JPS5978210A - Nonaqueous polymerization of vinyl chloride - Google Patents

Abstract

PURPOSE:To reduce formation and deposition of polymer scale, by applying a specified water-soluble dye and/or highly saponified polyvinyl alcohol to the surface of a polymerization vessel, in (co)polymerizing a vinyl chloride monomer in a nonaqueous system. CONSTITUTION:Preparations are made for a water-soluble dye having at least one -SO3Na or -SO3H group, having at least one benzene, naphthalene, or anthraquinone ring, and further having a phenolic -OH and/or an -NH3 group (e.g., Congo Red or Evans' Blue) and/or highly saponified polyvinyl alcohol of a degree of saponification >=95mol% and a viscosity (in 4% aqueous solution) of 20-40cP (20 deg.C). Then, this water-soluble dye and/or highly saponfied polyvinyl alcohol are applied to the wall of a polymerization vessel with which the polymerization reaction product in the system is in contact to carry out nonaqueous (co)polymerization of a vinyl chloride monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a modified bulk polymerization method of vinyl chloride monomer or a single monomer mixture copolymerizable with vinyl chloride monomer.

It is well known that during bulk polymerization of vinyl-based monomers such as cyclized vinyl, polymer scale is often deposited on polymerization reaction equipment such as the inner wall of the reactor and the stirring canopy. These scales usually need to be removed by cleaning after completion of polymerization, which requires a great deal of labor and time.

In addition, the formation of polymer scale causes a significant decrease in heat transfer efficiency, making it necessary to adjust the amount of feed, resulting in a decrease in productivity. Furthermore, it is unavoidable that exfoliated and pulverized polymer scales are mixed into the product polymer, and the fish-eye properties, thermal stability, etc. of the product processed from this at 113°C are affected.
There are many problems such as deterioration of characteristics.

In the past, attempts have been made to reduce scale formation in the bulk polymerization of vinyl chloride and the like by improving the shape of the stirrer, but these have not necessarily yielded sufficient results. Concerns about vinyl chloride, etc. Shu 1: "Many examples of scale inhibitors have been presented in terms of legality, but some patent applications regarding bulk polymerization methods (for example, Japanese Patent Application Laid-Open No.
37309. 1973-37306. 1976-109
985° Dosho 5l-112892). However, the effects of the methods described in these publications are not necessarily sufficient, and in some cases, the polymerization is inhibited so much that the polymerization hardly progresses and, therefore, scale cannot be formed.

The present inventors have conducted extensive research to solve these problems.
As a result of Tt, vinyl monomers such as vinyl chloride (VO
In non-aqueous polymerization methods such as liquid or gas phase bowl polymerization (M), polymerization is carried out by applying a specific compound in advance to the inner wall of the reaction vessel, the stirring blade, and the parts where reactants such as monomers come into contact. It has been found that the formation and adhesion of polymer scale during the course of 1 reaction is greatly reduced. Therefore, in this method, especially in bulk prepolymerization, continuous use is possible by simply washing with vinyl chloride monomer (hereinafter abbreviated as VOM) after discharging the slurry. In addition, it is possible to easily remove the scraps that are sometimes formed. Therefore, productivity is greatly improved and product quality does not deteriorate.

The gist of the present invention is that when a mixture of a vinyl chloride monomer or a monomer copolymerizable with vinyl chloride and a vinyl chloride compound is combined in a liquid phase or gas phase, the inner wall of a reactor, a stirring blade, etc. (1) is a water-soluble dye and has (a) in its molecular structure in advance at the part where the reactants such as monomers come into contact with.
(b) Has 11 benzene or naphthalene rings or anthraquinone IVJ; (c) Phenolic -〇H group and/or -NH
One of the dyes satisfying the above requirements (11) (and/or (2) has a degree of saponification of 95 mol% or more, and the viscosity of a 4% aqueous solution thereof at 20°C is in the range of 20 to 43 cps). It is characterized by adhering a certain highly saponified polyvinyl alcohol.

Next, the present invention will be explained in detail.

