JPH06100618A - Production of chlorinated polyolefin - Google Patents

Abstract

PURPOSE:To efficiently produce by the aqueous suspension method a chlorinated polyolefin having excellent solubility in organic solvents, e.g., toluene and xylene, and suitable for use in a coating composition or ink. CONSTITUTION:Chlorine is dissolved in an aqueous dispersion of polyolefin particles under such conditions that no free radical is generated. Thus, chlorine penetrates into the particles. The resulting particles are heated and/or irradiated with light to conduct chlorination. The two steps are repeated alternately to obtain a homogeneously and highly chlorinated, particulate polyolefin.

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 chlorinated polyolefin having excellent solubility in organic solvents.

[0002]

2. Description of the Prior Art Polyolefin powder is suspended in an aqueous medium and chlorine is introduced into it by heating it or irradiating it with light, and chlorine is continuously introduced for several hours. A technique for producing a modified polyolefin is widely known (see, for example, Japanese Patent Publication No. 36-4745 and Japanese Patent Publication No. 51-138791).

Such a chlorination method using an aqueous suspension method does not use a solvent, as compared with a chlorination method using a solution method, and thus does not require a complicated step of removing the solvent and has an adverse effect on the human body and the environment. It's a safe and economical way without.

However, the chlorinated polyolefin obtained by the aqueous suspension method described in the above reference has a
Toluene, which is not chlorinated sufficiently even inside the particles,
It does not dissolve in organic solvents such as xylene.

Therefore, although this kind of chlorinated polyolefin is suitable for applications such as molding resins, impact modifiers, flame retardants, etc., it can be used for coating materials using inexpensive general-purpose organic solvents such as toluene and xylene. It is not suitable for applications such as ink.

As a method for producing a chlorinated polyolefin completely soluble in an organic solvent such as toluene or xylene by an aqueous suspension method, Japanese Patent Laid-Open No. 3-199207 discloses a method.
Specific surface area obtained by pulverization is 300 to 20000 c
It has been proposed to chlorinate m ² / g polyolefin powder.

According to this technique, by increasing the surface area of the polyolefin powder, the chlorination reaction from the surface of the particles is promoted to increase the degree of chlorination, thereby improving the solubility in an organic solvent.

[0008]

However, polyolefins are not easily pulverized into fine particles, and in order to finely pulverize them, a fine pulverizer having a special mechanism or a dissolution precipitation method using a special solvent is generally adopted. However, such a method has the disadvantages that the cost of micronization is extremely high and the production cost of chlorinated polyolefin is high.

Further, simply, the specific surface area is 300 to 2 on average.
If only 0000 cm ² / g of polyolefin powder is used, coarse particles are also mixed, and although the degree of chlorination can be increased to some extent, the particles may aggregate during the chlorination reaction. It is not possible to uniformly chlorinate inside. Therefore, the solubility in the organic solvent is insufficient.

Therefore, in practice, the particles must be disaggregated from the agglomerates during the chlorination reaction by ball milling the particles or by forced circulation with a vortex pump.

However, in such a method, it is difficult to say that it is an efficient manufacturing method because a particle processing facility must be newly added, and this processing is troublesome.

The present invention solves the above problems.
An object of the present invention is to provide a method for efficiently producing a chlorinated polyolefin excellent in solubility in an organic solvent at low cost by an aqueous suspension method.

[0013]

The polyolefin used in the present invention is a homopolymer of ethylene or α-olefin,
It is a copolymer of ethylene and α-olefin, and a copolymer of ethylene and other monomer.

Examples of homopolymers of ethylene and α-olefins include polyethylene, polypropylene, polybutene, polyhexene, poly-4-methylpentene and the like.

As the copolymer of ethylene and α-olefin, for example, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer,
Examples thereof include an ethylene-octene copolymer, an ethylene-4-methylpentene copolymer, an ethylene-propylene-butene copolymer and a propylene-butene copolymer.

