KR101529750B1 - Metal deactivator composition for manufacture of vinyl chloride resin and method of preparing vinyl chloride resin using the same - Google Patents

Abstract

The present invention relates to a metal deactivator composition for the production of a vinyl chloride resin having an acidic metal deactivator and an alkali metal deactivator and having a pH in the range of 6.0 to 8.0 in aqueous solution, A method of effectively deactivating the side reactions between the transition metal and the vinyl chloride monomer is proposed to prevent the generation of scales occurring in the polymerization reactor and to prevent non-uniform dispersion of the polyvinyl alcohol-based dispersant, A method of improving the generation of migrating particles during processing is provided by manufacturing a resin having a high thermal conductivity and an improvement in appearance properties of the final product as well as an improvement in mechanical properties by preventing deterioration of the thermal stability of the resin of the transition metals It has a possible advantage.

Description

TECHNICAL FIELD The present invention relates to a metal deactivator composition for preparing a vinyl chloride resin and a method for producing the vinyl chloride resin using the same,

The present invention relates to a metal deactivator composition for the production of a vinyl chloride resin and a process for producing a vinyl chloride resin using the same. More specifically, the present invention relates to a process for producing a vinyl chloride resin by reducing the thermal stability While preventing non-uniform distribution of particle size and uneven distribution of internal voids caused by scale generation of the reactor and non-uniform dispersion of the polyvinyl alcohol-based dispersant and preventing generation of migrating ring particles during processing, The present invention relates to a metal deactivator composition for preparing a vinyl chloride resin using the same and a method for producing a vinyl chloride resin using the same.

The vinyl chloride monomers used in the production of vinyl chloride resins are produced through two routes: one is a process of hydrochlorination using acetylene as a raw material, and the other is a process in which ethylene is reacted with oxo (EDC) is produced by oxochlorination or chlorination, followed by pyrolysis to obtain hydrogen chloride and vinyl chloride monomer. In the process for producing vinyl chloride monomer from ethylene, a technique of utilizing a catalyst as a method for increasing the yield of a product has been developed from the past. As described in U.S. Patent No. 4,115,323 and U.S. Patent No. 6,909,024, Have been used as catalysts. Currently, the most widely used catalysts are those of rhodium (Rh), platinum (Pt), iron (Fe), copper (Cu), nickel (Ni) .

Although these catalysts theoretically function as catalysts, it is normal that they are not consumed during the reaction, but since the production process proceeds under high acidity conditions, these metals are introduced into the polymerization process of the resin together with the vinyl chloride monomer in the form of chloride . Among them, the transition metal compounds such as iron and copper are introduced into the vinyl chloride resin, and when they are subjected to the final processing, the performance of the metal stabilizer introduced during the processing is seriously impaired, and the whiteness of the product and the weather resistance are deteriorated.

In addition to the transition metals introduced from the catalyst, the monomers not consumed during the polymerization of the vinyl chloride resin are recovered and recycled during the next polymerization. In the reactor and piping, in addition to the metal chloride, III) is generated.

Particularly, the corrosion of the reactor proceeds, and the produced metal chloride accelerates the radical decomposition of the peroxygen compound used in the polymerization of the vinyl chloride resin, thereby accelerating scale formation at the point where corrosion occurs. Since the scale generated at this time grows in a state in which almost no stirring occurs, the bead-shaped particle structure having no voids therein is formed.

When these particles are introduced into the resin, they are not properly blended with heat stabilizers and plasticizers during processing and are not melted at the processing temperature, resulting in migrating particles exhibiting low whiteness.

In addition, the presence of the transition metal causes aggregation of the polyvinyl alcohol-based dispersant to cause a drop in dispersion. As a result, an uneven particle size distribution is formed, or the dispersing agent concentrates only on specific particles, Do not let them. These particles appear as migrating ring particles during processing.

Miglyring particles not only hinder the transparency of the product but also act as a starting point of the fracture behavior in the case of external impact or stress, deteriorating the mechanical properties of the whole product.

Conventional techniques for solving such problems are disclosed in US Pat. Nos. 3,669,946, 40-30,835, and 45-30,343, which disclose a method in which a dye or a polar organic compound is added to the surface of a reactor and a stirrer baffle And a method of spraying and crosslinking a condensation reaction product of naphthol and formaldehyde on the surface of a reactor as shown in U.S. Patent Nos. 4,404,357 and 6,069,199, and attaching the resultant to the surface.