As a result of various studies regarding the water-soluble dyes used in the present invention, l) Those that inhibit or inhibit polymerization include:
Phthalein dyes, thiazine dyes, triphenylmethane dyes, azine dyes, etc. mainly exhibit this effect.

Also, in azo dyes, -803Na group (from -EIO, H
Groups) show this effect probably because they dissolve in VOM.

2) Those which do not exhibit a polymerization inhibiting effect but are not effective in preventing scale, mainly have -8O3Na groups (or -8o3H groups) and are insoluble in VOM.

3) There are many azo dyes that hardly interfere with polymerization and are effective in preventing scale, but not all azo dyes are effective, and those that are effective have the following structure in the molecule. .

(In) Having a -So, Na group (b) Having a benzene ring or naphthalene ring via an azo group (c) Having a 10H group on the benzene ring or naphthalene ring, -N
It is preferable to have H, a group or both polar groups, but not to have polar groups such as a -000H group and a -0ONH- group.

However, even if these conditions are met, there are differences in the scale prevention effect depending on the number of substituent positions.

Examples of effective products as shown in Table 1 are Di
roct Deep Black, Br1llia
nt Orange.

Orange 1. Bordeaux S, O
ongo Red.

Kvans Blue, Bordeaux R,T
h1azin Red.

For example, Diamine GreθnB. Particularly effective is DiamjneGreen B, Th1a.
zinRecl, Oong.

ROd, EV a n S B 1 u e r
B Ord e au X R, etc.

Father, anthraquinone dye with -8O3Na group and -〇H
There are some bases that are effective in preventing scale. However, although anthraquinone dyes have a school prevention effect, they may mix with the generated PVC and cause coloring, and although there is little adhesion scale, they have some difficulty in removability. However, the effect is slightly lower.

As a valid example, Th1azin Red 5al
t8 etc.

In addition, various studies have been conducted on polymeric substances that are effective as an inder when applying the dye, and also have the effect of preventing scale by themselves.

1) Many of the substances that are effective in aqueous polymerization methods such as suspension polymerization of oil-soluble polymers are V-based.
Dissolves in OM and prevents or inhibits polymerization. Also, although it does not inhibit polymerization, it is not effective in preventing scale. Furthermore, although they are somewhat effective in preventing scale, water-soluble polymers and water-soluble cellulose derivatives are less effective because they have difficulty in releasability or are heated at temperatures higher than 1°C.

Regarding water-soluble synthetic polymers, for example, polyethyleneimine, ethylene oxide adducts of higher alcohols, etc. exhibit polymerization inhibiting or inhibiting effects.

Polyacrylic acid, polyacrylamide, polyethylene glycol, etc. show almost no interference with polymerization, but
Not effective in preventing scale.

(b) Polyvinyl alcohol (PVA) does not exhibit any undercarriage interference effects. However, partially saponified PVA is not effective in preventing scale.

Highly saponified PVA with saponification +n' of 95 to 100 mol %, with polymerization I8- in the range of about 1400 to 2000, in the range (4
% aqueous solution with a viscosity at 20° C. of 20 to 45 cps) was found to be effective in preventing scale. Those with lower molecular weight or higher molecular weight than this 87 old Ill are also not effective.

Preferred Ql is one having a saponification degree of 98 to 100 mol% and a viscosity of 27±5 cps (4% aqueous solution at 20°C).

Furthermore, various studies were conducted regarding the combination of PVA and water-soluble + "4' dyes. Regarding water-soluble dyes with the above structure, that is, azo dyes, (a) -N through the benzene ring or naphthalene LM 'l
=N- bond, (b) -8O3Na group (or -1903H group), 09 phenolic -〇H group, or -NH,
4% aqueous solution viscosity of 206C.2 with at least one kind of anthraquinone dye and the aforementioned saponified M'95 to 100 mol%.
When highly saponified PVA in the range of 0 to 43 cps is mixed and used, scale adhesion is reduced due to the mutual effect of these, and a stable and strong coating film is created, eliminating the contamination of the produced 1F polymer. Continuous use is also possible.

