JP2725483B2 - Production method of chlorinated polyolefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a solvent-soluble chlorinated polyolefin by chlorinating a low-molecular-weight polyolefin.

[0002]

2. Description of the Related Art At present, chlorinated polyolefins are generally produced industrially by chlorination in a solvent and chlorination in an aqueous suspension. In the chlorination method in a solvent, chlorination is performed in an inert chlorine-based solvent such as carbon tetrachloride, so that a relatively uniform chlorination reaction is performed.However, in order to dissolve and react the polyolefin, a high molecular weight polyolefin is used as a raw material. Then, the reaction system becomes highly viscous, and the polyolefin concentration and the molecular weight are restricted. This method is often practiced for the production of solvent-soluble, relatively low molecular weight chlorinated polyolefins for use in paints, adhesives, inks and the like. However, a method that does not use a halogen-containing solvent such as carbon tetrachloride is required from the viewpoint of environmental problems.

On the other hand, in chlorination in aqueous suspension, if the chlorination reaction is carried out at a temperature near or above the melting point of the polyolefin, coagulation or agglomeration occurs during the chlorination and uniform chlorination cannot be performed. The following chlorination methods have been used. Therefore, the raw material polyolefin used in the aqueous suspension method is suitably of a relatively large molecular weight, for example, tens of thousands or more, and the obtained chlorinated polyolefin has been commercialized mainly for polymer blends and molding materials.

A molecular weight of 10,000 which is usually called wax
Since the following polyolefins have a low softening point and a low melting point, if they are chlorinated in an aqueous suspension, flocculation and agglomeration extremely easily occur. Therefore, the aqueous suspension method is not used. However, when chlorination is intentionally performed, it is generally performed at a temperature lower than the melting point. As a result, the chlorination must be carried out at a low reaction temperature, and the reaction becomes extremely slow. In order to increase the reaction rate, methods such as irradiation with ultraviolet rays or addition of a radical generator are known, but there is a disadvantage that the reaction requires a long time.
In the chlorination of polyolefin by the aqueous suspension method, since the polyolefin is dispersed in water in the form of powder and is chlorinated, the surface of the polyolefin particles is more easily chlorinated from the central portion, so that an uneven chlorinated product is produced. Or polyolefin crystals are apt to remain. Thus, chlorinating a low-molecular-weight polyolefin under aqueous suspension to produce a solvent-soluble chlorinated polyolefin further affects the productivity because the reaction temperature is low and the chlorination rate does not increase. Since the chlorinated polyolefin is liable to become a non-uniform chlorinated product, there is a disadvantage that an insoluble material is easily generated in an organic solvent.

[0005]

In view of the above, the present inventors have made intensive studies to obtain a method for producing a solvent-soluble chlorinated polyolefin without using a halogen-containing solvent. As a result, they have found that the above object can be achieved by chlorinating a low-molecular-weight polyolefin in a molten suspension in water under specific conditions, and completed the present invention.

[0006]

According to the present invention, a polyolefin having a number average molecular weight of 800 to 12000 and a melt viscosity at 170 ° C. of 4,000 centipoise or less is converted to water 10
1 to 20 parts by weight per 0 parts by weight of the polyolefin
Down the a method of producing solvent-soluble chlorinated polyolefin, wherein the chlorinating in the molten suspension at high temperatures 5 ° C. or higher than the aqueous medium NakaToru point.

The present inventors have conducted detailed studies focusing on the fact that low-molecular-weight polyolefins easily melt at temperatures higher than their melting points and have low melt viscosities. It has been found that it can easily become a molten suspension in water. In this case, the molten suspension state refers to a state in which the liquid polyolefin melted in water is dispersed. Chlorinated polyolefins in the molten suspension, the conventional polyolefin in the aqueous suspension process and chlorine of the reaction a solid - of the different molten liquid material was dissolved chlorine reaction in medium - dissolved chlorine in the medium Since the reaction is a reaction, the degree of freedom of the polyolefin is very good, and the droplet particles are small and the surface area is large, so that a uniform chlorination reaction occurs and a homogeneous chlorinated polyethylene can be obtained.

[0008] The polyolefin used in the present invention is a homopolymer or a copolymer of polyolefin in the form of powder, pellets or coarse particles, for example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, propylene-propylene. Polymers having a crystal structure such as butene copolymer, ethylene-acrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-butadiene copolymer, ethylene-maleic acid copolymer or partially oxidized polyethylene Alternatively, it refers to an amorphous polymer having a number average molecular weight of 800 to 12,000 and a melt viscosity at 170 ° C. of 4,000 centipoise or less.

