CS271432B1 - Method of graft copolymers production - Google Patents

Abstract

The solution involves the production of grafted copolymers. The object of the solution is a method of producing grafted copolymers, which consist of the following: Cationic polymerising monomers are polymerised or copolymerised at temperatures of +20degrees C to - 120 degrees C in the presence of an initiation system consisting of a polymer or oligomer compound containing in the strand at least one structure unit with chlorine atom bound on tertiary carbon and components formed by the Lewis' acid, as aluminium chloride or their mixtures with ferric chloride, where the molecular ratio of the Lewis' acid and monomers is in a range of 50 to 1.10<-3>, or in the polar or halogen solvent media or their mixtures with non-polar solvents , or in the aromatic solvents or their mixtures with polar halogen solvents.

Description

The invention relates to the production of graft copolymers.

It is clear from IUPAC literature and international symposia on the presentation of the preparation of macromolecular substances that syntheses of block and graft copolymers are of interest to world research institutes, due to the possibility of wide application of these copolymers in the processing field.

Polyvinyl chloride (PVC) is one of the most widely used industrial polymers with wide application. Modification of the PVC polymer chain by cationic grafting of other monomers is not easy because the PVC chain contains only a small amount of constitutional units with allyl-linked chlorine (about 0.2 mol%). Due to the very low concentration of reactive groups in the PVC chain, this polymer becomes almost unusable for grafting with cationic polymerizing monomers.

Although the literature describes the reactivity of PVC in the presence of some Lewis acids such as aluminum chloride (AlCl 3) and titanium tetrachloride (TiCip (PHPlesh, Chem. Ind., 1958; PHPlesh, British Patent No. 817,684 (Pec.5, 1956)), it is clear that grafting of PVC with cationic polymerizing monomers is poorly effective and therefore disadvantageous as it leads to the formation of homopolymers rather than to grafted PVC, as pointed out by Prof. Kennedy (JP Kennedy, Cationic Graft Copolymerization, J.Appl. Polym.Sci). (Appl.Polym.Symp.30, Akron) Kennedy states that when PVC is mixed in AlCl 3 or TiCl 3, dehydrochlorination of the polymer occurs and even a small amount of hydrogen chloride (HCl) formed in the reaction Bystem creates a very reactive initiation system of HCl / AlCl 2, respectively. HCl / TiCl 2, which preferably protonically initiates, for example, the polymerization of isobutylene to produce polyisobutylene with low yield of grafted PVC.

The use of additional Lewis boric chloride (BCl 3) as a co-initiator to graft PVC with cationic polymerizing monomers is possible, but only after prior dehydrochlorination of the PVC with an alkali such as sodium hydroxide. Partial dehydrochlorination of PVC leads to an increase in the content of allyl chlorine structural units in the chain. Non-dehydrochlorinated, commercial or laboratory synthesized PVC is almost unreactive in the presence of boron trichloride (BCl4) and is not grafted with isobutyl, for example (S.N. Gupta and J.P. Kenedy, Polym. Bull. 1, 253, 1979). Dehydrochlorination of PVC is disadvantageous since it involves relatively expensive dissolution of PVC in an organic solvent, reaction with a base, precipitation of PVC from the solvent and subsequent thorough washing with water to neutral reaction and careful drying. *

The use of expensive co-initiators as silver hexafluoroantimonate (AgSbF4) (E. Franta, F. Afshar-Taromi and P. Rempp, Makromol. Chem., 177, 2191 (1976)) does not, for economic reasons, give hope for the practical application of PVC grafting in industrial gauge tissue.

Only recently, isobutylene grafting on PVC in the presence of an alkyl-aluminum compound has been described (B. Ivan, J.P. Kennedy, T. Kelen, F. Tudos, J. Macromol. Sci.-Chem., A16, 1473 (1981)). First, a free-radical copolymerization of vinyl chloride with 2-chloropropene was performed, and only then the resulting vinyl chloride / 2-chloropropene copolymer was grafted in the presence of diethyl aluminum chloride (EtgAlCl). The disadvantage of this procedure is that, in the presence of an alkyl aluminum compound, the termination reaction in the counterion ions ceases to alkylate or hydride the ends of the growing polyisobutylene branches and the grafted tnakroiner is no longer reactive (JP Kennedy, Cationic PolycnerizaCS 271 432 Blaction of Olefins: A Critical Inventory , John Wiley and Sons, A. Wiley-Interscience Publication New York, 1975 1975 P. Kennedy and E. Maréchal, Carbocationic Polyrnerization, John Wiley and Sons, A. Wiley-Intersciences Publication, New York 1932, p. -223).

