JPH0699439A - Continuous bridging method for extrusion molded body such as organic-peroxide compounded polymer - Google Patents

Abstract

PURPOSE:To develope a method for continuous bridging by imparting superheated steam and a microwave under the normal pressure in the continuous bridging of the extrusion molded body of polymer or rubber, wherein organic peroxide is compounded. CONSTITUTION:A microwave heating chamber 50 is made to be the no-oxygen state with overheated steam generated by heating saturated steam to a proper bridging temperature under the normal pressure. Thereafter, microwave processing and heating processing are performed for the extrusion molded body, wherein organic peroxide is compounded in the microwave heating chamber, and the extrusion molded body is bridged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polymers (for example, vinyl chloride, EVA chlorinated polyethylene, etc.) and rubbers (for example, NR, EPDM, N) containing an organic peroxide.
The present invention relates to a method for continuously cross-linking an extruded body of BR, CR, SBR, etc.), and particularly to a cross-linking method using microwaves.

[0002]

2. Description of the Related Art In a method of continuously cross-linking an extruded body of a polymer or a rubber containing an organic peroxide (Peroxide: hereinafter abbreviated as PO), a cross-linking method in which air intervenes is conventionally used, for example, It was not possible to use the hot air continuous vulcanization method or the microwave continuous vulcanization method under normal pressure. This is because the polymer radicals generated during cross-linking combine with oxygen in the air to cleave rubber molecules, which causes the surface of the PO formulation to become viscous. That is, the surface of the PO compound becomes sticky.

Therefore, at present, a cross-linking method using steam, an LCM method and the like are used. The former is usually 10-2
The PO compound is cross-linked by high-pressure steam of about 0 kg / cm ² , and the latter LCM method is a mixed salt that dissolves at high temperature (for example, 53 wt% potassium nitrate, 40 wt soda nitrite).
%, 7% by weight of sodium nitrate) to crosslink. According to these methods, the surface of the PO compound is not exposed to the air, so that the PO compound does not become viscous and the product is less likely to be oxidized and deteriorated.

[0004]

The above-mentioned conventional continuous cross-linking method is a cross-linking method under pressure, and therefore has a problem that uniform heating is difficult.

For example, when a thick PO compound or a highly foamed sponge product is cross-linked under pressure, the temperature rise in the central portion is inevitably delayed. Therefore, if an attempt is made to heat according to the temperature rise of the central portion, the surface will become too high in temperature. In particular, in the case of a PO formulation having a complicated profile, it becomes difficult to heat the whole uniformly.

In view of the above-mentioned circumstances, the present invention has developed a continuous cross-linking method for heating the surface under normal pressure, heating the inside by utilizing microwaves, and uniformly heating the inside and outside of the extrusion molded article for cross-linking. To aim.

[0007]

In order to achieve the above object, in the present invention, the inside of the microwave heating chamber is made oxygen-free by superheated steam generated by heating saturated steam to an appropriate crosslinking temperature, and microwave heating is performed. An extruded product of a polymer or a rubber compounded with an organic peroxide is continuously passed through the interior of the chamber, and microwave energy is irradiated during the passing, and extrusion molding is performed with the above-mentioned superheated steam and microwave energy. We propose a method for continuously cross-linking an extruded product such as a polymer containing an organic peroxide, which is characterized by cross-linking the body.

[0008]

According to the present invention, the microwave heating chamber is made oxygen-free by superheated steam generated by heating saturated steam of about 100 ° C. at normal pressure to an appropriate cross-linking temperature (about 130 ° C. to 230 ° C.). In the microwave heating chamber, a polymer or rubber molded body containing an organic peroxide is irradiated with microwaves to be crosslinked.

Since superheated steam has a large temperature difference between the saturation temperature and the heating temperature, it has a high energy retention and a high degree of superheat, and the above-mentioned molded body can be effectively heated to the crosslinking temperature. Then, since the microwave is simultaneously irradiated, the molded body generates heat from the inside, and the inner and outer surfaces are uniformly heated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 shows a crosslinking device for carrying out the continuous crosslinking method of the present invention.

This cross-linking device is an example for embodying the technical idea of the present invention, and the material, shape, structure and arrangement of the mechanical parts are not limited to the following structures. Various modifications can be made within the scope of the claims of the present invention.

