JP2003213007A - Method for producing vinyl chloride based resin for paste processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably producing a vinyl chloride based resin for paste processing excellent in prevention of adhesion of a sieve screen and suppression of crushing of powder and quality when coarse particles in resin powder are removed by using a net surface-fixing type air sieve. <P>SOLUTION: In this method for producing the vinyl chloride based resin for paste processing in which coarse particles are removed by using the net surface fixing type air sieve from the resin powder obtained by drying an aqueous dispersion of a paste vinyl chloride based resin, a net surface-fixing type air force sieve to which air type screen back wash nozzle is attached is used and air having a specific absolute temperature is released under specific conditions from the air type back wash nozzle to carry out back washing of the screen. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vinyl chloride resin for paste processing. More specifically, coarse particles are removed from paste vinyl chloride resin powder by using a net-fixing type wind screen. The present invention relates to a method for producing a vinyl chloride resin for paste processing, which is excellent in productivity because it suppresses the crushing of the resin powder and the resin powder adheres little to the screen surface which is a screen.

[0002]

2. Description of the Related Art Generally, a vinyl chloride resin for paste processing is kneaded with a plasticizer and other compounding agents to form a paste sol, and the sol is processed into wallpaper, gloves and the like by coating, dipping and the like. At this time, if coarse particles that do not become a sol are present in the paste sol, defects such as streaking during coating and scratches on the surface that deteriorate the quality of the processed product occur.

For this reason, the vinyl chloride resin for paste processing is usually a vinyl chloride paste containing coarse particles after the aqueous dispersion obtained by emulsion polymerization, fine suspension polymerization and seed polymerization is dried by a spray dryer. It has been used after crushing a resin powder. However, when pulverized as described above, it becomes fine powder, and there is a problem that the workability deteriorates due to deterioration of the working environment due to dust, deterioration of fluidity, decrease of bulk specific gravity, and the like.

On the other hand, various proposals have been made for a method of removing coarse particles in a paste vinyl chloride resin powder by using a sieve without crushing them.
Japanese Patent No. 117404 proposes a method of removing coarse particles from a paste vinyl chloride resin powder by using a fixed-mesh wind-type sieve, and JP-A-11-116689.
Japanese Patent Laid-Open Publication No. 2005-242242 discloses that the relative humidity is 55 by using a fixed screen wind screen.
~ 100% of transport air is used, and the wire mesh surface of the sieve is 0.5 ~.
A method has been proposed in which the sieve is prevented from adhering to the screen surface by passing it at a speed of 10 m / sec.

However, the techniques described in the above-mentioned publicly known documents are limited to the technical range in which the adhesion of the resin powder to the screen surface of the screen is suppressed, and there is no technical study to forcibly remove the resin powder adhered to the screen surface. Therefore, none of them is sufficient to prevent the resin powder from adhering to the screen surface of the screen, and there is a problem that the resin powder after sieving is largely crushed.

[0006]

Although various methods for efficiently removing coarse particles have been investigated, coarse particles are finely powdered although they are pulverized and removed when pulverized as shown above. There is a problem that the powder characteristics deteriorate.

Further, when a screen-fixing type wind screen is simply used, the resin powder adheres to the screen surface, which is a screen, and the efficiency of the screen decreases, and the resin powder after crushing is crushed. There was a problem such as a large size.

Therefore, in the present invention, when the coarse particles in the paste vinyl chloride resin powder are removed by using a fixed-mesh wind power sieve without pulverization, the resin powder on the screen, which is the sieve, is removed. It is an object of the present invention to provide a method for producing a vinyl chloride resin for paste processing, which has less body adhesion and less crushing of resin powder after sieving.

[0009]

Means for Solving the Problems As a result of diligent studies on the above problems, the present inventors have found that when using a fixed-mesh wind-type screen, a specific screen screen backwashing device is attached, and By using backwashing air, it was found that the crushing of the paste vinyl chloride resin powder can be suppressed, and it is effective in removing the deposits of the paste vinyl chloride resin powder on the screen surface of the screen, thus completing the present invention. Came to let.

