KR101506063B1 - A method for preparing polyvinyl chloride resin having increased productivity - Google Patents

Abstract

The present invention relates to a method for producing a vinyl chloride resin having improved productivity, and more specifically, to a method for producing a vinyl chloride resin by adding a reducing agent capable of activating an initiator without a metal ion in a timely manner in a suspension polymerization method for producing a vinyl chloride polymer. It is possible to manufacture a vinyl chloride resin with improved productivity which does not deteriorate color because metal ion is not used as well as the conversion rate is improved by inducing rapid consumption.

Description

Technical Field [0001] The present invention relates to a method for preparing a polyvinyl chloride resin having improved productivity,

The present invention relates to a method for producing a vinyl chloride resin having improved productivity, and more specifically, to a method for producing a vinyl chloride resin by adding a reducing agent capable of activating an initiator without a metal ion in a timely manner in a suspension polymerization method for producing a vinyl chloride polymer. The present invention relates to a method for producing a vinyl chloride resin improved in productivity, which does not deteriorate a color because metal ions are not used, as well as a conversion rate is improved by inducing rapid consumption.

Vinyl chloride resin is a plastic with vinyl chloride as its main component. It was born in Germany in 1931 and used for various products that enrich human life for more than 70 years.

Since vinyl chloride resin is excellent in mechanical strength, weather resistance, and chemical resistance, it is a universal resin widely used for living and industrial materials such as film, sheet, and molded article in the world. Since the vinyl chloride resin contains chlorine in the molecule, 60% of the composition is an industrial salt and is called an energy-saving plastic which can save oil resources.

Further, by adding various additives to the vinyl chloride resin, properties such as firmness and durability can be changed according to the purpose. Because of this feature, vinyl chloride resin is used in various applications such as raincoat, shoes, pipe, wire cloth, wallpaper, flooring, window frame, automobile, and household appliance parts.

However, the production cost of the vinyl chloride polymer is required to be reduced due to the continuous increase in the oil price. Therefore, a lot of efforts are being made to improve polymerization productivity.

As a method for improving the polymerization productivity, there is a method in which the polymerization reaction time is constant and the polymerization conversion rate is increased to increase the amount of the polymerization product per batch or to shorten the polymerization reaction time to produce a large amount of the reaction product per unit time.

A method of increasing the polymerization conversion rate of the polyvinyl chloride polymer has been proposed. However, since the polymerization conversion rate is 70% or more when the internal pressure of the polymerization reactor is lowered, The initiator added to the vinyl chloride monomer does not sufficiently react with the vinyl chloride monomer, resulting in an increase in fluorescence or an increase in fine particles, thereby deteriorating the initial coloring property.

In addition, considering that the general conversion rate considering the quality of the vinyl chloride polymer is 85 to 87%, the method of increasing the polymerization conversion rate is not effective in improving the polymerization productivity.

Therefore, in order to improve the productivity of the vinyl chloride resin, efforts have been made in order to shorten the polymerization reaction time. In addition, there is a demand for a stable production method such as polymerization degree of vinyl chloride polymer, .

However, conventionally known vinyl chloride-based polymer production methods have a problem of insufficient polymerization productivity, but insufficient for securing stable quality.

In addition, an oxidation-reduction system is used to increase the activity of the initiator, but the vinyl chloride polymer has a problem that the color is lowered by metal ions.

Considering that vinyl chloride monomer is produced by radical polymerization when an initiator having a half-life is added to the middle of the reaction by the method of shortening the polymerization reaction time of the vinyl chloride polymer, And the growth gradually weakens toward the latter half of the polymerization. Therefore, this method also causes a problem that the initial coloring property is deteriorated due to an increase in the amount of fine particles or an increase in fine particles.

Accordingly, the inventors of the present invention have been studying to overcome the problems of the prior art. In the suspension polymerizing method for producing a vinyl chloride polymer, the inventors of the present invention have found that rapid consumption of a vinyl chloride monomer by injecting a reducing agent capable of activating an initiator, To thereby improve the conversion efficiency and to improve the productivity of the vinyl chloride resin without the use of metal ions. Thus, the present invention has been accomplished.

That is, an object of the present invention is to provide a method for safely and efficiently producing a vinyl chloride polymer having the same physical properties as existing products, while improving polymerization conversion and polymerization productivity in a suspension polymerization method for producing a vinyl chloride polymer.

