RU2358994C1 - Method of producing granular plasticised polyvinyl chloride composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: proposed is a method of producing polymers and materials based on polyvinyl chloride, used in different industries, where there is need for materials with low flammability and smoke emission, good chemical resistance, frost resistance and heat resistance. Granular plasticised polyvinyl chloride composition is produced through mixture with plasticisers, stabilisers, fillers and possibly other special additives of polyvinyl chloride with Fikentscher constant C_f=58÷76, obtained using suspension polymerisation method with 0.7÷0.9 monomer conversion, which is a white powder, consisting of porous opaque particles and characterised by specific surface area of S_s=1÷2 m²/g, and value of plasticiser mass absorption α=C_f-(38+46) g/100 PVC. The composition can also contain polyvinyl chloride suspension with Fikentscher constant C_f=35÷46.

EFFECT: obtaining granular plasticised composition with improved processing characteristics, increased harness and homogeneity.

2 cl, 3 tbl, 6 ex

Description

The invention relates to the field of polymer technology, and in particular to a method for producing plasticized polyvinyl chloride compositions for various purposes for the furniture, medical, shoe and cable industries, including for the manufacture of insulation and cable sheaths and wires, which have low combustibility and smoke emission, high frost resistance (to - 65 ° C) and heat resistance (up to + 105 ° C), characterized by increased homogeneity of the material surface (low number of fish eyes).

The widespread use of plastic compounds based on suspension polyvinyl chloride (PVC) is explained by their operational properties, a wide range of compositions used for the manufacture of products, as well as the variety of technological processes used for processing: extrusion, injection molding, calendaring, etc. (“ENCYCLOPEDIA OF POLYMERS,” vol. 1, Moscow: Sov. Encyclopedia, 1972, p. 444).

Plasticized compositions are obtained by mixing suspension PVC of various molecular weights with plasticizers, stabilizers, as well as other processing aids (lubricants, flame retardants, fillers, etc.) in a two-stage mixer with heating above the glass transition temperature of PVCS equal to 80 ° C (usually up to 110-130 ° C for complete absorption of the plasticizer by the polymer), by cooling the resulting dry bulk mixture below the glass transition temperature of PVC (usually to 50-70 ° C), followed by granulating it in single screw or twin screws Ohm extruder. In modern high-performance processes for the production of plasticized PVC materials, the duration of the heating stage of PVCS and additives with a plasticizer (plasticizer absorption time by polymer) is 3-6 minutes (AF Nikolayev. Synthetic polymers and plastics based on them. M: Chemistry, 1964 , pp. 212-215, 220-227).

PVCs for the manufacture of plasticized compositions are obtained in reactors - batch autoclaves with a heat sink. Vinyl chloride with the initiator dissolved in it is mixed in an aqueous medium containing a high molecular weight emulsion stabilizer, followed by heating the mixture to a certain temperature depending on the desired molecular weight of the PVCA. At the end of the process, with the conversion of vinyl chloride p = 0.7-0.9, the non-polymerized monomer - vinyl chloride is removed, the polyvinyl chloride is isolated from the suspension in a centrifuge, the precipitate is dried with hot air to a residual moisture content of 0.3-0.5%, the powder is sieved and packaged. The end of the process of polymerization of vinyl chloride with a monomer conversion of less than p <0.7 leads to a decrease in reactor productivity and, consequently, an increase in the cost of PVCs. With a conversion of more than p> 0.9, glassy PVCS particles with low porosity are obtained, poorly absorbing the plasticizer (see A.F. Nikolayev, pp. 228-232).

The main properties of PVCs, determining the quality of the plasticized composition and manufacturability during processing, are:

- "plasticizer absorption mass" - characterizes the ability of PVC to absorb plasticizer when it is processed into plasticized products;

- "bulk density" - determines the fill factor of the screw of the extrusion machines and their productivity;

- "specific surface" - characterizes the coherence of microglobules in the grain and the strength of the particles of PVC;

- “morphological homogeneity of PVCA powder” - is assessed by its homogeneity - the number of transparent points, the so-called “fish eyes”, in the plasticized PVCA film (see ibid. A.F. Nikolayev, p.248-267).

