DE1570707C - Process for the preparation of methyl vinyl ether homopolymers - Google Patents

Description

tion, wherein the molar ratio of dioxane to boron trifluoride is at least 1: 2 and preferably at least is about 3 to 4, with a preferred upper limit not exceeding about 100: 1 and being am most preferred range between 5: 1 and 50: 1 located. The upper limit is by no means critical. The only factor affecting the amount of Dioxane is determined by its solubility in the other substances present, namely the methyl vinyl ether monomer and the inert solvents.

In general, it can be said that above about 100: 1 which ratio has been found has already been given as the upper limit, the dioxane is insoluble and should therefore suggest this range to be selected as the final value for this ingredient. The boron trifluoride - dioxane combination - catalyst system can be in the form of a boron trifluoride-dioxane complex as such or in excess Dissolved dioxane can be used, or a boron trifluoride etherate complex, for example a boron trifluoride diethyl etherate, a boron trifluoride dibutyl etherate and the like, dissolved in dioxane, apply, whereby these combinations also produce the same unusual catalytic effects like the boron trifluoride-dioxane complex itself. If the catalyst consists of a boron trifluoride-dialkyl etherate complex consists in dioxane, the lower limit should not only be at least about 3: 1 (dioxane to Dietherat on a molar basis), but in this particular catalyst embodiment was found that this lower limit is of critical importance. The upper limit, however, is how further already stated above, 100: 1 (dioxane to diether on a molar basis), with a ratio of 50: 1 is preferred.

The process of the present invention comprises the use of highly purified methyl vinyl ether, in which the above-described catalyst system is entered, with all operations essentially be carried out with the exclusion of water and under inert atmospheric conditions. The monomer is at a temperature of about below -40 ° C and preferably below about - Maintained 55 ° C. The preferred temperature for the polymerization is that when using a Dry ice-acetone cooling mixture is reached, namely a temperature of -78 ° C. It can also Temperatures of about -100 ° C are used, to create the new products according to the present invention. Compliance with the selected temperatures within the stated range with respect to the reactants leads to the exceptional and excellent polymerization products that characterize the invention. In general it has been found that the maintenance of the optimal conditions with regard to the implementation of the polymerization to a 90% or even higher conversion of the monomer to the homogeneous polymeric product with high molecular weight within 10 to 24 hours. The higher percentage conversions are achieved in particular when the most highly purified reactants and Catalysts in the region of the upper limit of the preferred catalyst concentration can be used. This concentration, which depends on the amount of monomer present, can range from about 0.01 to about 1.5 mole percent, and preferably from about 0.05 to about 0.5 mole percent.

As stated earlier, a preferred condition of the polymerization is use an inert, non-reactive solvent as a carrier for the methyl vinyl ether monomer (see above that the reaction system, d. H. the solution, at the beginning of the polymerization reaction, is liquid) to the largest Degree of conversion and to obtain a polymer of the best and most optimal properties, which is also largely due to the fact that the solvent or diluent present exerts a moderating influence during the polymerization and undesirable reactions and avoids a heterogeneity of the product, which under other conditions as a result of the exothermic Nature of the polymerization could arise. The use of such inert solvents or thinners in the polymerization of vinyl ethers. known per se, but it is in the present reaction to prefer an aromatic hydrocarbon and preferably toluene for the said Purposes to use as a solvent. It is possible to use it together with aliphatic hydrocarbons, such as heptane, but it has been found that no more than 60 percent by volume of aliphatic hydrocarbons are to be used. While with similar reactions halogenated hydrocarbons have also been proposed as solvents, it is with the It is preferable not to use the polymerization process of the present invention because, As has been found, the products then obtained do not have the optimally favorable properties distinguish. The amount of solvent that is used should not be less than about 0.5 ecm per gram of monomer and no more than about 25 ecm per gram of monomer. Within this Limits is the preferred ratio of monomer to solvent, expressed in grams per cubic centimeter, at 1: 2 to 1: 10.

It has already been emphasized that the reactants in a high degree of purity and also substantially should be anhydrous, and it is therefore very desirable that the used. Methyl vinyl ether monomer is carefully converted into such a highly purified state beforehand. Of the numerous techniques for purifying this monomer, the following are noted:

1. Treatment of the monomer over sodium chips or a dispersion of sodium in one

suitable reaction vessel at a temperature between room temperature and about 50 ⁰ C.

