JP4416891B2 - Polymer production method and polymerization machine - Google Patents

Description

【００３７】
以上のように、本発明は従来の方法（比較例１）に比較して、塩化ビニル単量体の仕込み配管内で生成するスケールを防止でき、フィッシュアイも少ない事が判る。洗浄量が配管容量より少ない比較例２は配管容量以上で洗浄を行なった実施例１，２と比較して効果が十分でないことが判る。
【００３８】
また、洗浄を配管容量２倍以上で実施した実施例１は、配管容量と等量で洗浄を行なった実施例２より、その効果はより顕著であることが判る。
【００３９】
【発明の効果】
以上の如く、本発明によれば塩化ビニル単量体の仕込み配管部のスケール生成を防止し、フィッシュアイの発生など品質上の問題を生じることなく、生産性の高い塩化ビニル系重合体を製造できるので、その工業的価値は極めて高い。
【図面の簡単な説明】
【図１】図１は、予熱脱気水、単量体の仕込みラインを有する本発明で用いられる重合機の例である。
【符号の説明】
１ 重合機
２ 洗浄用切り替え弁
３、４ 単量体仕込み弁
５、６ 予熱脱気水仕込み弁
７ 単量体仕込みポンプ
８ 予熱脱気水仕込みポンプ[0001]
BACKGROUND OF THE INVENTION
The present invention is an improved polymerization method for a polymerizable monomer such as a vinyl chloride monomer, and more specifically, it prevents the generation of scale in the piping for charging the polymerizable monomer, and produces a polymer of good quality. The present invention relates to a polymerization method and a polymerization machine that can be obtained at a high level.
[0002]
[Prior art]
Since vinyl chloride resin is inexpensive and excellent in quality balance, it is used in various fields such as soft field and hard field. For example, it is used for electric wire coating materials, wrap films, sheets, etc. in the soft field, and for pipes, window frame molding, film applications, etc. in the hard field.
[0003]
On the other hand, it is important that a general-purpose resin such as a vinyl chloride resin as a material can be supplied at low cost, and various means for improving polymerization productivity have been conventionally attempted to reduce the manufacturing cost. For example, by increasing the capacity of the polymerization machine to increase the production volume per production, by adding the vinyl chloride monomer first, followed by charging degassed warm water (hereinafter preheated degassed water) A method to increase productivity by shortening the temperature rise time, and a method to increase productivity by shortening the charge time and temperature rise time by charging the vinyl chloride monomer and preheated deaerated water in parallel are proposed. ing.
[0004]
For example,
(1) In Japanese Examined Patent Publication No. 62-39601, an aqueous medium (a mixture in which a dispersant is dissolved in water) preheated and a homogeneous mixture of a vinyl chloride monomer and an initiator are charged simultaneously. A method to increase productivity by shortening the warm-up time,
(2) In Japanese Examined Patent Publication No. 60-26488, there is a slight time difference in the charging timing of water in which the total amount of the dispersant is dissolved and the vinyl chloride monomer in which the total amount of the initiator is dissolved. A method to increase productivity by reaching a predetermined temperature,
(3) In JP-A-60-158207, a vinyl chloride monomer containing an initiator and water containing a dispersant are premixed at 50 ° C. or less, and this mixture is reacted in a heat exchanger. A method of charging the polymerization machine while raising the temperature to the temperature,
(4) Japanese Patent Laid-Open No. 1-172407, the weight ratio at least with charged with 20% water of a vinyl chloride monomer in the polymerization machine dispersant in charge of vinyl chloride monomer is 1. A method of charging the entire amount of initiator between 5 and below is disclosed.
[0005]
However, in this way, in the method in which the preheated degassed water and the vinyl chloride monomer are charged in parallel, the side opposite to the valve polymerization machine directly connected to the polymerization machine of the vinyl chloride monomer pipe is used. There was a new problem that the vinyl chloride monomer was polymerized in the pipe part of the pipe, and the scale gradually adhered to the inner wall to increase the fish eye, eventually leading to blockage.
