SU680653A3 - Method of processing powderlike pvc - Google Patents

Description

with the advantage of the dry polymerization method, i.e. the possibility of separating water by filtration and / or drying. In addition, it is obvious that this method can only produce polymers with a residual monomer content of vinyl chloride above 0.01 wt.%, Which according to new data does not meet the requirements of physiologically harmless polyvinylchloride 1 dal (limit of vinyl chloride is 0.001 wt.% Or less) The aim of the invention is to reduce the content of residual monomer in polyvinyl chloride. This goal is achieved by the fact that in the process of treating powdered polyvinyl chloride containing 0-100 wt.% Of polymerized vinyl chloride units, after removing the main amount of unreacted vinyl chloride monomer or unreacted copolymers, polyvinyl chloride is heated under pressure of 56 to 566 ° C. The treatment is carried out for 10360 minutes, at 75-120 ° C, in the presence of 0.01-5 wt.% (Counting, on the polymer, an aliphatic, saturated or unsaturated, branched or unbranched compound containing two hydroxyl groups and 2-24 carbon atom, and in the case of 4 or more carbon atoms, may also contain 1-11 С-О-С groups. Heat treatment can be carried out at atmospheric or reduced pressure. It is advisable to work at a pressure of 50-760 mm Hg, especially at atmospheric pressure. Heat treatment is carried out for 10-360 minutes at temperature 75.-120s. At the same time, one or several inert gases, for example air or nitrogen and water vapor, are passed through the vessel in which the treatment is carried out. Of the two gases, for example air and nitrogen, air is more commonly used. The concentration of monomeric vinyl chloride in The polymer decreases with increasing temperature and processing time. When processed for less than 10 minutes, the content of residual monomer does not noticeably decrease. At higher temperatures and after longer treatments, the polymer becomes darker. This is especially noticeable in the thermoplastic processing of such polymers, when darker products are received more rapidly than they should. When heat treatment is carried out in the presence of a compound with two free hydroxyl groups and 24 carbon atoms, it is possible to significantly increase the temperature and duration of the treatment. The proposed method has practically no 4 advantages when processing popimerate zat at a temperature above and a duration of more than 360 minutes, since under these conditions there is a dramatic change in grain and darkening. Especially good results are obtained at a temperature of VO-SO with. It is advisable to conduct heat treatment so that the product of the treatment temperature (° C) and the processing time (hours) would be 25-350 (° C-h), especially 50-U60 (° C-h). Heat treatment is carried out in the presence of 0.01-5% by weight (calculated on a dry polymer) of at least one aliphatic saturated or not: Saturated, branched or unbranched compound with 2 free hydroxyl groups and 2-24 carbon atoms, which in the case of 4 and more than carbon atoms may also contain at least one C-O-C group. With the addition of 0.01 wt.% Of this compound, no effect is observed, and with additives of more than 0.5 wt.%, The flowability of the polymer powder deteriorates, the heat resistance and transparency of the products obtained from the polymer decrease, and adhesion to the parts of the processing machine occurs. . The optimum amount of this compound is 0.2-2% by weight, in particular 0.51.5% by weight (calculated on dry polymer). These compounds can be added to the reaction mixture before or during the polymerization of vinyl chloride or after polymerization to the final polymerizate before heat treatment. In order to better distribute the proposed compound in the final polymerizate, it can be broken up with easily volatile solvents, such as water, and added in a diluted form. Strong dilution with water should be avoided, since in the presence of large amounts of water, starting with 5 Ae.% (Counting on the polymer), the effect according to the invention also decreases with increasing amount of water, darkening is enhanced. Using the invention according to the invention, the compounds may contain c-O-C groups, i.e. ether-oxygen bridges. Good results are obtained when using compounds of the formula OH (OH 2 - CHX 0) “H, where XH and / or CH z n 1-12. According to the invention, it is particularly suitable for the treatment of diglycopne polymerizate or triglycol or a mixture of diglyx and triglycol. Along with these aliphatic saturated compounds with ether-oxygen bridges, good results are also obtained if the heat treatment is carried out in the presence of aliphatic, saturated or unsaturated, branched or unbranched compounds with two free hydroxyl groups and 3-12 carbon atoms. As examples of such compounds, propandiol-1,3, butanediol-1,4, hexanediol-1, b pentandial-1,5, hexanediol-2.5, decanediol-1, 10 can be mentioned. Especially good results are obtained with butene-2-diol-1, 4.

According to the invention, it is possible to use both individual substances and mixtures of several of these substances.

 The addition of these substances before or during the polymerization does not have a noticeable effect on the quantity and properties of the powder of the polymerization product obtained and all the substances usually necessary for the polymerization can be used together with the substances of the invention.

