JP4595347B2 - Method for producing polyester resin powder, method for producing polyester preform, and apparatus for heat treatment of polyester resin powder - Google Patents

Description

  The present invention relates to a method for producing a polyester resin powder. Specifically, when the heated gas is brought into contact with the polyester resin powder, the polyester resin powder can be heat-treated more efficiently and the product quality can be further homogenized. The present invention relates to a method for producing resin powder.

  In general, polyester is produced by esterification of an aromatic dicarboxylic acid component such as terephthalic acid and a diol component such as ethylene glycol, and melt polymerization of the esterified product, and solid phase polymerization is performed as necessary. By the way, in the solid phase polymerization of polyester, the diffusion time of the diol component in the resin powder is reaction-controlled, and in order to reduce this rate-limiting, a method of increasing the diffusion rate by increasing the temperature, powder particle size A method for reducing the diffusion distance by reducing the distance is known.

  Currently, industrial solid-phase polymerization equipment widely used industrially is a tower-type fixed bed (moving bed) type apparatus that continuously supplies raw materials from the top and continuously discharges products from the bottom. . In such a system, the residence time distribution of the powder becomes small, but there is a problem that, for example, a powder having a small particle diameter of 1 mm or less becomes difficult to handle due to the occurrence of bridging. Therefore, the apparatus as described above is not suitable for the above-described method for reducing the particle size of the powder.

  On the other hand, if the fluidized bed is formed by flowing an inert gas, it is possible to efficiently contact the resin powder having a small particle diameter of approximately 1.5 mm or less and the inert gas. Therefore, it is desirable to form a fluidized bed in order to perform the solid phase polymerization reaction by a method of reducing the particle size of the powder and reducing the diffusion distance in order to shorten the reaction time. Many techniques using such a fluidized bed have been disclosed, and examples of application to solid phase polymerization of polyester are also known (see, for example, Patent Documents 1 and 2).

U.S. Pat. No. 4,165,420 US Pat. No. 4,205,157

  For example, in a process in which the quality such as molecular weight and acetaldehyde content changes depending on the reaction time (residence time), such as solid phase polymerization of polyester, it is important to make the residence time distribution as small as possible. In general, since a fluidized bed is characterized by being a completely mixed bed, when a raw material is continuously supplied and a product is discharged in a continuous process including a fluidized bed reactor, the residence time of the product in the fluidized bed reactor. There is a problem that the distribution becomes large and products that have not yet been reacted or products that have reacted excessively are discharged. That is, in the known method in which the above-described solid phase polymerization of polyester is performed in a fluidized bed, since one fluidized bed is used, there is a problem that the residence time distribution of the product becomes large and the product quality is not stable.

  The present invention has been made in view of the above circumstances, and the object thereof is to make it possible to heat the polyester resin powder more efficiently by bringing the heated gas into contact with the polyester resin powder. An object of the present invention is to provide a method for producing polyester resin powder by heat treatment of polyester resin powder, which can further homogenize the quality.

  As a result of intensive investigations to achieve the above object, the present inventors have used a plurality of processing containers constituting a fluidized bed in parallel, and switched and supplied polyester resin powder to the plurality of processing containers. By successively executing the heat treatment of the polyester resin powder in the container and the discharge of the treated polyester resin powder from the treatment container with a phase difference for each treatment container, continuous treatment can be performed, and The inventors have found that a more uniform polyester resin powder can be obtained and completed the present invention.

  The first gist of the present invention is a method for producing a polyester resin powder in which a polyester resin powder is accommodated in a plurality of processing containers, and the polyester resin powder is brought into contact with a heated gas. (A) supplying a certain amount of polyester resin powder to the processing container; and (b) supplying heat gas to the processing container for a predetermined time to heat-treat the polyester resin powder. And (c) a step of discharging the treated polyester resin powder from the processing container, and the above steps are sequentially performed with a phase difference for each processing container. It exists in the manufacturing method of resin powder.

  In the present invention described in the first aspect, when the heat treatment of the polyester resin powder is performed, a heat treatment apparatus for the polyester resin powder is used, and the heat treatment apparatus has a powder filling port (2) at the top. And a plurality of processing vessels provided with a gas outlet (5), a powder outlet at the bottom and a gas inlet (4) at the bottom, and upstream of the powder filling port of these processing vessels And a powder supply mechanism (7) for switching and supplying resin powder to the powder filling ports, and arranged upstream of the gas inlets of the processing containers. A gas supply mechanism (8) for supplying a gas having a flow rate capable of bringing the resin powder in each processing vessel into a fluidized state, a heating mechanism (10) for heating the gas supplied from the gas supply mechanism, and the gas Gas supply port of each processing container from the supply mechanism It is preferable to include a flow rate control valve (9) disposed in each individual flow path, and a powder discharge valve (13) disposed on the downstream side of the powder discharge port of each processing container. .

Moreover, the 2nd summary of this invention is the process of manufacturing a polyester resin powder with the manufacturing method of the polyester resin powder as described in the said 1st summary, and pelletizing the obtained polyester resin powder. And a method for producing a polyester preform comprising a step of forming a polyester preform. According to the manufacturing method, since the preform is manufactured without manufacturing the resin pellet from the polyester resin powder, the manufacturing process can be simplified and a molded body such as a bottle can be manufactured.

