JP2833459B2 - Device for preventing fusion of polyester granules - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing fusion of polyester particles.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate, have various excellent properties and are therefore used in a wide range of fields as materials for fibers, films, bottles and the like. In general, polyester obtained by polymerizing a polymerization reaction is discharged from a reaction tank, solidified, cut, and temporarily formed into polyester granules. The polyester granules contain moisture, and when melt-molded as it is, hydrolysis occurs to lower the degree of polymerization and cause deterioration of the quality of the melt-molded product. Therefore, when the polyester granules are melt molded, a drying treatment is indispensable.

For example, in the case of drying polyethylene terephthalate, the drying is generally performed at 150 ° C. to 200 ° C. for several hours. However, polyester obtained by copolymerizing the third component and polyester granules that have been rapidly cooled when cut into granules are fused to the inner wall of the dryer in the drying step to reduce the drying efficiency or to mutually fuse. It was agglomerated and clumped and was difficult to discharge from the dryer. As a method of avoiding these problems, for example, Japanese Patent Application Laid-Open No. 4-239606 proposes a method in which a shear stress is applied to a polyethylene terephthalate chip using a device such as a Henschel mixer to roughen the chip surface. In addition, Japanese Patent Publication No. 39-154
No. 43 proposes a method of stretching a strand-shaped or sheet-shaped molded product and then cutting it into particles to prevent deformation and fusion of the particles during heating and drying. In addition, a method is known in which a polyester granular material is heated and cooled to perform a preliminary crystallization using a preliminary crystallization device such as a paddle dryer or a hopper dryer.

[0004]

However, the method disclosed in Japanese Patent Application Laid-Open No. 4-239606 for applying a shear stress to a chip to roughen the chip surface can prevent fusion, In known processing apparatuses such as a Henschel mixer and a V blender, the apparatus takes up a large space. For uniform treatment, usually 3 to 20
It takes a long time, and it is difficult to connect the polymer cutter and the process to perform a continuous process, and the number of processes increases until the drying process. Furthermore, powder of the product is generated by the treatment, but the powder has a high degree of crystallinity and part of it remains without melting during melt molding, causing yarn breakage in the spinning process and significantly impairing transparency in the film forming process. Affects sliding characteristics. For this reason, there is a problem that a powder removing step is required.

In the method disclosed in Japanese Patent Publication No. 39-15443, deformation and fusion of particles can be prevented, however, since a strand-shaped or sheet-shaped molded article and its particles are oriented by stretching, the molded article is When the particles are formed into particles, cutting becomes difficult, and extra-size products called miscuts increase, which causes troubles in the next process and causes significant wear of the cutter. In addition, a part remains without being melted at the time of melt molding, and there remains a problem that the characteristic value of a molded product is lowered and transparency is significantly impaired.

When a device such as a paddle drier or a hopper drier is used, the polyester granules fused by heating are crystallized while being crushed by a stirrer, so that the shape of the polyester granules after crystallization becomes irregular. In addition, not only loss due to crushing of a large amount of polyester granules at the time of crushing occurs, but also long-term treatment is required, productivity is reduced, and production cost tends to be increased.
Further, in the above method, since pre-crystallization is performed by heating and cooling, energy loss is large, and polyethylene terephthalate is disadvantageous in that the intrinsic viscosity [η] is reduced by about 0.01 dl / g, which is not preferable. Further, in some cases, fusion occurs due to the physical properties of the polyester granules, and the purpose cannot be sufficiently achieved.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the prior art described above, and to efficiently rub the polyester granules together to crystallize the surface of the polyester granules, thereby improving the drying. It is an object of the present invention to provide a fusion preventing device capable of providing a polyester granule which does not cause fusion to an inner wall of the machine or fusion between polyester granules.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for preventing fusion of polyester particles, comprising a rotor and a screen, and a polyester particle passage between the rotor and the screen. Achieved by the device.

