KR830000854B1 - Manufacturing method of vinyl dispersion resin - Google Patents

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Description

[Name of invention]

Manufacturing method of vinyl dispersion resin

Detailed description of the invention

The present invention relates to a method for producing a vinyl dispersion resin using an electrolytic solution in emulsion polymerization.

It is known to plasticize or change vinyl resins from hard, keratinous and cured to soft and plasticlable conditions by adding plasticizers such as dioctylphthalate at high temperatures. These vinyl polymers or resins are called dispersion resins or paste resins, and are usually produced by emulsion polymerization. In some cases, suspension polymerization may be used, but emulsion polymerization is suitable.

When the vinyl dispersion resin is mixed with a plasticizer, this is called plastisol. Due to the fluidity of the plastisols, it can be molded into a variety of useful products. For example, plastisols can be used to make shaped articles, films, and coatings. Thus, the vinyl dispersion resin can be easily and uniformly mixed with a plasticizer to produce a low viscosity plastisol capable of producing a product such as a film having a stable, uniform and appropriate size particle size and good transparency.

It is not possible to obtain a suitable lattice using conventional emulsion polymerization methods, since this lattice is usually too fine or too large with particles of different sizes. Various proposals have been made to solve these drawbacks in the past, but ultimately failed. For example, the use of various different emulsifiers and catalysts has been proposed. There has also been proposed a method of changing the polymerization conditions. However, in most cases, the latex produced is too much coagulant, or the coagulant particles are partially present, and the coagulation is severely solidified, thereby lowering the yield. It is also desired that the lifetime of these gratings be long. These gratings are suitably changed in viscosity during storage and have good heat resistance.

U.S. Patent No. 4,076,920 dated February 8, 1978, describes a method for producing a vinyl dispersion resin, which describes a method for producing a composite having a unique property for end use. However, this patent also needs to dry-spray the latex or polymer emulsion resulting from the aggregation of aggregated particles, as in other conventional methods, and it is necessary to grind them to a size that can be used for plastisols. By pulverizing the polymer to a size usable for the plastisols and changing the size and shape of the mill, the prepared plastisols have a higher viscosity than their solid components. In addition, excessive grinding is required, causing overheating to melt the polymer. In contrast to “pearl” or suspension polymerization, if the polymer particles are large enough to filter, the vinyl dispersion cannot be recovered from the emulsion by filtration and is dried in a tray, because the particles are filtered out of the filter. It is difficult to formulate into soft plastisols that pass through and form small cakes during tray drying, forming solid cakes that can be processed most industrially even after grinding. The particles of the polymer used in the plastisols are suitably spherical in order to have the smallest particle surface possible. In addition, the dispersion of spherical particles has a minimum flow viscosity for treatment with shaped articles, coatings, and the like (see US Pat. No. 3,179,646, dated 20 May 196).

Another problem in the production of vinyl dispersion resins is the formation of unnecessary aggregates on the inner surface of the reactor. The deposition or reinforcement of the polymer on this reactor surface not only hinders thermal conduction but also lowers productivity and adversely affects the overall body quality by producing finer particles than the adverse effects produced in viscosity. This polymer reinforcement must be removed. Firstly it is suitable to prevent or eliminate polymer reinforcement.

The inventors have conducted the emulsion polymerization of vinyl dispersion resins in the presence of an electrolyte, such as “fugitive” ammonium carbonate (NH ₄ ) ₂ CO ₃ ), which evaporates during drying. It can be dried into a spherical aggregate of polymer particles that can be separated into individual spherical polymer particles by simply rubbing or pulverizing. In the case of tray drying in addition to the electrolytic solution in the method of the present invention, the polymerization of the vinyl monomer is carried out at a temperature of 48 ° C. or lower, and the presence of a long-chain alcohol having 14 to 24 carbon atoms and an ammonium salt of a high-quality fatty acid having 8 to 20 carbon atoms. It is carried out in an aqueous alkali solution using a free group to produce a polymerization initiator under the above, wherein the ratio of alcohol to emulsifier is the same or equal to or greater than 1.0, and the reactive components are mixed thoroughly and suitably mixed prior to polymerization. . When using the process of the present invention the polymer reinforcement in the reactor reactor is reduced and multistage polymerization is carried out in the reactor without opening the reactor to substantially reduce the amount of unreacted monomer.

In the present invention, the vinyl dispersion resin means a polymer and a copolymer of vinyl and vinylidene halides such as vinyl chloride, vinylidene chloride and the like.