[0006]
For this reason, methods for preventing scale adhesion are disclosed in, for example, (5) JP-A No. 54-107991, JP-B No. 57-11561, JP-A No. 55-54305, JP-A No. 53-47486, and the like. A method has been proposed in which a scale inhibitor is applied to a pipe and dried to form a coating film. However, these methods have poor sustainability and need to be frequently applied and dried with a scale inhibitor, which not only reduces productivity, but also causes a black foreign substance containing the scale inhibitor to be obtained by polymerization. There is a problem that it is mixed in the vinyl polymer and the quality is lowered.
[0007]
Further, (6) a method and polymerizer valve directly connected to polymerizer to seal the opposite side of an inert liquid or inert gas (JP 60-223809) discloses, according to this There is a disadvantage that a new process such as a nozzle, a valve and the like for sealing and a new process of sealing are necessary, and the equipment and the process become complicated.
[0008]
[Problems to be solved by the invention]
The object of the present invention is to prevent the generation of scale in the piping section of the vinyl chloride monomer, and to prevent the generation of fish eyes and the like in the method of charging the vinyl chloride monomer and preheated degassed water in parallel. It is an object of the present invention to provide a production method and a polymerization machine for obtaining a vinyl chloride polymer having high productivity without causing the above problems.
[0009]
[Means for Solving the Problems]
The method for producing a polymer of the present invention has a preheated degassed water charging pipe and a polymerizable monomer charging pipe made of a vinyl chloride monomer , which are independently connected to a polymerization machine, upon a polymerizable monomer is polymerized in an aqueous medium using a polymerization apparatus in which the polymerizable monomer feed pipe and the preheating deaerated water were charged pipes are connected through a switching valve, the preheating degassed water wherein the polymerizable monomer were charged into the polymerizer in parallel through each feed pipe of the said after charging of the polymerizable monomer is finished, the preheating deaerated water were charged pipes the polymerizable monomer and The switching valve is switched so as to communicate with body charging piping, and the polymerizable monomer charging piping is washed with the preheated deaerated water equal to or more than the piping capacity to perform polymerization.
Polymerizer of the present invention includes a preheating degassed water, and parallel with preheated degassed water were charged pipe for charged into the polymerizer and a polymerizable monomer consisting of vinyl chloride monomer through each feed pipe polymerization Having a polymerizable monomer feed pipe, they are independently connected to a polymerization machine, the preheated degassed water feed pipe and the polymerizable monomer feed pipe are connected via a switching valve, and the polymerization After the charging of the polymerizable monomer is completed, the switching valve is switched so that the preheated degassed water charging pipe communicates with the polymerizable monomer charging pipe, and the polymerizable monomer charging pipe is connected to the pipe. A means for cleaning with the preheated deaerated water equal to or larger than the volume is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The invention of vinyl chloride in the opposite pipe section to the polymerizer valve directly connected to the monomer pipe of the polymerization machine such as a vinyl chloride were charged pipe portion of the polymerizable monomer by washing with an inert liquid The monomer is heated and polymerized (hereinafter referred to as thermal polymerization) to prevent the scale from adhering to the inner wall.
[0011]
In the present invention, water washing using a preheating degassed water. Using preheated degassed water for washing is not only effective for improving productivity without extending the time to reach the predetermined polymerization temperature from the start of charging, but also preheating degassed water and washing water used for charging. Can be used from a common storage tank, so the equipment can be simplified.
[0012]
The amount of cleaning water used in the present invention varies depending on the diameter and length of the pipe for cleaning, but the object of the present invention can be achieved as long as it is equal to or larger than the capacity of the pipe for cleaning. More than twice the capacity is good.
[0013]
As the cleaning method of the present invention, for example, when the polyvinyl chloride monomer and preheated degassed water supply pipes are directly connected to the polymerization apparatus , pipes connecting the supply pipes in the middle of the pipes, It provided a switching valve, in the wash and the pipe line through which a preheated degassed water after charging of vinyl chloride monomer is completed by switching the vinyl chloride monomer side.
[0014]
The preheated degassed water used in the present invention is deoxygenated industrial hot water, preferably ion-exchanged water, and these are produced by a known method. The temperature of the preheated degassed water may be determined in relation to the charged amount, the temperature of the vinyl chloride monomer, the charged amount, and the polymerization temperature. The preheated degassed water temperature is controlled to a predetermined temperature using a tank, heat exchanger or the like.
