KR20100084405A - Method for preparing polyvinylacetate using static mixer - Google Patents

Abstract

PURPOSE: A method for manufacturing polyvinylacetate using a static mixer is provided to mix polymerizable materials with excellent mixing ratio, to enable the polymerization of solution using a small amount of a solvent, and to manufacture a polymer having high purity and high molecular weight at low reaction pressure and temperature. CONSTITUTION: A method for manufacturing polyvinylacetate using a static mixture comprises the following steps: preparing a polymerization reaction device including a static mixer reactors(1,2,3,4), a material vessel(21) which is connected to the static mixer reactor, and a heater(19) supplying heat of the reaction; preparing a monomer mixture including vinylacetate, a solvent, and an initiator in the material vessel; supplying the monomer mixture to the static mixer reactor; supplying the heat of the reaction to the static mixture reactor from the heater; and polymerizing the monomer mixture by receiving the heat of the reaction from the heater.

Description

Method for producing vinyl acetate polymer using static mixer {METHOD FOR PREPARING POLYVINYLACETATE USING STATIC MIXER}

The present invention relates to a method for producing a vinyl acetate polymer (Polyvinyl acetate), and more particularly to a method for producing a vinyl acetate polymer by polymerizing vinyl acetate (vinyl acetate) by a solution polymerization method using a static mixer as a polymerization reactor. It is about.

Polyvinyl alcohol is a unique polymer that is soluble in water. It was discovered by Herrman and Haehnel of Germany in 1924 and industrialized in Japan in 1948 after World War II and commercialized as a resin for textiles. Polyvinyl alcohol cannot be prepared by direct polymerization of monomers due to tautomerization of vinyl alcohol, and is a hydroxyl-containing linear crystal polymer prepared by saponifying a vinyl ester polymer such as vinyl acetate polymer with acid or alkali. As can be seen in the manufacturing process, it has excellent solvent and oil resistance.

In general preparation of vinyl acetate polymers for use as precursors of poly (vinyl alcohol), bulk polymerization, solution polymerization or suspension polymerization are used.

However, the bulk polymerization has the advantage of obtaining a relatively high molecular weight vinyl acetate polymer because of the low probability of chain transfer because only monomer is present in the polymerization system.However, since the heat of polymerization of vinyl acetate is high, it is difficult to control the viscosity to obtain an actual product. There is a difficult problem [SRsandler and W. Karo, “Polymer Synthesis”, vol. 3, pp. 197-199, Academic Press, New York, 1980].

Solution polymerization is relatively easy to control viscosity and exotherm by solvents in the reaction system, so ethyl acetate [A.Conix and J.Smets, J.Polym, Sci., 10,525 (1953)], acetic acid, dimethylformamide and chloride Solution polymerization of vinyl acetate using various solvents such as ethylene has been studied a lot, but there are problems in that branching reactions and termination reactions frequently occur due to frequent chain transfer reactions, thereby obtaining a high molecular weight vinyl acetate polymer.

In addition, suspension polymerization has a problem that it is disadvantageous to obtain a high-purity transparent vinyl acetate polymer because a lot of dispersants and other additives in water.

The present invention provides a method for preparing a vinyl acetate polymer by solution polymerization using a polymerization reactor equipped with a separate motor stirrer and a heater, which has irregular mixing efficiency, low reaction rate, increase and complexity of the volume associated with the reactor, and gel effect ( It is characterized by using a static mixer as a reactor to solve problems such as unstable reactivity due to gel effect, difficult operation temperature control, generation of unwanted impurities in the shaft and upper small space of the motor-stirred reactor. . By using a static mixer as a reactor, the above problems can be solved by solution polymerization using a small amount of solvent to prepare a high purity, high molecular weight vinyl acetate polymer with high polymerization conversion rate.

The present invention is to solve the above problems, it is an object of the present invention to provide a method for producing a vinyl acetate polymer using a static mixer as a polymerization reactor.

The present invention provides a polymerization reactor comprising (A) a static mixer reactor, a raw material container connected to the static mixer reactor for continuous supply of raw materials, and a heating device installed outside the static mixer reactor for supplying reaction heat as a means for solving the fruit. Preparing a;

(B) preparing a monomer mixture including vinyl acetate, a solvent and an initiator in the raw material container;

(C) supplying the monomer mixture from the raw material container to the static mixer reactor;

(D) supplying reaction heat from the heating apparatus to the static mixer reactor to which the monomer mixture is supplied; And

(E) polymerizing the monomer mixture with the supplied heat of reaction; Disclosed is a method for producing a vinyl acetate polymer using a static mixer comprising a.

