JPS59102935A - Recovery of vinyl chloride resin - Google Patents

Abstract

PURPOSE:To recover a granular resin efficiently having improved characteristics as plastisol, etc., having improved flow properties, and low scattering properties, by blending water dispersion of vinyl chloride resin with an organic medium by a specific treatment, separating the prepared particulate agglomerate, drying it. CONSTITUTION:In blending 100pts.wt. resin with preferably 2-15pts.wt. organic medium(e.g., dioctyl phthalate, diethylene glycol dibenzoate, butyl oleate, mineral spirit, etc.) slightly soluble in water neigher and dissolving nor swelling the vinyl chloride resin, ultrasonic treatment is carried out in the first half of blending and a means other than ultrasonic treatment(method using a high-speed rotary continuous blender, etc.) is employed in the latter half of the blending, so that the vinyl chloride resin is separated from the aqueous phase as a particulate agglomerate, it is dried and recored.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering vinyl chloride (tiI resin), particularly granular vinyl chloride resin used for paste processing.

Normally, when paste-processing vinyl chloride resin, the vinyl chloride resin (hereinafter sometimes referred to as resin) manufactured for paste processing is mixed with plasticizers, solifiers, and pigments, fillers, etc. as necessary. A method is adopted in which the plastisol is mixed with a compounding agent to form a liquid plastisol and then subjected to a molding process. Then, a molded article is obtained by shaping the plastisol into a planar shape by means of casting, coating, dipping, etc., and heating and melting and solidifying it. Therefore, the fluidity properties of plastisol are extremely important properties that affect the formability of paste processing, and the reality is that great effort and ingenuity are put into the formulation, especially in the quality design of the resin. be. On the other hand, in addition to the flow characteristics of plastisol, the characteristics of molded products, especially their appearance,
The major influence on strength is the dispersibility of the powder compound into the liquid compound. If powder compounding agents, such as resins, remain in the sol as coarse aggregates, they not only affect the fluidity of the plastisol, but also cause clogging during transportation of the plastisol and streaks during coating processing. Problems such as pulling, roughness of the molded product skin, matting, etc.
Furthermore, it causes problems such as a decrease in strength. In consideration of such problems in paste processing, the reality is that the resin is usually supplied as a fine powder that passes through a JIS 625 mesh. The method for producing resin for this purpose is to emulsify or suspend vinyl chloride or a monomer mixture mainly composed of vinyl chloride in the presence of a radical-generating polymerization initiator and an emulsifier to obtain a particle size of 0. 05
A method has been adopted in which an aqueous dispersion of a spherical resin of ~5 μm is obtained and this aqueous dispersion is spray-dried.

However, the resin obtained by this method contains all the nonvolatile components in the aqueous resin dispersion, which causes a decrease in properties such as thermal stability, water resistance, and transparency of the molded product. Furthermore, in normal spray drying, the resin particles in the sprayed aqueous dispersion are dried and captured as a solid aggregate as the water evaporates, so in order to ship as a product, a pulverization process is required. Even with such treatments, dispersion of aggregated particles is often not achieved through simple mixing during plastisol production. Furthermore, as mentioned earlier, conventional resins are fine powders, so
Not only does this cause a reduction in work efficiency, such as powder scattering during product bagging and during plastisol production when opening bags and mixing, but the powder has poor fluidity, making automatic weighing and transportation difficult. It is.

As a result of studying the current problems of vinyl chloride resin for paste processing, the present inventor discovered that vinyl chloride resin,
Especially for aqueous dispersion of vinyl chloride JL resin for paste processing.
By adding and mixing an organic liquid that is a B bath and does not dissolve or swell the vinyl chloride resin to water, the vinyl chloride A resin is separated from the water phase as a granular aggregate, and then dried to form a chlorinated When recovering Vinyl A resin, a mixture of an aqueous dispersion and an organic liquid is subjected to ultrasonic treatment in the first stage and a combination of methods other than ultrasonic treatment in the latter stage, resulting in good fluidity and scattering properties as a powder. It was confirmed that granular vinyl chloride resin can be obtained with extremely high efficiency, and when made into plastisol, it has a high level of fine dispersibility and gives molded products with excellent thermal stability, water resistance, and transparency. However, the present invention was completed.

The method of the present invention consists of the following basic steps:
1) A first step of mixing an aqueous resin dispersion and an organic liquid to aggregate the resin via the organic liquid; 2) Separating the aqueous phase from the mixed liquid containing the resin aggregate obtained in the first kneading process. 5) a 6th step of drying the resin aggregate from which the aqueous phase has been removed; and, if necessary, 4) the resin in the aqueous phase separated in the 2nd step, Q%' 1 step The fourth step consists of mixing the raw materials used in the step.

