JPH01217016A - Polymerization of vinyl chloride-based monomer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention] Industrial Application Field 1 The present invention relates to an improved method for polymerizing vinyl chloride monomers. For more details, please refer to Vinyl Chloride 1lit1
A mixture consisting mainly of vinyl chloride monomers or vinyl chloride monomers and copolymerizable monomers (hereinafter, these are collectively referred to as "vinyl chloride monomer 1", and this monomer is polymerized. The present invention relates to a method for preventing the adhesion of polymer scale on the inner wall surface of a polymerization vessel and/or the surface of equipment incidental to the polymerization vessel during the polymerization of vinyl monochloride-based polymer 1).

[Juniorai Technique 1 Polymerization of a vinyl chloride monomer is usually carried out by emulsifying or suspending the vinyl chloride monomer in an aqueous medium containing an emulsifier or a dispersant in the presence of a polymerization initiator. In this polymerization process, parts are installed on the inner wall of the polymerization vessel, the stirring blades and baffles that are incidental equipment of the polymerization vessel, the walls of the reflux condenser, and the polymerization vessel. Polymer scale is deposited on the walls of various pipes that come into contact with vinyl chloride monomers (hereinafter collectively referred to as polymerization vessel inner walls, etc. 1), which reduces the polymer yield. However, in addition to reducing the cold JI capacity of the polymerization vessel, the physical properties of the product (
For example, fish eyes) are reduced, excessive labor and time are required to remove the attached scale, and the operating rate of the polymerization vessel is reduced. Furthermore, if you enter the polymerization vessel and try to remove the attached scale, you will be exposed to vinyl chloride monomer, which is a disadvantage for occupational health. Therefore, solving these problems has been a major concern for those who manufacture vinyl chloride polymers.

Conventionally, as a method of preventing polymer scale from adhering to the inner walls of a polymerization vessel, etc., a method has been proposed in which a substance with a scale-inhibiting effect is applied to the inner walls of a polymerization vessel, etc. 6 For example, (1) 7 Polar compounds such as amine compounds, quinone compounds, and aldehyde compounds, dyes, and free run compounds +1-. (2) Applying an alkali metal salt of xanthate (3) Applying three components: paint, polyamine, and dialdehyde (4) Applying two components: polyethyleneimine and aldehyde Method (5) A method of applying the three components of an alkali metal salt of xanthic acid, polyethyleneimine, and aldehyde, etc. can be mentioned.

Problem to be Solved by the Invention 1 However, the method of -1- (1) does not have a sufficient effect of preventing scale adhesion, and has one disadvantage of being short-lasting. Although the Noj method (3) has an excellent effect of preventing scale adhesion, it has the disadvantage that its sustainability is short. In addition, the method (4) above has the disadvantage that the effect of preventing scale adhesion (1) is small and its persistence is short. Furthermore, although the above method (5) has a fairly good effect on preventing scale adhesion and its sustainability, it is still not sufficient. There is a problem in that the coating film peels off in parts such as blades where the slurry flow velocity is low, resulting in a lack of durability. Furthermore, after applying the coating agent, the inner wall of the polymerization vessel is heated at high temperature to dry and solidify in order to quickly cause the polyethyleneimine-aldehyde crosslinking reaction, but at this time, since the aldehyde has a low boiling point, it is not only lost due to evaporation, but also There are problems such as the formation of non-uniform areas in the film layer. .

Step 1 for Solving Problem E As a result of intensive studies to solve the problems of the prior art, the present inventors applied an alkali metal salt of xanthic acid using polyethyleneimine and dialdehydes. When the polyethyleneimine and dialdehydes are fixed together, the crosslinking reaction between the polyethyleneimine and the dialdehyde proceeds more quickly, forming a uniform coating layer, and the strength of the coating film is greatly improved. The present invention was completed based on the discovery that the sustainability of the product was significantly improved.4 In other words, the gist of the present invention is to use vinyl chloride monomers or vinyl chloride monomers as a main component and monomers copolymerizable therewith. In polymerizing the mixture of (C) in an aqueous medium, an alkaline xanthate is present on the inner wall of the caulking polymerization vessel and/or on the surface of the equipment attached to the polymerization vessel.

The present invention will be explained in more detail below.

Examples of the alkali metal salts of xanthate used in the present invention include sodium ethylxanthate, potassium enalxanthate, sodium butylxanthate, potassium butylxanthate, sodium amylxanthate, potassium amylxanthate, and the like. Can be mentioned.