Examples of copolymers of ethylene and other monomers include ethylene-acrylic acid copolymers, ethylene-butadiene copolymers, ethylene-vinyl chloride copolymers and ethylene-vinyl acetate copolymers. .

Oxidation treatment of these polyolefins
It does not matter even if chemical modification such as maleic anhydride treatment is performed.

The molecular weight of the polyolefin is not specified, but in order to use the chlorinated polyolefin obtained by dissolving it in an organic solvent, a low molecular weight is preferable, and a weight average molecular weight of 1,000 to 50,000 is preferable. Further, structurally, it may be any of isotactic, syndiotactic and atactic.

The particle size of the polyolefin powder is generally the same as the particle size of the powder used in the conventional aqueous suspension method. As the particle size increases, it takes time for chlorine to penetrate into the powder and granules. Therefore, a powder and granule with a maximum particle size of 1 mm or less is preferable, and more preferably a powder and granule with a maximum particle size of 500 μm or less. Is.

Such a powder or granule can be prepared by subjecting a polyolefin polymer obtained by a known method to a suitable sieve. Alternatively, the polyolefin polymer can be prepared by once pulverizing it with a known general-purpose pulverizer and then sieving it. In this case, since the particle size is relatively coarse, the crushing cost does not increase significantly.

In the present invention, first, (1) chlorine is dissolved in an aqueous suspension of a polyolefin powder or granular material under the condition that radicals are not generated. In order to uniformly chlorinate the polyolefin, it is preferable that the chlorine penetrates into the powder and is saturated and then the chlorination reaction is performed. Therefore, it is preferable to supply chlorine to the suspension so that the chlorine is saturated in the suspension and hold it for a certain period of time. By doing so, chlorine spontaneously diffuses into the interior of the polyolefin powder and granules. Is saturated.

It is preferable that the pressure of chlorine at the time of dissolving chlorine in the aqueous suspension is higher because the saturated concentration of chlorine in the aqueous medium and the granular material is also higher, but the pressure resistance of the reaction vessel is limited. Therefore, in general, it is preferable to set 1 to 5 kg / cm ² .

The chlorine may be in the form of gas or liquid, and may be supplied in suspension or in the gas phase.

The fact that chlorine is substantially saturated in the granular material means that chlorine is introduced into the aqueous medium and dissolved in the aqueous medium in a state where the polyolefin granular material is suspended in the aqueous medium. That the chlorine dissolved in the medium has reached saturation,
It can be indirectly (substantially) confirmed based on the measurement by a known chlorine concentration measuring method.

As the chlorine concentration measuring method, for example, a method is used in which a fixed amount of an aqueous medium in which chlorine is dissolved is sampled, potassium iodide is added thereto to release iodine, and the iodine is titrated with sodium thiosulfate. It

If the above holding time is too short, chlorine will not reach saturation, and the chlorine concentration inside the powder or granular material will decrease, and conversely it will be meaningless to hold for a long time after reaching saturation. Retention time, the particle size of the polyolefin powder, the temperature of the aqueous medium,
Depending on the chlorine pressure introduced, etc., when using a polyolefin powder with a maximum particle size of 1 mm or less, it is generally 5
~ 30 minutes is suitable.

Water is preferably used as the aqueous medium of the aqueous suspension, but a dispersant may be added to water in order to prevent aggregation of the polyolefin during the reaction. Alternatively, a hydrochloric acid aqueous solution may be used.

As the dispersant, for example, acrylic acid copolymer derivatives such as ammonium salt of methacrylic acid methyl ester-acrylic acid copolymer, alkylene oxides such as ethylene oxide-propylene oxide copolymer, Examples thereof include phosphoric acid esters and sulfonic acid compounds. The amount of the dispersant added is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polyolefin powder and granules.