2. Washing the monomer with water, treating with granules of potassium hydroxide, and then with Sodium pieces or a dispersion as indicated under (1).

3. Heat the monomer over sodium chips or in a dispersion under a suitable one Fractionation column such as a 30 tray Oldershaw column for boiling and treating the best fractions with sodium pieces or a dispersion in an autoclave with subsequent second treatment in an autoclave over sodium chips.

Instead of sodium as a desiccant in the aforementioned cleaning processes, it is also possible to use Calcium hydride has been found to be used with excellent results.

The. Polymers which are obtained by the process according to the invention are - as already explained - also through an unusual homogeneity with regard to the degree and nature of their structural order marked. The products that are obtained can - if so desired - vary in terms of their molecular weight, which is evident from viscosity measurements in which the intrinsic viscosity values obtained. The differences in molecular weight result by changing the polymerization conditions, for example by varying the Catalyst concentration, the solvent concentration or the degree of purity. In general are the products obtained in accordance with the present invention by inherent viscosity values of about 1.1 to 6.0, indicating molecular weight values up to 3 million.

The inherent viscosity is related to the molecular weight according to the equation of Mark - Ho u wink (please see Macromolecular Chemistry, Vol. 37, pp. 187 to 197, 1960). The formula reads:

M = 7.6 χ 10- ⁴ M ⁰ - ⁶⁰ ,

where [j?] is the intrinsic viscosity and M is the molecular weight means for measurements in benzene. The inherent viscosity (inherent viscosity) at a Concentration of 0.1% is very close to the intrinsic viscosity and is only slightly lower. It so the equation applies

C denotes the amount of polymer in grams per 100 ecm of solution, η _τε1 = the relative viscosity, furthermore

Good Veigen

[??] = Jim C

At the lower end of the inherent viscosity range, ie at 1.1 to 1.8, the tensile strength of the products increases rapidly with increasing viscosity to about 147 kg / cm ² . This is in contrast to tensile strengths on the order of about 70 kg / cm ² or less when the inherent viscosity is below 1.1. Above an approximate intrinsic viscosity value of 2.5, the tensile strength only increases slowly and reaches a value of approximately 210 kg / cm ² at the upper end of the intrinsic viscosity range.

The polymers of the present invention are further characterized by birefringent melting points in the order of about 60 to 70 ⁰ C. This is confirmed by thermomechanical measurements that were carried out on a piece of film, with a static load of 1.4 kg / cm ^{2 being} exerted at the beginning, with the test specimen, namely the film, rotating 1 ° in a jacketed tube C per minute until it broke into two pieces.

The birefringence melting point is determined by measuring the temperature at the complete disappearance of birefringence in a handcrafted specimen takes place on a Kofier heating plate, which is arranged on a microscope plate with a Polymerization and an analysis device is equipped. The specimens are worked in such a way that that birefringence occurs. The correctness of this procedure is confirmed by measurements of diffraction evidenced by x-rays performed on unclaimed films made from a Solution of the polymer, the films being similar before and after exposure Degree of crystal content and thereby the stress exerted by manual processing would. The temperature at which crystallinity disappears, which using a hot plate which is mounted on an X-ray diffraction device is essentially the same as the temperature at which the birefringence of the handcrafted pattern disappears completely, thereby ensuring the validity of this method.

The polymers produced according to the present invention are soluble in benzene and methanol, but insoluble in petroleum ether.

By far the most unusual solubility property of the polymers is their solubility in water at temperatures below 10 ° C and their insolubility above this temperature. At a temperature of around 0 ° C, the polymers swell and finally dissolve completely in water. After ^{this dissolution has taken place at 0} ° C., the polymers remain in the dissolved state up to a temperature of 26 to 30 ^° C.; within this temperature range they then precipitate out of the aqueous solution. The combination of these properties in water with the high tensile strength values and a specific melting point range is unique. Finally, on X-ray diffraction measurements, the polymers show a significant amount of crystallinity, which is expressed by the character of the diffraction rings, which indicate that a substantial amount of the polymer is isotactic. The percent crystallinity, based on an empirical scale derived from measurements of film-like bodies in the X-ray diffraction device, gives percentages of about 10 to 20%.

The following examples serve to further illustrate the subject matter of the invention. If nothing otherwise stated, the amounts given are based on weight.