Furthermore, a third aspect of the present invention is an apparatus for heat treatment of polyester resin powder, wherein the heat treatment apparatus is provided with a powder filling port and a gas discharge port at an upper portion and a powder discharge port at a lower portion. And a plurality of processing containers provided with gas inlets at the bottom, and a powder supply which is arranged upstream of the powder filling ports of these processing containers and which switches the resin powder to these powder filling ports And a gas supply mechanism that is disposed upstream of the gas inlets of the processing containers and supplies gas at a flow rate that can make the resin powder in the processing containers fluidized to the gas inlets. A heating mechanism for heating the gas supplied from the gas supply mechanism, a flow rate control valve disposed in an individual flow path from the gas supply mechanism to a gas inlet of each processing container, and each processing container On the downstream side of the powder outlet And a deployed powder discharge valve, the heat treatment temperature is at 20 ° C. or higher 250 ° C. or less, increment of intrinsic viscosity of the polyester resin powder by heat treatment, characterized in that at 0.20 dl / g or more Exists in the device.

  According to the present invention, the resin powder is switched and supplied to a plurality of processing containers, heat treatment is sequentially performed from the processing containers for which supply has been completed, the heat treatment is sequentially discharged from the processing containers, and these operations are performed. Since each processing container is sequentially executed with a phase difference, heat treatment using a fluidized bed can be performed substantially continuously, resin powder can be heat-treated more efficiently, and individual processing can be performed. Since the heat treatment itself is performed in a batch process in the container, the product quality can be further homogenized.

  The present invention is a method for producing a polyester resin powder. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a flow diagram showing a main configuration of an example of a heat treatment apparatus suitably used in carrying out a method for producing polyester resin powder by heat treatment of polyester resin powder according to the present invention. FIG. 2 is a flowchart showing an example of the configuration of a powder supply mechanism used in the heat treatment apparatus, and is a diagram of the powder supply mechanism including a plurality of three-way valves. FIG. 3 is a schematic perspective view showing another configuration example of the powder supply mechanism used in the heat treatment apparatus, and is a view of a powder distribution mechanism of a rotational distribution type. FIG. 4 is a flowchart showing the main configuration of another example of the heat treatment apparatus for resin powder according to the present invention, and is a diagram showing an embodiment in which two series of gas supply mechanisms are arranged. FIG. 5 is a process diagram showing each process of a heat treatment method using a heat treatment apparatus having five treatment containers. In the following description, a heat treatment apparatus for resin powder is abbreviated as “heat treatment apparatus”, and a method for producing polyester resin by heat treatment of polyester resin powder is abbreviated as “method for producing resin by heat treatment”.

  First, the heat processing apparatus used suitably by this invention is demonstrated. The said heat processing apparatus is a heat processing apparatus which contacts the gas heated with the resin powder, for example, is used suitably for the process of solid phase polymerization of resin. The heat treatment apparatus is configured by arranging a plurality of processing containers constituting a fluidized bed in parallel, and continuously supplying resin powder as a raw material by operating each processing container in a batch system and switching them sequentially. The processed resin powder as a product is continuously discharged.

  As shown in FIG. 1, the heat treatment apparatus has a powder filling port (2) and a gas discharge port (5) at the top, a powder discharge port (3) at the bottom, and a gas introduction port at the bottom. A plurality of processing containers (1) provided with (4) and disposed upstream of the powder filling port (2) of these processing containers (1), and resin powder with respect to these powder filling ports (2) The powder supply mechanism (7) for switching and supplying the body, and the upstream side of the gas inlet (4) of each processing container (1), each processing container (1) with respect to these gas inlets (4) A gas supply mechanism (8) for supplying a gas at a flow rate that can make the resin powder in a fluidized state, a heating mechanism (10) for heating the gas supplied from the gas supply mechanism, and a gas supply mechanism (8) Flow control valves (9) respectively disposed in individual flow paths from each to the gas inlet (4) of each processing vessel (1), Includes hairdressing apparatus (1) powder discharge port (3) a powder discharge valve which are disposed in the downstream side of the (13).

  The shape of the processing container (1) is not particularly limited, but the processing container (1) is usually formed in a columnar shape or a polygonal column shape, and is arranged so that the center line is vertical. Preferably, the processing container (1) is provided with a portion having a large horizontal sectional area at the top. That is, in the processing container (1), by gradually increasing the horizontal cross-sectional area from the middle of the body part to the upper part, the gas linear velocity can be lowered and the rising distance of the resin powder in the fluidized state can be reduced. I can do it. The height of the processing container (1) is not particularly limited, but is preferably about 3 to 5 times the stationary layer height of the supplied resin powder. Moreover, the inside of the processing container (1) may be divided into a plurality of processing spaces by providing a partition plate along the center line.