In addition, the present invention is a solvent for 0.05 to 1.0 mol (mol) relative to 1 mol (mol) of vinyl acetate as the monomer mixture as a means for solving the above problems; And an initiator 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mole (mol). The method for producing a vinyl acetate polymer using a static mixer is disclosed.

In the method for preparing a vinyl acetate polymer using the static mixer of the present invention, by using the static mixer as a polymerization reactor, the polymerization reactants can be mixed with excellent mixing efficiency, and a solution polymerization using a small amount of solvent is possible. High purity and high molecular weight polymers can be prepared with high polymerization conversion rate at short reaction time under pressure and low reaction temperature, stable polymerization without gel effect can be carried out with simple device and low cost, and easy control of polymerization heat In addition, since there is no interface with the gas phase in the reactor, there is an effect of providing a method for producing a vinyl acetate polymer having a low incidence of polymerization impurities that may stick to the inner wall of the reactor during long time operation.

Method for producing a vinyl acetate polymer using the static mixer of the present invention for achieving the above object

(A) preparing a polymerization reactor comprising a static mixer reactor, a raw material container connected to the static mixer reactor for continuous supply of raw materials, and a heating device installed outside the static mixer reactor to supply reaction heat;

(B) preparing a monomer mixture including vinyl acetate, a solvent and an initiator in the raw material container;

(C) continuously supplying the monomer mixture from the raw material container to the static mixer reactor;

(D) supplying heat of reaction from the heating apparatus to the static mixer reactor supplied with the monomer mixture; And

(E) polymerizing the monomer mixture with the supplied heat of reaction; Characterized in that it comprises a.

Method for producing a vinyl acetate polymer using the static mixer of the present invention, the monomer mixture is a solvent 0.05 to 1.0 mol (mol) per 1 mol (mol) of vinyl acetate; And it is characterized in that the monomer mixture comprising an initiator 1x10 ^-5 to 1x10 ^-3 mol (mol).

In addition, the method for producing a vinyl acetate polymer using the static mixer of the present invention is characterized in that the initiator contained in the monomer mixture is a radical initiator having a half life of 1 to 10 minutes.

The method for producing a vinyl acetate polymer using the static mixer of the present invention is characterized in that the monomer mixture is continuously polymerized while maintaining an average residence time of 5 to 100 minutes at a temperature of 30 to 150? In a static mixer reactor. .

Vinyl acetate polymer using the static mixer of the present invention is characterized in that the number average degree of polymerization of 500 to 20,000.

The polymerization reaction apparatus of the present invention is connected to the static mixer reactors (1, 2, 3), the static mixer reactor as shown in Figure 1 is installed outside the raw material container 16 and the static mixer reactor to continuously supply the raw material reaction heat It may be configured as a heating device 11 for supplying. The heating device 11 is preferably an electric heating device.

See the Journal of Environmental Engineering, S. Casey jones etc., May 2003, 431.

In the present invention, it can be carried out at a polymerization temperature of 30 to 150 ℃ for polymer polymerization for high viscosity, it is preferable to use a Kenics type reactor of the outer diameter 1/2 inch. By using the above static mixer as a reactor, the polymerization reactants can be mixed with excellent mixing efficiency, the solution polymerization using a small amount of solvent is possible, and the polymer is polymerized at a high polymerization rate for a short reaction time at low reaction pressure and low reaction temperature. It can be manufactured, it is possible to carry out stable polymerization reaction without gel effect with simple device and low cost, easy to control polymerization reaction heat, and there is no interface with gas phase in reactor, so it can stick to reactor inner wall during long time operation. It is possible to suppress the generation of possible polymerization impurities.

The static mixer reactor may be used by connecting one or more static mixers in series according to the reaction scale. The static mixer is a mixer designed in the form of a tube in which the flow path of the reaction solution installed therein is disposed at 90 degrees, each unit 180 degrees twisted to the left and right, this type divides the flow of the reaction solution into two, and then re-match To allow mixing by simple flow of fluid without a drive such as a stirrer. One or more unit grids disposed inside the static mixer may be installed in series inside the static mixer, depending on the reaction scale.