That is, the present invention is a vinyl chloride resin for paste processing for removing coarse particles from a resin powder obtained by drying an aqueous dispersion of a paste vinyl chloride resin with a spray dryer by using a screen-fixing wind screen. In the manufacturing method of No. 2, a fixed net surface type wind screen equipped with a pneumatic screen backwash nozzle is used, and air having an absolute humidity of 0.028 kg-water / kg-air or less is supplied from the air screen backwash nozzle at a pressure of 0.
The present invention relates to a method for producing a vinyl chloride resin for paste processing, which comprises discharging under a condition of ^{2 to} 0.6 MPa and a capacity of ^{2 to 20} m ³ / m ² -screen area · min and backwashing the screen.

The present invention will be described in detail below.

The vinyl chloride resin for paste processing in the present invention is a vinyl chloride monomer or a monomer mixture mainly composed of a vinyl chloride monomer (hereinafter referred to as vinyl chloride) in the presence of a surfactant and a polymerization initiator. Is a polyvinyl chloride resin obtained by polymerizing a (monomer-based monomer) in an aqueous medium,
As the polymerization method, it is preferable to polymerize a vinyl chloride monomer by an emulsion polymerization method, a fine suspension polymerization method, a seed emulsion polymerization method, a seed polymerization method such as a seed fine suspension polymerization method, or the like, and particularly, a seed polymerization method, Furthermore, it is preferable to polymerize by seed fine suspension polymerization. At this time, in any polymerization method, 30
It is preferable to polymerize in the temperature range of -80 ° C.

The vinyl chloride monomer as used herein is a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer. Examples of vinyl monomers copolymerizable with the monomers include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate, and vinyl benzoate; vinyl esters such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Saturated carboxylic acid or its anhydride; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate; Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate; Maleic acid ester, fumaric acid Unsaturated carboxylic acid esters such as esters and cinnamic acid esters; vinyl methyl ether, vinyl amyl ether, Vinyl ethers such as nyl phenyl ether; monoolefins such as ethylene, propylene, butene, pentene; vinylidene chloride, styrene and its derivatives, acrylonitrile, methacrylonitrile, etc., and one or more of these vinyl monomers. Can be used in.

Examples of the surfactant include dialkyl sulfosuccinate, alkyl benzene sulfonate, alkyl sulfate and the like, and these can be used alone or in combination of two or more kinds.

Examples of the polymerization initiator include water-soluble initiators such as potassium persulfate, ammonium persulfate and hydrogen peroxide; aromatic diacyl peroxides such as benzoyl peroxide and p-chlorobenzoyl peroxide; caproyl peroxide, Aliphatic diacyl peroxides such as lauroyl peroxide; azo compounds such as azobisisobutyronitrolyl and azobisisovaleronitrile; peroxydiesters of organic acids such as t-butylperoxypivalate; diisopropylperoxydicarbonate , Peroxydicarbonates such as dioctyl peroxydicarbonate, and oil-soluble initiators such as acetylcyclohexylsulfonyl peroxide. And these can be used individually or in combination of 2 or more types.

As a method for drying the aqueous dispersion of the paste vinyl chloride resin in the present invention, a spray drying method using a spray drying apparatus is used because thermal deterioration during drying can be alleviated. There is no limitation on the type of spray drying device at this time, and any commonly used spray drying device may be used.
AY DAYING HANDBOOK "(K. Mas
ter, 3rd edition, 1979, George Godw
Published in Limited) 121 pages 4.10
There are various spray dryers listed in the figure,
The operating conditions in this case are generally used conditions, and in the present invention, for example, the drying outlet temperature is 40
Operating in the range of ~ 90 ° C, preferably 40-70 ° C,
It is particularly preferably dried at 40 to 65 ° C.

The average particle size of the paste vinyl chloride resin powder after drying by the spray dryer is usually 20 to 200 μm.
In many cases, a small amount of coarse particles agglomerated during drying are mixed. In the production method of the present invention, the average particle size is 20 to 100 μm in order to efficiently remove the coarse particles.
It is preferably m, particularly preferably 20 to 80 μm, and more preferably 20 to 70 μm. Here, there is no particular limitation on the method of adjusting the average particle size of the paste vinyl chloride resin powder after drying. For example, when using a rotary disk type spray dryer, it is proposed by Fridman, Herring, etc. However, a method of adjusting the diameter of the rotating disk, the amount of spray liquid, and the number of rotations of the rotating disk can be adopted.

According to the present invention, the coarse particles in the paste vinyl chloride resin powder are not crushed and removed, and the coarse particles are removed by operating under a specific condition using a specific wind-screen with a fixed mesh surface. Is efficiently removed, and a fixed-mesh screen windscreen with an air-screen backwash nozzle is used as the fixed-mesh screen windscreen, and the absolute humidity of 0. 028 kg-water / kg-air below air pressure 0.2-0.6 MPa,
It is characterized in that the screen is backwashed by discharging under the condition of a capacity of ^{2 to 20} m ³ / m ² -screen area · min.

