JP2001247603A - Preparation method of vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a vinyl chloride-based polymer with a high productivity without generating coarse particle size and abnormal phase transition attributable to the weight ratio of an aqueous medium and a vinyl chloride-based monomer in a polymerization reactor in a charging period and abnormal polymerization and insufficient heat removal due to the high initial polymerization rate in a method to shorten the production cycle of a vinyl chloride- based polymer where the aqueous medium and the vinyl chloride monomer are charged simultaneously. SOLUTION: In preparation of a vinyl chloride-based polymer by simultaneously charging an aqueous medium which is heated and deaerated beforehand and a vinyl chloride-based monomer into a polymerization reactor to conduct suspension polymerization of the vinyl chloride-based monomer, the charging flow setting values for the heat-deaerated aqueous medium and the vinyl chloride-based monomer are regulated such that the weight ratio of the heat-deaerated aqueous medium and the vinyl chloride-based monomer in the polymerization reactor in a charging period is 0.7:1 to 1.3:1. Furthermore, when the charging flow setting values for the heat-deaerated aqueous medium and the vinyl chloride-based monomer are regulated such that the weight ratio of the charging flows of the heat-deaerated aqueous medium and the vinyl chloride-based monomer is 0.5:1 to 1.5:1, the weight ratio of the heat- deaerated aqueous medium and the vinyl chloride-based monomer in the polymerization reactor in the charging period is 0.7:1 to 1.3:1.

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 vinyl chloride polymer, and more particularly, to a method for preparing a vinyl chloride monomer and a heated degassed aqueous medium in a polymerization machine in parallel. To control the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer in the machine, control the set flow rate of the vinyl chloride monomer and the heated degassed aqueous medium to the polymerization machine. The present invention relates to a method for manufacturing a united product.

[0002]

2. Description of the Related Art Vinyl chloride resins are inexpensive and have an excellent quality balance, and are used in a wide range of fields depending on their properties. For example, hard vinyl chloride resin
Used for pipes, films, industrial boards, window frames, and the like, and soft vinyl chloride resins are used for electric wire coatings, wrap films, sheets, and the like. By the way, a vinyl chloride resin as a material is a general-purpose resin in which inexpensiveness is an essential condition, and various means for improving polymerization productivity have been conventionally employed in order to reduce the production cost. For example, a method of increasing the capacity of a polymerization machine to increase the production amount per production, a method of shortening the polymerization time by improving the heat removal ability by an external reflux condenser or an internal jacket, a vinyl chloride monomer First, then degassed hot water to reduce the temperature rise time and increase productivity.Additionally, the vinyl chloride monomer and degassed hot water are simultaneously charged in parallel. In addition, a method of increasing the productivity by shortening the heating time has been proposed.

For example, a method of simultaneously charging a vinyl chloride monomer and degassed warm water in parallel is disclosed in Japanese Patent Laid-Open No. 1-1724.
07, JP-A-5-295006, JP-A-5-295006
This is disclosed in Japanese Patent Application Laid-Open No. 0-251307, Japanese Patent Application Laid-Open No. 11-1504, and the like. However, in each publication, the relationship between the vinyl chloride monomer during the charging period and the flow rate of degassed hot water, the weight of the vinyl chloride monomer charged in the polymerization machine during the charging period, and the degassing temperature Nothing is said about the relationship of water weight. When the ratio of degassed water and vinyl chloride monomer charged in the polymerization machine during the charging period is 0.5 or less, the vinyl chloride monomer phase becomes a continuous phase, and the particle size becomes coarse and large On the contrary, if the temperature is 1.5 or more, the temperature in the polymerization machine exceeds the predetermined polymerization temperature during the charging period, and the polymerization starts, resulting in a problem of coarse particle size and scale formation. is there. JP-A-11-2174
No. 04 regulates that the ratio of degassed water and vinyl chloride monomer charged into the polymerization machine during the charging period is set to 0.8 or more. However, the upper limit and its control method are specified. Is not described.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for charging a preliminarily degassed heated aqueous medium and a vinyl chloride monomer in a polymerization machine in parallel. Provides a highly productive method for producing a vinyl chloride-based polymer that can reduce the charging time and heating time without causing abnormal polymerization such as coarse particle size or large lumps caused by the high polymerization rate. It is to be.