Further, the borie ethyleneimine can be obtained by polymerizing ethyleneimine, and the dialdehyde used is dialdehyde or its precursor. Examples of dialdehydes include glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, 7-nopine dialdehyde, maleic dialdehyde, 7-talaldehyde, in-7-talaldehyde, and tele7.
Examples include taraldehyde. Precursors of dialdehyde include flukoxy compounds such as 1, 1, :(,:(tetramethoxib O-pan, 1111313te)laethoxif-ropan, succinaldehyde sulfite, etc.) which react with dialdehyde in an aqueous solution. What is generated is used.

In the present invention, the method of fixing and coating xanthate alkaline salts using polyethyleneimine and dialdehydes is to apply solutions of these components individually or in combination to surfaces such as the inner wall of the polymerization vessel. Implemented. When dialdehydes are mixed with polyethyleneimine, some dialdehydes quickly undergo a crosslinking reaction and become water-insoluble. Therefore, when used in combination, it is preferable to add Schiff (/aldehyde) immediately before application. .in particular,
After applying an aqueous solution of xanthokenic acid alkali () group salt and polyethyleneimine, apply 17F7 solution containing aldehydes (
A method of spraying a water 7s solution, a 1iso'P# medium solution, or a mixed solution thereof (two-step coating), ]-A method of spraying and spraying a mixture of 3 and 51 in a spray nozzle immediately before coating. A preferred embodiment is a method such as one-stage coating.

Furthermore, it is desirable to use a metal salt in combination in order to further increase the strength of the fixed film of double polyethyleneimine and aldehydes and to further improve the scale adhesion prevention effect. Metal salts include alkali metals such as sodium and potassium, alkaline earth metals such as magnesium, calcium, and barium, zinc group metals such as zinc, aluminum group metals, tin group metals such as titanium and tin, and iron such as iron and nickel. Silicates, carbonates, and bicarbonates of metals selected from chromium group metals such as chromium and molybdenum, manganese group metals such as manganese, prepared metals such as copper and silver, and platinum group metals such as platinum. , phosphates, nitrates, balates, acetates, hydroxides, oxides, halides, and the like.

The usage amounts of the three ingredients listed in are not particularly limited, but
In order to obtain good coating performance, the ratio of xanthate alkali metal salt/polyethyleneimine/dialdehyde is preferably within the range of 10/10 to 5300/10 to 300 in heavy electric ratio. From the viewpoint of influence on coating workability such as viscosity, it is preferable to use the concentration of each component or three components in the coating liquid in the range of 0.5' to 30 ffilt%.

The coating liquid is applied to the inner wall of the polymerization vessel by a commonly used application means such as spraying. In the coating film, polyethyleneimine and dialdehyde undergo a crosslinking reaction to become water-insoluble, and the alkali metal xantokenate is firmly adhered to the inner wall surface of the polymerization vessel. Although this crosslinking reaction can be carried out by standing at room temperature, it is more efficient to accelerate the reaction by heating.

Specifically, the inner wall of the polymerization vessel may be heated to 50...7100°C by passing hot water or steam through it to make it glossy, and then the coating solution may be applied and allowed to dry and harden for about 120 minutes. After coating, it may be heated to a temperature above one above to dry and solidify.

1- The amount of the three components to be applied is the total amount after drying, that is, the amount of the three components is usually 0.
1) l/II'' or less, preferably to 0.01.

The range is 10t (/bite 2).The application amount is (1,01g
/ 2 or less, the generation of scale cannot be sufficiently suppressed. Moreover, if it exceeds IOH/m2, no increase in the prevention effect can be expected, and on the contrary, the enclosing force against the wall surface of the coated material tends to weaken.

In the method of the present invention, the polymerization of vinyl-based IF@ bodies is as follows:
All commonly known polymerization vessels 7j are adopted, and the dispersant, emulsifier, polymerization initiator, etc. used do not need to be special, and commonly used dispersants, emulsifiers, polymerization initiators, etc. are used. For example, dispersants and emulsifiers include protective colloidal agents such as partially saponified polyvinyl acetate, acrylic acid copolymers, maleic anhydride copolymers, cellulose derivatives, gelatin, starch, etc. or 7-ion surfactants such as natural polymer compounds, esters of higher fatty acids and polyhydric alcohols, polyoxyethylene derivatives, metal salts of higher fatty acids, and alkali salts of higher alcohol sulfates. Agents are used.

Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide, lauroyl peroxide, nooctylberoxycarponate, and acetylcyclohexylsulfonyl peroxide, 7zo compounds such as azobisisobutyminitrile and dimethylvaleronitrile nato, potassium persulfate,
Persulfates such as ammonium persulfate are used.