In order to achieve the above object, the present invention relates to a method for producing a vinyl chloride polymer by suspension polymerization of a vinyl chloride monomer in the presence of a polymerization dispersant and a polymerization initiator, wherein the vinyl chloride polymer is polymerized at a polymerization conversion rate of 20 to 25% And a second polymerization initiator and sodium formaldehyde sulfoxylate as a reducing agent are further added to the reaction system.

Hereinafter, the present invention will be described in detail.

The present invention relates to a process for the production of vinyl chloride polymers which is more productive by incorporating sodium formaldehyde sulfoxylate as a reducing agent capable of activating the initiator without timely metal ions in a suspension polymerization process for preparing vinyl chloride polymer It is a technical feature that it induces fast consumption of a vinyl chloride monomer to improve a conversion ratio and does not use a metal ion and thus does not lower the color.

Hereinafter, the components used in the present invention will be described.

Preferably, the protective colloid is one or more of a vinyl alcohol-based resin, a cellulose or an unsaturated organic acid polymer, or a mixture of two or more thereof.

The vinyl alcohol-based resin preferably has a hydration degree of 30 to 90% by weight, and a viscosity of the 4% aqueous solution of the vinyl alcohol-based resin at 15 to 25 ° C is preferably 10 to 60 cps.

Preferably, the cellulose has a propylhydroxyl group content of 3 to 20% by weight, and the viscosity of the 2% aqueous solution of the cellulose at 15 to 25 ° C is 10 to 20,000 cps.

The polymerization initiator and the additional initiator may be one kind or a mixture of two or more of diacyl peroxide type polymerization initiator, peroxydicarbon type polymerization initiator, peroxy ester type polymerization initiator, and sulfate type polymerization initiator.

The diacyl peroxide-based polymerization initiator may be one of dicumylperoxide, dipentylperoxide, di-3,5,5-trimethylhexanoylperoxide or dilaurylperoxide, or a mixture of two or more thereof.

The peroxydicarbonate polymerization initiator may be one of diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate or di-ethyl hexyl peroxydicarbonate, or a mixture of two or more thereof.

The peroxy ester polymerization initiator may be one of t-butyl peroxypivalate or t-butyl peroxy neodecanoate, or a mixture of two or more thereof.

The sulfate-based polymerization initiator may be one or a mixture of potassium persulfate or ammonium persulfate.

It is preferable that the protective colloid preparation is 0.05 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer to be added before the initiation of the polymerization, and the amount of the polymerization initiator is preferably 0.02 to 0.2 parts by weight based on 100 parts by weight of the vinyl chloride monomer Do.

As the reducing agent, SFT (sodium formaldehyde sulfoxylate) is added in an amount of 50-150 parts by weight, preferably 100 parts by weight, per 100 parts by weight of the initiator.

The polymerization temperature of the vinyl chloride polymer is 30 to 80 캜, the polymerization time is 2 to 6 hours, and the polymerization angular force is 3 to 15 kg / cm 2.

Hereinafter, the production method according to the present invention will be described in detail.

Suspension polymerization in the presence of a protective colloid assistant and polymerization initiator to produce a vinyl chloride resin. When the conversion is 20-25%, 5 to 20% of the vinyl chloride monomer is further added, and 5 To 30% of an initiator as a reducing agent, such as SFS (sodium formaldehyde sulfoxylate), in order to improve the productivity and at the same time to provide a method for producing a polymer equivalent to that of a conventional product. At this time, it is most preferable that the metal ion is not added and the amount of the reducing agent is the same as the amount of the initiator added.

After the impurities such as oxygen are removed from the reactor, the solvent, the initiator, and the protective colloid are added all at once, the vinyl chloride monomer is added, and the reaction is carried out while raising and maintaining the predetermined reaction temperature. At this time, it is preferable that stirring at an appropriate speed is carried out so that the droplet is maintained in a properly suspended state.

After the unreacted residual vinyl chloride monomer is recovered, the resin in the reactor is separated, dehydrated and dried to prepare a vinyl chloride-based copolymer resin.

According to one embodiment of the present invention, in the method of producing a vinyl chloride resin by suspension polymerization of a vinyl chloride monomer in the presence of a polymerization initiator, when the conversion is 20 to 25%, 5 to 20% of a vinyl chloride monomer is further added , sodium fluoride (SFS) as a reducing agent, and 5 to 30% of the initial initiator charge, in the absence of a metal ion such as a ferrous ion or a cuprous ion.