[0015]
The vinyl chloride monomer used in the present invention can be used at room temperature, but may be used after being heated in a tank, a heat exchanger or the like. In that case, it is preferable to use at 50 degrees C or less. If it is used at a temperature exceeding 50 ° C., scale may be generated in the tank or heat exchanger.
[0016]
The present invention can be widely used in each polymerization method of suspension polymerization, micro suspension polymerization, and emulsion polymerization, and can be applied to polymerization of vinyl chloride resin, polystyrene resin, (meth) acrylic resin, etc. It is preferably used for polymerization of vinyl chloride resin.
[0017]
The removal of the polymerization reaction heat is conventional heat removal system, for example the heat removal due to the polymerization machine jacket or inner jacket also may be controlled polymerization reaction with heat removal due reflux condenser.
[0018]
In the present invention, the charging ratio of the water / vinyl chloride monomer charged into the polymerization machine is not particularly limited, but is in the range of 0.6 / 1 to 2/1, preferably 0.8 / 1 to 1.4 / 1. .
[0019]
Examples of other monomers that can be copolymerized with the vinyl chloride monomer in the present invention include olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl stearate, methyl acrylate, and methyl methacrylate. (Meth) acrylic acid esters such as maleic acid or fumaric acid or esters thereof and acid anhydrides, nitrile compounds such as acrylonitrile, vinylidene chlorides such as vinylidene chloride, etc. Two or more types are used in combination.
[0020]
As the polymerization initiator used in the present invention, an oil-soluble initiator or a water-soluble initiator usually used in the polymerization of vinyl chloride is used. Examples of the oil-soluble initiator include lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxypivalate, t-butyl peroxyneodecanate, diisopropyl peroxydicarbonate, and G 2-. Organic peroxides such as ethylhexylperoxydicarbonate and acetylcyclohexylsulfonyl peroxide, and azo compounds such as α, α'-azobisisobutyronitrile, α, α'-azobis2,4-dimethylvaleronitrile These are used alone or in combination of two or more. Examples of the water-soluble initiator include ammonium persulfate, potassium persulfate, and hydrogen peroxide, which are appropriately selected according to the polymerization method.
[0021]
The dispersant used for the suspension polymerization in the present invention may be a known dispersant such as partially saponified polyvinyl acetate, vinyl acetate-maleic anhydride copolymer, styrene-maleic anhydride copolymer, polyvinylpyrrolidone. , Gelatin, starch, methylcellulose, hydroxypropylcellulose and the like, and these may be used alone or in combination of two or more. The emulsifier used in the micro suspension polymerization and emulsion polymerization may be a known emulsifier, for example, anionic surfactants such as sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, fatty acid soda, and the like. Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, (polyoxy) sorbitan fatty acid ester and the like can be used, and these can be used alone or in combination of two or more.
[0022]
Furthermore, there are no known techniques such as molecular weight regulators, pH regulators, gelling modifiers, antistatic agents, emulsifiers, stabilizers, scale inhibitors, etc. that are conventionally used for polymerization or copolymerization of vinyl chloride monomers. It can be used arbitrarily without hindrance, and the amount used can also follow a conventionally known method.
[0023]
In addition, polymerization initiators, dispersants , emulsifiers, molecular weight regulators, pH regulators, gelling agents, antistatic agents, scale inhibitors, etc. used in the polymerization reaction are first added to the polymerization reaction system all at once. In addition, it can be added in portions during the polymerization reaction.
[0024]
Although the polymerization reaction temperature in this invention is not specifically limited, Usually, it is 40-75 degreeC.
[0025]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples of vinyl chloride polymers and comparative examples, but the present invention is not limited thereto. In the following examples, “parts” represents parts by weight and “%” represents percent by weight unless otherwise specified.
[0026]
The characteristic value of the obtained vinyl chloride polymer was measured by the following method.
(1) After adding 50 parts of dioctyl phthalate, 3 parts of tribasic lead sulfate, 1 part of stearic acid, and 0.02 part of carbon black to 100 parts of fisheye vinyl chloride polymer, the surface temperature is increased. The mixture was charged and kneaded into an 8-inch roll adjusted to 140 ° C., and a roll sheet having a thickness of 0.3 mm was cut out in 8 minutes. The number of transparent particles observed in an area of 100 cm ² on the surface of the collected roll sheet was counted and shown.
