3,376,266? United States Patent Patented Apr. 2, 1968

1 2 is a bivalent radical resulting from the addition of a hy 3,376,266 drogen atom to the nitrogen atom of each of the iso POLYURETHANES PRGDUCED FROM LZ-DIVINYL ETHYLENE GLYCOL cyanate groups of an arylene diisocyanate; ml is an integer Erhard F. Hoegger and James Herbert Werntz, Wilming greater than zero; n is an integer including zero; and the ton, Dei., assignors to E. I. du Pont de Nemours and ~—O-—G-—O—— radicals being 80 to 100 percent of the Company, Wilmington, Del., a corporation of Delaware total of the —O—G—-O— and —O—~B-O— radicals N0 Drawing. Filed Mar. 2, 1964, Ser. No. 348,752 present in said polyurethanes. 5 Claims. (Cl. 260-775) The preparation of these polyurethanes comprises re acting 1,2-divinyl ethylene glycol and a saturated ‘ali 10 phatic glycol with a substantially equimolar amount of ABSTRACT 0F THE DISCLQSURE an arylene diisocyanate, wherein the said 1,2~divinyl Tough, ?lm-forming polyurethanes produced from 1,2 ethylene glycol is 80-100 molar percent of the total gly divinyl ethylene glycol, and optionally a saturated ali col being reacted. However, the preparation may be phatic glycol, and arylene diisocyanates. The process of carried out by any one of several process variations: (a) preparing the above polymers by reacting the monomers glycol(s), alone or in solution, may be added to the di at a temperature between 0° C. and 100° C. for a time isocyanate solution; (b) glycol(s) and diisocyanate can su?icient to obtain a polymer of ?lm-forming molecular be added simultaneously to a solvent; (c) both the weight. glycol(s) and diisocyanate in solution can be added simultaneously; (d) glycol(s) in solution and diisocya 20 This invention relates to new nonelastomeric poly nate not in solution can be added simultaneously; (e) gly urethanes and more particularly to non-elastomeric poly col(s) not in solution and diisocyanate in solution can be urethanes having pendant vinyl groups. added simultaneously; (f) diisocyanate solution may be The preparation of ?lm-forming, essentially linear, added to the glycol(s), alone or in solution; etc. Since it is desirable to protect diisocyanate from atmospheric polyurethanes with pendant vinyl side chains is a very 25 dif?cult task. Where bis-chloroformates and diols are the moisture, it is preferred that the diisocyanate be in solu starting materials, there are problems with the removal of tion. largt amounts of hydrogen chloride. The reaction of di Any of the arylene diisocyanates, i.e., those in which isocyanates and diols often lead to low molecular weight each of the two isccyanate groups is attached directly to an aromatic ring, may be employed. Representative and/or branched polymers because of side reactions. The 30 presence in this invention of vinyl groups to produce arylene nuclei for the diisocyanate are phenylene, naph tough, non-elastomeric ?lms further exaggerates the thylene, biphenylene, anthrylene, ?uorenylene (C13H8) problem of avoiding side reactions since isocyanate groups and benzfurylene. Examples of operable diisocyanates are can react with vinyl groups. For example, it is known that m- and p-phenylene diisocyanate; vinyl isocyanate reacts with itself to give polyamides. 