JPH0212975B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing true spherical polyester resin fine powder.

Polyester resins, particularly polyethylene terephthalate, have extremely good physical properties and are therefore widely used as materials for clothing and industrial and daily life-related uses.

However, when this polyester resin is used as a lubricant, a sliding material, an additive to cosmetics, a porous polymer material, etc., it is necessary to use a truly spherical fine powder due to its smoothness, smoothness, feel, and filling properties. It is required that the polyester resin be pulverized into a perfect spherical shape.

Conventionally, various methods have been tried to powderize polyester resin, but due to the toughness of the polyester resin, it is extremely difficult to grind and powderize it.
Furthermore, excessive frictional heat generated during pulverization has a significant negative effect on resin quality.

As a method to eliminate such obstacles in crushing and powdering, there are two methods: immersing the resin in an ultra-low temperature liquid, such as liquid nitrogen at -147°C or lower, and then pulverizing it in a crusher; or using various solvents, such as polyethylene. In the case of terephthalate, methods such as dissolving the resin in a chlorinated hydrocarbon and then removing the solvent to obtain a powder are known. A method in which a polyester resin having a viscosity of 200 to 3000 poise when melted is injected with a high-speed heated gas is injected into a granular solid and then solid-phase polymerized (Japanese Patent Publication No. 46-3192, Japanese Patent Publication No. 46-3193). A method of solid-phase polymerization after forming a fine solid (Japanese Patent Publication No. 37596/1983), a method of heat-treating drawn or undrawn yarn until its melting point exceeds 285°C and then pulverizing it (Japanese Patent Publication No. 1983-37596)
35241) have also been proposed.

However, in any of the above-mentioned methods, it is difficult to form a powder that is perfectly spherical and fine, and the requirements for the above-mentioned uses have not yet been met.

In view of the current situation, the present inventors have completed the present invention as a result of extensive research into true spherical resin fine powder and a method for producing the same.

The purpose of the present invention is to produce a true spherical polyester resin in the form of a fine powder, which has excellent physical properties such as smoothness, smoothness, feel, fillability, as well as toughness, hardness, abrasion resistance, and weather resistance. This provides industrial advantages.

In order to achieve the above object, the present invention has the following configuration. That is, the gist of the present invention is to heat and melt a polyester resin having an average degree of polymerization of less than 30 or a reduced viscosity of less than 0.25, and to direct the molten raw material resin in the direction of movement of high-speed pressurized gas.
The gas is collided and merged with the incident contact angle θ of 30° or more, and is injected from the nozzle, and the maximum particle size obtained is
True spherical fine powder not exceeding 100 microns is produced under reduced pressure.
Alternatively, there is provided a method for producing a truly spherical polyester resin fine powder, which is characterized by carrying out solid phase polymerization in a heated inert atmosphere.

The term "true spherical fine powder" as used in the present invention refers to one in which spherical bodies having a smooth circular surface substantially account for 90% or more of the number of particles when observed using an optical magnifying microscope, as shown in Figure 1. , a spherical body is the diameter of the maximum circle circumscribing the projected image of one particle (φ
mm) divided by the diameter (φmin) of the smallest circle circumscribing the projected image of the particle, which satisfies the relationship expressed by the following equation (1).

φmm/φmin≦1.5 (1) Spherical particles have the above external shape, but even if they are so-called hollow spheres that contain one or more gas bubbles such as air, nitrogen, or carbon dioxide inside. In addition, there are no particular limitations on the shape and size of the bubbles. Further, the content ratio of the hollow cells to the total spherical particles is not particularly limited.

Furthermore, the incident contact angle in the present invention is, for example, the sixth contact angle.
In the structure of the nozzle shown in the figure, the contact angle between the two fluids is such that the center line of the molten raw resin blowing hole 11 and the center line of the high-speed pressurized gas blowing passage 8 intersect with each other at an angle θ at the nozzle center 10. say.

