JP2002018844A - Apparatus for preventing fusion bonding of polyester granular material and method for manufacturing surface crystallized polyester granular material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for preventing fusion bonding of a polyester granular material and a method for manufacturing a surface crystallized polyester granular material capable of efficiently crystallizing a surface of the polyester granular material, suppressing fusion bonding to an inner wall of a dryer, fusion bonding between polyester granular materials or occurrence of a powder, and providing the polyester granular material having a predetermined shape. SOLUTION: The apparatus for preventing fusion bonding of a polyester granular material comprises a rotor, a screen installed in a circumferential direction of the rotor, a conveying screw, and a polyester granular material passage provided between the rotor and the screen, in such a manner that a thickness of an outermost periphery of a section of a vertical direction of a spiral part of the screen is smaller than a thickness of an innermost periphery. The method for manufacturing a surface crystallized polyester granular material comprises the step of shearing the polyester granular material buy using the apparatus for preventing the fusion bonding of the polyester granular material.

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, which can efficiently crystallize the surface and suppress generation of powder.

[0002]

2. Description of the Related Art Polyesters, especially polybutylene terephthalate, have excellent moldability, heat resistance, mechanical properties, chemical resistance, etc., and are therefore used as molding materials for electric parts and automobile parts, and as soft materials. It is widely used for fibers by taking advantage of its stretch properties. In general, polyester discharges the polymer after the polymerization reaction from the reaction tank,
The mixture is solidified and cut, and once made into polyester granules. The polyester granules contain water, 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.

[0003] For example, in the case of drying polybutylene terephthalate, it is generally carried out at 90 ° C to 160 ° C for several hours. Polyester granules that have been subjected to cooling have a problem that the amorphous layer on the surface is relatively thick, so that they are fused together in the drying step to form agglomerates, or that they are fused to the inner wall of the dryer to reduce the drying efficiency. There was something. As a method for avoiding these problems, Japanese Patent Application Laid-Open No. Hei.
No. 6 proposes a method of applying a shear stress to a polyethylene terephthalate chip using a device such as a Henschel mixer to roughen the chip surface. In addition, special public 39-
Japanese Patent No. 15443 proposes a method of stretching a strand-shaped or sheet-shaped molded article and then cutting the same to prevent the particles from being deformed or fused during heating and drying as particles. 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.

Japanese Patent Application Laid-Open No. Hei 7-171829 discloses that polyester particles are efficiently rubbed against each other and the surface of the polyester particles is crystallized, whereby the polyester particles are fused to the inner wall of a dryer or the polyester particles are interposed. An apparatus for suppressing fusion has been proposed.

[0005]

However, the method of applying a shear stress to roughen the chip surface as disclosed in Japanese Patent Application Laid-Open No. 4-239606 can prevent fusion, but, for example, a Henschel mixer. And V-blenders require large equipment, take up space, and usually take 3 to 20 minutes to process uniformly. It is difficult to connect the polymer cutter to the process and perform continuous processing. And the number of processes increases. In addition, powder of the product is generated by the treatment, but the powder has a high degree of crystallinity, and some of the powder remains without being melted during the melt molding, causing thread breakage in the spinning process, and in the film forming process, Significantly impairing transparency,
Affects sliding characteristics. For this reason, there remains a problem that a step of removing the powder is required.
In addition, when a device such as a paddle dryer or a hopper dryer is used, since the polyester particles fused by heating are crystallized while being crushed by a stirrer, the shape of the polyester particles 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, so that productivity tends to decrease and manufacturing cost tends to increase. In addition, any of the methods is disadvantageous in that since pre-crystallization is performed by heating and cooling, energy loss is large and intrinsic viscosity [η] is reduced. Further, in some cases, fusion occurs due to the physical properties of the polyester granules, and this method cannot be said to be a method for sufficiently achieving the object.

[0006] Next, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 7-171829, although the fusion rate is low, the weight of the roller is applied, and in addition to the pressure when pushing up with the roller,
By applying a large amount of friction between the outside and the wall of the transport screw, the polyester granules may become a film,
There is a problem that a large amount of powder is generated.

[0007] In view of the problems of the prior art, the present invention can efficiently crystallize the surface of the polyester granules, and also fuses the polyester granules to the inner wall of the dryer and the fusion between the polyester granules. An object of the present invention is to provide an anti-fusion device and a method for producing surface-crystallized polyester particles, which can suppress adhesion and generation of powder and can provide polyester particles having a uniform shape.

