KR101056958B1 - Method for preparing vinyl chloride polymer by additional addition of water soluble initiator - Google Patents

Abstract

The present invention relates to a method for producing a vinyl chloride-based polymer, and more particularly, to a method for producing a vinyl chloride-based polymer comprising a vinyl chloride monomer, a protective colloid aid, a polymerization initiator, and a hydrogen ion concentration regulator, wherein a water-soluble peroxide is added. It relates to a method for producing a vinyl chloride-based polymer, characterized in that the input.

According to the present invention, by using the effective heat removal capacity of the reactor more effectively, not only shortening the polymerization reaction time but also increasing the polymerization conversion rate to increase the amount of output per batch, further improve the polymerization productivity, whiskey and initial colorability, etc. It is effective to provide a high quality vinyl chloride polymer having a stable quality.

Water soluble peroxide, polymerization initiator, polymerization conversion rate, vinyl chloride polymer

Description

Process for producing vinyl chloride polymer by additional addition of water-soluble initiator {Process for Vinyl Chloride Polymer by Addition of Water-soluble Initiator}

The present invention relates to a method for producing a vinyl chloride-based polymer, and more particularly, not only shortening the polymerization reaction time but also increasing the conversion efficiency to increase the amount of output per batch to further improve the polymerization productivity, And a method for producing a high quality vinyl chloride polymer having stable quality such as initial coloring property.

Vinyl chloride-based polymers are inexpensive and have a good quality balance and are used in various fields such as pipes, films and wire coatings.

Recently, there is a need to reduce the production cost of vinyl chloride polymers due to the increase in oil prices. In this way, efforts have been made to improve the polymerization productivity. Producing is the most common way. In addition, there is a need for a method of producing a stable polymer such as a degree of polymerization of a vinyl chloride-based polymer, whiskey and initial coloring properties. However, although the polymerization productivity is excellent in the manufacturing method of the conventionally known vinyl chloride type polymer, there exists an inadequate problem to ensure stable quality. Moreover, it concentrates on shortening of polymerization reaction time, and has the limitation in the improvement of polymerization productivity.

In order to shorten the polymerization reaction time of the vinyl chloride polymer, US Patent No. 2004-0034181 describes a method using a combination of organic initiators having a fast half-life. However, although the reaction time may be shortened by using the initiator having a short half-life by the above method, the polymerization productivity may be increased to a certain extent, considering that the vinyl chloride polymer is prepared by radical polymerization, Since the growth is rapid, and the growth is gradually weakened toward the second half of the polymerization, there is a problem in that the initial pigmentation due to the increase in the amount of fine particles or the increase of the fine particles occurs.

In addition, Japanese Patent 1998-338701 describes a method of shortening the polymerization reaction time by using an oil-soluble initiator and a water-soluble initiator in combination with the initial polymerization. However, although the reaction time shortening effect by the above method can be expected to some extent, in the production of vinyl chloride-based polymers, vinyl chloride monomer is a substance having useful properties, and in the initial stage of polymerization, vinyl chloride monomer and deionized water, which is polymerized water, Since most of the unreacted vinyl chloride monomer which is present in the phase separated state and then the polymerization reaction proceeds and the polymerization conversion rate of 60% or more is not converted into the polymer is dissolved in the aqueous phase, the water-soluble initiator used together with the oil-soluble initiator at the beginning of the reaction. In addition, the effect of shortening the reaction time may not be large, and microparticles generated by the water-soluble initiator in the initial stage of the polymerization reaction may stick to the inner wall of the reactor and cause scale generation.

The technical problem to be achieved by the present invention is to provide a method for producing a high-quality vinyl chloride-based polymer with improved polymerization productivity and stable quality such as whiskey and initial coloring property.

In order to achieve the above technical object,

A method for preparing a vinyl chloride polymer by suspending and polymerizing a vinyl chloride monomer in the presence of a protective colloid preparation and an oil-soluble polymerization initiator, wherein a water-soluble polymerization initiator is added in a period of 60% to 75% after polymerization conversion of the vinyl chloride monomer. It provides a vinyl chloride polymer manufacturing method comprising the step of adding.

According to the present invention, it is possible to more effectively use the reactor effective heat removal capacity to shorten the polymerization reaction time, as well as increase the polymerization conversion efficiency to increase the amount of output per batch, further improve the polymerization productivity, whiskey and initial colorability It is effective to provide a high quality vinyl chloride polymer having stable quality.

