KR101553099B1 - Method of preparing vinyl chloride resin having excellent processibility and productivity - Google Patents

Abstract

The present invention relates to a vinyl chloride resin composition having a high apparent specific gravity and at the same time having a small amount of fish eye and having both processability and productivity in a batch suspension polymerization process for producing a vinyl chloride resin by adding a dispersant having a hydration degree of 85% Can be produced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin having excellent processability and productivity,

More particularly, the present invention relates to a process for producing a vinyl chloride resin by suspension polymerization of a vinyl chloride monomer in the presence of a protective colloid preparation and a polymerization initiator, To a suspension polymerization method of a vinyl chloride resin which is improved in productivity.

BACKGROUND OF THE INVENTION [0002] Vinyl chloride resins are used in a wide variety of fields such as pipes, films, window frames, wire covers, wrap films, sheets and the like because of their low cost and excellent quality balance.

The fish-eye is the most important quality of the quality of the vinyl chloride resin and is a measure of the workability of the resin. And the apparent specific gravity is one of the important quality of vinyl chloride resin together with the quality of PVC resin which is directly connected with productivity.

In order to improve the specific gravity, there is a method of adding a specific protective colloid or changing the process conditions to decrease the particle size and increase the porosity. As a method of improving the apparent specific gravity, there is a method in which a vinyl chloride monomer is continuously added during polymerization, There is a method of using a dispersant having a high degree of hydration.

In recent years, attempts have been made to obtain a high apparent weight and a relatively low specific weight by dividing or continuously injecting a dispersant having various hydrates and molecular weights. However, when the porosity is increased by decreasing the porosity, the apparent specific gravity is decreased, so that it is difficult to obtain the low visible eye and the high apparent specific gravity at the same time.

For example, U.S. Patent No. 5,096,988 of Shinetsu has obtained a high apparent specific gravity by adding a dispersant having a hydration degree of 75% or more and 85% or less at the beginning and the middle of the reaction, but a problem of a large number of fish eyes there was.

In addition, US Patent No. 5,204,421 issued to Shinetsu Co., Ltd. discloses a dispersant having a degree of hydration of 20% or more and 55% or less in hydration degree in the early stage and middle stage of the reaction to obtain a vinyl chloride resin having a high plasticizer absorptivity and a low water- However, productivity was low due to the low apparent weight.

Likewise, in the United States Patent No. 7,001,960 B2 of Shin-Etsu Chemical Co., Ltd., a dispersant having a low water-solubility and a degree of hydration of 20% or more and 57% or less was continuously fed from the beginning of the reaction to the mid-reaction stage to obtain a vinyl chloride- There was also a problem with a low apparent weight.

SUMMARY OF THE INVENTION The object of the present invention is to provide a method for preparing a vinyl chloride resin by suspension polymerization of a vinyl chloride monomer in the presence of a protective colloid assistant and a polymerization initiator, Which is capable of improving the workability of the vinyl chloride resin to improve the glossiness and to increase the apparent specific gravity, thereby improving the productivity of the vinyl chloride resin.

The above object 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 method for producing a vinyl chloride resin by suspension polymerization, wherein the suspension polymerization is carried out at a temperature of 70 to 100 캜 at a high temperature, And 98% of a dispersant is added to the mixture to carry out the polymerization.

According to the suspension polymerization method of the vinyl chloride resin of the present invention, it is possible to provide a suspension polymerization method for producing an excellent high-quality vinyl chloride resin having a small fish-eye and high apparent specific gravity.

DISCLOSURE OF THE INVENTION The inventors of the present invention conducted intensive studies to solve the problems of the prior art as described above, and found that when a dispersant having a hydration degree of 85% or more, which is used for obtaining a high apparent specific gravity, , And the result was obtained that a small number of bright eyes were obtained at the same time.

In the present invention, in the process for producing a vinyl chloride resin by suspension polymerization, the suspension polymerization is carried out at a high polymerization temperature of 70 to 100 캜 in the vinyl chloride monomer, do.