Currently, in the production of plasticized compositions, various grades of suspension PVC are used with a value of K _f = 58 ÷ 110. Plasticized PVC-based compositions with K _f less than 58 have low physical and mechanical characteristics, which significantly limits their use for the manufacture of products for various purposes.

The main parameters affecting the process of plasticizer absorption are porosity and specific surface area of PVCA grain. Commercially available PVCs (ε = 0.20-0.25 cm ³ / g, S _beats = 0.5-1 m ² / g) are heterogeneous and contain both porous (opaque) and non-porous (glassy) particles that absorb plasticizer with different speeds, which leads to the appearance of "fish eyes" both during extrusion processing and upon receipt of various films by calendering. Porosity determines the ability of a polymer to absorb plasticizer and is related to the indicator "plasticizer absorption mass" by the dependence (V. M. Ulyanov, E. P. Rybkin, A. D. Gutkovich, G. A. Pishin. Polyvinyl chloride. M .: Chemistry, 1992, p.53)

ε = α / (70 + α),

where ε is the porosity of PVCA,

α is the mass of absorption of the plasticizer, g / 100 g of PVC.

There are a large number of patents for the production of PVCs used in industry, as well as prescription techniques for producing highly porous polymers to reduce the number of fish eyes.

For example, in US patent No. 5155189, C08F 2/20, publ. 13.10.92, PVCA is described with K _f = 69 with a porosity of 0.342 cm ³ / g and a plasticizer absorption time of 297 s, obtained by polymerization in the presence of dispersants (first and second); the second dispersant is a derivative of esters of acrylic and / or methacrylic acids and containing terminal functional groups (carboxyl, hydroxyl, anhydride, alkyd, amine, isocyanate); the first dispersant is hydrolyzed polyvinyl alcohol, gelatin, cellulose, cellulose ether. The resulting polymer is characterized by a low rate of the number of fish eyes. The disadvantage of this polymer is the low bulk density and conversion of the monomer upon receipt (p = 0.5-0.8), which makes its use expensive and low-tech.

In another patent (US Patent No. 5,342,906, C08F 2/20, publ. 30.08.94), PVCs are obtained with K _f = 67 with a bulk density of 0.56 g / cm ³ , porosity of 24.5% by suspension polymerization of vinyl chloride in an aqueous medium, in the presence of a dispersing agent (polyvinyl alcohol) and an initiator soluble in the monomer; with vigorous stirring and heating. The resulting material has an increased surface homogeneity (1 fisheye per 100 cm ² film), but the conversion of the monomer upon receipt is 0.6-0.7, which makes its use quite expensive.

Known patents that use PVCA with a high Fikentcher constant K _f . So, PVCA with a Fikentcher constant 80-110 with a bulk density of 0.2-0.35 g / cm ³ (RF patent No. 2085563, C08L 27/06, publ. 07.27.97) is used in polymer compositions from PVCA as a modifier for improving the physical and mechanical properties of products. The disadvantage of this PVCA is the low bulk density and, accordingly, poor flowability, which makes it suitable only as a modifier.