The aqueous dispersion of vinyl chloride resin used in the present invention is a conventional emulsion U1 (based on vinyl chloride monopolymerization or vinyl chloride produced by polymerization or suspension polymerization).
water of a copolymer of this with an olefinic monomer such as vinyl acetate, monopacked vinylidene, ethylene, globylene, butene, acrylonitrile, acrylic ester, methacrylic ester, or maleic acid. It refers to a dispersion liquid, and is not particularly limited as long as it can be subjected to normal processing. If necessary, a vinyl chloride resin for weight expansion can also be included. The content of vinyl chloride resin in the aqueous dispersion is 10 to 70 liters by weight. That is, it is convenient to use the aqueous dispersion of vinyl chloride resin after polymerization as it is, but it is also possible to partially dehydrate it or add water if necessary. If it is less than 10% by weight, the amount of wastewater will be too large compared to the product amount, resulting in uneconomical results, and if it exceeds 70% by weight, the viscosity of the mixture of aqueous dispersion and organic liquid will increase significantly. Therefore, the operation becomes a national crisis.

The organic liquid added to the aqueous dispersion of vinyl chloride resin is one that is similar to water and does not dissolve or swell the resin during separation and recovery in the present invention. Generally, the organic liquid used has a melting point of 20C or less and a boiling point at normal pressure of at least the temperature during separation and recovery of the present invention, preferably 200U or more. If an organic liquid having a boiling point lower than the temperature at the time of separation and recovery is used, additional equipment is required for recovery because the organic liquid evaporates, which is not economical. Of course, even if it does not meet the above-mentioned conditions as a single product, it may be used as a mixture as long as it satisfies the above-mentioned requirements.

There are two reasons why organic liquids are required to be resistant to water. First, after mixing with the aqueous dispersion,
The purpose of this is to reduce the amount of solids transferred to the aqueous phase to be separated, prevent the loss of organic liquid, and reduce wastewater treatment costs.Secondly, the resin particles dispersed in water are transferred through a specific liquid. This is because, in order to achieve this result, it is necessary that the @J3 phantom antibody exists as a liquid phase with an interface between the tree 11tY particles and water.

In addition, if the liquid used is one that causes the resin 17 to swell at the temperature during separation and recovery in the present invention, the hl11Ff particles may be deformed or altered, which is disadvantageous. be. In addition, since most of the organic 1(k) compound used in the present invention remains in the product resin, it is necessary to avoid any substances that have a negative effect on the operability, workability, and quality of the molded product during processing. From the above points, it is most natural and rational to use a liquid compounding agent used in ordinary processing as an organic material.

Examples of the organic liquid in the present invention include the following.

ill Phthalates such as dioctyl phthalate, dinonyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, etc. Alkyl ester-based oJ plasticizers (Σl Aromatic carvone 112 ester-based plastics such as trioctyl trimellitate and diethylene glycol dipenzoate (31 Aliphatic dibasic acids such as dioctyl adipate, dibutyl sebacate, and dioctyl tetrahydrophthalate) Ester plasticizer i41 tIJ octyl phosphinyl 1-,) phosphorus such as l'loloethyl phosphate etc. Ester type 01 plasticizer 5) diethylene glycol cacrylate, 1,
Fatty acid dalicol ester plasticizers such as 4-butylene dalicol-di-2-ethylhexanoate (6-polyester plasticizer 17) Oleic acid butyl, methyl acetyl ricinoleate, 2.2.4-trimethyl-1,6 Fatty acid esters such as pentanediol diisoptylate, epoxy esters such as epoxidized dog σ oil, epoxy octyl stearate, chlorinated fatty acid methyl, chlorinated paraffin such as chlorinated paraffin, aliphatic esters such as succinic dioctyl, etc. Basic acid ester-based secondary IIJ plasticizers (8) Petroleum-based mineral spirits, mineral turpentine, etc., long-chain alkylbenzene-based thinners such as dodecylbenzene + 9r Liquids such as AM flucol, liquid paraffin, higher fatty acid argyl esters, etc. The use of lubricant organic liquids in aqueous dispersions
The amount is usually 0.5 to 20 parts per tonne, preferably 2 to 15 parts per tonne. If it is less than 05 overlap part, a θ resin is present and cannot be aggregated sufficiently, and if it exceeds 20 overlap part, it will be obtained as a nor-shaped aggregate. Even if it is obtained as a granular aggregate, it is difficult to remove the residual liquid in the drying process due to the large number of points contained in a single molecule, resulting in a reduction in fresh sweat efficiency. It's bad.