In the raw material container of the present invention, a monomer mixture is prepared. The monomer mixture includes a vinyl acetate monomer, an initiator and a solvent.

The initiator contained in the monomer mixture of the present invention is preferably a radical initiator having a half life of 1 to 10 minutes. An initiator having a half-life of less than 1 minute may have an excessively short half-life to use an excessive amount of initiator in order to obtain a desired polymerization conversion rate, which may adversely affect physical properties. When the initiator has a half life of more than 10 minutes, the polymerization time required is long, and productivity is lowered.

The radical initiator is 2,2'-azobis (2,4-dimethylvalenonitrile) (2,2-azobis (2,4-dimethylvaleronitrile), V-65), azobisisobutyronitrile (azobis isobutyronitrile, AIBN), benzoyl peroxide (BPO), dilauuroyl peroxide (LPO), tert-butyl- (2-ethylhexyl) monoperoxycarbonate (t-butyl (2-ethylhexyl) monoperoxycarbonate, TBEC), tert-amyl- (2-ethylhexyl) monoperoxycarbonate (t-amyl- (2-ethylhexyl), TAEC), 1,1-di (tert-butylperoxy) cyclohexane ( 1,1-di (t-butylperoxy) cyclohexane, 1,1-di (tertary-amylperoxy) cyclohexane (1,1-di (t-amylperoxy) cyclohexane), tert-butyl peroxy-3 , 5,5-trimethylhexanoate (t-butyl peroxy-3,5,5-trimethylhexanoate), and 1,1-di (tertiary-butyl peroxy) -3,3,5-trimethylcyclohexane (1 , 1-di (t-butyl peroxy) -3,3,5-trimethylcyclohexane) can be used one or more selected from the group consisting of .

The radical initiator is preferably included in a ratio of 1x10 ^-5 mol (mol) to 1x10 ^-3 mol (mol) with respect to 1 mol (mol) of vinyl acetate, when the content is less than 1x10 ^-5 mol (mol) ratio There is a problem that the polymerization conversion rate is too low, such as about 10%, and when the ratio exceeds 1x10 ^-3 mole (mol) ratio, there is a problem that the product properties due to excess is concerned.

The solvent contained in the monomer mixture of the present invention may use one or more selected from the group consisting of methyl alcohol, ethyl acetate, acetic acid, dimethyl formamide, and ethylene chloride.

The amount of the solvent is preferably contained in a ratio of 0.05 to 1.0 mol (mol) with respect to 1 mol (mol) of vinyl acetate, and less than 0.05 mol (mol) ratio of vinyl acetate polymer of very high viscosity such as bulk polymerization It is difficult to obtain a vinyl acetate polymer having a high molecular weight when it is obtained, and a problem occurs in transport, and when it exceeds 1.0 mole ratio. The molecular weight control of vinyl acetate polymer is related to the reaction temperature and the amount of polymerization initiator, but in the case of the above products, it is inversely proportional to the content of the solvent. Therefore, to control or increase the number average degree of polymerization of the vinyl acetate polymer, a minimum amount of solvent should be used. .

The monomer mixture of the present invention may further include a component such as a molecular weight modifier in a range that does not impair the effects of the invention.

Preferred polymerization conditions of the present invention are the polymerization temperature of 30 to 150 ℃, the average residence time of 5 to 100 minutes and the polymerization pressure in the range of 1 to 10 bar, which is very small molecular weight when the reaction temperature is 150 ℃ or more, 30 ℃ or less In the case of low conversion rate, the residence time has to be very long. The residence time is related to the reaction temperature and depends on the conversion rate and molecular weight. At this time, by adjusting the reaction temperature and residence time, the pressure is determined in proportion to this. If the pressure is artificially lowered without being proportional, the reaction will proceed unreacted.

If the average residence time is less than 5 minutes, the initiator remains in the polymer and there is a problem in the polymerization stability after the completion of the reaction, and if it exceeds 100 minutes, there is a problem that the productivity is lowered.