In the basic research of cationic polymerization, alkyl halides or macromers, such as telechelic polyisobutylenes containing chlorine bound to tertiary carbon, have long been considered non-reactive when using Lewis acids boron trichloride (BCl?) And TiCl? (J. Puskás, G.Kaszás, JD Kennedy, T. Kelen, F. Tudos, J. Macromol. Sci.Che A 18, 1229 (1982-83); A. Gandini and H. Cheradame, Advances in Polymer Sci. 34/35, 169 (1980)) .

Only in 1984 according to MS. No. 239,995 (Method for the preparation of aliphatic halinifers - L.Toman) discloses a method of initiation by tertiary butyl chloride in the polymerization of isobutylene in the presence of BCl -. The invented new tert-butyl chloride / BCl 2 initiation system was used to synthesize heterothelechelic polyisobutylene (t-BuPIB-Cl) according to U.S. Pat. No. 246,647 (Method of making polyisobutylene with reactive groups in the polymer chain - L. Toman). The knowledge of the initiation of isobutylene polymerization by the t-butyl chloride / BCl 4 system was then extended to the polymerization of ob-methylstyrene initiated by heterothelechelic polyisobutylene in the presence of BCl 4 (t-BuPIB-Cl / BCl 4). The initiation system thus proceeded to quasi-polymerize the .beta.-methylstyrene to produce the polyieobutylene-b-poly-methyletyrene block copolymer according to U.S. Pat. No. 267,629, (Method of preparation of block copolymers by cationic polymerization - L.Toman, J.Spevacek, J. Danhelka, M.Nahunek).

SUMMARY OF THE INVENTION The present invention relates to a process for the production of graft copolymers, characterized in that the cationic polymerizing monomers or mixtures thereof are polymerized or copolymerized at a temperature of +20 ° C to -120 ° C in the presence of an initiator system consisting of consisting of a copolymer or oligomer having a number of carbons> 5, comprising in the chain at least one structural unit with a chlorine atom bound to a tertiary carbon and Lewis acids, such as boron trichloride, titanium tetrachloride, aluminum chloride or mixtures thereof with iron chloride; the ratio of Lewis acid to monomers is in the range of 50 to 1.10, optionally in the environment of polar halogenated solvents or mixtures thereof with non-polar solvents, optionally in aromatic solvents or mixtures thereof with polar halogenated solvents.

In carrying out the process of the invention, the monomer or monomer mixture can be continuously fed into a preformed initiator system or in a conventional manner by mixing the initiator system 8 with monomer.

The polymerizations or copolymers are carried out without a co-solvent or in the environment of polar halogenated solvents such as methyl chloride, methylene chloride, ethyl chloride or mixtures thereof with non-polar solvents such as heptane, carbon tetrachloride, optionally mixed with aromatic solvents such as benzene, toluene.

As an oligomer or polymer containing in the chain at least one structural unit with a chlorine atom attached to a tertiary carbon, for example, a vinyl chloride-2-chloropropene copolymer, hydrochlorinated polyisoprene, hydrochlorinated butyl rubber with other monomers or chlorinated polypropylene is used.

CS 271 432 B1

An advantage of the polymerization or copolymerization process of the cationic polymerizing monomers or mixtures thereof according to the invention is that, when using the initiator system, the oligomer or the chlorine-containing polymer bound to the target, carbon / BCl4 and / or TiCl4 and / or AlClp respectively ₃ - graft copolymers are formed which contain reactive chlorine at the ends of the grafted branches which can be used for further reactions, for example for polymerization or copolymerization of other monomers, for example styrene. The graft copolymers thus formed melt the structure of the block copolymers in their grafts.

The grafting according to the invention can generally be indicated by the scheme, for example in the case of grafting isobutylene from vinyl chloride / 2-chloropropene copolymers using BC1 ₃ as initiator:

CH.CH.