[0008]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the apparatus for preventing fusion of the polyester granules of the present invention is a fusion prevention apparatus including a rotor, a screen installed in a circumferential direction of the rotor, and a conveying screw. It has a polyester granular material passage between, and, characterized in that the thickness of the outermost peripheral portion of the vertical section of the spiral portion of the conveying screw is smaller than the thickness of the innermost peripheral portion, The method for producing a surface-crystallized polyester granule according to the present invention is characterized in that the polyester granule is subjected to a shearing treatment using the apparatus for preventing fusion of the polyester granule.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to solve the above-mentioned problem, that is, it is possible to efficiently crystallize the surface of the polyester granules, and furthermore, to fuse them to the inner wall of the dryer or to fuse them between the polyester granules. Of the fusion prevention device capable of suppressing the generation of dust and powder and providing a uniform-shaped polyester granular material, and in the polyester granular material passage, the outermost peripheral portion of the vertical section of the spiral portion of the conveying screw in the conveying screw When the thickness of the inner peripheral portion was made smaller than the thickness of the innermost peripheral portion, the polyester granules can be efficiently rubbed against each other,
Thus, it has been found that such a problem can be solved at once.

It has also been found that the use of such an anti-fusion device allows a polyester granule to be subjected to a shearing treatment and to efficiently produce a surface-crystallized polyester granule.

An example of the fusion prevention device of the present invention will be described in detail with reference to FIG. 1, but the present invention is not limited to such a device.

FIG. 1 shows an inlet 1 for a granular material, a pulley 5 transmitted from a motor by a belt or the like, a shaft 2, a granular material conveying screw 3 and a rotor 4 directly connected to the shaft 2, and a bearing for supporting a rotating part thereof. 6, a screen 7 for holding the granular material, a discharge port 8 after the processing of the granular substance, a main body cover 9 and a gas supply port 10 for reducing the powder in the granular substance and heat generation of the device, and a discharge port 11 thereof. ing.

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

The transport screw 3 is for transporting the polyester granular material as shown in FIG. It is important that the thickness of the outermost peripheral portion of the vertical section of the spiral portion of the transport screw is smaller than the thickness of the narrow inner peripheral portion, as shown in FIG. 4, and such a spiral portion is tapered. preferable. As such a tapered shape, the taper angle is preferably in the range of 10 ° to 80 °, and 40 ° to 5 °.
An angle of 0 ° is more preferred.

Further, it is preferable that a groove exists on the surface of the spiral portion of the conveying screw as shown in FIG. 3, and the groove preferably has a pitch of 2 mm to 10 mm, and preferably has a pitch of 4 mm to 6 mm. Are more preferred. Further, the depth of the groove is preferably from 0.2 mm to 2.0 mm, more preferably from 0.8 mm to 1.2 mm.

The rotor 4 is a cylindrical rotating body that rotates inside the screen 7, and has an action of causing the polyester granules to rotate when rotating. The form of the rotor 4 is to improve the fir action.
Those having projections on the surface thereof are preferable, and those having a slit hole for blowing gas are more preferably used. The latter having a blowing slit hole has a function of cooling the polyester granules and separating generated powder.

The screen 7 is a plate provided at a distance in the circumferential direction of the rotor 4, and secures a passage of the polyester granules in pairs with the rotor 4. The form of the screen 7 is not particularly limited.
It is preferable that the cross section in the vertical direction with respect to the rotation direction is polygonal, and more preferable that the cross section is octagonal as shown in FIG. The screen 7 preferably has a large number of protrusions on the inside thereof, and further has a large number of slit holes thereon, which is particularly preferably used since gas flows from the polyester granule side.

The rotor 4 is usually 300 to 800 rpm
By rotating at a high speed, between the clean 7 and the rotor 4, the polyester granules are efficiently put together and rubbed.

The shearing treatment means that the surface of the polyester granules is crystallized by this rare action. The sheared and crystallized polyester granules are converted into new polyester granules fed by the conveying screw 3. It is pushed and discharged out of the system through the discharge port 8.