  Usually, the powder filling port (2) for supplying the resin powder is provided in the upper half part including the top part of the processing container (1), preferably in the upper part corresponding to 1/3 of the height including the top part, For example, it is provided on the top of the processing container (1). The powder discharge port (3) for discharging the processed resin powder as a product is a lower half portion including the bottom portion of the processing container (1), preferably a lower side corresponding to 1/3 of the height including the bottom portion. For example, it is provided on the side surface portion of the lower portion of the processing container (1). In general, the gas inlet (4) for supplying high-temperature gas is provided at the lowest part of the bottom of the processing vessel (1). The gas discharge port (5) for discharging the used gas is provided in the upper half part including the top part of the processing vessel (1), preferably in the upper part corresponding to 1/3 of the height including the top part. It is provided on the top surface or upper side surface of the processing container (1). In addition, a gas dispersion plate (6) having a porous structure for dispersing the supplied gas is disposed substantially horizontally inside the processing container (1). The gas dispersion plate (6) is preferably disposed immediately above the gas inlet (4) and directly below the powder outlet (3) as much as possible.

  The powder supply mechanism (7) is a mechanism for sequentially switching and supplying resin powder to each processing container (1). The powder supply mechanism (7) includes a plurality of processing containers from a single raw material supply line. Various mechanisms can be adopted as long as (1) has a structure capable of sequentially supplying the raw material powder. For example, as shown in FIG. 2, one or more three-way valves (71) are used. And a mechanism for selecting a supply destination of the resin powder. Such a powder supply mechanism (7) combines a number of three-way valves (71), which is one less than the number of processing containers (1) installed, and a predetermined processing container (1) by combining the switching operations of the flow paths. ) Can be supplied with resin powder.

  Further, as another example of the powder supply mechanism (7), as shown in FIG. 3, a substantially conical rotating member (72) in which a flow path is arranged from the top along the circumferential surface, It is also possible to use a rotation distribution type mechanism comprising receiving members (73) in which the flow paths are arranged in parallel by the number of processing containers (1) corresponding to the movement position of the tip of the flow path of the rotation member. The powder supply mechanism (7) selects the flow path of the receiving member (73) that communicates with the flow path of the rotating member by controlling the rotation of the rotating member (72), and transfers the resin to the predetermined processing container (1). It is designed to supply powder.

  The gas supply mechanism (8) shown in FIG. 1 is not particularly limited as long as the resin powder in the processing container (1) can be fluidized, but generally a general compressor or blower is used. In the heat treatment apparatus, a heating mechanism (10) is connected to the downstream side of the gas supply mechanism (8) in order to heat the gas as needed and supply it to each processing vessel (1). As the heating mechanism (10) for heating the gas, for example, a well-known plate-type or multi-tube heat exchanger or a gas heating furnace can be used.

  The flow rate control valve (9) introduces gas from the gas supply mechanism (8) to the gas introduction port (4) of each processing container (1), for example, gas from each processing container (1) through a common flow path. It arrange | positions at the branch flow path branched to the opening | mouth (4), respectively. The flow rate control valve (9) is not particularly limited as long as the flow rate of the gas supplied to each processing container (1) can be individually controlled independently, and typically the opening of an air operation valve or the like. An adjustable control valve is used, and the operation of such a valve is controlled by a control mechanism (not shown) described later. Specifically, by supplying the resin powder to the processing container (1) and discharging the resin powder from the processing container (1) by adjusting the opening of the flow control valve (9), the gas flow rate, That is, the gas flow rate in the processing vessel (1) can be reduced, and an operation can be performed to increase the gas flow rate, that is, the gas flow rate in the processing vessel (1) during the heat treatment.

  The powder discharge valve (13) is arranged on the downstream side of the powder discharge port (3) in order to take out the processed resin powder from the processing container (1). As the powder discharge valve (13), a control valve such as an electromagnetically operated valve or an air operated valve that can be controlled to open and close is used as a gate valve.

  Moreover, as shown in FIG. 1, in the said heat processing apparatus, in order to reduce gas consumption and also to effectively utilize the heat of high temperature gas and to reduce heating cost, the gas discharge port of each processing container (1) A gas circulation line (15) for returning the used gas discharged from (5) to the gas supply mechanism (8) may be provided. Reference numeral (14) denotes a gas discharge valve.

  Furthermore, it is preferable that a fine powder remover (11) is installed in the gas circulation line (15). A known cyclone, bag filter, or the like can be used as the fine powder remover (11). When the fine powder remover (11) is installed in the gas circulation line (15), the gas circulation line (15), each flow control valve (9), each gas dispersion plate (6), gas supply mechanism (8) ) And the like can be prevented, and the load on the impurity remover (12) described later can be reduced. Further, it is possible to remove the powder having a particle size less than the lower limit and prevent the product quality from being deteriorated. Moreover, by further selecting usable powder from the removed and recovered fine powder, mixing it with the raw material and returning it to the processing container (1), the yield of the raw material can be improved and the amount of waste generated can be reduced. .