[0005]

Means for Solving the Problems The present inventors have intensively studied to solve the above problems in order to improve the productivity by a stable process, and as a result, adopt a specific charging condition and a charging control method. As a result, they have found that the above problems can be solved, and have completed the present invention. That is, according to the present invention, the above-mentioned object includes charging an aqueous medium previously heated and degassed and a vinyl chloride-based monomer into a polymerization machine in parallel to carry out suspension polymerization of the vinyl chloride-based monomer. Wherein the weight ratio of the heated degassed aqueous medium and the vinyl chloride monomer in the polymerization machine during the charging period is 0.7: 1 to 1.3: 1. The problem can be solved by a method for producing a vinyl chloride polymer in which the heated degassed aqueous medium and the vinyl chloride monomer are charged and the set flow rate is controlled.

In a preferred embodiment, the heated degassed aqueous medium or the vinyl chloride monomer is charged at least 20% of the total set amount, or both the heated degassed aqueous medium and the vinyl chloride monomer are used. After completion of charging at least 10% of the total set amount of each, the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer in the polymerization machine during the charging period is 0.7: 1 to 1: 1.
The control of the set flow rate of the heated degassed aqueous medium and the vinyl chloride monomer is started so that the ratio becomes 1.3: 1. Also,
By keeping one of the set amount of the heated degassed aqueous medium and the set amount of the vinyl chloride monomer constant and controlling the other set amount, the heated degassed aqueous medium and the chloride in the polymerization machine can be controlled. The weight ratio of the vinyl monomer is 0.7: 1 to 1
Maintain 1.3: 1.

In another preferred embodiment, the weight ratio of the flow rates of the heated degassed aqueous medium and the vinyl chloride monomer is 0.5: 1.
The heated degassed aqueous medium and the vinyl chloride-based monomer in the polymerization machine during the charging period are controlled by controlling the set flow rate of the heated degassed aqueous medium and the vinyl chloride-based monomer to 1.5: 1. The weight ratio of the monomers is 0.7: 1 to 1.3: 1. Also in this case, after the heating degassed aqueous medium or vinyl chloride monomer has been charged at least 20% of the total set amount, or both the heated degassed aqueous medium and the vinyl chloride monomer have been added to each. After completion of charging at least 10% of the total set amount, heating is performed so that the weight ratio of the heated deaerated aqueous medium and the charged flow rate of the vinyl chloride monomer becomes 0.5: 1 to 1.5: 1. The control of the set flow rate of the deaerated aqueous medium and the vinyl chloride monomer is started. Also, one of the heating degassed aqueous medium and the charged flow rate set value of the vinyl chloride monomer is fixed,
By controlling the other, the weight ratio of the flow rate of the heated degassed aqueous medium and the charged amount of the vinyl chloride monomer is set to 0.5: 1 to 1: 1.
Maintain 5: 1. In any case, the internal temperature of the polymerization machine at the end of the charging is preferably -20 ° C to + 5 ° C with respect to the predetermined polymerization temperature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a vinyl chloride monomer means vinyl chloride alone or a mixture of vinyl chloride and a monomer copolymerizable therewith. In the case of a mixture, the proportion of vinyl chloride is at least 50% by weight. Examples of monomers copolymerizable with vinyl chloride include vinyl acetate, vinyl esters such as vinyl propionate, ethylene, olefins such as propylene, vinyl ethers such as isobutyl vinyl ether, maleic anhydride,
Acrylonitrile, styrene and the like can be mentioned. These may be used alone or in combination of two or more.

[0009] The polymerization equipment used in the production method of the present invention comprises:
Any pressure-resistant polymerization reactor may be used. Further, the shape of the stirring device such as a stirring blade used in the polymerization reaction device and a baffle used if desired is not particularly limited, and a well-known method generally used in a suspension polymerization method of a vinyl chloride monomer has been used. Can be used.

[0010] Such stirring blades include, for example, paddle blades, blue margin blades, Faudler blades, turbine blades,
Propeller blades, pitch paddle blades and the like may be mentioned, and these stirring blades may be used singly, in combination with a plurality of stirring blades, or separately in several stages. Examples of the baffle include a plate type, a cylindrical type, a D type, a loop type, and a finger type.

[0011] The polymerization apparatus may be provided with a heating / cooling jacket or an external slurry circulation type heat exchanger. Examples of such a heating / cooling jacket include an outer jacket and an inner jacket, and examples of the outer slurry circulation type heat exchanger include a shell and tube type, a multi-tube type, a coil type, and a spiral type. . The circulation pump may be a commonly used one. Further, a reflux condenser attached to the polymerization apparatus may be used. The installation type may be any of direct and indirect by gas / condensate piping, and the type of the condenser is preferably a shell and tube type which is easy to clean. However, any of a multi-tube type, a coil type, a spiral type and the like can be used.

