JP3051484B2 - Method for producing pyrolytic wax - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermally decomposed wax, and more particularly to a method for thermally decomposing an olefin polymer to obtain a thermally decomposed wax having a high degree of decomposition by a simple apparatus and process. The present invention relates to a method capable of continuously and stably performing a pyrolysis reaction over a long period of time and obtaining a high-quality product pyrolyzed wax.

[0002]

2. Description of the Related Art Conventionally, low molecular weight polymers, for example, polyolefins such as low molecular weight polyethylene and polypropylene, are used as waxes as pigment dispersants, rubber processing aids, resin processing aids, additives for inks or paints, and fibers. Used for a wide range of applications such as processing agents and toner for electrostatic copying,
The demand for wax in these applications in recent years has tended to increase, and the demands for higher quality have become more stringent. The low molecular weight polymer used as the wax varies depending on the raw material polymer, the use of the wax, and the like, but usually has an intrinsic viscosity [η] (135 ° C, decalin solution) of 0.05 to 0.4.
(Viscosity average molecular weight: about 1,000 to 25,000).

As a method for obtaining a wax comprising a low-molecular-weight polyolefin, a method by telomerization of an olefin, a method of thermally decomposing a high-molecular-weight polymer, and separation and purification of a low-molecular-weight polymer by-produced in the production of a high-molecular-weight polymer. There are ways to do that.

Various methods using an extruder have been proposed as a method for reducing the molecular weight of a high molecular weight polymer by thermal decomposition or the like (Japanese Patent Publication Nos. 39-14509 and 40).
-12376, 47-26388, 5
JP-A-1-48196, JP-A-59-28207, JP-A-61-190510, JP-A-61-108609.
No.).

[0005]

However, the conventional method using these extruders involves heating the high-molecular-weight polymer as a raw material, simultaneously using the shearing force of the extruder, and thermally decomposing peroxides and the like. This is a method in which a reaction accelerator is used in combination, and can only thermally decompose a high molecular weight polymer as a raw material slightly, and it is difficult to obtain a polymer having a desired degree of thermal decomposition.

Here, the degree of thermal decomposition in the thermal decomposition reaction is evaluated by the difference between the average molecular weight of the raw material polymer before thermal decomposition and the average molecular weight of the product after thermal decomposition. As an index representing the average molecular weight, usually, melt viscosity, intrinsic viscosity, M
FR (melt flow rate) and the like are commonly used because measurement is easy. Therefore, the degree of thermal decomposition can be represented by the ratio of these index values (index value of product / index value of raw material polymer).

Considering the degree of thermal decomposition achieved by the above-mentioned conventional method, the thermal decomposition degree in the conventional method is 1: 3 to 5 as a ratio of melt viscosity and as a ratio of MFR. The ratio was about 2: 1, and the intrinsic viscosity of the obtained product was only about 0.9, and a low-molecular-weight wax having a sufficient degree of decomposition as a wax was not obtained. Also,
When a thermal decomposition reaction accelerator such as a peroxide is used in combination, the obtained thermal decomposition wax may be colored or smelled to cause deterioration in quality.

Further, when a large pyrolysis reactor is generally used to obtain a wax having a high degree of decomposition, the mixing state of the reaction mixture in the reactor becomes uneven and the heat transfer state deteriorates. The heating temperature of the reactor must be high. Thus, when the heating temperature of the reactor is increased, a thermally degraded product of the reaction mixture is generated on the inner surface of the reactor,
In order to reduce the product quality, it is necessary to stop the operation and clean the inside of the reactor, and it has been difficult to stably produce the pyrolytic wax for a long period of time.

Accordingly, an object of the present invention is to provide a method for thermally decomposing an olefin polymer by a thermal decomposition reaction only by heating without using a thermal decomposition accelerator such as a peroxide by a simple apparatus and process. It is an object of the present invention to provide a method capable of continuously and stably obtaining a pyrolysis wax having a high degree of decomposition and a high quality over a long period of time.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for producing a pyrolysis wax having a high degree of decomposition by supplying an olefin polymer to a pyrolysis apparatus and causing a pyrolysis reaction. Wherein the thermal decomposition apparatus is constituted by connecting a plurality of thermal decomposition reactors each comprising a quantitative transfer means for quantitatively transferring the reaction mixture and a screw-type extruder connected to the quantitative transfer means. It is intended to provide a method for producing a thermally decomposed wax. .