[0009] Molecular weight 12,000 or more, melt viscosity 4000
Polyolefins having a cP (170 ° C.) or higher have a too high viscosity even when melted, so that it is difficult to form a molten suspension in water. In addition, the chlorinated product undergoes a large increase in melt viscosity during chlorination, resulting in aggregation and agglomeration. Not suitable because it is easy. Further, polyolefins having a molecular weight of less than 800 are not preferable because, for example, when used as a paint or an adhesive, the strength as a resin is insufficient. In the present invention, one of the main points is that before starting the chlorination of the polyolefin, the polyolefin is preliminarily melted and suspended in water at a temperature higher than the melting point of the polyolefin by 5 ° C. or more, and then chlorine is introduced. The state of dispersion affects the rate of chlorination and the stability of the system.

[0010] The reaction temperature of the present invention is a temperature within the range of 80 to 170 ° C, which is higher than the melting point of the polyolefin used by 5 ° C or more, preferably a temperature at which the melt viscosity of the polyolefin becomes 4000 cP or less. . More preferably, the temperature is in the range of 110 to 160 ° C. and the melt viscosity of the polyolefin used is 3000 cP or less. Here, the reaction temperature is 5 ° C. below the melting point of the polyolefin.
The reason why the temperature is set to be higher than above is to keep the melt suspension state in which the polyolefin is completely melted and good, and even if a little agglomeration is mixed, the chlorination becomes uneven and the solvent-insoluble chlorinated product is formed. Because it occurs. On the other hand, if the reaction temperature exceeds 170 ° C., it is not preferable because the steam pressure becomes too high and it becomes difficult to introduce chlorine, and there is a possibility that the thermal stability of the chlorinated product may be reduced or oxidized.

The mixing ratio of the polyolefin in water is 100
The appropriate amount is 1 to 20 parts by weight of polyolefin per part by weight. The water to be used may be ordinary industrial water, but ion exchange water is more preferable. In addition, an aqueous hydrochloric acid solution can be used, and a filtered reaction solution containing hydrochloric acid by-produced by the reaction can also be used. In this case, the hydrochloric acid concentration is preferably 20% by weight or less.

In the present invention, chlorination can be carried out in a molten suspension in water in the absence of a dispersant. However, when a polyolefin having a high melt viscosity at the reaction temperature is used or when the concentration of the polyolefin mixed in water is increased, a molten suspension state can be stabilized by adding a dispersant.

As the above-mentioned dispersant, ordinary surfactants and acrylic polymers can be used. As a surfactant,
Nonionic or anionic surfactants such as nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyalkylphenol esters, polyoxyethylene alkyl esters, sorbitan alkyl esters, ethylene oxide-propylene oxide block polymers, and alkylbenzene Sodium sulfonate, alcohol sulfate, alkylsulfonic acid, alkylallylsulfonic acid or their sodium salts , condensed naphtha
Anionic activators such as the sodium salt of sulfonic acid of len are suitable.

As the acrylic polymer, a polymer of acrylic acid or an acrylate ester, a copolymer thereof, or an alkali metal salt or an ammonium salt of the polymer or the copolymer having a molecular weight of 3,000 or more is suitable. In particular, those having 10,000 or more are preferably used. The acrylate is preferably an alkyl ester having 1 to 4 carbon atoms. Those which can be in-water-soluble or colloidal dispersion of these polymers are suitable for the present invention. Styrene polymer or stainless steel
Sulfuric acid sodium of len-maleic anhydride copolymer
It is also possible to use an anion-active styrenic polymer such as a salt in combination.

These dispersants can be used alone or as a mixture of two or more kinds. Particularly, a combination of a surfactant and an acrylic polymer is preferable. The amount of the dispersant used is suitably 2 parts by weight or less in terms of solids based on 100 parts by weight of the polyolefin. The dispersant may be preliminarily mixed with the polyolefin powder and then dispersed in water or an aqueous hydrochloric acid solution as a reaction solution. It may be a liquid.

The reaction vessel used in the present invention is chlorine,
It is a closed container that is made of a material that is resistant to hydrochloric acid and can be heated and stirred under pressure, and may be a glass-lined reaction tank with a stirrer generally used for a chlorination reaction. A circulation system using a static mixer is also effective for promoting the reaction. The slurry-like reaction product chlorinated to a predetermined chlorine content is taken out, filtered and separated into a reaction product and a reaction solution (aqueous hydrochloric acid solution). The reaction product is neutralized with an aqueous solution of caustic soda or sodium carbonate, filtered and washed with water, or repeatedly with a large amount of water.
It is washed, filtered and dried to obtain a chlorinated polyolefin product.

