Method for preparing an adhesive tape or molding mass
A polymerizable composition which may be used as an adhesive mass in a method for preparing an adhesive tape or as molding mass in a method for preparing molded articles is provided. The polymerizable composition contains: A) a thermal cationic initiator, or B) a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers in such an amount that the heat energy released during polymerization is sufficient for cleaving the thermal initiator. The adhesive mass is curable via a local impulse a) of thermal energy orb) of thermal energy and/or radiation energy through frontal polymerization; or the molding mass is initially prepared by mixing all components and then molded into the desired shape, whereafter its frontal polymerization is induced by a local impulse a) of thermal energy and/or b) of radiation energy in order to prepare a cured molded article.
1 . A method of preparing an adhesive tape comprising using a polymerizable composition comprising cationically polymerizable monomers, at least one cationic polymerization initiator, and optionally one or more additives, as an adhesive mass, wherein the polymerizable composition comprises as the at least one cationic polymerization initiator:
A) a thermal cationic initiator, or
B) a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers in such an amount that the heat energy released during polymerization is sufficient for causing cleavage of the thermal initiator, so that the adhesive mass is curable via a local impulse a) of thermal energy or b) of thermal energy and/or radiation energy through frontal polymerization,
wherein the polymerizable composition is prepared by mixing all components contained therein, whereafter it is, as an adhesive mass, applied in the form of a layer
a) onto a carrier or
b) onto a release sheet to form a transfer adhesive tape;
whereafter optionally the exposed surface of the layer is covered with a) a release sheet or b) another release sheet.
2 . A method for preparing molded articles comprising using a polymerizable composition comprising cationically polymerizable monomers, at least one cationic polymerization initiator, and optionally one or more additives, wherein the polymerizable composition comprises as the at least one cationic polymerization initiator:
A) a thermal cationic initiator, or
B) a combination of a cationic photoinitiator and a thermal free-radical initiator for inducing the polymerization of the cationically polymerizable monomers in such an amount that the heat energy released during polymerization is sufficient in order to cause cleavage of the thermal initiator; and
a molding mass is initially prepared by mixing all components contained therein and then molded into the desired shape, whereafter its frontal polymerization is induced by a local impulse of thermal energy and/or radiation energy in order to prepare a cured molded article;
wherein the polymerizable composition used as the molding mass
is spreadable-pasty before molding and, for molding, is applied as a spackle, filler or mortar onto uneven surfaces or
is solid, but plastically moldable, before molding and is used as a modelling mass or putty and molded into the desired shape manually or by means of a tool;
whereafter it is frontally polymerized in this shape;
and optionally wherein, before molding, one or more viscosity modifiers, thickeners and/or rheology modifiers are added to the polymerizable composition in order to adjust predefined viscosities or flow properties.
3 . The method according to claim 1 , wherein the thermal cationic initiator is selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium, benzylpyridinium, methylimidazonium, benzylpyrazinium or substituted benzylphosphonium salts of non-nucleophilic bases of very strong acids as anions,
wherein the cationic photoinitiator is optionally selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium, benzylpyridinium, methylimidazolium, benzylpyrazinium or substituted benzylphosphonium salts of B(C 6 F 5 )4-, SbF 6 − , AsF 6 —, PF 6 — or BF 4 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion or mixtures thereof, and
wherein the thermal cationic initiator is optionally selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium salts of SbF 6 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion.
4 . The method according to claim 1 , wherein:
i) the cationic photoinitiator is selected from aryl-substituted iodonium, phosphonium, sulfonium, pyridinium or diazonium salts,
wherein the cationic photoinitiator is optionally selected from diaryliodonium salts of non-nucleophilic bases of very strong acids as anions and mixtures thereof,
wherein the cationic photoinitiator is optionally selected from diaryliodonium salts of B(C 6 F 5 )4-, SbF 6 —, AsF 6 —, PF 6 —, BF 4 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion or mixtures thereof; and/or
ii) the thermal free-radical initiator is selected from benzopinacol or derivatives thereof, peroxides or azo compounds, wherein the thermal free-radical initiator is optionally selected from benzopinacol, dibenzoylperoxide or azobis(isobutyronitrile), wherein the thermal free-radical initiator is optionally benzopinacol.
5 . The method according to claim 1 , wherein the cationic photoinitiator is selected from (4-octyloxyphenyl)(phenyl)iodonium hexafluoroantimonate, bis(4-dodecylphenyl)iodonium hexafluoroantimonate, (4-isopropylphenyl)(4′-methylphenyl)iodonium tetrakis(pentafluorophenyl)borate, or iodonium salts of the tetrakis(perfluoro-t-butyloxy)-aluminate anion.