The capacity of the polymerization reaction vessel in the present invention is not particularly limited, but is 25 m ³ or more, preferably 35 m ³ , since a vinyl chloride polymer can be produced with high production efficiency.
As described above, it is preferable to use a polymerization reaction vessel of 60 m ³ or more. The scale inhibitor may be applied to the polymerization reaction vessel and / or incidental equipment.

The feed pipes attached to the polymerization reactor may be separate pipes for the vinyl chloride monomer and for the heated degassed aqueous medium, or may be the same pipes. When the same piping is used, the vinyl chloride-based monomer and the heated degassed aqueous medium may be charged into the polymerization machine while being mixed using a mixer such as a static mixer.

After the completion of the charging, the temperature inside the polymerization machine is raised from -20 ° C. to + 5 ° C. with respect to a predetermined polymerization temperature (generally, about 30 to about 70 ° C.)
It is preferable to adjust the temperature to within the range of ° C. In order to adjust the internal temperature of the polymerization machine in this manner, a method in which the temperature of the vinyl chloride-based monomer and / or the heated degassed aqueous medium is increased in advance, There is a method in which the temperature is started before the completion of the charging, or a method in which the temperature is started in combination, and the temperature of the heated and degassed aqueous medium is preferably 40 ° C. or higher, more preferably 50 ° C. or higher. If the temperature of the heated degassed aqueous medium is lower than that, not only does the temperature-raising equipment for raising the temperature of the polymerization system in the polymerization machine in a short time become large and the equipment cost increases, but also the temperature-raising must be started early. However, since the temperature rise is started before the suspension system in which the heated degassed aqueous medium has become a continuous phase is stabilized, polymerization occurs on the inner wall surface of the polymerization machine, and scale is formed.

When the vinyl chloride monomer and the heated degassed aqueous medium are charged in parallel, the charging may be started at the same time, or any of these may be slightly earlier, for example, for 1-2 minutes. You may start charging early.

In the present invention, the heat degassing aqueous medium in the polymerization machine during the charging period is heated and degassed so that the weight ratio of the vinyl chloride monomer becomes 0.7: 1 to 1.3: 1. The water flow medium and the vinyl chloride monomer are charged by controlling the set flow rate. For example, the set flow rate of one of the heated degassed aqueous medium and the vinyl chloride monomer is fixed, and the weight ratio of the heated degassed aqueous medium to the vinyl chloride monomer in the polymerization machine is 0.7: The other flow rate set value is controlled so as to maintain the range of 1 to 1.3: 1. In order to control the charging flow rate to be constant, ordinary PID control may be adopted. The set value of the flow rate of the heated degassed aqueous medium or the vinyl chloride-based monomer at a constant flow rate is set at an initial value of 0.7: 1 to 1 by weight ratio of the vinyl chloride-based monomer to the heated degassed aqueous medium. The flow rate is controlled in advance by a control method such as a normal PID control at this flow rate.

Preferably, at the time when 20% or more, preferably 10% or more of the total set amount of the heated degassed aqueous medium has been charged, or when both the heated degassed aqueous medium and the vinyl chloride monomer are used, At the end of charging 10% or more, preferably 5% or more of the total charging set amount of the above, the weight ratio of the heated degassed aqueous medium to the vinyl chloride monomer is 0.7: 1 to 1.3:
A value within the range of 1, preferably 0.8: 1 to 1.2: 1
, For example, about 1.0, the set value of the charged flow rate of the vinyl chloride-based monomer is automatically changed at a fixed cycle to control the charged flow rate.

According to a particularly preferred embodiment of the production method of the present invention, the weight ratio of the flow rates of the heated degassed aqueous medium and the vinyl chloride monomer is 0.5: 1 to 1.5: 1. The weight ratio between the heated degassed aqueous medium and the vinyl chloride-based monomer in the polymerization machine during the charging period is controlled by controlling the set flow rate of the heated degassed aqueous medium and the vinyl chloride-based monomer.
7: 1 to 1.3: 1. For example, the set value of the charged flow rate of either the heated degassed aqueous medium or the vinyl chloride monomer is fixed, and the weight ratio of the charged flow rates of the heated degassed aqueous medium and the vinyl chloride monomer is 0.5: 1-1.
The other flow set value is controlled to maintain a predetermined value in the range of 5: 1.