Incidentally, FIG. 1 shows an example of a sectional view of a fixed-mesh type wind screen which can be used for carrying out the present invention. 1 in FIG. 1 indicates an inlet of the paste vinyl chloride resin powder after drying, 2 indicates an outlet of the paste vinyl chloride resin for sieving, 3
Indicates a coarse particle outlet after sieving, 4 indicates an air inlet for backwashing, 5 indicates a casing, 6 indicates a circular screen which is a sieve, 7 indicates a pneumatic screen backwashing nozzle,
8 indicates a shaft, and 9 indicates a rotary joint.

The fixed mesh surface type wind screen used in the present invention is provided with an air screen backwash nozzle, and the air screen backwash nozzle discharges air from the nozzle to backwash the screen surface. Any nozzle can be used as long as it can prevent adhesion to the screen, clogging of the screen, etc. and can achieve the object of the present invention.

In the present invention, air having an absolute humidity of 0.028 kg-water / kg-air or less is supplied from the air-type screen backwash nozzle at a pressure of 0.2 to 0.6 MPa and a capacity of 2 to 20 m.
³ / m ² -Screen area-min It is released under the condition of min. The absolute humidity of the air used for backwashing is 0.028k.
If the amount is less than g-water / kg-air, the production method of the present invention can be carried out without any particular problems. In particular, it is excellent in removing the paste vinyl chloride resin powder adhering to the screen surface and economically adjusting the air for backwashing. 0.020k because it is possible to do
It is preferably g-water / kg-air or less, more preferably 0.015 kg-water / kg-air or less. Here, the absolute humidity of air is 0.028 kg-water /
If it exceeds kg-air, the efficiency of removing the paste vinyl chloride resin powder adhering to the screen surface is lowered, and it becomes difficult to stably produce the vinyl chloride resin for paste processing. Regarding the lower limit of the absolute humidity of the air used for backwashing, the lower it is, the better the removal efficiency of the paste vinyl chloride resin powder adhering to the screen surface is, but it is a practical economic factor. Therefore, it is preferable that the absolute humidity is 0.13 g-water / kg-air or more.

The pressure at which the backwash air is discharged from the pneumatic screen backwash nozzle is 0.2 to 0.6 MPa.
In particular, 0.2 to 0.5 MPa is preferable, because it is excellent in removing the paste vinyl chloride resin powder adhering to the screen surface, and the possibility of crushing the resin powder is low.
Particularly preferably, it is 3 to 0.4 MPa. here,
If the pressure when discharged from the air-type screen backwash nozzle is less than 0.2 MPa, the removal efficiency of the paste vinyl chloride resin powder adhering to the screen surface will decrease, and the production of vinyl chloride resin for paste processing will be reduced. It becomes difficult to manufacture stably. On the other hand, when the pressure when discharged from the pneumatic screen backwash nozzle exceeds 0.6 MPa,
The crushing of the paste vinyl chloride resin powder after sieving becomes severe. Further, as the capacity of the air for backwashing, the capacity is 2 to 20 m.
³ / m ² -screen area · min, which is particularly excellent in removing the paste vinyl chloride resin powder adhering to the screen surface, and has a low risk of crushing the resin powder.
8.5 m ³ / m ² -screen area min is preferable,
In particular, it is preferably 3.5 to 18 m ³ / m ² -screen area · min. Here, the volume of backwash air is 2 m
³ / m ² -Screen area · If it is less than min, the removal efficiency of the paste vinyl chloride resin powder adhering to the screen surface is reduced, and the vinyl chloride resin for paste processing can be manufactured stably. It will be difficult. On the other hand, when the volume of the backwash air exceeds 20 m ³ / m ² -screen area · min, the paste vinyl chloride resin powder after sieving is severely crushed. The backwash air capacity here means a numerical value obtained by dividing the backwash nozzle blown air amount (m ³ / min) by the screen area (m ² ).

Further, the screen, which is a screen attached to the mesh surface fixed type wind screen used in the present invention, can efficiently remove the paste vinyl chloride resin powder adhering to the screen surface. Therefore, a circular screen is preferable. Here, the circle means a circle or an ellipse.

