JPH0457808A - Production of thermal decomposition wax - Google Patents

Abstract

PURPOSE:To obtain a thermal decomposition wax high in quality such as hue, odor, flash point and molecular weight distribution by thermally decomposing an olefin polymer and devolatilizing the reaction mixture rapidly at high efficiency. CONSTITUTION:An olefin polymer (e.g. polyethylene) is thermally decomposed in a thermal decomposition reactor. The obtained reaction mixture is fed at high temperature to an evaporator connected to the thermal decomposition reactor, and the reaction mixture is evaporated while an inert gas is blown into the evaporator to devolatilize the product. The reaction mixture is withdrawn from the evaporator to obtain a thermal decomposition wax. The obtained wax can be desirably used as a pigment dispersant requiring clearness of color, a copier toner requiring clearness of image and mold release, a modifier for food resin requiring odorlessness or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing pyrolytic wax, and in particular to a method for efficiently removing volatile components produced by a pyrolysis reaction of an olefinic polymer from a reaction mixture using a simple device. It relates to a method that can be used to remove

<Prior art> Low molecular weight polyolefins such as polyethylene and polypropylene are used as waxes as pigment dispersants, rubber processing aids,
It is used in a wide range of applications such as resin processing aids, additives for inks or paints, fiber treatment agents, and toners for electrostatic copying.
In recent years, the demand for waxes for these uses has been increasing, and demands for higher quality waxes have become increasingly strict.

By the way, there are methods for obtaining this low molecular weight polyolefin, such as a method by telomerization of olefin, a method of thermally decomposing high molecular weight polyolefin, and a method of separating and purifying low molecular weight polyolefin which is a by-product in the production of high molecular weight polyolefin. .

<Problems to be Solved by the Invention> In the method using thermal decomposition, volatile components consisting of low molecular weight hydrocarbons etc. are generated by thermal decomposition of polyolefins, and these are contained in the final product of thermal decomposition wax. If even a small amount remains, the quality of the pyrolytic wax, such as the amount of residual volatile matter, odor, flash point, and molecular weight distribution, will deteriorate. In addition, oxygenated hydrocarbons produced by the oxidation of low molecular weight hydrocarbons by air accompanying the raw material polyolefin or air leaking during the process deteriorate the hue of the pyrolyzed wax product, and depending on the separation method, Since the separation effects differ, it is necessary to efficiently remove these volatile components during the manufacturing process.

Therefore, the object of the present invention is to provide a method that can quickly and efficiently remove volatile components generated by thermally decomposing an olefinic polymer from a reaction mixture, thereby producing a high-quality pyrolyzed wax. Our goal is to provide the following.

Means for Solving the Problems> In order to solve the above problems, the present invention provides a method in which a reaction mixture obtained by subjecting an olefin polymer to a thermal decomposition reaction in a thermal decomposition reactor is connected to the thermal decomposition reactor. The reaction mixture is evaporated while blowing an inert gas into the evaporator, the volatile components separated from the reaction mixture are extracted from the evaporator, and the reaction mixture is extracted from the evaporator. The present invention provides a method for producing a pyrolytic wax containing a pyrolytic wax.

It is also preferable to arrange an insert inside the evaporator to facilitate separation of volatile components from the reaction mixture inside the evaporator.

Hereinafter, the method for producing pyrolytic wax of the present invention (hereinafter simply referred to as "method") will be described in detail.

The olefinic polymer that is the starting material for the method of the present invention is
α-olefin homopolymer, at least two types of α-olefins
Examples include copolymers consisting of -olefins, and copolymers consisting of α-olefins and other monomers copolymerizable with the α-olefins.

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

Other monomers that can be copolymerized with α-olefins include polybasic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, acrylic esters, methacrylic esters, vinyl acetate, and maleic acid; Examples include anhydrides and esterified products thereof. These are 1
A single species or two or more species may be contained in the olefin polymer.

In the method of the present invention, these olefin polymers are thermally decomposed at a temperature of usually about 350 to 450°C, and volatile components produced by the thermal decomposition reaction are removed from the reaction mixture.