Hereinafter, the present invention will be described in detail.

First, 100 to 150 parts by weight of a solvent, 0.03 to 3 parts by weight of a protective colloid preparation, and 0.02 to 0.15 parts by weight of an oil-soluble polymerization initiator with respect to 100 parts by weight of a vinyl chloride monomer (or a mixture with a comonomer copolymerizable with a vinyl chloride monomer) in the reactor. Input.

Vinyl chloride-based polymers are not only resins composed of purely vinyl chloride monomers, but also mixtures with vinyl-based monomers copolymerizable with vinyl chloride monomers, provided that the vinyl chloride monomer content in the polymer composition is 50% by weight or more. Also includes. Vinyl monomers copolymerizable with vinyl chloride monomers include olefin compounds such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated nitriles such as acrylonitrile, vinyl alkyls such as vinyl methyl ether and vinyl ethyl ether. The monomers generally copolymerizable with vinyl chloride, such as unsaturated fatty acids, such as ether, acrylic acid, itaconic acid itaconic acid, maleic acid, and anhydrides of these fatty acids, are mentioned, These can be used individually or in combination of 2 or more types.

In the present invention, the protective colloid preparation used to stably maintain the vinyl chloride polymer manufacturing process and to obtain stable particles includes a vinyl alcohol having a hydration degree of 30 to 95 wt% and a viscosity of 4% aqueous solution at 5 to 60 cps at room temperature. A polymer of cellulose having a viscosity of 10% to 10,000 cps or a polymer of an unsaturated organic acid may be used. Cholic acid polymers, fumaric acid polymers, maleic acid polymers, succinic acid polymers, gelatin, and the like, may be used alone or in combination of two or more thereof. The addition amount of the protective colloid preparation is appropriate to use 0.03 to 3 parts by weight based on 100 parts by weight of the total input monomer, more preferably 0.05 to 2 parts by weight level is effective. When used in the above content does not form coarse particles does not occur whiskey, there is no increase in fine particles has an excellent initial coloring properties.

As the oil-soluble polymerization initiator in the polymerization reaction of the present invention, an organic peroxide, azo compound or sulfate system may be used. Specifically, dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethyl nucleoanoyl peroxide, dilau Diacyl peroxides such as royl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, or t-butylperoxy pivalate peroxy esters such as t-butyl peroxy neodecanoate, azo compounds such as azobis-2,4-dimethylvaleronitrile, sulfates such as potassium persulfate and ammonium persulfate, and the like, Use alone or in combination of two or more thereof is possible. The amount of use is determined by factors such as manufacturing process, productivity, and quality. Generally, the total amount of initiator can be used in an amount of 0.02 to 0.15 parts by weight, and most preferably 0.04 to 0.1 parts by weight based on 100 parts by weight of the total monomer. Use is preferred. When the amount of the oil-soluble polymerization initiator is less than the proper amount, the reaction time is delayed, and productivity is lowered. When the amount of the oil-soluble polymerization initiator is used, the polymerization initiator is not completely consumed during the polymerization process and remains in the final resin product to degrade the thermal stability and color quality of the resin.

In the polymerization reaction of the present invention, a hydrogen ion concentration regulator may be further added. Available hydrogen ion concentration regulators include sodium bicarbonate (NaHCO ₃ ), sodium borate (Na ₂ B ₄ O ₇ ), dibasic sodium phosphate (Na ₂ HPO ₄ ), sodium carbonate (Na ₂ CO ₃ ), potassium dihydrogen phosphate ( KH ₂ PO ₄ ), ammonium hydroxide (NH ₄ OH), potassium tartarate (KHC ₄ H ₄ O ₆ ), potassium hydrogen phthalate (KHC ₈ H ₄ O ₄ ) or calcium hydroxide (Ca (OH) ₂ ), among others. Single or mixed use of two or more types is also possible.

The hydrogen ion concentration regulator may be included in an amount of 0.01 to 1.0 parts by weight based on 100 parts by weight of the total monomers. When used in the above content does not form coarse particles does not occur whiskey, there is no effect that the fine particles are increased there is excellent initial coloring properties.

In addition, the present invention is characterized in that the addition of a water-soluble polymerization initiator in the period from the maximum calorific value of the polymerization reaction until the polymerization pressure begins to drop.