In the patent of the Russian Federation No. 2249020, C08L 27/06, publ. 03/27/05, the authors use PVCA with K _f = 80-110 and a bulk density of 0.20-0.55 g / cm ³ in the polymer composition to obtain a miplastic separator. PVCA is used as an additive to emulsion PVC, in an amount of 5-15 wt.%, In order to increase the volumetric porosity of the separator, reduce electrical resistance while maintaining tensile strength and increase the performance of the tape sintering machine. PVCA with K _f = 80 ÷ 110 receive suspension polymerization of vinyl chloride in a reactor with a volume of V = 17 m ³ . 8700 kg of demineralized water, a dispersion stabilizer (methylhydroxypropyl cellulose or polyvinyl alcohol), the initiator is dicetyl peroxydicarbonate, an alkaline agent (sodium hydroxide or sodium bicarbonate) are charged into the reactor with an impeller mixer and a heat transfer jacket, 0.025 ÷ 0.06 wt.% To water and 5400 kg vinyl chloride. The coolant (water) is supplied to the reactor jacket. The process is carried out at a temperature of 32 ÷ 43 ° C for 6-12 hours. Unreacted vinyl chloride is removed from the reactor, the polymer is filtered and dried. A finely dispersed polymer K _Ф = 80 ÷ 110 and a bulk density of 0.20 ÷ 0.55 g / cm ³ determined according to GOST 11035.1-93 are obtained. In a polymer with a specified range of bulk density of 0.2-0.55 g / cm ^{2 the} presence of both porous and non-porous particles of PVCA is possible, which, as shown above, affects the processing of the polymer into products.

However, a single value of porosity is not enough to characterize the internal structure of PVCA particles, since porosity characterizes only the volume of voids in the polymer particle. Another important characteristic of the porous structure of PVCA particles is the specific surface area. When processed into plasticized products, the developed specific surface allows the plasticizer to be quickly and evenly absorbed.

The value of the specific surface of the polymer is determined by the method of thermal desorption of argon (Keltsev N.V. Fundamentals of adsorption technology, 2nd ed., Revised and additional M .: Chemistry, 1984, p. 47).

In the patent of the Russian Federation No. 2275383, C08F 14/00, publ. 04/27/2006, bull. No. 12, the authors propose PVCs characterized by porosity values of 0.27-0.42 cm ³ / g and a specific surface area of 1.0-4.0 m ² / g, which has high morphological homogeneity (the absence of glassy non-porous particles) and good flowability. PVCA is obtained in a reactor with a volume of 17 m ³ with a mixing device and a heat transfer jacket. 8700 kg of the aqueous phase, 5400 kg of vinyl chloride and 0.2 wt.% (To vinyl chloride) of dicetyl peroxydicarbonate are charged as a peroxide initiator. The aqueous phase contains 0.05 wt.% (To water) polyvinyl alcohols as a dispersion stabilizer, 0.015 wt.% (To water) sodium hydrogen carbonate as a pH regulator and 0.01 wt.% (To water) 4-methyl- 2,6-ditretic butylphenol as an antioxidant. A coolant (water) with a temperature of 80 ° C is supplied to the reactor jacket and the contents of the reactor are heated to a polymerization temperature of 40 ° C. The polymerization process is carried out at a polymerization temperature of 40 ° C and is completed when the pressure in the reactor drops by 1.5 ati from the regime. The polymerization process takes 8 hours. The number of revolutions of the mixer during the entire polymerization process n = 3 s ^-1 . The impeller mixer, the diameter of the mixer d = 0.9 m. Upon receipt of this polymer, the monomer conversion is p = 0.5-0.7, which, along with a high specific surface area and porosity, leads to a decrease in the bulk density of the material, thereby reducing processability polymer during processing.

The disadvantages of PVC with K _f = 77-110 should also include:

1. When processing compositions based on PVC with K _f = 77-110, high temperatures are required, which on existing equipment is of considerable complexity.

2. To obtain PVCA with a constant K _{f of} more than 89, special expensive low-temperature polymerization initiators and (or) bifunctional comonomers are required, which leads to a sharp rise in the price of PVCS.

Due to these two factors, PVCA with a value of K _f = 77-110 is usually used in industry only as a functional additive to the main PVCA with a constant K _f = 58-76.