2,4-toluene diisocyanate; ‘ Diisocyanates have been reacted with polymeric glycols dianisidine diisocyanate (4,4'-dimethoXy-3,3’-diisocya having vinyl side groups. However, this only circumvents natobiphenyl) ; the problem by having present very few isocyanate groups 4,4’-biphenylene diisocyanate; with which the vinyl groups could react. Also the polymer 1,5-naphthylene diisocyanate; has very few urethane linkages 40 1,8-naphthylene diisocyanate; bis (4-isocyanatophenyl) methane; bis(4-isocyanatophenyl) ethane; cumene-2,4-diisocyanate; 4-methoXy-1,3-pheny1ene diisocyanate; 4-phenoxy-1,3-phenylene diisocyanate; per total Weight, thus rending it elastomeric and incapable 4-ethoxy-l,3-phenylene diisocyanate; of forming tough ?lms. 2,4’-diisocyanato diphenyl ether; It is therefore an object of this invention to prepare 4,4'-diisocyanato diphenyl ether; tough, stiif ?lm-forming polyurethanes having vinyl side 5,6-dimethyl-l,3~phenylene diisocyanate; chains. It is a further object to prepare ?lm-forming 2,4-dimethyl-1,3-phenylene diisocyanate; polyurethanes having a high percentage of urethane link benzidine diisocyanate (4,4'-diisocyanato biphenyl); ages per total Weight of polymer. It is ‘a still further 4,6-dimethyl-1,3-phenylene diisocyanate; object to provide a method for the preparation of these 1,6_anthracene diisocyanate; polyurethanes. Other objects will appear hereinafter. 2,7-anthracene diisocyanate; These objects have been surprisingly accomplished by 3,3'-dimethyl-4,4'-diisocyanato biphenyl; the polymers of this invention, which are polyurethanes 3,3'-dimethoxy-4,4’-diisocyanato biphenyl; consisting essentially of the recurring structural units 2,5-?uorene diisocyanate; 4,4'-diisocyanato diphenyl methane; and 2,6-diisocyanato benzfurane. The preferred diisocyanate is selected from the group consisting of: wherein -O—G—O— is a bivalent radical obtained by m- and p-phenylene diisocyanate; removing the hydroxyl hydrogen atoms from 1,2-divinyl 2,4-toluene diisocyanate; ethylene glycol; --O-—B—O-- is 'a bivalent radical ob 65 bis(4-isocyanatophenyl)methane; tained by removing the hydroxyl hydrogen atoms from bis (4-isocyanato-phenyl ) ethane; a saturated aliphatic glycol; A is an arylene radical; cumene-2,4-diisocyanate; 4-methoXy-1,3-phenylene diisocyanate; 4-phenoxy-1,3-phenylene diisocyanate; H H0 70 2,4’-diisocyanato diphenyl ether; 4,4'-diisocyanato diphenyl ether; 3,376,266 3 4 5,6-dimethyl-1,3-phenylene diisocyanate; weight) in cyclohexanone of the reprecipitated polymer, 4,4'-diisocyanato diphenyl methane; some properties of which are given below: 2,4-dimethyl-1,B-phenylene diisocyanate; and Inherent viscosity (0.5 % in dimethyl 2,5-?uorene diisocyanate. formamide, 30° C ______0.65. While 1,2-divinyl ethylene glycol provides the essen Thickness (mils) ______0.44. tially linear polyurethane with the pendant vinyl groups, Initial modulus (at 1% elongation) __ 270K p.s.i. up to 20 molar percent of the total glycol may be a satu Elongation at break ______3%. rated monomeric aliphatic glycol, as hereinbefore de Tensile strength ______7.1K p.s.i. scribed, Without substantially affecting the high quality Tear strength ______6.8 g./2” tear/ml. of the ?lm. The preferred saturated monomeric aliphatic 10 X-ray crystallinity ______Amorphorus. glycols are ethylene glycol, propylene glycol and neo Dielectric constant (23° C.): pentyl glycol. Another preferred embodiment of this in At 102 c.p.s ______4.46 vention is to have 1,2-divinyl ethylene glycol as the only At 105 c.p.s ______4.20 glycol present. Dissipation Factor (23 ° C.): In carrying out the preparation of these ?lm-forming 15 At 102 c.p.s ______0.022 polyurethanes, it is desirable to react substantially equi At 105 c.p.s ______0.015 molar proportions of reactants, i.e., equimolar propor~ Soluble in acetone, cyclohexanone, pyridine. tions of hydroxyl groups to isocyanate groups, at a tem Insoluble in ether, petroleum ether, toluene. perature of from about 0 to 100° C. for ‘about \1/2 to 6 Reacts readily with chlorine or bromine vapors with loss hours or until substantially all isocyanate and hydroxyl 20 groups have reacted. Substantially equimolar proportions, of vinyl bands in IR (infra-red). i.e., less than about 5 mole