[0017]

According to the present invention, a chlorination reaction is carried out by suspending a molten polyolefin in water. Therefore, the polyolefin and chlorine undergo a dissolved chlorine reaction in the liquid- medium so that uniform chlorination is possible, and since the reaction is carried out at a relatively high temperature, the reaction rate is large and the reaction time is greatly reduced.

2) According to the method of the present invention, a solvent-soluble chlorinated polyolefin containing no residual crystals even with a chlorine content of 35 to 70% can be easily produced.

3) According to the method of the present invention, powdery chlorinated polyolefin can be relatively stably taken out even if the chlorine content exceeds 45%.

4) When the reaction temperature exceeds 115 ° C., the chlorination rate is remarkably accelerated. However, no coloring is observed in the products of the invention. Further, when high chlorination is to be achieved, the reaction is relatively fast even near the end point of chlorination, so that the chlorine conversion can be significantly increased as compared with low temperature chlorination.
Further, the chlorination reaction can proceed at a sufficient speed without light irradiation or addition of a radical initiator.

5) The product according to the method of the present invention has excellent heat stability and solubility in aromatic solvents and ketone solvents as compared with low-temperature chlorinated products, indicating that it is a fairly uniform chlorinated product.

6) The method of the present invention can smoothly perform high chlorination of a low molecular weight polyolefin without using an organic solvent, is more economical than the solvent method, and is advantageous in terms of environmental problems. And an excellent chlorinated product can be obtained. Thus, it can be said that the present invention is an industrially significant invention.

[0023]

The present invention will be described in detail with reference to the following examples.
Examples in percentages Ri weight der number Both average molecular weight average
Represents molecular weight. Example 1 Average molecular weight 2700, melting point 107 ° C., melt viscosity 200c
P (160 ° C), 300 cP (140 ° C), density 0.9
3, acid-modified polyethylene having an acid value of 30 (average particle size of 40
3 kg of 0 μm granules) was put into a 100-liter glass-lined pressurized reaction tank together with 65 liters of ion-exchanged water, and 3 g of a nonionic surfactant (polyoxyethylene alkylphenyl ether) and an aqueous solution of an acrylic acid polymer ( pH 2.0, molecular weight 13,000, solid content 30
%) And heated to 120 ° C. with stirring. At this temperature, the raw polyethylene is completely melted and is in a molten suspension state by stirring. Then, chlorine gas was blown in and 12
Chlorination was performed in the range of 0 ± 1 ° C. over 280 minutes to the target amount of 68%. After the completion of the reaction, when cooled, a chlorinated product was obtained in a slurry state, and a white powdery wet body was obtained by centrifugation.

This was dispersed in 5 times the volume of ion-exchanged water, neutralized with a 10% aqueous solution of NaOH, dehydrated by centrifugation, and then repeatedly washed and dehydrated with ion-exchanged water.
After the pH of the filtrate reached 6.5, it was centrifuged and dried at 70 ° C. under reduced pressure for 36 hours to obtain a white ultrafine chlorinated polyethylene.

This product had a chlorine content of 67.2% and a chlorine conversion of 98.8%. This product was rapidly dissolved in toluene to form a transparent solution, and the solution viscosity at a solid content of 20% was 8 cP (20 ° C.), and the Hazen chromaticity was 10 or less. No residual crystals were observed by DSC (differential scanning calorimeter, manufactured by Perkin Elmer Co., Ltd., heating rate 10 ° C./min).

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that the chlorination reaction was carried out at 70 ° C. for 21 hours up to a target chlorination amount of 70%, and white granules having a diameter of 2 to 3 mm were formed. I got something. The powder could be easily formed into a powder by gently rubbing it with a finger. However, in the case of dissolving in toluene, insolubles remained and cloudiness was caused by dust. The chlorine content of the product was 66.4%, and residual crystals of 0.6 cal / g were recognized by DSC.

Comparative Example 2 A test was conducted in the same manner as in Comparative Example 1 except that the reaction temperature was increased to 90 ° C. in order to increase the reaction rate.
Agglomeration occurred at a chlorination amount of 25%, and chlorination could not proceed.