However, there is a limitation in that the corrosion prevention film coating method can not prevent the influence of the influx of the metal chloride introduced from the above-mentioned catalyst or the metal chloride generated by the corrosion of the apparatus.

Therefore, a technique of spraying and drying the metal deactivator prior to the coating of the descaler using a separate spraying device, such as U.S. Patent No. 6,355,743, has been developed.

However, such a technique must be uniformly sprayed on the surface of the reactor using nozzles in the absence of reactants, and must be coated with steam to form a film on the surface. However, it is difficult to suppress scale generation in a portion where injection is not easily performed, such as the back surface of an agitator or a baffle, and it takes time to spray and dry the anti-scale material, resulting in a decrease in productivity.

In addition, when the metal deactivator added at the initial stage of the reaction exhibits alkalinity, there arises a problem that the amount of the dispersing agent must be increased in order to increase the particle size by decreasing the efficiency of the dispersing agent and accordingly to produce the resin having the desired particle size.

Due to this problem, the problem has been solved by injecting the metal deactivator after the generation of particles has been made to some extent. However, this method is not only difficult to inhibit the initial scale formation of the reaction, but also requires additional equipment such as a high-pressure pump for input during the reaction, and solves the problems caused by the dispersibility of the dispersant due to the presence of transition metals There is a limit.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art as described above, and it is an object of the present invention to provide a resin having uniform particle size distribution and internal voids by preventing uneven dispersion of a polyvinyl alcohol- In order to provide a method for improving the performance of the system.

It is still another object of the present invention to provide an improvement in mechanical properties as well as an improvement in appearance characteristics such as a fish-eye of a final product by preventing deterioration of the thermal stability of the resin by transition metals.

These and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a metal deactivator composition for producing a vinyl chloride resin, which comprises an acidic metal deactivator and an alkali metal deactivator and has a pH of 6.0 to 8.0 in an aqueous solution.

The present invention also provides a process for producing a vinyl chloride resin, which comprises adding a metal deactivator composition for producing a vinyl chloride resin as described above to a vinyl chloride resin to produce the vinyl chloride resin.

INDUSTRIAL APPLICABILITY As described above, the present invention can improve the transparency, mechanical properties, and the like lowered by migrating ring particles during processing, and prevent the deterioration of the productivity required for removing scale in the production process of vinyl chloride resin It is possible to improve the thermal stability of the final product.

According to the method of the present invention described above, in the step of producing a vinyl chloride resin, a substance having a stabilizing action against transition metals is selected by selecting at least one of alkaline and acidic materials, and using a specific ratio and a predetermined amount It is possible to prevent the formation of scales occurring in the polymerization reactor and to produce a resin having a uniform particle size distribution and an internal void, thereby improving the generation of migrating particles during processing of the resin, It is possible to improve the appearance characteristics such as the fish-eye of the final product as well as to improve the mechanical properties.

The present invention provides a method for selecting and injecting a metal deactivator which is injected into a polymerization reactor from the beginning of reaction to effectively remove the transition metals.

The present invention provides a metal deactivator composition for producing a vinyl chloride resin having an acidic metal deactivator and an alkali metal deactivator and having a pH in the range of 6.0 to 8.0 in an aqueous solution.

According to the present invention, there is provided a method for preventing scale formation of a reactor and promoting dispersion of a dispersant by inactivating a catalytic function of a transition metal,

1) one or more acidic metal deactivators having a pH of 7 or less in an aqueous solution and

2) At least one of the alkali metal deactivators having a pH of 7 or higher in an aqueous solution state is selected,

3) the composition was determined to have a pH of 6.0 to 8.0 in the aqueous solution state,

4) in the range of 5 to 500 ppm

5) By using at any time during polymerization and polymerization,

It is possible to manufacture a resin having excellent thermal stability by inhibiting the occurrence of corrosion and scale of the apparatus and dispersibility of the dispersant to prevent deterioration of appearance and mechanical properties due to Miglyring particles.

In other words, the present invention relates to a metal deactivator composition for producing a vinyl chloride resin having an acidic metal deactivator and an alkali metal deactivator and having a pH in the range of 6.0 to 8.0 in an aqueous solution, and a process for producing a vinyl chloride resin The present invention also provides a method for producing a vinyl chloride resin by adding a metal deactivator composition for producing a vinyl chloride resin as described above to produce a vinyl chloride resin. The production method of the vinyl chloride resin is preferably a suspension polymerization.

