DE1104697B - Process for the production of rubber-like plastics containing urethane groups - Google Patents

Description

The production of polymers with rubber-like properties by reacting a polymer A relatively low molecular weight compound with a diisocyanate is known. Even is from the German patent 908 197 the production of orientable threads spinnable and thus non-rubbery threads by chain extension of a preformed polyester, polyamide or the like known with a diisocyanate. A proposed diisocyanate for this purpose is toluene-2,4-diisocyanate.

The invention now provides a process for the production of rubber-like polymers, which opposite the known rubber-like polymers have the advantage of improved light stability. the Polymers obtained according to the invention are characterized by the fact that their diisocyanate components are aromatic and have a lower alkyl group on each core carbon atom adjacent to an isocyanate group sits.

These polymers are made into an active by reacting a diisocyanate defined above Hydrogen-atom-bearing, difunctional polymers with a molecular weight between 700 and 8000 and with a melting point below 60 ° C with the formation of terminal NCO groups polymeric product and subsequent reaction of this product with a low molecular weight, difunctional, two active hydrogen atoms-bearing compound in at least an equivalent ratio of active hydrogen atoms obtained to the NCO groups. In a particularly advantageous embodiment according to the invention, as the compound containing active hydrogen atoms, such a compound is used in a conventional reaction with the diisocyanate used alone a polymer with would give a melting point above 200 ° C, provided that the molecular weight of this polymer lies in the fiber-forming area. In this case, the end product consists of what are called "soft segments" originating from the polymeric starting material and from the low molecular weight, active hydrogen atoms carrying reactants and the diisocyanate derived »hard Segments «.

If the products obtained according to the invention are to be used for the production of threads, so they expediently contain the hard and soft segments defined above. The molecular weight fraction the soft segments and thus also that of the polymeric starting material should be around 800 to 3500.

Examples of suitable polymeric starting materials are poly processes containing terminal OH groups for the production

of rubbery,

Having urethane groups

Plastics

Applicant:

EI du Pont de Nemours and Company,
Wilmington, Del. (V. St. A.)

Representative: Dipl.-Ing. E. Prince

and Dr. rer. nat. G. Hauser, patent attorneys,

Munich-Pasing, Bodenseestr. 3 a

Claimed priority:
V. St. v. America March 29, 1956

August Henry Frazer, Wilmington, Del.,
Joseph Clois Shivers, West Chester, Pa.,
and John Joseph Verbanc, Wilmington, Del. (V. St. A.) have been named as inventors

alkylene glycol ethers, polyureas, each on the amino nitrogen atom the recurring urea grouping having a basic amino H atom bonded Polymers (polyureylenes), polyurethanes, polyamides, polysulfonamides and polyesters, as well as mixed Polymers made from two or more of the compounds mentioned. A small number of urethane bonds polyalkylene glycol ethers comprising are preferred.

4.0 The lower alkyl substituent in the aromatic Diisocyanate is preferably a methyl or isopropyl group, and the preferred diisocyanates are 2,4,6-tri-lower alkyl-1,3-phenylene diisocyanate. Surprisingly, it has been found that these triply substituted 1,3-phenylene diisocyanates obtained polymers much more soluble, e.g. B. in dimethylformamide, are substituted as those of four times Corresponding polymers obtained from phenylene diisocyanates. This is important when polishing to be spun into threads according to the dry spinning process.

The difunctional, low molecular weight compound used can be hydrazine or an aromatic one Diamine, e.g. B. Ethylenediamine bis-p-aminophenyl-

109 540/439

methane, bis-4-aminocyclohexylmethane or 2,5-dimethyl-piperazine, be.

Polymers intended for the manufacture of threads preferably have a melting point above 150 ° C. It has been found that from the polymers obtained as described above without Hardening or cross-linking of threads with a resilience of more than 90% and a loss of strength can produce less than 20%.

10

Example I.

3 mol drier, terminal O Η groups Poly-n-butylene glycol ether with an average molecular weight of about 1000 are mixed with 2 moles of 2,4-tolylene diisocyanate by heating for 3 hours reacted on the steam bath under nitrogen. A low molecular weight polymer is obtained in this way with terminal hydroxyl groups and an average of 3 poly-n-butylene glycol ether esters per molecule.