In the figure, reference numeral 50 denotes a microwave heating chamber having a heat insulating structure, and openings 51 and 52 provided with measures against microwave leakage are provided on the left and right sides.
A conveyance belt 54, which is connected to the motors 1, 52 and is driven by the motor 53, crosses the inside of the microwave heating chamber 50.

A return duct 55 is provided above the microwave heating chamber 50, and an air supply duct 5 is provided below the heating chamber 50.
6 are provided so as to communicate with the heating chamber 50.
Similar to the microwave heating chamber 50, the return duct 55 and the air supply duct 56 also have a heat insulating structure.

The return duct 55 and the air supply duct 5 are also provided.
6 and 6 are respectively connected to a heat exchanger type heating heater 57, of which the return duct 55 is connected via a heat resistant circulation fan 58. That is, the microwave heating chamber 5 described above
0, the return duct 55, the heating heater 57, and the air supply duct 56 form a circulation path for superheated steam described later.

The above-mentioned superheated steam is produced as follows. Steam (saturated steam) having a temperature of about 100 ° C. is generated by a steam generator (not shown), and this steam is taken into the return duct 55 from a steam supply adjusting valve 59 provided in the return duct 55. This steam is a heat-resistant circulation fan 58
Is taken into the heat exchanger type heating heater 57 by this heating heater 57 and the predetermined cross-linking temperature is 130 ° C. to 23 ° C.
The temperature is raised to 0 ° C.

At this time, the temperature atmosphere in the heating heater 57 is adjusted by the detection signal of the temperature sensor 60 provided near the outlet of the heating heater 57.

The above-mentioned heating heater 57 generates high-temperature air by a combustion device (not shown). This combustion device uses fuel oil such as heavy oil, kerosene and LPG as a combustion burner. -Ignite and burn. The configuration is not limited to this, and it may be configured by an electric heater.

The superheated steam thus produced is
Saturation temperature (about 100 ℃) and superheat temperature (about 130 ℃ ~ 23
Since the temperature difference (0 ° C.) is large, the amount of energy held is high and the degree of heating is large. Then, this superheated steam is sent to the microwave heating chamber 50 through the air supply duct 56.

The microwave heating chamber 50 is partitioned by a blowout shield plate 61 provided inside the chamber, and the superheated steam is blown out by the blowout holes 61a, 61b, 61c.
It is blown out more vigorously.

The heated steam thus entering the microwave heating chamber 50 passes through the return duct 55, is sucked by the heat-resistant circulation fan 58, and returns to the heating heater 57 again.

The return duct 55 is provided with a return adjusting valve 62 for adjusting the amount of return air, and the microwave heating chamber 50 is provided with an exhaust adjusting valve for adjusting superheated steam in the heating chamber 50. 63 are provided.

On the other hand, the microwave is oscillated by the microwave oscillator 64 and emitted from the irradiation opening at the tip of the waveguide 65. The irradiation port is provided with a seal plate 66 made of a material such as Teflon, ceramic, and quartz glass.
Prevents the entry of superheated steam.

Next, the procedure for carrying out the continuous crosslinking method of the present invention will be described. Before the polymer or rubber molding 67 containing an organic peroxide (PO) is cross-linked, the steam supply adjusting valve 59 and the exhaust adjusting valve 63 are closed, and the heat-resistant circulation fan 58 and the heating heater 57 are connected. The microwave heating chamber 50, the return duct 55, which is a circulation path, is operated for a predetermined time.
The temperature inside each of the heating heater 57 and the air supply duct 56 is raised. This is to prevent heat from being taken away and water droplets being generated when high-temperature superheated steam enters the low-temperature interior.

After that, while the steam supply adjusting valve 59 and the exhaust adjusting valve 63 are opened and the return adjusting valve 62 is closed, saturated steam at about 100 ° C. is supplied into the return duct 55 from the steam supply adjusting valve 59. To do.

The saturated steam is sucked into the heat-resistant circulating fan 58 and enters the heating heater 57, and is heated to the cross-linking temperature by the heating heater 57 to become superheated steam of about 130 to 230 ° C. The microwave 56 enters the microwave heating chamber 50.