The acidic metal deactivators described in 1) above

(a) a compound represented by the following general formula (1), and examples thereof include pyrophosphoric acid, tripolyphosphoric acid, pentapolyphosphoric acid, trimetaphosphoric acid, acid, tetrametaphosphoric acid, or hexametaphosphoric acid.

[Chemical Formula 1]

HO (HPO ₃ ) _n H

In the above formula, n is an integer of 2 or more.

b) an aminocarboxylic acid-based substance, typically ethylenediamine-N-monoacetic acid, ethylenediamine-N, N'-diacetic acid and ethylenediamine-N, N, N ', N'-tetraacetic acid .

c) an oxycarboxylic acid-based substance, typically a substance having a carboxyl group and a hydroxyl group in a molecular structure, such as a glycolic acid, a gluconic acid, a lactic acid, a glyceric acid, Glyceric acid, tartaric acid, malic acid, salicylic acid, gallic acid, or citric acid.

The alkali metal deactivator described in 2) above can be used regardless of the kinds of the substances d) and e) below.

d) A material having the structure of the alkali metal salt of the phosphatic acid-based material described in a) above and having the structure of the alkali metal salt of the phosphatic acidic alkali metal salt represented by the following formula (2). Typically, sodium pyrophosphate pyrophosphate, potassium pyrophosphate, trisodium trimetaphosphorate or tetrasodium tetrametaphosphate. The term " pyrophosphate "

(2)

X _n O (HPO ₃ ) _n

In the above formula, n is an integer of 2 or more, and X is an alkali metal.

e) Materials made in the form of the aminocarboxylic acid-based alkali metal salts described in b) above, and typically include sodium-ethylenediamine-N-monoacetic acid, disodium-ethylenediamine-N, N'- diacetic acid, Sodium-ethylenediamine-N, N, N ', N'-tetraacetic acid, and the like.

3) The metal deactivator mixture is prepared by selecting at least one of the materials from 1) and 2) above and determining the composition to give a hydrogen ion concentration (pH) of between 6.0 and 8.0 in the aqueous solution. The general composition is that the ratio of the acidic metal deactivator to the alkali metal deactivator is in the range of 3 to 10. If the pH of the prepared metal deactivator mixture is less than 6.0, the corrosion of the reactor or the decomposition reaction of the vinyl chloride resin due to the increase in acidity is accelerated to deteriorate the thermal stability. If the pH is more than 8.0, And the amount of the dispersant used must be increased accordingly.

4) The amount of the metal deactivator composition used for producing the vinyl chloride resin is preferably 5 to 500 ppm, and when it is less than 5 ppm, it is difficult to show the desired improvement, and when it exceeds 500 ppm, the cost increases and the problem caused by the increase in the conductivity of the polymer Lt; / RTI >

5) If the composition and the amount of metal deactivator are determined by the above method, they can be used at any point in the initial stage of the reaction at any stage of the reaction. In order to obtain the desired improvement effect, It is more preferable to use it.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Production Example 1

15 g of sodium pyrophosphate as an alkali metal deactivator and 1 g of a cytic acid as an acidic metal deactivator were stirred in 2 kg of distilled water at room temperature for 1 hour to prepare a mixed solution of pH 7.7.

Production Example 2

31 g of sodium pyrophosphate as an alkali metal deactivating agent and 6 g of an acidic metal deactivator as a acidic metal deactivator were stirred in 2 kg of distilled water at room temperature for 1 hour to prepare a mixed solution of pH 6.5.

Production Example 3

To 15 g of tetrasodium-ethylenediamine-N, N ', N'-tetraacetic acid as an alkali metal inactivating agent, 2 g of pyrophosphoric acid as an acidic metal deactivator was stirred in 1 kg of distilled water at room temperature for 1 hour a mixed solution of pH 7.2 was prepared.

Comparative Example 1 (Suspension polymerization)

As a general suspension polymerization method, a dispersant having a degree of hydration of 88%, a dispersant having a degree of hydration of 72%, a dispersant having a degree of hydration of 55%, and a hydroxypropyl methylcellulose dispersant in a protective colloid solution were mixed at a ratio of 3: 6: 2: 1 0.06 part by weight of the monomer was added, and 0.04 part by weight of t-butyl peroxyneodecanoate as an initiator was added to the monomer. Thereafter, the inner pressure of the reactor was degassed in a high vacuum of less than 70 torr to remove oxygen and other impurities. 100 parts by weight of a vinyl chloride monomer was added thereto. These fractions were stirred at a speed of 180 times and reacted at a temperature of 58 캜 for 4 hours.