One embodiment of the present invention is a method for producing a vinyl chloride resin by suspension polymerization, wherein the suspension polymerization is carried out at a temperature of 70 to 100 캜 at a high-temperature polymerization water, and when the polymerization conversion is 10 to 30% 98% of dispersant is added to perform polymerization.

Another embodiment of the present invention is a method for producing a vinyl chloride resin by suspension polymerization, wherein the suspension polymerization is carried out at a temperature of 70 to 100 캜 at a high temperature, and when polymerization conversion is 10 to 30% The dispersing agent having a degree of hydration of 85% to 98% is added in portions to effect polymerization.

The high-temperature polymerization reactor is charged in a reactor within a range of 70 to 100 ° C, and then the polymerization reaction is immediately initiated by the introduction of a polymerization initiator, thereby maximizing the economic effect.

The dispersant having a degree of hydration of 85% to 98% is preferably a vinyl alcohol resin having a degree of hydration of 85% to 98%, and the amount of the dispersant having a degree of hydration of 85% to 98% Preferably 0.001 to 0.01 part by weight, more preferably 0.006 to 0.008 part by weight. When the amount is less than 0.001 part by weight, not only the processability but also scale may occur. If the amount is more than 0.01 part by weight, economical efficiency is low.

Specifically, it is preferable that the suspension polymerization is carried out by mixing the high-temperature polymerized water with a vinyl chloride monomer and a protective colloid assistant, and adding a polymerization initiator to the mixed solution to polymerize. The dispersing agent having a hydration degree of 85% or more is mixed with the protective colloid assistant and then added thereto or polymerized in the middle of the polymerization reaction. The suspension polymerization is preferably carried out in the presence of 120 to 150 parts by weight of high-temperature polymerization water, 0.03 to 5 parts by weight of a protective colloid preparation, and 0.02 to 0.2 parts by weight of a polymerization initiator, based on 100 parts by weight of the vinyl chloride monomer.

For reference, the vinyl chloride-based resin of the present invention is a mixture of a resin composed mainly of a vinyl chloride monomer and a vinyl monomer mainly composed of a vinyl chloride monomer and a copolymerizable vinyl monomer (the content of the vinyl chloride monomer in the resin composition is 50 Weight% or more).

In addition, in the present invention, the protective colloid preparation used for the purpose of stably maintaining the production process of vinyl chloride resin and obtaining stable particles has a hydration degree of 30 to 90% by weight and a viscosity of 4% Wherein the viscosity of the 2% aqueous solution measured at room temperature is 10 to 20,000 cps and the unsaturated organic acid is selected from the group consisting of 15 to 40 wt% of a methoxy group and 3 to 20 wt% Or more. It is preferable that the protective colloid preparation contains a vinyl alcohol resin having a degree of hydration of 85 to 98% and a vinyl alcohol resin having a degree of hydration of 50 to 60%. Within this range, have. In the present invention, a dispersant having a degree of hydration of 85% or more and a dispersant having a degree of hydration of 60% or less are mixed in a weight ratio of 0.3 to 1.5, and the mixture is used .

The protective colloid aid is preferably included in an amount of 0.03 to 5 parts by weight, more preferably 0.05 to 2.5 parts by weight, based on 100 parts by weight of the total monomers. When used in the above amount, no coarse particles are formed and no fish eye is generated.

The high water-dispersibility dispersing agent usable in the present invention is preferably a vinyl alcohol-based resin having a hydration degree of 85 to 98%. When the water-solubility is lower than the above range, the effect of reducing fish eye and initial apparent specific gravity is insufficient, , The plasticizer absorption rate is lowered and the amount of the plasticizer is increased. It is preferable that the conversion rate is 10% to 30% at the time when the high water solubility dispersing agent is added and added. When the conversion rate is lower than the above conversion rate, a small apparent specific gravity and a large amount of phosphorus are generated as in the case of using a high water-dispersibility dispersing agent at the beginning without carrying out a batch addition, There is a risk of obtaining a polyvinyl chloride-based resin that falls.

