KR101168401B1 - Method of manufacturing high molecule latex resin powder and the powder manufactured by using the method - Google Patents

Abstract

The present invention relates to a method for producing a polymer latex resin powder, comprising: (a) a flocculation step of supplying a polymer latex and a flocculant to a flocculation tank to form a slurry of the polymer latex; (b) steam injection step of injecting steam to the slurry formed; And (c) relates to a method for producing a polymer latex resin powder comprising the step of transferring the slurry sprayed steam to a aging tank, according to the present invention excellent polymer latex resin powder with low water content and low content of fine particles It can be provided, excellent drying efficiency, can provide a method for producing a polymer latex resin powder having an excellent particle size distribution.

Latex, flocculation, steam, spraying, aging, moisture content, drying efficiency

Description

METHOD OF MANUFACTURING HIGH MOLECULE LATEX RESIN POWDER AND THE POWDER MANUFACTURED BY USING THE METHOD}

The present invention relates to a method for producing a polymer latex resin powder, and more particularly, by adding a steam spraying step with multiple nozzles to a conventional agglomeration process method, it can exhibit a low water content to increase the efficiency of the drying process, the particle size of the powder It relates to a method for producing a polymer latex resin powder to excellent distribution.

A method of continuously preparing a polymer latex prepared by a general emulsion polymerization process using polymer powder is as follows. Firstly, when an aqueous solution of a flocculant such as an inorganic salt or an acid is added to the polymer latex, the electrostatic stabilization of the polymer latex by the emulsifier is broken, and the polymer particles in the latex are agglomerated with each other. This phenomenon is called coagulation. However, since the slurry formed through the aggregation forms a kind of multi-particle assemblage that does not form a physical bond, the slurry easily breaks up due to external shear force in this state. This can happen. Therefore, as a next step of flocculation, the aging process is performed to increase the strength of the slurry through physical bonding. This is done at high temperature, and the interpenetration between the chains causes the slurry to form one particle with some strength.

However, most of the processes mentioned above have the disadvantage that the agglomeration process is very fast due to the use of excess coagulant, so that the process of entanglement between the polymer latex particles becomes quite disordered, resulting in an irregular shape and a considerably wider particle size distribution. It causes a lot of problems. In fact, when a large amount of powder having a diameter of 450 μm is produced, a problem occurs in transport and storage, and when a large amount of fine powder having a size of 70 μm or less occurs, dehydration and drying capacity decrease, and due to scattering of fine powder during packaging It causes loss of resin, problem of powder transfer in process, environmental pollution by dust generation, and deterioration of working environment of workers.

As a method for improving this problem, U.S. Patent No. 4,897,462 discloses a slow aggregation method below a critical aggregation concentration, but does not overcome the high viscosity region of the initial state generally occurring during the slow aggregation, it is not a continuous batch batch There is a limitation that can be applied only to the process, and the spherical powder water content of spherical agglomerates is high, so the dehydration effect is deteriorated. There is a problem that ultimately the apparent weight of the powder can be lowered.

In addition, in the case of EP 0,611,788, a slow flocculation is performed by applying a continuous flocculation process, but the slurry solids concentration is operated in a low state to overcome the high viscosity of the initial state and to obtain a uniform particle size distribution. However, when the slurry solids concentration is low, in spite of the advantage of having a uniform particle size distribution, the energy cost required for producing the product is excessively consumed, and there is a problem such as generating a large amount of waste water.

The present invention has been made to solve the above problems, an object of the present invention is to provide a method for producing a latex resin powder having a low moisture content and excellent drying efficiency compared to the conventional process method.

Another object of the present invention is to provide a method for producing a latex resin powder having a low content of microparticles, excellent drying efficiency and excellent particle size distribution.

Another object of the present invention is to provide a latex resin powder produced by the above method.

The present invention is to achieve the above object, (a) a coagulation step of supplying a polymer latex and a flocculant to a flocculation tank to form a slurry of the polymer latex; (b) steam injection step of injecting steam to the slurry formed; And (c) it provides a method for producing a polymer latex resin powder comprising the step of aging by transporting the steam-injected slurry to a aging tank.

In addition, the steam spraying step is characterized in that the steam is injected directly to the slurry using a multi-steam steam nozzle during the transfer of the aggregated slurry to the aging tank.