I ³ I

CH.C PVC-PVC / wPVC-CH.C ² PVC-I

ClCl pci ₃

CH.

I ³

PVC-CH.C-PVC ^ 3 ·

PVC-CH ₀ C-PVC

ВСЦBC1 ₄ * “ ^С 4 ^Н 8

IN

CH, CH,

I ³ I

PVC-CH, C-PVCr, PVC-CH, C-PVC

LL

> IB PIB 1 CH _O 1 ² 1 CH _O 1 ² O-CH ₂ CH ₃ -C-CH. Cl Cl BC1. BC1.

Chlorination of the end of the polyisobutylene chain has been previously described in the disappearance of counter ions: JP ^ θ ---->/> уС-С1 + BC1 ₃ (JP Kennedy, SY, Huang and Feinberg, J. Polym.

Sci. 15, 2801 1977 J.J. Kennedy and Merachal, Carbocatonic Polymerization, A. WileyInterscience publicatio New York 1982).

According to the invention, the chlorine-containing polymers or macromers on tertiary carbon can both initiate cationic polymerization and participate in the transfer reaction and therefore become polymer initiator-transfer substances, polyinifers, to form

CS 271 432 B1 functionalized graft copolymers, which is a significant advantage of the invention. The initiation-transfer reaction by the polyinifer may be illustrated by the following scheme, wherein the polyinifer is a vinyl chloride / 2-chloropropene copolymer in conjunction with BCl 2,

PVC I PVC 1 1 CH, 1 ^g CH i ^г CH.-C (R) BC1 + nM 1 -----> ^с н ₃ -с- (М) _п ^ _ PVC $ PVC i PVC 3 PVC 3 PVC 3 PVC 1 CH, I ² CH, I ² CH, I ² CH, 1 ² CH - C - (Μ) + 3 1 n-1 Cl-C-CH. 1 ³ -----> CH-C- (11) ,, -1 J 1 n + ® C - CH, ³ PVC PVC PVC PVC

Where n is the number of cationic polymerizing monomeric molecules of type M.

The graft copolymers prepared according to the present invention can be widely used, in particular as a polymer specialty, preferably as a compatibilizer for processing incompatible polymeric materials. Examples are graft copolymers vinyl chloride / 2-chloropropene isobutylene and graft copolymers vinyl chloride / 2-chloropropene-g-poly-8-butylene-b-polystyrene, which are suitable compatibilizers for processing PVC-ABS (acrylonitrile-butadiene-styrene) mixtures. The compatibilizing efficiency of these graft copolymers can be influenced by the extent of the grafting and the selection of the VC / 2-CP copolymer in terms of molecular weights and the 2-chloropropene structural units content. It is therefore clear that a number of graft copolymers having specific properties tailored to the present invention can be prepared.

When using e.g. hydrochlorovaného or partially hydrochlorovaného polyisoprene or butyl rubber polymerization of the invention when using BCl ^ may be indicated by scheme (in which PIP denotes constitutional isoprene units, - (CH-UP ^ ^) = _CH-СЯ г) _п -)

PIP

PIP

CS 271 432 B1

CH ₃

Cl

BEEP

PIP is not a novel copolymerization with the formation of block copolymers in a base-graft graft

CH ₃

CK ₃

PIP

PIP

Obviously, a new kind of butyl rubber, i.e. a high double bond isobutylene / isoprene copolymer, can be prepared by said synthesis, which is not obtainable in the classical industrial synthesis at temperatures around -100 ° C by the AlCl ₃ / methyl chloride initiation system. The butyl rubber synthesized according to the invention is an important polymeric material particularly suitable for the preparation of new butyl rubber latexes.

According to the invention, oligomers and / or chlorine-containing polymers on tertiary carbon can be used in conjunction with, for example, β BC1 ₃ as polyinifers, wherein the cationic polymerization of the monomers or mixtures thereof can be conducted according to reaction conditions so that virtually only the grafting process and / or homopolymerization or copolymerization of monomers, respectively. Typical examples are shown in the figure which shows GPC chromatograay under various conditions of prepared graft copolymers. Curve # 1 is a vinyl chloride / 2-chloropropene (VC / 2-CP) copolymer, Curve # 2 is a blend of a polyisobutylene (PIB) homopolymer with a graft vinyl chloride / 2-chloropropene-g-polyisobutylene copolymer (VC / 2-CP-) curve 3 is only a vinyl chloride / 2-chloropropene-g-poly (t-butylene) graft copolymer (VC / 2-CP-g-PIB).