Hereinafter, the method for producing the pyrolytic wax of the present invention will be described in detail.

Examples of the olefin polymer as a starting material in the method of the present invention include a homopolymer of an α-olefin, a copolymer of at least two or more α-olefins, or an α-olefin and the α-olefin. Copolymers of olefin with other monomers copolymerizable with olefin are exemplified.

Examples of the α-olefin include ethylene, propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, and 3-methyl- 1-pentene, 4-
Methyl-1-pentene, 1-heptene, 1-octene,
Examples thereof include 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-icosene.

Other monomers copolymerizable with these α-olefins include, for example, acrylic acid, methacrylic acid, acrylate, methacrylate, and the like.
Examples include polybasic unsaturated carboxylic acids such as vinyl acetate and maleic acid, and anhydrides thereof, and esters thereof. These may be used alone or in combination of two or more.

[0015] The method of the present invention comprises a plurality of pyrolysis reactors comprising these olefin-based polymers connected in series with a quantitative transfer means and a screw-type extruder connected to the quantitative transfer means. This is a method for producing a pyrolyzed wax by supplying it to a pyrolysis apparatus and pyrolyzing it.

Hereinafter, as one embodiment of the present invention, a pyrolysis reaction apparatus in which two pyrolysis reactors are connected in series will be taken as an example.
The method of the present invention will be described.

The pyrolysis apparatus shown in FIG. 1 comprises a first pyrolysis reactor 1 and a second-stage pyrolysis reactor 2 connected to the first pyrolysis reactor 1. The first thermal decomposition reactor 1 is composed of a quantitative transfer means 1a and a screw type extruder 1b connected to the quantitative transfer means 1a. The second-stage pyrolysis reactor 2 includes a quantitative transfer means 2a and a screw-type extruder 2 connected to the quantitative transfer means 2a.
b.

In the thermal decomposition apparatus shown in FIG. 1, an olefin polymer as a starting material is introduced from a raw material introduction path 3 and the screw type extruder 1b is driven by a quantitative transfer means 1a of a first stage thermal decomposition reactor 1. At a constant flow rate.
By precisely controlling the transfer amount of the raw material to the screw type extruder 1b by the quantitative transfer means 1a, the residence time of the reaction mixture in the screw type extruder 1b, that is, the pyrolysis reaction time can be accurately controlled. it can.

Specific examples of the quantitative transfer means 1a include:
Examples include a screw pump and a gear pump, which are appropriately selected according to the supply amount of the raw material olefin polymer, the viscosity of the raw material, the accuracy of the required supply amount, the heating temperature and the pressure for supplying the raw material, and the like. In particular, a gear pump is preferable because the raw material having a high viscosity can sufficiently transfer the raw material to the screw-type extruder, and is excellent in the accuracy of the supply amount and the boosting performance.

The olefin polymer supplied to the screw type extruder 1b undergoes a predetermined thermal decomposition reaction while being kneaded by a screw.

In the screw type extruder 1b,
While the reaction mixture is kneaded with a screw, the rotating screw scrapes off a scale including a thermally degraded product of the reaction mixture attached to the inner surface of the screw type extruder 1b (for example, the inner surface of the extruder barrel or the surface of the screw), These scales can be prevented from adhering to the inner surface of the screw type extruder 1b.

The screw type extruder 1b may have any one of a single screw and a multi-screw having two or more screws, and is not particularly limited. In addition, examples of the shape of the screw include a single thread type, a double thread type, and a triple thread type. In the case of a multi-screw having two or more shafts, any of a meshing type and a non-meshing type may be used.
In the method of the present invention, it may be appropriately selected according to a desired degree of thermal decomposition, generation of a thermally degraded product due to the thermal decomposition reaction, and the degree of adhesion of the thermally degraded product to the inner surface of the extruder. In particular, a biaxial meshing type screw in which the screws slide with each other is preferable in that the pyrolysis time can be lengthened and the self-cleaning property of preventing the adhesion of scale due to the rotation of the screw becomes good. In particular, a twin-screw extruder having a single or double screw type screw and a meshing type screw is preferable.