In addition, the reduced viscosity in the present invention refers to phenol 60
Mixed solvent of 40 parts by weight and 40 parts by weight of tetrachloroethane
The value measured by dissolving 1 g of sample in 100 ml at 35°C is converted into the value measured with orthochlorophenol.

In the production method of the present invention, it is first necessary to obtain a raw material polyester resin having a predetermined degree of polymerization that can be jetted easily by a nozzle, but according to research by the present inventors, the range of degree of polymerization that satisfies this condition is It was confirmed that the average degree of polymerization due to repeating units was less than 30 and the reduced viscosity as defined above was less than 0.25.

The average degree of polymerization of the raw material polyester resin is 30 or more,
When the ring identity is 0.25 or more, the melt viscosity becomes relatively high, 50 to 100 poise or more, so that the polyester resin sprayed from the nozzle becomes fine fibers as shown in Figure 2, and the objects and effects of the present invention are achieved. cannot be achieved.

Next, the raw polyester resin obtained under the above conditions is heated and melted, and is injected from a nozzle together with high-speed pressurized gas.

Here, when injecting from the nozzle, it is necessary that the molten raw material resin and the high-speed pressurized gas collide and merge at an incident contact angle θ of 30° or more with respect to the traveling direction of one of the fluids, By injecting under these conditions, the maximum particle size as shown in Figure 1 can be achieved.
True spherical fine powder of no more than 100 microns can be obtained at a ratio of 80% or more by weight based on the raw material.

Furthermore, even when the incident contact angle θ is 90° or more, it naturally holds true in the sense that the formation of a truly spherical powder is caused by the impact energy caused by the collision between the molten raw material and the high-speed pressurized gas, as described later.

However, when the incident contact angle θ is less than 30°, the impact energy due to the collision between the molten raw material and the high-speed pressurized gas is insufficient, resulting in the formation of fibers with non-uniform thickness or non-uniform morphology as shown in Figure 3. The resulting powder becomes particulate, making it impossible to obtain the desired true spherical fine powder.

The method of the present invention involves injecting raw material polyester resin from a nozzle together with high-speed pressurized gas under the above conditions,
The feature is that it is easy to obtain true spherical polyester resin fine powder as shown in FIG.

In the present invention, an apparatus for producing true spherical fine powder is shown in FIG. 5, for example.

Raw material polyester resin with an average degree of polymerization of less than 30 and a reduced viscosity of less than 0.25 is stored in heating storage tank 1 shown in Figure 5.
continuously or intermittently, and heated in the presence of an inert gas such as nitrogen gas at a temperature range of 10 to 110° C. higher than the melting point of the raw material resin to maintain its melting state. This molten raw material resin passes through a conduit 2 that is heated and kept warm, and is quantitatively fed into a spray nozzle 5 by a metering gear pump 3 that is heated and kept warm.

If the melting temperature of the raw polyester resin is higher than its melting point and lower than 10°C, it is not preferable because the raw resin may stick to a part of the conduit and nozzle, causing clogging. Also, 110% lower than the melting point of the raw material resin.
If the resin is melted at a temperature higher than 0.degree. C., the raw resin will decompose rapidly and the product will be markedly colored, so it is not appropriate to use this temperature condition.

The heated molten raw material resin quantitatively sent out by the gear pump 3 collides with the high-speed pressurized gas guided from the gas blowing pipe 4 in the heated and heat-retained spray nozzle 5, and the impact energy causes deformation. The molten resin becomes unstable and begins to split from the surface of the molten resin, and the split molten resin continues to repeatedly collide with the gas flow to become atomized particles, and is guided to the intermediate tank 6 while becoming spherical due to the action of the surface tension of the molten resin itself.

The spray nozzle used here has a structure as shown in FIG. 6, for example.

A high-speed pressurized gas blowing passage 8 passes horizontally through the interior center of the main body outer shell 7, and a molten raw resin passage 9 is arranged around the circle. The high-speed pressurized gas and the molten raw material resin pass through each passage, merge at a nozzle 10 provided at the tip of the main body, and are continuously blown out by the kinetic energy of the high-speed pressurized gas.