B e i s ρ i e 1 1

In this and the following examples, procedures and techniques are described at which use a drying cabinet that is filled with a dry nitrogen atmosphere. Specific Details of these techniques are described below.

The polymerization process is carried out according to these! Example carried out in a carefully cleaned reaction vessel, which is equipped with a perforated Crown lock and a self-closing crown lock chuck is equipped. The reaction vessel is alternately evacuated several times and filled again with nitrogen, the vessel intermittently with a hot air generating device was warmed up. The reaction vessel is then placed in a drying cabinet filled with dry nitrogen closed with a crown cap. The injection syringes and that during the reaction Any finishing material that is otherwise required is pretreated in a similar manner. Using an injection needle, the the nitrogen-filled and covered reaction vessel carefully entered 31.0 g of methyl vinyl ether, the cleaned beforehand and dried over bits of sodium

had been net. The technique of transferring the monomer into the reaction vessel involves evaporation of the monomer from the storage container through a closed system that is initially evacuated with subsequent condensation of the vapors at a low temperature (0 to -10 ^c C) through the aforementioned injection needle, which was previously inserted into the reaction vessel had been stabbed. The latter is then placed in a bath of dry ice-acetone at a temperature of -78 ° C, then purified and dried toluene, likewise with an injection needle, 95 ecm is placed in the reaction vessel. The latter had been cleaned beforehand and dried over bits of sodium, the toluene having been taken from bottles which, like the reaction vessel in a drying cabinet, were covered with a cover, nitrogen being injected into the storage vessels immediately before the injection into the injection syringe. In the solution of the monomer in toluene, the temperature is set to -78 ⁰ C, then a (]} catalyst solution was again through a syringe 1.40 ecm input consisting of boron trifluoride dissolved in 1,4-dioxane-Diäthylätherat, wherein 0.11 g of catalyst are dissolved in 1 ecm of 1,4-dioxane. The molar ratio of 1,4-dioxane to boron trifluoride diethyl etherate is about 14: 1. Both the diethyl etherate and the dioxane used in reserve to prepare the catalyst initially became strong The bottle containing the catalyst is also pressurized with dry nitrogen and both this bottle and the reaction vessel are equipped with a device which enables a flowing stream of nitrogen to be passed over the crown caps , with simultaneous injection or removal of reagents with a hypodermic syringe in an essentially moisture- and air-free Surroundings. Immediately after the catalyst has been injected, the reaction vessel is shaken rapidly and then left to stand overnight. The next day the contents consist of a clear, non-flowing gel at a temperature of -78 ° C. Methanol containing ammonia is then injected to dampen or quench the reaction, and enough toluene to make the solution manageable ( the total reaction time is about 20 hours). The contents of the reaction vessel are then carefully poured into suitable tubs and the solvent is pumped off. The resulting polymer consists of a clear, firm and strong and elastomeric, non-sticky film which, after some stretching by pulling, exhibits reversible extensibility. The yield of polymer is 28.3 g, which corresponds to a 91.3% conversion. The intrinsic viscosity of 0, l% solution of the product in benzene at 25 ⁰ C using a Ubbelohde viscometer is 3.26. For comparison, it should be stated that the intrinsic viscosity is 3.33 and the viscosity number (= reduced viscosity) for a 1% solution is 9.07. In this example, the amount of catalyst used is 0.21 mol percent, based on the amount of monomer present, the ratio of methyl vinyl ether in grams of 6s to toluene in cubic centimeters is 1: 3 was carried out. The melting point is the temperature at which the birefringence disappears; it was determined to be 61 to 64 ° C. A thermomechanical measurement was carried out on a piece of film with a static load of initially 1.4 kg / cm ² , the temperature being increased by 1 ° C. every minute. At a temperature of about 6O ⁰ C, the film broke into two pieces.

This polymer is soluble in benzene and methanol, but insoluble in petroleum ether. A sample of the polymer was placed in water at room temperature, but no dissolution occurred. The temperature was then slowly lowered, ^{the polymer swelling rapidly at 0 °} C. and completely dissolving in the water. A 2% aqueous solution of the polymer was found to be unusually viscous. An aqueous solution of the polymer was also heated to about 40 ° C. and the resulting polymer precipitate was separated off, dried and pressed into film form in a Carver press. This precipitation technique separates the catalyst from the polymer. The catalyst-ammonia complex can also be removed by filtering off the toluene solution. The polymer is then separated from the aqueous solution, dried and brought into film form in a Carver press. The X-ray diffraction pattern of unclaimed film shows a significant amount of crystallinity as evidenced by the character of the diffraction rings. The tensile strength measurements of the film showed a value of 137.9 kg / cm ² and an elongation of 16.8 cm (based on a 2.5 cm clamp separation on the Instron device) *). The stress-deformation curve had no yield point. When processed on a two roll mill, the polymer formed a solid rubber crepe. The reaction time was about 20 hours.