Further, as the polymerization initiator usable in the present invention, diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethylhexanoyl peroxide and diaryl peroxide, diisopropyl Peroxydicarbonates such as peroxydicarbonate, di-sec-butylperoxydicarbonate and di-2-ethylhexyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t Peroxyesters such as amyl peroxyneodecanoate, cumyl peroxyneodecanoate, cumyl peroxyneoheptanoate, and 1,1,3,3-tetramethylbutyl peroxyneodecanoate, azobis -2,4-dimethylvaleronitrile, and sulfates such as potassium persulfate and ammonium persulfate, and they may be used alone or in combination of two or more thereof. The amount of the initiator to be used is generally from 0.02 to 0.2 parts by weight, and most preferably from 0.04 to 0.12 parts by weight, based on 100 parts by weight of the total charged monomers. The use of parts is preferable. When the initiator is used in an amount less than the proper amount, the reaction time is delayed and the productivity is decreased. When the amount of initiator is excessively larger than the proper amount, the initiator is not completely consumed during the polymerization and remains in the final resin product.

Examples of the antioxidant that can be used before the reaction is stopped in the present invention include triethylene glycol-bis-3- (3-t-butyl- (4-hydroxy-5-methylphenyl) propionate, hydroquinone, p-methoxyphenol, t-butylhydroxyanisole, n- Butylphenyl) propionate, 2,5-di-t-butylhydroquinone, 4,4-butylidenebis (3-methyl-6-t-butylphenol), t- Compounds such as N, N-diphenyl-p-phenylenediamine and 4,4-bis (dimethylbenzyl) diphenylamine, Dodecyl mercaptan, 1,2-diphenyl-2-thiol, and the like, or a mixture of two or more thereof.

On the other hand, as the reactor used in the present invention, it is sufficient to use a stirrer generally used in the suspension polymerization of a vinyl chloride resin. Specific examples of the stirrer include stir paddle type paddle type, pitched type a baffler type, a turbine type, a propeller type or the like may be used as the agitator in combination with agitating blades of a baffle type, a paddle type, a bloomer gin type, a pfaudler type, a turbine type, A plate, a cylinder, a D, a loop, a finger, or the like.

The suspension polymerization is preferably carried out at a polymerization temperature of 55 to 65 占 폚.

The vinyl chloride resin slurry may be dried under a normal reaction condition with a fluidized bed dryer to produce a final vinyl chloride resin.

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 scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example  One

Into a 1 m ³ internal volume reactor equipped with a reflux condenser was charged 320 kg of deionized water at 80 ° C, 123 g of polyvinyl alcohol having a hydration degree of 72%, 86 g of polyvinyl alcohol having a hydration degree of 55% and 17 g of hydroxypropylmethyl cellulose were charged into a reactor , 300 kg of a vinyl chloride monomer was added, and then 173 g of t-butyl peroxyneodecanoate was added to initiate the reaction.

During the entire polymerization reaction, the reaction was allowed to proceed while maintaining the reaction temperature at 64 占 폚. When the conversion of polymerization reached approximately 10%, 26 g of polyvinyl alcohol having a degree of hydration of 87% was added. Next, (2,2,6,6-tetramethylpiperidin-1-yl) propane was used as an antioxidant at the time when the pressure of the polymerization reactor reached 8.0 kg / cm ² (when the polymerization conversion ratio corresponded to about 85% 5 g of oxyl and 36 g of triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate were added and the unreacted monomers were recovered and the resin slurry was recovered in a polymerization reactor .

The slurry thus obtained was dried in a fluidized bed drier by a conventional method to obtain a vinyl chloride resin.

Example  2

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% at the time of the middle injection was added in the above Example 1 and evaluated.

Example  3

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 95% at the time of the middle injection was added in the above Example 1 and evaluated.