In addition, the pressure of the injected steam is characterized in that 2 to 15 kgf / cm ² .

In addition, the flocculant is characterized in that hydrochloric acid, sulfuric acid, phosphoric acid, calcium chloride, magnesium sulfate or a mixture thereof.

In addition, the agglomeration step is characterized in that the temperature of 60 ~ 80 ℃.

In addition, the temperature of the aging step is characterized in that 70 ~ 90 ℃.

In addition, after the aging step (d) characterized in that it further comprises a dehydration step of separating the mother liquid from the aged slurry.

In addition, the (a) flocculation step is characterized in that performed by one or more flocculation tank.

In addition, the (c) aging step is characterized in that performed by one or more aging tanks.

The present invention also provides a polymer latex resin powder prepared using the above production method.

According to the present invention, not only the polymer latex resin powder having a low water content and excellent particle size distribution can be provided as compared to the conventional agglomeration process method, but the powder can enhance the efficiency of the drying process.

The present invention (a) agglomeration step of supplying a polymer latex and a flocculant to a flocculation tank to form a slurry of the polymer latex; (b) steam injection step of injecting steam to the slurry formed; And (c) it provides a method for producing a polymer latex resin powder comprising the step of aging by transporting the steam-injected slurry to a aging tank.

Hereinafter, the present invention will be described in detail.

 (a) polymer latex flocculation step

This step is to supply a polymer latex, flocculant, water to the flocculation tank to form a slurry.

The polymer latex is a graft copolymer prepared by grafting 10 to 50% of a hard polymer to 50 to 90% of a rubber polymer and an emulsion polymerization.

The rubber polymer is mainly a diene monomer such as butadiene, isoprene, isoprene, and chloroprene, and butyl acrylate and octyl acrylate having an alkyl group having 4 to 10 carbon atoms. It is composed of an alkyl acrylate (alkyl esters of acrylic acid) monomers such as (octyl acrylate), the monomers may be used alone or in combination of two or more.

The rubber polymer is a compound copolymerizable with the diene-based and alkyl esters of acrylic acid-based monomers, and aromatic vinyls such as styrene and α-methylstyrene. Alkyl methacrylate (alkyl esters of methacrylic acid) monomers, such as monomers, methyl methacrylate, ethyl methacrylate (ethyl methacrylate) monomers, methyl acrylate (butyl acrylate) And alkyl esters of acrylic acid having 1 to 8 carbon atoms such as ethyl acrylate or vinyl cyanide such as acrylonitrile and methacrylonitrile. It may further comprise a (vinyl cyanide) -based monomer, the monomers may be used alone or in combination of two or more.

The hard polymer is a monomer constituting the branch of the graft copolymer, aromatic vinyls monomers such as styrene and α-methylstyrene, and methyl methacrylate. , Alkyl methacrylate (alkyl esters of methacrylic acid) monomers having 1 to 6 carbon atoms, such as ethyl methacrylate, butyl methacrylate, butyl methacrylate, methyl acrylate, Alkyl acrylate monomers having 1 to 6 carbon atoms, such as ethyl acrylate and butyl acrylate, acrylonitrile and methacrylonitrile Vinyl cyanide monomers such as c), or vinyl halide monomers such as vinyl chloride and vinyl bromide Etc. can be used individually or in mixture of 2 or more types.

The flocculant of this invention can be used individually or in mixture of 2 or more types of water-soluble inorganic acids, such as hydrochloric acid, sulfuric acid, and phosphoric acid, or inorganic salts, such as calcium chloride and magnesium sulfate.

The flocculant can adjust the amount of use by the critical aggregation concentration of the flocculant according to the polymer latex properties.

The polymer latex, the flocculant and the water are supplied to the lower part of the flocculation tank, and the slurry is transferred to the top of the secondary flocculation tank or the top of the aging tank by the overflow method at the top of the flocculation tank. In this way, the raw material is injected from the lower part of the coagulation tank and discharged to the upper portion, thereby preventing a short pass of the slurry, that is, non-uniform residence in the coagulation tank, and immediately discharging as compared with the conventional upper and upper discharge. Since the case is greatly reduced, there is an advantage that the residence time is evenly distributed.

The coagulation tank step may be composed of one or more coagulation tanks, and may be represented as a primary coagulation tank, a secondary coagulation tank, and the like.