The conditions under which radicals are not generated are light, heat,
Alternatively, it means a condition that the chlorination reaction is not started by the radical generator. That is, in the above step (1), the light source for starting the reaction and the radical generator are not used. Further, in the case of a heat source, sufficient radicals are generated at 90 ° C. or higher for the progress of the reaction.
It is carried out at temperatures below 0 ° C.

Next, (2) under the condition that radicals are generated,
Chlorine a polyolefin. The conditions under which radicals are generated mean the conditions under which the chlorination reaction is initiated by light, heat, or a radical generator.

In the present invention, the step (1) of dissolving chlorine and the step (2) of chlorination are alternately repeated until a predetermined degree of chlorination is reached.

In the second to fourth aspects of the present invention, the dissolving step (1)
Is carried out by dissolving chlorine in the aqueous suspension at a temperature below 90 ° C. for 5 to 30 minutes.

In 2 of the present invention, the chlorination step (2) is 90
It is carried out by irradiating with light at a temperature below 0 ° C for 1 to 10 minutes. The wavelength of light is preferably 200 to 600 nm.

In 3 of the present invention, the chlorination step (2) is 90
It is carried out by heating in the range of ° C to the softening temperature of the polyolefin for 1 to 10 minutes. If the reaction temperature exceeds the softening temperature of the polyolefin, the powdery particles will coalesce with each other. Therefore, the reaction temperature is lower than the softening temperature of the polyolefin used. The softening temperature mentioned here is a differential scanning calorimeter (DS).
It indicates the endothermic start temperature in C).

In 4 of the present invention, the chlorination step (2) is 90
The heating is performed for 0.5 to 5 minutes in the range of ℃ to the softening temperature of the polyolefin and irradiation with light.

Radical generators such as organic peroxides and azo compounds have a long half-life and it is difficult to control the radical generation period, so it is preferable not to use them.

The reaction temperature may be set to a constant temperature in one step, and is set to two or more different temperatures in order to prevent agglomeration of the polyolefin powder particles during the reaction or to increase the reactivity. Then, the chlorination reaction may be carried out.

In this way, the chlorination reaction proceeds, and chlorine which is substantially saturated in the powder and granules is consumed, but chlorine is continuously supplied from the suspension. Therefore, during the chlorination step, the chlorine supplied is chlorinated into a polyolefin near the surface layer of the powder or granular material before reaching the inside of the powder or granular material.

Therefore, if the time of the chlorination step (2) is too long, the degree of chlorination near the surface layer of the powder and granules becomes high, and the chlorination becomes uneven. Therefore, the chlorination time is 1 when the heat source or the light source is used alone.
Limited to 10 minutes. When using a heat source and a light source together, it is limited to 0.5 to 5 minutes.

Generally, the solubility of chlorinated polyolefins in organic solvents decreases as the chlorine content decreases. On the contrary, in order to obtain a high chlorine content, a long-time chlorination reaction is required, which is not economical.

Therefore, the degree of chlorination of the finally obtained chlorinated polyolefin is generally 2 in terms of chlorine content.
The content is 5 to 70% by weight, preferably 60 to 70% by weight. In order to obtain such a degree of chlorination, the steps (1) and (2) described above are different depending on the conditions, but normally 1
It is repeated zero or more times.

[0042]

[Function] When a polyolefin powder or granular material is suspended in an aqueous medium and chlorine is introduced into the suspension for chlorination, when chlorine is introduced while introducing chlorine as in the prior art, chlorine is the center of the particles. Difficult to penetrate to the part. Further, the particles become larger as they are chlorinated, and it becomes more difficult for chlorine to penetrate to the center of the particles.

Moreover, since the chlorination reaction rate is much faster than the diffusion and permeation rate of chlorine, the vicinity of the surface of the particle is preferentially chlorinated, and finally the chlorination degree at the center of the particle is extremely low. It becomes difficult for the low chlorinated portion in the central portion to dissolve in an organic solvent such as toluene or xylene.