This screw-type extruder has a screw outer diameter D of about 30 to 400 mm, and a screw length L and a ratio (L / D) of D of about 20 to 60, which is highly thermally decomposed. It is suitable for obtaining a degree of pyrolysis wax. Further, the groove depth (h) of the screw is preferably a deep groove in order to obtain a thermally decomposed wax having a high degree of thermal decomposition, and usually a screw having an h / D of about 0.08 to 0.25 is suitable. is there. Furthermore, in controlling the residence time of the reaction mixture in the extruder to produce a high-decomposition pyrolytic wax, and in controlling the pressure in the extruder to separate volatile components by-produced in the pyrolysis reaction from the reaction mixture. It is effective to use a screw partially provided with a portion having a different shape such as a reverse screw shape. The difference between the screw outer diameter and the barrel inner diameter of the extruder is that self-cleaning is good,
It is preferably about 0.05 to 0.15 mm.

The screw-type extruder 1b has a vent portion 4 of the screw-type extruder 1b for separating and discharging volatile components by-produced by the thermal decomposition reaction. May be provided.

The material of the above screw type extruder is not particularly limited, and may be appropriately selected from those commonly used for this type of extruder.

The heating temperature of the first stage pyrolysis reactor 1 in the screw type extruder 1b is usually 300 to 450 ° C.
The residence time of the reaction mixture in the screw type extruder 1b, that is, the thermal decomposition reaction time is controlled to about 2 to 15 minutes. The number of rotations of the screw in the screw-type extruder 1b is usually 10 to 100 rpm because the self-cleaning property inside the extruder by the rotation of the screw is good and the heat transfer state can be improved.
It is about. Further, the rotation direction of the screw is not particularly limited, and in the twin-screw extruder, each axis may be rotated in the same direction or in different directions.

The heating of the screw type extruder is preferably carried out by a casting type heater from the outside of the extruder barrel in that the heating temperature can be easily controlled and uniform heating can be performed. This cast-type heater is preferably made of a material such as brass or cast iron from the viewpoint of adaptation to high temperatures.

An extruder (not shown) is provided in front of the first-stage pyrolysis reactor 1, and the raw material olefin polymer is heated and melted in advance by the extruder. The introduction into the vessel 1 is preferable because it can be applied to various raw material polymers having different physical properties and can be smoothly supplied to the pyrolysis apparatus. The heating temperature in this extruder is usually about 200 to 350 ° C.

Next, the reaction mixture obtained by the pyrolysis reaction in the screw type extruder 1b of the first stage pyrolysis reactor 1 is extruded from the reaction mixture outlet 6 of the screw type extruder 1b, and the flow path 7 Through the intermediate tank 8 and into the quantitative transfer means 2a of the second-stage pyrolysis reactor 2. At this time, the volatile component separated from the reaction mixture in the intermediate tank 8 is discharged from the volatile component outlet 9 provided in the intermediate tank 8 through the vent 4 of the screw type extruder 1b through the discharge path 5. You may make it merge with a volatile component and discharge it out of a system.

In the method of the present invention, if the discharge path 5 is set in a reduced pressure state, it is possible to promote the separation of volatile components containing a large amount of components which cause coloring of the pyrolysis wax from the reaction mixture, It is effective for obtaining a pyrolytic wax having excellent quality such as hue and odor.

Quantitative transfer means 2 of the second-stage pyrolysis reactor 2
a into the first-stage pyrolysis reactor 1
As in the above, the fixed amount transfer means 2a supplies the screw type extruder 2b at a predetermined flow rate. By precisely controlling the supply amount of the reaction mixture to the screw type extruder 2b by the quantitative transfer means 2a, the residence time of the reaction mixture in the screw type extruder 2b, that is, the thermal decomposition reaction time is accurately controlled. Can be.

The quantitative transfer means 2a and the screw type extruder 2b in the second stage pyrolysis reactor 2 are the same as the quantitative transfer means 1a and the screw type extruder 1b in the first stage pyrolysis reactor 1. It may be something.

The amount of the reaction mixture transferred to the screw-type extruder 2b by the quantitative transfer means 2a of the second-stage pyrolysis reactor 2, the heating temperature in the screw-type extruder 2b, the screw rotation speed, and the reaction mixture The extrusion amount and the like may be the same as those of the quantitative transfer means 1a and the screw type extruder 1b in the first-stage pyrolysis reactor 1, or may be different conditions.

Although the thermal decomposition reactor composed of the two-stage thermal decomposition reactor shown in FIG. 1 has been described above, the present invention is not limited to this two-stage thermal decomposition reactor, The number of stages can be appropriately selected so that a high degree of pyrolysis and high quality pyrolysis wax can be obtained.