In order to control the charging flow rate to be constant, ordinary PID control may be employed as in the above case. Set the flow rate of the heated degassed aqueous medium or vinyl chloride monomer to be a constant flow rate, and set the initial set value to the weight ratio of the vinyl chloride monomer to the heated degassed aqueous medium in the polymerization machine during the charging period. The flow rate is set in advance so as to fall within a range of 0.7: 1 to 1.3: 1, and the flow rate is controlled by a control method such as a normal PID control. Preferably, 20% or more, preferably 10% or more of the total set amount of the hot degassed aqueous medium has been charged, or both the heated degassed aqueous medium and the vinyl chloride monomer have been completely charged. When 10% or more, preferably 5% or more of the set amount has been charged, the weight ratio between the heated deaerated aqueous medium and the charged flow rate of the vinyl chloride monomer is 0.5: 1.
The set value of the flow rate of the vinyl chloride-based monomer is automatically changed at regular intervals so as to be a predetermined value within the range of 1.5: 1, for example, about 1.0, and the flow rate is controlled. Perform

During the charging period, the weight ratio of the heated degassed aqueous medium charged into the polymerization machine to the vinyl chloride monomer is 0.7: 1.
If less than (that is, if the proportion of the heated degassed aqueous medium is too small), a phase change abnormality in which the vinyl chloride monomer becomes a continuous phase in the dispersion suspension occurs, and the particle size becomes coarse, Further, when it is 0.5 or less, a large lump is formed, which leads to abnormal polymerization in which polymerization becomes impossible. Conversely, when the weight ratio exceeds 1.3: 1 (that is, when the ratio of the heated degassed aqueous medium is too large), especially after the completion of the charging, the temperature in the polymerization machine is set to −20 to 20 with respect to the predetermined polymerization temperature setting. In a process where the temperature rises to + 5 ° C., the polymerization rate during the charging period exceeds the predetermined polymerization temperature, and the polymerization speed becomes extremely high in a state where the dispersion and suspension system at the initial stage of the polymerization is not stable. When formation occurs, and when the ratio becomes 1.5: 1 or more, there is a problem that formation of a large mass occurs.

The change of the set flow rate of the vinyl chloride monomer may be carried out at a cycle of 120 seconds or less, preferably at a cycle of 1 to 60 seconds, more preferably at a cycle of 2 to 30 seconds. Thereby, when a time difference is provided between the heated degassed aqueous medium and the vinyl chloride-based monomer, the heated degassed aqueous medium and the vinyl chloride-based monomer charged in the polymerization machine are removed from a predetermined weight ratio. The deviation can be corrected. For example, when the flow rate of the heated degassed aqueous medium or vinyl chloride monomer that is being charged at a constant flow rate fluctuates for some reason, for example, when the flow rate of the heated degassed aqueous medium decreases due to strainer clogging, By automatically lowering the set flow rate of the other vinyl chloride monomer, a predetermined control ratio can be maintained. When the flow rate decreases due to blockage of the pipe or the strainer in the charging of the polymerization initiator and other auxiliary materials, the charging of these auxiliary materials is completed within the charging period of the heated degassed aqueous medium and the vinyl chloride monomer. Therefore, it is necessary to reduce the flow rates of the heated degassed aqueous medium and the vinyl chloride monomer.
In such a case, conventionally, it was necessary for the operator to reset each charging flow rate, but in the case of the present invention,
For example, only by manually lowering the flow rate setting of the heated degassed aqueous medium, which is a constant flow rate, the charged flow rate of the vinyl chloride-based monomer can be automatically followed to easily and accurately cope.

In the present invention, in order to control the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer charged in the polymerization machine, the timing for starting the flow rate control of the vinyl chloride monomer is as described above. (1) After the completion of the charging of 20% or more, preferably 10% or more of the entire predetermined charged amount of the heated degassed aqueous medium or vinyl chloride-based monomer, or
(2) After the heating degassed aqueous medium and the vinyl chloride monomer have been charged at least 10%, preferably 5% or more of the total charged set amount of each. Any of the above may be used as a criterion for determining the start time of the flow rate control,
The former is sufficient when the charging of the heated degassed aqueous medium and the vinyl chloride monomer are started simultaneously. When the charging of the heated degassed aqueous medium and the vinyl chloride monomer is started earlier than the other, the latter in which the charging flow rate is stable may be desirable.