The vinyl halide and vinylidene halide may be copolymerized with one or more vinylidene monomers having one or more terminal CH ₂ = C groups. Examples of such vinylidene monomers include esters of acrylic acid such as α, β-olefin unsaturated carboxylic acids such as acrylic acid, methacrylic acid and α-cyanoacrylic acid, such as methyl acrylate, ethyl acrylate, butyl acrylate and octyl acryl. Ester of methacrylic acid, such as the rate and cyanoethyl acrylate, such as methyl methacrylate and butyl methacrylate, nitriles, acrylonitrile and methacrylonitrile, acrylamide, for example methyl acrylamide, N- Methyl ether acrylamide, N-butoxyl methacrylamide and the like, vinyl ethers such as ethyl vinyl ether chloroethyl vinyl, ether and the like, vinyl ketones, styrene and styrene derivatives such as α-methyl styrene, vinyl toluene, chloro styrene, Vinylnaphthalene, allyl and vinyl chloroacetate, vinylacetate, vinylpyridine, methylvinylketone and others skilled in the art There can be a vinylidene monomers of the types known. The present invention is particularly used in the production of vinyl dispersion resins or pastes prepared by polymerizing one or more vinylidene monomers copolymerizable with about 80% by weight, based on the weight of vinyl chloride or vinylidene chloride alone or monomer mixtures. The most suitable vinyl dispersion resin is polyvinyl chloride (PVC), for the sake of simplicity the present invention describes it briefly, which is described for illustrative purposes only and not in a limiting sense.

An important aspect of the present invention is to provide a method for producing a vinyl dispersion resin, in which a polymer latex or polymer emulsion can be formed, and then the polymer particles can be spherically dried into spherical aggregates by simply drying on a tray. . This is to eliminate cumbersome spray drying and grinding processes that often degrade the polymer material. The concept of the present invention for tray drying a polymer emulsion is to use an electrolyte in a polymerization method. As the electrolyte solution which can be used in the present invention, ammonium carbonate ((NH ₄ ) ₂ CO ₃ ), calcium chloride (CaCl ₂ ), potassium carbonate (CaCO ₃ ) ammonium phosphate, bicarbonate, sodium carbonate, sodium bicarbonate, sodium phosphate, and the like can be used. The amount of the electrolyte solution suitable for use in the present invention is about 0.05 to 6.0% based on the weight of the monomer to be polymerized, and it is suitable to use an amount of 0.1 to 2.0% by weight.

The breakable aggregates produced in the process of the invention are clearly advantageous and improved over conventional methods for recovering vinyl dispersions or paste resins from water for use in plastic sol, for example spray drying followed by grinding. Way. The breakable aggregates of the present process can be easily treated in the postpolymerization step of recovering the polymer or resin. The breakable aggregate is easily formed, and each spherical particle of the vinyl dispersion resin can be easily formed by pulverizing or simply rubbing the aggregate to the particle size required for the paste resin. Typically, each spherical particle of the polymer will have a particle size or particle diameter between 0.1 and about 10.0 microns. For the present industrial use of plastisols it is suitable that the polymer particles have 0.2 to 2.0 microns.

In the emulsion polymerization method, the use of electrolyte solution has found other advantages besides being able to improve the quality of the product by using tray drying.

For example, the use of electrolytes in the polymerization process shortens the time to complete the polymerization as the ratio of monomers to polymers increases, which in turn increases production per unit time, reducing the production cost of vinyl dispersion resins when using this method. do.

Another feature of the present invention is to reduce the amount of polymer deposit on the inner surface of the reactor. On the other hand, it is not known exactly why such a decrease in deposition occurs, but it is thought to be due in part to the use of the electrolyte in this method and also due to the reaction rate and the low reaction temperature, because the polymer deposition amount is allowed to react at high temperatures for a long time. Because it increases. In some cases, polymer deposition problems can be greatly improved by using the present invention. In addition, by using this method, vinyl dispersion resins and plastisol properties such as thermal stability, water resistance, fluidity, etc. are not adversely affected, and these properties are actually improved.