Thermal decomposition of the olefin polymer may be carried out using any reactor such as a tank reactor or a tubular reactor. When thermal decomposition is carried out using a tubular reactor, an extruder is connected to the front stage of the tubular reactor, and the raw material olefin polymer is first supplied to this extruder and melted, and then the molten olefin polymer is By supplying the polymer to a tubular reactor, it is possible to smoothly supply a wide variety of raw materials with different physical properties, and the thermal decomposition reaction can be carried out efficiently. ,preferable.

In the method of the present invention, volatile components generated by the thermal decomposition reaction in the thermal decomposition reactor are removed. The volatile components produced by this thermal decomposition reaction usually consist of hydrogen and hydrocarbons having about 1 to 35 carbon atoms, but they vary depending on the type of olefin polymer that is the starting material. , when the starting material is polyethylene, a hydrocarbon having about 25 to 30 carbon atoms; when the starting material is polypropylene,
The main component is a hydrocarbon having about 8 to 13 carbon atoms. In addition to these hydrocarbons, trace amounts of oxygenated hydrocarbons may be present in the starting materials or due to air leaking during the manufacturing process. This causes the hue of the wax to deteriorate.

Regarding this oxygen-containing hydrocarbon, the presence of hydroxyl groups, carbonyl groups, and carboxyl groups has been confirmed by subjecting the entire volatile component to infrared absorption analysis after silica gel fractionation treatment and thin layer chromatography treatment.

The present invention will be explained below based on the embodiment of the present invention shown in FIG.

In Figure 1, 1 is the evaporator, 2 is the reaction mixture population, and 3 is the evaporator.
4 indicates an inert gas inlet, 4 indicates a volatile component outlet, 5 indicates a reaction mixture outlet, and 6 indicates an insert arranged in the evaporator.

A reaction mixture produced by a thermal decomposition reaction of an olefinic polymer in a thermal decomposition reactor (not shown) is introduced into the evaporator 1 from a reaction mixture population 2 of the evaporator 1 .

The evaporator 1 may be of any type, such as a tower, a tube, or a tower, and is particularly effective in providing good contact between the reaction mixture and the inert gas, stabilizing the degree of decomposition of the raw material olefin polymer, and A column-shaped one is preferable because it is easy to operate stably.

The temperature of the evaporator is such that volatile components do not condense and do not dissolve in the wax, especially oxygenated hydrocarbons, which cause coloration of the product pyrolysis wax and are difficult to separate in subsequent processes, dissolve in the wax. The temperature is adjusted to a high temperature of about 250 to 430°C, preferably about 300 to 400°C, in order to save energy because the reaction mixture can be treated at a high temperature in the pyrolysis reactor.
Further, the pressure of the evaporator is, for example, 500 Torr to
i, about 8kg/cm2G, preferably 750~
It is adjusted to about 0.5kg/cm2G. This condition has the advantage that special equipment such as a vacuum pump and a pressure control system is not required, and stable operation is easy with a simple process.

The volatile components separated from the reaction mixture are transferred to the volatile component outlet 4.
The condensed liquid is extracted from the water and subjected to condensation treatment in a condenser (not shown), and the resulting condensate is discharged as waste oil, and the remaining non-condensable gas is incinerated to prevent the generation of odors. It may be subjected to treatment.

In the method of the invention, the inert gas population 3 of the evaporator 1
An inert gas is blown into the reaction mixture in countercurrent contact to facilitate the discharge of the volatile components from the volatile component outlet 4.

Examples of the inert gas used include nitrogen gas, carbon dioxide gas, water vapor, and the like, with nitrogen gas being preferred. In addition, the amount of inert gas blown is adjusted appropriately depending on the amount of reaction mixture flowing in from the pyrolyzer, that is, the amount to be treated, the type of olefin polymer used, the degree of pyrolysis, etc., but usually , 0.1 to 20 mol, preferably about 1.-5 mol, per 1 kg of the reaction mixture.

Inside the evaporator, if the evaporator is column-shaped or tubular,
The provision of trays, static mixers, packing, or the use of wetted walls improves the contact between the reaction mixture and the inert gas and facilitates the separation of volatile components from the reaction mixture. can be done more efficiently,
preferable.

