Curing Photopolymerizable Compositions Containing N-Substituted Acryloyloxyethyl Amines

The invention is illustrated in the following examples, but is not intended to be limited thereto.

To a 1-liter, four-necked, round bottomed flask fitted with a thermometer and a "Therm-O-Watch", and ice bath atop a pot-lifter, a pressure equalizing addition funnel, a mechanical stirrer and a reflux condenser is added dry diethanolamine (503 g., 1.79 moles). Acrylonitrile (254 g., 4.79 moles) is added dropwise over a one hour period. The temperature of the slightly exothermic reaction is moderated with an ice bath and kept between 40.degree.-45.degree. C. Upon completion of the addition, the reaction temperature is allowed to reach 50.degree. C., and then cooled to ambient temperature (ca. 1.5 hour) to afford 3-[N,N-bis(acryloyloxyethylamino)]propionitrile, a clear, slightly yellow liquid (757 g.), Brookfield Viscosity = 140-150 centipoise (LV No. 2 spindle, 30 rpm). Infrared analysis of the product shows the conjugated CN band (.nu.2240 cm is replaced by unconjugated CN (.nu.2260 cm). Nmr analysis shows the absence of vinyl protons indicating greater than a 95% reaction.

A 2-liter, four-necked, round bottomed flask is fitted with a thermometer, a "Therm-O-Watch", an air ebullator, an oil bath atop a pot-lifter, a 15 plate Oldershaw Column fitted with a variable take-off distillation head, a 500 ml. pressure equalizing addition funnel, and a mechanical stirrer. The flask is charged with 3-[N,N-bis(hydroxyethylamino)]propionitrile (415.0 g., 5.24 eq. of OH), ethyl acrylate (786 g., 7.78 mole, 1.5 eq./eq. of OH), di-n-butyl tin oxide catalyst (6.52 g., 0.026 eq., 0.5 eq. % on OH) and MEHQ inhibitor (1.05 g., 0.1 wt. % on total EA to be charged).

Air ebullition is begun and the reaction mixture is heated to reflux (water, presumably from wet EA, is immediately collected and discarded). As the reaction progresses, ethanol is formed causing the vapor temperature to fall below 80.degree. C.; the reaction mixture becomes homogenous. Distillation is begun at a rate such that the vapor temperature is kept below 80.degree. C. while the volume of the reaction mixture is kept constant by the gradual addition of ethyl acrylate (263 g., 2.63 moles). After 10 hours, glc analysis shows the distillate to contain 213 g. (88.3% conversion of ethanol). At this point, the pot temperature has risen to 115.degree. C. and the vapor temperature to 85.degree. C. (slowing the rate of distillation failed to depress the vapor temperature indicating that ethanol formation has ceased). The distillation head and Oldershaw Column are replaced with a straightlead distillation head. The apparatus is fitted with a steam inlet tube. An additional 0.5 g. of MEHQ is added to the reaction mixture and the excess ethyl acrylate is removed by steam distillation. An azeotrope composed of 85/15//EA/water is collected. Steam distillation is stopped when the EA component of the distillate is no longer discernible (pot temperature 95.degree. C.). The residual water is distilled at reduced pressure (20 mm) at a maximum pot temperature of 100.degree. C. The product, 3-(N,N-bis[acryloyloxyethylamino)]propionitrile (629.2 g., 95% yield, m=1.76, n-0.24) is isolated as a clear, light yellow liquid. EA content = 30-500 ppm, water content = 0.1%, viscosity = 48 centipoise and Br No. = 118.

By substituting for the acrylonitrile of Example 1, Step A, an equimolar quantity of ethyl acrylate and by following substantially the procedure described therein, there is obtained ethyl 3-[N,N-bis(hydroxyethylamino)]propionate. Viscosity = 90 centipoise; hydroxy number = 897 observed/850 theoretical.