According to the invention, for processing, dry homopolymers, copolymers and grafted hovinil popimerizates containing not less than 80 weight polymerized units of vinyl chloride and obtained by the emulsion and suspension polymerization method are processed. Preferred polymers are obtained in the gas phase, and especially those obtained by the method of mass polymerization at a temperature of 30–3.3 ° C. All of the above polymerization methods can be carried out both continuously and periodically.

For copolymerisation with vinyl chloride, you can use, for example, one or more monomers such as olefins, for example ethylene or propylene, vinyl ethers of carboxylic acids with linear or branched chains with carbon numbers 2-20, preferably 2-4, for example vinyl acetate-, propionate , butyrate-, 2-ethylhexoate, tridecanoic acid vinyl ester, vinyl gadogenide, for example, vinylidene fluoride fluoride, vinylidene chloride, vinyl ether, vkiylpyridine, unsaturated acids, for example maleic, fumaric, acrylic, m etacrylic and their mono- or diesters with alcohols or glycols with 1-10 carbon atoms, Mscheic acid anhydride, maleic acid amine, as well as their substituted products with aromatic, cycloaliphatic, and branched isyphatic substituents, acrylonitrile, styrene

For graft polymerization, it is possible, for example, to apply elastomeric polymers obtained by polymerizing one or more

the following monomers: dienes, for example butadiene, cyclopentadiene, olefins, for example ethylene, propylene; unsaturated acids, such as acrylic or methacrylic, and their esters with alcohols and glycols, 5 containing 1-10 carbon atoms, acrylonitrile, vinyl compounds, such as vinyl ethers of linear or branched carboxylic acids containing 2-20 carbon atoms,

0 preferably 2-4, vinyl halides, for example vinyl chloride, vinylidene chloride.

After polymerization, the resulting polymers can be added

5 known excipients

to stabilize or improve processability.

For treating polyvinyl chloride according to the invention, it may contain

0 to 20% by weight (based on the total substance) of compounds that are not polymerized vinyl chloride. Such compounds can be, for example, toughness modifiers,

5 flow improvers

and / or processability and / or. heat resistance, as well as pigments.

Heat treatment is carried out in the presence of one or several

0 inert gases, such as air, nitrogen, or water vapor.

In order to achieve close contact of both phases, during heat treatment, it is advisable that the polymer powder and / or gas phase be

5 would be in motion. Mechanical or pneumatic means are suitable for this, for example, intermixing, vortexing, dripping, spraying of powder in the gas space.

0

and gas can be given

greater speed than that of solid particles, so that the gas penetrates through a more or less loose layer of powder, preferably from the bottom up.

The treatment according to the invention may

carry out, for example, in a polymerization vessel, after removing the main amount of the liquid or gaseous phase in one or more after ;;

devices, such as vertical flow tubes, a & one-way mixer equipped with blades, in a rotating tube, or a cyclone,

the gas and the polymer must be continuously circulated. It is advisable to device with a tangential gas year in several floors one above the other or the use of boiling

or current slo.