Such an effect is due to the above-mentioned water-soluble +'1. This effect is not exhibited when a dye is mixed with a water-soluble polymer other than PVA.

No effect is expected if the amount of PVA applied is less than 7 m2 of α6. Also, applying 10v/m2 or more at one time is
It is difficult because the viscosity Ji is high. The preferred range is O, S~
It is 597m2. Also, the water-soluble dye is 0.05-5?
/ m' range is good; below 0.052/m2, no mutual effect of scale prevention is exhibited, and 5 f/m
It is not preferable to apply more than 2 because no improvement in the effect can be expected and it will be disadvantageous in terms of cost reduction. Preferably 01-115f
/m2 is good.

Mix and apply in advance at any ratio within the above range,
It may be applied to the surface of the polymerization equipment by means such as immersion or fogging. In addition, the water-soluble dye is not limited to yuzu, but a mixture of several kinds may be used.

Also, depending on the purpose, water-soluble inhibitors such as hydroquinone, resorcinol,
It is even more effective if phenol or the like is mixed in advance and applied.

When applying 4S'i, PVA, and mixtures thereof, using a solvent or water as a medium improves the adhesion to the vessel wall and provides a suitable coated surface.

The organic solvent used here is, for example, methanol.

Ethanol, acetone, etc. In addition, when applying these to the vessel wall, it is preferable to perform a polishing process such as polishing in advance to make the coating uniform. Father, after applying these bath liquids to the vessel wall by means such as coating, dipping, or spraying, once it is dry to the touch or more, it can be used. When applying PVA, drying at 100°C or higher increases water resistance. Furthermore, if some scale is generated after polymerization, it is necessary to improve the adhesion and water resistance of the coating film in order to prevent the coating from separating by φ1 when removing it by washing with water. In this case the above! Among the water-soluble dyes that meet the requirements of Improves water resistance. Furthermore, if the pH of the mixture is made acidic to prevent gelation, a film having a three-dimensional structure can be formed in the same manner as in the case where the mixture is coated, dried, and then treated with alkali.

In order to impart water resistance to a PvA film, drying at a high temperature of 100°C or higher is usually required, which is not practical. It is practical because it can impart water resistance by drying at a similar temperature.

As described above, the method of the present invention is intended for liquid phase bulk polymerization or gas phase bulk polymerization of a mixture of VOM or a monomer copolymerizable therewith with vcM. Other copolymerizable monomers include vinyl fluoride, vinyl halides such as vinyl bromide, ethylene,
propylene.

lZ olefins like n-butene, vinyl acetate, globimene 6 &''vinyllaurin rf?vinyl, vinyl esters like stearin C+F vinyl, acrylic 1T4
f171 Methacrylic 7tB11 and unsaturated phase acids such as itaconic acid and esters of histo, vinyl esters such as methyl vinyl ether, ethyl vinyl ether, maleic acid, fumaric acid, maleic anhydride or their derivatives, stainless steel & 4, derivatives thereof, Vinylidene chloride.

Examples include vinylidene fluoride.

The polymerization initiator used in the present invention is oil-soluble P1.
- radical initiators are preferred. These include lauroyl peroxide, benzoyl peroxide, alumbar oxide, peroxine esters of organic acids such as tert-butyl peroxide biparate, dioxycarbonates such as diisopropyl peroxydicarbonate, and azobisdimethylvalerol. Examples include azo compounds such as nitrile, acetylcyclohexylsulfonyl peroxide, and the like. These initiators are used in an amount of 0005 to 6% by weight based on the monomer.

The liquid phase bulk polymerization reactor and gas phase bulk polymerization reactor used in the present invention are not particularly limited. Polymer solvents are not used for purposes such as droplet FM and heat transfer medium. However, non-solvents such as hexane may be used.

In addition to the polymerization vessel, the polymerization equipment to which the coating of the present invention is applied includes condensers, valves, conduits, pumps, measuring instrument detectors, 4% L stirring blades, jammer plates, etc. as accessories of the polymerization reactor. These are generally made of stainless steel or glass-lined steel.

