KR100269655B1 - Anti-fouling agent for scal prevention in pvc reaction - Google Patents

Abstract

PURPOSE: A scale inhibitor for manufacturing vinyl chloride resins is provided to improve adhesiveness of chloroethylene resin polymers against a reactant wall surface, and to prevent scale generation. CONSTITUTION: The composition of a scale inhibitor for vinyl chloride resin polymers is comprised of a scale inhibitor, additives and ion exchange water (or distilled water). As for the scale inhibitor, alizarin, formaldehyde, 2-furaldehyde or polyalizarin condensate containing the aldehydes is used. As for the additive, a dispersant selected from a group of polyvinylalcohol, polyvinylpyrrolidone and polyacrylic acid is used. The polyalizarine condensate is obtained by condensing alizarin only, or alizarine, alpha-naphthol, beta-naphthol, or the mixture of the same with formaldehyde, 2-furaldehyde or aldehydes from the mixture. Also, the scale inhibitor is used by weight of 1-50% of the composition.

Description

Scale inhibitor composition for polymerization of vinyl chloride resin

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scale inhibitor composition for polymerizing a vinyl chloride resin, and more particularly, to a vinyl chloride resin containing, as a main component, a condensate of alizarin and aldehydes or a condensate of β-naphthol and 2-furaldehyde. The present invention relates to a scale inhibitor composition that inhibits generation of scale generated on the reactor wall in a polymerization reaction.

Vinyl chloride resin is one of the five general-purpose resins. It is inexpensive, transparent and rigid. It can be processed with various additives by using additives and other additives. It is used in various ways.

The vinyl chloride resin may be prepared by suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization, or the like.

In the suspension polymerization, vinyl chloride monomer, which is a raw material of vinyl chloride resin, is added to the reactor together with a group, polyvinyl alcohol or methyl cellulose is added as a suspending agent, and an organic peroxide is added as a reaction initiator. When all the reactors are added and heated while stirring, when the inside of the reactor reaches a certain temperature, the organic peroxide is decomposed to generate radicals, and the radicals polymerize the vinyl chloride monomer to form a vinyl chloride resin. Since this reaction is exothermic, the heat of reaction is continuously removed by passing cooling water through a jacket attached to the outer wall of the reactor. At this time, the vinyl chloride monomer in the reactor is made of a vinyl chloride resin having a particle size of about 150㎛ by polyvinyl alcohol as a suspending agent.

The raw material of the emulsion polymerization is not different from the suspension polymerization, but the difference is that the emulsifier is added instead of the suspending agent to make particles having a size of 1 ~ 10㎛. In this way, a manufacturing method made by adding an emulsifier with a suspending agent is specifically referred to as 'micro suspension polymerization'. As another polymerization method of emulsion polymerization, a method using a seed is used. The seed is added to improve flowability by making two types of particles, large and small. However, the basic principle of polymerization and the side materials added are the same as emulsion polymerization.

In the polymerization, the polymerization is carried out by using only vinyl chloride monomer and initiator without polymerization and suspending agent. In the prepolymerization, the seed is made through prepolymerization, and then the seed and vinyl chloride monomer and initiator are added to the polymerization. Recovery of unreacted monomers is a process that allows the product to be produced without a drying process.

Solution polymerization is not included in the present patent, so the manufacturing method is omitted.

A common problem that occurs when producing a vinyl chloride resin using the above manufacturing method is the scale generated on the wall surface of the reactor and the stirrer.

Since the scale generated inside the reactor adversely affects the quality of the vinyl chloride resin, it is removed with high pressure washing water at every polymerization. Even if the high pressure washing water is used, the scale is continuously generated and the operator enters the reactor directly and scales with manpower. To suffer the inconvenience of removing the safety problems, as well as the direct cause of the decrease in production, environmental pollution will also be difficult to produce, such as deepening. Therefore, vinyl chloride resin manufacturers have long researched to develop a technology for suppressing the scale generated on the inner wall of the reactor.

The main patents on the scale prevention technology are as follows.

U.S. Patent No. 3,669,946 utilizes a dye called Acid Green 25, U.S. Patent No. 4,080,173 is made by condensing resorcinol, U.S. Patent No. 4,320,215 is condensed pyrogerol, U.S. Patent No. 5,229,076 and No. 5,298,578 used polyaniline condensed with aniline, and European Patent No. 52,421, used polynaphthol condensed with α-naphthol aldehyde.

However, the prior art exemplified above has a problem in that the long-term storage stability is problematic because the persistence of the anti-scale effect is degraded or easily oxidized.

Thus, the inventors of the present invention have completed the present invention by using alizarin, which is mainly used as a dye intermediate, as a scale inhibitor.