48.4 g of this "trimer" are mixed with 6.1 g of 2,4,6-trimethyl-1,3-phenylene diisocyanate under nitrogen 30 ecm of xylene reacted for 2 hours at 125 to 130 ° C. A trimer is obtained in this way with terminal isocyanate groups. The solvent is separated off under reduced pressure. The residue is dissolved in 150 ecm Ν, Ν-dimethylacetamide solved. A solution of 0.75 g of hydrazine hydrate in 15 ecm is added to this solution at 0 ° C Dimethylacetamide. After 10 minutes the highly viscous solution containing 25% solids becomes at 40 ° C spun into threads in the usual way using the dry spinning technique. The freshly spun threads are made from an elastomer and have a strength of 0.51 g per denier, a twist of 870%, an initial modulus of 0.05 grams per denier, a resilience to tensile strength of 98% and a loss of strength of 5.7%.

After boiling for 30 minutes in a 0.5% sodium lauryl sulfate containing aqueous solution and subsequent rinsing with distilled water Thread samples containing 30 individual threads in a thread-0-meter of exposure to ultraviolet Exposed to light. This exposure took place with a carbon arc enclosed in Pyrex glass, whose light consists of 14% ultraviolet light with 3000 to 4300 Å. The samples were in a distance of 203.2 mm from the light source. After 14 hours of exposure, the sample was still there not noticeably discolored. A similarly prepared thread in which diphenylmethane-4,4'-diisocyanate is used End group formation of the trimeric polyglycol ether urethane was also used in the Fade-0-meter exposed. With this thread, a pronounced one occurred after 4 hours of exposure Yellowing, which increased with continued exposure.

Films cast from dimethylacetamide solutions of the above polymers show that the invention obtained polymers have a much better light stability than the control polymers.

Example II

Dry poly-n-butylene glycol ether with an average molecular weight of about 1000 is reacted with 2,4-tolylene diisocyanate in a molar ratio of 2: 1. This gives a low molecular weight polymer with terminal hydroxyl groups and an average of two polyether groups per molecule. 10.6 g of this "dimer" are reacted with 2.0 g of 2,4,6-trimethyl-1 ₎ 3-phenylene diisocyanate in 20 ecm of xylene for 2Va hours at 125 to 130 ° C under a nitrogen atmosphere, with the polyglycol ether urethane contains terminal isocyanate groups. The xylene is then separated off under reduced pressure. The viscous dimer is dissolved in 110 ecm dimethylacetamide. A solution of 0.25 g of hydrazine hydrate in 5 ecm of dimethylacetamide is added to the cooled solution of the dimer with terminal isocyanate groups. The solvent is removed under reduced pressure to a solids content of the solution of approximately 25%. Films cast from this solution are translucent and tough. When exposed in the fade-0-meter, as in the previous example, the film shows no discoloration even after 39 hours. A similarly produced film, in which diphenylmethane-4,4'-diisocyanate is used for the formation of end groups, shows a yellow coloration after 4 hours of exposure in the fade-0-meter.

In addition to the aforementioned dimethylacetamide, the polymers are also in dimethylformamide soluble.

Example III

5.45 g of the "dimer" identified in Example II, 1.01 g of 2,4,6-trimethyl-1,3-phenylene diisocyanate and 20 ecm of xylene are placed in a three-necked flask equipped with a nitrogen supply and a stirrer. The mass is heated to a temperature between 125 and 130 ° C for 2 hours while stirring. Then xylene is distilled off under reduced pressure. The dimer with terminal isocyanate groups formed in this way is redissolved in 32.5 ecm of dimethylformamide at room temperature. After cooling the solution to 3 to 5 ° C, 0.15 g of ethylenediamine in 5 ecm of dimethylformamide is added. A polymeric product is deposited in the process. This is brought back into solution by adding 20 ecm of dimethylformamide. A film is cast from the solution. This is boiled in water containing 0.5% sodium lauryl sulfate. The film is hydrophobic and shows no discoloration after 24 hours of exposure to ultraviolet light in the fade-0-meter.
As a control, 0.870 g of 2,4-tolylene diisocyanate are used in place of the diisocyanate used above. The example is otherwise repeated. The film obtained is brown after only 20 hours of exposure in the fade-0-meter.

Example IV

0.525 g of bis (4-aminocyclohexyl) methane are used in place of the ethylenediamine to produce the polymers from Example III used. The one made with 2,4,6-trimethyl-1,3-phenylene diisocyanate Polymer obtained film showed after 24 hours of exposure to ultraviolet light in the fade-0-meter no discoloration. The one obtained from the control polymer made with 2,4-tolylene diisocyanate The film is strongly discolored after just 20 hours of exposure.

