DE1186618B - Process for producing highly elastic molded articles based on polyurethane - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY Internat. KL: CO & g

GERMAN

PATENT OFFICE

EDITORIAL

German class: 39 b - 22/04

Number: 1186 618

File number: B 73043IV c / 39 b

Filing date: August 8, 1963

Opening day: February 4, 1965

It is known by reaction of isocyanate-modified To produce polyhydroxyl compounds with diols or diamines in solution polymers, which can be processed into elastic films or fibers with good performance properties. However, since diamines react extremely quickly with isocyanates, undesired swelling often occurs of the polymer solution.

"It is also known in the manufacture of such Use polymers instead of diamines, the less reactive dihydrazides. However, connections produced in this way have the disadvantage that they tend to stick together.

Finally, it is known to produce crosslinked plastics containing urethane and urea groups, by using reaction products containing at least two isocyanate groups from polyisocyanates and organic compounds with at least one reactive hydrogen atom, optionally in solution, initially reacted with monofunctional alkylenimines and these low molecular weight Intermediate products cross-linked in a further stage. Plastics produced in this way cannot be processed into moldings without decomposition.

It has now been found that highly elastic molded bodies based on polyurethane can be reacted of substantially linear isocyanate-modified polyhydroxyl compounds with molecular weights from about 750 to 6000 terminal isocyanate groups with bifunctional nitrogen compounds in solution and subsequent shaping with removal of the solvent can by using substances of the general formula as bifunctional nitrogen compounds

Method of manufacture

highly elastic molded body based on polyurethane

Rr

R ₂

R ₂

: n — ν

in which Ri and R _{2 are} hydrogen atoms, alkyl, ζ. Β. Methyl, ethyl or propyl radicals, or aryl radicals, such as a phenyl radical, Ra zero or an alkylene radical having 1 to 10 carbon atoms, which can optionally be interrupted and / or substituted by heteroatoms, are used.

With this method, the disadvantages outlined at the outset occur to a much lesser extent on.

Applicant:

Aniline & Soda Factory in Baden

Corporation,

Ludwigshafen / Rhine

Named as inventor:

Dr. Joachim Kunde, Frankenthal (Palatinate);

Dr. Robert Gehm, Ludwigshafen / Rhine

The reaction of the isocyanate-modified polyhydroxyl compounds with the substances used according to the invention, which are known as diamidrazones, leads to largely linear products that are soluble in strongly polar organic solvents. This is surprising since it is known that both imino groups, e.g. B. those in imino ethers, as well as hydrazine derivatives, such as dicarboxylic acid hydrazides, can react with isocyanates and such reactions become crosslinked and insoluble Products would have to lead, which can then no longer be processed from the solution.

Suitable polyhydroxyl compounds which are reacted in a known manner with diisocyanates to form isocyanate-modified polyhydroxyl compounds are, for example, known polyethers, polythioethers, polyesters or polyacetals with terminal hydroxyl groups and molecular weights such that the isocyanate-modified polyhydroxyl compounds have molecular weights of about 750 to 6000 and a melting point below 50 ⁰ C have.

Such hydroxyl-containing polyethers or polythioethers are, for example, the polymers Ethylene oxide, propylene oxide or tetrahydrofuran, their copolymers or addition products to polyols, such as glycol or butanediol, and the polymers made from thiodiglycols. Suitable polyester can for example be made from for it

509 507/374

customary dicarboxylic acids, such as adipic acid, azelaic acid, sebacic acid or decanedicarboxylic acid, and diols, such as ethylene glycol or 1,2-propylene glycol, or other branched or unbranched diols, the ratio of branched or unbranched starting materials being advantageously chosen so that the polyester formed has a melting point below 5O ⁰ C possesses. Suitable polyacetals are made, for example, from polyhydric alcohols and aliphatic aldehydes, e.g. B. from formaldehyde or p-formaldehyde and hexanediol, methylhexanediol, heptanediol or octanediol, or are cyclic acetals, such as butanediol formal. The polyhydroxy compounds mentioned can be obtained by known processes. Their production is not the subject of this invention.

For the production of the isocyanate-modified polyhydroxy compounds The polyethers, polythioethers, polyesters or polyacetals can either be used alone or mixed with diisocyanates in a known manner. Polyhydroxyl compounds with smaller molecular weights, e.g. B. with a molecular weight of about 1000, can initially converted into higher molecular weight polyhydroxyl compounds with a deficit of diisocyanate which have then been modified with further diisocyanate.