In the present invention, in order to efficiently remove coarse particles by using a fixed mesh type wind screen, the differential pressure before and after the screen, which is a screen, should be within the range of 0.3 to 10 KPa. Is more preferable, and further preferably 0.4 to 8 KPa, and particularly preferably 0.5 to 6 KPa. And, as the supply rate for supplying the paste vinyl chloride resin powder to the screen which is the screen at that time, the adhesion of the resin powder to the screen surface can be prevented,
1000-2600 kg per unit area of screen, which is a screen, because productivity deterioration due to yield can be prevented.
/ M ² · Hr is preferably supplied at a speed of 1
000 to 2400 kg / m ² · Hr is preferable, especially 1
It is preferably 000 to 2000 kg / m ² · Hr.

Regarding the screen openings which are sieves, the smaller the openings are, the more preferable it is in terms of removing coarse particles, but there is no deterioration in quality when the vinyl chloride resin for paste processing after sieving is processed as a paste sol. 80 to 200 μm is preferable, 80 to 120 μm is more preferable, and 80 to 120 μm is particularly preferable, since the yield can be prevented when the paste vinyl chloride resin powder is sieved and the productivity can be improved.
It is preferably 5 μm. In addition, the material of the screen is not particularly limited as long as the purpose as a screen is achieved, and among them, it has excellent corrosion resistance and causes a problem of contamination due to corrosion of the obtained vinyl chloride resin for paste processing. It is preferably made of stainless steel because of low possibility, and particularly preferably made of SUS304 or SUS316 because of excellent corrosion resistance to vinyl chloride monomer present as an unreacted monomer.

In the present invention, a screen backwash nozzle bar provided with an air type screen backwash nozzle is provided because it is excellent in the efficiency of removing the paste vinyl chloride resin powder adhering to the screen surface which is the screen, and the nozzle bar rotates. The nozzle bar rotation speed is preferably 20 to 400 r.p.m. p. m. Is preferable, and particularly 40 to 360 r. p. m. Is preferred. The structure of the nozzle bar is not particularly limited, but a cross-shaped blow-out bar is preferred because the screen surface can be efficiently backwashed.

The method of the present invention has a problem with the conventional method for removing coarse particles using a fixed mesh surface type wind screen, which is a problem caused by adhesion of resin powder on the screen surface,
It is possible to solve the crushing of the resin powder during the operation, to prevent the resin from adhering to the screen surface of the screen, and to suppress the crushing of the resin powder.

[0028]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

The evaluation method and the like in the examples will be described in detail below.

-Evaluation of Adhesion of Resin Powder to Sieve Screen-
The state of adhesion of the resin powder to the sieve screen after the sieving treatment with the screen-fixing type wind screen was visually evaluated. ○: No resin powder adhered to the screen surface. X: Resin powder adhered to the screen surface.

-Measurement of Average Particle Size- A laser diffraction / scattering type particle size measuring device (manufactured by Horiba, Ltd.) was used with a sample whose concentration was adjusted so that the laser transmittance of the measuring sample was 75 to 85%. , Trade name LA-
700) was used to measure the average particle size.

-Measurement of undispersed substance in paste sol- 100 parts by weight of the obtained vinyl chloride resin for processing paste was mixed with 60 parts by weight of di-2-ethylhexyl phthalate, and a dissolver mixer (TOKUSYU KI) was used.
KA KOGYO, trade name T.K. K. HOMO DIS
PER MODEL 7C) at 25 ° C, 800 rpm
The paste sol was prepared by kneading for 3 minutes under the above conditions.

The paste sol was poured into a groove of a crushed gauge, and was squeezed with a scraper to a thickness of 25 in the groove.
A layer of sol was prepared so as to continuously change from 0 μm to 0 μm, the thickness of the layer at the portion where the crush appeared was read, and the size of the undispersed substance in the paste sol was measured.

Preparation Example 1 (Preparation of Aqueous Dispersion of Seed Particles) 360 kg of deionized water, 300 kg of vinyl chloride monomer, 3,5,5 as polymerization initiator in 1 m ³ autoclave
-Trimethylhexanoyl peroxide 3 kg, 15
After charging 5.0 kg of an aqueous solution of sodium dodecylbenzenesulfonate in weight%, the mixture was homogenized for 3 hours using a homogenizer, and then the temperature in the system was raised to 40 ° C. to start the polymerization reaction. Then, after the polymerization pressure was reduced, the unreacted vinyl chloride monomer was recovered to prepare an aqueous dispersion of seed particles.