percent excess of either re EXAMPLE II actant, are used to obtain the high molecular weight poly Polymer of fair quality (inherent viscosity 0.3) is ob mers desired and to protect against hydrolysis of any tained by adding, with stirring, equal quantities of a 2.0 free, unreacted isocyanate groups by the moisture in the 25 molar solution of 1,2-divinyl ethylene glycol in absolute air. A temperature range of O-100° C. is desired since pyridine and a 2.0 molar solution of 4,4'-diisocyanato di the reaction rate becomes too slow below 0° C. to 'be phenyl methane in absolute pyridine. The temperature very useful, and above 100° C. undesirable side reactions rises to 54° C. during reaction. The mixture is allowed to become intolerably competitive. The higher the tempera stand for one hour and, from this polymer solution, tough ture the faster the reaction rate. Catalysts, such as di~ 30 ?lms are prepared by casting, drying and washing. butyltin dilaurate, may also be used to aid the reaction. A preferred temperature range from an economic stand EXAMPLE III point is about 50—95° C. Where higher temperatures are Ethylene glycol is substituted for 20 molar percent of used, leading to some side reaction and some low molec the 1,2-divinyl ethylene glycol in the procedure of Ex» ular weight polymers, the polymer may be puri?ed by ample I. Tough ?lms are cast from the resulting polymer. reprecipitation. However, within the desired temperature Likewise, when propylene glycol and neopentyl glycol, range, such reprecipitation is not critical. It is necessary, respectively, are substituted for 20 molar percent of the for high-quality polymers, that the reaction be carried 1,2-divinyl ethylene glycol in Example I, the correspond out under substantially anhydrous conditions to prevent ing tough ?lms are obtained. hydrolysis of the diisocyanate to form urea groups. Common solvents may be used such as tetrachloroethane, EX‘AMPLE IV chlorobenzene, pyridine or mixtures thereof. When each of the ‘following diisocyanates is substi The reaction is always carried far enough to make the tuted in the procedure of Example I in equimolar amounts polymer ?lm-forming, i.e., the number of recurring struc for the diisocyanate used therein, the corresponding tural units is su?icient to give a polymer having an in tough ?lm is obtained in each case: m-phenylene diiso herent viscosity of at least 0.1 and preferably 0.3. In cyanate; p-phenylene diisocyanate; 2,4—toluene diisocy herent viscosity, which is directly related to the mole‘ anate; bis(4-isocyanatophenyl)methane; bis(4-isocya cular weight of the polymer, is de?ned by L. H. Cragg in natophenyl) ethane; cumene-2,4-diisocyanate; 4-meth The Journal of Colloid Science, volume I, pages 261-9 oxy-1,3-phenylene diisocyanate; 4-phenoxy-1,3-phenylene (May 1946) as: Inherent viscosity: (ln relative viscos diisocyanate; 2,4'-diisocyanato diphenyl ether; 4,4,'-di ity)/ C, where relative viscosity is the ratio of the solu isocyanato diphenyl ether; 5,6-dimethyl-1,3-phenylene di tion viscosity to the solvent viscosity, and C is the con isocyanate; 4,4’-diisocyanato diphenyl methane; 2,4-di centration of solute in solution measured as grams of methyl-1,3-phenylene diisocyanate; and 2,5-?uorene di polymer per 100 milliliters of solution. In the subsequent isocyanate. examples, the inherent viscosity is measured and reported Thus is can be seen that the polyurethanes of this in as an 0.5% solution by weight of the polymer at 30° C. vention possess excellent ?lm-forming properties. The . in dimethylformamide solvent. ?lms may be cast from these polyurethanes as in Ex The following examples are merely intended to be il ample I above or by other prior art processes. These stiff, lustrative of