The slurry which is completely aggregated in the secondary flocculation tank is transferred to another flocculation tank or aging tank by the overflow method. The temperature conditions of the secondary coagulation bath vary depending on the characteristics of the latex, and in general, it is preferable to increase the temperature in the range of 5 to 10 ° C based on the primary coagulation bath. In addition, the residence time of the secondary flocculation tank is preferably in the range of about 1 to 3 times the residence time of the primary flocculation tank, and the flocculant introduced into the secondary flocculation tank is preferably added until the remaining unaggregated polymer latex disappears. . In the case of the stirrer, it is preferable to use a pitched paddle type which is advantageous for vertical stirring in order to prevent the short pass by the overflow method.

When the coagulation tank is formed of two or more, the conditions of the coagulation tanks connected to the secondary coagulation tank are the same as those of the secondary coagulation tank.

When the coagulation tank is composed of two or more coagulation tanks, the steam spraying step described below may be performed at least once between the coagulation tanks.

(b) steam spraying step

This step is a step of injecting steam to the slurry particles produced in the coagulation tank, it characterized in that the direct contact with the steam in a larger area through the multi-jet nozzle.

That is, the steam injection step should be performed to inject steam to a large surface area of the aggregated slurry. Steam may be a gas containing water vapor that is commonly used.

The method of spraying steam to a large surface area of the aggregated slurry is not limited, but various methods can be used. However, the spraying of steam directly to the slurry using a multi-steam steam nozzle during the transfer of the aggregated slurry to the aging tank is performed. It is preferable in terms of cost.

The pressure of the steam injected is 2 or together 15kgf / cm ² are preferred, the amount of the steam increases when 2kgf / cm ² is less than, which causes too if undesirable lowers the total solids content of the slurry, excess of 15kgf / cm ² High pressures are undesirable due to process safety concerns.

In the preparation of the latex resin powder including the steam spraying step according to the present invention, in the conventional process, in order to lower the water content of the resin powder, the temperature of the flocculation tank or the aging tank had to be warmed to 85 ° C. and 95 ° C. or higher. Since there is no need for such heating conditions by the steam spraying step, there is an advantage in terms of cost of the resin powder production process.

(c) aging stage

This step is to strengthen the hardness of the slurry particles prepared in step (b).

The aging tank step may be composed of one or more aging tank, it can be expressed as a primary aging tank, secondary aging tank and the like.

The aging tank is provided with a baffle in the aging tank in order to induce smooth up and down stirring, it is preferable to use a pitched paddle as a stirrer.

Slurry particles prepared and stabilized in the flocculation tank may be improved in thermal stability by adjusting the pH to 3 to 5 using a base when the pH falls below 2 or less.

The aging tank has a different temperature condition depending on the polymer composition, and generally near the glass transition temperature (Tg).

The aging tank step may be made of one or more aging tank, it can be operated within the temperature range that the aggregation between the slurry particles does not occur can further strengthen the hardness of the slurry particles of the primary aging tank.

(d) dewatering tank stage

This step is a step of separating the slurry particles prepared in the aging tank of (c) with the mother liquor.

(e) transferring the mother liquor to the coagulation bath

This step is a step of circulating the mother liquor separated in the dehydration tank of (d) to the flocculation tank.

When the mother liquor contains ions exceeding the concentration of ionic strength required in the agglomeration tank, the mother liquor is out of the slow aggregation region when circulated 100%. By mixing a portion, the concentration of the concentration of ions required in the coagulation bath is adjusted to adjust the critical aggregation concentration, and when the coagulant used is an acid, the critical aggregation concentration may be adjusted using a base.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

[Example]

Example  One

The composition ratio of the acrylonitrile-butadiene-styrene copolymer latex used for this invention is AN: BD: SM = 13/60/27, and solid content is 42%. The aggregation process used in the invention is as follows. 2 parts by weight of magnesium sulfate (based on the latex solids) is dissolved in an aqueous solution, boiled to 80 ° C, and then coagulated by adding latex in an isothermal state. At this time, the temperature of the coagulation tank is maintained at 80 ℃.

The agglomerated slurry is steamed through a multi-steam steam nozzle of 5 kgf / cm ² during the transfer to the aging tank and aged for 10 minutes to 90 ° C in the aging tank. To recover the powder. The water content of the polymer latex resin powder obtained through the above process is shown in Table 1 below.