Example 2

Example 1 was repeated with the modification that the methyl vinyl ether monomer used although it was highly purified as in Example 1, but then in its absence for about 1 month of a preservative has been stored at a temperature of about -10 ° C.

The reaction was carried out exactly as described in Example 1 for 21 hours at a temperature of -78 ° C. The reaction product was then quenched with methanolic ammonia, diluted with toluene, the solution filtered off and the solvent pumped off. The resulting product consists of a clear, colorless and solid elastomeric film and of thread-forming material, the yield is 90%. The inherent viscosity, which was measured similarly to that described in Example 1, is 1.84; the birefringent melting point is 65 to 67 ° C. The tensile strength is 142.1 kg / cm ² and the elongation at break is 16.8 cm, starting with a 2.5 cm pinch separation on the Instron device. The 100% modulus is 21 kg / cm ² , the 200% modulus is 23.8 kg / cm ² , and the 300% modulus is 25.2 kg / cm ² . These values are an indication that the material is rubber-like in character.

*) "Instron device", i.e. H. Apparatus for measuring material properties manufactured by Instron Corporation.

209 542/529

There is no yield point on the tensile strength curve. A thermomechanical measurement that is like was carried out in example 1, results in a value of 62 ° C.

Example 3

The procedure according to Example 1 was repeated using 21.4 g of methyl vinyl ether monomer, 64 ecm of purified toluene and 0.10 mol percent of the same boron trifluoride diethyl etherate - dioxane - catalyst combination (each 1 ecm of dioxane solution containing 0.104 g of boron trifluoride diethyl etherate) . The reaction was quenched after 23 hours and worked up as described in Example 2. The yield consisted of 19.4 g of a solid, elastomeric film former that is clear and colorless. The birefringence melting point of a hand-drawn film is 69 to 70 ^° C. The intrinsic viscosity of a 0.1% benzene solution is 4.90 and the intrinsic viscosity 5.15. The product shows a relative crystallinity scale value of 14.6% on the basis of X-ray crystal investigations. The tensile strength measurements and the extensibility measurements were carried out as in the previous examples, a tensile strength of 186.2 kg / cm ² and an extensibility of 945% being determined. The solubility properties of the polymer are similar or the same as those of the products of the previous examples.

Example 4

The procedure of Example 1 was repeated again using 27.7 g of methyl vinyl ether and 81 ecm of purified toluene. The catalyst system again contains 0.104 g of boron trifluoride diethyl etherate per cubic centimeter of dioxane solution, as in Example 3, and is used in an amount of 0.15 mol percent, based on the monomer. After a stay of 5 hours in a cold bath at -78 ⁰ C, it was found that the reaction solution had become very viscous after 24 hours the polymerization was quenched, and, as in Example 2 loading

wrote, worked up. The product obtained appears physically like the products of the previous ones Examples, the yield was 90% and the birefringence melting point 63 ° C; the inherent viscosity was 4.94 in benzene at a 0.1% strength

Concentration, the relative X-ray crystallinity scale gives a value of 12.8%, the tensile strength is 177.1 kg / cm ² and the percentage elongation is 1028%. A relative crystallinity density scale, based on 0%, which value

a tightness of 1.0378 and, based on 100%, which correspond to a tightness of 1.1824, gives a value of 12.5%. The 100% value is from calculations based on X-ray diffraction measurements derived, with a seal

Gradient rubric was used for leakage measurements. The polymeric film obtained is strong, firm and easy to pull in the hand. After this pulling process, it is elastomeric, as if through its reversible elasticity is shown. Fer-

The product obtained is not sticky.

Example 5

In the following examples, which were carried out in one set and at the same time, was the procedure of Example 1 was repeated, the reaction time being about 20 hours and the same catalyst content was used. The reactions were quenched as in Example 2 and worked up. In these examples, varying molecular amounts of catalyst, based on the monomer content. The terms of these examples are in the Table I below, which also gives the properties of the polymer obtained.