If the control of the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer in the polymerization machine is significantly slower than the time set in the above (1) or (2), the temperature in the polymerization machine may be reduced. In addition, the period in which the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer is out of the control range becomes longer, and the effect of the present invention is unfavorably reduced.

The heated degassed aqueous medium used in the present invention is water or water as a main component (50% or more of the total weight of the medium).
In particular, heated deionized water, and further, heated deionized degassed water are preferable. The temperature of the aqueous medium is
The range is preferably from 40 ° C. to 95 ° C., and more preferably from 50 ° C. to 95 ° C. in order to shorten the heating time.

As the polymerization initiator used in the present invention, those generally used conventionally as a polymerization initiator for vinyl chloride can be used. Examples of the polymerization initiator include peroxycarbonate compounds such as diisopropylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate and diethoxyethylperoxydicarbonate; t-butylperoxyneodecanoate; Cumyl peroxy neodecanoate, t-hexyl peroxy bivalate, t-amyl peroxy neodecanoate, 1,1-dimethyl-3-hydroxybutyl peroxy neodecanoate, t-hexyl peroxy diglyco Peroxyester compounds such as α-cumyl peroxyneodecanate; peroxides such as acetylcyclohexylsulfonyl peroxide; azobis (2,4-dimethylvaleronitrile) and azobis (4-methoxy-2,4-dimethyl) Azo such as valeronitrile) Compound; hydrogen peroxide. These can be used alone or in combination of two or more. The amount of the polymerization initiator used is preferably in the range of 0.001 to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer.

The method of adding the polymerization initiator to the polymerization machine may be the method employed in the conventional method for producing a vinyl chloride polymer. For example, during the charging of the aqueous medium, the polymerization initiator may be added directly into the aqueous medium or the emulsifier or the like. Add it in an emulsion state using a surfactant or a suspending agent, or make an emulsion state directly in the monomer or during the preparation of the vinyl chloride monomer using an emulsifier, a surfactant or a suspending agent. Or add
After completion of the charging, it can be charged directly or in an emulsion state.

The dispersion stabilizer used in the present invention includes:
It is not particularly limited, and may be generally used as a dispersion stabilizer during suspension polymerization of a vinyl chloride monomer. Examples of dispersants include cellulose derivatives such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxypropylethylcellulose; water-soluble polymers such as partially saponified polyvinyl alcohol, acrylic acid polymers and gelatin; nonionic surfactants and anionic surfactants And a surfactant such as an agent. These can be used alone or in combination of two or more. The amount of the dispersant used is preferably in the range of 0.01 to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer.

In the polymerization system, if necessary, a thickener, a polymerization regulator, a chain transfer agent, a pH regulator, a gelling improver, an antistatic agent, and the like, which are appropriately used in the polymerization of the vinyl chloride monomer, Crosslinking agents, stabilizers, fillers, antioxidants, buffers, scale inhibitors, and the like can be added as desired.

[0029]

EXAMPLES The present invention will be described below based on examples and comparative examples, but the present invention is not limited to these examples. In the following, “parts” is “parts by weight”. The content of coarse particles of 60 mesh or more was measured as follows. After drying the resin obtained by polymerization, 100 g of the resin was sieved through a 60-mesh sieve, the amount of resin on the sieve was weighed, and the ratio (% by weight) of the amount of resin on the sieve to the total amount of resin was calculated.

Example 1 After degassing a stainless steel polymerization reactor (capacity: 30 m ³ ) equipped with a condensing reflux condenser, 10 tons of deionized hot water at 75 ° C. and vinyl chloride monomer at 20 ° C. were degassed in advance. 10 tons were added to the reaction vessel, and 0.07 part of partially saponified polyvinyl alcohol (based on 100 parts of vinyl chloride monomer) (degree of saponification 80 mol%, degree of polymerization 2000), t-butylperoxy neodecano 0.020 parts of Eat, and 3,5,5
Suspension polymerization was carried out in the presence of 0.025 parts of trimethylhexanoyl peroxide. The charging of the heated degassed water and the vinyl chloride monomer was simultaneously started at a rate of 50 tons / h each. When the charging of 1.0 ton of hot water is completed, the flow rate setting value of the vinyl chloride monomer is set so that the weight ratio of the vinyl chloride monomer to the hot water in the reaction vessel becomes 1.0: 1. Started control. The control cycle was one minute. The temperature after completion of the charging was 62 ° C., which was lower by 2 ° C. than the predetermined polymerization temperature of 64 ° C. As a result, the weight ratio of hot water and vinyl chloride monomer in the reaction vessel over the entire charging period was 1.0: 1,
The temperature inside the container was also kept at 62 ° C., and the content of coarse particles in the obtained vinyl chloride resin was 0.05% by weight.