By substituting for the 3-[N,N-bis(hydroxyethylamino)]propionitrile of Example 1, Step B, an equimolar quantity of ethyl 3-[N,N-bis(hydroxyethylamino)]propionate and by following substantially the procedure described therein, there is obtained ethyl 3-[N,N-bis(acryloyloxyethylamino)]propionate. Viscosity = 80 centipoise, bromine number = 97.7.

To a 1-liter, four-necked, round bottomed flask fitted with a mechanical stirrer, a thermometer, a "Therm-O-Watch" and a condenser is added diethanolamine (472.5 g., 4.5 moles) and acrylamide (319.5 grams, 4.5 moles). The mixture is heated to 60.degree. C. whereupon the contents become homogenous. At this point, a moderate exothermic reaction occurs which raises the reaction temperature to 100.degree. C. The product, 3-[N,N-bis(hydroxyethylamino)]propionamide, is cooled and used in the following step without further purification.

By substituting for the 3-[N,N-bis(hydroxyethylamino)]propionitrile of Example 1, Step B, an equimolar quantity of 3-[N,N-bis(hydroxyethylamino)]propionamide and by following substantially the procedure described therein, there is obtained 3-[N,N-bis(acryloyloxyethylamino)]propionamide.

By substituting for the acrylonitrile of Example 1, Step A, an equimolar quantity of methylvinylketone and by following substantially the procedure described therein, there is obtained 4-[N,N-bis(hydroxyethylamino)]butan-2-one.

By substituting for the 3-[N,N-bis(hydroxyethylamino)]propionitrile of Example 1, Step B, an equimolar quantity of 4-[N,N-bis(hydroxyethylamino)]butan-2-one and by following substantially the procedure described therein, there is obtained 4-[N,N-bis(acryloyloxyethylamino)]butan-2-one.

The following table, taken together with the equations, illustrates the various starting materials, intermediate and final products which can be prepared and employed as accelerators with other photopolymerizable monomers or employed themselves as photopolymerizable monomers. ##STR6##

To a 1-liter, four-necked, round bottomed flask equipped with a thermometer, "Therm-O-Watch", air ebullator, oil bath atop a pot lifter, a fifteen plate Oldershaw column fitted with a variable take-off distillation head, 500 ml. pressure-equalizing addition funnel and a mechanical stirrer is added dry triethanolamine (50 g., 0.336 mole), dry ethyl acrylate (300 g., 3 moles), hydroquinone monomethyl ether (MEHQ) (0.38 g., 0.13 wt. % on monomer) and dibutyl tin oxide catalyst (1.92 g., 0.008 mole). The reaction mixture is heated to reflux while gentle air ebullition is maintained. As the reaction proceeds, the vapor temperature falls below 80.degree. C.; distillation is begun and maintained at a rate such that the vapor temperature is kept below 80.degree. C. The pot volume is kept approximately constant by the addition of fresh ethyl acrylate. The ethanol content of the distillate is measured by glc analysis. After 11 hours, the total ethanol distilled reaches 0.67 mole (m = 2.0) and the reaction is terminated. The Oldershaw column and distillation head are replaced with a straight-lead distillation head and the excess ethyl acrylate removed under vacuum during which air ebullition is maintained to prevent polymerization. The maximum pot temperature is 100.degree. C. The product is isolated as a clear, liquid, viscosity, 55 centipoise.

Nmr analysis shows the reaction conversion to be 66% (m = 2.0, n = 0.0).

The following Table II taken together with the following equation illustrates the various starting materials and final products which may be prepared by following substantially the procedure in Example 17: ##STR8##

The compounds of Examples 17-22 are all liquids of low viscosity. The values for m and n are obtained from nuclear magnetic resonance spectra by the relative areas (integrated) of the proton absorption centered at .delta.4.3 ppm ##STR11## versus the proton absorption centered at .delta.3.6 ppm (CH.sub.2 OH). The percent conversion is calculated as follows: ##EQU1##

The products are further characterized by infrared spectroscopy and show characteristic absorptions at .nu.1740 cm.sup.-1 (carbonyl, ester), 1650 cm.sup.-1 (doublet, C.dbd.C) and