Table I.

Test example 5

g methyl vinyl ether / cm ³ toluene

Mole percent
BF ₃ etherate
in 1,4-dioxane

(0.1% Te "nzol) yield tensile strenght Percent
tuale
strain (25 ⁰ C) (in %) (in kg / cm ² ) (in %) 0.95 87.5 101.5 817 3.00 99 163.8 937 1.65 100 165.6 992 1.22 100 116.9 955

% Relative
Crystallinity

after

X-ray scale
(in %)

Double

refractive

melting point

( ⁰ C)

A.
B.
C.
D.

1/3
1/3
1/3
1/3

0.06
0.20
0.50
1.0

18.4
16.7
19.6
17.9

68
60.5
65
62

Example 6

In the following test examples 6 A to 6 E carried out in one set and their conditions and results are summarized in Table II, the procedure of Example 1 is been repeated, but this time boron trifluoride diethyl etherate in an amount of 0.104 g per cubic centimeter of dioxane solution was used. The procedure was the same as in Example 2. The catalyst concentration was constant at 0.20 mole percent based on the weight of monomer, held, but the ratio of solvent to monomer was given in Table II Way varies ..

Table II

g methyl vinyl Mole percent yield Reaction Ή own % Relative tensile strenght Percentage test ether / cm ³ toluene catalyst length of time (0.1% benzene) Crystallinity strain example 6 (in %) after (in kg / cm ² ) 1/20 0.20 7.6 (in hours) (25 ° C) X-ray scale A. 1/20 0.20 33.0 22nd 0.173 211.4 829 ' B. 1/10 0.20 46.0 46 1.754 16.6 177.1 881 C. 1/10 0.20 81.5 22nd 1.680 18.2 194.6 881 D. 1/3 0.20 96.5 46 2.127 16.5 194.6 1104 E. 22nd 2.80 12.3

From Table II just given it can be seen that with a ratio of monomer in j grams to toluene in cubic centimeters of 1: 3 an j excellent yield of a very good product j is received within 22 hours. This is in agreement with the results of the previous one Examples. With a ratio of 1:10 i]) after 22 hours the yields are satisfactory Product low. After 26 hours of reaction, the product is better and so is the yield.

With a ratio of 1:20 it will be after 22 hours very little product of little value received. After 46 hours, however, one obtains at this ratio is an excellent product, but the yields are proportionate are small, this is due to the fact that the condition of the ratio of monomer to solvent is already approaching the upper maximum limit, which is preferred in the present invention is to be considered.

As the solvent to monomer ratio increases and the preferred upper maximum limit almost reached or even exceeded, the main disadvantage of the process is poor yields and very long response times. It should be emphasized, however, that the product which In doing so, what is eventually obtained is still commensurate with the products that are among the preferred Process conditions are obtained.

Example 7

The procedure of Example 1 was repeated, but this time with a catalyst content of 0.104 g per cubic centimeter of solvent was complied with. The reaction time was for all test examples 7 A to 7 E, which were carried out in one set, 22 hours. The results are summarized in Table III below.

Table III

test g methyl vinyl Mole percent yield (0.1% "ί§βηζοΙ) % Relative
TV " 4. 11 * 'Λ." L tensile strenght Percentage example 7 ether / cm ³ toluene catalyst (in %) (25 ° C) Crystallinity
according to the X-ray scale (in kg / cm ² ) strain A ' 1/3 0.20 92 2.53 12.0 177.1 965 B. 1/10 0.14 35.9 2.11 14.5 193.9 985 C. 1/10 0.20 52.3 1.98 14.1 172.2 ' 1020 D. 1/10 0.50 97.5 1.77 14.4 154.7 941 E. 1/10 1.00 99.2 1.29 14.7 1015

From the information just given it can again be seen that solvents are used at higher ratios to monomer, the yields are lower when the catalyst concentrations drop, however, the products are still quite satisfactory.