At this time, the return adjusting valve 62 provided in the return path of the superheated steam is closed, and the superheated steam filled in the microwave heating chamber 50 is left and right between the exhaust adjusting valve 63 and the microwave heating chamber 50. Is discharged outward from the openings 51, 52 of the.

This release of superheated steam is accompanied by air, and if this state is continued for a certain period of time, the air concentration in the microwave heating chamber 50 becomes thin and the inside of the microwave heating chamber 50 becomes anoxic. Further, since the above-mentioned superheated steam is generated by heating saturated steam at normal pressure under normal pressure, the inside of the microwave heating chamber 50 is in an anoxic state even under normal pressure.

In this state, when the exhaust control valve 63 is closed in the closing direction and the return control valve 62 is opened, the superheated steam is sucked by the heat resistant circulation fan 58 and the heating heater 5 is heated.
Return to 7.

In addition to the above-mentioned superheated steam, saturated steam supplied from the steam supply adjusting valve 59 is taken into the heating heater 57, and the heating heater 57 raises the steam again to the crosslinking temperature. . After that, saturated steam is added to the microwave heating chamber 50, the increased amount of superheated steam is sent, and this circulation is repeated.

Such superheated steam circulation keeps the inside of the microwave heating chamber 50 at normal pressure. That is, since the saturated steam is constantly added, the saturated steam is pressurized by the amount of the saturated steam, and the left and right openings 51, 5 of the microwave heating chamber 50 are pressurized.
2 and the exhaust control valve 63 release superheated steam, and as a result, the microwave heating chamber 50 maintains an anoxic state under normal pressure.

After the inside of the microwave heating chamber 50 is made oxygen-free in this way, the molded body 67 as a PO compound is passed through the inside of the microwave heating chamber 50 while being conveyed by the conveyor belt 54. Is irradiated with microwaves.

The molded body 67, which has received microwave energy and superheated steam heated to the crosslinking temperature in the microwave heating chamber 50, undergoes molecular vibration to internally generate heat, and its inner and outer surfaces are uniformly heated. It is discharged from the microwave heating chamber 50 as 67. Further, the discharged molded body 67 is immediately cooled in the cooling step to become a product.

The malodorous gas generated from the microwave heating chamber 50 is burned and treated by a deodorizing device (not shown) provided in this device.

The description of the present embodiment describes the basic concept of the continuous cross-linking method, and when the cross-linking conditions are different, for example, when the moving speed of the molded body 67 is limited,
It is possible to continuously install a plurality of the above-mentioned crosslinking devices, and it is also possible that the irradiation of microwaves and the temperature increase by superheated steam are performed by different devices.

[0035]

As described above, according to the continuous crosslinking method of the present invention, the inside of the microwave heating chamber is kept in an oxygen-free state at atmospheric pressure, and thereafter, in this microwave heating chamber, an extrusion molded body as a PO compound is formed. Microwave treatment and heat treatment,
Since the method for crosslinking the extruded product is used, it is possible to perform crosslinking by using microwaves under normal pressure, which has not been possible in the past as a method for crosslinking PO compounds. The sponge products and the like can be easily crosslinked.

Further, the pressure seal required for the cross-linking under pressure is not required, which is advantageous in terms of cost. Furthermore, the microwave heating chamber in an oxygen-free atmosphere is safe without danger of ignition or fire.

[Brief description of drawings]

FIG. 1 is a simplified side view showing a crosslinking device for carrying out the continuous crosslinking method of the present invention.

[Explanation of symbols]

 50 Microwave heating chamber 51, 52 Opening 53 Motor 54 Conveyor belt 57 Heat exchange type heating heater 58 Heat resistant circulation fan 64 Microwave oscillator 65 Waveguide 67 Extrusion molded body

Claims (1)

[Claims] 1. A superheated steam generated by heating saturated steam to an appropriate crosslinking temperature makes the inside of the microwave heating chamber free of oxygen, and the inside of the microwave heating chamber is filled with a polymer or rubber containing an organic peroxide. An organic peroxide-blended polymer characterized in that the extruded product is continuously passed through, and microwave energy is applied during the passage to crosslink the extruded product with the superheated steam and the microwave energy. Extruded body continuous crosslinking method such as.