On the other hand, when the above-mentioned vinyl chloride monomer is added at a polymerization conversion rate of less than 10%, the amount of the vinyl chloride monomer to be added can be limited to a small amount, And when the polymerization conversion rate exceeds 40%, it is difficult to control the physical properties of the final vinyl chloride polymer, making it difficult to produce a high quality vinyl chloride polymer. Therefore, the additional conversion time of the vinyl chloride monomer is preferably 10 to 40% , Or in the range of 20 to 25%.

In this method, the reducing agent SFS promotes the decomposition of the initiator to increase the polymerization rate, thereby improving the conversion efficiency, thereby improving the productivity.

In addition, in the above production method, it is preferable that the content of the protective colloid assistant as the polymerization dispersant is 0.05 to 5 parts by weight relative to 100 parts by weight of the vinyl chloride monomer to be added before the initiation of polymerization. When the amount is less than 0.05 part by weight, coarse particles are formed and fish-eye is generated. When the amount is more than 5 parts by weight, there is a problem of initial coloring due to increase of fine particles.

In the present invention, the content of the initiator introduced at the beginning of the polymerization is preferably 0.02 to 0.2 part by weight based on 100 parts by weight of the vinyl chloride monomer to be added before the initiation of polymerization. When the amount of the initiator is less than 0.02 parts by weight, the reaction time is delayed to lower the conversion and productivity. When the amount exceeds 0.2 parts by weight, the initiator is not completely consumed during polymerization and the final resin product remains, there is a problem.

The content of the second polymerization initiator to be added is preferably 0.02 to 0.25 parts by weight based on 100 parts by weight of the additional amount of the vinyl chloride monomer. If the amount is less than 0.02 parts by weight, the effect of improving the conversion is small. If the amount is more than 0.25 part by weight, heat release is difficult due to the limit of the amount of heat and the initiator is not completely consumed.

In addition, it is preferable to add the reducing agent SFS in a batch or continuous manner in the above-described production method in an amount of 50 to 150 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the added initiator, If the amount is less than the lower limit, the effect of promoting the decomposition of the initiator is less effective, and the conversion efficiency is not improved. If the upper limit of the range is exceeded, there is a problem of color degradation due to an increase in heat generation in the latter half.

In addition to the protective colloid, the polymerization initiator, and the reducing agent, an antioxidant may further be included. Here, the antioxidant is at least one of a phenol antioxidant, an amine antioxidant, a sulfur antioxidant or a phosphoric acid antioxidant.

The phenolic antioxidant may be triethylene glycol bis- [3- (3-t-butylmethyl-4-hydroxyphenyl) propionate], hydroquinone, p- methoxyphenol, t- n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, 2,5-di-t-butylhydroquinone, 4,4'-butylidenebis Methyl-6-t-butylphenol), t-butyl catechol, 4,4'-thiobis (6-t-butyl- Butylphenol, cyclohexylphenol, 2,2'-methylene-bis (4-methyl-6-t-butylphenol), 4,4'-isopropylidenebisphenol, 4,4'- Butyl-bis (3-methyl-6-t-butylphenol), 1,1,3-tris (2-methyl- Methyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene- ) Propionate] methane, tris (3,5-di-t-butyl-4-hydroxyphenyl) isocyanurate Butylphenol), tris [b- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] iso 2-thiobis (4-methyl-6-t-butylphenol) or a mixture of two or more thereof.

The amine antioxidant may be one or a mixture of N, N-diphenyl-p-phenylenediamine or 4,4-bis (dimethylphenyl) diphenylamine.

The sulfur-based antioxidant may be one kind or a mixture of two or more of dodecyl mercaptan, 1,3-diphenyl-2-thiol, dilauryl thiodipropionate or distearyl diiodopropionate.

The phosphoric acid antioxidant may be one kind or a mixture of two or more of triphenyl phosphite, diphenyldecyl phosphite, phenyl isodecyl phosphite, tri (nonylphenyl) phosphite or triruryl trithiophosphite.

In the present invention, a polymerization modifier, a chain transfer agent, a pH adjuster, a crosslinking agent, an antioxidant, an antistatic agent, a scale inhibitor and a surfactant may be added to the polymerization system before or after polymerization initiation, Or may be continuously added to the polymerization system.

The polymerization temperature used in the present invention varies depending on the kind of the polymerization initiator used, the polymerization method, the use of the polymerization degree regulator, the desired degree of polymerization, etc. In general, the degree of polymerization of the vinyl chloride polymer is determined by the polymerization reaction temperature, Examples Polymerization degree of the polymer greatly influences the processing conditions and the physical properties of the product, so an appropriate polymerization reaction temperature should be selected.