Example  2

The particle size distribution and physical properties of the polymer latex resin powder obtained by the same method as Example 1 except that the pressure of the multi-discharge steam in Example 1 is 3 kgf / cm ² are shown in Table 1 below. .

Example  3

The particle size distribution and physical properties of the polymer latex resin powder obtained by the same method as Example 1 except that the pressure of the multi-discharge steam in Example 1 was 10 kgf / cm ² are shown in Table 1 below. .

Comparative example  One

The particle size distribution and physical properties of the polymer latex resin powder obtained by the same method as Example 1 except that the multi-steam steam is not used in Example 1 are shown in Table 1 below.

Comparative example  2

The particle size distribution and physical properties of the polymer latex resin powder obtained in the same manner as in Example 1 except that the temperature of the aging tank is 95 ° C. without using the multi-steam steam in Example 1 are shown in Table 1 below. Indicated.

Comparative example  3

The particle size distribution and physical properties of the polymer latex resin powder obtained in the same manner as in Example 1 except that the temperature of the coagulation bath is 85 ° C. without using the multi-steam steam in Example 1 are shown in Table 1 below. Shown in

Comparative example  4

The particle size distribution of the polymer latex resin powder obtained in the same manner as in Example 1 except that the temperature of the coagulation bath is 85 ° C. and the temperature of the aging tank is 95 ° C. without using the multi-steam steam in Example 1 And physical properties are shown in Table 1 below.

Particle size distribution and physical properties of the polymer latex resin powders prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

(1) moisture content measurement method

Moisture content = ( Before drying  Latex resin Powder  Weight (g)- after drying  Latex resin Powder  Weight (g)) / Latex Resin Before Drying Powder  Weight (g) X 100

(2) Fine content (%): Content of powder less than 70 ㎛ in powdery powder of 70 ㎛-400 ㎛ size using standard mesh

Fine  % Content = less than 70 μm Powder  Weight (g) / total measurement Powder  Weight (g) X 100

Water content FINE Content (%) Example 1 24% 0.2% Example 2 28% 0.6% Example 3 23% 0.1% Comparative Example 1 32% 2.4% Comparative Example 2 30% 1.6% Comparative Example 3 29% 1.8% Comparative Example 4 28% 1.0%

Through the above Table 1, the latex resin powder of the example prepared by the method for preparing the polymer latex resin powder of the present invention has a low moisture content, a low content of fine particles, and excellent drying efficiency, and has an excellent particle size distribution. It can be seen that.

1 is a schematic view of a polymer latex resin powder apparatus according to the present invention.

Claims (10)

(a) a flocculation step of supplying a polymer latex and a flocculant to a flocculation tank to form a slurry of the polymer latex; (b) steam injection step of injecting steam to the slurry formed; And (c) transferring the slurry sprayed with steam to a aging tank for aging; In the method for producing a polymer latex resin powder comprising sequentially The steam spraying step is a method for producing a polymer latex resin powder, characterized in that the steam is injected directly to the slurry using a multi-steam steam nozzle while the aggregated slurry is transferred to the aging tank. delete The method of claim 1, The pressure of the sprayed steam is a method for producing a polymer latex resin powder, characterized in that 2 to 15 kgf / cm ² . The method of claim 1, The flocculant is a method for producing a polymer latex resin powder, characterized in that hydrochloric acid, sulfuric acid, phosphoric acid, calcium chloride, magnesium sulfate or a mixture thereof. The method of claim 1, Method for producing a polymer latex resin powder, characterized in that the temperature of the aggregation step is 60 ~ 80 ℃. The method of claim 1, Method for producing a polymer latex resin powder, characterized in that the temperature of the aging step is 70 ~ 90 ℃. The method of claim 1, After the aging step (d) a method for producing a polymer latex resin powder, characterized in that it further comprises a dehydration step of separating the mother liquid from the aged slurry. The method of claim 1, Wherein (a) the coagulation step is a method for producing a polymer latex resin powder, characterized in that carried out by one or more coagulation tank. The method of claim 1, The method of producing the polymer latex resin powder, characterized in that (c) the aging step is performed by one or more aging tanks. A polymer latex resin powder prepared using the method according to any one of claims 1 to 10.

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