It is necessary to use a suitable emulsifier when producing a vinyl dispersion resin using the emulsion dispersion method. For example, various fatty acid derivatives and salts thereof can be used as well as C ₁₂ -C ₂₀ alkyl or aryl hydrocarbons or various mixtures thereof. However, in the present invention, it is suitable to use an ammonium salt of long-chain saturated fatty acid as an emulsifier in order to obtain suitable water resistance and thermal stability in a film made from a plastisol of a vinyl dispersion resin. Saturated fatty acids may be natural or synthetic fatty acids, which must have from 8 to 20 carbon atoms. As examples of such acids, lauric acid, myristic acid, palmitic acid, marganic acid, stearic acid, tallow, palm oil can be used. Ammonium chloride is used in an amount of about 0.5 to 4.0% based on the amount of monomer to be polymerized. It is also possible to use ammonium salt mixtures of fatty acids as emulsifiers.

Ammonium salts of fatty acids can be prepared by mixing fatty acids with ammonium hydroxide, separating the salts, and then adding them to a polymerization medium or a preliminary polymerization mixture in a conventional manner. However, it is suitable to prepare ammonium salts, that is, fatty acids and ammonium hydride are added separately to the polymerization mixture or polymerization medium and reacted here to prepare the salts. The reaction solution should be kept alkaline using excess ammonium hydroxide in an amount greater than necessary to react with the fatty acid.

In addition to the ammonium of long-chain fatty acid emulsifiers, it is suitable to use a mixed long-chain saturated alcohol, which contains 14 to 24 carbon atoms. As examples of such alcohols, it is suitable to use tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, tricosanol and tetracosanol. Mixtures of alcohols can also be used, and in most cases it is suitable to use alcohol mixtures, for example alcohols having 14 carbon atoms and alcohols having 18 carbon atoms. In addition, alcohols with a low carbon content can be mixed with long chain alcohols and used, for example, as a mixture with dodecanol and octadecanol. When using alcohol, the ratio of alcohol to ammonium salt of fatty acid can be used as 1.0. However, when this ratio is used above 1.0, optimal results are obtained.

As mentioned above, the reaction medium should be maintained at an alkaline, suitably high pH. This method can be performed at a pH between about 7.0 and about 12.0. However, it is suitable to carry out the reaction at a pH between about 8.0 and about 10.5. If the pH is too high, too much ammonium hydroxide is used. If the pH is too low, for example, below 7.0, the polymer deposition in the reactor increases and the amount of aggregation increases. The amount of NH ₄ OH needed to properly adjust the pH will depend in part on the particular emulsifier used in the reaction mixture. Of course, to adjust the pH of the reaction mixture, alkali chemicals such as NaOH and KOH can be used. The choice of specific alkaline chemicals depends on the components in the reaction solution.

The process of the present invention using an electrolyte solution in a reaction mixture and tray drying the product is carried out in the presence of a compound capable of initiating a polymerization reaction. It is suitable to use free radical generators commonly used to polymerize olefin unsaturated monomers. Useful initiators or catalysts include, for example, various peroxide compounds such as lauryl peroxide, isopropyl peroxydicarabutate, benzoyl peroxide, t-butylhydroperoxide, t-butylperoxybivalate, cumene hydroperoxide, t- Butyl diperphthalate, cumene hydroperoxide, t-butyl diperphthalate, pelargonil peroxide, 1-hydroxycyclohexyl hydroperoxide, etc. Can be. In addition, water-soluble hydrogen peroxide compounds such as hydrogen peroxide, persulfates such as potassium persulfate, ammonium persulfate and the like can be used as useful initiators. The amount of the initiator generally used is about 0.01 to 0.5% by weight based on the weight of the monomer to be polymerized, and about 0.02 to 0.1% by weight is suitable.

In the process of the invention, the initiator is completely charged at the start of the polymerization or is gradually added to the reactor during the polymerization. However, it is suitable to charge the initiator premixed with the initiator mixed with other components of the reaction mixture at the start of the polymerization. This is advantageous to homogenize the premix prior to introduction into the reactor. When the initiator is added to the monomer premix and then stirred thoroughly by high-speed stirring, or when homogenizing the premix, for example when alcohol is used in the reaction mixture. For example, it is necessary to keep it below the reaction minimum temperature of the specific initiator using the temperature. The minimum reaction temperature of a particular initiator can be readily determined by those skilled in the art, and this initiator is commonly supplied by the polymerization initiator or catalyst manufacturer. The temperature is adjusted to the temperature at which the reaction occurs before the monomer premix is introduced into the reactor.