Therefore, when chlorine is dissolved in an aqueous suspension of polyolefin powder and granules under the condition that radicals are not generated, and then the polyolefin is chlorinated under the condition that radicals are generated, chlorine is internally contained in the powder and granules. Permeate, and the granular material is chlorinated almost uniformly from near the surface to the central portion.

In this way, the process of diffusion and permeation of chlorine into the polyolefin powder and the process of chlorination are separated, and the steps (1) and (2) are alternately performed until the desired degree of chlorination is reached. Repeatedly, the powder is always chlorinated in the state where chlorine is diffused and saturated to the inside of the powder, which makes it less likely that the degree of chlorination will be uneven inside and outside the powder. Chlorinated.

EXAMPLES Examples and comparative examples of the present invention will be shown below.
In the following, "parts" means "parts by weight". Example 1 Weight average molecular weight 15,000, density 0.89 g / cm ² , softening temperature (by DSC) 105 ° C., maximum particle size 500 μ
100 parts of polypropylene powder or granules of m were charged into a pressure reactor equipped with a stirrer, the inner surface of which was lined with glass, and 10000 parts of ion-exchanged water was added to the reactor, and as a dispersant, an ethylene oxide-propylene oxide copolymer (average) was added. 0.2 parts with a molecular weight of 4000 and a composition molar ratio of 1: 1) were added.

First, (1) heating the pressure reactor to 85 ° C.
The pressure of chlorine in the reactor is 4.5 k
Liquefied chlorine was introduced into the suspension so as to be g / cm ² , and the liquefied chlorine was introduced and held for 10 minutes, after which the introduction of liquefied chlorine was stopped.

Next, (2) the high pressure mercury lamp (wavelength 25
The chlorination reaction by light was performed while irradiating (4 to 560 nm) for 2 minutes. Further, the operation (1) and the operation (2) were alternately repeated 20 times.

The chlorine content of the chlorinated polypropylene powder thus produced was measured by the oxygen flask combustion method.
The average chlorine content was 60.1% by weight.

2 parts of the obtained chlorinated polypropylene powder granules
When 20% by weight of toluene was added to 5 ° C. and the mixture was stirred for 1 hour to dissolve it, a solubility test was conducted.
All were completely transparent and had no insoluble portion.

Example 2 In Example 1, after the introduction of liquefied chlorine was stopped, instead of the chlorination reaction by light, this was heated to 100 ° C. and heated to chlorination by heat for 5 minutes. After that, the temperature is lowered to 85 ° C. Other than that was performed like Example 1.

The average chlorine content of the produced chlorinated polypropylene powder was 60.1% by weight. As for the solubility in toluene, the whole was completely transparent and had no insoluble portion.

Example 3 In Example 1, instead of the polypropylene powder, a polyethylene powder having a weight average molecular weight of 4000, a density of 0.93 g / cm ² , a softening temperature (by DSC) of 90 ° C., and a maximum particle size of 500 μm was used. I used my body.

The operation (1) and the operation (2) were alternately repeated 30 times. Other than that was performed like Example 1.

The average chlorine content of the produced chlorinated polyethylene powder was 59.3% by weight. As for the solubility in toluene, the whole was completely transparent and had no insoluble portion.

Example 4 In Example 1, the holding time from the introduction of liquefied chlorine was set to 2
The irradiation time of the high-pressure mercury lamp was changed to 5 minutes.

The operation (1) and the operation (2) were alternately repeated 15 times. Other than that was performed like Example 1.

The average chlorine content of the produced chlorinated polyethylene powder was 62.5% by weight. As for the solubility in toluene, the whole was completely transparent and had no insoluble portion.