Synthesis Example 1 (Preparation of Paste Vinyl Chloride Resin Powder) 350 kg of deionized water, 400 kg of vinyl chloride monomer, 2 kg of 20% by weight sodium dodecylbenzenesulfonate aqueous solution in a 1 m ³ autoclave, obtained by Preparation Example 1 After charging 44 kg of the obtained aqueous dispersion of seed particles,
The temperature of the polymerization system was raised to 64 ° C. to start the polymerization. Then, 20 kg of a 20% by weight sodium dodecylbenzenesulfonate aqueous solution was continuously added from the start of the polymerization to the end of the polymerization.

The polymerization reaction was stopped when the polymerization pressure dropped 0.6 MPa from the saturated vapor pressure of the vinyl chloride monomer at 64 ° C., the unreacted vinyl chloride monomer was recovered, and the paste vinyl chloride resin was dispersed in water. A liquid was obtained.

Next, the obtained aqueous dispersion of the paste vinyl chloride resin was dried by a rotary disk type spray dryer (Ashizawa Niro Atomizer Co., Ltd., trade name S-25R) at a dryer inlet temperature of 140 ° C. and a dryer outlet. Temperature 50 ° C, disk rotation speed 20000r. p. m. A paste vinyl chloride resin powder was obtained by drying with.

Example 1 A fixed mesh surface type wind screen (manufactured by Shin Tokyo Kikai Co., Ltd., trade name Hiboulder NR) equipped with pneumatic screen backwash nozzles composed of cross-shaped blowout nozzle bars intersecting each other on the back side of a circular screen. -300 type), a circular screen made of SUS304 with a diameter of 300 mm, a screen opening of 104 μm, and a material of SUS304 was installed on the mesh-type fixed buoyancy sieve.
1200 kg / of the paste vinyl chloride resin powder obtained by the above, so that the differential pressure before and after the screen becomes 3 KPa.
It was supplied at a rate of m ² · Hr to obtain a vinyl chloride resin for paste processing from which coarse particles were removed.

At this time, the air discharged from the air type screen backwash nozzle has an absolute humidity of 0.005 kg-.
Water / kg-air, pressure 0.35 MPa, capacity 18
m ³ / m ² −screen area · min. Further, the rotational speed of the pneumatic screen backwash nozzle was 360 rpm. p.
m. Met. Table 1 shows the average particle size of the obtained vinyl chloride resin for paste processing and the evaluation results of undispersed substances in the paste sol.

Example 2 For paste processing by the same method as in Example 1 except that air having an absolute humidity of 0.015 kg-water / kg-air was used as the air discharged from the air type screen backwash nozzle. Table 1 shows the average particle size after adjustment of the vinyl chloride resin and the evaluation results of the undispersed substance in the paste sol.

Example 3 A vinyl chloride resin for paste processing was prepared in the same manner as in Example 1 except that the pressure of the air discharged from the air type screen backwash nozzle was 0.5 MPa, and the average particle size after adjustment was adjusted. Table 1 shows the diameters and the evaluation results of the undispersed substances in the paste sol.

Example 4 A vinyl chloride resin for paste processing was prepared in the same manner as in Example 1 except that the volume of air discharged from the air type screen backwash nozzle was 8 m ³ / m ² -screen area · min. Table 1 shows the average particle size after adjustment and the evaluation results of the undispersed substances in the paste sol.

Example 5 Paste vinyl chloride resin powder was fed at 2200 kg /
A vinyl chloride resin for paste processing was adjusted in the same manner as in Example 1 except that the speed was m ² · Hr, and the average particle size after adjustment and the evaluation results of undispersed substances in the paste sol are shown in Table 1. Shown in.

Example 6 The pressure difference before and after the circular screen was set to 10.5 KPa, and the paste vinyl chloride resin was supplied at 2700 kg / m ² · H.
A vinyl chloride resin for paste processing was prepared in the same manner as in Example 1 except that the mixture was supplied at a rate of r, and the average particle size after adjustment and the evaluation results of undispersed substances in the paste sol are shown in Table 1.

Comparative Example 1 Except that the absolute humidity of the air discharged from the air type screen backwash nozzle was 0.030 kg-water / kg-air.
A paste vinyl chloride resin was prepared in the same manner as in Example 1, and the average particle size after adjustment and the evaluation results of undispersed substances in the paste sol are shown in Table 1.