The closest in technical essence of the invention is PVCA with K _f = 71, a well-absorbing plasticizer due to its high porosity (US Patent No. 5286796, C08F, publ. 15.02.94). The polymer is obtained by water-suspension polymerization of vinyl chloride using (a) polyvinyl acetate with a saponification degree of 75 to 99% and an average degree of polymerization of 1500-2700 and (or) (b) hydroxypropyl methylcellulose with a degree of substitution by methyl groups of 26-30% and hydroxypropyl groups of 4 -15% with a viscosity of 2% aqueous solution at 20 ° C in the range from 5 to 4000 cP, as well as (c) from 0.002 to 0.2 wt.h. (per 100 parts by weight of vinyl chloride) of water-insoluble polyvinyl acetate with a degree of saponification of 20-60% and a degree of polymerization from 2000-30000. The polymerization is carried out at a temperature of 51 ° C and stirring and complete when the pressure in the reactor drops to 5.0 ati. The residual vinyl chloride is then blown off, the polymer is dried and dried. Get PVCA with a constant K _f = 71, bulk density 0.50-0.52 g / cm ³ , the mass of absorption of the plasticizer 34-36%. This polymer is notable for its high porosity and specific surface area, which during the high-speed process of mixing PVCA with plasticizer and additives leads to poor flowability of the composition and to obtain an increased content of fish eyes in the film due to the uneven absorption of the plasticizer by PVCA particles.

When the value of the specific surface area S _beats = 1 ÷ 2 m ² / g, the resulting PVCA is morphologically homogeneous and technological, however, as can be seen from the above patents, the optimal porosity values are not established to ensure a high level of homogeneity of the surface of the PVC material depending on the molecular the mass of PVCA used, which leads to an unreasonable increase in the porosity of PVCA, leading to an increase in prices and a decrease in the processability of the polymer.

The authors of the present invention determined for PVCs the ratio of the optimal values of porosity and the value of the Fikentcher constant K _f as K _f - (38 ÷ 46), providing a high level of homogeneity of the surface of the PVC material.

When the plasticizer absorption mass is less than K _f -46, the plasticizer does not have time to completely absorb the polymer when mixed, which leads to the appearance of inhomogeneities and defects during processing into plasticized products.

With a plasticizer absorption mass greater than K _f -38, PVCS in a mixture with plasticizers and additives has a low bulk density, poor flowability and becomes non-technological. In addition, with a very high porosity, difficulties arise in the uniform distribution of the plasticizer in the polymer, since the bulk of the polymer can absorb all the plasticizer introduced into the composition, while some polymer particles will remain without the plasticizer.

With a specific surface area of less than 1.0 m ² / g, the polymer is morphologically heterogeneous, does not absorb plasticizer fast enough, which leads to defects during processing into plasticized products, and with a specific surface area of more than 2.0 m ² / g, the polymer has a low bulk density, poor flowability and becomes non-technological.

An object of the invention is to increase the level of homogeneity of the surface of the PVC composition, as well as improving manufacturability along with improving the hardness of plasticized PVC composition.

The object is achieved by the method of producing a granular plasticized composition based on polyvinyl chloride by mixing polyvinyl chloride with at least one plasticizer, one stabilizer, filler and possibly other technological target additives in the mixer and subsequent granulation of the composition in a screw extruder, with polyvinyl chloride being used as a constant with polyvinyl chloride Ficentcher K _f = 58 ÷ 76, obtained by suspension polymerization during the conversion of monomer 0.7 ÷ 0.9 and p it is a white powder, consisting of porous opaque particles, characterized by a specific surface area S _beats = 1 ÷ 2 m ² / g and a plasticizer absorption mass α = K _f - (38 ÷ 46) g / 100 g PVC.

In addition, the task is also achieved by the fact that suspension polyvinyl chloride with K _f = 35 ÷ 46 in the amount of 1-5% of the total mass of polyvinyl chloride is additionally added (added) to the composition, which helps to increase hardness and improve the processability of PVC compound.

So, the task is achieved by obtaining a plasticized composition by mixing PVCA with the Fikentcher constant K _f = 58 ÷ 76, obtained by suspension polymerization during the conversion of monomer 0.7 ÷ 0.9, which is a white powder and consisting of porous opaque particles characterized by a value specific surface S _beats = 1 ÷ 2

m ² / g and the absorption mass of plasticizer α, depending on the value of K _f and determined by the formula α = K _f - (38 ÷ 46), in a two-stage mixer with a mixer speed of 500-800 rpm with plasticizers (for example, dioctyl phthalate, dioctyl sebacinate , chloroparaffin, etc.), stabilizers (tribasic lead sulfate, dibasic lead phthalate, complex calcium-zinc, etc.), fillers (chalk, kaolin, etc.) and other technological target additives (lubricants, dyes, etc.) during 3-6 minutes and subsequent granulation in an extruder temperature in zones 110-190 ° С. The following examples illustrate the invention, but do not limit it.