  In addition, the above gas circulation is used to improve the reaction rate by improving the purity of the circulating gas to stabilize the product quality and removing water, diol components, ethylene glycol (EG), etc. in the circulating gas. The line (15) is preferably provided with an impurity remover (12) for removing water and / or organic impurities. Examples of water and / or organic impurities include water, EG, acetaldehyde, cyclic trimers, linear oligomers, and other low-boiling (low molecular weight) compounds contained in the raw resin, and water generated by polycondensation reaction. And low boiling point (low molecular weight) compounds such as EG and low boiling point (low molecular weight) compounds such as acetaldehyde by-produced by thermal decomposition of the resin. As the impurity remover (12), in addition to a gas burner, oxygen (air) is taken in according to the analysis value of the organic substance content, and an organic substance is oxidized by a catalyst or heat, or a wet or dry condenser or EG An example is a scrubber.

  Although not shown, in the heat treatment apparatus, the used gas discharged from the gas discharge port (5) of each processing vessel (1) is discharged out of the system without providing the gas circulation line (15). The gas supply mechanism (8) may always supply a new gas to the gas inlet. In that case, from the viewpoint of maintaining a good working environment and ensuring safety, the used gas is cleaned and discharged out of the system, so the downstream side of the gas discharge port (5) is as described above. A fine powder remover (11) is preferably installed, and an impurity remover (12) for removing water and / or organic impurities is preferably installed.

  Further, the heat treatment apparatus may be configured such that the temperature of the high-temperature gas supplied to the processing vessel (1) can be adjusted according to the progress of the processing such as solid phase polymerization, drying, and crystallization. That is, in another aspect of the present invention, a plurality of gas supply mechanisms are installed, and the gas temperatures of the respective systems are set to different temperatures according to the target temperature of the gas supplied to the processing container (1). These gases are mixed at an arbitrary ratio and supplied to each processing container (1).

  Specifically, as shown in FIG. 4, in addition to the above-described configuration, the heat treatment apparatus is arranged on the upstream side of the gas inlet (4) of each processing vessel (1) and is supplied by the gas supply mechanism (8). A second gas supply mechanism (8b) for supplying a gas having a temperature different from that of the gas to be supplied to each gas inlet (4), and the second gas supply mechanism to each gas inlet (4). And a second flow rate control valve (9b) disposed in each individual flow path.

  The heat treatment apparatus illustrated in FIG. 4 includes two series of gas supply mechanisms, that is, a gas supply mechanism (8) and a second gas supply mechanism (8b), and of course, further includes another gas supply mechanism. It may be. The code | symbol (10b) in FIG. 4 shows the 2nd heating mechanism similar to said heating mechanism (10). In the heat treatment apparatus as shown in FIG. 4, the temperature of the gas supplied to the treatment vessel (1) in the heat treatment step can be switched to, for example, three stages as described later, and a more homogeneous product can be obtained. I can do it. In the same heat treatment apparatus, three processes of crystallization, solid phase polymerization, and cooling can be performed.

  In the heat treatment apparatus, the operation of the powder supply mechanism (7), each flow control valve (9) and each powder discharge valve (13) can be controlled by a control mechanism (not shown) such as a process control computer. By such control, as will be described later, the supply of the resin powder, the heat treatment, and the discharge are sequentially performed with a phase difference for each processing container (1), and the operation is substantially substantially continuous as a whole. Therefore, the resin powder can be heat-treated more efficiently.

  That is, the control mechanism has a function of controlling the powder supply mechanism (7) so as to sequentially supply a predetermined amount of resin powder to the powder filling port (2) of each processing container (1); A function of controlling each flow rate control valve (9) so as to supply a heated gas to each processing container (1) sequentially after the resin powder is supplied for a certain period of time, and each processing container (1 sequentially after supplying the gas for a certain period of time. ) To control the respective powder discharge valves (13) to discharge the resin powder, and the powder supply mechanism (7), each flow control valve (9) and each powder discharge valve ( 13) has a function of sequentially executing the above control with a phase difference for each processing container (1).

  Further, in the heat treatment apparatus shown in FIG. 4, the second flow rate control valve (9b) is configured to be controllable by a control mechanism, and the control mechanism sequentially adds each processing container after the resin powder is supplied in addition to the above function. It has a function of controlling each flow rate control valve (9) and the second flow rate control valve (9b) so as to supply heated gas and / or gas of different temperature to (1). In the heat treatment apparatus shown in FIG. 4, the temperature of the gas supplied to each processing container (1) is controlled independently for each processing container (1).

  Next, the manufacturing method of the polyester resin powder of the present invention using the heat treatment apparatus will be described together with the function of the heat treatment apparatus. The method for producing polyester resin powder of the present invention is a method by heat treatment of polyester resin powder in which polyester resin powder is accommodated in a plurality of processing containers (1) and heated gas is brought into contact with the polyester resin powder. For example, it is suitably used for treatments such as drying, devolatilization and solid phase polymerization of polyester resins.

  In the present invention, polyester is used as the resin powder. In the following, solid phase polymerization of polyester will be described as an example, and any known polyester can be applied. For example, aromatic dicarboxylic acid such as terephthalic acid or dimethyl terephthalate or ester derivative thereof and diol component such as ethylene glycol And those obtained by melt polymerization of an esterified or transesterified product.

  The degree of polymerization of the polyester is not particularly limited, but considering that the degree of polymerization is increased by the heat treatment of the present invention, the intrinsic viscosity (IV) may be relatively low, and the intrinsic viscosity (IV) is Usually, polyesters in the range of 0.20 to 0.66 dl / g, preferably 0.25 to 0.60 dl / g, particularly preferably 0.27 to 0.55 dl / g are used. In the present invention, the increment of the intrinsic viscosity (IV) by heat treatment in the processing vessel (1) is usually 0.20 dl / g or more, preferably 0.25 dl / g or more, particularly preferably 0.28 or more. is there. When the increment of the intrinsic viscosity (IV) is in the above range, the productivity is improved by applying the present invention. The intrinsic viscosity (IV) is measured by dissolving the polyester resin powder in a phenol / tetrachloroethane mixed solvent (weight ratio 1/1) and using an Ubbelohde viscometer at 30 ° C.

  The weight average particle diameter of the polyester resin powder is usually 0.05 to 1.0 mm, preferably 0.08 to 0.50 mm, and particularly preferably 0.10 to 0.40 mm. If the particle size of the resin powder is too small, the ratio of the bed height between the fluidized state and the stationary state is large, and it is necessary to increase the height of the processing container (1). Moreover, the amount of powder discharged along with the gas discharge port (5) increases, and the yield may decrease. The particle size distribution of the polyester resin powder is preferably smaller. Specifically, the half width of the distribution when plotted with the weight frequency on the vertical axis and the particle diameter on the horizontal axis is usually twice or less, preferably 1.5 times or less of the weight average particle diameter. The particle size of the resin powder is measured at room temperature using a laser diffraction type particle size distribution measuring device by dispersing the resin powder in water to which a dispersant has been added.

  In the method for producing a polyester resin powder of the present invention in which the polyester resin powder is heat-treated, (a) a step of supplying a certain amount of polyester resin powder to the processing container (1), and (b) a processing container ( 1) repeating the process of supplying the heated gas for a certain period of time to heat-treat the polyester resin powder, and (c) discharging the processed resin powder from the processing container (1), The above steps are performed for each processing container (1) by controlling the operation of the powder supply mechanism (7), each flow control valve (9), and each powder discharge valve (13) by the above control mechanism. Hold it and execute it sequentially.

  The first step in the heat treatment is a step of supplying a certain amount of polyester resin powder to the processing vessel (1), and the polyester resin powder supplied through the raw material supply line is supplied to the powder supply mechanism (7). By switching control, the powder filling port (2) of each processing container (1) is sequentially distributed, and a certain amount of polyester resin powder is sequentially supplied to each processing container (1).

  The second step is a step of supplying the heated gas to the processing container (1) to heat-treat the polyester resin powder. Each gas heated to a constant temperature from the gas supply mechanism (8) is supplied at a constant flow rate. While supplying toward the gas inlet (4) of a processing container (1), gas is supplied to the processing container (1) which completed the 1st process by control of the flow control valve (9) of each processing container (1). To sequentially perform heat treatment.

  In the second step, the gas supply may be started after the polyester resin powder is completely filled into the processing container (1) or before the filling is completed, and the gas is supplied before the filling is completed. When starting to fill the polyester resin powder, reduce the gas linear velocity and gradually increase the flow rate as the polyester resin powder filling amount increases, or when the polyester resin powder filling is completed It is preferable to increase the flow rate.

  The gas linear velocity (superficial velocity) is not particularly limited as long as the fluidized state can be maintained and the polyester resin powder is not entrained and scattered, but is usually about 0.1 to 1.0 m / s. Usually, gas is blown upward from the vertically lower side of the gas dispersion plate (6), and the polyester resin powder is blown upward by the gas flow to be fluidized. At that time, the polyester resin powder is blown upward by the gas, and the motion of dropping downward by gravity occurs randomly, resulting in a completely mixed state. As the gas to be supplied, an inert gas, preferably nitrogen gas is usually used.

  The third step is a step of discharging the treated polyester resin powder from the processing container (1), and the powder discharge disposed on the downstream side of the powder discharge port (3) of each processing container (1). By opening the valve (13), the polyester resin powder is sequentially discharged from the processing container (1) that has completed the second step, and is used as a product in a subsequent post-processing step (not shown) for packaging and the like. The polyester resin powder is transferred.

  In the present invention, the above first to third steps are repeated for each processing container (1), and the above steps are sequentially executed with a phase difference for each processing container (1). That is, the process execution timing is shifted so that the filling and discharging processes do not overlap among the plurality of processing containers (1), and the series of processes is performed so that the idle time is minimized in each processing container (1). Run sequentially. As a result, the treatment by the fluidized bed can be performed substantially continuously as a whole system, the heat treatment time of the product can be made substantially constant, and the resin powder can be heat treated more efficiently.

  Specific examples of operations in the method for producing polyester resin powder by continuous heat treatment of the polyester resin powder using the heat treatment apparatus are further shown in the following table. The heat treatment illustrated in Table 1 uses three processing containers (1) of container 1, container 2 and container 3, and in one operation cycle, the resin powder as a raw material is taken for 1 hour. (Abbreviated as “filling” in the table), followed by heat treatment for 1 hour (abbreviated as “heat treatment” in the table), and discharging the product over an additional hour (“discharge” in the table) Abbreviated).

  When it is necessary to lengthen the heat treatment time as compared with the filling and discharging time of the polyester resin powder, it is preferable to increase the number of treatment containers (1). In order to lengthen the heat treatment time of the polyester resin powder, for example, five processing containers (1) are used, and the operation is performed with the operation phase shifted as shown in FIG.

  In addition, in the heat treatment according to a preferred embodiment of the present invention using the heat treatment apparatus shown in FIG. 4, in addition to the above-described operation control, the above-mentioned steps are performed by the operation control of each second flow rate control valve (9b). (1) Each phase is sequentially executed with a phase difference. In the heat treatment of the present invention, the temperature of the resin powder is controlled in three stages according to the progress of the reaction in the step of heat-treating the resin powder (the second step described above).

  That is, in the heat treatment of the present invention, in the heat treatment of the present invention, the gas temperature at the start of heat treatment is T1, the gas temperature during the heat treatment is T2, and the gas temperature at the end of the heat treatment is T3. The temperature of the gas supplied to each processing container (1) is adjusted so as to satisfy the following conditions. The temperatures T1, T2, and T3 are all gas temperatures at the inlet when introduced into the processing container (1).

  The gas temperature T1 at the start of the heat treatment is usually 120 to 220 ° C., preferably 160 to 210 ° C., particularly preferably 180 to 205 ° C., and the gas temperature T2 during the heat treatment is usually 180 to 250 ° C., preferably It is 190-245 degreeC, Most preferably, it is 200-240 degreeC, and temperature T3 of the gas at the time of completion | finish of heat processing is 20-220 degreeC normally, Preferably it is 120-210 degreeC, Most preferably, it is 180-205 degreeC. However, the above temperatures are adjusted so that T1 <T2 and T3 <T2.

  When switching from the temperature T1 at the start of the heat treatment to the temperature T2 during the heat treatment, it is preferable to gradually raise the temperature. As described above, for example, two series of gas supply mechanisms (8) and a second gas supply mechanism (8b) are installed, and the temperature of each series is set to a different temperature, depending on the target temperature. The gas from each series is mixed at an arbitrary ratio and supplied to each processing container (1). For example, the gas flow rate at temperature T1 is gradually reduced (or increased), and the gas flow rate at temperature T2 is gradually increased ( Or lower). Alternatively, it can be controlled by adjusting the output of the heating mechanism (10) while comparing the target gas temperature with the actual gas temperature.

  According to the method for producing polyester resin powder by heat treatment of the polyester resin powder of the present invention, the resin powder is treated with a plurality of processing containers (1 ) By the powder supply mechanism (7), sequentially supplied to each processing container (1), sequentially subjected to heat treatment from the processing container (1) for which supply has been completed, and from the processing container (1) for which heat treatment has been completed. In addition to the sequential discharge, these operations are sequentially performed with a phase difference for each processing vessel (1), so that the processing by the fluidized bed is performed substantially continuously and the heat treatment time is substantially constant as the entire system. It is possible to heat-treat the resin powder more efficiently and to further homogenize the product quality.

  Furthermore, according to the present invention, since a series of processing in each processing container (1) is sequentially performed at different timings for each processing container (1), compared with a conventional system that performs batch processing in a single processing container. In addition, it is possible to further downsize individual incidental facilities such as a piping system for supplying and discharging resin powder, and supplying gas, and a gas supply mechanism (8).

  A polyester resin preform can be produced without producing resin pellets by using the polyester resin powder obtained by the above-described method for producing polyester resin powder by heat treatment of polyester resin powder. As a method for obtaining a molded product such as a bottle using the polyester resin powder, a conventionally known molding method using pellets can be basically employed. As a known molding method, for example, there is a method in which heat treatment is performed at 110 ° C. to 190 ° C. for 2 to 24 hours in an inert gas atmosphere such as air or nitrogen, and then the mixture is supplied to a known molding machine and melt-molded. Can be mentioned. When the heat treatment temperature and time are within the above ranges, the polyester resin can be sufficiently dried, and the decrease in molecular weight and change in color tone during melt molding are further preferred.

  If the average particle size of the polyester resin is approximately 0.5 mm or less, use of a heat treatment device having a stirring function inside or a fluidized bed heat treatment device avoids sticking between particles (blocking). Since it can do, it is still more preferable.

  The polyester resin powder obtained by the heat treatment of the present invention can be formed into a bottle or the like by, for example, forming a preform by injection molding and then stretch-blow molding or blow-molding a parison molded by extrusion molding. Molded or formed into a sheet by extrusion molding, then formed into a tray or container by thermoforming, or biaxially stretched into a film or the like, particularly useful as a packaging material for food and drink It becomes a simple molded product. Among them, it can be suitably used for molding into a bottle by a blow molding method in which a preform obtained by injection molding is biaxially stretched. For example, liquid seasonings such as carbonated beverages, alcoholic beverages, soy sauce, sauces, mirin, and dressings In addition, it is preferably used as a container for beverages such as fruit juice drinks, vitamin drinks, flavor teas, mineral waters, etc., after heat setting.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

(A) Device:
An apparatus as shown in FIG. 1 is used. That is, four processing containers (1) are arranged in parallel, the processing container (1) has an inner diameter of 1 mφ, and a vertical distance from the upper surface of the gas dispersion plate (6) to the lower end of the gas discharge port (5) is 5 m. It is a cylindrical processing container.