Qisodan, state? As the I+-combiner, a polymerization tank equipped with a stirrer or a gas fluidized bed reactor may be used.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the examples alone.

Example 1 The following equipment was used as a polymerization apparatus.

The first stage is a vertical autoclave made of 304 stainless steel equipped with a turbine and stirring blades;
The 9th autoclave is a vertical autoclave made of stainless steel with a content of A1, equipped with an anchor-shaped stirring blade and one stage of strip-shaped ailerons.

Kv on the inner wall of each autoclave, stirring signal, shift, etc.
ans Blue 1: Saponification degree 98.5-99%.

4% PVA2 with viscosity 27±2.5 cps (20°C)
0.0 aqueous solution 0.2t 7m” (first stage),
4? / Apply it so that it becomes the second (second stage), 5o
It was dried at 0c for 1 hour. After the apparatus was replaced with hema, 17 kg of VOM was charged into the first stage polymerization vessel, stirred at 700 rpm, and heated to an internal temperature of 55°C by passing water through the jacket.

After reaching a constant temperature, acetylcyclohexylsulfonyl peroxide (hereinafter abbreviated as AC8P) 20% solution 5.6
me was charged together with V CM j kg and polymerized for 2 hours. Next, the offshore slurry from the first stage was transferred to a second stage commercial can that had been deaerated in advance, and the first stage fabric can was spray cleaned with 5 kg of VOM, and these were also charged into the second stage. 25kq for song
V'C! Add M to the 2nd stage mountain, finger at 200 rpm,
The mixture was stirred and the jacket was heated to reach an internal temperature of 56°C. Wash 10 ml of 50% diisopropyl peroxydicarbonate (hereinafter abbreviated as PP) with VCM 2kq in regular crystal, combine with 1-iIT at 6 o'clock, collect unreacted VOM, and add 1.5 ml of diisopropyl peroxydicarbonate at 60°C. Vacuum suction was carried out for a period of time to remove internal substances and take out the product.

The 11 ratio was 80%.

The first stage polymerization reactor has a small amount (5
gr, ) was easily peeled off with only attached scale. The scale attached to the second stage polymerization can is 200 gr.
: This also peeled off easily after washing with water.

Further, 100 gr of the product was spread on white paper and visually inspected in small quantities, and it was found that there were no more than 5 colored polymer grains.

Comparative Example 1 Polymerization was carried out using the same equipment and the same formulation as in Example 1, without applying any scale inhibitor.

In the first stage can, scale adhered to the entire inner wall of the can, the stirring blade, the shaft, etc., and the peelability was extremely poor, and the amount of scale peeled off with a souffle bar was about 350 gr. Scale was also stuck to the entire surface of the can wall, the stirrer, the shaft, etc. of the can in the second stage, and the total weight of the can was approximately 1200 gt when removed with a souffle bar.

In addition, here (71), prepare the tetrahydrofuran solution and stir both cans 4'4' and vortex (40℃) to dissolve the scale.
After removal, washing with acetone and water is necessary.

Example Example 1i (1! Using the same equipment and the same formulation as Example 1, Congo Red 1:i%l specific P was used as a scale inhibitor.
0.1r/m2゜1.4 of VA14 aqueous solution
? /m2, 70℃, 11), 'j=
The same was dried and combined.

The scale in the first market can was easily removed by washing with water at 10 gr, and the scale inhibitor remained as it was. The scale in the second stage could be easily removed by washing with water at 250 gr, and the scale inhibitor remained as it was.

Example 3 Using the device of Example 1, remove the rectangular aileron of the second stage can,
A spray nozzle with a hole diameter of 1.5 mm was attached to the center of the can as an anchor-shaped blade.

Congo Red 1:Specific PVA as mentioned above 10 parts of an acidic (pH 3) aqueous solution of sulfuric acid, respectively. /
m2゜29/m2 and 'IIC, respectively, in a polymerization machine, and when it dries to some extent, ammonia water and Na20
After contacting the 03 liquid with the painted surface, the temperature was 70°C and 1! Samurai-go was dry.