[0027]
Example 1
Preheating degassed water as shown in FIG. 1, has a charge line of vinyl chloride monomer, a stainless steel polymerizer in an inner volume of 1700L stirrer attached piping Contents closed with valves 2-4 is 10L Was evacuated with a vacuum pump, and 670 L of preheated deaerated water whose temperature was adjusted at 65 ° C. was opened. The pump 8 was started and the second valve was closed. I started charging in minutes. At the same time, 610 L of vinyl chloride monomer at 25 ° C. was started up at the pump 7 and the third valve and the fourth valve were opened and charging was started at 32 L / min. At the same time when the vinyl chloride monomer was charged, a 5% aqueous solution of partially saponified polyvinyl acetate having a degree of polymerization of 2000 and a degree of saponification of 78 mol% was added from a side pipe connected to the line between the fifth valve and the sixth valve, although not shown. It took 5 minutes. The amount of partially saponified polyvinyl acetate charged was 0.07 parts with respect to 100 parts of vinyl chloride monomer. Similarly, the vinyl chloride monomer is charged from the side pipe connected to the line between the third valve and the fourth valve, and at the same time, about 3% of a 50% toluene solution in which di-2-ethylhexyl peroxydicarbonate is dissolved is added. Prepared in minutes. The amount of di-2-ethylhexyl peroxydicarbonate used was 0.04 part with respect to 100 parts of vinyl chloride monomer. The stirrer was started as soon as the vinyl chloride monomer was charged. In about 19 minutes, the charging of the vinyl chloride monomer was completed, the third valve and the fourth valve were closed, and the pump 7 was stopped. When the remaining amount of preheated degassed water reaches 20L, close the 6th valve, open the 2nd valve and the 4th valve, and wash the vinyl chloride monomer charged piping with preheated degassed water. I did it. After washing with 20 L of preheated degassed water, the valves were closed in the order of the fourth valve, the second valve, and the fifth valve, and the pump 8 was stopped to complete the preparation.
[0028]
Next, the temperature is adjusted by the jacket so that the internal temperature becomes 57 ° C., polymerization is performed at 57 ° C., and the polymerization is completed by recovering unreacted monomers when the internal pressure of the polymerization machine drops 0.1 MPa from the steady pressure. did. The obtained slurry was dehydrated and dried to obtain a vinyl chloride polymer.
[0029]
The same operation was performed once a day, and the state of the vinyl chloride monomer charging pipe was observed every month, and the fish eye of the vinyl chloride polymer was examined.
[0030]
(Example 2)
The same procedure as in Example 1 was performed except that the cleaning amount of the pipe for introducing vinyl chloride monomer in Example 1 was changed to 10 L.
[0031]
(Comparative Example 1)
Preheating degassed water as shown in FIG. 1, has a charge line of vinyl chloride monomer, a stainless steel polymerizer in an inner volume of 1700L stirrer attached piping Contents closed with valves 2-4 is 10L Was evacuated with a vacuum pump, and 670 L of preheated deaerated water whose temperature was adjusted at 65 ° C. was opened. The pump 8 was started and the second valve was closed. I started charging in minutes. At the same time, 610 L of vinyl chloride monomer at 25 ° C. was started up at the pump 7 and the third valve and the fourth valve were opened and charging was started at 32 L / min. At the same time when the vinyl chloride monomer was charged, a 5% aqueous solution of partially saponified polyvinyl acetate having a degree of polymerization of 2000 and a degree of saponification of 78 mol% was added from a side pipe connected to the line between the fifth valve and the sixth valve, although not shown. It took 5 minutes. The amount of partially saponified polyvinyl acetate charged was 0.07 parts with respect to 100 parts of vinyl chloride monomer. Also, at the same time as the start of charging the vinyl chloride monomer, a 50% toluene solution in which di-2-ethylhexyl peroxydicarbonate was dissolved in about 3 minutes from the side pipe connected to the line between the third valve and the fourth valve. Prepared. The amount of di-2-ethylhexyl peroxydicarbonate used was 0.04 part with respect to 100 parts of vinyl chloride monomer. The stirrer was started as soon as the vinyl chloride monomer was charged. In about 19 minutes, the charging of the vinyl chloride monomer was completed, the third valve and the fourth valve were closed, and the pump 7 was stopped. In about 20 minutes, the preparation of the preheated degassed water was completed, and the sixth valve and the fifth valve were closed and the pump 8 was stopped to complete the preparation.
