CS217490B1 - A method for producing vinyl chloride suspension copolymers - Google Patents

Abstract

The production of suspension copolymers of vinyl chloride with a mixture of at least two C3 to C5 alkenes, usually also with the co-action of alkanes, or additionally dienes, is carried out by suspension copolymerization at a temperature of 10 to 90 °C (40 to 65 °C) with the initiating effect of previously prepared or "in situ" formed organic peroxides. A suitable mixture of C3 to C5 alkenes, alkanes and dienes is the C^-hydrocarbon fraction from the catalytic cracking of higher petroleum fractions, but especially the residual pyrolysis C4-fraction, practically after the separation of 1,3-butadiene, or isobutene. Propene, isobutene, 1-butene and cis-2-butene and trans-2-butene are copolymerized with vinyl chloride.

Description

2

BACKGROUND OF THE INVENTION The present invention relates to the production of suspension co-polymers of vinyl chloride with olefinically unsaturated hydrocarbons of C3 to C5 as co-monomers on conventional polymerization equipment using technically available mixtures of alkenes and optionally diene with a double bond in the molecule.

It is known that the industrial application of copolymerization of vinyl chloride with ethylene (V. Brit. Pat. No. 1,339,182) and propene [Jap. Nos. 7,236,022 (1972), 7,231,700 (1972) and 7,316,715 (1973); NDR pat. 111 385 and Israeli Pat. 31159] However, in the case of ethylene as a comonomer, due to its low criticism, a relatively high pressure is needed, as is also evident from the pressures of the impact of pressure on the copolymerization of vinyl chloride with ethylene [Burkhart RD, Zutty NL: J. Polym. Sci. A 1, 1137 (1963); Duntov, F.I., et al. soed. A 9, 1920 (1967); Erusa-limski B. L. et al., Makromol. Chem. 104, 288 (1967)]. In addition, the lower ethylene selectivity complicates the copolymerization itself. The vinyl chloride copolymers with ethylene are well processed, have improved impact strength, and the glass transition temperature and tensile strength are close to PVC (V. Brit. Pat. 107 107; 1110147 and 1 123 751). ). In the case of the polymerization of vinyl chloride with propene but with increasing copolymerization time, the total pressure in the autoclave increases with the conversion. This is also related to the fact that vinyl chloride enters the polymer chain faster than propene, thereby increasing the propene content of the monomer mixture during copolymerization [Buening R. et al .; Angew. Macro-mol. Chem. 25, 27 (1972); Ulbricht J., Wolf K. F .: Plaste und Kautsch. 22, 559 (1975); Langsam M .: J. Appl. Polym. Sci. 4, 21, 1057 (1977)]. The unfavorable consequence of this may be the limited use of a polymerization apparatus, pressure-sized for the homopolymerization of vinyl chloride, a lower pressure than is required for its copolymerization with propene to a high degree of conversion. At low concentrations in the starting mixture, the monomer reaches the maximum maximum pressure at the moment when the liquid phase of the vinyl chloride is exhausted. However, the excellent flow and processing properties, in particular the suspension copolymervinyl chloride with propene, are evident [Heiberger C.A. et al .: Polym. Eng. Sci. 9,445 (1969); Fujiyama M. et al .: KobunshiRonbunshu 32, 7, 418 (1975); Macho V. et al., NDR Pat. 142, 198 (1980)]. Similarly preferred is the vinyl chloride suspension isobutene [(Bayer AG): franc. Pat.1 524,569, V. Brit. pat. 1,115,685; Macho V.a et al .: GDR pat. 142 198] as well as the ternary copolymer of vinyl chloride with propene and isobutene [Grzywa E. et al .: pat. PER 82 928 (1976)]. However, their production requires pure and isolated comonomers. The solution is also a suspension copolymer of vinyl chloride with a mono-isoolefin prepared by suspension copolymerization of vinyl chloride with mono-isolefinic presence of inorganic salts which improve the copolymer granulometry (Heldsworth R. S. et al., U.S. Pat. No. 3,063,977). This method also requires isolated mono-olefins. On the other hand, another method (Chatelain J .: NSRpat. 1 910 984) uses a mixture of C2 to C4 alkenes, but only for block copolymerization. The block copolymerization of vinyl chloride with ethylene and other olefins is can also be initiated by organometallic Ziegler — Nafta systems [Jap. pat. Finally, according to another method (French Pat. No. 101,112), vinyl chlorides are copolymerized with other individual vinyl comonomers such as styrene, alpha-methylstyrene, p-methylstyrene, with cyclopentadiene and with individual 1-alkenes C4 to C8. The disadvantage is the need for not only refined but also isolated individual comonomers. In addition to this, it is very difficult and only slightly copolymerized with styrene.