Example V

Instead of the ethylene diamine used to prepare the polymers from Example III 0.285 g of dimethylpiperazine used. The exposure tests match those obtained in Example IV identical results.

Example VI

32.1 g of the "trimer" from Example I are mixed with 5.72 g of 2,4,6-triisopropyl-1,3-phenylene diisocyanate under nitrogen Brought to reaction at 110 ° C. for 2 hours. The polymer obtained with terminal Isocyanate groups are dissolved in 100 g of dimethylformamide at 50 to 70 ° C. The solution of the polymer is slowly added to 0.4 g of hydrazine hydrate in 30 g of dimethylformamide with vigorous stirring until a viscous solution is obtained. The solution is then concentrated to about 35% solids. The high solubility observed is surprising. Then the polymer goes to the usual Way spun into threads at around 90 ° C using the dry spinning process. These consist of Elastomers and have a tenacity of 0.51 grams per denier, an elongation of 840%, an initial Modulus of 0.03 grams per denier, a springback under tension of 99% and a loss of strength of 3.7%. With exposure in the fade-0-meter as in example I, the thread shows no discoloration after 21 hours.

Example VII _{$ 2}

20 g of the "dimer" from Example II and 5.72 g of 2,4,6-triisopropyl-1,3-phenylene diisocyanate are used Reacted with one another for 4 hours at 110 ° C. under nitrogen. The polymer will be like in that previous example dissolved in 50 g of dimethylformamide and slowly with stirring to 0.4 g of hydrazine hydrate added in 100 g of dimethylformamide. The solution obtained is not viscous. After adding about 0.05 g of hydrazine hydrate improves the viscosity. A film cast from such a solution is tough and elastic and soluble in chloroform-methanol (20: 1). It was observed that with 2,4,6-triisopropyl-1,3-phenylene diisocyanate obtained polymers swelled by methanol in contrast to similar polymers from 2,4,6-trimethyl-1,3-phenylene diisocyanate will.

Example VIII

5.45 g of the "dinning" obtained in Example II, 1.53 g of 4,4'-methylene-bis (2,6-dimethylphenylene) diisocyanate and 20 ecm of xylene are placed in a three-necked flask equipped with a nitrogen supply and a stirrer appropriate. The mass is then heated on the steam bath with stirring for 24 hours. Man xylene is then distilled off under reduced pressure. The isocyanate-terminated dimer formed in this way is redissolved in 23 ecm dimethylacetamide at room temperature. After the Solution at 2 to 5 ° C, a solution of 0.125 g of hydrazine hydrate in 5 ecm of dimethylacetamide is added. From this solution a film is poured after 20 minutes, which in 0.5% sodium lauryl sulfate containing water is boiled. After 24 hours of exposure to ultraviolet light in the Fade-O-meter, this film shows no discoloration.

A film prepared in the same way from diphenylmethane-4,4'-diisocyanate shows after exposure for 10 hours a pronounced yellowing in the fade-0-meter.

Claims (5)

PATENT CLAIMS: 1. Process for the production of rubber-like plastics containing urethane groups by reaction of the reaction products of polyfunctional polymers and at least the equivalent amount of aromatic diisocyanate with low molecular weight polyfunctional compounds, characterized in that the reaction products containing the NCO groups aromatic diisocyanate with lower alkyl groups at those core carbon atoms which carbon atoms carrying isocyanate groups are adjacent, and a difunctional polymer bearing active hydrogen atoms a molecular weight between 700 and 8000 and a melting point below 60 ° C with a low molecular weight, bifunctional, active hydrogen atom-bearing compound in at least equivalent ratio of active hydrogen atoms to the NCO groups. 2. The method according to claim 1, characterized in that a low molecular weight, difunctional Compound is used, which in the usual reaction with about the equivalent Amount of the same aromatic diisocyanate a polymer with a melting point above 200 ° C in the fiber-forming molecular weight range. 3. The method according to claim 1 and 2, characterized in that one is called difunctional, active Compound containing hydrogen atoms uses a diamine. 4. The method according to claim 1 and 2, characterized in that as a difunctional, active Hydrogen atom-containing compound hydrazine is used. 5. The method according to claim 1 to 4, characterized in that there is a reaction product such from a polyalkylene glycol ether containing OH groups with 2,4,6-trimethyl-1,3-phenylene diisocyanate or 2,4,6-triisopropyl-1,3-phenylene diisocyanate is used. Considered publications:
German patent specifications No. 831 772, 838 826,
652, 908 197, 933 783. © 109 540/439 4.