The rotor refers to a cylindrical rotating body that rotates inside the screen, and has an action of rotating to take in the polyester particles. The rotor preferably has a projection on its surface to improve the fir action, and more preferably has a slit hole for blowing out gas to have the function of cooling the polyester granules and separating generated powder.

[0010] The screen is a plate installed at a distance in the circumferential direction of the rotor, and secures a passage of the polyester granules in pairs with the rotor. The screen has a circular cross section in the direction perpendicular to the rotation direction of the rotor, preferably a polygonal shape such as an octagon, and has a number of projections inside. More preferably, it refers to one having a large number of slit holes and having a function of flowing gas from the polyester granule side.

An example of the fusion prevention device of the present invention will be described in detail with reference to FIG. The following device is an example, and the present invention is not limited to this device.

The embodiment of the present invention shown in FIG. 1 has the following mechanism to effectively achieve the above object. That is, the inlet 1 for the granular material, the pulley 5 and the shaft 2 transmitted from the motor by a belt or the like, the granular material transporting screw 3 and the rotor 4 directly connected to the shaft 2, the bearing 6 for supporting the rotating part thereof,
It comprises a screen 7 for holding the granular material, a discharge port 8 after the processing of the granular substance, a body cover 9 and a gas supply port 10 for reducing the powder in the granular substance and the heat generation of the device, and a discharge port 11 thereof. .

[0013]

When a predetermined amount of polyester granules is supplied from the inlet 1, the polyester granules are fed between the rotor 4 and the screen 7 by the transport screw 3, which is rotating in advance.

The rotor 4 is rotating at a high speed of 300 to 800 rpm, and the polyester particles are efficiently interposed between the octagonal screen 7 and the rotor 4 having projections. By this rare action, the surface of the polyester granules is crystallized.

The polyester particles subjected to the crystallization treatment are as follows:
It is pushed by the new polyester granules fed by the screw 3 and is discharged out of the system through the discharge port 8.

During this time, due to the strong and rare action of the polyester granules, heat is generated from the polyester granules and powder is generated due to the peeling of the polyester granules. The gas supplied from the gas supply port 10 passes through the inside of the screw 3 and the inside of the rotor 4, blows out from the slit of the rotor 4, passes through the gap between the polyester granules, conveys the generated powder and heat, and passes through the screen 7. It passes through the slit hole and is discharged out of the system through the discharge port 11.

[0017]

The present invention will be described in more detail with reference to the following examples. In addition, the physical property in an Example was measured as follows.

A. Fused state in the dryer The fused state rank of the polyester granules in the dryer is:
X is determined and determined by the following equation. X ≦ 1.0 ◎ 1.0 <X ≦ 10.0 ○ 10.0 <X ≦ 50.0 △ 50.0 <X ×

B. Intrinsic viscosity [η] Polyester granules were dissolved in O-chlorophenol and measured at 25 ° C with an Ubbelohde capillary viscometer.

C. Amount of powder 1 kg of polyester granules are divided into several portions on a 10-mesh sieve and washed with water, and the obtained washing water is filtered through a 10-micron nickel screen. The material on the filter was determined as a powder.

D. Model fusion rate 100ml beaker (Iwaki glass: 1000BK10
In 0), 30 g of polyester granules are taken. A weight is put into a 50 ml beaker (Iwaki glass: 1000BK50) so that the total weight becomes 160 g. A 50 ml beaker weighed to 160 g is placed on a 100 ml beaker in which polyester granules are weighed. The beaker is placed in a drier heated to 170 ° C. (treat for 1 hour under normal pressure). Upon completion of the treatment, the weight is quickly removed, and the mixture is allowed to cool at room temperature for 30 minutes. Two or more fused polyester granules are weighed as a fused product. Fusion rate = weight of fused material / total weight × 100 (wt%). At the same time, n = 3 or more is measured, and the average value is used as the fusion rate.