In the emulsion polymerization method of the present invention, the reaction temperature is important because the intrinsic viscosity (IV) of the resulting vinyl dispersion resin directly affects the reaction temperature. This means that the lower the intrinsic viscosity (IV), the higher the temperature. The end use of the vinyl dispersion resin thus formed determines the reaction temperature. For example, when producing vinyl dispersions for use in coatings or cast flexible films, lower temperatures may be applied to obtain high grade IV desirable for various coatings or film-forming methods. When the vinyl dispersion resin of the present invention is particularly used, a polymerization temperature between about 30 ° and 70 ° C. is suitable. However, it is suitable to use a temperature between about 30 ° C and 55 ° C.

Other particles that must be considered with regard to the temperature of the reaction are polymer deposits in the reactor. In general, as the reaction temperature increases, the amount of polymer deposited in the reactor increases. However, the polymer deposit is not crusty and can be removed by rinsing with water or by watering from the bottom, and it is necessary to open the reactor when a suitable spray nozzle is installed in the reactor. On the other hand, the deposition amount of this polymer can be controlled and reduced by the presence of electrolyte in the reaction solution. By mixing with the electrolyte, the walls of the reactor are kept cool during the initial stages of the reaction, in particular where most of the deposits are formed. The adjustment of the reaction temperature can be accomplished using conventional means, for example a jacketed reactor which circulates cold water or other liquids in the jacket. The synergistic effect is obtained by using the electrolyte and the cooling reaction medium in the early stages of the reaction cycle, because the amount of polymer deposition is reduced. Repetitive cycles are used to increase the process efficiency and to reduce the manufacturing cost of vinyl dispersion resins for light levels without cleaning the surface of the reactor between charges or cycles.

After the completion of the polymerization reaction, the vinyl dispersion resin can be separated into powder form, that is, separated spherical aggregate particles. This filters the latex from the polymerization reactor to recover the breakable aggregate of polymer and trays the filtered latex at a temperature between about 230 ° C. and 100 ° C. Under normal pressure, the electrolyte flows out during the reaction. The drying temperature may use a temperature lower or higher than the above temperature limit, which temperature depends on whether the drying step is carried out under vacuum or under constant pressure. Tray drying time depends on the particular polymer being dried. However, tray drying continues until the polymer content in the polymer is below about 0.1% by weight. Of course, this time will depend on the temperature used. What is important is that the polymer is not heated for a long time at high temperatures because long-term heating adversely affects the quality of the polymer, for example discoloration. After tray drying, the spherical aggregate of polymer particles is simply crushed or rubbed to crush each spherical particle to recover the dry polymer or resin in powder form. The powdered resin is then made into plastisol. Other drying forms or methods may be used, for example rotary dryers, air jet dryers, fluidized bed dryers, unless spray drying is used. However, tray drying is suitable.

The plastisol is a spherical polymer particle type separated using a conventional heating stirring method and can be made into the vinyl dispersion resin of the present invention by uniformly mixing 100 parts by weight of the vinyl injection resin and about 30 to 100 parts by weight of one or more plasticizers. . Useful plasticizers include alkyl and alcoholcyalkyl esters of dicarboxylic acids or esters of polyhydric alcohols and monobasic acids. Examples of plasticizers include dibutyl phthalate, dioctyl phthalate, dibutyl sebacate, dinonyl phthalate, di (2-ethylhexyl) phthalate, di (2-ethylhexyl) adipate, dilauryl phthalate, dimethyl tetrachlorophthalate, di Butyl phthalyl butyl glycolate, glyceryl stearate, etc. can be used. Suitable plasticizers are liquid diesters of aliphatic alcohols having 4-20 carbon atoms and basic carboxylic acids having 6-14 carbon atoms.

The plastisols prepared from the vinyl dispersion resins of the present invention have the desired yields and have little or no expansion. Yield refers to resistance to flowability and is usually measured numerically by measuring viscosity using a standard method known in the art. Normally such a value is obtained by calculation from a viscosity measurement using a Brookfield model RVF viscometer by ASTM method D1824-61T. Yield is obtained by aging at regular intervals in the initial stage of preparation to measure the viscosity of the plastisol at variable rpm. Viscosity is measured in centipoise (CPS) at 23 ° C. In a particular example, the viscosity measurement is performed at 2 rpm and 20 rpm, indicated by V ₂ and V ₂₀ , respectively.

Hereinafter, the present invention will be described in detail by way of examples, in which all parts and percentages are by weight unless otherwise indicated.

Example 1

In this example, a series of tests were conducted to understand various aspects of the present invention. The method and reaction conditions to be used are shown in the following table.

In this table, all numbers are parts by weight based on the weight of the total composition.

