DE1160615B - Process for the production of high molecular weight polymers of formaldehyde - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 08 g

German class: 39 c-18

Number: 1 160 615

File number: S 72739IV d / 39 c

Filing date: February 27, 1961

Opened on: January 2, 1964

It is known to formaldehyde polymers with various properties by polymerizing the to produce monomeric formaldehyde. Teach publications by Staudinger or Walker, that purified anhydrous formaldehyde must be cooled to - 80 ° C until it condenses, whereupon the condensate takes about five or more days to form a polymer, its amount is very small, to be generated by polymerization in solution or in the mass itself. to

Some patents describe the introduction of purified anhydrous formaldehyde gas into one inert solvent, the polymerization catalysts, ζ. B. contains an amine, arsine or phosphine, to obtain high molecular weight polyformaldehyde. Albeit through this A process of polymeric formaldehyde with almost satisfactory properties has been obtained, so these processes bring with them some difficulties, the catalysts from the polymer Remove product. There are many publications that address the disadvantages of the remaining catalyst describe in relation to the stability of the polymer.

This is similar to the fact that the removal of polymerization catalysts from organometallic compounds or pieces of the same made of so-called high density polyethylene is very difficult, the retained catalyst adversely affecting the stability of the polyethylene. One catalytic polymerization therefore has an unavoidable disadvantage, so that finding a Procedure in which no compound can easily have undesirable effects on the stability of the End product can exercise, used as a catalyst, is desired.

On the other hand, it was recognized that a higher degree of polymerization was necessary by as much as possible an effect of the terminal groups which is believed to reduce the resistance of the final polymer affect to downsize, resulting in a greater rate of polymerization and, accordingly the use of a polymerization catalyst is required.

It has now been found that polymers of formaldehyde can be obtained by irradiating essentially anhydrous monomeric formaldehyde with ionizing rays at temperatures from - 80 to + 100 ° C, if necessary in the presence of inert solvents and stabilizers, by carrying out the polymerization by means of ultraviolet rays.

Process for the preparation of polymers of formaldehyde with a high molecular weight

Applicant:

Sumitomo Chemical Company, Ltd., Osaka,
Japanese Association for Radiation Research
on Polymers, Tokyo (Japan)

Representative:

Dr.-Ing. H. Ruschke, patent attorney,

Berlin 33, Auguste-Viktoria-Str. 65

Named as inventor:

Seizo Okamura, Kyoto,

Seizo Nakashio, Nishinomiya-shi,

Kaichiro Bayashi, Osaka (Japan)

Claimed priority:

Japan February 26, 1960 (No. 5862)

This is based on the knowledge that the polymerization by irradiation with ultraviolet Radiation is greatly accelerated. This ultraviolet radiation is cheaper and safer than radiation with ionizable gamma rays, and the apparatus required for this is simpler.

The irradiation can be carried out in the presence or absence of inert solvents. The presence a solvent is preferable for ease of control of the process conditions and the aftertreatment and removal of the polymeric product, for example the polymerization temperature or the rate of polymerization. The polymerization can therefore take place in the presence run by solvents at a temperature which differs from the boiling point of the Solvent (about 100 ° C) extends up to a temperature that by usual freezer mixes (approx. - 80 ° C) is generated.

You can the polymerization in general at about -20 ° C in the dissolved state or at a Carry out temperature above - 20 ° C and under pressure in the mass itself.

The solvents are inert to formaldehyde, resistant to ultraviolet rays and at the polymerization temperature liquid. You choose them

309 777/414

3 4

from chain-like or cyclic saturated ali- is passed for pre-dehydration and cleaning, phatic hydrocarbons, aromatic hydrocarbons, the formaldehyde gas was in a on about lenwasserstoffen without unsaturated side groups, - 80 ^; C with solid carbon dioxide — methanol, from halides of these hydrocarbons, condensed from a cooled separator, whereby 30 parts of saturated aliphatic ethers (chain-like or 5 monomeric formaldehyde were obtained. The so cyclic) and from saturated aliphatic ketones. The monomeric formaldehyde obtained was in Hart all through one can pentane, hexane, benzene, methyl glass ampoules of 19 mm (outer diameter) and lene chloride, ethylene dichloride, diethyl ether, tetra about 1 mm thick, which 2.0 parts of purified hydrofuran, dioxane and Use acetone. These acetone were added, by default, a solvent must be essentially anhydrous when filled with an acetone at 5 mm Hg pressure. solution was obtained, the 4.1 parts of the monomer

The process can be carried out technically, included. The ampoules were blown with a mercury by blowing purified formaldehyde gas into the solution silver lamp (HL-400-P type, manufactured by Tokyo Middle and at the same time continuously ultraviolet Shibaura Elec. Co., Ltd.) from a distance of rays at a certain temperature act i ₅ 30 cm ^{irradiated at -80 °} C for 2 hours. This means that the polymer obtained can be recovered using methanol and acetone. On the other hand, you can also wash the thoroughly and under reduced pressure irradiation on a solution of cleaned mold - dried at 50 ° C for about 50 hours, leaving the aldehyde to act. 1.9 parts of solid formaldehyde polymer were obtained

Monomeric formaldehyde is preferred in the 20th century. Mp. 173 to 176 "C; intrinsic viscosity essentially anhydrous and contains, for example (intrinsic viscosity): 1.56. (The viscosity was less than 2%, even better less than 1% at 60 ^; C in a 0.5" / The monomeric formaldehyde can be obtained from polymerizate in p-chlorophenols which give 2% a-pinene, which is measured at certain levels the intrinsic viscosity is determined in the same way.) homely paraformaldehyde and a-polyoxymethylene. "~ .

