DE2035362C3 - Process for the production of moldings from purified saponification products of ethylene-vinyl acetate copolymers - Google Patents

Description

Adding a fouling agent, such as water, to the amount of water that the methanol solution of this Solution, by steam distillation, as given in saponified ethylene-vinyl acetate copolymers U.S. Patents 2,386,347, 2,399,653 and blends must be within the range in 2,403,464, or by cooling the saponified copolymers in solution Solution. 5 at a temperature between 35 ° C and the boiling point

In the case of the cooling method, the sealing temperature of an aqueous methanol mixture is after solution containing the solution, the loss of the addition of water has not yet occurred due to gel formation such high values of polymer are deposited during the separation operation. That means that after the such as more than 5 percent by weight, and the isolated addition of water to the saponified copolymer always Polymers are extremely fine in particle size and still remain dissolved in the aqueous methanol solution prior to which there must be a substantial loss of the polymer.

When isolating, washing and drying vir- When this saponified copolymers with the solution

is caused. On the other hand, although the coagulation bath comes into contact with the method, if a precipitant is added to the solution of the coagulates with a saponification product, the loss of copolymer is low within a few minutes with minimal loss of polymer in the separator separation operation, the copoly- formation process and leads to microporous films or mere agglomerates due to its strong fibers, which can be easily handled.
Cohesive strength easy and difficult to effectively dissolve the copolymer at a high temperature

Way to wash and dry, if it has not been cooled before and after, so it reaches a temperature is ground or pulverized, and the resulting 20 in which the polymer is partially deposited, dry product reads in the form of a powder with this temperature, however, does not necessarily correspond to lower apparent density of about 0.2 to 0.4 depending on the solution temperature of the polymer. In this before. When this powder the molding or polymer solution occurs a so-called »delayed Melt spinning is often a deposit. Hence the designation means Vent to remove what is needed in the molten »5» to dissolve the saponification product Polymers present air required, and water «an amount of water that is necessary for the are therefore rods for use in melting polymers to keep them in an undeposited state, spin, cast and preform before films the necessary to release the saponification product or threads can be made. The amount of water basically depends on the ethylene

The invention is based on the object of a content and the degree of saponification of the copolymer, a method for producing moldings which are heat-resistant to the polymer concentration of the saponified copoly, guie mechanical toughness and meren and the temperature of the solution.
have high elasticity, made of purified versi- In the most effective embodiment of the inven-

Ethylene-vinylsate is used for the production of ethylene-vinyl acetate copolymers according to the process to get out of the solution. 35 acetate copolymers by adding an alkaline

According to the invention, this object becomes a 25 to 50 percent by weight catalyst solved that one methanol solution of the ethylene-vinyl acetate copolymers

1. The above-mentioned saponification water ^ren _r ⁱⁿ "" fm molar ratio of 0.005 to 0.5, ser based admixed in such an amount that the * ^{u in} function of the composition of this limit of the gel formation and the deposition of the polymer ⁴ ° in the copolymer present acetic saponified copolymer from the solution with acidic residues saponified, which if necessary can take place after the temperature of this solution is not yet concentrated. Then an amount of water is sufficient that is necessary for the saponification

2. the resulting aqueous-methanolic solution of the copolymer is dissolved saponified copolymer at the temperature of this solution in a water ⁴⁵ ; ° ^{the one} f. Such amount of water added from or a mixture of methanol and water is enough to extrude the separation of the saponified product existing coagulation bath, which ^{prevent a z} "so that an aqueous methanol solution has a lower methanol concentration than that obtained, the 15 bs 45 percent by weight, preferably extruded solution, ^{20 to 40} percent by weight of this saponify

3. deformed the saponified copolymer, ^{containing 5} ° copolymers. The solution will be through afterwards

4. removing the moldings obtained from ^eme slit having a desired thickness for the sodium acetate or potassium acetate and comparable washing out a sheet or film suitable length in a Koagubliebenen alkaline catalyst lationsbad solution extrud.ert or it is a film and dries solution ^r of the saponification product of a thickness of