Example 2 Polymerization was carried out in the same manner as in Example 1 except that the charging of hot water was started two minutes after the start of the charging of the vinyl chloride monomer. 4.0 minutes after the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine exceeded 0.7: 1, and the internal temperature was 58.
It is higher than 5 ° C and is 1
The charging was finished after 3.5 minutes. The period during which the weight ratio of hot water to monomer during the charging period exceeds 0.7: 1 corresponds to 70% of the total charging period. The coarse particle content of the obtained vinyl chloride resin was 0.1% by weight.

Example 3 The charging of vinyl chloride monomer was started 2 minutes after the start of charging of hot water, and the weight ratio of hot water to vinyl chloride monomer in the reaction vessel was 1.0: 1. The control of the flow rate set value of the vinyl chloride monomer performed in step 1 is performed for both hot water and the vinyl chloride monomer.
The procedure was started except that 0 tons were charged at a time, and the flow rate of hot water was reduced to 40 tons / h when 5 tons of hot water was charged to imitate the occurrence of troubles such as strainer clogging. Polymerization was carried out as in Example 1. . As a result, 4.0 minutes after the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine was less than 1.3: 1, the internal temperature was lower than 65 ° C., and The charging was completed 14.0 minutes after the start of charging of the monomer. The period during which the weight ratio of hot water to monomer during the charging period was less than 1.3 and the internal temperature was lower than 65 ° C. was 71% of the total charging period. The coarse particle content of the obtained vinyl chloride resin was 0.5% by weight.

Comparative Example 1 The vinyl chloride monomer was started to be charged 4 minutes after the start of the hot water charging, and charged without controlling the weight ratio of the hot water to the vinyl chloride monomer in the reaction vessel. The polymerization was carried out in the same manner as in Example 1. As a result, after 13.0 minutes from the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine was less than 1.3: 1, the internal temperature was lower than 65 ° C., and The charging was completed 15.5 minutes after the start of the charging of the monomer. The weight ratio of hot water to monomer during the charging period is 1.3:
The period in which the internal temperature was lower than 65 ° C. was only 16% of the total preparation period, and the high-temperature and unstable phase state was prolonged. The coarse particle content of the obtained vinyl chloride resin is
It was 5.5% by weight.

Comparative Example 2 Hot water was charged 4 minutes after the start of charging the vinyl chloride monomer, and the hot water was heated so that the weight ratio of hot water to the vinyl chloride monomer in the reaction vessel became 1.0. The polymerization was carried out in the same manner as in Example 1 except that the control of the set value of the flow rate of water was started when the charged amount of hot water became 3.0 tons. As a result, after 10.0 minutes from the start of charging the vinyl chloride monomer, the ratio of hot water to the monomer in the polymerization machine exceeded 0.7, the internal temperature became higher than 59 ° C, and the charging of the vinyl chloride monomer was started. Charging was completed 15.5 minutes after the start. The weight ratio of hot water to monomer during the charging period is 0.7
Only 35% of the total preparation period. The coarse particle content of the obtained vinyl chloride resin was 4.0% by weight.

Example 4 After degassing the same polymerization reaction vessel used in Example 1, 10 tons of deionized hot water of 75 ° C. and 20
Add 10 tons of vinyl chloride monomer at ℃ to the reaction vessel,
(Based on 100 parts of vinyl chloride monomer) Partially saponified polyvinyl alcohol (degree of saponification: 80 mol%, degree of polymerization: 200
0) Suspension polymerization was carried out in the presence of 0.07 parts, 0.020 parts of t-butylperoxyneodecanoate and 0.025 parts of 3,5,5-trimethylhexanoyl peroxide. Preparation of heated deaerated water and vinyl chloride monomer
The charging was started simultaneously at a speed of 50 tons / h each. The flow rate of the hot water is fixed at the initial setting, and when the hot water has been charged 1.0 ton, the weight ratio of the flow rate of the hot water to the flow rate of the vinyl chloride monomer becomes 1.0: 1. Thus, the control of the flow rate set value of the vinyl chloride monomer was started. The control cycle is 1
Minutes. The temperature after completion of the charging was 62 ° C., which was lower by 2 ° C. than the predetermined polymerization temperature of 64 ° C. As a result, the weight ratio of hot water to the vinyl chloride monomer in the reaction vessel was 1.0: 1 over the entire charging period, the temperature in the reaction vessel was also maintained at 62 ° C., and the crude vinyl chloride resin obtained was The grain content is 0.05% by weight
Met.