Example 8

60

In Examples 8 A to 8 E described below, which were carried out in one sentence, the procedure of Example 1 was followed. The main solvent is toluene, the ratio of monomer in grams to toluene in cubic centimeters being 1: 3. In test example 8 A, the catalyst consists of pure boron trifluoride diethyl etherate (catalyst solution A). In Examples 8 B to 8 E, the catalyst used consists of boron trifluoride diethyl etherate in dioxane with a content of 0.102 g of boron trifluoride diethyl etherate per 1 ecm of dioxane (catalyst solution B). In Example 8 B, the catalyst combination is used as such. In the examples 8 C to 8 E, dioxane is added separately to methyl vinyl ether in toluene solution at -78 ° C, by dioxane concentrations of 43, 70 or more than 100 moles of dioxane per mole of boron trifluoride diethyl etherate to adjust. In Example 8D, this ratio is 15: 1. The total response time is in all examples 20 hours. The ratios and results are given in Table IV below specified.

Esteemed
Volume
percent on
1,4-dioxane
in total
solvent 13th Mole
percent
Kataly
sator Kataly
sator
solution 1,570,707 (0.1% benzene)
(25 ° C) tensile strenght
in kg / cm ² elongation
(in %) 14th - Birefringence
softening point
(° C) 0 0.20 (A) 1.10 Weaker
Movie Relative
Crystallinity
after
X-ray scale
(in %) - / 38 'to 43 test
at
game 8 1.4 Moles of dioxane /
Moles of BF ₃
Etherate 0.20 (B) Table IV 1.95 154.7
1200 7.2 62 to 63/57 A. 3.0 0 0.20 (B) Out
prey
(in %) 2.27 178.5
1191 12.4 not measured B. 6.0 15/1 0.20 (B) 88.3 2.04 169.4
1169 12.0 not measured C. 16.4 43/1 0.20 (B) 98 1.98 171.5
1220 13.6 not measured D. 70/1 94.8 12.5 E. over 100/1 90.5 83.5

From the data given above, the products of the present invention can be clearly seen, which further

lent that one is described above when using boron trifluoride, and also in the examples,

Diethyl ether alone is a relatively good result. The test examples 8 B to 8 E

loot of polymer, which shows the outstanding properties of the inven-

Properties is completely different compared to products manufactured according to this.

Example 9

The procedure of Example 1 was repeated, again using a whole set of Test examples at a temperature of -78 ° C and a catalyst concentration relative to Monomer was used, which is given below. The catalyst (a) has a content of 0.104 g of boron trifluoride diethyl etherate per 1 ecm

Dioxane in test example 9 A and (b) a content of 0.063 g of boron trifluoride diethyl etherate per 1 ecm Toluene in Test Examples 9 B, 9 C and 9 D. The ratio of monomer to toluene is for each Test example 1 g / 3 ecm and the reaction times 23 hours. The proportions and results are in given in Table V below.

Table V

test
example 9 Kataly
sator
solution Mole percent
Catalyst,
relative to Out
prey Veigen
(0.1% benzene) tensile strenght
in kg / cm ² elongation 100% module
in kg / cm ² ,
200% modulus % Relative
Crystallinity
according to the X-ray scale Birefringence
melting point (a) Monomer (in %) (25 ° C) (in %) (in kg / cm ² ) ( ⁰ C) A. 0.1 95.2 3.32 184.1 18.4 12.6 65 (b) 1105 36.4 B. 0.2 95.4 1.20 38.5 16.8 8.4 55 (b) 720 21.0 C. 0.1 82.3 1.40 72.8 18.2 9.4 58 • (b) 1039 23.1 D. 0.01 4.5 0.55 not measured not measured not measured not measured

The data just given show that in the absence of dioxane the polymer product is defective Has viscosity and tensile strength properties and that at equivalent catalyst concentrations the yields are low.

Example 10

The procedure of Example 1 was repeated in one sentence using various catalyst concentrations given in Table VI. In test examples 10A, 10B and IOC the catalyst consists of boron trifluoride diethyl etherate in toluene (content 0.104 g / ccm solution) and in test examples IOD, 10E and 10F of boron trifluoride diethyl etherate in dioxane (content 0.105 g / ccm solution). The monomer / toluene ratio is 1 g / 3 ecm; the temperature is from -78 ⁰ C and the reaction time 19 ¹ Z ₂ hours.

