Epoxidized acetals and thioacetals, episulfidized acetals and thioacetals, and reworkable thermosetting resin compositions formulated therefrom

A thermosetting resin composition, reaction products of which are capable of softening and losing their adhesiveness under exposure to temperature conditions in excess of those used to cure the composition, said composition comprising:

• (a) a curable resin component, at least a portion of which comprises the combination of
• (i) a first reworkable curable resin selected from the group consisting of limonene diepoxide, gamma-terpinene diepoxide, methyl cyclopentadiene diepoxide dimer, ethylidene norbornene diepoxide, nopol epoxide glycidyl ether, and combinations thereof;
• and
• (ii) a second reworkable curable resin selected from the group consisting of an aromatic compound having at least two thermally cleavable [aromatic] acetal or thioacetal linkages and at least two reactive groups selected from the group consisting of epoxy groups, episulfide groups, and combinations thereof;
• and
• (b) a curing agent component selected from the group consisting of anhydrides, nitrogen-containing compounds, polythiols, polyphenols, polycarboxylic acids, onium salts, and combinations thereof.

A curable aromatic compound having at least two thermally cleavable linkages, and at least two reactive groups selected from the group consisting of epoxy groups, episulfide groups, and combinations thereof, wherein the curable aromatic compound is a member selected from the group consisting of:

• wherein:
• X is an oxygen atom or a sulfur atom;
• Ar represents a single aromatic ring nucleus or multiple aromatic ring nuclei, which may be fused or linked through direct covalent bonds, oxygen atoms, sulfur atoms, ketone groups, sulfoxide groups, sulfone groups, C1-6 alkylene or C2-6 alkenylene groups optionally substituted with trifluoromethyl groups, or poly (C2-4 oxyalkylene) and the aromatic ring(s) may be further optionally substituted with C1-6 alkyl, C3-8 cyloalkyl, C2-6 alkenyl, alkoxy groups, acetyl groups, or methylol groups;
• n represents an integer between 2 and 6 when Ar is a single aromatic ring nucleus and an integer between 2 and 8 when Ar is a multiple aromatic ring nuclei;
• Y is an oxygen atom, an alkylene group or a carbonyl group;
• R1 is hydrogen or alkyl;
• R2 is C1-8 alkyl, C2-9 alkenyl or C6-11 aryl group;
• R3 is C1-15 alkylene, C3-15 cycloalkylene, C7-15 bicycloalkylene, C2-15 alkenylene, C5-15 cycloalkenylene, C7-30 bicycloalkenylene, C1-15 alkylene ester, C2-15 alkylene ether, C2-30 alkenylene ester, C2-15 alkenylene ether, phenylene, phenylene ether, or phenylene ester, each of which may be optionally substituted with one or more hydroxyl, alkoxy, or ester or interrupted with one or more ester, ether, or carbamate groups;
• R4, R5, R6, R7, R8 are independently H, C1-12 alkyl, alkenyl, cyclo- or bicyclo-alkyl, cyclo- or bicyclo-alkenyl, or aryl;
• and
• E represents an aliphatic, cycloaliphatic or bicycloaliphatic epoxide or episulfide group having the structure indicated by E1-E4:
• wherein R9 is a H atom or a C1-6 alkyl group, X is as defined above and the wavy line indicates the attachment to R3 of structure I and II.

A thermosetting resin composition, reaction products of which are capable of softening and losing their adhesiveness under exposure to temperature conditions in excess of those used to cure the composition, said composition comprising:

• (a) a curable resin component, at least a portion of which comprises an aromatic compound having at least two thermally cleavable linkage and at least two reactive groups selected from the group consisting of epoxy groups, episulfide groups, and combinations thereof;
• and
• (b) a curing agent component selected from the group consisting of anhydrides, nitrogen-containing compounds, polythiols, polyphenols, polycarboxylic acids, onium salts, and combinations thereof, wherein the aromatic compound having at least two thermally cleavable linkages is selected from those within the following structures I and II:
• wherein:
• X is an oxygen atom or a sulfur atom;
• Ar represents a single aromatic ring nucleus or multiple aromatic ring nuclei, which may be fused or linked through direct covalent bonds, oxygen atoms, sulfur atoms, ketone groups, sulfoxide groups, sulfone groups, C1-6 alkylene or C2-6 alkenylene groups optionally substituted with trifluoromethyl groups, or poly(C2-4 oxyalkylene), and the aromatic ring(s) may be further optionally substituted with C1-6 alkyl, C3-8 cyloalkyl, C2-6 alkenyl, alkoxy groups, acetyl groups, or methylol groups;
• n represents an integer between 2 and 6 when Ar is a single aromatic ring nucleus and an integer between 2 and 8 when Ar is a multiple aromatic ring nuclei;
• Y is a member selected from the group consisting of an oxygen atom, an alkylene group, and a carbonyl group;
• R1 is a hydrogen atom or an alkyl group;
• R2 is a member selected from the group consisting of C1-8 alkyl group, C2-8 alkenyl groups and C6-11 aryl groups;
• R3 is C1-15 alkylene, C3-15 cycloalkylene, C7-15 bicycloalkylene, C2-15 alkenylene, C5-15 cycloalkenylene, C7-30 bicycloalkenylene, C1-15 alkylene ester, C2-15 alkylene ether, C2-30 alkenylene ester, C2-15 alkenylene ether, phenylene, phenylene ether, or phenylene ester, each of which may be optionally substituted with one or more hydroxyl, alkoxy, or ester, or interrupted with one or more ester, ether, or carbamate groups;
• R4, R5, R6, R7, and R8 are independently H, C1-12 alkyl, alkenyl, cyclo- or bicyclo-alkyl, cyclo- or bicyclo-alkenyl, or aryl;
• and
• E is a member selected from the group consisting of an aliphatic, cycloaliphatic or bicycloaliphatic epoxide or episulfide group having a structure indicated by E1-E4:
• wherein R9 is a hydrogen atom or an alkyl group, X is as defined above and the wavy line indicates the attachment to R3 of structure I and II.