6 . The method according to claim 1 , wherein the cationic polymerizable monomers are selected from monovalent or multivalent epoxides (oxiranes), thiiranes (episulfides), oxetanes, lactams, lactones, lactides, glycolides, tetrahydrofuran or mixtures thereof.
7 . The method according to claim 1 , wherein in the polymerizable composition,
a) the thermal cationic initiator is present in a proportion of 0.5 to 6 wt. %-based on the total weight of the cationic polymerizable monomers; or
b1) the cationic photoinitiator and the thermal free-radical initiator of the initiator combination are present in a molar ratio of 1:0.5 to 1:45; and/or
b2) the initiator combination is present in a proportion of 0.5 to 12 wt. % based on the total weight of the cationic polymerizable monomers.
8 . The method according to claim 1 , wherein the polymerizable composition further comprises additives selected from the group consisting of thickeners and rheology modifiers, coupling agents, tackifiers, network, impact strength and surface modifiers, film-forming agents, wetting agents, pigments, coloring agents, stabilizers, control agents, flame retardants or fillers, and/or radically polymerizable monomers.
9 . The method according to claim 1 , wherein the adhesive mass is
applied in the form of a layer onto a carrier selected from paper, fabrics, non-woven materials, plastic foils, metal foils, foams, or combinations thereof, wherein the carrier is optionally fiber-reinforced.
10 . An adhesive tape prepared by to the method according to claim 1 .
11 . A cured molded article prepared by to the method of claim 2 .
12 . The method according to claim 2 , wherein the thermal cationic initiator is selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium, benzylpyridinium, methylimidazonium, benzylpyrazinium or substituted benzylphosphonium salts of non-nucleophilic bases of very strong acids as anions,
wherein the cationic photoinitiator is optionally selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium, benzylpyridinium, methylimidazolium, benzylpyrazinium or substituted benzylphosphonium salts of B(C 6 F 5 )4-, SbF 6 − , AsF 6 —, PF 6 — or BF 4 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion or mixtures thereof, and
wherein the thermal cationic initiator is optionally selected from alkylbenzylsulfonium or alkylarylbenzylsulfonium salts of SbF 6 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion.
13 . The method according to claim 1 , wherein:
i) the cationic photoinitiator is selected from aryl-substituted iodonium, phosphonium, sulfonium, pyridinium or diazonium salts,
wherein the cationic photoinitiator is optionally selected from diaryliodonium salts of non-nucleophilic bases of very strong acids as anions and mixtures thereof, wherein the cationic photoinitiator is optionally selected from diaryliodonium salts of B(C 6 F 5 )4-, SbF 6 —, AsF 6 —, PF 6 —, BF 4 — or the tetrakis(perfluoro-t-butyloxy)aluminate anion or mixtures thereof; and/or
ii) the thermal free-radical initiator is selected from benzopinacol or derivatives thereof, peroxides or azo compounds, wherein the thermal free-radical initiator is optionally selected from benzopinacol, dibenzoylperoxide or azobis(isobutyronitrile), wherein the thermal free-radical initiator is optionally benzopinacol.
14 . The method according to claim 2 , wherein the cationic photoinitiator is selected from (4-octyloxyphenyl)(phenyl)iodonium hexafluoroantimonate, bis(4-dodecyl-phenyl)iodonium hexafluoroantimonate, (4-isopropylphenyl)(4′-methylphenyl) iodonium tetrakis-(pentafluorophenyl)borate, or iodonium salts of the tetrakis(perfluoro-t-butyloxy)aluminate anion.
15 . The method according to claim 2 , wherein the cationic polymerizable monomers are selected from monovalent or multivalent epoxides (oxiranes), thiiranes (episulfides), oxetanes, lactams, lactones, lactides, glycolides, tetrahydrofuran or mixtures thereof.
16 . The method according to claim 2 , wherein in the polymerizable composition,
a) the thermal cationic initiator is present in a proportion of 0.5 to 6 wt. %-based on the total weight of the cationic polymerizable monomers; or
b1) the cationic photoinitiator and the thermal free-radical initiator of the initiator combination are present in a molar ratio of 1:0.5 to 1:45; and/or
b2) the initiator combination is present in a proportion of 0.5 to 12 wt. % based on the total weight of the cationic polymerizable monomers.
17 . The method according to claim 2 , wherein the polymerizable composition further comprises additives selected from the group consisting of thickeners and rheology modifiers, coupling agents, tackifiers, network, impact strength and surface modifiers, film-forming agents, wetting agents, pigments, coloring agents, stabilizers, control agents, flame retardants or fillers, and/or radically polymerizable monomers.