Example 1 After an esterification reaction was carried out using terephthalic acid and ethylene glycol as main raw materials, a polycondensation reaction was carried out using antimony trioxide as a catalyst, and the intrinsic viscosity [η] was 0.680 dl /.
g of polyethylene terephthalate was obtained. The obtained polyethylene terephthalate was granulated using a strand cutter. The above-mentioned polyester granules were treated with the apparatus shown in FIGS. 1 and 2 under the conditions of a rotor rotation speed of 800 rpm and a polyester granule supply speed of 9.0 t / hr. There was no change in the intrinsic viscosity [η] of the polyester granules before and after the treatment. The powder amount of the treated polyester granules was 30 ppm.
When a fusion test was performed on the polyester particles after the treatment, the model fusion ratio was as good as 11% by weight. The treated polyester granules were treated with a fluid bed type dryer at a drying temperature of 175 ° C. and a drying time of 1.5 hours, but there was no adhesion of the polyester granules to the inner surface of the dryer.
There was also no fusion between the granules.

Example 2 The polyester granules obtained in the same manner as in Example 1 were
Rotor having protrusions as shown in FIG.
8. Using a device equipped with a square screen, rotor rotation speed 800 rpm, feeding speed of polyester granules 9.
The treatment was performed under the condition of 0 t / hr. There was no change in the intrinsic viscosity [η] of the polyester granules before and after the treatment. The powder amount of the treated polyester granules was 3
It was 0 ppm. When a fusion test is performed on the treated polyester particles, the model fusion ratio is 3 wt%.
Was better than that of Example 1. The treated polyester granules were subjected to the same drying treatment as in Example 1, but the polyester granules did not adhere to the inner surface of the dryer.
There was also no fusion between the granules.

Comparative Example 1 A polyester granule obtained in the same manner as in Example 1 except that no treatment was performed was subjected to the same drying treatment as in Example 1.

Comparative Example 2 20 kg of polyester granules obtained in the same manner as in Comparative Example 1
Was put into a Henschel mixer, and the mixture was stirred at a rotation speed of 960 rpm for 15 minutes to carry out a treatment, followed by the same drying treatment as in Comparative Example 1.

Comparative Example 3 The polyester granules obtained in the same manner as in Comparative Example 1 were treated with a paddle dryer at a rotation speed of 10 rpm, a set temperature of 110 ° C., and a residence time of 8 minutes. Was done.

[0027]

[Table 1]

[0028]

The polyester granules obtained by the apparatus according to the present invention can prevent the fusion of the polyester granules to each other and the adhesion to the inner wall of the dryer in the drying step. Since the apparatus according to the present invention is small and has a short processing time, the apparatus can be connected to a granulating apparatus for converting a polyester from a molten state into granules, and continuous production can be performed without increasing the number of steps.

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view of one embodiment of the present invention shown in an example.

FIG. 2 is a plan sectional view of a rotor, a shaft, and a screen in FIG.

FIG. 3 shows another embodiment of a rotor screen that can be suitably used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Granular material input port 2 ... Shaft 3 ... Conveying screw 4 ... Rotor 5 ... Pulley 6 ... Bearing 7 ... Screen 8 ... Discharge port 9 ... Main body cover 10 ... Air supply port 11 ... Air discharge port

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29B 9/16

Claims (5)

(57) [Claims] 1. An apparatus for preventing fusion of polyester particles, comprising a rotor and a screen, and a polyester particle passage between the rotor and the screen. 2. The apparatus according to claim 1, wherein the rotor has protrusions. 3. The apparatus for preventing fusion of polyester granules according to claim 1, wherein the cross-sectional shape of the screen is polygonal. 4. The apparatus according to claim 1, further comprising a screw for conveying the polyester granules. 5. The rotor and the screen have gas circulation holes, and have a mechanism for separating the powder of polyester particles generated in the system through the screen to the outside of the system by gas blown from the inside of the rotor. The apparatus for preventing fusion of a polyester granular material according to any one of claims 1 to 4, characterized in that: