JP2006335998A - Method for continuously polymerizing resin in solid phase by high-frequency heating and apparatus for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus capable of improving treatment efficiency in recycling treatment of PET bottles by solid-phase polymerization. <P>SOLUTION: This apparatus is equipped with a hermetically sealed treatment housing 1 for holding a nitrogen gas atmosphere in its inside, a first belt conveyor 2 for introducing a resin material M to be polymerized in a solid phase into the treatment housing, then conveying the material by passing the material through the treatment housing, and further discharging the material from the treatment housing, a first high-frequency generating means 4 for applying high-frequency waves to a reaction zone 3 arranged on a midway of a conveying route of the resin material in the treatment housing, a first temperature sensor 6 for detecting a temperature of the reaction zone in the treatment housing, and a first control means 5 for controlling action of the first high-frequency generating means based on a detected signal from the first temperature sensor and making the resin material polymerized in the solid state by high-frequency heating in the reaction zone. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for performing continuous solid phase polymerization of a resin using high-frequency heating.

In recent years, resource recycling has been actively performed from the viewpoint of environmental protection. For example, used PET bottles are collected and reused.
Conventionally, the PET bottles have been recycled by pulverizing, washing, drying, heating and melting the collected PET bottles, and then producing a recycled product using the pellets as raw materials.

In manufacturing a recycled product, it is very advantageous in terms of cost to use injection molding using recycled pet pellets obtained from a pulverized product of a PET bottle. However, recycled pet pellets have lower molecular weight (degree of polymerization) and intrinsic viscosity (IV value) than virgin pets.
For this reason, when manufacturing a recycled product by injection molding, it is difficult to obtain appropriate molding conditions, and even if injection molding is performed, there is a problem that product strength is low and commercial value is low. .

  In order to solve this problem, a method has been proposed in which a pulverized product of a PET bottle is dried, heated to a polymerization temperature, and solid-phase polymerized to increase the degree of polymerization (molecular weight) and reproduce pellets ( (See Patent Documents 1 and 2).

However, in this conventional solid phase polymerization method, the heating up to the polymerization temperature of the pulverized product of the PET bottle is performed using a heat transfer heating means, so that the heating efficiency is poor, and therefore the solid phase polymerization reaction takes a long time. There was a problem of needing.
JP 2002-11719 A JP 2002-37915 A

  Accordingly, an object of the present invention is to improve the processing efficiency in the recycling process of PET bottles by solid phase polymerization.

  In order to solve the above-mentioned problem, the first invention is a method in which a resin material is continuously introduced into an inert gas atmosphere or a vacuum atmosphere, and the resin material is heated to a polymerization temperature by high frequency in the atmosphere. After the polymerization, the resin is discharged from the atmosphere to constitute a continuous solid phase polymerization method of resin.

In the configuration of the first invention, it is preferable that the resin material is crystallized and dehumidified and dried before being introduced into the inert gas atmosphere or the vacuum atmosphere.
The resin material is preferably crystallized and dehumidified and dried by high-frequency heating, and the inert gas atmosphere is preferably a nitrogen gas atmosphere.

  In order to solve the above-mentioned problems, a second invention provides a sealed processing housing having an inlet and an outlet and maintaining an inert gas atmosphere or a vacuum atmosphere therein, and a resin material to be solid-phase polymerized. A first conveying means that is introduced from the inlet of the processing chamber, passes through the processing housing and is transported, and then is discharged from the outlet of the processing housing, and a reaction provided in the middle of the transport path of the resin material in the processing housing A first high frequency generating means for applying a high frequency to the region, a first temperature sensor for detecting a temperature of a reaction region in the processing housing, and a detection signal from the first temperature sensor; First control means for controlling the operation so that the resin material is solid-phase polymerized by high-frequency heating in the reaction region. It is obtained by constituting the continuous solid-phase polymerization apparatus of the resin and symptoms.

In the configuration of the second invention, preferably, the apparatus further includes a purification apparatus containing an adsorption or absorption material capable of removing gaseous monomers and oligomers generated in the reaction region in the processing housing.
Preferably, the apparatus further includes a drying device that crystallizes and dehumidifies and drys the resin material to be solid-phase polymerized before being introduced into the processing housing, and the drying device includes a drying device having an inlet and an outlet. The housing and the resin material are introduced from the inlet of the drying housing, transported through the drying housing, discharged from the outlet of the drying housing, and transferred to the first transporting means. A second high frequency generating means for applying a high frequency to a drying area provided in the middle of the transport path of the resin material in the drying housing, and a second temperature sensor for detecting the temperature of the drying area in the drying housing; A second control means for controlling the operation of the second high-frequency generating means based on a detection signal from the second temperature sensor; Includes a dry air supply means for supplying air, the.
Moreover, it is preferable that the said 1st and 2nd conveyance means consists of a belt conveyor.

According to the present invention, the resin material is heated by high-frequency heating instead of conventional heat transfer heating. That is, the resin material is not supplied with heat energy from the outside, but generates heat from the inside due to a heat generation phenomenon caused by a high-frequency electromagnetic field. Therefore, the resin material is heated extremely efficiently and uniformly, and thus, it is possible to perform solid phase polymerization of the resin material in a shorter time than before.
Needless to say, according to the present invention, not only can the degree of polymerization (molecular weight) of recycled pellets be increased, but also the degree of polymerization (molecular weight) of virgin pellets such as polyester and polyamide can be increased.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram schematically showing the configuration of a continuous solid phase polymerization apparatus for resin according to one embodiment of the present invention. Referring to FIG. 1, according to the present invention, a sealed processing housing 1 having an inlet 1a and an outlet 1b, and holding an inert gas atmosphere or a vacuum atmosphere, in this embodiment a nitrogen gas atmosphere, A resin material M to be solid-phase polymerized is introduced from the inlet 1 a of the processing housing 1, transported through the processing housing 1, and then discharged from the outlet 1 b of the processing housing 1.

A reaction region 3 is provided in the middle of the transport path of the resin material M in the processing housing 1, and first high frequency generating means 4 for applying a high frequency to the reaction region 3 is provided. The first high-frequency generating means 4 is composed of, for example, a pair of high-frequency parallel electrode plates that are spaced apart from each other across the conveyance surface of the first belt conveyor, and a high-frequency power source connected to these electrode plates. Is done.

In addition, a first temperature sensor 6 for detecting the temperature of the reaction region 3 is provided in the processing housing 1, and the operation of the first high frequency generating means 4 is controlled based on a detection signal from the first temperature sensor 9. In addition, first control means 5 is provided for allowing the resin material M to undergo solid phase polymerization by high frequency heating in the reaction region.

  Furthermore, a purification device 7 is provided which contains an adsorption or absorption material capable of removing gaseous monomers and oligomers generated in the reaction region in the processing housing 1. Thus, the nitrogen gas in the processing housing 1 is constantly circulated through the purifier 7 and purified.

On the upstream side of the processing housing 1, as a pretreatment, a drying device that crystallizes the resin material M to be solid-phase polymerized in advance and dehumidifies it is provided. The drying apparatus 8 includes a drying housing 8 having an inlet 8a and an outlet 8b, and a resin material M introduced from the inlet 8a of the drying housing 8, transported through the drying housing 8, and then the outlet 8b of the drying housing 8. The second belt conveyor 9 is provided to be discharged from the first belt conveyor 2 and delivered to the first belt conveyor 2.

The drying apparatus further includes second high frequency generating means 11 that applies a high frequency to the drying region 10 provided in the middle of the transport path of the resin material M in the drying housing 8, and the temperature of the drying region 10 in the drying housing 8. The second temperature sensor 13 to be detected, the second control means 12 for controlling the operation of the second high frequency generation means 11 based on the detection signal from the second temperature sensor 13, and the drying for supplying dry air into the drying housing 8 Air supply means 14.

  Thus, the resin material M to be solid-phase polymerized is continuously introduced into the drying housing 8 from the inlet 8 a of the drying housing 8 via the second belt conveyor 9. Thereafter, while passing through the drying region 10, the resin material M is crystallized by high-frequency heating in a dry air atmosphere in the drying housing 8 and dehumidified and dried. The resin material M that has been crystallized and dehumidified and dried is sequentially discharged from the outlet 8 b of the drying housing 8 via the second belt conveyor 9 and is transferred to the first belt conveyor 2.

  Next, the crystallized, dehumidified and dried resin material M is sequentially introduced into the processing housing 1 from the inlet 1 a of the processing housing 1 via the first belt conveyor 2. Then, while passing through the reaction region 3, the resin material M is heated to the polymerization temperature by high-frequency heating in a nitrogen gas atmosphere and is solid-phase polymerized. The solid-phase polymerized resin material M is discharged from the outlet 1 b of the processing housing 1 by the first belt conveyor 2.

1 is a block diagram schematically showing a configuration of a continuous solid-phase polymerization apparatus for a resin according to one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing housing 1a Inlet 1b Outlet 2 1st belt conveyor 3 Reaction area | region 4 1st high frequency generation means 5 1st control means 6 1st temperature sensor 7 Purification apparatus 8 Drying housing 8a Inlet 8b Outlet 9 2nd belt conveyor 10 Drying area 11 Second high frequency generation means 12 Second control means 13 Second temperature sensor 14 Dry air supply source M Resin material

Claims (8)

A resin material is continuously introduced into an inert gas atmosphere or a vacuum atmosphere, and the resin material is heated to a polymerization temperature by high frequency in the atmosphere, solid-phase polymerized, and then discharged from the atmosphere. A continuous solid-state polymerization method for resins characterized by the following. 2. The continuous solid-state polymerization method for a resin according to claim 1, wherein the resin material is crystallized and dehumidified and dried before being introduced into the inert gas atmosphere or the vacuum atmosphere. 3. The resin solid-state polymerization method according to claim 2, wherein the resin material is crystallized and dehumidified and dried by high-frequency heating. The continuous solid-state polymerization method for a resin according to any one of claims 1 to 3, wherein the inert gas atmosphere is a nitrogen gas atmosphere. A hermetically sealed processing housing having an inlet and an outlet and maintaining an inert gas or vacuum atmosphere therein;
A resin material to be solid-phase polymerized is introduced from the inlet of the processing housing, passed through the processing housing and transported, and then discharged from the outlet of the processing housing;
First high frequency generating means for applying a high frequency to a reaction region provided in the middle of the transport path of the resin material in the processing housing;
A first temperature sensor for detecting a temperature of a reaction region in the processing housing;
First control means for controlling the operation of the first high-frequency generating means based on a detection signal from the first temperature sensor so that the resin material undergoes solid-phase polymerization by high-frequency heating in the reaction region. An apparatus for continuous solid-phase polymerization of resin. 6. The continuous solid phase of resin according to claim 5, further comprising a purification device containing an adsorption or absorption material capable of removing gaseous monomers and oligomers generated in a reaction region in the processing housing. Polymerization equipment. The resin material to be solid-phase polymerized further comprises a drying device for crystallizing and dehumidifying and drying before introduction into the processing housing,
A drying housing with an inlet and an outlet;
The resin material is introduced from the inlet of the drying housing, passed through the drying housing and conveyed, then discharged from the outlet of the drying housing, and transferred to the first conveying means;
Second high frequency generating means for applying a high frequency to a drying region provided in the middle of the transport path of the resin material in the drying housing;
A second temperature sensor for detecting the temperature of the drying area in the drying housing;
Second control means for controlling the operation of the second high frequency generation means based on a detection signal from the second temperature sensor;
The apparatus for continuous solid phase polymerization of resin according to claim 5, further comprising dry air supply means for supplying dry air into the dry housing. The continuous solid phase polymerization apparatus for resin according to any one of claims 5 to 7, wherein the first and second transport means are belt conveyors.

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