Accordingly, an object of the present invention is to provide an anti-scaling agent composition of a new composition which is used in a general polymerization reaction for producing a vinyl chloride resin and improves adhesion to the reactor wall and allows the anti-scaling effect to last for a long time.

The present invention provides a scale inhibitor composition for producing a vinyl chloride resin comprising a scale inhibitor, other additives, and ion-exchanged water, wherein the scale inhibitor contains polyalizarin condensate or α-naphthol and 2-furaldehyde condensate. do.

Referring to the present invention in more detail as follows.

In the present invention, the poly alizarin condensate used as the anti-scaling agent is a condensation of alizarin and aldehydes, which easily removes the charged charges generated on the reactor wall, thereby adhering to the reactor wall in the vinyl chloride polymerization process. Improve the anti-scaling effect.

Various compounds may be used as the aldehydes for the alizarin condensation according to the present invention, and among them, formaldehyde or 2-furaldehyde is particularly preferable.

In addition, the present invention uses a condensate obtained by condensation of α-naphthol, β-naphthol, or a mixture thereof, which has been conventionally used as an anti-scaling agent together with alizarin, in the condensation of alizarin and aldehydes, as an anti-scaling agent. It also includes. In this case, it is preferable to include α-naphthol, β-naphthol or a mixture thereof within 10 to 40% by weight relative to the alizarin content in terms of increasing the active ingredient concentration.

In the present invention, β-naphthol and 2-furaldehyde condensate contained as another scale inhibitor can be used as a scale inhibitor by selecting and using a specific aldehyde. That is, according to the contents disclosed in European Patent No. 52,421, it is impossible to use β-naphthol and formaldehyde condensate as a scale preventing agent, but it is impossible to use it as a scale inhibitor. This allows it to be produced in the liquid state and used as an antiscaling agent.

In addition, the anti-scaling agent composition according to the present invention may contain a dispersing agent for evenly dispersing the anti-scaling agent together with all the additives normally contained. Such dispersing agents include polyvinyl alcohol, polyvinylpyrrolidone and polyacrylic acid. Use the selected one.

When explaining the manufacturing process to the scale inhibitor composition for producing another vinyl chloride resin in the present invention in more detail as follows.

Add 3 to 15 parts by weight of sodium hydroxide, preferably 5 to 10 parts by weight of water, and stir well until completely dissolved. Then, 10 to 50 parts by weight of alizarin, preferably 15 to 40 parts by weight, and add temperature to 80 parts by weight. Raise to ℃. At this time, α-naphthol or β-naphthol may be added together with the alizarin. When the aldehydes are slowly added at 5 to 15 parts by weight, preferably 8 to 12 parts by weight at 80 ° C., a dark brown liquid is formed. 10-30 parts by weight of the dispersant, preferably 15-20 parts by weight, is stirred in the liquid to prepare a dark brown liquid composition of black color for the purpose of the present invention.

After coating the inner wall of the reactor evenly with the scale inhibitor composition of the present invention prepared by the above production method, the polymerization reaction is carried out based on the general vinyl chloride resin production method, such as emulsion polymerization, suspension polymerization, block polymerization. When plotting the reactor wall using the scale inhibitor composition of the present invention, the concentration is 1 to 50% by weight, preferably 1 to 10% by weight. If the concentration of the anti-scaling agent composition is too dilute, the anti-scaling effect of the present invention cannot be sufficiently obtained, and if the concentration is too high, the viscosity increases and there is a problem in coating the inner surface of the reactor.

The application amount of the anti-scale agent composition to the reactor is 50 to 300 g / 1 m 2 (application area) based on the 5% solution.

As a result, it was confirmed that the scale generation rate was significantly reduced in the reaction using the reactor to which the scale inhibitor composition of the present invention is applied.

Such a present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Example 1

100 parts by weight of ion-exchanged water was added to the reactor, 4.8 parts by weight of sodium hydroxide was added, and alizarin, α-naphthol or β-naphthol was added as a scale inhibitor, and the temperature was raised to 75 ° C. and stirred for one hour. 37% formaldehyde was added to the reaction solution and reacted until there was no exothermic phenomenon. The reaction solution was filtered through a filter to add 20 parts by weight of polyvinyl alcohol to obtain a scale inhibitor composition. The composition of the prepared composition is shown in Table 1 below.

Prior to the polymerization reaction for the production of vinyl chloride resin, the reactor wall surface was coated with 100 g / 1m 2 (coating area) with the above-described scale inhibitor composition. After heating the reactor wall and evaporating the water completely, 125 parts by weight of water, 100 parts by weight of vinyl chloride monomer, 0.07 parts by weight of polyvinyl alcohol (72 to 90% of hydration) and 0.04 parts by weight of organic peroxide as an initiator were added. After stirring for 30 minutes, the suspension was polymerized at 58 ℃ for 8 hours. After the reaction was completed, the unreacted vinyl chloride monomer was recovered, the reactor manhole was opened, the inside was inspected, and polymerization was continued in the same manner to measure the number of polymerizations that could be continuously polymerized until a scale was formed. Is shown in Table 1 below.