However, the method of the present invention takes advantage of the known processes for producing vinyl chloride co-polymers with alkenes and enhances the above-mentioned problems, employing technically available mixtures of alkenes, alkanes and also dienes.

According to the present invention, there is provided a process for the production of suspension copolymers of vinyl chloride with olefinically unsaturated hydrocarbons having from 3 to 5 carbon atoms and / or modified suspension polyvinyl chloride, by freeze-drying suspension copolymerization at a temperature of 10 to 90 ° C, using a free-radical initiator. and / or pre-prepared, and auxiliary substances, such as protective colloids, in particular dispersants, stabilizers, optionally pH-adjusting agents, by means of vinyl chloride suspension being copolymerized with a mixture of at least two C3 -C5 -alkenes, as a rule also the addition of dienes, preferably alkene-C4-fractions from the catalytic cracking products of hydrocarbons and / or alkenes of the residual pyrolysis C4-fraction, added to the copolymerization medium at a single rate or at a rate of 0.05 to 35%, , preferably 1 to 10% by weight of vinyl chloride.

The process of the present invention is readily accomplished on a conventional vinyl chloride suspension polymerization apparatus, since the total overpressure under optimum copolymerization temperature conditions does not exceed 1 MPa. Another advantage is the availability of raw materials - there is no need for energy and equipment for the isolation of individual alkenes. In addition, especially in the case of the use of free-dical initiation systems formed in situ, fine powder copolymers and, last but not least, the mainly due to various quantities of monomers it is good to regulate the average molecular weight of the copolymers, and of these and, of course, the qualitative and at the same time processing properties of the copolymers. Finally, the advantage of the process according to the invention is that, when using the 3 C 3 to C 5 comonomers below 1%, in particular in the range of 0.1 to 0.7%, based on the weight of vinyl chloride, such a reduction in polymerization rate is not evident. a more pronounced reduction in K value. It receives substantially homopolymeric suspension PVV. However, its morphological and other physico-chemical and mechanical properties, characterized by quite workability, differ from comparable PVC-like suspension values. Thus, a modified PVC suspension is obtained.

In the manufacture of vinyl chloride suspension copolymers, the water module may be varied at a wide range. Particularly suitable as free radical initiators are individual organic peroxides and mixtures thereof, such as dilauroyl peroxide, dibenzoyl peroxide, di-acetyl peroxide, dioctanoyl peroxide, tert-butyl peroxypivalate, dialkyl peroxydicarbonates, acodiisopropyl peroxydicarbonate, diethyl peroxydicarbonate, dibutyl peroxydicarbonate, di-2-ethyl hexyl- peroxydicarbonate, dicetyl peroxydicarbonate and the like, alkylaryl peroxydicarbonates, alkylcyclohexylperoxydicarbonates and other mixed and mixed organic peroxides (auto-certificate 175 908), acetylcyclohexylsulfonyl peroxide, organic hydroperoxides known redox systems and radical initiators. In doing so, a number of individual and mixed organic peroxides can be formed in situ and starting materials, e.g. authorizations 155 867,155 868, 155 869, 163 502, 171 356, 170 326,172 673 and 175 738. Protective coils, especially the dispersants known to this effect, include partially saponified polyvinyl acetate, polyvinyl alcohol, cellulose ethers, to the adjuvants. alkylhydroxyalkyl ethers, hydroxyalkyl ethers, polyacrylamide, propoxylated and ethoxylated polyols, nonionic surfactants. The excipients also include partially esterified diolefin polyols, partially saponified fats, high saturated and unsaturated alcohols, esters of higher fatty acids and partially etherified diols to polyols, as well as the polyol itself, e.g., monopentaerythritol, dipentaerythritol. The excipients also include moles regulators. weight, then stabilizing the copolymerization environment, the unstability of the copolymers produced, such as, for example, organic and inorganic antioxidants, reducing substances.