In the above production process, the polymerization temperature of the vinyl chloride-based polymer is 30 to 80 캜, the polymerization time is 2 to 6 hours, and the polymerization pressure is 3 to 15 kg / cm 2. More preferably, The polymerization temperature may be from 57 to 64 占 폚, the pressure may be from 8 to 11 kg / cm2, and the time may be from 3 to 4 hours.

The shape of the stirring device such as the stirrer and the baffle used in the present invention is not particularly limited. For example, as the stirring blades, a paddle type, a pitched paddle type, a bluemagine, Type, a pfaudler type, a turbine type, a propeller type, or the like, or may be used in combination with a stirring blade of a certain kind. As the baffle, a plate type, a cylindrical type, a D type, a loop type, and a finger type are listed.

According to the present invention, in a suspension polymerization method for producing a vinyl chloride polymer, sodium formate aldehyde sulfoxylate is added as a reducing agent capable of activating an initiator without a metal ion in a timely manner to induce rapid consumption of a vinyl chloride monomer, A vinyl chloride resin improved in productivity can be produced which does not use metal ions and does not deteriorate color.

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 and scope of the invention as defined by the appended claims. Changes and modifications may fall within the scope of the appended claims.

Example  One

In a 5 L high-pressure reactor, 1.8 kg of deionized water, 800 ppm of tert-butyl peroxy neodecanoate (BND), 80% of hydration and a viscosity of 30 cps at 4% 950 ppm of vinyl alcohol was fed into the reactor, and a vacuum was applied. Then, 1.2 kg of vinyl chloride monomer was added thereto. The initial reaction temperature was raised to 58 ° C to maintain the polymerization reaction throughout the polymerization reaction. 120 kg of a vinyl chloride monomer was further added.

At the end of the addition of the vinyl chloride monomer, 80 ppm (part per million) of tertiary butyl peroxyneodecanoate and 80 ppm of SFS were added all at once.

When the polymerization reactor pressure was reduced by about 1.0 kg / cm ² (ΔP), the reaction was stopped and unreacted monomers were recovered and the polymer slurry was recovered in the polymerization reactor.

The thus obtained slurry was dried in a convention oven for 24 hours to obtain a vinyl chloride polymer.

Example  2

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the initiator tertiary-butyl peroxyneodecanoate added in Example 1 and the SFS content were changed to 160 ppm, respectively.

Example  3

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the initiator tertiary-butyl peroxyneodecanoate added in Example 1 was replaced with 240 ppm of SFS.

Example  4

Except that di-3,5,5-trimethylhexanoyl peroxide was used in place of tertiary-butyl peroxyneodecanoate as an initiator to be added in Example 1, a vinyl chloride polymer .

Example  5

In Example 1, di-3,5,5-trimethylhexanoyl peroxide was used instead of tertiary-butyl peroxyneodecanoate as an additional initiator, and di-3,5,5-trimethylhexanoyl A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the peroxide and SFS contents were changed to 160 ppm, respectively.

Example  6

In Example 1, di-3,5,5-trimethylhexanoyl peroxide was used instead of tertiary-butyl peroxyneodecanoate as an additional initiator, and di-3,5,5-trimethylhexanoyl A vinyl chloride polymer was prepared in the same manner as in Example 1, except that the peroxide and SFS contents were changed to 240 ppm, respectively.

Example  7

Except that dilauryl peroxide was used in place of tertiary-butyl peroxyneodecanoate as an additional initiator in Example 1, and the dilauryl peroxide and SFS contents were respectively replaced by 240 ppm. 1, a vinyl chloride polymer was prepared.

Comparative Example  One

A vinyl chloride polymer was prepared in the same manner as in Example 1 except that no additional initiator and SFS were added to the conventional vinyl chloride polymer production method.

Comparative Example  2

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 240 ppm of tertiary-butyl peroxyneodecanoate was added additionally without addition of SFS in order to compare with the conventional vinyl chloride polymer production method .

Comparative Example  3

In order to compare with the conventional method of producing a vinyl chloride polymer, the same procedure as in Example 1 was repeated except that 240 ppm of di-3,5,5-trimethylhexanoyl peroxide was added additionally without further addition of SFS, Vinyl polymer.

Comparative Example  4

A vinyl chloride polymer was prepared in the same manner as in Example 1, except that 240 ppm of dilauryl peroxide was further added without further addition of SFS in order to compare with the conventional vinyl chloride polymer production method.

Comparative Example  5

A vinyl chloride polymer was prepared in the same manner as in Example 1 except that 80 ppm of ascorbic acid was added instead of SFS used as a reducing agent in Example 1 in order to compare with the conventional vinyl chloride polymer production method.