In this nozzle structure, the angle θ where the center line of the molten raw resin blowing hole 11 and the center line of the high-speed pressurized gas blowing passage 8 intersect at the nozzle center 10
In order to efficiently turn the molten raw resin into a truly spherical powder, it is necessary that the relationship expressed by the following formula (2) be satisfied.
In addition, the inner diameter of the molten raw resin blowing hole 11 is d ₁ , the inner diameter of the gas blowing passage 8 is d ₂ , and the inner diameter of the nozzle center is
d ₃ , the inner diameter of the nozzle outlet is d ₄ , the length of the nozzle inlet taper is l ₁ , the length of the nozzle center straight pipe is l ₂ , and the length of the nozzle outlet taper is l ₃ d ₁ , d ₂ , d ₃ ,
It is desirable that the relationships of formulas (3) to (7) hold between d ₄ and l ₁ , l ₂ , and l ₃ .

(Unit: mm) θ≧30゜ (2) d ₃ ≧1.5d ₁ (3) 0.5 (d 4 − d 3 ) ＜ l ₃ ＜ _8.3 (d ₄ − d ₃ ) ( ₄ ) 0.4 (d ₂ − d ₃ ) < l ₁ < 3.3 (d ₂ - d ₃ ) (5) 0.25d ₃ < l ₂ < 3.0d ₃ (6) 0.5d ₃ < l ₃ < 8.3d ₃ (7) Applying impact energy to the raw polyester resin As the high-speed pressurized gas that has an important effect, room temperature or heated air, nitrogen, carbon dioxide, etc. may be used. The pressure of the gas blown into the nozzle here is at least 0.5Kg/cm ² . G is desirable. Gas pressure is 0.5Kg/cm ² . If it is less than G,
As the kinetic energy of the gas decreases, the impact energy given to the raw resin becomes insufficient, and the number of random fibers with uneven thickness or particulate structures with uneven shapes increases significantly. It is not possible to obtain a truly spherical fine powder.

The polyester resin obtained as described above has an average degree of polymerization of less than 30, or a reduced viscosity of less than 0.25, and contains 80% by weight of true spherical fine powder with a maximum particle size not exceeding 100 microns based on the raw materials used. It is contained in the above ratio. The true spherical fine powder not exceeding 100 microns from which 20% by weight or less of fine heterogeneous structures have been removed can be used for the above-mentioned purposes, such as lubricants,
When used as a slipping material, an additive to cosmetics, a porous polymer material, etc., it fully satisfies the requirements for smoothness, smoothness, feel, fillability, etc. However, in the above applications, toughness,
Naturally, hardness, weather resistance, abrasion resistance, etc. are also required.

Therefore, the true spherical resin fine powder of the present invention has to have various physical properties such as toughness, hardness, weather resistance, abrasion resistance, etc., that is, an average degree of polymerization of 4 or more, or a reduced viscosity of 0.1 or more. It is polymerized by solid phase polymerization until it becomes .

The solid phase polymerization method may be any conventional known method, for example, under a reduced pressure of 5 mmHg or less, or under a heated inert gas atmosphere, at a temperature of 5 to 100 mm below the melting point of the resin.
Solid state polymerization is carried out at temperatures in the low range of °C. The reaction time at this time is not particularly limited and can be appropriately adjusted depending on the required physical properties of the final powder product. Furthermore, if the physical properties of the final product are to have an average degree of polymerization of 4 to 30 or a reduced viscosity of 0.1 to 0.25, it is clear that it is not necessary to carry out the solid phase polymerization operation as described above.

The final product obtained in this way is made of polyester resin with an average degree of polymerization of 4 or more or a reduced viscosity of 0.1 or more, and is a true spherical resin fine powder with a maximum particle size not exceeding 100 microns, and has smoothness and smoothness. It has excellent physical properties such as tactility, fillability, toughness, hardness, weather resistance, and abrasion resistance.