TABLE 1

In Test Examples 2 and 3 above, when alcohol is used, the monomer premix tank or vessel should be emptied. The premix tank is initially filled with water and then the electrolyte is added under stirring followed by the emulsifier and alcohol mixture. Next, a catalyst is added and finally, vinyl chloride is added. The temperature in the premix tank was controlled at about 25 ° C. by cooling jackel. The mixture was stirred for about 15 minutes. Thereafter, the mixture or the preliminary monomer mixture is passed through a mantin Ganlin two-stage crusher at 25 ° C. and passed through a polymerization reactor previously emptied. The pressure is 600 psig in the first stage of the mill and 700 psig in the second stage. The contents of the reactor were heated to a reaction temperature of 45 ° C. and then maintained at this temperature for the entire reaction until the desired conversion was obtained. The reactor was then cooled, ventilated and dried by removing polyvinylchloride (PVC) latex or slurry. The appropriate data is shown in Table II below.

In Test Examples 1, 4 and 5, the components were placed in a polymerization reactor and mixed. The emulsifier was also fed to the reactor during the reaction. In Test Examples 1 and 4, the seed was placed in a reactor, and vinyl chloride was prepolymerized thereto to obtain a larger particle size. In Test Example 5, the temperature of the reaction mixture was increased until 40 to 60% conversion was obtained. After holding at 占 폚, the temperature was lowered to 35 占 폚 and held at this temperature until the reaction was complete. Thereafter, in each case the reactor was cooled and vented and the PVC latex or slurry was removed and dried.

In order to measure the Brookfeed viscosity, the plastisol was made of resin or PVC using the following ingredients.

100 parts of PVC dioctyl phthalate 40 parts

Dioctyl adipate 30 parts Epoxidized soybean oil 3 parts

Barium-cadmium-zinc phosphate part 2

Data on viscosity are shown in Table II below.

TABLE 2

As can be seen from the above results, the use of an electrolyte solution uses a tray drying method to have a good dry cake degradability and an excellent plastisol phase.

Example II

In this example, a series of tests were conducted to change the concentration of the electrolyte solution. The same polymerization method as in Example 1 was used, except that homogenization was not used. Plastisols were also made as in Example 1. The results are shown in the following table.

TABLE III

In the table above, “bubble cream” under slurry viscosity is the ideal condition for slurry or latex. It can be seen from Table III that the dry cake has good or extremely good fracture properties. As a result, it is evident to use tray drying followed by electrolytic solution. Thus, when the electrolyte solution is used in the polymerization medium from the above embodiment, the emulsion polymerization lattice can be filtered and dried on the tray, thereby improving the properties of the produced vinyl dispersion paper. More importantly, the spray drying and coarse grinding steps, which adversely affect the polymer quality, can be removed by the method of the present invention. In addition, this method yields a larger amount of dispersion resin per unit time, and the resin has improved properties and reduces the amount of polymer deposit on the inner surface of the polymerization reactor. All of these particles are due to the production of vinyl dispersion resins at low cost. Many other advantages of the invention will be apparent to those skilled in the art.

Claims (1)

About 0.01 to 0.5% by weight of free radical formation catalyst per 100 parts by weight of monomers or monomers to be polymerized, reaction aqueous solution, monomers to be polymerized or monomer, about 0.05 to 6.0% by weight electrolyte based on monomer or monomer weight, emulsifier for polymerization, A monomer premix is prepared containing at least one long chain saturated alcohol having 14 to 24 carbon atoms, wherein the ratio of alcohol to emulsifier is at least 1.0, and homogenizing at temperatures below the reactivity of the catalyst using the premix. The premix is passed through a reaction zone, and emulsion homopolymerized in the reaction zone at a temperature of about 30 ° C. to 70 ° C. to form individual spherical crushable aggregates of spherical polymer particles and react the pH in the reaction zone. Until the end is maintained in the range of 7.0 to about 12.0, the polymer fluid is separated from the reaction zone and filtered Recovering the crushable aggregates of the polymer, tray drying the polymers and the crushable aggregates of the polymer, while removing the electrolyte solution and simply crushing the crushable aggregates to form polymer spherical particles of various types, depositing the polymer in the reaction zone. Vinyl dispersion, characterized in that the amount is reduced to produce polymers and copolymers thereof of vinyl and vinylidene halides having, alone or together, one or more vinylidene monomers in at least one terminal CH ₂ = C <group Method for producing a resin.