[Test Example]

The average particle diameter, degree of polymerization and whiteness of the vinyl chloride resin prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are summarized in Tables 1 and 2 below.

* Measurement of polymerization degree: Measured by ASTM D-1243-79.

* Whiteness measurement: A masterbatch was added to a vinyl chloride resin, and the sheet was prepared by mixing with a roll mill for 5 minutes, and measured by a whiteness measuring instrument, Nippon Denshoku NR-3000.

Metrics Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Polymerization time (min) 197 197 197 197 197 197 197 Conversion Rate (%) 85.0 86.4 88.0 85.3 87.2 89.0 86.3 Degree of polymerization 1000 1000 980 1020 1000 1000 980 Whiteness 70.3 71.2 71.0 70.1 70.1 70.2 69.9 (G / cc) 0.485 0.484 0.485 0.485 0.486 0.483 0.483 Average particle diameter (占 퐉) 162 160 165 163 169 161 162

Metrics Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Polymerization time (min) 197 197 197 197 197 Conversion Rate (%) 84.0 84.1 84.1 84.5 84.0 Degree of polymerization 1000 1000 1000 1000 1000 Whiteness 70.3 68.2 67.6 68.1 68.3 (G / cc) 0.485 0.489 0.481 0.485 0.487 Average particle diameter (占 퐉) 162 160 165 162 165

As shown in Tables 1 and 2, it can be seen that the polymerization conversions of Examples 1 to 7 were significantly increased compared with Comparative Examples. This is because SFS activated the reaction by promoting decomposition of the initiator.

Especially, as the content of initiator and SFS increased, the conversion rate increased, and the physical properties such as polymerization degree, whiteness and bulk specificity were not affected.

On the other hand, the difference depending on the kind of the initiator was not large.

In Comparative Example 1, there was no addition of initiator and SFS. In Comparative Examples 2 and 4, the addition initiator type was changed and SFS was not added. In these Comparative Examples, SFS was not added, The productivity was not increased, and the initiator which was not decomposed remained in the vinyl chloride polymer as a result, resulting in a decrease in whiteness.

In addition, in Comparative Example 5, ascorbic acid was replaced with an initiator instead of SFS. As a result, unlike the examples using SFS, it was confirmed that no additional initiator was activated without metal ion alone.

Claims (10)

A vinyl chloride polymer is prepared by suspension polymerization of a vinyl chloride monomer in the presence of a polymerization dispersant and a polymerization initiator, wherein the vinyl chloride monomer is reacted with a vinyl chloride monomer, a second polymerization initiator and sodium formaldehyde sulfide Wherein the polyvinyl chloride-based polymer is further added with sodium formaldehyde sulfoxylate. delete The method according to claim 1,
Wherein the suspension polymerization is carried out at a polymerization temperature of 30 to 80 占 폚 and a polymerization pressure of 3 to 15 kg / cm2 for 2 to 6 hours.
The method according to claim 1,
Wherein the content of the additional vinyl chloride monomer is in the range of 5 to 20 parts by weight based on 100 parts by weight of the vinyl chloride monomer to be charged before the start of the polymerization. The method according to claim 1,
Wherein the polymerization initiator and the second polymerization initiator are at least one selected from the group consisting of diacyl peroxide type, peroxydicarbonate type, peroxy ester type and sulfate type.
The method according to claim 1,
Wherein the polymerization initiator introduced before the initiation of the suspension polymerization is charged into the range of 0.02 to 0.2 part by weight based on 100 parts by weight of the vinyl chloride monomer charged before the start of the polymerization. The method according to claim 1,
Wherein the content of the second polymerization initiator to be added is in the range of 0.02 to 0.25 parts by weight based on 100 parts by weight of the additional amount of the vinyl chloride monomer.
The method according to claim 1,
Wherein the polymerization dispersant is a protective colloid assistant and is put into the range of 0.05 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer to be added before the start of the polymerization. 9. The method of claim 8,
Wherein the protective colloid coagulation agent has a hydration degree of 30 to 95% by weight and a viscosity of 5 to 60 cps at 4% aqueous solution at room temperature, a hydroxyl value of 5 to 40% by weight of a propylhydroxyl group and a 2% aqueous solution A cellulose having a viscosity of 10 to 10,000 cps, and a polymer of an unsaturated organic acid.
The method according to claim 1,
Wherein the content of the sodium formaldehyde sulfoxylate is in the range of 50 to 150 parts by weight based on 100 parts by weight of the added second polymerization initiator.