Suspension copolymerization of vinyl chloride takes place with at least two alkenes C3 to C5, generally co-acting with C3 to C5 alkanes, such as propane, n-butane, isobutane, n-pentane, isopentane, but less likely, but cyclopropane and the like are available. Of the dopants, the most common are alene, 1,3-butadiene, 1,2-butadiene, cyclopentadiene, isoprene, and piperyl. However, from a technical and economic point of view, it is most appropriate to apply mixtures of carbon-hydrocarbons of the C-fraction from the catalytic cracking, possibly the hydrocracking of higher petroleum fractions, but in particular the residual pyrolysis of the C4-fraction, ie generally substantially depleted It is also usually obtained after refining and isolating 1,3-butadiene from the pyrolysis C4-fraction from which at least a substantial part of the isobutene can still be isolated. However, the residual C4-fraction thus obtained is still a suitable mixture of monomers also for suspension copolymerization with vinyl chloride.

The monomer and comonomers can be dispensed into the polymerization mixture in one or more portions during copolymerization. At the end of the copolymerization, the suspension of the copolymer can be stabilized by known steps.

Unconverted monomers, respectively. the comonomers are degassed from the copolymer suspension and removed for recovery or further use or for flotation. Further details of the method as well as the advantages will be apparent from the examples. Example 1

2000 g of distilled water, 210 g of an aqueous solution of methyl-hydroxypropylcellulose (Methocel F50) with conc. Conc., In the form of a 5 dm 3 stainless steel autoclave, equipped with a duplicator, anchor stirrer, a pressure gauge and the appropriate apparatus, were charged. 1 wt. and 4 g of dicetyl peroxydicarbonate (Perkadox 24). After closing the autoclave and removing the air, the agitator is started and 70 g of residual pyrolysis C4 fraction, in% by weight, is dispensed: 0.23 propane; 0.49 propene; 3.29 isobutane; 1.11 isobutene; 34.88 n-butane; 28,75 1-butene; 8,45cis-2-butene; 21.0 trans-2-butene and 1.9 iso-pentane. 1300 g of vinyl chloride are then metered in. Subsequently, the contents of the autoclave are heated to 50 [deg.] C. with constant agitation and maintained at + 0.5 [deg.] C. for 12 hours. The suspension of the copolymer is filtered off, washed three times with distilled water on the filter, and then dried in a hot air oven at 52 ° C with a perfect weight. The copolymer obtained is weighed and analyzed. The weight of the copolymer is 760 g, of which K is 57.1. The chlorine content of the copolymer is 55.24% by weight, which corresponds to 2.1% zakopolymerized alkenes, the moisture content, residual initiators and monomers in the copolymer being taken into account in this and other examples.

The autoclave and the process specified in Example 1 are used. The batch is made up of 2000 g of distilled water, 260 g of methylhydroxypropylcellulose, 4 g of dicetyl peroxydicarbonate, 40 g of the residual pyrolysis C4 fraction specified in Example 1 and 1300 g of vinyl chloride. At a temperature of copolymerization of 50 ± 0.5 ° C for 11 y 2, 902 g of copolymer with an iK value of 59.6 and a chlorine content of 55.62 wt.

Claims (1)