Then, the remaining unreacted monomers were removed while lowering the temperature, and a slurry was obtained and dried in a conventional manner to obtain a final resin.

Comparative Example 2 (suspension polymerization method + alkali metal deactivator at the initial stage of the reaction)

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 15 g (50 ppm) of sodium pyrophosphate was added as an alkali metal inactivating agent into the reactor at the initial stage of polymerization in Comparative Example 1, and then added.

Comparative Example 3 (suspension polymerization method + reaction medium alkaline metal deactivator)

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 15 g (50 ppm) of sodium pyrophosphate was dissolved in 1 L of water as an alkali metal deactivator into the reactor after 90 minutes from the start of the polymerization in Comparative Example 1 Respectively.

Comparative Example 4 (Suspension polymerization + initial acidic metal deactivator)

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 6 g (20 ppm) of the acidic acid as an acidic metal deactivator was added into the reaction vessel at the initial stage of polymerization in Comparative Example 1, and the mixture was added.

Comparative Example 5 (suspension polymerization method + reaction medium acid metal deactivator)

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 6 g (20 ppm) of the acidic acid as an acidic metal deactivator was dissolved in 1 L of water into the reactor after 90 minutes from the start of the polymerization in Comparative Example 1, Respectively.

Example 1 (suspension polymerization + initial pH 7.7 metal deactivator mixture)

Polymerization was carried out under the same conditions as in Comparative Example 1 except that 53 ppm of the metal deactivator mixed solution of pH 7.7 prepared in Preparation Example 1 was added into the reactor at the beginning of polymerization in Comparative Example 1.

Example 2 (Suspension polymerization + middle reaction pH 7.7 metal deactivator mixture)

Polymerization was conducted and evaluated in the same manner as in Comparative Example 1 except that 53 ppm of the metal deactivator mixed solution of pH 7.7 prepared in Production Example 1 was fed into the reactor 90 minutes after the start of the polymerization in Comparative Example 1.

Example 3 (suspension polymerization method + mid-reaction pH 6.5 metal deactivator mixture)

Polymerization was conducted and evaluated in the same manner as in Comparative Example 1, except that 12 ppm of the metal deactivator mixed solution prepared in Production Example 2 at pH 6.5 was added into the reactor at the beginning of polymerization in Comparative Example 1.

Example 4 (suspension polymerization method + initial pH 6.5 metal deactivator mixture)

Polymerization was conducted and evaluated in the same manner as in Comparative Example 1, except that 12 ppm of the metal deactivator mixed solution prepared in Production Example 2 at pH 6.5 was added into the reactor at the beginning of polymerization in Comparative Example 1.

Example 5 (Suspension polymerization + initial pH 7.2 metal deactivator mixture)

Polymerization was conducted and evaluated in the same manner as in Comparative Example 1, except that 12 ppm of the metal deactivator mixed solution prepared in Production Example 3 at pH 7.2 was added into the reactor at the beginning of polymerization.

[Test Example]

The physical properties of the resins prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were measured by the following methods, and the results are shown in Table 1 below.

* Scale Emission Impact Strength: After the polymerization reaction was completed, all of the slurry was discharged outside the reactor, and then the scales remaining on the wall surface and the impeller were collected, and the amount of the generated amount was expressed in terms of mass.

Measurement of thermal stability: To 100 parts by weight of the vinyl chloride resin obtained in the above Examples and Comparative Examples, 3 parts by weight of a lead-based stabilizer, 0.3 parts by weight of barium stearate and 0.1 part by weight of titanium dioxide were added and mixed by using a roll mill And kneaded at 185 DEG C for 5 minutes to obtain a sheet having a thickness of 0.5 mm.

Then, the whiteness (W.I) value was measured using NR-3000 manufactured by Nippon Denshoku Co., Ltd. The results are shown. The thermal stability can be measured from the whiteness value. The higher the value, the better the thermal stability.

* Measurement of particle diameter and particle size distribution: The obtained resin was measured for particle size using a HELOS particle size analyzer of Sympatec Co., and the span value at that time was defined as a particle size distribution. The lower the span value, the smaller the deviation.