Although there may be a difference depending on the type and the input amount of the water-soluble polymerization initiator to be used, Xc (the point where the maximum calorific value appears) usually appears around 60% of the polymerization conversion rate. Therefore, the addition of the initiator in the vicinity may exceed the reactor effective heat removal capacity, it is very important to avoid this vicinity when adding the initiator. In addition, when the polymerization conversion rate is less than 60% may cause unwanted side reactions may adversely affect the initial color and other physical properties.

In addition, since the vinyl chloride monomer is almost exhausted when the polymerization conversion rate is about 75%, the polymerization pressure starts to drop. Therefore, when it is added when it exceeds 75%, the effect of shortening the reaction time by additional addition of a water-soluble initiator does not appear.

Therefore, the present invention is characterized by further adding a water-soluble polymerization initiator in the period of 60% to 75% after the polymerization conversion rate. In particular, it is preferable to further add in the polymerization conversion period of 65 to 70%.

It is preferable that the said water-soluble polymerization initiator is a water-soluble peroxide. The addition of the oil-soluble peroxide may improve the polymerization productivity, but due to the increase of the residual initiator content in the final vinyl chloride polymer, it may lead to a decrease in the initial coloring property, in the present invention to limit only the water-soluble initiator.

The water-soluble peroxides used in the present invention are, for example, hydrogen peroxide, potassium peroxide, ammonium persulfate and the like. In view of the shortening of the double reaction time and the initial complexation, potassium peroxide is preferred.

The water-soluble initiator is generally capable of using 0.0001 to 0.02 parts by weight based on 100 parts by weight of the total charged monomer, suitably 0.001 to 0.015 parts by weight, and most preferably 0.002 to 0.01 parts by weight. When the amount of the water-soluble initiator used is less than the appropriate amount, the effect of shortening the reaction time is inadequate, and when used in excess of the appropriate amount, fine particles increase, thereby lowering the initial colorability of the resin.

The shape of stirring apparatuses, such as a stirrer and a baffle, used in this invention is not specifically limited, The stirring apparatus conventionally used for the suspension polymerization method of a vinyl chloride type monomer can be used conventionally. For example, paddles, pitched paddles, bloomers gins, pdoradoras, turbines, propellers, etc. may be used as the stirring blades or may be combined with several kinds of stirring blades. Can be used. Examples of the baffles include plate, cylinder, D, loop and finger types.

In one embodiment of the present invention, a protective colloid preparation, an oil-soluble polymerization initiator, and a hydrogen ion regulator are added to a reactor together with deionized water as a solvent, and then a vinyl chloride monomer is added in a vacuum to perform polymerization.

According to the production method of the vinyl chloride-based polymer of the present invention, deionized water, a protective colloid preparation and an oil-soluble initiator and a hydrogen ion concentration regulator are added to a reactor, and then a vinyl chloride monomer is added in a vacuum state and suspended at a normal polymerization reaction temperature. It is a method for producing a vinyl chloride polymer slurry by reaction by polymerization.

In preparing the vinyl chloride polymer, an antioxidant may be added at a time point at which the polymerization conversion rate is 83 to 87%. The antioxidant is not particularly limited as long as it is generally used in the production of vinyl chloride-based polymers, and specific examples thereof include triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxy phenyl ) Propionate], hydroquinone, p-methoxy phenol, t-butylhydroxyanisole, n-octadecyl-3- (4-hydroxy 3,5-di-t-butyl phenyl) propionate, 2,5-di-t-butyl hydroquinone, 4,4-butylidenebis (3-methyl-6-t-butyl phenol), t-butyl catechol, 4,4-thio bis (6-t- Phenol compounds such as butyl-m-cresol), tocopherol, and nojihydroguaiachinic acid, amine compounds such as N, N-diphenyl-p-phenylene diamine, and 4,4-bis (dimethyl benzyl) diphenyl amine , Sulfur compounds such as dodecyl mercaptan, 1,3-diphenyl-2-thiol and the like can be used alone or in combination of two or more thereof.

In the preparation of the vinyl chloride polymer, if necessary, additives such as a polymerization regulator, a chain transfer agent, a pH regulator, a crosslinking agent, an antistatic agent, a scale control agent, a surfactant, and the like are partially or partially divided before or after polymerization. It can be added more continuously.