55 1 to 10 mm formed on a flat plate and

In the method according to the invention, the shaped bodies are then formed out of the film in a coagulation solution in washing, drying and the like, or the solution of the saponification product becomes Operations easy to handle, and it arises when through a nozzle with an opening diameter that Separation process only a very small loss of polymer for the desired diameter of a thread. 60 is suitable, extruded into a coagulation solution, the preferred concentration of the invention forming a strand of 1 to 10 mm diameter treated ethylene-vinyl acetate copolymers is located. When the concentration of the copolymer in in the range of about 25 to 50 percent by weight. That the aqueous methanol solution is too low, it is applied to carry out the saponification Mol- impossible, the copolymer in the form of a film or ratio of an alkaline catalyst to the 65 of a strand to coagulate, if, on the other hand, the Copolymers is in the range from about 0.005 to 0.5, concentration is too high, the product shows deficiency based on the number of moles of acetic acid residues in porosity. Hence a concentration of this is verdem Copolymers are included. Soap copolymers in the aqueous methanol solution

5 6

in the range from 15 to 45 percent by weight desirable weight percent methanol and 70 percent by weight

worth. Water at 15 ° C. The coagulation of the

The coagu-extruded solution to be used according to the invention took place within 7 minutes

lation bath solution is a mixture of methanol and complete. It became a microporous sheet of the

Water or water alone is desirable. Particularly 5 dimensions 30 cm x 12 cm x 2 mm obtained,

A mixture of methanol and, since the plate had a microporous structure, was well suited

Water that contains 10 to 50 percent by weight of methanol they are easy to wash out and dry,

contains. It is necessary that the methanol concentration after washing with water to remove

tration in the coagulation bath solution equal to the sodium acetate and after drying had the

or lower than that of the extruded aqueous sheet obtained a tensile strength of 23 kg / cm ² ,

Methanol solution is. A higher concentration of methanol - an elongation of 310% and an apparent density

Tration is undesirable because it results in a loss of about 1.0.

saponified Copolysierem in the deposition By cutting this plate with the help of a Process in the coagulation bath solution is increased. Pelletizer, pellets are obtained which are used for The temperature at which the solution of the saponified 15 production of foils or threads are suitable. Copolymers with the coagulation bath solution in The loss of copolymer in the separation report should be lower than the manuring process in this case was 0.2 weight temperature lie at which the copolymer in percent.

Coagulation bath solution is insoluble. A lower range is ρ '■ e 1 2

Temperature is desirable to avoid loss at 20

the deposition process as possible _e ering to keep. _ 100 g of an aqueous methanol solution of saponified

A temperature of 10 to 30 ⁰ C is generally ethylene-vinyl acetate copolymers, which according to the im

preferred. The method described in Example 1 obtained in the manner described has been obtained

Films or sheets and strands are microporous, var, was through a nozzle of 5 mm diameter

easy to wash, and the loss in the exhaust 25 in 1 kg of the compound described in Example 1 coagulation

separation process is a maximum of 0.8 weight bath solution extruded. The copolymer was in

percent or less than 1/2 of the loss deposited and coagulated in the form of a strand,

conventional procedure in which the solution is being required 4 minutes for coagulation

is merely cooled occurs. With a coagu ware. The product obtained in the form of a strand

lation bath solution that was microporous and easy to wash out at a temperature of 30

is ^{kept above 50 0} C, it is impossible, after drying with the help of a pelletizing or

to carry out the method according to the invention. Tableting device in suitable for deforming

The pellets or tablets are cut up in the manner indicated in the form of a film. The apparent

Product obtained or plate can be in the original density of that in the form of tablets

borrowed shape or after cutting into bars 35 product was 0.99. During the deposition

or pellets are washed and dried. A loss of 0.5 percent by weight of the operation occurred

The product in the form of a strand may contain copolymers.

also in this form or after cutting Example 3
washed in pellets and dried.