The polymerization conversion rate of vinyl acetate by the continuous polymerization method using the static mixer reactor as described above is 23 to 72% by weight. Although the conversion rate is 50-70% in solution polymerization in a general reactor and the conversion rate is 50-80% in suspension polymerization, the vinyl acetate polymer obtained in suspension polymerization cannot be used for high purity, high molecular weight, etc. for optical use. It is not a target.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Structure and working principle of the static mixer reactor of the present invention according to the Journal of Environmental Engineering (S.Casey jones etc., May 2003, 431), in the present invention for high viscosity polymer polymerization of 30 to 150 ℃ The polymerization can be carried out at the polymerization temperature, and a Kenics type reactor having an outer diameter of 1/2 inch was used.

Example 1

As shown in FIG. 1, four kneas-type static mixers 1, 2, 3 and 4 made of stainless steel having an outer diameter of 12, 13, 14 and 15 0.5 inch and 64 twisted lattice elements are in series. A polymerization reactor consisting of a static mixer reactor, a raw material container 21, and an electric heating device connected to the reactor was prepared.

90 mol of vinyl acetate monomer (VAM, manufactured by Junsei Chemicals Co., Japan) and 0.0001 mol% of 2,2'-azobis (2,4-dimethylvaleno) relative to the total mol of vinyl acetate monomer Nitrile) (V-65, manufactured by Wako Pure Chemical Ind. Ltd., Japan) and 10 mol% of methyl alcohol (manufactured by Daejung Chemical Co., Ltd., Korea), and the 2,2'-azobis (2,4- The monomer mixture was prepared and prepared by mixing for 30 minutes so that dimethylvalenonitrile) could be completely dissolved.

A 1/8 inch tube connected with nitrogen was inserted into a raw material container prepared with the monomer mixture and blown at a rate of 100 ml / min to maintain the residual air in the monomer mixture at 1.0 ppm or less.

While supplying the monomer mixture from the raw material container to the static mixer reactor at a rate of 8 g / min using a high pressure pump, it is heated by an electric heater installed outside the static mixer, and the polymerization reaction is performed at a temperature of 60 ° C. and a pressure of 1 bar. Proceeded. The linear velocity at this time was 0.1 cm / sec, the residence time per one static mixer was 3.5 minutes, and the total residence time was 14 minutes. 1 hour after the start of the reaction, the internal temperature at the end of the second static mixer was 65 ° C. and the internal temperature at the end of the fourth static mixer was 62 ° C. After measuring the weight average molecular weight (Mw) and the polymerization conversion rate of the vinyl acetate polymer prepared by the polymerization reaction, the results are shown in Table 1 below.

[Examples 2 to 6]

A vinyl acetate polymer was prepared in the same manner as in Example 1 using the polymerization apparatus and polymerization conditions as shown in Table 1 below.

After measuring the weight average molecular weight and polymerization conversion of the vinyl acetate polymer prepared, the results are shown in Table 1 below.

TABLE 1

Example One 2 3 4 5 6 VAM (mol) 90 90 90 90 90 90 Initiator (mol%) 90x1x10 ^-4 90 x 10 ^-2 90 x 10 ^-5 90 x 10 ^-4 90 x 10 ^-4 90 x 10 ^-4 Solvent (mol%)  10 10 10 4.5 45 90 Polymerization temperature 60 ℃ 60 ℃ 40 ℃ 60 ℃ 100 ℃ 100 ℃ Flow rate (g / min) 8 8 8 1.2 1.2 1.2 Pressure (bar) One One One 2 2 2 Retention time (minutes) 14 14 14 90 90 90 % Conversion 42.3 65.4 51.7 66.2 73.1 73.1 Weight average molecular weight 263,000 863,000 1,450,000 1,230,000 87,000 87,000

As shown in Table 1, using a static mixer reactor according to the present invention, Example 1 to produce a vinyl acetate polymer while changing the polymerization conditions of the type and amount of the initiator, polymerization temperature, flow rate, pressure, residence time It can be seen that 6 represents a polymerization conversion rate of 42 to 73% for a short residence time of 14 to 90 minutes at a polymerization temperature of 40 to 100 ° C. and a polymerization pressure of 1 to 2 bar.