In general, the polymerization degree of the vinyl chloride polymer is determined by the polymerization reaction temperature, and the polymerization degree is a factor that greatly affects the processing conditions and the physical properties of the product, so an appropriate polymerization reaction temperature should be selected. The general polymerization temperature range of the vinyl chloride polymer produced for commercial purposes is preferably 30 to 80 ° C.

The prepared vinyl chloride polymer slurry may be prepared as a final vinyl chloride polymer by removing moisture with a fluidized bed dryer under conventional reaction conditions.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

[Example]

Example  One

Of deionized water to the 1m ³ reactor having a reflux condenser, 390kg, di-2-ethylhexyl peroxydicarbonate 150g, a moisture content of 80% and also the viscosity of the 4% aqueous solution at room temperature hydrated 30cps of polyvinyl alcohol 120g, 80 g of polyvinyl alcohol having a viscosity of 5 cps at a room temperature of 40% and a 4% solution was added to the reactor in a batch, vacuum was applied, 300 kg of vinyl chloride monomer was added, and the initial reaction temperature of the polymerization was raised to 57 ^o C. The reaction was carried out while maintaining, and 6 g of potassium perperate was further added in the polymerization conversion period of 65% to 70%. When the polymerization reactor pressure reached 6.0 kg / cm ² , 60 g of triethylene glycol-bis- [3- (3-t-butyl-methyl-4-hydroxyphenyl) propionate] was added, and then unreacted monomer was added. Recovered and the polymer slurry was recovered in the polymerization reactor. The slurry thus obtained was dried in a fluidized bed dryer in a conventional manner to obtain a vinyl chloride polymer.

Example  2

In Example 1, polymerization was carried out and evaluated under the same conditions as in Example 1 except that 6 g of potassium perperate was added in the polymerization conversion rate of 60% to 65%.

Example  3

In Example 1, polymerization was carried out under the same conditions as in Example 1 except that 6 g of potassium perperate was added in the polymerization conversion period of 70% to 75%.

Example  4

The polymerization was carried out and evaluated under the same conditions as in Example 1 except that 1.5 g of potassium perperate was added in Example 1 above.

Example  5

The polymerization was carried out and evaluated under the same conditions as in Example 1 except that 45 g of potassium perperate was added in Example 1.

Example  6

In Example 1, polymerization was carried out and evaluated under the same conditions as in Example 1 except that 6 g of hydrogen peroxide was further added in place of potassium perperate.

Comparative example  One

Except for the addition of potassium perperate in Example 1 was carried out in the same manner as in Example 1.

Comparative example  2

In Example 1, 165 g of di-2-ethylhexyl peroxydicarbonate was added, and potassium perperate was not added in the same manner as in Example 1.

Comparative example  3

In Example 1, polymerization was carried out and evaluated under the same conditions as in Example 1 except that 6 g of potassium perperate was further added in the polymerization conversion rate of 50% to 60%.

Comparative example  4

In Example 1, polymerization was carried out and evaluated under the same conditions as in Example 1 except that 6 g of potassium perperate was further added in the polymerization conversion rate of 75% to 80%.

The physical properties of the vinyl chloride polymers prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

* Apparent specific gravity-measured according to ASTM D1895-89.

* Particle Distribution-Based on the particle distribution measurement method of ASTM D1705, the weight percents of the samples passed through the sieves of # 60 and # 200 were respectively determined.

* Initial colorability-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 added to 100 parts by weight of the obtained polymer, and kneaded at 150 ° C. for 5 minutes using a roll. After that, a sheet was prepared. The sheets were cut and overlapped and made into press sheets by press molding. The compressed sheet was visually observed and evaluated according to the following criteria.

(Double-circle): It is the level of coloring similar to this based on the comparative example 1, and a level which is satisfactory practically.

(Circle): Based on the comparative example 1, it is a color degree of the grade which is inferior to this slightly but there is no abnormality, and is a level which is satisfactory practically.

X: The level with which a pigmentation degree differs clearly and this color tone differs in practical use on the basis of the comparative example 1, and this.

* Fish-eye amount-100 parts by weight of vinyl chloride polymer, 45 parts by weight of DOP, 0.1 parts by weight of barium stearate, 0.2 parts by weight of tin stabilizer, and 0.1 parts by weight of carbon black using a 6-inch roll at 140 ° C. After mixing and kneading for 6 minutes, a sheet having a thickness of 0.3 mm was made and represented by the number of white transparent particles in 100 cm ² of this sheet and measured.