The invention is detailed below under 40 An aqueous methanol solution of the saponified ethylene reference on the following examples described- vinyl acetate copolymers, which are prepared by the method of ben. Example 1 was obtained, was on a B e i s o i «1 1 glass plate with 3 mm frame height and a size

of 15 x 15 cm and immediately poured into 400 g of a

40 parts of ethylene-vinyl acetate copolymer immersed in a coagulation bath solution maintained at 45 ° C at 30 ° C, content of 32.5 mole percent ethylene units, 70 parts of 10 weight percent methanol and 90 weight percent methanol and 4 parts caustic soda became weight percent water. The coagulation took place in a solution mixed with one another and for 15 minutes. A sheet of soaps of this copolymer having the conventional dimensions of 15 cm x 15 cm x 1.2 mm was obtained, the soaping method was microporous and easy to wash out for 3 hours at 60 ° C, and one was heated. During the progress of the reaction tensile strength of 15 kg / cm ¹ , an elongation of, a mixture of 12 parts of methyl acetate and 410% and an apparent density of 0.89 was had. 5 parts of methanol are removed from the reaction system. The loss of copolymer when <! Em is deposited. The degree of saponification of the saponified ethylene process was about 0.4 percent by weight.
Vinyl acetate copolymers in the obtained methanol 55. .
solution reached 98.5 mole percent. be 1 s ρ 1 e I 4

The solution thus obtained was then prepared by heating 200 parts by weight of a copolymer of 28 mol.

so concentrated that the content of this copoly- percent ethylene, 70 mol percent vinyl acetate and

kidneys was 40 percent by weight. 2 mole percent acrylic acid was in 400 weight

26 parts of water were dissolved at 6O ⁰ C into 100 parts of the 60 parts of methanol, mixed in the 15 Gewichtsteifc kaukonzentrierten solution. The saponified static soda were added and reacted at 6O ⁰ C during ethylene-vinyl acetate copolymers in the 2 hours obtained. The saponification solution obtained was not deposited under the specified conditions which had a degree of saponification of 96 mol percent of copolymer concentration, degree of saponification and 28 mol percent ethylene and 2 mol percent acrylic temperature. acid units contained, was to a content of

100 g of the solution obtained were ^{concentrated from a slot 5 to} 35 percent by weight of this copolymer, a nozzle 3 mm thick and 30 cm wide in 1 kg of a 100 parts by weight of this concentrated copoly.

Coagulation bath solution was extruded, 25 parts by weight of water were added to the 30 gel solution.

so that an aqueous methanol solution of the copolymer at a temperature of 60 "C. 100 g of this copolymer solution were passed through a slot nozzle of dimensions 30 cm x 4 mm is extruded into a coagulation bath solution that consists of 20 percent by weight Methanol and 80 percent by weight water and was kept at 25'C. The full Coagulation was carried out in 13 minutes. A 3 mm thick plate was obtained. This The plate had a microporous structure and was easy to wash free of sodium acetate and to settle Wash out and dry easily handle. The loss of copolymer in the deposition process was 0.3 percent by weight. The record was cut into pellets or tablets before drying with the aid of a tablet machine and then cut dried. The plate was also cut into similar tablets after drying. the apparent density of the product was 0.95.

Example 5

100 g of an aqueous methanol solution of ethylene vinyl alcohol copolymer, which while complying with a Degree of saponification of 97.2 "" by treating Ethylene-vinyl acetate copolymer with a content of 38 mol percent ethylene units according to the method of Example 1 was obtained through a slot nozzle with the dimensions 30 cm x 3 mm in

ίο a coagulation bath solution of 15 percent by weight Methanol and 85 weight percent water maintained at 14 ° C, extruded. Through full Coagulation within 6 minutes resulted in a plate that was microporous and extremely light

is of sodium acetate and similar impurities was to be washed free. This plate had a tensile strength of 25 kg / cm * and an elongation of 290%. 0.3 percent by weight of the polymer was lost in the deposition process.

Claims (5)