Example 5 Polymerization was carried out in the same manner as in Example 4, except that the charging of hot water was started 2 minutes after the start of charging the vinyl chloride monomer. As a result, 5.5 minutes after the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine exceeded 0.7, the internal temperature became higher than 58 ° C., and 14.5 minutes later. The preparation was finished. The period in which the weight ratio of hot water to monomer during the charging period exceeds 0.7: 1 corresponds to 62% of the total charging period. The coarse particle content of the obtained vinyl chloride resin was 0.1% by weight.

Example 6 The initial flow rate of the hot water was set at 50 tons / h and the flow rate of the vinyl chloride monomer was set at 60 tons / h, and the feed of the vinyl chloride monomer was started two minutes after the start of the hot water feed. Then, when the hot water and the vinyl chloride monomer are charged by 1.0 ton each, control is performed such that the weight ratio of the flow rate of the hot water charge to the flow rate of the vinyl chloride monomer is 0.8: 1. Start, and when the supply of hot water is reduced to 40 tons / h at the time when 5 tons of hot water has been charged to imitate the occurrence of trouble such as strainer clogging,
Polymerization was carried out in the same manner as in Example 4. As a result, 4.0 minutes after the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine was less than 1.3: 1, the internal temperature was lower than 65 ° C., and 13.5. After a minute the preparation was finished. The period during which the weight ratio of hot water to monomer during the charging period was less than 1.3: 1 and the internal temperature was lower than 65 ° C. was 70% of the total charging period. The coarse particle content of the obtained vinyl chloride resin is 0.4
% By weight.

Comparative Example 3 The vinyl chloride monomer was started to be charged 4 minutes after the start of hot water charging, and charged without controlling the weight ratio of the hot water charging flow rate to the vinyl chloride monomer charging flow rate. Otherwise, polymerization was carried out in the same manner as in Example 4. As a result, after 13.0 minutes from the start of charging the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine was less than 1.3, the internal temperature was lower than 65 ° C, and
After 5.5 minutes, charging was completed. During the charging period, the weight ratio of hot water to monomer was 1.3: 1 or less, and the period when the internal temperature was lower than 65 ° C. was only 16% of the total charging period, and the temperature was high and the phase was unstable. Became longer. The coarse particle content of the obtained vinyl chloride resin was 5.5% by weight.

Comparative Example 4 Hot water charging was started 4 minutes after the start of the vinyl chloride monomer charging, and when the hot water charging amount reached 3.0 tons, the hot water charging flow rate was compared with the vinyl chloride. The polymerization was carried out in the same manner as in Example 4, except that the control of the set value of the flow rate of the hot water was started so that the weight ratio of the charged flow rates of the monomers was 1.2: 1. As a result, 10.5 minutes after the start of the charging of the vinyl chloride monomer, the weight ratio of hot water to the monomer in the polymerization machine exceeded 0.7: 1, the internal temperature became higher than 59 ° C., and 15.5. Minutes later, the preparation was completed. The weight ratio of hot water to monomer during the charging period is 0.7: 1
Only 32% of the total preparation period. After 13 minutes, the charging of the vinyl chloride monomer had already been completed, and the weight ratio of hot water to the monomer did not reach 1.0: 1 until the end of the charging. The coarse particle content of the obtained vinyl chloride resin was 4.5% by weight.

Comparative Example 5 Initially, the flow rate of hot water was set at 50 tons / h and the flow rate of the vinyl chloride monomer was set at 40 tons / h. The hot water and the vinyl chloride monomer are charged without controlling the weight ratio of the charged flow rate, and the hot water is charged when 3 tons of hot water has been charged to simulate the occurrence of troubles such as strainer clogging. Flow rate 40
Polymerization was carried out in the same manner as in Example 4 except that the polymerization rate was reduced to tons / h. As a result, from the start of charging the vinyl chloride monomer, 9.
After 0 minute, the weight ratio of hot water to monomer in the polymerization machine was 0.7: 1.
, The internal temperature became higher than 59 ° C, and the charging was completed after 17.5 minutes. The hot water to monomer weight ratio during the charge period exceeded 0.7: 1 was only 37% of the total charge period. After 15 minutes, the charging of the vinyl chloride monomer had already been completed, and the weight ratio of hot water to the monomer did not reach 1.0: 1 until the charging was completed. The coarse particle content of the obtained vinyl chloride resin was 4.9% by weight.