Adhesion of the paste vinyl chloride resin powder to the surface of the screen was observed, and it was necessary to perform a removing operation.

Comparative Example 2 A paste vinyl chloride resin was prepared in the same manner as in Example 1 except that the pressure of the air discharged from the air type screen backwash nozzle was 0.15 MPa.
Table 1 shows the evaluation results of the undispersed substances in the paste sol.

Adhesion of the paste vinyl chloride resin powder to the screen surface was observed, and it was necessary to perform a removing operation.

Comparative Example 3 A paste vinyl chloride resin was prepared in the same manner as in Example 1 except that the pressure of the air discharged from the air-type screen backwash nozzle was 0.7 MPa. Table 1 shows the evaluation results of the undispersed substances in the paste sol.

The obtained paste vinyl chloride resin powder was crushed and the average particle size was as small as 19 μm.

Comparative Example 4 A paste vinyl chloride resin was prepared in the same manner as in Example 1 except that the air discharged from the pneumatic screen backwash nozzle had a capacity of 1 m ³ / m ² -screen area · min. Table 1 shows the average particle size after adjustment and the evaluation results of undispersed substances in the paste sol.

Adhesion of the paste vinyl chloride resin powder to the surface of the screen was observed, and it was necessary to perform a removing operation.

Comparative Example 5 Except that the air discharged from the pneumatic screen backwash nozzle had a capacity of 30 m ³ / m ² -screen area · min.
A paste vinyl chloride resin was prepared in the same manner as in Example 1, and the average particle size after adjustment and the evaluation results of undispersed substances in the paste sol are shown in Table 1.

The obtained paste vinyl chloride resin powder was crushed and the average particle size was as small as 18 μm.

Comparative Example 6 The paste vinyl chloride resin powder obtained in Synthesis Example 1 was evaluated without sieving. Table 1 shows the evaluation results of the undispersed substances in the paste sol.

Large undispersed substances were found in the paste sol prepared from the obtained paste vinyl chloride resin powder.

[0057]

[Table 1]

EFFECT OF THE INVENTION The production method of the present invention is excellent in preventing the screen screen from adhering when removing coarse particles in the resin powder by using the fixed-mesh type wind screen, and also in suppressing the crushing of the powder. The present invention stably produces a vinyl chloride resin for paste processing, which is excellent in quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a fixed mesh surface type wind screen used for carrying out the present invention.

[Explanation of symbols] 1 Dry powder inlet 2 Powder outlet after sieving 3 Coarse particle outlet 4 Backwash air inlet 5 casing 6 sieve circular screen 7 Air type screen backwash nozzle 8 shafts 9 Rotary joint

Claims (5)

[Claims] 1. A method for producing a vinyl chloride resin for paste processing, wherein coarse particles are removed from a resin powder obtained by drying an aqueous dispersion of paste vinyl chloride resin by a spray dryer by using a screen-fixing type wind screen. , Using a fixed net surface type wind screen equipped with a pneumatic screen backwash nozzle, and from the pneumatic screen backwash nozzle an absolute humidity of 0.028 kg-water /
Vinyl chloride for paste processing, characterized in that air equal to or less than kg-air is released under the conditions of a pressure of 0.2 to 0.6 MPa and a capacity of ^{2 to 20} m ³ / m ² -screen area / min, and the screen is backwashed. Method for producing a base resin. 2. A screen-fixing wind-type sieve provided with a circular screen is used as a sieve, and the differential pressure before and after the circular screen is within the range of 0.3 to 10 KPa, and the feed rate of the resin powder after drying is Circular screen 100 per unit area
The method for producing a vinyl chloride resin for paste processing according to claim 1, wherein the amount is 0 to 2600 kg / m ² · Hr. 3. A vinyl chloride-based paste processing paste according to claim 1, wherein the screen has an opening of 80 to 200 μm and the material is SUS304 or SUS316. Resin manufacturing method. 4. A pneumatic screen backwash nozzle with a rotational speed of 20.
~ 400r. p. m. 4. The method for producing a vinyl chloride resin for paste processing according to claim 1, wherein the screen surface is backwashed while being rotated. 5. The air screen backwash nozzle bar is an air screen backwash nozzle bar in which nozzles are attached to intersecting cross-shaped blow-out bars. Of the method for producing a vinyl chloride resin for paste processing according to claim 1.