Example 1. In a reactor of 17 m ³ with a stirrer and a heat transfer jacket, 8700 kg of the aqueous phase, 5400 kg of vinyl chloride and 0.1 wt.% (To vinyl chloride) of dicetyl peroxydicarbonate are loaded as a peroxide initiator. The aqueous phase contains 0.05 wt.% (To water) polyvinyl alcohols as a dispersion stabilizer, 0.015 wt.% (To water) sodium hydrogen carbonate as a pH regulator and 0.01 wt.% (To water) 4-methyl 2 , 6-ditretic butylphenol as an antioxidant. A coolant (water) with a temperature of 80 ° C is supplied to the reactor jacket and the contents of the reactor are heated to a polymerization temperature of 62 ° C. The polymerization process is carried out at a polymerization temperature of 62 ° C and is terminated when the pressure in the reactor drops by 1.5 atm from the regimen monomer conversion p = 0.85. The number of revolutions of the mixer during the entire polymerization process n = 3 s ^-1 . Impeller stirrer, diameter of stirrer d = 0.9 m.

The specific surface area was measured by thermal desorption of argon using a sorbtometer. Obtained in example 1 PVCA fully complies with GOST 14332-78, including in terms of:

Fikentcher constant - K _f = 63,

plasticizer absorption mass - α = 18 g / 100 g PVCA,

the residue after sifting on sieve No. 0063 - 96%,

specific surface area is 1.4 m ² / g.

To obtain a plasticized composition in the hot chamber of a two-stage mixer load the obtained PVCA - 100 wt.h. (125 kg), calcium stearate - 2 parts by weight (2.5 kg, TU 6-09-4104-85), stirred at a speed of the mixer n = 800 rpm with self-heating of the mixture to 70 ° C, dioctyl phthalate - 45 wt.h. (56.25 kg, GOST 8728-27) with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

Granulation of the resulting mixture is carried out in a twin-screw extruder at temperatures in the zones 1 - 135 ° C, 2 - 145 ° C, 3 - 155 ° C, head - 165 ° C.

Example 2. In the reactor with a volume of 17 m ³ with a mixing device and a heat transfer jacket, 8700 kg of the aqueous phase, 5400 kg of vinyl chloride and 0.13 wt.% (To vinyl chloride) of dicetyl peroxydicarbonate are charged as peroxide initiator. The aqueous phase contains 0.075 wt.% (To water) polyvinyl alcohols as a dispersion stabilizer, 0.015 wt.% (To water) sodium hydrogen carbonate as a pH regulator and 0.01 wt.% (To water) 4-methyl 2.6 D-tertiary butylphenol as an antioxidant. A coolant (water) with a temperature of 80 ° C is supplied to the reactor jacket and the contents of the reactor are heated to a polymerization temperature of 51 ° C. The polymerization process is carried out at a polymerization temperature of 51 ° C and is completed when the pressure in the reactor drops by 1.5 atm from the regimen monomer conversion p = 0.79. The number of revolutions of the mixer during the entire polymerization process n = 3 s ^-1 . Impeller stirrer, diameter of stirrer d = 0.9 m.

The specific surface area was measured by thermal desorption of argon using a sorbtometer. Obtained in example 2 PVCA fully complies with GOST 14332-78, including in terms of:

Fikentcher constant - K _f = 71,

plasticizer absorption mass - α = 29 g / 100 g PVCA,

the residue after sifting on sieve No. 0063 - 96%,

specific surface area - 1.8 m ² / g.