In the results of Examples 1 to 6 it can be seen that the polymerization reaction time is shortened, the polymerization yield is increased, and the initial colorability is excellent compared to the comparative example. By adding a water-soluble initiator after Xc (the point where the maximum calorific value appears), it effectively utilizes the reactor effective heat removal capacity and increases the conversion efficiency of the unreacted vinyl chloride monomer dissolved in the late polymerization phase. In addition to increasing the speed, the polymerization conversion efficiency of the final vinyl chloride polymer was increased to further improve the polymerization yield.

In the case of Comparative Example 1 is a conventional method for producing a vinyl chloride polymer, in the case of Comparative Example 2, the reaction time can be shortened by increasing the amount of oil-soluble polymerization initiator, but the effect of increasing the polymerization conversion efficiency is not expected, oil-soluble polymerization Increased initiator dosage resulted in poor initial colorability. In the case of Comparative Example 3, the addition time of the water-soluble initiator was too early than the polymerization conversion period of 60%, the initial color deteriorated due to unwanted side reactions, and in the case of Comparative Example 4 was added when the polymerization conversion rate exceeded the 75% period The addition of a water-soluble initiator shortens the reaction time and increases the polymerization conversion efficiency.

Although described in detail above with reference to the specific embodiments of the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and such modifications and modifications belong to the appended claims. It is also natural.

Claims (12)

A method for preparing a vinyl chloride polymer by suspending and polymerizing a vinyl chloride monomer in the presence of a protective colloid preparation and an oil-soluble polymerization initiator, wherein a water-soluble polymerization initiator is added in a period of 60% to 75% after polymerization conversion of the vinyl chloride monomer. Vinyl chloride-based polymer production method comprising the step of adding. The method of claim 1, Method for producing a vinyl chloride polymer, characterized in that the water-soluble polymerization initiator is a water-soluble peroxide. 3. The method of claim 2, And said water-soluble peroxide is at least one member selected from the group consisting of hydrogen peroxide, potassium peroxide, and ammonium persulfate. The method of claim 3, The method for producing a vinyl chloride polymer, characterized in that the water-soluble peroxide is potassium peroxide. The method of claim 1, Method for producing a vinyl chloride-based polymer, characterized in that the water-soluble polymerization initiator is added to 0.0001 ~ 0.02 parts by weight based on 100 parts by weight of the totally charged vinyl chloride monomer. The method of claim 5, Method for producing a vinyl chloride-based polymer, characterized in that the water-soluble polymerization initiator is added to 0.001 ~ 0.015 parts by weight based on 100 parts by weight of the total charged vinyl chloride monomer. The method of claim 6, Method for producing a vinyl chloride-based polymer, characterized in that the water-soluble polymerization initiator is added to 0.002 to 0.01 parts by weight based on 100 parts by weight of the totally charged vinyl chloride monomer. The method of claim 1, Method for producing a vinyl chloride-based polymer, characterized in that the addition of the water-soluble polymerization initiator in the polymerization conversion period of 65 to 70% of the vinyl chloride monomer. The method of claim 1, The protective colloid preparation is a vinyl alcohol resin having a degree of hydration of 30 to 95% by weight and a viscosity of 4% aqueous solution at 5 to 60 cps at room temperature, and a viscosity of 2% aqueous solution measured at room temperature with 5 to 40% by weight of propyl hydroxide. The vinyl chloride polymer manufacturing method, characterized in that at least one selected from the group consisting of a cellulose of 10 to 10,000 cps, and a polymer of an unsaturated organic acid. The method of claim 1, The vinyl chloride monomer is a method of producing a vinyl chloride polymer, characterized in that further comprises a vinyl monomer copolymerizable with the vinyl chloride monomer in an amount of less than 50% by weight. The method of claim 10, And the vinyl monomer is at least one member selected from the group consisting of olefin compounds, vinyl esters, unsaturated nitriles, vinyl alkyl ethers, unsaturated fatty acids and anhydrides of these fatty acids. A method for preparing a vinyl chloride polymer by suspending polymerizing a vinyl chloride monomer in the presence of a protective colloid preparation and an oil-soluble polymerization initiator, wherein the water-soluble polymerization is carried out after the maximum calorific value of the polymerization reaction and before the polymerization pressure begins to drop. Vinyl chloride-based polymer production method comprising the step of adding an initiator.