When ultrasonicating a mixture of vinyl chloride resin and an aqueous separating solution, there are no particular restrictions as long as the ultrasonic waves are applied uniformly to the entire mixed phase. Commercially available ultrasonic transmitters can be used.

The material temperature during ultrasonic treatment is 20-70C1, preferably 2
It is necessary to carry out the test in the range of 0 to 50C.

Therefore, the output and processing time should be adjusted so that the ultrasonic processing conditions do not deviate from the temperature range.

If processing is carried out under conditions exceeding 70C, swelling and dissolution of the resin by the organic liquid will be promoted11, and strong coalescence of the resins will occur due to heat, which will significantly impair the dispersibility of the resin during processing. Furthermore, if the aqueous resin fraction and organic 7M substance are mixed in the order of using a method other than ultrasonic treatment in the first step and then performing ultrasonic treatment in the second step, a high degree of fine dispersion during processing cannot be achieved. To be foolish, the resin recovery efficiency actually decreases.

The ultrasonic treatment according to the present invention improves the dispersibility of the mixed phase and at the same time changes the surface shape of the resin particles before aggregation, making it easier for the resin to aggregate by step-wise mixing.
Furthermore, it is presumed that redispersion during the product processing stage becomes easier.

The ultrasonicated mixture is then led to a mixing step for the purpose of aggregating the resin. As a mixing method in this step, any known method other than ultrasonication can be adopted, but
Since the degree of mixing i has a large influence W on the mixing efficiency due to the organic liquid of the resin, it is preferable that the mixing power per unit volume of the mixing device is greater than IKW/M''-C1 mixing time. The product should be greater than or equal to 4 KW-Hr/M''. As a mixing device, from the viewpoint of uniformity and continuity of mixing, it is preferable to use a high-speed rotating continuous mixing tube, a curved type, or a multi-blade type continuous mixing tank, but ordinary stirring 11! Type I mixing machines and stationary warmers can also be used.

(Mixing liquid and 4fJ1 fat water 1 (1; dispersion is at a temperature of 20 to 70G, and the organic dispersion used is resin 1'6)) However, the higher the temperature, the higher the expansion rate of the organic liquid, so it is preferable to keep the temperature below 50C.If the temperature exceeds 70C, the organic liquid will be absorbed into the resin. Not only is this accelerated, but the resin may soften and coalesce, making the final product no longer suitable for processing.

In addition, the time for the ultrasonic wave processing set up by +JfJ and the other mixing processing in the latter stage may be determined appropriately within the 4α range where no overheating occurs, but the first stage is usually several seconds to several tens of minutes, and the latter stage is generally It has the same root as the previous stage, 11i, or longer.

Next, the aqueous resin is separated from the resin aggregate through the organic plate, and the shape of the captured resin mixture is reduced.
] Then, 7 tons were washed using a known method. However, in order to prevent the trees from softening and coalescing, the temperature must be kept at 20-70G.

The particles separated in the separation process are then sent to a drying process, where the organic substance and accumulated water are removed.In this drying process, a widely known drying device is used However, it is necessary to set conditions such that the strength of resin aggregation and coalescence does not impair dispersibility during processing. That is, the temperature of the dried food product during the drying process is set to 70C or higher, preferably 50C or lower.

The obtained dry powder has good fluidity and has little fragility, and due to its density, physical properties such as viscosity characteristics when made into plastin and thermal stability when made into molded products are also reduced. It is something that

Next, a detailed explanation of the present invention will be given using an actual gun.
The recovery efficiency of granular vinyl chloride resin was calculated using the following formula.
(Powdery nature of fat, sol (resin soy and di-2-ethyl phthalate) mixed in a 30Fj-trary machine and subjected to W', +aN) The angle of repose explained here shows the ease of fluidity of the powder, and the small value indicates the flow!
IJtI ambiguous O bulk specific gravity.

This is the apparent density of the powder, and the smaller the value, the better the handling properties.

After placing the adherent sample on the paper and vibrating it horizontally, the sample is carefully cleaned to remove any amount of horizontal residue that may have adhered to the paper.

The less the better.

Viscosity Sol temperature ('25CTO) value when run at 6 rpm TdillM in Brookfield BM type viscosity Utjl Locowell 4 (first day), and when left at 023C for 7 days (7L (after)).

It indicates the particle size of the resin particles in the North Fines sol, and the higher the number, the finer it is (8 is the finest and O is the smallest). The heat-stable sol was injected into an aluminum mold, and the color tone changed after 60 minutes in a 190C hot air atmosphere.
Displayed in 5 levels: E (large change).