The method according to the invention allows polymers of vinyl chloride, especially those obtained by the method of mass polymerization at a temperature of 3085 ° C, to be subjected to intensive heat treatment required to remove harmful residual monomeric vinyl chloride without darkening of the material, which degrades further applicability. The properties of the treated polymerizer do not deteriorate in comparison with the untreated ones. The method can be led continuously. The temperature can be set optimally, it provides intensive but sparing processing. Treatment facilities are comparatively pro. You are durable and do not require a lot of space for installation. Most minimal: It is the capital cost of processing the jB polymerization vessel. t Shown in the examples, the measurement values of K obtained according to DIN 53726 solvent cyclohexanone. The residual monomer content (vinyl chloride in polyvinyl chloride) was determined by gas chromatographic method. The darkening test was performed on samples of the composition, parts by weight: Polyvinyl chloride 100 Dioctyl tin and ethyl ethylhexyl ether of thioacetic acid 1.5 Slip mixture, which consists of hardened castor oil, triglyceride and monoglycyride (sold under the name L (xiol CH4), triglyceride and monoglycyride (sold under the name L (xiol CH4), triglyceride and monoglycyride (sold under the name L) (xiol CH4) ester of montanoic acid 0.3, Components are extracted without heating with vigorous stirring and 300 g of this mixture is processed for 3 minutes when heated on laboratory rollers into a sheet with a thickness of 3 mm. Technical data: Roll diameter 150 mm rotational speed 11 rpm Roll temperature After cooling, the sheet is cut into rectangular pieces 10x12 cm in size. Twelve such pieces are inserted into a mold with internal dimensions 11x12.5 cm on a heated plate to the press plate. Under low pressure, the pieces are heated 3, 5 min., Then, in the process O, .5 min. They give a total pressure of 40 N / cm, then after 4 min the pieces under pressure are cooled with water to room temperature, the pressure is sauced, the pressed plates are removed from the phorium and by visual comparison of the edges of the plates with bright numbers Then, the color index on a scale of five points is determined by the white surface. Score 1 - color as the standard standard (as a rule, slightly yellow) Score 2 - slight darkening (yellowish) Score 3 - clear darkening (saturated yellow or reddish yellow) Score 4 - severe darkening (color from brownish yellow to orange -Yellow) Score 5 - very strong darkening (light brown or orange-red). As a standard, polyvinyl chloride with K-57 value, which is obtained by polymerization in the mass, is obtained as a standard, obtained after polymerization without subsequent heat treatment with residual vinyl chloride content 1% by weight, based on polymer; Example 1. 10 kg of vinyl chloride homopolymerizate obtained by bulk polymerization at 69 ° C, having a value of K-57, residual vinyl chloride content of 1% by weight (counting on polymer) are mixed in a mixer 3 Fln a mixture of 100 g of diglycol and 500 g of water was allowed to stand for 3 hours while in a ventilated oven, cooled, and 10093 g of polymerizate was obtained.The powder obtained after the heat treatment was dissolved in tetrahydrofuran and subjected to a silylation reaction with bistrimethylsilyl trifluoroacetamide, after which the polymer precipitated of methanol and the mixture solution of tetrahydrofuran: methanol was analyzed by gas chromatography. At the same time, the silylation product of diglycol cannot be detected. According to gas chromatographic analysis, the residual vinyl chloride content is 7 ppm of dry polymerizate. The darkening test gave a score of 1.5. For a better comparison, the values are given in the table. Comparative Experience A. Work as in Example 1 using the same mass polymerizate, but diglycol-water ae mixtures are added. The obtained values are given in the table. Comparative experiment B: Work as in Example 1 using the same mass polymerizate, but only 500 g of water without iglycol is added to 100 kg of polymerizate. Comparative experiment C. They work according to Example 1 using the same mass polymerizate, but instead of a mixture of diglycol and water, a mixture of 100 g of phenol and 500 g of water is added to 100 kg of polymerization. The obtained values are given in the table. Example 2. Polyvinyl chloride is produced by two-step polymerization, with 1 wt.% Diglycate added before the main polymerization stage (2-step), counting on the entire vinyl chloride in 2 steps, and polymerization is carried out at 62 ° C. the action of dilution (degassing) to 50 mm Hg. to remove the majority of the unreacted vinyl chloride monomer. After this treatment, the polymerizate contains another 0.2% by weight of monomeric vinyl chloride and has a value of K-B0.10 kg of the polymer thus obtained is subjected to heat treatment in a drying cabinet at normal pressure for 300 minutes and then oh: limp. The obtained values are given in the table. Examples 3-5. The operation of the wire is as in example 1, however, different amounts of the mixture glyglycol-water are added to the polymerizate; in example 1: 400 g diglycol and 1000 g water; in example 2 10 g diglycol and 100 g water; in approx 3: 5 g diglycol and 100 g water. Example 10 kg of polyvinyl chloride obtained by mass polymerization at 55 s, having K-67 with a residual vinyl chloride content of 0.3% by weight, are counted on a dry polymer in a mixer for 3 minutes with a mixture of 100 g of hexanediol-1.6 and 530 water, then heat treated in a cupboard for 50 minutes at and cooled. The obtained values are given in the table. Example 7. To 10 kg of polyvinyl chloride at 62c obtained by mass polymerization, having a K-60 value and a residual vinyl chloride content of 0.2 wt.