Hydroxy alkyl (amino) acrylate monomers and copolymers thereof

The process for preparing novel compounds having the formula ##STR1## by the reaction of a bicyclic amide acetal of formula ##STR2## and an olefinically unsaturated carboxylic acid of formula ##STR3## wherein R, R', R" and R"' independently represent hydrogen, an alkyl group or an alkyl ether group having from 1 to 20 carbon atoms, an aryl group or an aryl ether group having from 6 to 12 carbon atoms is described.

This invention relates a process for preparing novel hydroxy 
alkyl(amido)acrylate and methacrylate monomers, to the novel monomers 
themselves and to polymers thereof and more particularly pertains to a 
process involving the reaction of an olefinically unsaturated carboxylic 
acid, such as acrylic acid, with a bicyclic amide acetal to form a hydroxy 
alkyl(amido)acrylate monomer and to the monomer itself and polymers 
prepared therefrom. 
Bicyclic amide acetals are known to react with carboxylic acids as 
disclosed in Synthesis, Page 16, 1971 to give the diester product. The 
preparation of hydroxy alkyl (amido) acrylate and methacrylate monomers by 
the reaction of acrylic acid or methacrylic acid with a bicyclic amide 
acetal has not previously been reported. 
I have discovered a process for preparing novel hydroxy 
alkyl(amido)acrylates and methacrylates (Formula III) by the reaction of a 
bicyclic amide acetal of Formula I with an olefinically unsaturated 
carboxylic acid of Formula II as shown in the following equation: 
##STR4## 
wherein R, R', R" and R"' independently represent hydrogen, an alkyl or 
alkyl ether group having from 1 to 20 carbon atoms, or an aryl or aryl 
ether group having from 6 to 12 carbon atoms. I have found that the rate 
of the foregoing reaction depends largely on the substituents present in 
the bicyclic amide acetal and for a given unsaturated acid the rate of the 
reaction follows the trend of: unsubstituted bicyclic amide acetal 
&gt;monosubstituted bicyclic amide acetal &gt;distribution bicyclic amide acetal 
&gt;tetrasubstituted bicyclic amide acetal. Thus, for instance, the reaction 
of methacrylic acid with unsubstituted bicyclic amide acetal (I) (R, R', 
and R" each represents hydrogen) is so rapid that a neat (solventless) 
reaction often tends to result in gelation. Similarly, monosubstituted 
bicyclic amide acetal when reacted with methacrylic acid at room 
temperature, gels rapidly. On the other hand, the methacrylic acid 
reaction with disubstituted bicyclic amide acetal proceeds smoothly to 
give the liquid monomer. Tetrasubstituted bicyclic amide acetals react 
with methacrylic acid slowly and generally require heat to complete the 
reaction. The formation of hydroxy alkyl (amido)methacrylates having low 
substitution from the reaction of monosubstituted bicyclic amide acetal 
(I) (R and R" represent hydrogen and R' represents an alkyl group) with 
methacrylic acid may conveniently be carried out in solvents which may 
include reactive monomers if copolymers are to be made subsequently. The 
hydroxy alkyl (amido) methacrylates can be prepared in situ in monomers 
such as methyl methacrylate, styrene, ethyl acrylate, butyl acrylate, and 
the like and can be copolymerized to give new copolymers after the monomer 
preparation is completed. Similarly, the hydroxy group of the hydroxy 
alkyl (amido) methacrylates can be caused to react with polyisocyanates to 
give unsaturated polyurethane polymers and the olefinically unsaturated 
moiety of the monomer can also be polymerized by vinyl polymerization 
either simultaneously or sequentially. Two moles of monomer III can be 
coupled with diisocyanate to give a diunsaturated monomer (diacrylate) 
which can be used as a crosslinker in vinyl monomer free radical type 
addition polymerization. 
The process for preparing the hydroxy alkyl(amido) acrylates of this 
invention may be carried out at a temperature in the range of from about 
0.degree. C. to about 100.degree. C. using a ratio of bicyclic amide 
acetal to acrylic or methacrylic acid in the range of from about 1:0.9 to 
about 0.9:I (molar) and preferably about 1:1. 
In the polymerization or copolymerization of the hydroxy 
alkyl(amido)acrylate monomers of this invention any free radical initiator 
known to those skilled in the art can be used such as peroxides, azo 
compounds, hydroperoxides, radiation, including ultraviolet, nuclear and 
X-ray types of radiation and even by heat alone. Specific initiators which 
can be used include t-butyl perbenzoate, t-butyl peroctoate, benzoyl 
peroxide, cumenehydroyperoxide, azobisisobutyronitrile and by anionic and 
cationic catalysts as is known in the art and the like and others.