The known reaction of polyhydroxyl compounds with diisocyanates is expediently carried out in a molar ratio of 1: 2 at temperatures between 80 and 120 ^° C. within 1 to 2 hours.

For special products with changed elasticity, however, there are also deviations from this molar ratio up and down possible. The polyhydroxyl compounds can with diisocyanates both in the absence and in the presence of inert solvents such as methylene chloride or Benzene. However, it is advisable to use isocyanate-modified Polyhydroxyl compounds prepared in the presence of non-polar inert solvents, the Remove solvent.

Particularly suitable polyisocyanates are aromatic diisocyanates such as 1,4-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate or tolylene diisocyanate. But there are also aliphatic diisocyanates, such as hexamethylene diisocyanate, or such Diisocyanates, by partial or total hydrogenation of the above aromatic Diisocyanates can be prepared, suitable.

Suitable diamidrazones are the known reaction products of aliphatic diimino ethers or dinitriles with hydrazine or its substitution products, for example adipic acid diamidrazone, Sebacic acid diamidrazone or especially oxaldiamidrazone, which is known to consist of 1 mole of oxaliminomethyl ether and 2 moles of hydrazine hydrate can be prepared by mixing the components in an inert solvent such as dioxane.

The reaction of the isocyanate-modified polyhydroxyl compounds with the diamidrazones is expediently in inert polar solvents such as dimethylformamide, dimethylacetamide or tetramethylene sulfone, carried out. These solvents can also be mixed with other, less polar solvents, such as tetrahydrofuran or Dioxane can be used.

The inventive method can be advantageously carried out so that they are heated up to about lOgewichtsprozentige solutions Diamidrazonen which advantageously to temperatures between 30 and 8O ⁰ C, in vigorously stirred, for instance between 10 and 30gewichtsprozentige solutions of isocyanate-modified polyhydroxyl compounds which advantageously about Have normal temperature, enters. Of course, the solution of diamidrazones can also be initially taken and the solution of the isocyanate-modified polyhydroxyl compounds added. The solutions of isocyanate-modified polyhydroxyl compounds and the solutions of diamidrazones can be mixed by means of known mixing devices, e.g. B. nozzles are mixed. Depending on the solids content after the solutions have been combined, low to high viscosity solutions are formed immediately after mixing the solutions, which are practically colorless and stable. Known additives, such as fillers, pigments, dyes or stabilizers, can be added to the solutions before shaping. Moldings are now produced from the solutions in a known manner. Films are produced, for example, by applying the solutions to plates or suitable endless belts and removing the solvent. Threads are z. B. obtained by spinning the solutions by means of nozzles according to the known dry or wet spinning process. The threads are highly elastic and are particularly suitable as textile materials.

Highly elastic coatings can be made, for example, by dipping moldings into the Solutions containing polymers and removing the solvent after removing the coated ones Shaped bodies are produced.

The parts and percentages given in the example are based on weight.

example

165 parts of a mixed polyether diol (molecular weight 1650), prepared in a known manner from about 2 parts of tetrahydrofuran and about 1 part of propylene oxide, are ^{stirred with 48.8 parts of 4,4'-diphenylmethane diisocyanate for 2 hours at 100 °} C. with the exclusion of moisture, the reaction vessel with Nitrogen is purged. After the mixture has cooled, 214 parts of dimethylformamide are added. The solution has an isocyanate content of 1.63%. Thereafter, a heated to about 6O ⁰ C solution of 10.2 parts Oxalamidrazon is added in 1810 parts of dimethylformamide, while stirring vigorously. Pouring the polymer solution in a 3 mm layer onto a glass plate and evaporating the solvent gives a highly elastic, non-adhesive film.

Claims (2)

Claim: Process for producing highly elastic molded bodies based on polyurethane by reacting substantially linear isocyanate-modified polyhydroxyl compounds with molecular weights from about 750 to 6000 and terminal isocyanate groups with bifunctional nitrogen compounds in solution and subsequent shaping with removal of the solvent, characterized in that one 5 6 as bifunctional nitrogen compounds substances in which Ri and R2 are hydrogen atoms, alkyl or of the general formula aryl radicals, R3 zero or an alkylene radical, the optionally interrupted by heteroatoms R. 2 R2 and / or can be substituted, mean, Ri \ I I / Ri 5 turns. / N-Nv / N-N ^ W ^ C - R ₃ - C Ή Considered publications: Yi-W ^ NH German Auslegeschrift No. 1 112 286. 509 507/374 1.65 © Bundesdruckerei Berlin