To obtain a plasticized composition, the resulting PVCA is loaded into a hot chamber of a two-stage mixer - 125 kg, calcium stearate - 2.5 kg (TU 6-09-4104-85), mixed at a stirrer speed n = 800 rpm with self-heating of the mixture up to 70 ° C, add dioctyl phthalate (GOST 8728-27) - 56.25 kg with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

Granulation of the resulting mixture is carried out in a twin-screw extruder at temperatures in the zones 1 - 140 ° C, 2 - 150 ° C, 3 - 160 ° C, head - 170 ° C.

Comparison of plasticized compositions by homogeneity (the number of fish eyes) was carried out according to the following method GOST 14332-78. To the finished mixtures obtained on the basis of various samples of PVCA according to the claimed method and taken for comparison, on the basis of commercially available PVCA grades S6359M, S7059M, 0.15-0.30 wt.h. carbon black brand P-234 (GOST 7885), thoroughly mixed and rolled on rollers with electric heating with a roll diameter of 200 mm, a work surface length of 450 mm, and a front roll speed of 20

min ^-1 , friction 1, two films 0.2 ± 0.02 mm thick for 5 min from the moment of loading the composition, cutting the film 9-10 times, at the temperature indicated in table 1. The temperature was measured in the central part of the roll with a thermal kit with an error of not more than 2 ° C. The resulting film was placed on frosted glass with illumination carried out at a distance of 100 mm by a 40 W lamp, and the number of fish eyes in 100 cm ^{2 of the} film was counted. The results of the tests are presented in table 2.

Table 1 The rolling conditions of the plasticized composition (GOST 14332-78) The value of K _f Rolling temperature, ° С Front roll Rear roll 63 143 ± 2 140 ± 2 71 153 ± 2 150 ± 2

table 2 Compositions and comparative properties of plasticized compositions Composition components The composition, wt.h. Example 1 Serial Example 2 Serial PVCA, K _f = 63 one hundred PVCS S6359M one hundred PVCA, K _f = 71 one hundred PVCS S7059M one hundred Dioctyl phthalate 45 45 45 45 Calcium stearate 2 2 2 2 Soot 0.2 0.2 0.2 0.2 The number of transparent dots ("fish eyes") in 100 cm ² film, pcs. four 12 5 10

The number of fish eyes, which determines the homogeneity of the surface, is one of the main indicators of the quality of PVC compound.

Thus, from the above examples, it follows that the method of producing a granular plasticized composition according to the invention, which consists in mixing PVCA with plasticizers, stabilizers, fillers and other possible target additives in a mixer, followed by granulating the composition in a screw extruder using polyvinyl chloride with a Fikentcher constant K _f = 58 ÷ 76 obtained by the method of suspension polymerization during the conversion of monomer 0.7 ÷ 0.9, which is a white powder, consisting of porous of opaque particles, characterized by a specific surface area S _beats = 1 ÷ 2 m ² / g and a plasticizer absorption mass α = K _f - (38 ÷ 46) g / 100 g PVCA, leads to an improvement in the quality (uniformity) of the surface of granular PVC- material and improved processability in processing.

Plasticized PVCS compositions are used to produce a wide range of plasticized products. The value of the melt flow rate (MFR), which characterizes the flow rate of the molten thermoplastic through a standard size capillary at a given temperature and pressure, is a parameter that determines the processability of the polymer and the method of its processing. The flow rate is expressed in grams of polymer extruded over a standard time (10 min). The higher the melt flow rate of the plasticized composition, the lower its viscosity and the higher the processing speed — better processability.

Another important indicator characterizing the quality of the plasticized composition is its hardness. The higher the hardness of the plasticized composition, the better the wear resistance of products based on it and other mechanical properties of the surface.

The main way to improve the manufacturability of plasticized PVC composition (increase PTR) is to add an additional amount of plasticizer. However, an increase in the content of plasticizer in the system leads to a decrease in the hardness of the plasticized composition and a decrease in the wear resistance of products based on it. The use of various kinds of lubricants leads to an increase in the melt flow rate of the plasticized composition, but does not increase its hardness.