[0041]

According to the present invention, there is a problem in processing when an aqueous medium and a vinyl chloride monomer are charged in parallel, that is, particle size coarseness, abnormal phase conversion, and high initial polymerization rate. It is possible to produce a highly productive vinyl chloride-based polymer without causing abnormal polymerization occurring in the process.

Claims (9)

[Claims] 1. A vinyl chloride-based polymer comprising charging an aqueous medium previously heated and degassed and a vinyl chloride-based monomer in a polymerization machine in parallel and subjecting the vinyl chloride-based monomer to suspension polymerization. In the method for producing a coalesced product, the weight ratio between the heated degassed aqueous medium and the vinyl chloride monomer in the polymerization machine during the charging period is 0.1%.
A method for producing a vinyl chloride-based polymer to be charged by controlling the set flow rate of the heated degassed aqueous medium and the vinyl chloride-based monomer so as to be 7: 1 to 1.3: 1. 2. After the heating degassed aqueous medium or vinyl chloride monomer has been charged at least 20% of the total charged set amount,
The heated degassed aqueous medium and the vinyl chloride-based monomer are added such that the weight ratio of the heated degassed aqueous medium and the vinyl chloride monomer in the polymerization machine during the charging period is 0.7: 1 to 1.3: 1. The method for producing a vinyl chloride-based polymer according to claim 1, wherein the body is charged by controlling a set flow rate of the body. 3. After the heating degassed aqueous medium and the vinyl chloride-based monomer have been charged in at least 10% of the total set amount of each, the heated degassed aqueous medium and the chloride in the polymerization machine during the charging period. The weight ratio with the vinyl monomer is 0.7: 1 to 1.3: 1.
The method for producing a vinyl chloride-based polymer according to claim 1, wherein the charged amount of the heated degassed aqueous medium and the vinyl chloride-based monomer is controlled so as to satisfy the following conditions. 4. A set amount of the heated degassed aqueous medium and a set amount of the heated degassed aqueous medium so that the weight ratio of the heated degassed aqueous medium to the vinyl chloride monomer in the polymerization machine is 0.7: 1 to 1.3: 1. The method for producing a vinyl chloride-based polymer according to any one of claims 1 to 3, wherein one of the set amounts of the vinyl chloride-based monomer is fixed and the other set amount is controlled. 5. A heated degassed aqueous medium and a vinyl chloride-based monomer such that the weight ratio of the flow rates of the heated degassed aqueous medium and the vinyl chloride monomer is 0.5: 1 to 1.5: 1. The weight ratio between the heated degassed aqueous medium and the vinyl chloride-based monomer in the polymerization machine during the charging period was controlled by controlling the set flow rate of the body.
The method for producing a vinyl chloride polymer according to claim 1, wherein the ratio is 7: 1 to 1.3: 1. 6. After the heating degassed aqueous medium or the vinyl chloride monomer has been charged at least 20% of the total charged set amount,
Set the flow rate of the heated degassed aqueous medium and the vinyl chloride monomer so that the weight ratio of the charged flow rates of the heated deaerated aqueous medium and the vinyl chloride monomer is 0.5: 1 to 1.5: 1. The method for producing a vinyl chloride polymer according to claim 5, wherein the value is controlled. 7. After the heating degassed aqueous medium and the vinyl chloride monomer have been charged in at least 10% of the total set amount of each, the heating degassed aqueous medium and the vinyl chloride monomer are charged. 6. The vinyl chloride-based material according to claim 5, wherein a set flow rate of the heated deaerated aqueous medium and the vinyl chloride-based monomer is controlled so that the weight ratio of the flow rates is 0.5: 1 to 1.5: 1. A method for producing a polymer. 8. The heated degassed aqueous medium and the vinyl chloride-based monomer such that the weight ratio of the charged flow rates of the heated degassed aqueous medium and the vinyl chloride monomer is 0.5: 1 to 1.5: 1. The method for producing a vinyl chloride-based polymer according to any one of claims 5 to 7, wherein one of the set flow rates of the monomer is fixed and the other is controlled. 9. Temperature in the polymerization machine at the end of charging (t ° C.)
Is T-20 ≦ t ≦ T + with respect to a predetermined polymerization temperature (T ° C.).
The method for producing a vinyl chloride polymer according to any one of claims 1 to 8, which is charged so as to be 5.