The polyester resin in the present invention refers to all polyester polymers consisting of a dibasic acidic component and a glycol component, but particularly preferred are polyethylene terephthalate resins, copolyesters mainly composed of ethylene terephthalate, etc. A copolyester resin comprising at least 60% by weight of ethylene terephthalate units. Such copolymerized polyester resins include, for example, polyethylene terephthalate as a main component, and isophthalic acid, adipic acid, sebacic acid, naphthalene-2,6-dicarboxylic acid,
Dicarboxylic acid components such as 1,4-cyclohexanedicarboxylic acid, succinic acid, and glutaric acid, trimethylene glycol, tetramethylene glycol,
Diethylene glycol, cyclohexane-1,4
- Examples include copolymerized polyethylene terephthalate, which is a copolymerization of glycol components such as dimethanol, pentaerythritol, and polyethylene glycol.

The raw material polyester resin can be produced by a conventionally known batch method or continuous polymerization method, and is used in a state in which commonly used polycondensation catalysts, stabilizers, titanium oxide, pigments, etc. are added in advance.

In the injection of the molten raw material polyester resin in the present invention, the molten raw material resin is collided with the traveling direction of the high-speed pressurized gas at an incident contact angle θ of 30° or more, and the impact energy causes splitting and atomization. The spray nozzle is not particularly limited to the spray nozzle exemplified above.

In addition, the raw resin fine particles after being injected are slowly cooled by the gas injected at the same time and are made into true spheres by the surface tension effect of the resin itself, but the cooling conditions are not particularly limited to slow gas cooling. For example, a liquid spray such as water may be used.

In this way, a polyester resin with an average degree of polymerization of less than 30 or a reduced viscosity of less than 0.25 is heated and melted, and the molten raw material resin is heated at an incident contact angle θ of 30° or more with respect to the direction of movement of the high-speed pressurized gas. Collision with the gas
The particles are merged and injected from the nozzle until the maximum particle size is
Since a true spherical fine powder not exceeding 100 microns can be obtained, the true spherical fine polyester resin powder obtained by solid-phase polymerization under reduced pressure or under heating in an inert atmosphere has an average degree of polymerization of 4. or more, or the reduced viscosity is 0.1 or more, and the maximum particle size is 100
It has physical properties on the order of microns or less, and is suitable for a very wide range of uses, such as lubricants, slipping materials, additives for cosmetics, porous polymer materials, and other industrial and lifestyle-related materials.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 100 parts by weight of dimethyl terephthalic acid, 68 parts by weight of ethylene glycol, and 0.05 parts by weight of manganese acetate were heated to a temperature of 140 to 220°C under a nitrogen atmosphere, and methanol as a by-product was continuously distilled off to the outside. After carrying out the transesterification reaction for 2.5 hours, 0.03 parts by weight of trimethyl phosphate, 0.5 parts by weight of titanium dioxide, and 0.05 parts by weight of antimony trioxide were further added thereto. Next, the temperature of this transesterification product is
After raising the temperature to 295°C and distilling off excess ethylene glycol, the polycondensation reaction was carried out under reduced pressure of 0.5 mmHg with stirring for 0.2 hours.

The obtained polycondensate had a melt viscosity of 12 poise when melted at 275°C, and when it was taken out and slowly cooled in a nitrogen atmosphere, it became a solid mass with relatively brittle properties, and the reduced viscosity as defined above was 0.20.
The average degree of polymerization was 25.

This polyethylene terephthalate resin was put into the heating storage tank 1 shown in Fig. 5, and the
It was melted by heating to a temperature of ℃. Conduit 2 where this molten polyethylene terephthalate is heated and kept at 300℃
The mixture was quantitatively transferred through a gear pump 3 to a spray nozzle 5 which was also heated and kept at 300°C.

Pressurized nitrogen controlled at 5 kg/cm ² G was passed through the spray nozzle from the gas blowing pipe 4 in advance, and the mixture was injected together with the molten polyethylene terephthalate, and the mixture was evacuated and slowly cooled in the intermediate tank 6.