the nature of the present invention: tough ?lms are useful for various applications, especial 00 ly for wrapping and tapes. As seen in Example I, the. Ini- r EXAMPLE I tial Modulus (at 1% elongation) is several orders of I A solution of 5 grams (0.02 mole) of 4,4'-diisocyanato magnitude higher than the value ‘for elastomers. diphenyl methane (DDMDI) in 5 milliliters of chloro These advantages have been made possible by the un benzene and 5 milliliters of sym-tetrachloroethane is expected result that the hydroxyl groups of 1,2-divinyl added at room temperature to a solution of 2.24 grams ethylene glycol will react with the isocyanate groups of (0.02 mole) of 1,2-divinyl ethylene glycol (DVG) in 10 arylene diisocyanate without having an intolerable milliliters of sym-tetrachloroethane containing 3 drops of amount of side reaction between the vinyl groups and the dibutyltin dilaurate catalyst. The temperature is raised to isocyan-ate groups. This enables polyurethanes to be’. 95° C. for 1.5 hours under constant stirring. Portions of formed from monomeric glycol, leading to a higher per the viscous polymer solution (inherent viscosity greater centage of urethane linkages than 0.3) are cast directly onto flat surfaces and tough ?lms are obtained on drying. From other portions the It i polymer is precipitated by mixing with petroleum ether (—-N-—G-—-O——) and puri?ed by dissolution and reprecipitation. The best per total weight of polymer than can be produced from ?lms ‘are cast from a 10%—20% solids solution (by polymeric glycols. 3,376,266 5 6 Various changes and modi?cations may be made in this groups from a member selected from the group consist invention Without departing from the spirit or scope ing of m-phenylene diisocyanate; p-phenylene diisocya thereof as de?ned in the following claims. nate; 2,4-‘t0luene diisocyanate; bis(4-isocyanatophenyl) What is claimed is: methane; bis(4-isocyanatophenyl)ethane; cumene-2,4-idi 1. IPolyurethanes having an inherent viscosity of at isocyanate; 4-methoxy-'1,3-phenylene diisocyanate; 4 least 0.1 consisting essentially of the recurring structural phenoXy-1,3-phenylene diisocyanate; 2,4’ - diisocyanato units diphenyl ether; 4,4’-diisocyanato diphenyl ether; 5,6-di 0 H H o 0 H H 0 methylJ1,3-phenylene diisocyanate; 4,4’-diisocyanato di ?Manamallainiwaol l phenyl methane; 2,4-dimethyl-1,3-phenylene diisocyanate; L\ /m \ / n J 10 and 2,5-?uorene diisocyanate. wherein —O—G—-O— is a bivalent radical obtained by 5. The polyurethanes of claim 1 wherein said removing the hydroxyl hydrogen atoms from 1,2-di‘vinyl —-O—1B-—-O— is a bivalent radical obtained by remov ethylene glycol: —O--B—O— is a bivalent radical ob ing the hydroxyl hydrogen atoms from a saturated ali tained by removing ‘the hydroxyl hydrogen atoms from phatic glycol selected from the group consisting of ethyl a saturated aliphatic glycol; A is an arylene radical; m 15 ene glycol, propylene glycol and neopentyl glycol. is an integer greater than zero; n is an integer including Zero; and the —O—G—-O— radicals being 80 to 100 per References Cited cent of the total of the —O—G—O-— and —O‘—-B—O—— UNITED STATES PATENTS radicals present in said polyurethanes. 2,929,800 3/1960 Hill ______260‘——77.5 2. The polyurethanes of claim 1, said —O—G—O— 2,511,544 6/1960 Rinke et a1. ______260-—77.5 radicals being 100 percent of the total of —~O—G—O— 3,100,759 8/’1963 Boussu et a1. ______260‘—77.5 and —O'—B—O— radicals present. 3,219,633 11/1965 Boussu et al. ______260—75 3. The polyurethanes of claim 1 having an inherent viscosity of at least 0.3. DONALD E. CZAJ A, Primary Examiner. 4. The polyurethanes of claim 1 wherein said A is an 25 arylene radical obtained by removing the isocyanate F. MCK‘ELVEY, Assistant Examiner.