The addition of low molecular weight PVCA leads to an increase in the hardness and MFI of the plasticized composition. However, the production of PVCA with K _f <35 proceeds at extremely high pressure, which requires the use of reactors of a special design and makes the process of producing PVCA with K _f <35 impossible under the conditions of the existing industrial production in Russia. The introduction into the composition of the plasticized PVC composition of suspension PVC with K _f more than 46 leads to a decrease in the MFI composition, however, the effect of increasing hardness is practically absent. When the content in the plasticized composition is less than 1% of low molecular weight PVCA, there is no significant increase in the hardness of the PVC material, and its concentration of more than 5% of the total mass of PVCA leads to a deterioration in the physicomechanical characteristics of the plasticized composition.

Another technical objective of the invention is to increase manufacturability along with improving the hardness of plasticized PVC composition. This problem is achieved by introducing into PVCS suspension PVC with a Fikentcher constant K _f = 35-46 in an amount of 1-5% of the total weight of PVCS.

A comparison was made of the hardness and PTR of PVCS materials based on K _f = 63, K _f = 71 (examples 1, 2). As an ester plasticizer - phthalic acid esters - dioctyl phthalate (DOP) GOST 8728-27. As a metal-containing stabilizer, the composition contains tribasic lead sulfate (TOSS TU 6-09-4098-75) and calcium stearate (StSa), TU 6-09-4104-85, as a lubricant stearin, GOST 6484-64.

Example 3. To obtain a plasticized composition in the hot chamber of a two-stage mixer load the resulting PVCA - 125 kg; 3.75 kg of tribasic lead sulfate; 1.88 kg of calcium stearate; 0.38 kg of stearin; 1.25 kg of PVCA with K _f = 35, stirred at a stirrer speed of n = 800 rpm with self-heating of the mixture to 70 ° C, dioctyl phthalate - 100 kg was added with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

Granulation of the resulting mixture is carried out in a twin-screw extruder at temperatures in the zones 1 - 120 ° C, 2 - 130 ° C, 3 - 140 ° C, head - 145 ° C. From the obtained plastic compound on laboratory rolls VDE - 320-160 / 160, at a temperature of the work roll of 141 ° C and a temperature of the idle roll of 138 ° C, a film 1 ± 0.1 mm thick is rolled. Then, from the obtained film, in a hydraulic press in accordance with GOST 24621-81, plates of PVC material with dimensions 100 × 100 × 6 mm are pressed, they are conditioned (GOST 12423-66). Shore hardness “A” values are measured on each sample after 15 ± 1 seconds at least 3 times on an IT-5078 instrument.

To determine the melt flow rate of the composition, the obtained granules were selected, conditioned (GOST 2423-66), then, in accordance with GOST 11645-73, on the IIRT-5 device at a temperature of 170 ° C and a piston load of 5 kg, the melt flow rate was measured.

Example 4. To obtain a plasticized composition in the hot chamber of a two-stage mixer load obtained in example 1 PVCA - 125 kg; 3.75 kg of tribasic lead sulfate; 1.88 kg of calcium stearate; 0.38 kg of stearin; 6.25 kg of PVCA with K _f = 35, stirred at a stirrer speed of n = 800 rpm with self-heating of the mixture up to 70 ° C, dioctyl phthalate - 100 kg was added with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

The methods and modes of granulation, obtaining samples, measuring the hardness index and PTR of the plasticized composition are similar to example 3.

Example 5. To obtain a plasticized composition in the hot chamber of a two-stage mixer load obtained in example 2 PVCA (K _f = 71) -125 kg; 3.75 kg of tribasic lead sulfate; 1.88 kg of calcium stearate; 0.38 kg of stearin; 1.25 kg of PVCA with K _f = 46, stirred at a stirrer speed n = 800 rpm with self-heating of the mixture up to 70 ° C, dioctyl phthalate - 100 kg was added with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

Granulation of the resulting mixture is carried out in a twin-screw extruder at temperatures in the zones 1 - 123 ° C, 2 - 133 ° C, 3 - 143 ° C, head - 155 ° C. From the obtained plastic compound on laboratory rolls VDE - 320-160 / 160, at a temperature of the work roll of 150 ° C and a temperature of the idle roll - 148 ° C, a film 1 ± 0.1 mm thick is rolled. Then, from the obtained film, in a hydraulic press in accordance with GOST 24621-81, plates of PVC material with dimensions 100 × 100 × 6 mm are pressed, and they are conditioned (GOST 12423-66). Shore hardness “A” values are measured on each sample after 15 ± 1 seconds at least 3 times on an IT-5078 instrument.