Table VI

test
example Catalyst carrier Volume percent
Kataly yield (0.1% 1ie "nzol) train
strength Percentage
strain 1303 Prerelative
Crystallinity
after Viscosity after 2 hours 10 sator (in %) (25 ° C) in kg / cm ² ) 1121 X-ray scale A. toluene 0.20 83.4 1.37 not measured 1099 7.7 non-flowing gel B. toluene 0.10 84.0 1.65 102.2 1125 7.6 the same C. toluene 0.05 83.2 1.69 95.2 not measured 8.8 the same D. 1,4-dioxane 0.20 100 2.89 159.6 • 12.3 no viscosity E. 1,4-dioxane 0.10 ioö 3.47 200.9 11.6 the same F. 1,4-dioxane 0.05 97.5 4.90 the same

Example (comparative experiment)

This example describes a polymer which, using a catalyst system of the Prior art was produced.

The technique or procedure of Example 1 was repeated, with the one modification that the catalyst consists of a solution of boron tri-

fluoride diethyl ether in diethyl ether consists: (content 0.053 g boron trifluoride diethyl ether prc Grams of catalyst solution). The temperature of the polymerization is -78 ° C and the reaction time 19.5 hours. The ratios and results are given in the following table.

Mole percent
BF ₃ etherate
in diethyl ether »! Eiaen
(0.1% benzene)
(25 ° C) Table VII tensile strenght
(in kg / cm ² ) Percentage
strain % Relative
Crystallinity after
X-ray scale test
example 11 0.02
0.15 0.82
0.89 yield
(in %) 53.2
42.0 533
453 12.4
14.0 A.
B. 23
91

example

The procedure of Example 1 was repeated using 2 · boron trifluoride

ratio monomer / toluene is 1 g / 3 ecm; the reaction time is 21.5 hours and the temperature

Dioxane complex, dissolved in dioxane as a catalyst 40-78 ° C. The catalyst concentration was then sator (content 0.099 g complex / g solution). The behavior varies as indicated in the following table:

Table VIII

test
example 12 Mole percent
catalyst V own
(0.1% benzene)
(25 ° C) yield
(in %) tensile strenght
(in kg / cm ² ) Percentage
strain % Relative
Crystallinity after
X-ray scale A.
B. 0.28
0.14 2.51
3.48 100
97.5 120.4
167.3 1371
1244 9.7
10.7

Example 13

The reaction technique of Example 1 and the isolation technique of Example 2 were repeated with the change that the following temperatures have now been maintained:

13A -30 ° C. 13B -46 ° C. 13C -50 ° C. 13D -55 ° C. 13E -60 ° C. 13F -70 ° C. 13G -100 ° C.

55

60

The product according to 13 A is amorphous and white no significant strength. At temperatures from -40 to -50 ° C the products are similar to v, that of Example 1, but of lower tensile strength. Products 13 D to 13 G are excellent

B e i s ρ i e 1 14

Example 1 was repeated again using the following catalyst cores centrations:

14A 0.01 mole percent 14 B 0.03 mole percent 14 C 0.05 mole percent 14 D 0.08 mole percent 14E 1.5 mole percent

209 542/52 =

The products have excellent properties, with 14A and 14 B the yields are somewhat lower than 85%.

Example 15

Example 1 was repeated again with the modification that instead of 95 ecm of toluene the the following quantities were used:

15A 15.5 ecm "" ", / ^

15B 31.0 ecm, ■ '__ .Γ

15 C 62.0 ecm

15 D 775.0 ecm

The products according to 15A through 15D are all excellent, however the yield at 15D is quite good low.

Example 16

Example 15 was repeated using twice the concentration of catalyst. The yield is then comparable to that of Example 1.

Example 17

This example is carried out at -78 ° C. in the same way as described in Example 1, with the modification that the catalyst system used consists of a slurry of solid 2 BF ₃ · dioxane in toluene. 0.0966 g of catalyst were present in each case in 1 ecm of the total solution. The reaction solvent is toluene

^ io and the ratio of methyl vinyl ether in grams per toluene in cubic centimeters is 1/3. An aliquot of catalyst slurry, equivalent to 0.1 mole percent 2 BF ₃ • dioxane based on monomer, was injected into a reaction solution having a temperature of -78 ° C. The catalyst slurry was found to be insoluble in the reaction solution. The reaction time was 21.5 hours at -78 ° C. Work-up was carried out as described in Example 2 and gave a yield of 91%. The inherent viscosity (0.1% solution in benzene) at 25 ° C is 2.37; the percentage relative crystallinity according to the X-ray scale is 10.7%, the tensile strength 161 kg / cm ² and the percentage elongation 1299%.