Example 2 Average molecular weight: 1000, melting point: 109 ° C., melt viscosity: 10 cP
(160 ° C.), 20 kg (140 ° C.), 1 kg of low-density polyethylene having a density of 0.92 are put into a 100-liter glass-lined pressurized reaction vessel together with 75 liters of ion-exchanged water, stirred and dispersed at 125 ° C., and then melt-suspended. Chlorine gas was blown in under this condition, chlorination was performed within a range of 125 ± 1 ° C. over 240 minutes to a chlorination target amount of 69%, and after cooling, the slurry was taken out and centrifuged to obtain a white powdery wet body. This was treated in the same manner as in Example 1 to obtain a white ultrafine chlorinated polyethylene. The product has a chlorine content of 67.8%
And the chlorine conversion was 98.3%. This quickly dissolved in toluene to give a clear solution. The viscosity of the toluene solution was 45 cP (25 ° C.) at a solid content of 40%, and the Hazen chromaticity was 20.

Comparative Example 3 Chlorination was performed in the same manner as in Example 2 except that chlorine was blown in at 70 ° C. while stirring and dispersing. Agglomeration started from about 10% of the chlorination rate, and stirring was continued. The reaction was stopped because it was no longer possible.

Example 3 Average molecular weight 4000, melting point 118 ° C., melt viscosity 1100
1.5 kg of low-density polyethylene having a cP (140 ° C.) and a density of 0.95 and a dispersant liquid (2 g of a nonionic surfactant polyoxyethylene octylphenyl ether and an acrylic acid polymer (pH 2.0, molecular weight 13,000, solid content 30) %)
15 g dissolved and dispersed in 500 g of water) in advance to prepare a mixture in which both were sufficiently blended. Next, 10% was added to the glass-lined pressurized reaction tank with a capacity of 100 liter.
Add 70 liters of HCl aqueous solution, add the above mixture with stirring, raise the temperature after dispersion, blow in chlorine gas at 130 ° C in a molten and suspended state, and reach the target amount of 68% in the range of 130 ± 1 ° C over 200 minutes. Chlorination was performed. After cooling, the slurry reaction product was taken out and centrifuged to obtain a white powdery wet body.
This was dispersed in 5 times the volume of industrial water, and then stirred at 60 ° C. for 2 hours while maintaining a pH of 9 by adding a 10% aqueous NaOH solution, neutralized with hydrochloric acid, dehydrated by centrifugation, and then washed with industrial water. The dehydration was repeated three times and dried at 70 ° C. under reduced pressure for 36 hours to obtain a white fine powdered chlorinated polyethylene. This product had a chlorine content of 67.0% and a chlorine conversion of 98.5%. This product was rapidly dissolved in toluene to become a transparent liquid, the solution viscosity at a solid content of 20% was 12 cP (20 ° C.), and the Hazen chromaticity was 10.

COMPARATIVE EXAMPLE 4 In Example 3, except that after stirring and dispersing at 70 ° C., chlorine gas was blown in and chlorination was performed within a range of 70 ± 1 ° C. over 22 hours to a chlorination target rate of 71%. Tested as in Example 3, the product was treated as in Example 3 to give a white granular product. This product has a chlorine content of 66.5%,
The chlorine conversion was 93.7%. When the solubility of this product in toluene was examined, it was dispersed in toluene, but it became cloudy and did not become a transparent liquid. 0.8 cal by DSC
/ G of residual crystals was observed.

Example 4 Average molecular weight: 8000, melting point: 111 ° C., melt viscosity: 2000
cP (160 ° C.), 3000 cP (140 ° C.), 2 kg of low-density polyethylene having a density of 0.92 were placed in a 100-liter glass-lined pressurized reaction tank with deionized water 85.
Liter together with an anionic activator (ammonium salt of ether sulfate pH7.
8) 4 g and 15 g of an aqueous solution of acrylic acid polymer (pH 2.0, molecular weight 13,000, solid content 30%) were added, and 135 g was added.
After stirring and dispersing at ℃, chlorine gas is blown in a molten suspension state, chlorination is performed to a target chlorination amount of 68% in a range of 135 ± 1 ° C over 220 minutes, and after cooling, a slurry is taken out and centrifuged. A white powdery wet body was obtained. This was treated in the same manner as in Example 3 to obtain a white fine powdered chlorinated polyethylene. This product had a chlorine content of 67.3% and a chlorine conversion of 99%. This product was rapidly dissolved in toluene to form a transparent solution, and the solution viscosity at a solid content of 20% was 22 cP (20 ° C.), and the Hazen chromaticity was 20.

Comparative Example 5 The same polyethylene as in Example 4 was previously pulverized to an average particle size of 40 μm, and the same chlorination as in Example 4 was carried out under aqueous suspension at 80 ° C. for 20 hours while the chlorination target amount was 72%. After cooling, the slurry was taken out and centrifuged to obtain a white granular wet body. This wet body was treated in the same manner as in Example 4 to obtain a white powdery chlorinated polyethylene. The chlorine content of this product was 67.6%, and the chlorine conversion was 94.0%. When this product was dispersed in toluene,
Although almost dissolved, slight turbidity and insoluble matter were recognized, the solution viscosity at a solid content of 20% was 25 cP (20 ° C.), and the Hazen chromaticity was 60.