Comparative Example 1 Weight average molecular weight 15,000, density 0.89 g / cm ² , softening temperature (by DSC) 105 ° C., maximum particle size 500 μ
100 parts of polypropylene powder or granules of m were charged into a pressure reactor equipped with a stirrer, the inner surface of which was lined with glass, and 10000 parts of ion-exchanged water was added to the reactor, and as a dispersant, an ethylene oxide-propylene oxide copolymer (average) was added. 0.2 parts with a molecular weight of 4000 and a composition molar ratio of 1: 1) were added.

Then, the pressure reactor was heated and kept at 85 ° C. under stirring to obtain a high pressure mercury lamp (wavelength 254 to 560 nm).
The chlorine pressure inside the reactor was 4
Liquefied chlorine is continuously introduced so that the concentration becomes kg / cm ² ,
The chlorination reaction by light was carried out for 1 hour.

The average chlorine content of the produced chlorinated polypropylene powder was 62.4% by weight. Moreover, in the solubility test with respect to toluene, an insoluble portion remained. The insoluble portion was filtered, vacuum dried, and the weight thereof was measured. As a result, the insoluble portion was 8.5% by weight.

Comparative Example 2 A polyethylene powder having a weight average molecular weight of 4000, a density of 0.93 g / cm ² , a softening temperature (by DSC) of 90 ° C. and a maximum particle size of 500 μm was used. Also, the heating temperature is 100
C. and the chlorination reaction time was changed to 2 hours. Other than that was performed like Comparative Example 1.

The average chlorine content of the produced chlorinated polyethylene powder was 60.1% by weight. Moreover, in the solubility test with respect to toluene, an insoluble portion remained. This insoluble portion was filtered, dried in vacuum, and its weight was measured.

[0063]

The method for producing a chlorinated polyolefin of the present invention is as described above. Chlorine is rapidly permeated and diffused into the inside of the granular material, and is chlorinated in that state. It is chlorinated uniformly up to the center and highly chlorinated.

Therefore, by pulverizing the polyolefin,
There is an advantage that the manufacturing cost can be remarkably reduced because it is not necessary to use the polyolefin powder particles having a specific surface area.

In addition, it is possible to completely use inexpensive organic solvents such as toluene and xylene without adding a troublesome operation such as crushing the particles with a ball mill in the course of the chlorination reaction or forcedly circulating with a spiral pump. There is an advantage that a soluble chlorinated polyolefin can be efficiently produced.

Therefore, the chlorinated polyolefin obtained by the production method of the present invention is suitable for use in paints and inks. In addition, this chlorinated polyolefin,
It can also be used in applications such as molding resins, impact modifiers and flame retardants.

Claims (4)

[Claims] 1. A process of (1) dissolving chlorine in an aqueous suspension of a polyolefin powder or granular material under conditions where radicals are not generated, and (2) a process of chlorinating polyolefin under conditions where radicals are generated are alternated. A method for producing a chlorinated polyolefin characterized by repeating the above. 2. A step of (1) dissolving chlorine in an aqueous suspension of polyolefin powder and granules at a temperature of less than 90 ° C. for 5 to 30 minutes, and (2) exposing at a temperature of less than 90 ° C. for 1 to 10 minutes. A method for producing a chlorinated polyolefin, characterized in that the step of irradiating with chlorine to chlorinate the polyolefin is alternately repeated. 3. A step of (1) dissolving chlorine in an aqueous suspension of a polyolefin powder or granular material at a temperature of less than 90 ° C. for 5 to 30 minutes, and (2) a temperature range of 90 ° C. to a softening temperature of the polyolefin. A method for producing a chlorinated polyolefin, characterized in that the step of chlorinating the polyolefin by heating for 1 to 10 minutes is alternately repeated. 4. A step of: (1) dissolving chlorine in an aqueous suspension of polyolefin powder and granules at a temperature of less than 90 ° C. for 5 to 30 minutes; and (2) at a temperature range of 90 ° C. to the softening temperature of the polyolefin. A method for producing a chlorinated polyolefin, characterized in that the step of chlorinating the polyolefin by heating it for 0.5 to 5 minutes is alternately repeated.