During this time, due to the strong and rare action between the polyester granules, heat is generated from the polyester granules and powder is generated due to the peeling of some of the polyester granules. The gas supplied from the air supply port 10 passes through the inside of the conveying screw 3 and the inside of the rotor 4, blows out from the slit of the rotor 4, passes through the gaps between the polyester granules, and conveys the generated powder and heat to the screen 7. After passing through many slit holes, the air is discharged from the air outlet 11 to the outside of the system.

The polyester used in the present invention is not particularly limited, including unsaturated polyester, but preferably a thermoplastic polyester resin is used. As such thermoplastic polyester resin, terephthalic acid or esters thereof, ethylene glycol, propylene glycol, butanediol, pentadiol,
Neopentyl glycol, hexanediol, octanediol, decanediol, cyclohexanedimethanol, hydroquinone, bisphenol A, 2,2-bis (4-hydroxyethoxyphenyl) propane, 1,4
Terephthalic acid-based polyesters obtained from glycols such as dimethylol tetrabromobenzene are preferably used, and among them, polyethylene terephthalate and polybutylene terephthalate are preferable, and polybutylene terephthalate is particularly preferable.

Such polybutylene terephthalate is
Terephthalic acid is used as the main dicarboxylic acid component, and 1,4-butanediol is used as the main glycol component.This refers to a high-molecular-weight thermoplastic polyester having an ester bond in the main chain.Other acid components include isophthalic acid and orthophthalic acid. An acid, naphthalenedicarboxylic acid, oxalic acid, adipic acid is used, and as a diol component, 1,4-cyclohexanedimethanol, bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or the like can also be used. Each of these components is preferably used in a range of 40 mol% or less based on terephthalic acid or 1,4-butanediol.

According to the present invention, a surface-crystallized polyester granule can be produced by subjecting the polyester granule to a shearing treatment using the apparatus for preventing fusion of the polyester granule. That is, polyester granules such as polybutylene terephthalate are heated at a flow rate of 1.1 m ³ / min by using hot air at a temperature of 110 to 150 ° C. for 150 minutes.
After drying in the range of ~ 200 minutes, it is supplied to the anti-fusion device by the conveying screw 3 at a rate of preferably 1 to 8 t / hour, more preferably 2 to 4 t / hour. This polyester granule is
By means of the rotor 4, the screen 7 and the transport screw 3, the granules are well rubbed and evenly rubbed, so that the surface of the polyester granules can be crystallized quickly and efficiently. The temperature of the space between the main body cover 9 and the screen 7 of the fusion prevention device is preferably 10 to 70 ° C, more preferably 20 to 70 ° C.
The temperature is preferably 40 ° C.

[0024]

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 by the following equation (1) and determined.

[0025]

(Equation 1)

[0026] B. Intrinsic viscosity [η] Polyester granules were dissolved in O-chlorophenol and measured at 25 ° C with an Ubbelohde capillary viscometer. C. Measurement of powder amount 1 kg of the polyester granules is washed several times with water on a 10-mesh sieve, and the obtained washing water is filtered through a 10-micron nickel screen. The retentate was collected as a powder. D. Model fusion rate (1) 100ml beaker (Iwaki glass: 1000BK10
In 0), weigh 30 g of the polyester granules.

(2) 50 ml so that the total weight becomes 160 g
A weight is put into a beaker (Iwaki glass: 1000B K50).

(3) 100 m weighed polyester granules
Place a 50 ml beaker weighed to 160 g on the l beaker.

(4) Place the beaker in a dryer heated to 130 ° C. (treat for 1 hour under normal pressure). (5) When the treatment is completed, immediately remove the load and allow to cool at room temperature for 30 minutes.

(6) Two or more fused polyester granules are weighed as a fused product.

(7) Fusing rate = weight of fused material / total weight × 10
It is represented by 0 (wt%).