The nozzle used here has a structure as shown in Fig. 6, with d ₁ = 0.6 mmφ, d ₂ = 4.5 mmφ, d ₃
= 1.5mmφ, d ₄ = 2.1mmφ, l ₁ = 5.0mm, l ₂ = 1.5mm,
l ₃ = 2.5 mm, θ = 90°.

As a result of removing fine heterogeneous structures equivalent to 5.0% by weight from the thus obtained propellant, the reduced viscosity
0.18, an average degree of polymerization of 23, and a shape as shown in FIG. 1, a true spherical fine powder with a maximum particle size of 100 microns or less and an average particle size of 40 microns was obtained.

Example 2 The true spherical polyethylene terephthalate resin fine powder obtained in Example 1 was transferred to a solid phase polymerization apparatus in which the reaction tank itself rotates, and after drying at 140°C for 1.0 hour under a reduced pressure of 50 mmHg, the temperature was lowered to 240°C. ℃, 1.0
When a solid phase polymerization reaction was carried out for 10 hours under reduced pressure of mmHg, the reduced viscosity was 0.68, the average degree of polymerization was 105, the maximum particle size was 100 microns or less, and the average particle size was 40 microns.
The resulting fine spherical polyethylene terephthalate resin powder had a good shape and excellent physical properties such as abrasion resistance and toughness.

Example 3 100 parts by weight of terephthalic acid, ethylene glycol
45 parts by weight and 0.05 parts by weight of antimony trioxide were continuously supplied to the first reaction tank, and the mixture was heated at 260°C under normal pressure.
After carrying out an esterification polycondensation reaction for 3.0 hours and distilling off the by-product water, it is sent to a second reaction tank where 0.5 parts by weight of titanium dioxide and triphenyl phosphate are added.
0.03 parts by weight was added and a continuous polycondensation reaction was carried out at 200 mmHg and 275°C for 1.5 hours. This polycondensate was taken out under a nitrogen atmosphere, slowly cooled, and had a viscosity of 7 when melted at 275°C.
Polyethylene terephthalate with a reduced viscosity of 0.14 and an average degree of polymerization was obtained.

This polyethylene terephthalate resin was heated at a resin melting temperature of 290° C. and a pressurized nitrogen pressure of 2.5 Kg/cm ² in Example 1. Exactly the same method except for G.
The device sprayed it with a nozzle.

7.5% by weight from the propellant thus obtained
After removing a considerable amount of fine heterogeneous structures, a solid phase polymerization reaction was carried out for 7 hours in the same manner as in Example 2. As a result, the reduced viscosity was 0.5, the average degree of polymerization was 80, and the maximum particle size was 100.
A perfectly spherical polyethylene terephthalate resin fine powder having an average particle diameter of 50 microns or less as shown in FIG. 1 was obtained.

The true spherical polyethylene terephthalate resin fine powders obtained in Examples 1, 2, and 3 have excellent properties such as smoothness, smoothness, feel, fillability, as well as toughness, hardness, weather resistance, and abrasion resistance. It has excellent physical properties and satisfies the conditions for advantageous use in lubricating properties, slipping materials, additives for cosmetics, porous polymer materials, etc.

Comparative Example 1 After carrying out the transesterification reaction and distilling off excess ethylene glycol under exactly the same conditions as in Example 1, a polycondensation reaction was carried out for 0.5 hours under reduced pressure of 0.5 mmHg. This polycondensate was taken out under a nitrogen atmosphere,
Slow cooling, viscosity when melted at 280°C: 200 poise, reduced viscosity
A polyethylene terephthalate resin with an average degree of polymerization of 0.34 was obtained.

When this polyethylene terephthalate resin was injected through a nozzle using exactly the same method and apparatus as in Example 1, only a very light fine fibrous material as shown in FIG. 2 could be obtained.

Furthermore, high-speed pressurized nitrogen pressure was applied to 8Kg/cm ² . G was used for nozzle injection, but the results were the same as above except that the diameter of the fine fibers became smaller.

Comparative Example 2 A transesterification reaction and distillation of excess ethylene glycol were carried out under exactly the same conditions as in Example 1,
Immediately take it out under a nitrogen atmosphere and slowly cool it to 275℃.
A polyethylene terephthalate lump having a melting viscosity of 0.3 poise, a reduced viscosity of 0.08, and an average degree of polymerization of 3 was obtained.