The process for the preparation of graft copolymers by cationic polymerization of the invention is further elaborated on several typical examples. In all the examples below

CS 271 432 B1 the polytnerisations were carried out in glass ampoules equipped with a piercing cap or in a glass reactor equipped with a stirrer. Solutions of the initiator system, for example VC / 2-CP 8 BCl 2 in dichloromethane (CH ₂ Cl ₂ ), were prepared in glass ampoules fitted with a three-way Teflon cap for dispensing the components in a stream of nitrogen. The polymerizations were carried out under dry conditions under dry nitrogen.

Polystyrene standards were used to easily compare the molecular weights of polymers and copolymers. Molecular weights were subtracted from the maxima. GPC curves (gel permeation chromatography) and these values are therefore apparent based on polystyrene. GPC measurements were performed in tetrahydrofuran solution. The polymeric initiators were dissolved in dichloromethane and dried with molecular sieves for 24 hours before use.

Example 1

Grafting was carried out with isobutylene in methylene chloride (CH ₂ C1 _2). Pre-prepared dichloromethane (CH ₂ Cl ₂ ) solution of vinyl chloride / 2-chloropropene (VC / 2-CP) (I) copolymer (molecular weight of type (I) M ± 60 000, copolymer contained 5.1 mol%) 2-chloropropene structural units in the polymer chain) with BCl 2. After mixing the reactants with the monomer at -20 ° C, the concentrations were as follows: [isobutylene] = 5 mol / l, fvC / 2-CP] = 12.0 g / l, [ВС1 ^] = 4.5 · ¹⁰ mol / l 1. After stirring at -20 ° C for 5 min, the reaction mixture was cooled to -70 ° C and after 1 h the reaction was stopped by the addition of methanol at a conversion of about 90% by weight, calculated as isobutylene. The product was partially soluble in heptane and contained swollen gels. Molecular weight of product M ± 130 000.

Example 2

Isobutylene grafting was performed in a CH ₂ Cl ₂ solution using an initiation system as in Example 1. After mixing the reactants 8 with the monomer at -20 ° C, the concentrations were as follows: [isobutylene] = 4.3 mol / l, [vC / 2-] CP] = 5.6 g / l, [scij = 2.25. 10 ^{2 2} mol / l. After stirring at -20 ° C for 10 minutes, the reaction mixture was cooled to -75 ° C and after 15 minutes the reaction was stopped by the addition of methanol at a conversion of about 20% by weight, calculated as isobutylene. A comparison of the GPC chromatogram of the product with the starting VC / 2-CP copolymer is shown in Figure 2 (curve 2). The product had the character of elastic rubber. Molecular weight of product M / 450 450 000.

Example 3

Isobutylene grafting was performed as in Example 1. After mixing the reactants with the monomer at -20 ° C, the concentrations were as follows: [isobutylene = 4.3 mol / l, [vC / 2-CP] = 4.87 g / l, [ BC1 ₃ J = 1.6-lCT ² mol / l. After stirring at -20 ° C for 3 minutes, the reaction mixture was left at this temperature for 2 hours and then cooled to -75 ° C. After stirring at -75 ° C for 20 minutes, the reaction was quenched with methanol at a conversion of 35% by weight, calculated to isobutylene. A comparison of the GPC chromatogram of the product (curve 3) with the starting VC / 2-CP copolymer (curve 1) is shown in Figure 1. The product was elastic rubber. Molecular weight of product M 470 000.