(B) Raw material:
A spherical homopolyethylene terephthalate resin having an intrinsic viscosity of about 0.30 dl / g, a crystallinity of about 40%, and an average particle size of about 0.3 mm is used.

(C) Heat treatment method:
From the upstream process, the raw material is continuously supplied at a supply rate of 100 kg / hour.

  From the 0th hour to the 1st hour while flowing 200 ° C. nitrogen at a superficial linear velocity of 0.6 m / s in the first chamber (hereinafter referred to as “vessel 1”, etc.) of the processing vessel (1). The raw material is continuously filled for 1 hour at a supply rate of 100 kg / hour.

In the first hour, the powder supply mechanism (7) is switched and the filling destination is changed to the container 2. Hereinafter, the filling destination is switched in the order of container 3, container 4, container 1, container 2, and container 3 every hour. Hereinafter, although the implementation contents in the container 1 will be described, the implementation contents of the other containers are the same except that the phases are different.
In the container 1, the temperature of nitrogen to be supplied is increased from 200 ° C. to 230 ° C. at a rate of temperature increase of 10 ° C./min from the first hour to the first hour 30 minutes. During this time, the superficial linear velocity is 0.6 m / s.

  From 1 hour 30 minutes to 3 hours 30 minutes, heat treatment is performed while maintaining the temperature of the supplied nitrogen at 230 ° C. and the superficial linear velocity at 0.6 m / s.

  While the temperature of nitrogen supplied to the container 1 is lowered to 200 ° C. from 3 hours 30 minutes to 4 hours, the powder discharge valve (13) of the container 1 is opened and the product after the heat treatment is moved to the downstream process. Discharge. During this time, the superficial linear velocity in the container 1 is set to 0.3 m / s.

  After the discharge is completed, it is considered that the process has returned to the 0th hour, and the same process as described above is repeated.

  In this way, a polyethylene terephthalate resin having a viscosity suitable for melt molding is continuously obtained.

  In each of the above steps, the superficial linear velocity of nitrogen to be supplied may be changed intermittently. Moreover, a stirring blade may be provided in each processing container (1), or a fine powder remover such as a cyclone or a bag filter may be incorporated. In particular, when a bag filter is built in, it is preferable to use a filter having a heat resistance of 250 ° C. or higher, and it is particularly preferable to use a metal sintered metal filter. As the metal material, it is preferable to use stainless steel in terms of corrosion resistance and economy.

(D) Molding method:
After drying the polyethylene terephthalate resin obtained by the above heat treatment method at a temperature of 145 ° C. for 16 hours under a nitrogen atmosphere, the cylinder set temperature is 270 ° C. with an injection molding machine (ASB-50TH manufactured by Nissei Plastic Industrial Co., Ltd.) A preform, which is a molten molded body having a weight of about 33 g, is injection-molded under the conditions of a back pressure of about 1 MPa, an injection time of about 13 seconds, and a molding cycle of about 40 seconds. Next, using a stretch blow molding machine (manufactured by Mitsubishi Chemical Corporation), the resulting preform is blow-molded with a heating time of 75 seconds and molded into a 0.5 L bottle.

  In this way, a blow bottle suitable for beverage packaging and the like is obtained.

It is a flowchart which shows the main structures of an example of the heat processing apparatus of the resin powder used suitably for the manufacturing method of this invention. It is a flowchart which shows one structural example of the powder supply mechanism used for the heat processing apparatus. It is a typical perspective view which shows the other structural example of the powder supply mechanism used for the heat processing apparatus. It is a flowchart which shows the main structures of the other example of the heat processing apparatus of the resin powder used suitably for the manufacturing method of this invention. It is process drawing which shows each process of the heat processing method by the heat processing apparatus which has five processing containers.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Processing container 2: Powder filling port 3: Powder discharge port 4: Gas introduction port 5: Gas discharge port 6: Gas dispersion plate 7: Powder supply mechanism 8: Gas supply mechanism 8b: 2nd gas supply mechanism 9: Flow control valve 9b: Second flow control valve 10: Heating mechanism 10b: Second heating mechanism 11: Fine powder remover 12: Impurity remover 13: Powder discharge valve 14: Gas discharge valve 15: Gas circulation line

Claims (13)