When this polyethylene terephthalate was injected through a nozzle in exactly the same manner as in Example 3, the maximum particle size was
It became a perfectly spherical fine powder with an average particle size of 40 microns or less than 100 microns.

This true spherical fine powder was very brittle and easily destroyed by a slight external force.

Comparative Example 3 The polyethylene terephthalate resin obtained by the continuous polycondensation reaction of Example 3 was prepared using the apparatus shown in Fig. 5 and having the structure shown in Fig. 6.
d ₁ = 0.6mmφ, d ₂ = 4.5mmφ, d ₃ = 1.5mmφ, d ₄ = 2.1
Using a nozzle with dimensions of mmφ, l ₁ = 5.0 mm, l ₂ = 1.5 mm, l ₃ = 2.5 mm, and θ = 25°, the resin melting temperature was 290°C,
Pressurized nitrogen pressure 2.5Kg/ ^cm2 . It was injected under G conditions.

The resulting structure was in the form of fibers and particles with a non-uniform morphology, as shown in FIG.

Comparative Example 4 The polyethylene terephthalate resin obtained by the continuous polycondensation reaction of Example 3 was subjected to pressurized nitrogen pressure.
0.35Kg/ ^cm2 . Nozzle injection was performed using the same method and apparatus as in Example 3, except that G was used.

As soon as injection started, resin solids adhered to the tapered part at the tip of the nozzle, obstructing the normal flow of the injection material. The structure thus obtained was a mixture of random fibers with non-uniform thickness and particles with non-uniform morphology, and no truly spherical fine powder could be obtained.

Comparative Example 5 The polyethylene terephthalate resin obtained by the polycondensation reaction of Comparative Example 1 was coarsely pulverized in advance by a rotary impact type pulverizer until it passed through an 8 mesh screen, and then finely pulverized in a dry state by a ball mill. A polyethylene terephthalate resin fine powder of 100 microns or less was obtained by sieve classification.

As shown in FIG. 4, the particle structure of this powder is crushed with many corners, and compared to the true spherical fine powder obtained in Examples 1, 2, and 3, it has smoothness, smoothness, and smoothness. It lacked tactility.

[Brief explanation of drawings]

Fig. 1, Fig. 2, and Fig. 3 are enlarged schematic diagrams of fine powder by nozzle injection, Fig. 4 is an enlarged schematic diagram of pulverized fine powder, and Fig. 5 is the production of true spherical fine powder. An example of a device for this purpose is shown below. FIG. 6 shows an example of a cross-sectional view of a nozzle for producing true spherical fine powder.

Claims (1)

[Claims] 1. A polyester resin having an average degree of polymerization of less than 30 or a reduced viscosity of less than 0.25 is heated and melted, and the molten raw material resin is heated and melted at an incident contact angle θ of 30° or more with respect to the direction of movement of high-speed pressurized gas. A true spherical fine powder having a maximum particle size not exceeding 100 microns is solid-phase polymerized under reduced pressure or under heating in an inert atmosphere. A method for producing spherical polyester resin fine powder. 2. The manufacturing method according to claim 1, wherein the high-speed pressurized gas is blown into the nozzle at a pressure of at least 0.5 Kg/cm ² G. 3. The manufacturing method according to claim 1, wherein the raw material polyester resin is a polyethylene terephthalate resin or a copolyester resin mainly composed of ethylene terephthalate units. 4 The copolymerized polyester resin is mainly composed of polyethylene terephthalate, and isophthalic acid,
Adipic acid, sebacic acid, naphthalene-2,6-
at least one dicarboxylic acid component selected from dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, and glutaric acid, trimethylene glycol, tetramethylene glycol,
Diethylene glycol, cyclohexane-1,4
- The manufacturing method according to claim 3, wherein at least one glycol component selected from dimethanol, pentaerythritol, and polyethylene glycol is copolymerized.