Ί

CS 271 432 Bl

Example 4

Isobutylene grafting was performed as in Example 1 except that titanium tetrachloride was used as the co-initiator. After mixing the reactants with the monomer at -20 ° C, the concentrations were as follows: [isobutylene] »4.3 mol / l, IVC / 2-CPj = 11.3 g / l, fTiCl 2 = 1.1.10 ^-2 mol / l 1. After stirring at -20 ° C for 5 minutes, the reaction mixture was cooled to -60 ° C and after 1 hour the reaction was quenched by the addition of methanol, resulting in a conversion of n-> 90% by weight, calculated as isobutylene. The product was partially soluble in hexane and contained swollen gels. Molecular weight of product M 140 000.

Example 5

The grafting of isobutylene and isoprene mixtures was performed in CHgClg as in Example 1, but a mixture of Lewis acids BCl4 and FeCl4 was used as co-initiator. After mixing the reactants with the monomers at -70 ° C, the concentrations were as follows: [isobutylene] = 4 mol / l, [isoprene] = 0.04 mol / l, [vC / 2-CP] »11.0 g / l, [BC1 ₃ J * 3.8.10 ^-2 mol / l, [FeCl2] J = 3 g / l. After stirring, the reaction mixture was cooled to -70 ° C and after 1 hour the reaction was quenched by the addition of methanol at a 90% by weight conversion, calculated to isobutylene. Molecular weight of product М ^ ч / ЗЗО ООО,

Example 6

Isobutylene grafting was performed in CH 2 Cl 2 · A pre-prepared CH 2 Cl 2 solution of the VC / 2-CP (II) copolymers (molecular weight of type (II) copolymers M = 28,000, a copolymer containing about 11.3 mol% of 2-CP) units in the Dolymer chain) with BCl 2. After mixing the reactants with the monomer at -20 ° C, the concentrations were as follows: [isobutylene] = 6.5 mol / l, [vc / 2-CP] (II) = 11.2 g / l, = 4.0.10 ^-2 mol / 1.

After stirring at -20 ° C for 10 minutes, the reaction dew was cooled to -70 ° C and after 15 minutes the reaction was quenched with methanol at a conversion of 18% by weight, calculated to isobutylene. The product was partially soluble in hexane and contained swollen gels. Molecular weight of M 400 000.

Example 7

The CH ₂ Cl ₂ solution containing [vC / 2-CP] (I) = 31.8 g / l and = 4.0.10 ^-2 mol / l, which was stirred at room temperature for 1 hour, was cooled to -50 ° C . Isobutylene was then slowly distilled into the mixture while stirring. At an isobutylene concentration of 2.9 mol / l, the sample taken from the reaction mixture had a molecular weight M = -90,000. Further monomer additions to the reaction mixture caused an increase in the molecular weight of the product. At an isobutylene concentration of 7.1 mol / l, the product already showed only molecular weight in hexane.

Example 8

The CHgClg solution containing [vC / 2-CP] (II) = 19.6 g / l and [BClJ = 4.0.1.0 ² mol / l was cooled to -70 ° C and slowly stirred into the mixture with stirring distilled

CS 271 432 B1 isobutylene with a total concentration of 5> 0 mol / l. After 3 hours, the reaction was quenched with methanol. A free-flowing product was obtained with a conversion of about 400 wt%, calculated on the concentration of VC / 2-CP of the original copolymers · M of the isolated product was 90,000.

Example 9

Grafting of styrene was conducted at 40 ° C with continuous slow dosing ^CH 2 ^C ^ 2 ^roztolcu ®onomeim into a preformed initiator system and cooled in CH ^ Cl ^> which obaahoval [nu / CP-2] (I) = 12 0 g / l and [BClj] = 4,0.10 ² mol /

1. The monomer solution was dosed at a rate of 2.10 &lt; -1 &gt; mol of styrene / min. After 1 hour, dosing was terminated at 90% by weight, the conversion calculated to styrene. The grafting of styrene to the VC / 2-CP copolymer was demonstrated by comparing GPC chromatograms obtained by R1 and UV detection.

Example 10

The grafting of methylstyrene and the mixture of styrene monomers with N-methylstyrene was carried out as in Example 9. The initiator system contained a fvC / 2-CPj (I) of ^3, 10.0 g / l, {/ TiCl4 = J = 1.10 ' ² mol / 1 [ВС1- ^ 3 ~ 2.1О ² mol / 1 [PECL ^ J «1 g. a solution of the monomer or mixture of monomers were fed to the speed of the initiator system 2.10" ^ mol / min. The molar ratio of [styrene] to [o-methyl styrene] = 1: 1. The grafting of the aromatic monomer onto the VC / 2-CP copolymer was demonstrated by comparing the R1 and UV GPC chromatograms of the product.