[0032]
Next, the temperature is adjusted by the jacket so that the internal temperature becomes 57 ° C., polymerization is carried out at 57 ° C., and when the internal pressure of the polymerization machine falls by 0.1 MPa from the steady pressure, the unreacted monomer is recovered and the polymerization is completed. did. The obtained slurry was dehydrated and dried to obtain a vinyl chloride polymer.
[0033]
The same operation was performed once a day, and the vinyl chloride monomer charging pipe and the fish eye of the vinyl chloride polymer were examined every month.
[0034]
(Comparative Example 2)
The same procedure as in Example 1 was carried out except that the amount of cleaning of the piping for introducing vinyl chloride monomer in Example 1 was changed to 5L.
[0035]
The results are shown in Table 1.
[0036]
[Table 1]

[0037]
As described above, it can be seen that the present invention can prevent scales generated in the vinyl chloride monomer charging piping and has fewer fish eyes compared to the conventional method (Comparative Example 1). It can be seen that Comparative Example 2 in which the cleaning amount is smaller than the pipe capacity is not sufficiently effective as compared with Examples 1 and 2 in which cleaning was performed with the pipe capacity or more.
[0038]
Moreover, it turns out that the effect is more remarkable in Example 1 which implemented washing by the pipe capacity of 2 times or more than Example 2 which performed washing by the same amount as the pipe capacity.
[0039]
【The invention's effect】
As described above, according to the present invention, the production of a vinyl chloride polymer having high productivity is prevented without causing the generation of scale in the piping section of the vinyl chloride monomer and without causing quality problems such as the generation of fish eyes. since the cut in the concrete, its industrial value is extremely high.
[Brief description of the drawings]
FIG. 1 is an example of a polymerization machine used in the present invention having preheated degassed water and a monomer charging line.
[Explanation of symbols]
1 polymerizer 2 cleaning switching valve 3,4 monomer feed valve 5,6 preheated degassed water were charged valve 7 monomer feed pump 8 preheated degassed water were charged pump

Claims (5)

A preheated degassed water feed pipe and a polymerizable monomer feed pipe made of a vinyl chloride monomer are connected to a polymerization machine independently, and the preheated degassed water feed pipe and the polymerization When polymerizing a polymerizable monomer in an aqueous medium using a polymerization machine to which a polymerizable monomer charging pipe is connected via a switching valve,
Were charged and the polymerizable monomer and the preheating deaerated water to said polymerizer in parallel through each feed pipe of said,
After the preparation of the polymerizable monomer is completed, the switching valve is switched so that the preheated degassed water preparation pipe communicates with the polymerizable monomer preparation pipe, and the polymerizable monomer preparation pipe is A method for producing a polymer, wherein the polymerization is carried out by washing with the preheated degassed water equal to or more than the pipe capacity.   The method for producing a polymer according to claim 1, wherein the preheated deaerated water is deoxygenated industrial warm water. The method for producing a polymer according to claim 1 , wherein the vinyl chloride monomer is heated to normal temperature or 50 ° C or lower. The charging ratio of the preheated degassed water / vinyl chloride monomer charged to the polymerization machine, method for producing a polymer according to claim 1 in the range of 0.6 / 1-2 / 1. Preheating deaeration water charging pipe and polymerizable monomer charging pipe for feeding preheating deaerated water and a polymerizable monomer comprising a vinyl chloride monomer into the polymerizer in parallel through each charging pipe They are independently connected to the polymerization machine, the preheated degassed water feed pipe and the polymerizable monomer feed pipe are connected via a switching valve,
After the preparation of the polymerizable monomer is completed, the switching valve is switched so that the preheated degassed water preparation pipe communicates with the polymerizable monomer preparation pipe, and the polymerizable monomer preparation pipe is A polymerization machine comprising a means for cleaning with the preheated degassed water equal to or more than the pipe capacity.

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