4 content of 1.5 wt. zakopolymerized alkenes. EXAMPLE 3 22,000 g of distilled water, 1300 g of an aqueous solution of methylhydroxypropylcellulose with a conc. Of water are metered into a 50 dm 3 stainless steel autoclave, similar to that of 5 days 3 in Example 1. . 1% by weight, 52 g of xylene solution di-2-ethylhexyl peroxydicarbonate conc. 50% by weight, prepared from 2-ethylhexyl chloroformate, hydrogen peroxide and sodium hydroxide according to U.S. Pat. aut. After closing and removing the air from the autoclave, 396 g of a C 3 to C 5 hydrocarbon mixture of this composition (% by weight): propane with carbon dioxide of 0.70 are added; propéna0,68; isobutane 5.59; isobutene 0.1; n-butane29.54; cis-2-butene 6.23; 1,3-butadiene 0.1, trans-2-butene 17.11; 1-butene 37.47; isopentane 1.95; isopentene 0.4 and finally 8000 gvinyl chloride. The autoclave is heated to 52 ° C and maintained at a temperature of + 0.5 ° C with an autoclave sheath at constant temperature (200 rpm / min) for 12 h. Thereafter, the autoclave contents are cooled and unreacted rnono -measures to be burned. Unconverted hydrocarbons have a composition other than that used in the feed, which is associated with the reactivity of the 1,3-butadiene alkene as well as their reactivity. Thus, propane with carbon dioxide is 2.87% by weight; propene 0.3 wt%; isobutene 0.03%; isobutane 13 wt%; n-butane34.2 wt.%; 1-butene 31.1 wt%; 1,3-butadiene 0.0%; cis-2-butene 3.7% and trans-2-butene 13.7% by weight. Of these results, they have copolymerized not only the 1-alkene dienes, namely the particular propene, 1,3-butadiene 1-butene, but also the 2-butenes and the faster cis-2-butene therefrom. The product is filtered off, washed three times with distilled water, dried under reduced pressure at 50 ° C and weighed. 5.95 kg of copolymers having a K value of 53.7 and a chlorine content of 55.1% are obtained, corresponding to 2.5% by weight of the copolymerized alkenes. The bulk density of the copolymer powder is 655 gm-dm-3 and the object of the process for the production of 3 to 5 carbon-olefinically unsaturated olefinically unsaturated olefinic unsaturated hydrocarbon suspensions and / or unmodified polyvinyl chloride suspensions, in noradical suspension copolymerization at 10 to 90 ° C, the use of a radical-forming initiator formed in situ and / or pre-formed and auxiliary substances such as protective colloids, especially dispersants, stabilizers, and optionally pH regulators, characterized by the fact that vinyl chloride the slurry distribution thereof according to the following: grain 0.25 mm 2.4%; grain 0,20 mm 16,0%, grain 0,18 mm 8,0%; grain 0.10 mm47.6%; grain 0.063 mm 12.4% and grain size <0.063 mm 13.6%. EXAMPLE 4 24 kg of distilled water, 2.8 kg of an aqueous solution of methyl hydropropylcellulose with conc. 1% by weight, 27 gdilauroyl peroxide and 27 g of bis- (4-tert-butyl-cyclohexylperoxycarbonate), 12.1 kg of vinyl chloride and 0.5 kg of a mixture of C4-C5 hydrocarbons, 80% by weight isobutene 6.5% isobutane, 3.9% cis-2-butene, 8.2% trans-2-butene and 7.9% pentanes. The copolymerization is carried out at a temperature of 50 + 0.5 ° C over a period of 20 h, yielding 8.75 kg of a powdered copolymer of K value of 50.8 and a chlorine content of 54.6% by weight, corresponding to 3.2% by weight. . zako-polymerized alkenes. EXAMPLE 5 24 kg of distilled water, 2.3 kg of an aqueous solution of methylhydroxypropylcellulose with conc. 1 wt. and 0.4 kg of a hydroxypropyl cellulose aqueous solution of conc. 1 wt. and 0.1 kg of an aqueous solution of hydroxyethylcellulose with conc. 1 wt. Thereafter, 277 g of an aqueous hydrogen peroxide solution of conc. 3 wt. and 48.5 g of aqueous sodium hydroxide solution with conc. 40 wt. At the same time, 33.5 g of chloroformic isopropylated with conc. 96% and 32.3 g of benzyl chloride with conc. 97%. Further, after removing the air, 12.1 kg of vinyl chloride and 0.5 kg of a C4 to C5 hydrocarbon mixture as specified in Example 4 are carried out. The copolymerization is carried out at 50 + 0.5 ° C for 20 h. a powdered copolymer having a K value of 50.8 and a chlorine content of 54.6% by weight, which corresponds to a maximum of 3.2% by weight. of copolymerized alkenes. The proportion of grain copolymers under 0.063 is up to 56%. The present invention copolymerizes with a mixture of at least two C 3 -C 5 alkanes, generally also alkanes, optionally with dienes, preferably with C4-fraction alkenes from catalytic hydrocarbon cracking products and / or with C4-residual pyrolysis. fractions added to the copolymerization medium in a single or sequential manner in an amount of 0.05 to 35%, preferably 1 to 10%, calculated on the weight of the vinyl chloride. Printed by TSNP, n. Martin Price Kčs 2.40