Example 11

The grafting of polyisoprene and commercial butyl rubber with vinylaromatic monomers and isobutylene was performed as follows:

a) Hydrochlorination of pure natural rubber and commercial butyl rubber, i.e. Lsobutylene / isoprene copolymers (the copolymer contained 2.4 mol% of isoprene in the chain), was carried out in a benzene solution at 5 ° C for 3 hours and 6 hours, respectively. After isolation, the products were dried in benzene first with calcium chloride (CaCl ₂ ) and reached above molecular sieves.

b) The hydrochloride products were used as initiators in CH ₂ Cl ₂ / benzene in combination with BCl 2 or TiCl 2 or BCl 2 / FeCl 2 at -40 ° C. The gradual addition of styrene or β-methylstyrene in the CH ₂ CH ₂ / benzene mixture to the preformed initiation system was carried out as in Example 9 or 10. The grafting of the aromatic monomer to the hydrochlorinated natural rubber and butyl rubber was demonstrated by comparing the R1 and UV GPC chromatograms of the product. For example, in the case of grafting of styrene hydrochloride rubber, the molecular weight M increased from 240,000 to 320,000.

c) After completion of the styrene feed, the reaction mixture was stirred at -40 ° C for 1 hour. Then, isobutylene was slowly condensed into the reaction mixture as in Example 8. The molecular weight of the product increased to a value of ^380 ООО.

Example 12

The copolymerization of isobutylene with isoprene was initiated by the VC / 2-CP (I) -aluminium chloride system. The aluminum chloride was dissolved in toluene and then this for 48 hours before use

The CS 271 432 B1 solution was mixed in VC / 2-CP (I) in dichloromethane. After 1 h activation at -10 ° C, the prepared initiation system was dosed into a mixture of isobutylene and isoprene at -70 ° C. After stirring, the reaction mixture contained: isobutylene = 3.3 mol / l, isoprene - 0.18 mol / l, VC [Beta] -CP (I) = 10 g / l and AlCl2 * 0.2 g / l. After 30 minutes, the reaction was quenched by addition of methanol at 4545 wt%, conversion calculated to a mixture of monomers (isobutylene + isoprene). Molecular weight of product M / 350 350,000 at an unsaturation of 1.6 mol%.

Claims (5)

Process for the production of graft copolymers, characterized in that the cationic polymerizing monomers are polymerized or copolymerized at a temperature of +20 ° C to -120 ° C in the presence of an initiator system consisting of a polymer or oligomer component containing at least one structural unit in the chain. with a tertiary carbon-linked chlorine atom and a Lewis acid component selected from the group consisting of boron trichloride, titanium tetrachloride, aluminum chloride, or mixtures thereof with ferric chloride, the molar ratio of Lewis acid to monomers being in the range of 50 to 1.10 &quot; in the environment of polar halogenated solvents or mixtures thereof with non-polar solvents, optionally in aromatic solvents or mixtures thereof with polar halogenated solvents. 2. The process according to claim 1, wherein the copolymerization is carried out by continuously feeding the monomer or monomer mixture into a preformed initiator system or by mixing the initiator system with the monomer or monomer mixture. 3. The process of claim 1 wherein the cationic polymerizing monomers are isobutylene, styrene, [beta] -methylstyrene, isoprene, butadiene, or mixtures thereof. 4. The process according to claim 1, wherein the oligomer or polymer containing at least one structural unit 8 of the chlorine atom bound to the tertiary carbon is vinyl chloride-2-chloropropene copolymers, polyisoprene hydrochloride, isoprene hydrochloride copolymers with other monomers. or chlorinated polypropylene. 5. Process according to claim 1, characterized in that chlorine solvents such as methylene chloride, methyl chloride, ethyl chloride or mixtures thereof with non-polar solvents such as heptane, carbon tetrachloride, optionally in admixture with aromatic solvents such as benzene, are used as the polar halogen solvent. and toluene.