The first stage polymerization was carried out using the same formulation as in Example 1, and the polymerization slurry was used in the second stage at 100! The liquid was transferred to a can, and the liquid from which the first stage can was spray-cleaned with 5 to 9 VOM was also transferred.

Next, stir the 1001 can at 120 rpm and
Unreacted VOM was collected at 0°C2, internal pressure 3.8 kg/2G, and when the internal temperature reached 52°C, Jacquera l-? The temperature was increased to 60° C., the internal pressure was adjusted to 1 OkqArL2G, and 4.0 ml of 50% I'PP was injected together with VOM from a press-in spray nozzle. VOM
was introduced by spraying, and unreacted VOM was collected and reused. The amount of polymer produced was 9 in 42.

The amount of scale in the first stage polymerization vessel was 6 gr, which was adhered only to the gas-liquid interface. This was easily peeled off by washing with water. The amount of adhesion in the second stage polymerization vessel was 20 gr, which was mostly electrostatic adhesion. This was also easily peeled off by washing with water, and there was no blemish on the coated product. In addition, the number of colored substances mixed in the produced polymer is 1 to 2 cases/
It was 100gt. In this case, j1 state% (coalescence gas phase 7
1f was repeated 10 times, but the scale ffHt-1 to 2
This was a variation in the error range of gr culm degree.

Comparative example 2 Same side 14 as actual sister example 3. Polymerization was carried out under the same conditions, without applying a scale inhibitor.

1''44144 The first stage was 1280 gr, and it was difficult to remove it by washing with water.The second stage was 500 gr, and most of it was electrostatically deposited and could be easily removed by washing with water.

Comparative Example 6 A small NF made of stainless steel with an anchor type blade and grade 11
Using a container, after vacuum degassing, add V CM 550 gr, stir at 250 rpm, and heat AC13P0 at a constant temperature of 55°C.
, 50 m7! The mixture was charged with VCMS [1gr] from a mixing vessel and kept at 55°C for a short time of 2 hours. After the polymerization was completed, unreacted VCM was gradually collected and powdered. The polymerization rate was 15%. The scale was fixed, and when scraped off with a stainless steel spatula, the scale was 18V (20% of the produced polymer) and could not be completely cleaned.

Example 4. Comparative Example 4 Using the same apparatus as in Comparative Example 3, each of the special dyes shown in the following table was tested. l, [The applied bone is 0.2r/m”.

After drying at 70°C for 1 hour, it was subjected to polymerization. Further, polymerization was carried out in the same manner as in Comparative Example 3. Conclusion! P is shown in Table 1.

The judgments in the table were based on the following criteria.

◎: Scale is less than 1% based on the polymer ○:
Less than 1-2%△:
Less than 2 to 4%×: Scaling/Recurrence to military compound 4 to less than 10% xx: More than 10%, the peelability of scale is poor at ℃＼ and the applied material is applied once. The items that have disappeared are indicated by adding an X to the above display (eg, ■, A).

Table 1 (Azo Dyes (Anthraquinone Dyes) (Other Water-Soluble Dyes λ) Example 5. Comparative Example 5 The cylindrical molecules shown in Table 2 were tested using the same polymerization method as in Comparative Example 3.

The coating amount was 297 m2, and it was dried at 70° C. for 1 hour and subjected to polymerization. The results are shown in the same table. Note that the determination is the same as in Example 4. The table also shows the test results for the combined use of dyes and polymeric substances.

Table 2 (Oil-soluble polymer substances) (Water-soluble polymer) (Polyvinyl alcohol)

Claims (1)

[Claims] A method of polymerizing a vinyl chloride monomer or a monomer copolymerizable therewith with a vinyl chloride monomer in a non-aqueous system such as 5 liquid phase or bulk polymerization, (2) one or more of benzene ring, naphthalene ring, anthraquinone ring, (3) phenolic -〇H group and/or -NH8 group, and/or The degree of saponification is 95 mol% or more, and the viscosity of a 4% aqueous solution is 20 to 43 cpθ (20
℃) is present on the surface of the polymerization equipment that is in contact with the 1-polymerization reactant in the polymerization system.