Example  4

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% was added when the conversion ratio in Example 1 was approximately 20%.

Example  5

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% was added when the conversion ratio in Example 1 was approximately 30%.

Example  6

Polymerization was carried out under the same conditions as in Example 1 except that 13 g of polyvinyl alcohol having a degree of hydration of 90% was added at a conversion rate of 10% before the introduction of the vinyl chloride monomer in Example 1.

Example  7

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% at the time of the middle injection was added in the above Example 1 and evaluated.

Example  8

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% was added thereto while maintaining the polymerization temperature at 57 캜 in the above-mentioned Example 1 and evaluated.

Example  9

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 95% was added while the polymerization temperature was maintained at 57 캜 in the first example.

Example  10

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% was added when the polymerization temperature was maintained at 57 캜 and the conversion was approximately 20% .

Example  11

Polymerization was carried out under the same conditions as in Example 1 except that 26 g of polyvinyl alcohol having a degree of hydration of 90% was added when the polymerization temperature was maintained at 57 캜 and the conversion was approximately 30% .

Example  12

The procedure of Example 1 was repeated except that the polymerization temperature was maintained at 57 占 폚 and 13 g of polyvinyl alcohol having a degree of hydration of 90% at a conversion rate of 10% was added before the addition of the vinyl chloride monomer, Polymerization was carried out under the conditions and evaluated.

Comparative Example  One

390 kg of deionized water at 80 ° C was charged into a 1 m ³ internal volume reactor having a reflux condenser, ²⁶ g of polyvinyl alcohol having a degree of hydration of 87%, 100 g of polyvinyl alcohol having a degree of hydration of 55% and 50 g of hydroxypropylmethyl cellulose were placed in a reactor , 300 kg of a vinyl chloride monomer was added, and then 173 g of t-butyl peroxyneodecanoate was added to initiate the reaction.

The polymerization reaction allowed to proceed the reaction while keeping the reaction temperature at 64 ℃ during the entire process, as an antioxidant in (a time point corresponding to approximately 85% of polymerization conversion rate) the pressure of the polymerization reactor when you reach 8.0kg / cm ^{2 (2} 5 g of triethylene glycol-bis-3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate The unreacted monomers were then recovered and the resin slurry was recovered in the polymerization reactor. The slurry thus obtained was dried in a fluidized bed drier by a conventional method to obtain a vinyl chloride resin.

Comparative Example  2

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 90% of polyvinyl alcohol having a degree of hydration of 87% instead of 87% of polyvinyl alcohol was added in Comparative Example 1 and evaluated.

Comparative Example  3

Polymerization was carried out under the same conditions as in Comparative Example 1, except that 87% polyvinyl alcohol was not added in the degree of hydration in Comparative Example 1 and evaluated.

Comparative Example  4

Polymerization was carried out under the same conditions as in Comparative Example 1 except that polyvinyl alcohol having a degree of hydration of 87% was added at a conversion of 5% in Comparative Example 1, and evaluated.

Comparative Example  5

Polymerization was carried out under the same conditions as in Comparative Example 1, except that polyvinyl alcohol having a degree of hydration of 87% was added at a conversion of 50% in Comparative Example 1, and evaluated.

Comparative Example  6

Polymerization was carried out under the same conditions as in Comparative Example 1, except that the polymerization temperature was maintained at 57 占 폚 in Comparative Example 1, and evaluated.

Comparative Example  7

Polymerization was carried out under the same conditions as in Comparative Example 1 except that the polymerization temperature was maintained at 57 占 폚 and the degree of hydration was changed to 87% of polyvinyl alcohol instead of polyvinyl alcohol of 90% and 26 g of polyvinyl alcohol. Respectively.

Comparative Example  8

Polymerization was carried out under the same conditions as in Comparative Example 1, except that the polymerization temperature was maintained at 57 占 폚 and 87% polyvinyl alcohol was not added.