Specifically, in Example 1, vinyl acetate polymer was prepared at a polymerization conversion rate of 42% even during a short residence time of 14 minutes even at a low polymerization temperature of 60 ° C. Example 2 produced a vinyl acetate polymer with a polymerization conversion of 65% for a short residence time of 14 minutes even at a low polymerization pressure of 1 bar. In Example 6, a vinyl acetate polymer was prepared with a high polymerization conversion rate of 73% at a polymerization temperature of 100 ° C. and a polymerization pressure of 2 bar at a residence time of 90 minutes, so that under the same conditions, the higher the polymerization pressure, the lower the flow rate, It was found that the longer the residence time, the higher the polymerization conversion rate was, and a high purity vinyl acetate polymer having a weight average molecular weight of 90000 to 1400000 was obtained.

In addition, when the static mixer according to the present invention was used, a sudden exothermic reaction did not occur during the polymerization reaction, and thus stable polymerization could be performed, and thus, it was found that delicate temperature control was not necessary. In addition, polymerization impurities adhering to the reactor inner wall could not be observed.

1 is a view showing a polymerization apparatus for performing a polymerization reaction according to the present invention.

Brief description of the main symbols in the drawings

1, 2, 3, 4: static mixer

5: total length of static mixer reactor

6, 7, 8, 9: length of one static mixer

10, 11: Tube Fitting

12, 13, 14, 15: outer diameter of one static mixer

16: External temperature measuring instrument

17, 18: internal temperature meter

19: electric heating wire and thermostat

20: high pressure pump

21: Raw material container

22: nitrogen source

Claims (11)

(A) preparing a polymerization reactor comprising a static mixer reactor, a raw material container connected to the static mixer reactor for supplying raw materials, and a heating device installed outside the static mixer reactor to supply reaction heat; (B) preparing a monomer mixture including vinyl acetate, a solvent and an initiator in the raw material container; (C) supplying the monomer mixture from the raw material container to the static mixer reactor; (D) supplying reaction heat from the heating apparatus to the static mixer reactor to which the monomer mixture is supplied; And  (E) receiving the reaction heat from the heating device to polymerize the monomer mixture; characterized in that it comprises a method of producing a vinyl acetate polymer using a static mixer. The method of claim 1, The static mixer reactor is a method for producing a vinyl acetate polymer using a static mixer, characterized in that one or more connected in series. The method of claim 1, The monomer mixture is a solvent 0.05 to 1.0 mol (mol) with respect to 1 mol (mol) of vinyl acetate; And a monomer mixture comprising an initiator in an amount of 1 × 10 ⁻⁵ to 1 × 10 ⁻³ mole (mol). The method of claim 1, The initiator contained in the monomer mixture is a radical initiator having a half-life of 1 to 10 minutes, characterized in that the method for producing a vinyl acetate polymer using a static mixer. The method of claim 1, The radical initiator contained in the monomer mixture is 2,2'-azobis (2,4-dimethylvalenonitrile), azobisisobutyronitrile, benzoyl peroxide, dilauroyl peroxide, tertiary-butyl- (2-ethylhexyl) monoperoxycarbonate, tertiary-amyl- (2-ethylhexyl) monoperoxycarbonate, 1,1-di (tertiary-butylperoxy) cyclohexane, 1,1-di (ter Sherry-amylperoxy) cyclohexane, tert-butyl peroxy-3,5,5-trimethylhexanoate, and 1,1-di (tertiary-butyl peroxy) -3,3,5-trimethylcyclo A method for producing a vinyl acetate polymer using a static mixer, characterized in that one or two or more selected from the group consisting of hexane. The method of claim 1, The solvent contained in the monomer mixture is methyl alcohol, ethyl acetate, acetic acid, dimethyl formamide and ethylene chloride. The method for producing a vinyl acetate polymer using a static mixer, characterized in that at least one selected from the group consisting of. The method of claim 1, Polymerization method using a static mixer, characterized in that the polymerization temperature for supplying the reaction heat from the heating device to polymerize the monomer mixture is 30 to 150 ℃. The method of claim 1, The monomer mixture is a method of producing a vinyl acetate polymer using a static mixer, characterized in that the average residence time of the static mixer reactor is 5 to 100 minutes. The method of claim 1, The polymerization reaction pressure of the static mixer reactor is a method for producing a vinyl acetate polymer using a static mixer, characterized in that 1 to 10 bar. The vinyl acetate polymer produced by the manufacturing method of the vinyl acetate polymer using the static mixer in any one of Claims 1-9. The method of claim 10, The vinyl acetate polymer is a vinyl acetate polymer, characterized in that the weight average molecular weight of 90000 to 1400000.

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