Claims (1)

Claim: Process for the preparation of homopolymers of methyl vinyl ether in an inert solvent at low temperatures by means of boron fluoride or its complex with ether, thereby characterized in that in the presence of 1,4-dioxane and at a temperature between -100 and -40 ° C polymerized. It is known that alkyl vinyl ethers and especially ethyl vinyl ethers react with acidic substances Catalysts can be polymerized, being generally liquid or semi-solid polymer products arise. The methyl vinyl ether polymers prepared according to such procedures as described in U.S. Patents 2,104,000, 2,104,001, and 2,104,002 are products of relatively low value Molecular weights that are soluble in water at room temperature. One of the unique properties of these homopolymers is their solubility in water at relatively low temperatures; H. below Room temperature, and their insolubility at elevated temperatures. Such products were used as modifiers proposed and used for various materials including numerous synthetic and natural resin products, for the purpose of improving numerous different Properties of such natural and synthetic resin materials such as adhesive force, the Plasticity and the speed of steam penetration. However, these polymers are evident especially in the homopolymer form unsuitable for numerous applications in which it dimensional stability is important, so they cannot be used to make objects that are self-supporting, such as dimensionally stable films and fibers. The production of dimensionally stable polymers from methyl vinyl ether was first introduced in the USA patents 2,616,879 and 2,653,923 which disclose polymerizations using a boron fluoride-ether complex as a catalyst system, at extremely low temperatures in the range of about -30 to about -70 ° C, but not underneath, is being worked on. These polymerization temperatures are quite different from the temperatures which were previously observed, namely those of a little above about -10 ° C. The Products made at these very low temperatures using the boron fluoride etherate complex catalyst system are produced, are dimensionally stable cheek-like polymers with a slightly higher Molecular weight than the products made according to the earlier methods. These former Similar to the bodies produced earlier, polymers are soluble in water below about 35 ° C, however, insoluble in water above this temperature. 'Unlike the earlier products, these are Homopolymers appear to be partially crystalline, eliminating to some extent the presence of isotactic material is displayed. Recent developments in this area have suggested suitable methods of manufacture of relatively high molecular weight amorphous homopolymer methyl vinyl ether such as this for example in U.S. Patent 3,022,280, and on the other hand for the production of homopolymer relatively high molecular weight which is highly crystalline and insoluble in water; the Manufacture of the latter type is set out in U.S. Patents 3,014,014,3,025,281,3,025,282 and 3,025,283. Here, reaction products of metal salts are used as a general class, catalytic material, including the bodies commonly referred to as Ziegler catalysts. Further are the polymers made according to the procedure disclosed in the latter patents are characterized by the fact that it is a heterogeneous mixture of crystalline and not crystalline polymers with a wide molecular weight distribution. It has now been found that homopolymers of methyl vinyl ether of extremely high molecular weight can be produced by a process in which products are obtained that are not only dimensionally stable are and are particularly suitable for the production of films, fibers and the like with high tensile strength, but it is also characterized by unusual solution properties, which are described below ■ are, distinguish, in connection with further unique Properties. So you can use it to make films and fibers with unusually high tensile strengths and extensibility can be used. So they also show an extraordinary structure. homogeneity. Finally, the products made according to the teachings of the present invention are progressive only has a narrow molecular weight distribution. The process of the present invention which results in homopolymers involves polymerization of monomeric methyl vinyl ether in extremely pure form and under carefully controlled conditions when using a special catalyst system. While so far it is known, boron trifluoride dialkyl etherate as a catalyst in the polymerization of methyl vinyl ether, as described above. to use, it has now been found that boron trifluoride or its complex with ether in combination with 1,4-Dioxane is more unusual if the specific conditions described below are complied with for the recovery Homopolymer leads. According to a preferred embodiment, highly purified materials are used and no interfering materials and in particular no water are tolerated; It is also carried out in an inert atmosphere and an inert diluent is used as a carrier for the monomer. This thinner is of great advantage because from some point the polymerization reaction is exothermic.
It has also been found that it is advantageous to use such a diluent in a certain maximum concentration in order in turn to achieve optimal properties of the homopolymer. Finally, the catalyst concentration is not of critical importance, but here too certain limit values must be observed in order to achieve the best results. As already stated above, the catalyst system consists of a boron trifluoride-dioxane combination