(8) At the same time, n = 3 or more are measured, and the average value is used as the fusion rate. Example 1 After performing an esterification reaction using terephthalic acid and 1,4-butanediol as main raw materials, a polycondensation reaction was performed using an organic tin compound and an organic titanium compound as catalysts, and the intrinsic viscosity [η] was 0.881 dl /. g of polybutylene terephthalate was obtained. The obtained polybutylene terephthalate was granulated by a cutter. As shown in FIGS. 1, 2, 3, and 4, the above-mentioned polyester granules were formed by using a conveying screw device having a groove on the spiral outer portion and having a taper. The treatment was performed under the condition of a body supply speed of 4.0 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 particles was 7 ppm, and no film was generated. When a fusion test was performed on the polyester particles after the treatment, the model fusion ratio was as good as 1% by weight.
The treated polyester granules were treated with a fluidized bed type dryer at a drying temperature of 130 ° C. and a drying time of 1.5 hours, but there was no adhesion of the polyester granules to the inside of the dryer,
There was no fusion between the granules. Comparative Example 1 The obtained polyester granules were prepared in the same manner as in Example 1 except that the outermost peripheral portion and the innermost peripheral portion of the spiral portion of the transport screw were the same as shown in FIG. The same drying treatment was performed. Comparative Example 2 After performing an esterification reaction using terephthalic acid and 1,4-butanediol as main raw materials, a polycondensation reaction was performed using an organic tin compound and an organic titanium compound as catalysts, and the intrinsic viscosity [η] was 0.881 dl /. g of polybutylene terephthalate was obtained.

The obtained polybutylene terephthalate was granulated with a cutter, and 20 kg of polyester granules were charged into a Henschel mixer, and the mixture was stirred at 960 rpm for 15 minutes to carry out a treatment. The same drying treatment as in Comparative Example 1 was carried out. Was. Comparative Example 3 After performing an esterification reaction using terephthalic acid and 1,4-butanediol as main raw materials, a polycondensation reaction was performed using an organic tin compound and an organic titanium compound as catalysts, and the intrinsic viscosity [η] was 0.881 dl /. g of polybutylene terephthalate was obtained.

The obtained polybutylene terephthalate is granulated with a cutter, and the polyester granules are subjected to rotation at 1 rpm.
At 0 rpm, at a set temperature of 110 ° C., and at a residence time of 8 minutes, a treatment with a paddle dryer was performed, and the same drying treatment as in Comparative Example 1 was performed.

[0035]

[Table 1]

As is clear from Table 1, the apparatus using the apparatus of Example 1 has a significantly lower model fusion ratio and powder generation amount than the apparatuses using the apparatuses of Comparative Examples 1 to 3, and also has a dryer. It turns out that it is excellent without being fused to the inner wall.

[0037]

According to the present invention, it is possible to stably and continuously produce polyester molded articles such as fibers and films.

According to the apparatus for preventing fusion of polyester granules of the present invention, it is possible to prevent fusion between polyester granules in the drying step and adhesion to the inner wall of the dryer, and to prevent film-like debris and powder. In addition, such an apparatus can be connected to a granulating apparatus for converting a polyester from a molten state to a granular body because the apparatus is small and the processing is short, so that the number of steps is increased without increasing the number of steps. It has the advantage that it can be produced.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an embodiment according to the present invention.

FIG. 2 is a plan sectional view of a main part of the rotor, shaft, and screen of FIG. 1;

FIG. 3 is an explanatory view of a transport screw part of FIG. 1;

FIG. 4 is a side view of a transport screw part of FIG. 1;

FIG. 5 is a side view of a transport screw portion according to a conventional example.

[Explanation of symbols]

 1: Granular material input port 2: Shaft 3: Conveying screw 4: Rotor 5: Pulley 6: Bearing 7: Screen 8: Discharge port 9: Body cover 10: Air supply port 11: Air discharge port

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F070 AA47 BB06 DB08 4F201 AA24 AC01 AR12 BA04 BC01 BC02 BC12 BC19 BN03 BN05 BN50 BP26 BQ04 BQ16 BQ47

Claims (4)

[Claims] 1. A fusion prevention device comprising a rotor, a screen provided in a circumferential direction of the rotor, and a conveying screw, comprising a polyester particulate passage between the rotor and the screen. A fusion prevention device for polyester granules, wherein the thickness of the outermost peripheral portion of the spiral section of the conveying screw in the vertical direction is smaller than the thickness of the innermost peripheral portion. 2. The conveying screw according to claim 1, wherein the spiral portion has a tapered shape.
3. The apparatus for preventing fusion of polyester granules according to item 1. 3. The conveying screw according to claim 1, wherein the spiral portion has a groove on the surface.
3. The apparatus for preventing fusion of polyester granules according to item 1. 4. A method for producing surface-crystallized polyester granules, comprising subjecting the polyester granules to shearing treatment using the apparatus for preventing fusion of polyester granules according to claim 1.