The shelves used are not particularly limited, but include, for example, bubble bell trays, Uniflux trays, perforated plate trays, valve-type trays (flexi trays, Natsuta float valve trays, ballast trays, etc.), cascade trays, venturi trays, Kirachil trays, recycling trays, jet trays, Examples include turbo grid trays, ripple trays, dual flow trays, baffle trays, ring ant donut trays, etc.

The static mixer is not particularly limited, but for example,
Kenix type, Sulzer type, Sugaya mixer T,
-RO3S LPD mixer and the like.

In addition, the filling may be made of porcelain or metal as a material that can withstand the high temperature inside the evaporator, and its format is not particularly limited, such as spherical packing, ring-shaped packing (Raschig ring, Lessing ring, Spiral ring, Cross partition ring, Ball ring), Saddle type filling (Berl saddle, Interlocks saddle), Spray pack, Banaback, Gutsudroy backing, Stedman backing, Dixon ring, McMahon backing, Canon Protroputs Examples include metal backing, helix, terraret, vertical plate filling, and the like.

The wetted wall can be constructed by using the inner wall of the tower body or by forming a multi-tube structure. When using the column body, there is no insert inside the evaporator, resulting in the simplest tubular structure.

Among the above various interpolations, in the method of the present invention,
Suitable for reaction mixtures that have high viscosity and may contain foreign substances, and have a simple structure, trays are suitable for perforated trays, jet trays, ripple trays, dual flow trays, baffle trays, and ring ant trays. - In the case of a static mixer, the nut tray has all of the above-mentioned examples, and in terms of the packing, it has a spherical packing, a ring-shaped packing, and a saddle-shaped packing, and the wetted wall has the two types of structures shown in the above-mentioned examples. From the viewpoint of the scale of the evaporator to be installed and the separation performance, the number of these inserts to be installed is preferably about 2 to 3 theoretical stages.

In the evaporator the volatile components are separated and the reaction mixture exits 5
In the subsequent step, the reaction mixture taken out from
After the decomposition reaction is stopped by cooling, foreign substances are separated by filtration, and solidified by cooling to obtain a solid pyrolytic wax.

The desired pyrolytic wax obtained by the above method can be obtained depending on the heating temperature in the tubular pyrolyzer, the olefin polymer used, etc., and is homogeneous with a narrow molecular weight distribution. , hue, heat resistance,
In terms of flash point, odor, thermal stability, etc., it is of high quality, especially with a low content of volatile components.

Therefore, the pyrolytic wax obtained by the method of the present invention takes advantage of these excellent qualities to produce a variety of colors (chromatic colors).
Applications for pigment dispersants that require sharpness of images, applications for toners for copying machines that require sharpness of images and releasability, and
Suitable for a wide range of applications, including food products where odorlessness and hygiene are important, resin modifiers for pharmaceuticals, hot melt applications where heat resistance and stability are required, and heat-resistant ink applications. .

<Example> Hereinafter, the present invention will be specifically explained with reference to Examples of the present invention.

(Example 1) Using a tubular pyrolyzer connected to an extruder, polypropylene with an intrinsic viscosity [η]=1.6 was pyrolyzed under the following conditions.

Extruder screw diameter: 39.85m Field cylinder diameter: 40. Omm Extruder temperature (temperature at extruder outlet) 300 ℃ Extrusion speed: 10, 5 kg/hr Tubular pyrolysis reactor diameter: 50 mm Heating temperature = 402 ℃ Internal pressure normal pressure residence time + 33 m1n (raw material supply amount basis) The obtained reaction mixture (pyrolyzer outlet temperature 400°C) was
Evaporator, schematically shown in Figure 1, connected to a pyrolyzer: Dimensions: 2 inch internal diameter, 1 m length tubular insert: Kenix-type static mixer Temperature: 380°C; Introduce nitrogen gas from inlet 2 and inert gas at 35ONjl! /
It was blown in at a flow rate of hr to evaporate. The volatile components separated from the reaction mixture were continuously extracted from the volatile component outlet 4, cooled and processed in a subsequent step (not shown).
On the other hand, the reaction mixture from which volatile components have been separated is taken out from the reaction mixture outlet 5, rapidly cooled to 200°C to completely stop the thermal decomposition reaction, and then filtered, cooled and solidified to obtain a thermally decomposed wax. Ta.