be used. One of the conditions of the example _

driving is that an impurity of 5.0 parts of monomeric formaldehyde, as in

polymeric product is prevented. Meanwhile, Example 1 can be obtained. were made by Destilman during the polymerization, catalytic compound in ampoules of the same type as in Example 1 Use genes that have a beneficial effect on the filled and then use a mercury lamp (GT resistance of the final polymer, e.g. 1511 type) from a distance of 20 cm Benzophenones, deoxybenzoins, benzoins, aceto -80 ° C irradiated for 18 hours. 1.2 were obtained phenones, benzyls, benzoresorcines, fluolecithins, parts of polymer. Benzoyl peroxides and acyloins. These connections 35 Example 1

are both well-known accelerators of the ultraviolet ^p

irradiation as well as light stabilizers for polymer As in Example 1 obtained monomeric formal

sate. They can be in an amount from 10 to 0.001 dehyd was a weight percent by distillation in ampoules, preferably 1 to 0.01 ⁰ Zo of the re- filled, containing the prepurified methylene chloride, action solvent or monomeric formaldehyde 40 followed whereupon the procedure of Example 1 use hyds. The addition of the catalyst, itself, to make a methylene chloride solution, in a very small amount, accelerates the poly- which contained 4.4 parts of the monomer, merization and favors the formation of higher poly-.

merisate. The monomeric formaldehyde can be obtained from a mercury lamp (HL-400-P type) if desired by ultraviolet rays or 45 at a distance of 30 cm for 3 hours irradiated by low dose gamma rays from -80 ° C, resulting in 0.2 parts of polymer be pre-cleaned in a cone. were obtained. Intrinsic viscosity: 1.06.

For this purpose, formaldehyde gas can be irradiated. .

passes through a separator, which at 0 Example 4

to ^{-40 0} C is kept in order to bring about a prepolymer 50 monomeric formaldehyde, which was obtained as in Example 1 with simultaneous removal of the impurities, was produced by distillation at 6 mm, whereupon the prepurified gas Hg pressure after Procedure of Example 1 is fed to a polymerization zone. treated. 2.0 parts of acetone were added to the ampoules.

The polymerization, like other polymers, has been set before the monomer is filled in, inhibited by oxygen, which is why the ab- 55 was. There was obtained an acetone solution which is 6.4 purities of oxygen desired. Particularly contained in parts of monomeric formaldehyde. After the case, when the reaction rate were very closed in ampoules, they were slow with a slow, oxygen exerts an undesirable effect on the mercury polymerization lamp (HL-400-P type) from a discharge, which with the distance of 30 cm at ^-80: C 2 ¹ / · hours when stability of the polymeric product in relation 60 radiates. The polymer produced in this way was with stands. The following examples illustrate the pre-acetone and methanol washed and subject invention. All parts given are dry under pressure at 50 ^: C for about 50 hours, parts by weight, unless otherwise stated. whereby a white, powdery polymer is obtained

_B. ■] 1 became. Intrinsic viscosity: 0.74.

50 parts of paraformaldehyde are used in nitrogen ° Example 5

stream heated to 160 to 180 ° C and by four ab- 0.009 parts of benzoin were in 5.0 parts

separator, the temperature at - 30 ⁰ C dissolved held reinigtem acetone. 2.0 parts of the solution was

those placed in ampoules according to the procedure of Example 1. Formaldehyde was then prepared as in Example 1, filled into the ampoules by distillation under 6 mm Hg pressure, whereby an acetone solution containing 5.8 parts of the monomer was prepared. The ampoules were observed with a mercury lamp (HL-400-P type) from a distance of 30 cm

- Irradiated 80 ° C for 30 minutes, whereby 3.1 parts of a high molecular weight polymer were obtained. Intrinsic viscosity: 1.4.

Example 6

As in Example 1, 2.0 parts of methylene chloride were added to the ampoules. It then became more monomeric Formaldehyde, as prepared in Example 1, into the ampoules by distillation under 5 mm Hg pressure was charged, whereby a methylene chloride solution containing 5.8 parts of the monomer was obtained. The ampoules were treated with a mercury lamp ao (HL-400-P type) from a distance of 30 cm

Irradiated 40 ° C for 1 ¹ ^ hours, as a result of which 2.7 parts of polymer were produced. Intrinsic viscosity: 0.95.

Example 7

0.050 part of benzophenone was dissolved in 10 parts of purified acetone. From this solution were 3.0 parts are added to ampoules as in Example 1, whereupon monomeric formaldehyde is then produced in these as in Example 1, was introduced by distillation under 5 mm pressure, whereby a solution, containing 4.3 parts of formaldehyde was obtained. The vials were filled with a mercury lamp (HL-400-P type) irradiated from a distance of 30 cm at -80 ° C for 30 minutes. The one made in this way Polymer was washed with methanol and acetone and under reduced pressure at 50 ° C dried for about 50 hours, 2.2 parts of solid polymer having been produced. Internal viscosity: 1.7.

Claims (1)

Claim: Process for the preparation of polymers of formaldehyde by irradiating essentially anhydrous monomer! Formaldehyde with ionizing radiation at temperatures from -80 to +100 ⁰ C, optionally in the presence of inert solvents and stabilizers, characterized in that one carries out the polymerization by means of ultraviolet rays. Considered publications:
French patent specification No. 1130 099,
1130100;
U.S. Patent No. 2,768,994. 309 777/414 12.63 © Bundesdruckerei Berlin