Example 5 Average molecular weight 3000, melting point 140 ° C., melt viscosity 70 cP
(160 ° C.), 2 kg of low molecular weight polypropylene powder having a density of 0.89 was put into a 100 liter glass-lined pressurized reaction vessel together with 80 liters of ion-exchanged water, and a nonionic surfactant (polyoxyethylene nonyl) was added thereto as a dispersant. 5 g of phenyl ether) and an aqueous solution of acrylic acid polymer (pH 2.0, molecular weight 13,000, solid content 30%)
After adding 15 g and stirring and dispersing at 150 ° C., chlorine gas is blown in a molten suspension state, and chlorination is performed at 150 ± 2 ° C. for 200 minutes to a chlorination target amount of 69% to give a white powdery wet substance. I got This was treated in the same manner as in Example 1 to obtain chlorinated polypropylene in the form of fine white powder. This chlorine content is 6
At 8.1%, it was rapidly dissolved in toluene to form a clear solution. The solution viscosity at a solid content of 20% was 5 cP (20 ° C.), and the Hazen chromaticity was 20.

Comparative Example 6 A test was conducted in the same manner as in Example 5 except that the mixture was stirred and dispersed at 90 ° C., and then blown with chlorine gas and reacted at 90 ± 1 ° C .. The reaction was stopped.

Example 6 Average molecular weight: 2000, melting point: 122 ° C., melt viscosity: 80 cP
(140 ° C), high density polyethylene 3k with density 0.97
g in a glass-lined pressurized reaction vessel having a capacity of 100 liters together with 80 liters of ion-exchanged water, and 6 g of a nonionic surfactant (polyoxyethylene nonylphenyl ether) as a dispersant was added thereto. Chlorine gas was blown into the suspension, and chlorination was performed over a period of 100 minutes within a range of 130 ± 1 ° C. to a target chlorination amount of 35%. After cooling, a slurry was taken out. When the chlorinated product is drained, it forms a rice cake, which is washed in ion-exchanged water at 90 ° C., and is taken out when the pH of the washing water exceeds 6;
Drying was performed at 0 ° C. under reduced pressure for 48 hours to obtain bulk chlorinated polyethylene. The product had a chlorine content of 34.4% and was dissolved in toluene to give a clear solution. A 30% solids solution had 2100 cP (25 ° C.) and Hazen chromaticity of 5 or less.

Comparative Example 7 The chlorination target rate of 3 in Example 6 at 70 ° C. for 6 hours
The reaction and treatment were carried out in the same manner as in Example 6 except that the chlorination was carried out up to 7% to obtain bulk chlorinated polyethylene. The chlorine content of this product was 34.7%, it was partially dissolved in toluene, and many insolubles remained. The residual crystal by DSC is 1
It was 0 cal / g.

Examples 7 and 8 Comparative Examples 8 and 9 The chlorinated polyethylenes obtained in Examples 1 and 4 and Comparative Examples 1 and 5 were tested for solubility in various solvents and heat resistance. It was shown to. The solubility test in the solvent
20 g of chlorinated polyethylene was added to 80 g of each of the three organic solvents of toluene, methyl ethyl ketone and ethyl acetate,
The mixture was stirred well at 20 ° C. to dissolve it, and the appearance of the solution was visually observed. The judgment results are shown by symbols on the display. The solubility of the chlorinated polyethylenes of Comparative Examples 1 and 5 in solvents was examined for toluene-insoluble precipitates which were filtered off and dried.

In the heat stability test, the powder dried at 70 ° C. under reduced pressure was again placed in a constant-temperature oven at 100 ° C. for 5 hours, and the appearance of the powder was visually observed.

[0040]

[Table 1]

Continuation of front page (56) References JP-A-50-51190 (JP, A)

Claims (2)

(57) [Claims] 1. A polyolefin having a number average molecular weight of 800 to 12,000 and a melt viscosity at 170 ° C. of 4,000 centipoise or less is used in an amount of 1 to 20 weight parts per 100 parts by weight of water.
Used amount unit, 5 ° C. from an aqueous medium NakaToru point the polyolefin
A method for producing a solvent-soluble chlorinated polyolefin, comprising chlorinating in a molten suspension state at a high temperature. 2. The method for producing a chlorinated polyolefin according to claim 1, wherein the chlorination is carried out at a temperature at which the melt viscosity of the polyolefin is 4000 centipoise or less.