To determine the melt flow rate of the composition, the obtained granules were selected, conditioned (GOST 12423-66), then, in accordance with GOST 11645-73, on the IIRT-5 instrument at a temperature of 170 ° C and a piston load of 5 kg, the melt flow rate was measured.

Example 6. To obtain a plasticized composition in the hot chamber of a two-stage mixer load obtained in example 2 PVCA (K _f = 71) -125 kg; 3.75 kg of tribasic lead sulfate; 1.88 kg of calcium stearate; 0.38 kg of stearin; 6.25 kg of PVCA with K _f = 46, stirred at a stirrer speed n = 800 rpm with self-heating of the mixture up to 70 ° C, dioctyl phthalate - 100 kg was added with further self-heating to 115 ° C for 4 minutes. When this temperature is reached, the mixture is discharged into the cold chamber of the water-cooled mixer. When cooling the mixture to 50 ° C, the mixture is unloaded from the mixer.

The methods and modes of granulation, obtaining samples, measuring the hardness index and PTR of the plasticized composition are similar to example 5.

The results of the tests are presented in table 3.

Table 3 Compositions and comparative properties of plasticized compositions Composition components The composition, wt.h. PVCA, K _f = 63 one hundred - one hundred one hundred - - PVCA, K _f = 71 - one hundred - - one hundred one hundred PVCA, K _f = 35 - - one 5 - - PVCA, K _f = 46 - - - - one 5 Dioctyl phthalate 80 80 80 80 80 80 Tribasic Lead Sulfate 3 3 3 3 3 3 Calcium stearate 1,5 1,5 1,5 1,5 1,5 1,5 Stearin 0.3 0.3 0.3 0.3 0.3 0.3 Shore A hardness 57 59 59 61 61 63 PTR, g / 10 min 21 4.8 21.5 22 5.2 5.5

Hardness and melt flow rate are some of the main indicators characterizing the quality of the plasticized composition based on PVC. As can be seen from table 3, the values of these indicators are always higher when the content in the composition of PVCA with K _f = (35 ÷ 46) in an amount of 1 ÷ 5% of the total weight of PVCA.

Thus, the above data indicate that the introduction of suspension polyvinyl chloride with a Fikentcher constant K _f = (35 ÷ 46) in an amount of 1 ÷ 5% of the total mass leads to an increase in hardness and an improvement in the manufacturability of the plasticized composition based on PVC.

Claims (2)

1. A method of producing a granular plasticized composition based on polyvinyl chloride, which consists in mixing polyvinyl chloride with plasticizers, stabilizers, fillers and possibly other technological target additives in a mixer, followed by granulating the composition in a screw extruder, characterized in that polyvinyl chloride is used with Fikentcher constant K _f = 58 ÷ 76, obtained by suspension polymerization during the conversion of monomer 0.7 ÷ 0.9, which is a white powder, consisting of Risto opaque particles, characterized by a specific surface area S _ud = 1 ÷ 2 m ² / g and the amount of plasticizer absorption mass α = K ₌ - (38 ÷ 46) g / 100 g of PVC. 2. A method for producing a granular plasticized composition according to claim 1, characterized in that, in order to increase hardness and improve the processability of the polyvinyl chloride plasticate, suspension polyvinyl chloride with a Fikentcher constant K _f = 35 ÷ 46 in an amount of 1 ÷ 5% of the total weight of polyvinyl chloride is additionally introduced into the composition.