Accordingly, the reaction mixture is discharged from the reaction mixture outlet 10 of the screw type extruder 2b of the second-stage pyrolysis reactor 2 and, if necessary, introduced into the intermediate tank 11 and further supplied to the subsequent-stage pyrolysis reactor. , And a thermal decomposition reaction is further performed.

In the method of the present invention, when an extruder is provided in the pyrolyzer and before the pyrolyzer, an inert atmosphere is also provided in the extruder to prevent the thermal degradation of the reaction mixture by oxygen. It is preferable because it is effective in suppressing it.

In the method of the present invention, as described above, the reaction mixture obtained by subjecting the olefin-based polymer to a thermal decomposition reaction by the thermal decomposition apparatus having a plurality of thermal decomposition reactors connected in series In this step, volatile components are further removed, and purification is performed by a treatment such as filtration. further,
By performing processes such as cooling, pulverization, and granulation, a solid pyrolytic wax can be produced.

By the way, when a thermal decomposition reaction accelerator such as a peroxide is not used, the degree of thermal decomposition achieved by using a single-stage extruder usually depends on the ratio of intrinsic viscosity [η] / [η] _O (Intrinsic viscosity of product after thermal decomposition / Intrinsic viscosity of raw material polymer before thermal decomposition) is about 0.85 to 1.0, and from the characteristics of the thermal decomposition reaction, the reaction mixture used for thermal decomposition [ [η] becomes smaller, the degree of thermal decomposition obtained becomes smaller even when the thermal decomposition reaction is carried out under the same conditions. Therefore, it is difficult to obtain a product having a high degree of decomposition by a usual method using a single-stage extruder. However, in the method of the present invention, the degree of thermal decomposition in a single-stage thermal decomposition reactor can be set to 0.5 to 0.75, and a plurality of thermal decomposition reactors are arranged to constitute a thermal decomposition apparatus. However, if pyrolysis is performed by this pyrolysis apparatus, a pyrolysis wax having a desired degree of decomposition can be efficiently produced. For example, according to the method of the present invention, it is possible to achieve a thermal decomposition degree of [η] / [η] _O of about 0.05 to 0.3, and the intrinsic viscosity of the product wax is 0.05 to 0.3.
About 0.4 can be obtained.

The pyrolysis wax obtained by the above method of the present invention can be obtained by appropriately selecting the number of stages of the pyrolysis reactor constituting the pyrolysis apparatus, the heating temperature in the pyrolysis reactor, the starting olefin polymer, and the like. You can get what you want. The resulting thermally decomposed wax has a very low content of thermally degraded products and is excellent in quality such as hue and molecular weight distribution. Therefore, the thermally decomposed wax obtained by the method of the present invention can be used as a pigment dispersant requiring sharpness of color (chromatic color) by utilizing these excellent qualities, and has a sharpness and releasability of an image. It is suitable for a wide range of uses, such as the required use for a copying machine toner or a resin modifier.

[0040]

According to the method of the present invention, the olefin polymer is thermally decomposed only by heating without using a thermal decomposition accelerator such as a peroxide by a simple apparatus and process. A pyrolysis wax having a degree of decomposition can be obtained.
In addition, the pyrolysis reaction can be performed continuously and stably for a long period of time without stopping operation and removing scale frequently, and high-quality product pyrolysis wax can be obtained with high efficiency and high yield. Obtainable.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an embodiment of a thermal decomposition apparatus used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First-stage pyrolysis reactor 1a Quantitative transfer means 1b Screw-type extruder 2 Second-stage pyrolysis reactor 2a Quantitative transfer means 2b Screw-type extruder 3 Raw material introduction path 4 Vent section of screw-type extruder 1b 5 Discharge path 6 Reaction mixture outlet of screw-type extruder 1b 7 Distribution path 8 Intermediate tank 9 Volatile component outlet 10 Reaction mixture outlet of screw-type extruder 2b 11 Intermediate tank

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-62804 (JP, A) JP-A-51-5274 (JP, A) JP-A-3-292305 (JP, A) JP-A-51-1982 135996 (JP, A) JP-B-48-1233 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 8/50

Claims (1)

(57) [Claims] 1. A method for producing a pyrolysis wax having a high degree of decomposition by supplying an olefin-based polymer to a pyrolysis apparatus and performing a pyrolysis reaction, wherein the pyrolysis apparatus quantitatively transfers a reaction mixture. A method for producing a thermally decomposed wax, comprising a plurality of pyrolysis reactors, each of which comprises a fixed-quantity transfer means and a screw-type extruder connected to the fixed-quantity transfer means.