%, Calculated on a dry polymer, is added a mixture of 100 g. butene-2-diol-1,4 and 500 g of water. In a cylindrical autoclave with a capacity of 40 liters, equipped with a jacket for heating with oil and a rotor screw with blades 5 cm wide, covering the whole bottom and 80% of the side walls, and with a speed of 60 rpm, the polymer is treated with the mixture 90 min under pressure of 250 mm Hg The temperature of the oil bath is 92 ° C, the temperature of the polymer. During the treatment, a low flow of air is passed through the autoclave. After 90 minutes, the reactor is connected to the atmosphere and the autoclave is cooled. The data obtained are shown in the table. In the example, in the apparatus of example 7 to 10 kg of polyvinyl chloride obtained by mass polymerization at b9c, a mixture of 200 g of decanediol-1, 10 and 500 g of ethanol is added and subjected to heat treatment for 120 minutes at a product temperature of 100 mm Hg. and -60 rpm agitators, with the passage of a weak stream of air. Then the reactor is communicated with the atmosphere and the autoclave is cooled, the obtained data are given in the table. 3 EXAMPLE 9. To 10 kg of polyvinyl chloride obtained by mass polymerization at 62 C with a residual vinyl chloride content of 0.2 wt.%, Calculated on a dry polymer, is added a mixture of 200 g of polyglycol corresponding to the average formula HO (, yJ and 500 g of water, poached 3 minutes in a mixer and then heat treated, dried in a drying oven for 280 minutes and cooled. The data obtained are shown in Table 1. Example 10, Worked as in Example 1 using the same polymerizate, but instead of a mixture of diglycol water, a mixture of 50 g propane -1, 3 and 500 g of water. The workings are carried out at the temperature of the product.The data obtained are shown in Table 1. Example 12. The procedure is carried out as described in Example 1 using the same polymerizate, but a mixture of 200 g of tert.pentylglycol and 500 g of water is added in place of the mixture of diglycol-Vrd. Table 1. EXAMPLE 13 1 kg obtained by polymerization in aqueous suspension with a copolymer of vinyl chloride with vinyl acetate with a content of 90% by weight of polymerized vinyl chloride units and 10% by weight of polymerized vinyl acetate units, (K-60) are smeared with a solution of 10 g diglycol in 50 ml of methyl alcohol for 3 minutes in a high-speed mixer. The mixture is held for 4 hours (thin layer) in air at room temperature, and volatile methyl alcohol is evaporated. The polymer treated in this way, together with the untreated polymer (blank), is treated for 3 hours at a temperature of 87 s in an air circulation oven. Cool the polymer and determine the color of the color. The polymer prepared according to the invention, treated in the presence of 1 wt.% Diglycol, has a color rating of 1-2, and a sample has a color index of 4 for sample. EXAMPLE 14, Example 13, 1 kg obtained by suspension polymerization in medium at a temperature polyvinyl chloride with K-55 is mixed with 10 g of polyglycol of the averaged formula HO (CH2CH2O) s dissolved in 150 ml of water. The obtained yuk: the polymer is dried overnight in air at room temperature and then subjected to heat treatment in Example 13, obtained according to the invention) the polymer treated in the presence of 1 weight,% by needle, has a color index of 1-2. In untreated polymer (dry weight test), the color index is P r and measures 15. 10 kg of the resulting polymerization in an aqueous emulsion at a temperature of polyvinyl chloride with K-59 is mixed in a mixer with 100 g of diglycopes dissolved in 500 ml of methyl alcohol, and at the same time Methyl alcohol is removed by flushing the mixer with nitrogen, 500 g of the polymer treated in this way, along with the raw polymer (blank), are treated for 3 hours at 87 ° C in an air circulation oven. In the polymer obtained according to the invention, treated in the presence of 1 weight,% diglycol, index color: eta 1, raw material polymer (blank) color index 4. And p and me 16. It is 500 g obtained by bulk polymerization at 63 ° With a copolymer with K-50 and a content of 90% by weight of polymerized vinyl chloride units and 10% by weight of polymerized vinyl acetate units, the mixture is thoroughly mixed with 5 g of diglycol dissolved in 50 ml of water. After water is removed at a temperature of 40 ° C in a vacuum oven, the copolymer treated with the process is indicated together with the untreated copolymer (blank test) is treated for 3 hours at 87 ° C in an air circulation oven. 3 In the case of the diglycol copolymer treated in accordance with the invention in the presence of 1 wt.%, The color index is 1, and the raw polymer (blank test) has a color index of 4. Example 17: 5 kg of grafted suspension polymerization in an aqueous medium a copolymer with a content of 93.5% by weight of polymerised vinyl chloride units, 3.6% by weight of polymerized ethylene units and 2.9% by weight of polymerized vinyl acetate units are thoroughly mixed with 50 g of diglycol dissolved in 200 ml of methyl alcohol. The polymer is then dried for 20 hours at room temperature, until almost complete evaporation of the methyl alcohol. The graft copolymer treated by the above method together with the untreated graft copolymer (blank) is treated for 3 hours at a temperature in a dry air circulation. In the Processed Invention in the presence of 1 weight 4% polymer diglycol, the color index is 1, the untreated graft copolymer (blank) has a color index of 4. Thus, the proposed method allows to significantly reduce the content of residual monomer in polyvinyl chloride, with a noticeable change in the color of the latter after no processing is observed.

921 5077 85250 90127.5 97100 mm hg 120194 751 280350 180255 180255 180255 180255 300425 180255 80255 180255 10 8 11 7 1 5 6 8 15 21 9 b

57

Propandiol-1, 3 0.5

57

Butandiol-1, 4 1

57

Neopentyl glycol2

Claims (2)

1.Worked for the Federal Republic of Germany №2162860, class 39 in 1/96, published. 1972. 2. Published for the Federal Republic of Germany No. 2331895, cl. 39 В 1/96, published 1973 (prototype).