Comparative Example  9

Polymerization was carried out under the same conditions as in Comparative Example 1, except that the polymerization temperature was maintained at 57 占 폚 and the degree of hydration was 87% polyvinyl alcohol at a conversion of 5%.

Comparative Example  10

Polymerization was carried out under the same conditions as in Comparative Example 1 except that the polymerization temperature was maintained at 57 占 폚 and the degree of hydration was 87% polyvinyl alcohol at a conversion of 50%.

[Test Example]

The physical properties of the vinyl chloride resin prepared in Examples 1 to 12 and Comparative Examples 1 to 10 and the polymerization conversion during the polymerization were measured by the following methods, and the results are shown in Tables 1 and 2 below.

* Measurement of polymerization conversion ratio: Measurement was carried out using a butane tracer equipped with gas chromatography. If the polymerization conversion curve according to the ratio of the vinyl chloride monomer to the butane over time under the constant polymerization conditions is prepared every polymerization conditions, the polymerization conversion ratio according to the polymerization conditions can be measured with high accuracy.

* Measurement of polymerization degree: Measured by ASTM D1 243-79.

* Apparent Specific Gravity: Measured by ASTM D1 895-89.

* Plasticizer absorption rate: The amount of DOP absorbed by the sample in accordance with ASTM D3367-95 is expressed in weight% with respect to the sample before absorption.

* Particle distribution measurement: The weight percentages of the samples having passed through the sieve of # 60 and # 200 were measured according to the particle distribution measurement method of ASTM D1 705, and measured.

Fish-eye water: 100 parts by weight of a vinyl chloride resin, 45 parts by weight of DOP, 0.1 part by weight of barium stearate, 0.2 part by weight of a tin stabilizer and 0.1 part by weight of carbon black were melt- After mixing and kneading for 5 minutes, a sheet having a thickness of 0.3 mm was formed, and this sheet was expressed by the number of white transparent particles in 400 cm ² .

Evaluation of initial coloring property: 1 part by weight of a tin stabilizer, 0.5 part by weight of a lead stabilizer, 1.5 parts by weight of a stabilizer, and 45 parts by weight of a plasticizer were compounded in 100 parts by weight of the obtained resin and kneaded using a roll at 150 DEG C for 5 minutes. . The sheet was cut and overlapped, and a compression sheet was formed through press molding. This was visually observed and evaluated according to the following criteria.

○: When the degree of coloration is the same and there is no problem in practical use

X: The degree of discoloration relative to Comparative Example 1 is clearly different, and when the tone is different from the practical level

Metrics Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Degree of polymerization 800 800 800 800 800 800 Apparent Specific Gravity (g / cc) 0.471 0.492 0.475 0.489 0.535 0.477 Plasticizer absorption rate
(%) 21.1 22.8 20.1 19.3 18.8 20.0 Particle Size Distribution # 60
(%) 100 100 100 100 100 100 Particle Size Distribution # 200
(%) 2.0 1.9 2.2 1.2 0.7 0.6 Fisheye (Ea) 6 5 6 5 6 6 Initial coloring degree ○ ○ ○ ○ ○ ○ Metrics Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Degree of polymerization 1030 1030 1030 1030 1030 1030 Apparent Specific Gravity (g / cc) 0.463 0.479 0.465 0.472 0.522 0.468 Plasticizer absorption rate 24.3 26.2 23.6 22.9 22.3 23.4 Particle Size Distribution # 60
(%) 100 100 100 100 100 100 Particle Size Distribution # 200
(%) 1.2 1.0 1.5 0.7 0.5 1.0 Fisheye (Ea) 4 4 5 4 4 5 Initial coloring degree ○ ○ ○ ○ ○ ○