Containing a polyester resin powder into a plurality of processing vessels, a process for making a polyester resin powder of heat-treating the polyester resin powder contacting the gas heated in the polyester resin powder, the manufacturing method (a) A step of supplying a certain amount of polyester resin powder to the processing container; (b) a step of supplying a heated gas to the processing container for a predetermined time to heat-treat the polyester resin powder; And repeating the step of discharging the treated polyester resin powder from the processing container, and sequentially performing the above steps with a phase difference for each processing container , by heat treatment in the processing container The increase in intrinsic viscosity of the polyester resin powder is 0.20 dl / g or more, and in the step (b) of heat-treating the polyester resin powder, the temperature of the gas at the start of heat treatment The T1, and characterized in adjusting if the temperature of the gas in the heat treatment T2, the temperature of the heat treatment at the end of the gas was set to T3, so as to satisfy the following conditions, the temperature of the gas supplied to the processing chamber To produce polyester resin powder.
  The method for producing a resin powder according to claim 1, wherein the heat treatment is a solid phase polymerization treatment of the polyester resin powder.   The method for producing a polyester resin powder according to claim 1 or 2, wherein the intrinsic viscosity of the polyester resin powder supplied to the treatment container is 0.20 to 0.66 dl / g. The method for producing a polyester resin powder according to any one of claims 1 to 3 , wherein the polyester resin powder has a weight average particle diameter of 0.03 to 1.5 mm. The method for producing a polyester resin powder according to any one of claims 1 to 4 , wherein an inert gas is supplied as a gas in the step of heat-treating the polyester resin powder. A polyester resin powder heat treatment apparatus is used for heat treatment of the polyester resin powder. The heat treatment apparatus is provided with a powder filling port (2) and a gas discharge port (5) at the upper part and a powder discharge port at the lower part. A plurality of processing containers provided with outlets and provided with gas introduction ports (4) at the bottom, and disposed upstream of the powder filling ports of these processing containers, and the resin powder is supplied to these powder filling ports A powder supply mechanism (7) to be switched and a flow rate that is arranged upstream of the gas inlets of the processing containers and can flow the resin powder in the processing containers into a fluidized state with respect to the gas inlets. A gas supply mechanism (8) for supplying the gas, a heating mechanism (10) for heating the gas supplied from the gas supply mechanism, and individual flows from the gas supply mechanism to the gas inlets of the processing containers. Flow control valve arranged in each path 9), the production of the polyester resin powder according to claim 1 and a powder outlet powder discharge valve which are disposed in the downstream side (13) of each processing chamber Method. The heat treatment apparatus includes a control mechanism that controls the operation of the powder supply mechanism, each flow control valve, and each powder discharge valve, and the control mechanism has a certain amount of resin powder with respect to the powder filling port of each processing container. A function of controlling the powder supply mechanism to sequentially supply the body, and a function of controlling each flow rate control valve to sequentially supply the heated gas to each of the processing containers for a predetermined time after the resin powder is supplied. And a function of controlling each powder discharge valve so as to sequentially discharge resin powder from each processing container after gas supply for a certain period of time, and the powder supply mechanism, each flow control valve and each powder discharge The manufacturing method of the polyester resin powder of Claim 6 which has the function to perform sequentially said control with respect to a valve for each said processing container to give a phase difference. A heat treatment apparatus is disposed on the upstream side of the gas introduction port of each processing container, and a second gas supply mechanism that supplies a gas having a temperature different from the gas supplied by the gas supply mechanism to each gas introduction port ( 8b) and a second flow rate control valve (9b) disposed in a separate flow path from the second gas supply mechanism to each of the gas inlets, and the second flow rate control valve Is configured to be controllable by the control mechanism, and the control mechanism sequentially supplies the heated gas and / or the gas at different temperatures to each processing container after the supply of the resin powder. The polyester resin according to claim 7 , having a function of controlling a second flow rate control valve, wherein the temperature of the gas supplied to each processing container is controlled independently for each processing container. Powder manufacturing method. The polyester according to any one of claims 6 to 8 , wherein the heat treatment apparatus is provided with a gas circulation line (15) for returning the gas discharged from the gas discharge port of each processing container to the gas supply mechanism. Manufacturing method of resin powder. The method for producing a polyester resin powder according to any one of claims 6 to 9 , wherein the heat treatment apparatus is one in which a fine powder remover (11) is installed on the downstream side of the gas discharge port or in the gas circulation line. The method for producing polyester resin powder according to any one of claims 6 to 10 , wherein a remover (12) for removing water and / or organic impurities is installed on the downstream side of the gas discharge port or on the gas circulation line. The process of manufacturing a polyester resin powder with the manufacturing method of the polyester resin powder in any one of Claims 1-11, and the process of shape | molding in the polyester preform, without forming the obtained polyester resin powder into resin pellets A method for producing a polyester preform comprising : An apparatus for heat treatment of polyester resin powder, wherein the heat treatment apparatus is provided with a powder filling port and a gas discharge port at the top, a powder discharge port at the bottom, and a gas introduction port at the bottom. A plurality of processing containers, a powder supply mechanism that is disposed upstream of the powder filling ports of these processing containers and that switches the resin powder to these powder filling ports, and a gas inlet of each of the processing containers A gas supply mechanism for supplying a gas having a flow rate capable of bringing the resin powder in each processing vessel into a fluidized state with respect to these gas inlets, and a gas supplied from the gas supply mechanism. A heating mechanism for heating, a flow rate control valve disposed in a separate flow path from the gas supply mechanism to the gas inlet of each processing container, and a downstream of the powder discharge port of each processing container, respectively With a powder discharge valve Cage, the heat treatment temperature is at 20 ° C. or higher 250 ° C. or less, device increments intrinsic viscosity of the polyester resin powder by heat treatment, characterized in that at 0.20 dl / g or more.