible container having a capacity of 1 m ³ . In Comparative Example 1, cooling after drying with a hot air dryer was not performed. The same evaluation as Example 1 was performed about the aggregate enclosed in the container.

(Comparative Example 2)
In the same manner as in Example 2, the flake glass and the binder were mixed to obtain an aggregate of flake glass. The agglomerate was dried in a hot air dryer at 120 ° C. for 30 minutes, and then enclosed in a rubber flexible container having a capacity of 1 m ³ . In Comparative Example 2, cooling after drying with a hot air dryer was not performed. The same evaluation as Example 1 was performed about the aggregate enclosed in the container.

  Table 1 shows sample preparation conditions and evaluation results of Examples 1-2 and Comparative Examples 1-2.

  As shown in Table 1, the peak temperature of the aggregates in the containers in Examples 1 and 2 was 70 ° C. This temperature is considered to be substantially equal to the temperature of the flaky glass aggregate just before being enclosed in the container, that is, the temperature of the flaky glass aggregate after cooling.

  The flake glass aggregates of the examples stored for 48 hours in containers were evaluated for size by sieving. As a result, it was 0.5% by mass or less when it did not pass through a sieve having an aperture of 4 mm, and 90% by mass or more did not pass through a sieve having an aperture of 150 μm. Such an aggregate is particularly good in handling during use. On the other hand, when the flake glass aggregate of Comparative Example 1 stored in a container for 48 hours was similarly evaluated for the size by sieving, it was 20% by mass that did not pass through a 4 mm sieve. 90% by mass did not pass through the 150 μm sieve.

  The present invention is applicable to flake glass aggregates. The aggregate can be used in various applications, for example, as a reinforcing material for a thermosetting resin or a thermoplastic resin, or as a filler for anticorrosion lining.

It is the schematic which shows the manufacturing method of this invention typically.

Explanation of symbols

10 Mixture 11 Drying furnace 12 Cooling device 13 Packaging device

Claims (4)

A first step of forming an aggregate of the flaky glass by drying a mixture containing the flaky glass and a binder at a temperature of 100 ° C. or higher;
A second step of cooling the aggregate to 80 ° C. or lower;
And a third step of enclosing the cooled aggregate in a packaging container.   The method for producing a flaky glass aggregate according to claim 1, wherein the flaky glass has a value of (average particle diameter) / (average thickness) in the range of 2 to 1000.   The method for producing a flaky glass aggregate according to claim 1, wherein the flaky glass has a value of (average particle diameter) / (average thickness) in the range of 30 to 120. The manufacturing method of the flaky glass aggregate of any one of Claims 1-3 which cools the said aggregate by spraying the gas of 40 degrees C or less to the said aggregate in a said 2nd process.