Metrics Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Degree of polymerization 800 800
Over size occurs 800
Over size occurs Apparent Specific Gravity (g / cc) 0.468 0.472 0.467 Plasticizer absorption rate
(%) 16.7 16.2 16.6 Particle Size Distribution # 60
(%) 100 100 100 Particle Size Distribution # 200
(%) 2.9 3.4 3.0 Fisheye (Ea) 19 22 20 Initial coloring degree ○ X ○ Metrics Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Degree of polymerization 1030 1030
Over size occurs 1030
Over size occurs Apparent Specific Gravity (g / cc) 0.431 0.443 0.428 Plasticizer absorption rate 19.3 18.7 19.1 Particle Size Distribution # 60
(%) 100 100 100 Particle Size Distribution # 200
(%) 3.0 4.1 2.8 Fisheye (Ea) 15 18 16 Initial coloring degree ○ ○ ○

As shown in Table 1, in Examples 1 to 12 in which polymerization was started using high-temperature polymerized water and a high-solubility dispersant was added in the middle of the polymerization reaction or in the early stage and the middle stage of the polymerization reaction, improvements The result can be confirmed. The particle size distribution is reduced, the initial coloring degree is improved, the apparent specific gravity is increased, the plasticizer absorption rate is also increased, and the fishy eye is also reduced.

On the other hand, as shown in Table 2, in Comparative Examples 1 to 10 in which the high water-solubility dispersing agent was used initially or not at all, the physical properties of fish eyes were poor and the volume specific gravity was also small. When the dispersing agent of high water solubility was used in the early stage, a low plasticizer absorption rate resulted in an increase in the number of fish eyes and a wider particle distribution, resulting in a decrease in initial coloring degree. When a high water-solubility dispersing agent was not used or when the conversion was 50%, a vinyl chloride resin having a large particle diameter of 500 탆 or more was obtained and a large amount of scale appeared.

Claims (10)

In a method for producing a vinyl chloride resin by suspension polymerization,
Wherein the suspension polymerization is carried out by using high temperature polymerized water at 70 to 100 DEG C and adding a dispersant having a degree of hydration of 85% to 98% before the introduction of the vinyl chloride monomer and at a polymerization conversion rate of 10 to 30% A method for producing a vinyl chloride resin. delete The method according to claim 1,
Wherein the dispersant having a degree of hydration of 85% to 98% is a vinyl alcohol resin having a degree of hydration of 85% to 98%. The method according to claim 1,
Wherein the suspension polymerization is carried out by introducing high temperature polymerization water at 70 to 100 占 폚 and polymerizing by the introduction of a polymerization initiator. The method according to claim 1,
Wherein the suspension polymerization is carried out by mixing a high-temperature polymerized water with a vinyl chloride monomer and a protective colloid assistant, and introducing a polymerization initiator into the mixed solution to polymerize the vinyl chloride resin. 6. The method of claim 5,
Wherein the protective colloid coagulation agent is a polyvinyl alcohol resin having a hydration degree of 30 to 90% by weight and a viscosity of 5 to 100 cps at 4% aqueous solution at room temperature, 15 to 40% by weight of methoxy group, 3 to 20% by weight of hydroxyl group- Wherein the viscosity of the 2% aqueous solution is 10 to 20,000 cps, and the unsaturated organic acid is at least one selected from the group consisting of cellulose and unsaturated organic acids. 6. The method of claim 5,
Wherein the protective colloid assistant is a vinyl alcohol resin having a degree of hydration of 85 to 98% and a vinyl alcohol resin having a degree of hydration of 50 to 60%. The method according to claim 1,
Wherein the amount of the dispersant to be added is from 0.001 to 0.01 parts by weight per 100 parts by weight of the vinyl chloride monomer. 6. The method of claim 5,
Wherein the suspension polymerization is carried out in an amount of 120 to 150 parts by weight of high-temperature polymerization water, 0.03 to 5 parts by weight of a protective colloid preparation, and 0.02 to 0.2 part by weight of a polymerization initiator, based on 100 parts by weight of the vinyl chloride monomer. ≪ / RTI > The method according to claim 1,
Wherein the suspension polymerization is carried out at a polymerization temperature of 55 to 65 占 폚.