TABLE 1

According to the results of Table 1, β-naphthol is hard to react with formaldehyde, and thus cannot be used as a scale inhibitor, and a blue condensate obtained by condensing a-naphthol and formaldehyde condenses alizarin with formaldehyde. As can be seen from the polyalizarin condensate, the continuous process is possible, but it is easily oxidized in the air and discolored to brown when heated, so it can be seen that there is a problem in storage stability.

Example 2

100 parts by weight of ion-exchanged water was added to the reactor, 4.8 parts by weight of sodium hydroxide was added, and alizarin, α-naphthol and / or β-naphthol were added as a scale inhibitor, and the temperature was raised to 75 ° C. and stirred for one hour. 37% formaldehyde or 37% 2-puraldehyde was added to the reaction solution and reacted until there was no exothermic phenomenon. The reaction solution was filtered through a filter to add 20 parts by weight of polyvinyl alcohol to obtain a scale inhibitor composition. The properties of the prepared composition are shown in Table 2 below.

Prior to the polymerization reaction for the production of vinyl chloride resin, the reactor wall surface was coated with 100 g / 1m 2 (coating area) with the above-described scale inhibitor composition. Then, suspension polymerization was carried out in the same manner as in Example 1. The polymerization was continued to measure the number of polymerizations that could be continuously polymerized until the scale was formed. The results are shown in Table 2 below.

TABLE 2

As shown in Table 2, as shown in Example 2, in addition to formaldehyde, for example, other aldehydes, for example, 2-puraldehyde may be used to prepare a scale inhibitor. Particularly noteworthy is the condensation of β-naphthol with formaldehyde, which results in hard masses, making it impossible to use as antiscalants [European Patent No. 52,421; See Table 1 of the present invention], when condensed with 2-puraldehyde to produce a dark green liquid can be used as a scale inhibitor. Therefore, the selection of specific aldehydes is also important in the present invention.

In addition, the effect did not change even if Alizarin and α-naphthol were mixed.

Example 3

100 parts by weight of ion-exchanged water was added to the reactor, 4.8 parts by weight of sodium hydroxide was added, 38 parts by weight of alizarin was added, and the temperature was raised to 75 ° C. and stirred for one hour. 37% 2-puraldehyde was added to the reaction solution until the reaction was not exothermic. The reaction solution was filtered through a filter, and 20 parts by weight of polyvinyl alcohol, polyvinylpyrrolidone or polyacrylic acid were added thereto. An antiscaling agent composition was obtained. The properties of the prepared composition are shown in Table 3 below.

Prior to the polymerization reaction for the production of vinyl chloride resin, the reactor wall surface was coated with 100 g / 1m 2 (coating area) with the above-described scale inhibitor composition. Then, suspension polymerization was carried out in the same manner as in Example 1. The polymerization was continued to measure the number of polymerizations that could be continuously polymerized until the scale was formed. The results are shown in Table 3 below.

TABLE 3

According to the result of Table 3, it was found that when the polyvinyl alcohol, polyvinylpyrrolidone or polyacrylic acid was included as the dispersant, the dispersion of the anti-scale agent was easier.

As described above, alizarin, which is mainly used as a dye intermediate, is used as an anti-scaling agent. As a result, it is possible to improve adhesion to the reactor wall and suppress scale formation in general polymerization reaction for producing vinyl chloride resin. Has an effect.

Claims (3)

In the scale inhibitor composition for producing a vinyl chloride resin consisting of a scale inhibitor and other additives and ion-exchanged water, As the anti-scaling agent, a poly alizarin condensate containing an aldehyde selected from alizarin and formaldehyde, 2-furaldehyde or a mixture thereof is contained, and as the additive, a dispersant selected from polyvinyl alcohol, polyvinylpyrrolidone and polyacrylic acid A scale inhibitor composition for producing a vinyl chloride resin, characterized in that it contains. The method of claim 1, wherein the poly alizarin condensate is obtained by condensing alizarin alone or alizarin and α-naphthol, β-naphthol or a mixture thereof with an aldehyde selected from formaldehyde, 2-furaldehyde or a mixture thereof. The scale inhibitor composition for vinyl chloride resin manufacture. The scale inhibitor composition for producing a vinyl chloride resin according to claim 1, wherein the concentration of the scale inhibitor composition is 1 to 50% by weight.