The melt viscosity, volatile content, flash point, powder hue, melt color, and weight average molecular weight (Mw
) and number average molecular weight (Mn) (Mw/Mn) and odor were evaluated or measured according to the following methods.
The results are shown in Table 1.

a. Melt viscosity A pyrolyzed wax sample was heated to 180° C. to melt it and measured using a Brookfield viscometer.

b. Place about 2 g of volatile pyrolyzed wax sample into a constant temperature hot air dryer,
It was held at 150° C. for 2 hours, and the weight loss was taken as volatile matter.

C9 flash point Measured using a TAG sealed flash point measuring device.

d. Powder Hue The sample was ground into a powder with an average particle size of about 300) m, and the hue of this powder was measured using a Hunter Lab color difference meter.

e. Melting color The sample was melted at 180°C, and the color of the melted sample was compared with a Hazen standard colorimetric solution using a colorimetric tube.

f2 Weight average molecular weight (Mw) and number average molecular weight (Mn
) Upper body (M stomach/Mn) was measured by GPC method.

g A sensory test was conducted using subjects with normal odor sense.

(Comparative Example 1) A pyrolyzed wax was obtained in the same manner as in Example 1, except that the reaction mixture discharged from the tubular pyrolyzer was not introduced into the evaporator and was cooled to 200°C to separate volatile components. .

Melt viscosity, volatile content, flash point of the obtained pyrolytic wax,
Powder hue, melt color, weight average molecular weight (which represents molecular weight distribution)
Ratio of Mw ) and number average molecular weight (Mn ) (Mw/Mn)
and odor were evaluated or measured in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2) A pyrolyzed wax was obtained in the same manner as in Example 1 except that nitrogen gas was not blown into the evaporator.

Melt viscosity, volatile content, flash point of the obtained pyrolytic wax,
Powder hue, melt color, weight average molecular weight (which represents molecular weight distribution)
The ratio of Mw) to number average molecular weight (Mn) (Mw/Mn) and odor were evaluated or measured in the same manner as in Example 1. The results are shown in Table 1.

Pyrolytic wax was obtained in the same manner as in 1.

Melt viscosity, volatile content, flash point of the obtained pyrolytic wax,
Powder hue, melt color, weight average molecular weight (which represents molecular weight distribution)
The ratio of Mw) to number average molecular weight (Mn) (Mw/Mn) and odor were evaluated or measured in the same manner as in Example 1. The results are shown in Table 1.

<Effects of the Invention> According to the method of the present invention, volatile components can be removed quickly and with high efficiency from the reaction mixture obtained by thermally decomposing an olefin polymer, so that the content of volatile components can be reduced. It is possible to obtain a pyrolytic wax of high quality in terms of hue, odor, flash point, molecular weight distribution, etc. of the powder and melt. Also, among volatile components, it suppresses the mixing of oxygenated hydrocarbons, which are the main cause of deteriorating the color of the product, with the product pyrolysis wax, and prevents the oxygenated hydrocarbons from dissolving into the pyrolysis wax. Therefore, it is possible to obtain a pyrolyzed wax having a low content of oxygenated hydrocarbons and a good hue. Furthermore, the method of the present invention can produce high-quality pyrolytic wax with high efficiency using a simple device, and has high industrial practical value.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating one embodiment of the method of the present invention. Explanation of symbols 1... Evaporator, 2...reaction mixture inlet; 3...Inert gas population, 4... Volatile component outlet, 5... reaction mixture outlet, 6...Interpolation FI G, 1

Claims (1)

[Claims] A reaction mixture obtained by subjecting an olefin polymer to a pyrolysis reaction in a pyrolysis reactor is introduced at high temperature into an evaporator connected to the pyrolysis reactor, and the reaction mixture is heated while blowing an inert gas into the evaporator. A method for producing a pyrolytic wax comprising the steps of: evaporating a reaction mixture; extracting a volatile component separated from a reaction mixture from an evaporator; and extracting a reaction mixture from an evaporator.