1 2 vinyl acetate copolymers of the general formula Claims: {pj ^ (CH, CHOCOCH3) r (CH8CRRO1. 1. Process for the production of shaped bodies in which R is a hydrogen atom or a MetbyJgruppe from purified saponification products of ethylene and R 'is a methyl or vinyl group or - COOR, vinyl acetate copolymers from the solution, the - C ₆ H ₅ , - C or - CN denotes the ratio by known saponification of ethylene-vinyl- (Y + Z): X within the range from 1.5: 1 to acetate copolymers of the general formula 3: 1 and the ratio Z: Y within the range from 0-1 to 0.1: 1 until reaching a (C ₂ H ₄ ) X (CH ₂ CHOCOCH ₃ ) F (CH ₁ CRRO ₈ , _{10 se} ifungsgrad of more than 90 mole percent in counterpart in which R is a hydrogen atom or a methyl part of methanol with the help of an alkaline kata group and R 'a Methyl or vinyl group or lysators. - COOR, - C ₆ H ₅ , - C or - ON mean, the aim of the invention is to produce purified ethylene the ratio (Y + Z) : X within the range of vinyl alcohol copolymers with good film formation from 1.5: 1 to 3: 1 and the ratio Z: Y within 15 or fiber-forming properties. The aim of half the range from 0: 1 to 0.1: 1 is until the invention is also to make pellets or chips from reaching a degree of saponification of more than ethylene-vinyl alcohol copolymers accessible to 90 mol percent in the presence of methanol with the somewhat higher apparent specific help of an alkaline catalyst produced density of about 0.7 to 1.2 and microporous structure, characterized by having 20 and for the production of foils, plates that one or threads according to various processes, in particular -,. ... WT 1 »λιγ ■ other after the casting process or the melting 1. the obtained saponification water in. ^{im <} - "" * · "" · »♦""/-" «« i, ™ ,, _w · i_ j η. ·, -. Spinning process from the saponified copolymer mixed in such a quantity that the limit spinnvenanreii, au » rj the gel formation and the deposition of the are suitable. _V ; ™. "*," R saponified (! «polymerisates from the solution at * fs, is known saponified Athyjen-V.nylacetat-Co- the temperature of this solution has not yet been ^{polymerized by} saponifying ethylene-vinyl acetate is achieved copolymers with an alkaline catalyst, such as 2. the obtained 'aqueous-methanolic solution of sodium hydroxide or potassium hydroxide in counter-saponified copolymers in a from Wasser ™ * of lower aliphatic alcohols such as or a mixture of methanol and water 3 ° methanol or ethanol. After the coagulation bath consisting extruded to the gewünschter1 degree by a lower methanol concentration has the saponification g ^{efuh was rt w} '. ^{lrd the e} ™? ^Ite ethylene vinyl alcohol as the extruded solution, copolymers .shear what, e.g. 3. the saponified copolymer deformed, steam-proof. lation to remove the lower al.pha- 4. The moldings obtained can be eriojsen to remove alcohols from 35 tables of washing of the remaining poly-sodium acetate or potassium acetate and the meren and drying.
Remaining alkaline catalyst from. It is also known that foils washes and dries plates ^{or threads from the} saponified copolymers obtained by casting processes or by melt-spinning, 2. The method according to claim 1, characterized in that 40 wet or dry spinning processes are obtained, draws that the aqueous; -methanolic These methods are for example in the USA. solution of the saponified copolymer by patents 2,386,347, 2,399,653, 2,403,464 and Addition of water to the saponification solution is described in one of British Patent 1,120,189. Temperature between 35 ° C and the boiling point. This saponification is generally caustic the aqueous methanol solution produces. 43 Soda or sodium hydroxide as an alkaline catalyst 3. The method according to claim 1 or 2, characterized used sator. The predominant proportion of the caustic soda used for the saponification reaction for the coagulation bath, which is used at a temperature in the range from 10 to 30 ^° C., is, however, maintained in sodium during this reaction, converted to acetate and, after the isolation of the 4. The method according to any one of claims 1 to 3, 50 saponified copolymers from the solution are so characterized in that the Methanolkonzen- obtained sodium acetate and remaining caustic tration in the methanolic coagulation bath soda in an amount of a few percent in the Solution is 10 to 50 percent by weight. contain saponified copolymers. The sodium acetate 5. Use of the according to one of claims 1 and the caustic soda cause deterioration 4 obtained moldings of the apparent change in the quality of the saponified copolymer, such as Density of about 0.7 to 1.2 in the form of pellets Discoloration, degradation of the polymer and change or chips of microporous structure to make this polymer soluble in the solution of Foils or threads. medium. The discoloration of these copolymers often occurred when the polymers were melt spinning or casting and subjected to heat treatment. In order to prevent this discoloration, it is very desirable to have the separated copolymer immediately wash with water after separation. The invention relates to a method for producing 65 _ The separation or isolation of the saponified of molded bodies from purified saponification products, ethylene-vinyl acetate copolymers from the saponification of Ethylene-vinyl acetate copolymers from the solution is generally after a conventional solution, carried out by known saponification of ethylene ionic processes, for example by