Example Aqueous dispersion of J-vinyl 4i11 fat for paste processing (
Solid content @ 55 tons per minute) and di-2-ethylhexyl phthalate at 45% each (J me/min, 7
The liquid was supplied to a stainless steel cylindrical container equipped with an internal ultrasonic transmitter (output 150 W) and equipped with "liquid supply/drainage" at both ends at a supply speed of rnl/min. After the treatment was carried out, the treatment mixture was continuously discharged. Next, install this mixer inside @ diameter 9LJ
A 1-Yen-1 Zhao-type stainless steel mixer with an internal volume of 6.8E and a large number of stirring ends of n was equipped with 7 tons of personnel and a rotation speed of 500 rpm.
Processed continuously. The spherical resin composition was separated from the mixed solution taken for 5 minutes using a 60-mesh wire mesh, and the material on the wire mesh was dehydrated with a magnetic core to obtain 859y- wet granules. When this was dried in a hot air circulation type dryer at 55C for 12 hours, 593 jib's 4 months of drying was done.
I was beaten.

Example Aqueous content Vl of vinyl chloride resin for paste processing! itj+
(solid content 40-76) and dioctyl adipate 517 were placed in a wide robolibin with an internal volume of 500 ml, and this was washed in an ultrasonic cleaner (output 600 W) with an internal volume of about 5 e filled with water. After being immersed in water for 10 minutes and subjected to ultrasonic treatment b (fx), the polybottle containing the contents was shaken for 10 minutes with shaking.Then, the spherical resin composition was separated from the entire mixture using a 60-mesh wire mesh. When the material on the wire mesh was centrifugally dehydrated, 100 y- of wet m1 granules were obtained.

When this was dried for 12 hours in a hot air circulation type dryer at 35C, 727 resin (Bl) was obtained.

Example 5 A mixture of di-2-ethylhexyl phthalate and 5 parts by weight of resin was added to an aqueous dispersion of vinyl chloride resin for paste processing (solid content: 60 pieces i), and the opening area was Discharge pressure 15 kg from a small hole with a diameter of 5 mra''71B'
The ultrasonic treatment was carried out by injecting the liquid into a firing blade located approximately 55 mm away from the small hole. Next, 65,001 portions of this treated mixture were taken and placed in a stainless steel container with an internal volume of 6 liters per day.
After mixing for 15 minutes at a rotational speed of pm, the mixture was
1iIi When the same treatment as in Example 1 was carried out, 9107 wet 7 loose granules and 68 filter 1 :h'i dry resin particles (01) were obtained.

Comparative example 1 Ultrasonic treatment 38! Experiment 2 was conducted in the same manner as in Example 1, except that . The resulting wet granules and dry resin particles (JJ
The weight of each is 295j? , 210p-0 Comparative Example 2! 13 An experiment similar to Experiments 1 and 2 was conducted except that sonication was not performed. wet granules and dry resin particles (1
-1 [amounts of -1] were 547 and 2451 □, respectively.

Upper hip 1 bite 1 ri 16 The same experiment as in experiment W 6 was conducted except that ultrasonic treatment was not performed. Wet layer particulate matter and dry bed wood grains (F
The weight of (2) was 3777.275i.

Comparison 1 J 4 Sample #B of di-2-ethylhexyl phthalate used in Example 1 No. 41! was changed to 40 m17 mjn (approximately 25 parts by weight per 1004j% i part of TFFL fat).
- A An experiment similar to Example 1 was conducted, and a nor-like substance U was obtained. Comparative Example 5 Example 1 An experiment similar to Example 1 was conducted.

The resulting wet granules and dry resin particles (Mm of Ml were 586% and 27,471 ivy, respectively).

Reference Example 1 The same resin aqueous fraction used in the run t<=lli,
The spray dryer is used to dry people [1 temperature 165G, outlet temperature 5
The dried resin was obtained by drying with 5 U and grinding with a tabletop barberizer.

Table 1 shows the properties of the resins (A) to (I).

Claims (1)

[Claims] By adding and mixing an organic liquid that is sparingly soluble in water and does not dissolve or swell the vinyl chloride resin into an aqueous dispersion of vinyl chloride resin, vinyl chloride and A-resin are separated from the aqueous phase as granular aggregates. When recovering the vinyl chloride/L 4nI fat by separating and drying, the mixture of the aqueous dispersion 11 and the organic liquid can be carried out by a combination of ultrasonic treatment in the first stage and means other than ultrasonic wave treatment in the second stage. /I''
A method for recovering vinyl chloride resin as f-ridges.