The vinyl chloride monomers produced by the method of the present invention include vinyl chloride monomers themselves, vinyl chloride monomers mainly composed of vinyl chloride monomers, and monomers copolymerizable with the vinyl chloride monomers. Examples of the copolymerizable monomers include olefins such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl stearate, and vinyl ethers such as ethyl vinyl ether and heptyl vinyl ether. , unsaturated carboxylic acid derivatives such as acrylic acid esters, maleic acid or 7-malic acid esters and anhydrides, maleimide and its N-substituted derivatives, aromatic vinyl compounds such as styrene, unsaturated nitrile compounds such as 7-crylonitrile. Any conventionally known monomers capable of co-merging with vinyl chloride can be used.

[Effect of the invention 1] According to the method of the present invention, there is no or insignificant scale adhesion to the inner wall of the polymerization vessel during the polymerization reaction, so the occurrence of fish eyes etc. in the final processed product is completely eliminated. This improves the quality of the product, and since the number of cleaning times for the inside walls of the polymerization vessel is significantly reduced, operation can be continued without extensive cleaning, productivity is improved, and costs are also reduced. Very advantageous results are obtained.

In addition, it not only makes it easier to manage crops such as cooling, but also
It also becomes possible to use a reflux condenser as a new cooling means.

Furthermore, the method of the present invention can be applied when using a low-boiling point polymerization initiator that has traditionally been particularly prone to scale build-up, such as butyl peroxybivalate or diisopropyl peroxynocarbonate, or when using a special polymerization initiator for quality improvement. Even when an auxiliary agent such as sorbitan ester is added, a stable scale adhesion prevention effect is exhibited.

1 Example 1 The present invention will be explained in more detail by examples below, but the present invention is not limited by the following examples unless it exceeds the gist thereof.

Example 1 Potassium ethylxanthate,
Polyethyleneimine (manufactured by Nippon Shokubai Kagaku Co., Ltd., Epomin P-
1000), spray a mixed solution of glutaraldehyde and dry at 100°C to form a film on the inner wall surface. Using this polymerization vessel, 140 kg of pure water and 25 g of vinyl chloride 1 (10 kg, partially saponified polyvinyl acetate 60, nota tertiary pneumatic peroxybeverley) were charged and polymerized at approximately 50°C until a predetermined polymerization rate was reached. I did it. After polymerization, there was no scale adhering to the inner wall of the polymerization vessel or stirring blade.

Further polymerization was repeated, and no scale was observed even after 70 polymerizations.

Comparative Example 1 When polyethyleneimine (Epomin P-1000) was reacted with glutaraldehyde using the same polymerization vessel as in Example 1, a considerably thick scale layer was formed on the entire surface from the first time [1].

Note that the slurry after the reaction in Example 1 and Comparative Example 1 had a value of 4 or less in both cases.

Example 2 A multi-tubular 171-flow cooler with a heat exchange area of 1 x 2 was attached to a pressure-resistant stainless steel polymerization vessel with an internal volume of 2000 +, and 800 kg of pure water and 720 kg of vinyl chloride were added to it. , 400 g of partially saponified polyvinyl acetate, and 150 g of noocnal peroxycarbonate were charged, and polymerization was carried out at about 58° C. until a predetermined polymerization rate was reached.

Prior to this polymerization, potassium ethylxanthate, polyethyleneimine (manufactured by Nippon Shokubai Kagaku Co., Ltd., Epomin P-1000), glutaraldehyde, and water were added to the stirring blades, inside the reflux condenser, inside the reactor connecting conduit, and on the inner wall of the polymerization vessel. 2 each,
When ff# liquid mixed in proportions of 4, 1 and 100 parts was sprayed and treated at 100°C to form one film,
There was no scale adhesion to the inside of the reflux-cooled JJI vessel, the communication conduit, the inner wall of the polymerization vessel, or the stirring blade.

Note that after the reaction was completed, the slurry pH was 3.2.

Comparative Example 2 The same method as in Example 1 was carried out except that 77taldehyde was used instead of glutaraldehyde. The generation of χ1 can now be seen in areas where there is originally a lot of adhesion, such as the tsumugi part.

Patent Applicant Tamabishi Kasei Vinyl Co., Ltd. Awayo Rihito Ben I'l! -1. Hasegawa - (1 idiot)

Claims (1)

[Claims] When polymerizing a vinyl chloride monomer or a mixture of vinyl chloride monomers and copolymerizable monomers in an aqueous medium, xanthogens are added to the inner wall of the polymerization vessel and/or the surface of the polymerization vessel accessory equipment in advance. A method for polymerizing vinyl chloride monomers, which comprises coating an acid alkali metal salt, polyethyleneimine and dialdehyde.