This invention is further illustrated in the following representative 
examples. 
EXAMPLE 1 
To 6.4 g of bicyclic amide acetal of Formula I wherein R represents 
hydrogen, R' represents an ethyl group and R' represents CH.sub.2 
OCH.sub.2 CH.dbd.CH.sub.2 was added 2.6g of methacrylic acid at room 
temperature. An exotherm was observed, however, the GLC analysis of a 
small portion of the product after silylation with bis (trimethylsilyl) 
trifluoracetamide to block the unreacted methacrylic acid showed the 
presence of almost all of the starting materials. Thus the exotherm was 
probably caused by the acid-base salt formation. The reaction mixture was 
then heated under nitrogen at about 60.degree. C. with stirring and it 
appeared by periodic sampling and analysis that the reaction reached 
completion in about 16 minutes yielding product III where R is hydrogen, 
R' is an ethyl group R"' is CH.sub.2 OCH.sub.2 CH.dbd.CH.sub.2 and R"" is 
a methyl group. The infrared spectrum of the product showed bands at 3370 
cm.sup.-1 (Hydroxyl group), 1720 cm.sup.-1 (ester group), 1630 cm.sup.-1 
(amide group) showing the presence of product III. 
EXAMPLE 2 
The procedure of Example 1 was followed using 6.4 g of the bicyclic amide 
acetal described in Example 1 and 2.6 g of methacrylic acid. The resulting 
product was mixed with 9 g of styrene and 0.05 g of t-butyl perbenzoate. 
The solution which resulted was heated slowly and the temperature was 
raised to about 120.degree. C. Polymerization occurred to give a solid 
transparent polymer. The polymer was postcured at 120.degree.-130.degree. 
C. for one hour and the solid was found to be insoluble in toluene and 
tetrahydrofuran (THF). The Tg (softening point) for the polymer was 
determined to be 83.degree. C. by differential scanning calorimetry (DSC). 
EXAMPLE 3 
The procedure of Example 1 was followed using 12.9 g of a bicyclic amide 
acetal of Formula I wherein R and R" are hydrogen and R' is a methyl group 
and 8.5 g of methacrylic acid. An immediate, highly exothermic reaction 
occurred at room temperature to give a gelled mass suggesting the 
polymerization of the product III (R and R" are hydrogen and R' and R" ' 
are methyl). 
EXAMPLE 4 
To a 250 ml three-neck flask equipped with a stirrer, a thermometer, a 
water cooled condenser and a dropping funnel was added 20.8 g of styrene, 
17.2 g of methacrylic acid and 0.02 g of p-methoxyphenol (polymerization 
inhibitor). To this was then added dropwise 27.1 g of a bicyclic amide 
acetal of Formula I wherein R and R" are hydrogen and R' is methyl and the 
reaction temperature was maintained at about 24.degree. C. using an ice 
water bath for control. The reaction was continued for one hour and the 
resulting solution was analyzed by GLC which indicated almost complete 
reaction. The infrared spectrum of the product showed bands at 3350 
cm.sup.-1 (hydroxy group), 1720 cm.sup.-1 (ester carboxyl group) and 1630 
cm.sup.-1 (amide group). To this solution was added 0.2 g of 
t-butylperbenzoate and the resulting solution was heated at 120.degree. C. 
Polymerization occurred to give a solid transparent polymer. The Tg (DSC) 
of the polymer product was found to be 78.degree. C. 
EXAMPLE 5 
The procedure of Example 4 was followed using 20 g of methyl methacrylate 
as solvent, 7.2 g of methacrylic acid and 27.`g of the bicyclic amide 
acetal. The resulting mixture containing the product III in methyl 
methacrylate solution 1720 cm.sup.-1 and 1630 cm.sup.-1 . showed infrared 
bands at 3362 cm.sup.-1, The resulting mixture was then subjected to 
polymerization. The clear, transparent solid polymer which resulted was 
found to have a Tg of 73.3.degree. C. by DSC and a thermal decomposition 
point in nitrogen of 300.degree. C. 
EXAMPLE 6 
To a solution of 37 g of dipropylene glycol and 8.6 g of methacrylic acid 
was added 3.5 g of a bicyclic amide acetal of Formula I wherein R and R" 
are hydrogen and R' is a methyl group, and the reaction mixture was 
stirred at room temperature for one hour. The resulting solution was 
degassed at reduced pressure and was then mixed with 0.1 g of t-butyl 
peroctoate, 0.3 g of N,N',N" -tris(dimethylamino propyl) hexahydrotriazine 
and 92 g of degassed carbodimide modified methylene bis(phenyl isocyanate) 
(NCO equivalent weight of 144). The resulting solution was poured into a 
hot mold kept at 100.degree. C. and prepared by using two parallel 
silicone mold release coated glass plates held apart by 1/8 inch thick 
spacers. Polymerization occurred rapidly to give a solid polymer sheet 
which was postcured at 130.degree. C. for 30 minutes. The final polymer 
sheet was found by analysis to have anotched izod impact strength (ASTM 
D256) of 0.8 foot pounds/inch of notch and a heat distortion temperature 
(ASTM D648) of 110.degree. C. 
EXAMPLE 7 
To a solution of 35 g of butyl acrylate sovent and 5 g of methacrylic acid 
was added 8 g of a bicyclic amide acetal of Formula I wherein R and R" are 
hydrogen and R' is a methyl group. The resulting solution was stirred at 
room temperature for one hour. To this solution was then added an 
additional 40 g of the bicyclic amide acetal and 0.2 g of t-butyl 
peroctoate and this was mixed rapidly with 113 g of modified liquid 
methylene bis(phenyl isocyanate) (isocyanate functionality of 2.1 NCO per 
molecule) and the resulting solution was poured into the glass mold 
described in Example 6. The polymer which resulted after postcuring as 
described in Example 6 was found to have a notched izod impact strength of 
0.9 foot pounds/inch of notch and a heat distortion temperature of 
123.degree. C.