Measurement of Miglyring Particles: 45 parts by weight of dioctyl phthalate, 2 parts by weight of lead-based stabilizer, 1 part by weight of barium stearate internal lubricant and 0.3 g of black pigment were added as a plasticizer to 100 parts by weight of the obtained resin at 155 캜 for 4 minutes After kneading, a sheet having a thickness of 0.4 mm was obtained. The number of white migrating rings existing in an area of 100 cm ^{2 in the} whole sheet was counted.

* Measurement of elongation: The sheet produced during the measurement of the miguel ring particles was cut with a standard tensile test strip and the stretched ratio (elongation) was measured. The higher the value, the better the mechanical properties.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Example 4 Example 5 Input Alkaline system Alkaline system Acid system Acid system pH 7.7 mixture pH 7.7 mixture pH 6.5 mixture pH 6.5 mixture pH 7.2 mixture Time of injection - Early 90 minutes Early 90 minutes Early 90 minutes Early 90 minutes Early Particle size (탆) 124 193 125 115 123 127 125 123 125 128 Particle size distribution
(span) 0.91 0.77 0.89 0.94 0.90 0.70 0.90 0.74 0.91 0.71 Miguel ring particle
(Fish-eye) 24 180 10 35 20 2 9 5 11 8 Thermal stability
(Whiteness degree) 57 59 55 55 59 74 71 72 59 73 Mechanical properties
(Elongation%) 215 170 230 204 220 235 241 245 237 242 scale
(kg) 2.5 1.2 2.1 2.5 2.4 0.3 1.2 0.7 1.5 0.8

As can be seen from the results of the comparative examples and the examples in Table 1, when the alkali metal deactivating agent is initially added, the particle size is increased and the generation of the migrating ring particles is thereby increased to cause deterioration of the physical properties. , The particle size decreases at the initial injection, but the thermal stability is lowered and the scale generation amount due to the increase of the reactor acidity is increased. When these are added in the middle of the reaction, the effect on the morphology of the particles is negligible, but the effect of improving the original scale and improving the migrating particles is small. On the other hand, mixing and maintaining the appropriate pH range of 6.0 to 8.0 as in the examples improves the particle size distribution without changing the particle size, and also improves the occurrence of miguel ring particles, generation of scale, and improvement of both mechanical properties and thermal stability Can be obtained.

Claims (10)

An acidic metal deactivator and an alkaline metal deactivator and has a pH ranging from 6.5 to 8.0 in aqueous solution,
Wherein the acidic metal deactivator is a compound represented by the following formula (1), an aminocarboxylic acid or an oxycarboxylic acid,
Wherein the alkali metal inactivating agent is a phosphatic acidic alkali metal salt represented by the following general formula (2).
[Chemical Formula 1]
HO (HPO ₃ ) _n H
(Wherein n is an integer of 2 or more)
(2)
X _n O (HPO ₃ ) _n
(Wherein n is an integer of 2 or more and X is an alkali metal) delete The method according to claim 1,
The compound represented by Formula 1 is selected from the group consisting of pyrophosphoric acid, tripolyphosphoric acid, penta polyphosphoric acid, trimetaphosphoric acid, tetrametaphosphoric acid and hexametaphosphoric acid. Wherein the metal deactivator composition is a polyvinyl chloride resin. The method according to claim 1,
Wherein the aminocarboxylic acid is selected from the group consisting of ethylenediamine-N-monoacetic acid, ethylenediamine-N, N'-diacetic acid and ethylenediamine-N, N, N'N'-tetraacetic acid Based on the total weight of the metal deactivator composition. The method according to claim 1,
Wherein said oxycarboxylic acid is selected from the group consisting of glycolic acid, gluconic acid, lactic acid, glyceric acid, tartaric acid, malic acid, salicylic acid, gallic acid, and acidic acid. Metal deactivator composition. delete The method according to claim 1,
Wherein the phosphatic acidic alkali metal salt is selected from the group consisting of sodium pyrophosphate, potassium pyrophosphate, trisodium trimaplyphosphate and tetrasodium tetrametaphosphate. . delete A process for producing a vinyl chloride resin, wherein the vinyl chloride resin is produced by adding the metal deactivator composition for producing a vinyl chloride resin according to claim 1, 10. The method of claim 9,
Wherein the amount of the metal deactivator composition for producing a vinyl chloride resin is 5 to 500 ppm.